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Structural geology and timing of deformation at the Gibraltar copper-molybdenum porphyry deposit, south-central… Mostaghimi, Nader 2016

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Structural Geology and Timing of Deformation at the Gibraltar Copper-Molybdenum Porphyry Deposit, south-central British ColumbiabyNADER MOSTAGHIMIB.Sc. (Hons), The University of Waterloo, 2012A THESIS SUBMITTED IN PARTIAL FULFILLMENT OFTHE REQUIREMENTS FOR THE DEGREE OFMASTER OF SCIENCEinThe Faculty of Graduate and Postdoctoral Studies(Geological Sciences)THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver)April 2016© Nader Mostaghimi, 2016iiAbstractThe Gibraltar Cu-Mo porphyry deposit, near Williams Lake in south-central British Columbia, is hosted in the Late Triassic Granite Mountain batholith. The main ore zone, hosted within the Mine Phase tonalite, is variably deformed and structurally dismembered. Alteration assemblages are used to map out the geometry of deformation. Quartz-chlorite (QC) alteration is strongly associated with mineralization, and QC and ankerite-quartz (AQ) are associated with ductile shear zones (thrust faults) that typically host or bound the ore. Deformation structures are divided into two deformation events, D1 and D2. D1 contains a variably developed, tectonic foliation (S1) that is folded into gentle to open folds. S1 is associated with shallowly to moderately south- to southwest-dipping ductile thrust faults and smaller-scale imbricate ductile thrusts that deform the Gibraltar porphyry system. D2 resulted in the formation of NW- to NE- (N-S) trending dextral faults ± normal displacement, and variably striking low-angle normal faults (e.g., northeast-striking Fault 10) that offset (~60 to <220 metres of vertical- and/or lateral-slip separation) and rotate (CW) D1 and mineralization. Shallowly SE-plunging mineral lineations (e.g., intersections (LI) and fold axes (F2) are associated with a sub-horizontal crenulation cleavage (S2) that likely formed during extension. The Mine Phase tonalite yields a U-Pb (zircon) crystallization age of ca. 216.17 ± 0.24 Ma (CA-TIMS). In contrast, Ar-Ar (white mica) minimum cooling ages ranged from 54-36 ± 5 Ma for mica collected from S1, ductile thrusts faults, and N-S striking, dextral faults ± normal displacement. It is proposed that D1 and D2 are associated with movement along the Paleocene-Eocene, dextral strike-slip, Quesnel River and Fraser River fault systems, and therefore deformation significantly post-dates porphyry emplacement. This interpretation is supported by deformation microstructures in quartz and plagioclase that constrain the temperatures during deformation to be less than 450°C; too low to be contemporaneous with pluton emplacement. iiiPrefaceDr. B. Anderson (Geological Survey of Canada, Vancouver) identified and designed the research program in conjunction with the Targeted Geoscience Initiative-4 (TGI-4) involving deep intrusion-related ore deposits; Dr. L. Kennedy was approached by the Natural Resources Canada. The research, sampling and data accumulation were performed by N. Mostaghimi in consultation with L. Kennedy. Dr. K. Hickey contributed with concept formation of the thesis as an external supervisor.Chapter 1 contains a regional map (Figure 1.1) modified after Nelson and Colpron (2007) by the author of this thesis. Figure 1.4.is modified after Ash and Riveros (2001).Chapter 2 of the thesis is intended for publication in a scientific journal under a different title. N. Mostaghimi will be first author, and L. Kennedy will be second author. Preliminary work from Chapter 2 was published in the Summary of Activities Geoscience BC 2014 [Mostaghimi, N. and Kennedy, L. (2015): Structural geology of the Granite Lake pit, Gibraltar copper-molybdenum mine, south-central British Columbia: preliminary observations; in Geoscience BC Summary of Activities 2014, Report 2015-1, p. 129–140]. I was the primary author responsible for data collection, manuscript composition, and concept formation. L. Kennedy was a supervisory author who was involved with concept formation and initial manuscript edits. P. Schiarizza contributed to final manuscript edits and concept formation. Photographs in Figure 2.6, and diamond drill data and shape files used in Leapfrog® Geo were obtained from Gibraltar Mines Ltd.. Stereographs in Figure 2.50C and D are modified after Campbell (2013; in-house report by BGC Engineering Inc.) by the author of this thesis. Figure 2.49 is modified after Bysouth et al. (1995), also by the author of this thesis.Geochronology data, including Ar-Ar white mica and hornblende analyses were acquired by J. Gabites at the Pacific Centre for Geochemical and Isotopic Research (PCIGR) at the University of British Columbia, Vancouver, Canada. U-Pb zircon (CA-TIMS) geochronology data was produced by R. Friedman, also at PCIGR, Vancouver, Canada.ivTable of ContentsAbstract                                                                                                        iiPreface                                                                                                        iiiTable of Contents                                                                                             ivList of Tables                                                                                                 viiiList of Figures                                                                                                ixAcknowledgements                                                                                         xiiiDedication                                                                                                    xivChapter 1 Introduction                                                                                        11.1  Background and Introduction                                                                         11.2  Objectives of Study                                                                                    11.3  Typical versus Deformed Porphyry Deposits                                                         31.4  Previous Work                                                                                         41.4.1 Regional Geology                                                                                  41.4.2 Regional Structural Geology                                                                      91.4.3 Mine Site Geology                                                                                101.4.4 Alteration                                                                                         151.4.4.1 Albite-Clinozoisite-Epidote-Chlorite (Deuteric) Alteration                              151.4.4.2 Chlorite-Epidote (Propylitic) Alteration                                                  151.4.4.3 Quartz-Chlorite (QC) Alteration                                                           171.4.4.4 Quartz-Sericite (QS) and Quartz-Sericite-Chlorite (QSC) Alteration                   171.4.4.5 Quartz-Sericite-Pyrite (QSP) Alteration                                                                          171.4.4.6 Iron Carbonate-Quartz Alteration                                                                                   181.4.4.7 Other Alteration Assemblages and Veins                                                181.4.4.8 Supergene Zone                                                                            181.4.5 Mineralization                                                                                    191.4.6 Structural Geology                                                                               201.4.7 Mine Exploration History                                                                        221.5  Thesis Organization                                                                                   26Chapter 2 Structural Geology, Kinematics, and Timing of Deformation at the Gibraltar  porphyry deposit                                                                                            282.1  Introduction                                                                                           282.2  Methodology                                                                                         302.3  Mine Site Geology                                                                                    33v2.3.1 Lithology                                                                                         332.3.1.1 Mine Phase Tonalite                                                                        332.3.1.2 Feldspathic Mine Phase Tonalite                                                          362.3.1.3 Leucocratic Tonalite Dikes                                                                 402.3.2 Spatial Distribution of Intrusive Rocks                                                         402.3.3 Alteration and Veins                                                                             432.3.3.1 Deuteric Alteration: Albite-Clinozoisite-Epidote-Chlorite                              432.3.3.2 Chlorite-Epidote (Propylitic) Alteration                                                  472.3.3.3 Quartz-Chlorite (QC) Alteration                                                           482.3.3.4 Quartz-Sericite-Pyrite (QSP) Alteration                                                                          502.3.3.5 Quartz-Sericite (QS) and Quartz-Sericite-Chlorite (QSC) Alteration                   542.3.3.6 Ankerite-Quartz (AQ) Alteration                                                          542.3.3.7 Fe-Oxides and Clay Alteration                                                             552.3.4 Mineralization                                                                                    552.3.4.1 Cu-oxides                                                                                    562.4  Structural Geology - Field and Microstructural Observations                                     572.4.1 Magmatic Foliation (Sm)                                                                         662.4.2 D1 Structures                                                                                      662.4.2.1 The Main Foliation (S1)                                                                    662.4.2.2 Veins and Veinlets Spatially Associated With S1                                         732.4.2.3 Ductile Thrust Faults                                                                       762.4.2.3.1 Microstructure of Ductile Thrust Faults                                            822.4.2.3.2 Folds                                                                                  882.4.2.3.3 Boudinaged Quartz (BQ) Veins                                                      882.4.3 D2a Structures                                                                                    892.4.3.1 N-S Striking Dextral Faults ± Normal Displacement                                     892.4.3.2 D2a Microstructures                                                                        962.4.4.2.1 N-S Striking Dextral Faults ± Normal Displacement                                962.4.4 D2b Structures                                                                                    992.4.4.1 Extensional Structures                                                                     992.4.4.2 Shallowly SE Plunging Fabric (S2)                                                          992.4.4.2 D2b Microstructures                                                                       1062.4.4.2.1 S2                                                                                     1062.5  Pit-Scale Cross Sections                                                                            106vi2.5.1 Interpolated Orebody and Structures                                                        1072.5.1.1 Results                                                                                     1072.5.2 Vein Orientation Analysis across Zones of Variable Deformation and Alteration         1102.5.2.1 Results                                                                                     1102.5.3 Cross Section Representations of Deformation, Alteration and Mineralization in the Granite Lake pit                                                                                             1122.5.3.1 Results                                                                                     1172.6  Geochronology                                                                                      1192.6.1 U-Pb Zircon Geochronology                                                                   1212.6.1.1 Mine Phase tonalite; NM-13-009                                                       1212.6.1.2 Methodology                                                                             1212.6.1.3 Results                                                                                     1232 6 2 40Ar/39Ar White Mica and Hornblende Geochronology                                       1262.6.2.1 X-ray diffraction (XRD) analytical techniques                                           1262.6.2.2 Results of XRD Analyses                                                                 1282.6.2.3 Sample Descriptions                                                                     1282.6.2.4 Methodology                                                                             1402.6.2.5 Results                                                                                     1422.6.3 Summary of Results                                                                            1522.7  Discussion                                                                                           1552.7.1 Sequence, Style, and Physical Conditions of Deformation Events Affecting the Deposit 1552.7.2 Timing of Deformation Relative to Late Triassic Porphyry Mineralization                 1572.7.3 Strain Localization in Hydrothermally Altered Rocks                                        1602.7.4 Gibraltar Deformation in Regional Geologic Context                                       1612.7.5 Structural Model for the Evolution of the Gibraltar Cu-Mo deposit                       1652.7.5.1 Structures Related to the Pinchi Fault System                                         1662.7.5.2 Structures Related to the Fraser Fault System                                         1662.7.6 Evidence for Ore Remobilization during Deformation                                      1692.7.7 Structure as a Guide to Exploration for more Ore                                          169Chapter 3 Conclusions                                                                                     1723 1 Conclusions                                                                                          1723.2  Recommendations for Future Work                                                               173References                                                                                                  175Appendix A Structural Field Data                                                                         189viiAppendix B Sample Data                                                                                   205Appendix C Petrographic Data                                                                            222Appendix D Drill Core Data                                                                                255Appendix E Graphic Logs For Selected Drill Holes                                                       316Appendix F Cross Section Methodologies                                                                323Appendix G TCu% Interpolant Construction                                                             331Appendix H Cross Section Data                                                                           338Appendix I XRD Data                                                                                      355Appendix J Geochronology Data                                                                          357viiiList of TablesTable 1 1 Summary of vein classifications of pervious workers compared to this study   .  .  .  .  .  .  .  16Table 1 2 Summary table of mineral showings within the Granite Mountain batholith  . . . . . . . . 23Table 2 1 Summary of mapped bench walls and associated samples . . . . . . . . . . . . . . . . . . 32Table 2 2 Vein types and their associated alteration assemblages, and temporal relationships   .  .  .  44Table 2 3 Summarized chart of Gibraltar veins/veinlets and their intensity of deformation   .  .  .  .  .  77Table 2 4 Gibraltar mine D1 structures and their characteristics . . . . . . . . . . . . . . . . . . . . . 80Table 2 5 Gibraltar mine D2 structures and their characteristics . . . . . . . . . . . . . . . . . . . . . 91Table 2 6 Gibraltar mine extensional structures associated with D2, and their characteristics  .  .  .  .101Table 2 7 U-Pb analytical results for zircon from the Mine Phase tonalite of the Granite Mountain  . . .                    batholith from Gibraltar mine  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .124Table 2 8 Table of 001 illite XRD reflection data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .132Table 2 9 40Ar/39Ar analytical results for hornblende from the feldspathic Mine Phase tonalite, and   .  .                   white mica from various structures and fabrics   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .143Table 2 10 Summary chart of 40Ar/39Ar plateau and inverse isochron ages for the Mine Phase tonalite  .                    and structures at Gibraltar porphyry   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .147ixList of FiguresFigure 1 1 Terrane map of British Columbia showing various Cu-Mo ± Au and Cu-Au ± Mo deposits   . 2Figure 1 2 Typical versus conceptual deformed Cu porphyry system  . . . . . . . . . . . . . . . . . . . 5Figure 1 3 Regional geology map of the Granite Mountain batholith . . . . . . . . . . . . . . . . . . . 7Figure 1 4 General location of moderately-dipping high-strain zones and NNE-trending sinistral and                          dextral faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Figure 1 5 Summary of published geochronological data for the Granite Mountain batholith intrusive                    phases and Gibraltar porphyry mineralization   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  13Figure 2 1 Regional geology map of the Granite Mountain batholith and Gibraltar mine area . . . . 29Figure 2 2 Taseko Mines pits, bench maps, and sample locations . . . . . . . . . . . . . . . . . . . . 31Figure 2 3 Alteration paragenesis and representative finite (cumulative) alteration sections . . . . . 34Figure 2 4 Geological map of the Gibraltar mine area  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  37Figure 2 5 Rock types within the Gibraltar mine   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  38Figure 2 6 Drill core samples from Granite Lake pit illustrating alteration assemblages in the Gibraltar                     porphyry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41Figure 2 7 Gibraltar mine pit map illustrating the distribution of alteration zones . . . . . . . . . . . 46Figure 2 8 Main mineralization occurrences at Gibraltar mine . . . . . . . . . . . . . . . . . . . . . . 49Figure 2 9 Mineralization in large quartz veins and secondary enrichment   .  .  .  .  .  .  .  .  .  .  .  .  .  .  52Figure 2 10 Granite Lake West bench walls and strip maps   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  58Figure 2 11 Granite Lake West 3770'-3950' ramp (West Connector Ramp) bench wall and strip map 59Figure 2 12 South Granite Lake 3800' bench wall and strip map . . . . . . . . . . . . . . . . . . . . . 61Figure 2 13 3725' bench wall and strip map in Granite Lake East  . . . . . . . . . . . . . . . . . . . . 63Figure 2 14 Pollyanna 3870' bench wall and strip map . . . . . . . . . . . . . . . . . . . . . . . . . . 64Figure 2 15 Tectonic foliation (S1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67Figure 2 16 Equal-area stereographic projections of structural elements from various pits at the                      Gibraltar Mine   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  68Figure 2 17 Mylonitic fabrics  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  71Figure 2 18 Cross cutting relationships between S1 and mineralization-stage veinlets . . . . . . . . . 74Figure 2 19 Granite Lake Faults of the Granite Lake pit . . . . . . . . . . . . . . . . . . . . . . . . . . 79Figure 2 20 Imbricate ductile thrust faults on Granite Lake West 3770'-3950' ramp   .  .  .  .  .  .  .  .  .  83Figure 2 21 Ductile thrust fault microstructures   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  86Figure 2 22 N-S striking, dextral faults ± normal displacement   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  90Figure 2 23 Fabrics associated with N-S striking, dextral faults ± normal displacement . . . . . . . . 94Figure 2 24 Microstructures in dextral strike-slip faults   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  97xFigure 2 25 Extensional fault: Fault 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100Figure 2 26 Low-angle imbricate imbricate ductile thrust fault shows contradicting kinematic                      indicators in meso- and micro-scale   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .102Figure 2 27 S2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .104Figure 2 28 TCu% interpolated orebody constructed for Granite Lake pit with three-dimensional                      modeling aid   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .108Figure 2 29 Graphic representation of mineralization-hosting veins and veinlets parallel (<15) and                      oblique (≥15) to foliation (α angle) in zones of rock with variable foliation and alteration                       intensities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111Figure 2 30 Cross section locations in the Granite Lake pit . . . . . . . . . . . . . . . . . . . . . . . .113Figure 2 31 N-S cross section D-D'  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .114Figure 2 32 N-S cross section E-E' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115Figure 2 33 E-W cross section G-G' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .116Figure 2 34 Ar-Ar white mica and hornblende and U-Pb zircon geochronology sample locations at                      Gibraltar mine   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .120Figure 2 35 Mine Phase tonalite collected for U-Pb zircon CA-TIMS geochronology . . . . . . . . . .122Figure 2 36 Concordia plot for U-Pb zircon CA-TIMS geochronology  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .125Figure 2 37 Sample collected for Ar-Ar hornblende geochronology of feldspathic Mine Phase tonalite .   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .131Figure 2 38 Figure of diagnostic 001 reflection data obtained from XRD analysis of white mica                      separates used for 40Ar/39Ar (white mica) geochronology . . . . . . . . . . . . . . . . . .132Figure 2 39 Sample collected for 40Ar/39Ar (white mica) geochronology of the S1 fabric . . . . . . . .133Figure 2 40 Sample collected for 40Ar/39Ar (white mica) geochronology of the strike-slip movement in                      the N-S direction on a normal dextral fault.  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .134Figure 2 41 Sample collected for 40Ar/39Ar (white mica) geochronology of an imbricate ductile thrust                      fault with northeast vergence and top-to-the-northeast kinematics   .  .  .  .  .  .  .  .  .  .  .135Figure 2 42 Sample collected for 40Ar/39Ar (white mica) geochronology of a sub-horizontal ductile                      shear zone that envelopes a quartz vein which strikes WNW   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .136Figure 2 43 Sample collected for 40Ar/39Ar (white mica) geochronology of the shear fabric within the                      sub-horizontal to shallowly dipping northeast, ductile shear zone . . . . . . . . . . . . .137Figure 2 44 Sample collected for 40Ar/39Ar (white mica) geochronology of a fabric that defines a                      northeast-dipping, conjugate ductile thrust fault  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .138Figure 2 45 Sample collected for 40Ar/39Ar (white mica) geochronology of a fabric defining reverse and                      normal kinematics in a northeast vergent imbricate ductile thrust   .  .  .  .  .  .  .  .  .  .  .  .139xiFigure 2 46 Interpreted plateau ages for Ar-Ar hornblende and white mica geochronology. . . . . .148Figure 2 47 Summary of geochronological analyses for the intrusive phases of the Granite Mountain                      batholith and mineralization at the Cu-Mo Gibraltar porphyry . . . . . . . . . . . . . . .154Figure 2 48 Summary of Ar-Ar (white mica) plateau ages of various structural elements at Gibraltar                      mine and their temporal relationships  . . . . . . . . . . . . . . . . . . . . . . . . . . . .154Figure 2 49 Regional Geology and Faults of the Granite Mountain map area   .  .  .  .  .  .  .  .  .  .  .  .  .158Figure 2 50 Schematic maps of the main regional deformation events affecting the Granite Mountain                      batholith and their relative timing   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .162Appendix A1 Gibraltar West 2950' bench wall and strip map  . . . . . . . . . . . . . . . . . . . . . .204Appendix C1 Microstructures in a quartz-sericite-molybdenite (QSM) vein  . . . . . . . . . . . . . .254Appendix E1 Graphic log for drill hole 2006-021  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .317Appendix E2 Graphic log for drill hole 2006-028  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .318Appendix E3 Graphic log for drill hole 2007-098  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .319Appendix E4 Graphic log for drill hole 2007-101  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .320Appendix E5 Graphic log for drill hole 2010-020  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .321Appendix E6 Graphic log for drill hole 2011-001  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .322Appendix G1 Screenshot images of values used to create the TCu% interpolant in Leapfrog® Geo                         modeling program  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .332Appendix G2 Geometric data for selected orebody interpolants  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .333Appendix G3 Axes that define TCu% orebody interpolants A-D . . . . . . . . . . . . . . . . . . . . .334Appendix G4 Axes that define TCu% orebody interpolants E-H  . . . . . . . . . . . . . . . . . . . . .335Appendix G5 Fault kinematics and displacement estimates determined with the utilization of three-                        dimensional visualization aid   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .337Appendix H1 Hand drawn N-S cross section A-A' . . . . . . . . . . . . . . . . . . . . . . . . . . . . .341Appendix H2 Hand drawn N-S cross section B-B'  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .342Appendix H3 Hand drawn N-S cross section C-C'  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .343Appendix H4 Hand drawn N-S cross section D-D' . . . . . . . . . . . . . . . . . . . . . . . . . . . . .344Appendix H5 Hand drawn N-S cross section E-E'  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .345Appendix H6 Hand drawn N-S cross section F-F'  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .346Appendix H7 Hand drawn E-W cross section G-G'   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .347Appendix H8 Hand drawn N-S cross section H-H' . . . . . . . . . . . . . . . . . . . . . . . . . . . . .348Appendix H9 Hand drawn E-W cross section I-I'   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .349Appendix H10 Hand drawn E-W cross section J-J'.  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .350Appendix H11 N-S cross section A-A'   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .351xiiAppendix H12 N-S cross section B-B' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .352Appendix H13 N-S cross section C-C' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .353Appendix H14 N-S cross section F-F' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .354Appendix I1 XRD data of white mica separates used for 40Ar/39Ar geochronology . . . . . . . . . . .356Appendix J1 Interpreted inverse isochron graphs for Ar-Ar hornblende and white mica geochronology     .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .358xiiiAcknowledgementsI would like to express my deepest gratitude to my supervisor Lori Kennedy for the opportunity to take on this project and for sharing her vast depth of knowledge with me that always leaves me in awe. I am thankful for your patience throughout this project, and for teaching me so much about structural geology.I owe many thanks to Taseko Mines Ltd. for allowing access to the pits, the drill core and their database. In particular, Lyshia Goodhue was so instrumental in my data collection process, this project could not have achieved what it did without you, thank you. I appreciate the continuous and willing assistance provided by Janina Micko at Leapfrog® as I navigated my way through your program.I would like to thank the faculty and staff of the Department of Earth, Ocean and Atmospheric Sciences for their support and access to all of their resources. I am very thankful for Rich Friedman and Janet Gabites (PCIGR) for their preparatory lab work for U-Pb and Ar-Ar geochronology, as well as their incessant assistance throughout my study. I would also like to thank Mati Raudsepp and Lan Kato for training and guidance through the x-ray diffraction analysis; and Arne Toma and Sara Jenkins (MDRU) who I would repeatedly bother for various tasks and were always so helpful. I wish to express my appreciation and gratitude to other educators and supervisors, J. Mortensen, K. Hickey, and specifically B. van Straaten is thanked for sharing his knowledge regarding the alteration and for beneficial discussions. I would like to give a special thanks to Paul Schiarizza of the British Columbia Geological Survey for his continuous insight and expertise in the geology of the south-central British Columbia region, and for always being so approachable. Lastly, I'd like to thank my family and friends who have stuck by me through this roller-coaster ride experience; all of whom I hope to spend more time with upon the completion of my M.Sc.Natural Resources Canada and Geoscience BC each provided partial funding and for this project.xivDedicationTo my loving parents who have always been there for me. Thank you for your unrelenting support.1Chapter 1 Introduction1.1  Background and IntroductionThe Gibraltar mine is situated about 65 km north-northeast of Williams Lake in south-central British Columbia. It is hosted in a Late Triassic, large calc-alkaline copper-molybdenum porphyry deposit that is heterogeneously deformed by both ductile and brittle processes. Although the orebodies at Gibraltar are undoubtedly structurally controlled, the timing, kinematics and mechanism of deformation are still disputed, and are the focus of this research. The emplacement of many copper porphyry deposits is structurally controlled by large-scale regional structures (e.g., La Escondida and Chuquicamata, in Chile, and Bingham, USA); however, most of these deposits are not internally strained by ductile deformation (Ossandon et al., 2001; Richards et al., 2001; Lindsay et al., 1995; Cornejo et al., 1997; Lindsay, 1998; Gruen et al., 2010). Internally strained copper porphyry deposits are less common. For example, the Mitchell Cu-Au deposit, located in NW British Columbia (Febbo et al., 2015), was deformed ductiley, by post emplacement processes. The Minto Au-Cu-Ag porphyry deposit, located in the Yukon Territory (Figure 1.1), is thought to have been emplaced under a differential stress and the intense ductile strain within the porphyry developed during emplacement (i.e., a syntectonic intrusion) at a minimum depth of 10-15 km (Tafti, 2005; Hood, 2012). In northern Chile, the movement along the Domeyko Fault System was synchronous with magmatic activity associated with emplacement of porphyry-style mineralization, and this facilitated ductile deformation of the porphyry at shallow depths (i.e., 1-3 km for Potrerillos-El Salvador; (Mpodozis et al., 1994; Tomlinson, 1994). The Gibraltar Cu-Mo porphyry, similar to the these deposits, has a close spatial association between the ore hosting hydrothermal alteration, mineralization, and zones of ductile deformation (Oliver, 2008; van Straaten et al., 2013); however, the relative timing of intrusion, mineralization and deformation at Gibraltar has not yet been resolved.1.2  Objectives of StudyThis project is part of the Geological Survey of Canada’s Intrusion Related Ore Systems TGI-4 program where the Gibraltar copper-molybdenum open-pit mine is one of several mineralized systems currently being investigated. The objectives of this study are to, 1) unravel the geometry and kinematics of deformation that have affected ore distribution, 2) place constraints on the timing 2LorraineMt. MilliganRed ChrisBrendaHighlandValleyAfton, AjaxSimilcoKemessGalore Cr., Copper CanyonMintoMt. PolleyBig MissouriPremierSchaft Cr.Rossland Gp.NicolaGp.HazeltonGp.TaklaGp.LewesRiverGp.TaklaGp.StuhiniGp.PacificOceanArcticOceaneasterNWTABU.S.A.BCB.C.AK TYTWNTYTYAncestral North America(Laurentia)Peri-LaurentianrealmCu-Mo(±Au) Porphyry-styledepositsCu-Au(±Mo) Porphyry-style depositsTriassic-Jurassic arcvolcanic and plutonic beltsQuesnellia, StikiniaPaleozoic pericratonicfragmentsMetamorphic belt, mainlyYukon-Tanana/StikineSlide Mountain terraneCache Creek terrane: Mesozoicforearc accretionary assemblage0 200km72°N58°N68°N50°N58°N144°W144°W124°W132°W160°W62°N120°WBCYTTreatySulphuretsMiddleJurassicriftCACHE CREEK SUTURE(ca. 172-174 Ma)CHE CREEK S TURE. 172-174 Ma) Pitman faultNahlinFaultFaultFaultThibertBOWSERBASINBASINKingSalmonYTYT STSTSTQNQNNAmNAmSMCCmmCatfaceBergHuckleberryHushamuGibraltarIsland CopperCasinoProsperitydeformatinonlimiteasternofCordilleran Figure 1.1 Terrane map of British Columbia showing various Cu-Mo ± Au and Cu-Au ± Mo deposits; Nelson and Colpron (2007); Penteleyev (2005); Sinclair (2007).3of deformation structures, and 3) determine whether batholith emplacement and mineralization were synkinematic with the earliest deformation structures or structural modification of the deposit occurred after emplacement and mineralization. This study integrates pit mapping, drill core observations and petrographic studies to reconstruct the structural evolution of the Gibraltar deposit area. 1.3  Typical versus Deformed Porphyry Deposits Porphyry deposits are characterized by their large size, low- to medium-grades, and ore that is generally associated with vein sets, stockworks, breccias, and fractures (Sinclair, 2007). Porphyry deposits typically occur in root zones of stratovolcanoes in subduction-related, continental-arc and island-arc settings (Sillitoe, 1973; Sinclair, 2007) at 1-4 km in depth, but they may also occur as deep as 9 km (Dilles et al., 1999; Singer et al., 2008), a depth of emplacement suggested by Oliver et al. (2009) for the Gibraltar porphyry. Many porphyry deposits occur in extensional regimes, within contractional settings where crustal thickening, surface uplift, and rapid exhumation are empirically related to large Cu porphyry deposits around the world (Sillitoe, 2010). Porphyry systems, including their orebodies can range in shape and size but are generally large (>100*106 tonnes), with relatively low ore grades (ca. 1% Cu; Sinclair, 2007). Porphyry deposits are generally enveloped with zones of hydrothermally altered rock in which the mineralogy varies both with depth and laterally/radially away from the pluton (Lowell and Guilbert, 1970). Since this model was proposed by Lowell and Guilbert (1970), a large number of variations have been described, that refine the alteration and mineralization assemblages (i.e., Eastoe, 1983; Dilles and Einaudi, 1992; Gustafson and Quiroga, 1995). Typical alteration patterns in Cu-Mo porphyry deposits include a barren core that is adjacent to a potassic alteration zone comprising K-feldspar and/or biotite, ± magnetite ± anhydrite ± hornblende (Lowell and Guilbert, 1970; Sillitoe, 2010). An outer propylitic alteration zone normally contains minimal mineralization and contains quartz, chlorite, epidote, calcite and locally, albite associated with pyrite (Rowins, 2000). Phyllic (sericite + quartz + pyrite) and argillic (intermediate and advanced) alteration (quartz + illite + pyrite ± kaolinite ± smectite ± montmorillonite ± calcite) zones can be irregular or tabular, in some cases situated between the potassic and propylitic zones (Sinclair, 2007; Sillitoe, 2010). Mineralization in porphyry deposits occurs both in veins and as disseminations depending 4on the deposit. Fe, Cu, and Mo sulphides are localized in the heavily fractured upper parts of felsic intrusives or adjacent country rocks (Beane and Titley, 1981) and 80-90% of ore minerals are vein and veinlet-hosted (Hollister, 1978; Beane and Titley, 1981). Porphyry deposits that were emplaced under no differential stress (i.e., emplaced under a confining pressure (ρgh)) are modelled to have a radiating fracture pattern that emanates from the pluton (Figure 1.2A). In contrast, a porphyry emplaced under a differential stress in a compressional regime at sufficient depths (e.g., >6-9 km) to promote ductility, would likely develop an alteration halo oriented parallel to a developing fabric (e.g., foliation). In this case, veins would not occur radially around the pluton; rather, veins would likely form sub-parallel to σ1 (the most compressive stress orientation in a compressional regime) and the alteration halos would also be oriented more or less horizontally away from the pluton (Figure 1.2B). In porphyry deposits formed under differential stress within a ductile zone (>15 km depth), veins are rare and mineralization is commonly disseminated (Minto; Tafti, 2005; Hood, 2012). Porphyry deposits emplaced under a differential stress in the brittle-ductile transition zone (~10-15 km depth), like the Butte deposit, contain veins formed through hydraulic fracturing that may host-sulphides (Houston and Dilles, 2013).1.4  Previous Work1.4.1 Regional GeologyThe Granite Mountain batholith (GMB) is located within the Intermontane Belt, which is part of a collage of oceanic terranes and volcanic arc complexes that accreted onto the western margin of the Laurentian craton from the Early Mesozoic to the Late Paleocene (Monger, 1985; Nelson and Colpron, 2007). These terranes include the Quesnel terrane, an important metallogenic province that occurs the length of the Canadian Cordillera (Figure 1.1; Nelson et al., 2013), and the Cache Creek terrane, an accretionary complex related to east-dipping subduction that generated the Quesnel magmatic arc. The GMB, a calc-alkaline arc-related pluton (Oliver et al., 2009), intrudes the Intermontane Belt.The Quesnel terrane formed above the eastward subducting Cache Creek terrane during the amalgamation of the Intermontane Belt from the Late Permian to Early Jurassic (Monger, 1985; Nelson et al., 2006). The ancestral ocean between the Quesnel terrane to the east and the Stikine terrane to the west closed around the Middle Jurassic, and is linked to the formation of the Quesnel ASteamheatedVuggy residualquartz/silicicationMultiphaseporphyrystockQuartz-aluniteQuartz-kaoliniteChloriticChlorite-sericite PropyliticPotassicSericitic1 km1 kmQuartz-pyrophylliteB1 km1 kmSyntectonic PorphyryσStockwork veins?Stockwork veinsSheeted veins Sheeted veins1Typical Telescoped Cu PorphyryFigure 1.2 Typical versus conceptual deformed Cu porphyry system. A. Schematic drawing of a generic alteration-mineralization zonation pattern proposed for a Cu-porphyry system (modified after Sillitoe, 2010). B. A simple conceptual model for vein, porphyry, and alteration geometry for a generic Cu-porphyry system when emplaced under a differential stress. Hydrothermal sheeted veins, dykes and to some extent, plutonic rocks are emplaced sub-parallel to σ1.6magmatic arc (Travers, 1982; Mortimer, 1986; Cordey et al. 1987; Mortimer, 1987; Mortimer et al., 1990; Struik et al., 2001; Mihalynuk et al., 2004). This coincides with the earliest deformation of the Intermontane Belt that resulted in contractional deformation causing northeast verging rock units and thrusting (Gabrielse et al., 1992).From Middle Cretaceous to Paleocene, the increased obliquity of the plate boundary along the paleomargin of North America resulted in widespread transcurrent dextral faulting and extensional collapse, associated with decompression melting and exhumation of mid-crustal rocks in the Intermontane Belt and surrounding regions (Ewing, 1980; Parrish et al., 1988; Struik, 1993). High-angle, normal faults, and low-angle detachment faults signify Eocene extensional faulting in southeastern British Columbia, as noted by Wernicke et al. (1987) and Gabrielse et al. (1992). Two significant dextral strike-slip faults that loosely bound the GMB are the Quesnel River fault (a southeastern extension of the Pinchi fault system) and the Fraser River fault system, which also defines the boundary between the Cache Creek and Quesnel terranes in south-central British Columbia (refer to Figure 1.3), and records approximately 200 km of dextral offset that mostly occurred in the Middle Cretaceous (Wyld et al., 2006). However, it has been proposed that at specific localities along the fault, movement continued into the Eocene (Gabrielse et al., 2006). The north-south trending Fraser River fault system that lies to the west of the GMB, records ~100 km of dextral offset from Middle Eocene (Kleinspehn, 1985) to Late Eocene (Gabrielse et al., 1992).The first regional mapping of the Quesnel River map area (93B) was conducted by Tipper (1959, 1978). More detailed geological mapping of the Granite Mountain map area was conducted by Panteleyev (1978), Ash et al. (1998a, b), Logan et al. (2010), and Schiarizza (2015). The Intermontane Belt in this region is composed of Late Paleozoic through Early Mesozoic oceanic rocks (mostly chert, limestone and basalt) of the Cache Creek Complex (Cache Creek terrane), and Late Triassic through Middle Jurassic arc volcanic, volcaniclastic and plutonic rocks of the Quesnel terrane. The Granite Mountain batholith (GMB) is fault bounded against meta-volcanic sedimentary rocks of the Late Triassic Nicola Group, and meta-sediments of the Early to Middle Jurassic Dragon Mountain succession, both of which are assigned to the Quesnel terrane (Tipper, 1978; Logan and Moynihan, 2009; Schiarizza, 2015). The Dragon Mountain succession contains a conglomerate unit of which contains quartz diorite and tonalite clasts that are similar to the quartz diorite and tonalite of 7River9797McLeese LakeWilliams LakeQuesnel0 20km53.01°52.10°121.50°123.00°Miocene - PleistoceneMiddle Jurassic (in part)Oligocene - PlioceneQuaternaryEarly CretaceousEocene Late TriassicBasalt, andesite, rhyolite, volcanicbreccia, sandstone, conglomerateSyenite, monzonite,monzodioriteBasaltGranite, granodioriteConglomerate, sandstoneUnconsolidated glacial,fluvial and alluvial depositsTonalite, quartz diorite,granodioriteCretaceous?Lower to Middle JurassicConglomerate, sandstone, shaleGranite Mountain batholithBurgess Creeek stock:tonalite, quartz diorite, dioriteConglomerate, sandstone,siltstoneQuesnel Terrane Middle Triassic - Early JurassicPhyllite, quartzite, limestoneVolcanic sandstone, breccia,basalt; monzonite, dioritePericratonic RocksSlide Mountain TerraneCache Creek TerraneDevonian - PermianCarboniferous - Lower JurassicCuisson Lake belt Proterozoic - PaleozoicBasalt, chert, amphibolite,gabbro, serpentiniteBasalt, chert, limestone, sandstone,siltstone, serpentinite, gabbroChlorite schist, limestone, skarn,chlorite-sericite-quartz-feldspar schist Quartzite, pelitic schist, marble;chlorite schist, foliated graniteGibraltar MineFraserGranite Mountain phase:leucocratic tonaliteMine phase: tonaliteBorder phase: diorite, quartz dioriteFraser Fault SystemQuesnel River Fault Figure 1.3 Regional geology map of the Granite Mountain batholith from Schiarizza (2015). Bold dashed lines represent fault traces, projected above Neogene and Quaternary cover. The Gibraltar mine open pits are outlined within the inset box. 8the Granite Mountain batholith (e.g., Tipper, 1978). Limited exposures of cherts, phyllite, limestone and basalts of the Cache Creek terrane lie east and northeast of the GMB stock, but are mostly covered by unconsolidated Quaternary glacial, alluvial, and colluvial deposits (Figure 1.3; Schiarizza, 2014; 2015).The GMB is bounded to the south by the Sheridan Creek stock; an Early Cretaceous tonalitic plutonic suite (108.1 ± 0.6 Ma, U-Pb zircon; Ash and Riveros, 2001); and by the Burgess Creek stock the northeast (Schiarizza, 2014) (Figure 1.3). The Burgess Creek stock has previously been interpreted as a relatively young, post-GMB intrusion (Panteleyev, 1978; Bysouth et al., 1995) or a border phase of the GMB (Ash et al., 1999a, b). Recent U-Pb zircon ages from Schiarizza (2015) however, yield 222.71 ± 0.22 Ma (tonalite) and 221.25 ± 0.20 Ma (quartz diorite), both of which are older than any from the GMB. Younger rocks in the area include Middle Jurassic and Early Cretaceous granitic plutons, Eocene volcanic and sedimentary rocks, Oligocene–Pliocene clastic sedimentary sequences, and widespread Miocene–Pleistocene basalt of the Chilcotin Group. Historically, the GMB was interpreted as having intruded the Cache Creek Complex, in part because of widespread Cache Creek exposures to the east and south of the batholith (e.g., Sutherland Brown, 1974; Drummond et al., 1976; Bysouth et al., 1995; Oliver et al., 2009). Hence, the GMB was thought to be a part of the Cache Creek terrane. Ash et al. (1999a, b) and Schiarizza (2014, 2015) suggest that the GMB is officially part of the Quesnel terrane. Contacts between the batholith and the Cache Creek Complex are faults, but intrusive contacts are preserved along the northeastern margin of the batholith where it and related plutonic rocks of the Burgess Creek stock intrude Upper Triassic volcaniclastic and volcanic sequence correlated with the Nicola Group of the Quesnel terrane. These relationships led Schiarizza (2015) to conclude that the GMB is part of the Quesnel terrane, and part of a panel of Quesnel terrane rocks that is faulted against the Cache Creek terrane to the west of the main Quesnel belt (Figure 1.1). Its age and location within the western part of Quesnel suggest that the GMB is broadly correlative with the Late Triassic Guichon Creek batholith, which hosts the Highland Valley copper-molybdenum porphyry deposits located 250 km to the south-southeast (Schiarizza, 2014). This trend is correlative to the metallogenic province that extends northwest from southeastern British Columbia into Yukon Territory and is hosted in the Quesnel and Stikine terranes 9(Figure 1.1; Nelson and Colpron, 2007).1.4.2 Regional Structural GeologyThe structural geology of the regional geologic units as summarized herein is described in detail by Schiarizza (2015), who sub-divides the structural geology into three domains: a northern, southern, and eastern domain. The northern domain contains the Nicola Group, the Burgess Creek stock, and the Dragon Mountain succession. The southern domain is composed of the GMB, the "mafic-rich phase" (Cuisson Lake unit; Schiarizza, 2014; 2015), and the Sheridan Creek stock. Lastly, the eastern domain comprises the Cache Creek Complex. In the northern domain, the rocks in the southern portion of the Nicola Group are right-way-up and contains a well-developed foliation that dips moderately to the east-southeast. To the northeast, the Nicola Group is stratigraphically overlain by conglomerates of the Dragon Mountain succession that also dips moderately towards the northeast. The slate-sandstone unit of the Dragon Mountain succession to the west dips towards the west. The slaty cleavage of the Dragon Mountain slate-sandstone unit dips mainly to the northeast but locally to the southwest, and is axial planar to mesoscopic folds that plunge northwest. Mesoscopic folds and crenulations with south- to southeast-plunges also deform the Dragon Mountain succession. The Burgess Creek stock cross cuts the Nicola Group at a high angle. Local, steeply-dipping mylonitic shear zones in the Burgess Creek stock are cross cut by tonalite and leucocratic phases of the stock. These shear zones are interpreted to have formed during emplacement of the stock. In the southern domain, the GMB contains a foliation with a gentle to moderate dip towards the south. This foliation is much stronger in the mafic-rich phase. The intensity of the foliation in the Sheridan Creek stock and the GMB is highly variable. Generally, the isotropic igneous texture in the Granite Mountain phase trondhjemite is overprinted by discontinuous sericite-foliae and slight flattening of chloritized mafic knots. Strongly foliated rocks contain an anastomosing network of sericite-rich and chlorite-rich folia that enclose lenses of flattened quartz and saussuritic (and internally strained) plagioclase. These relationships indicate mostly flattening kinematics, with localized zones of well-foliated rocks with S-C fabrics that show top-to-the-north shear sense. The S1 of the GMB is cross cut by a crenulation cleavage that is steeply dipping towards the SSW and strikes 10ESE. South-plunging kink folds and crenulations with north-striking, steeply-dipping axial surfaces are suspected to be younger structures that deform the mafic-rich phase. Similarly, a south-dipping high strain zone cuts the Sheridan Creek stock.The eastern domain contains a well-foliated chert-phyllite with limestone and basalt that show little to no foliation. The foliation in the Cache Creek complex dips at low to moderate angles to the north. This foliation is deformed by mesoscopic folds and east- to southeast-plunging folds where foliation dips to the south. The foliation is also cross cut by a weak crenulation cleavage that dips steeply towards the south and steeply to the ESE.An east-trending fault is inferred between the Sheridan Creek stock and the Mafic-rich phase of the GMB, but may also be a north-directed thrust fault (Ash and Riveros, 2001). A northeast-trending fault with sinistral shear sense, truncates the mafic-rich, Border, and Mine phases of the GMB and juxtaposes them against the Sheridan Creek stock to the southeast. Extrapolation of this fault may juxtapose the GMB with the Cache Creek complex to the northeast. Northeast-trending faults are also inferred to the north of the GMB based on map unit truncations. North and north-northwest trending faults observed in the south, offset the mafic-rich phase and Sheridan Creek stock by an apparent 750 metres (Schiarizza, 2015). The extension of this fault truncates the eastern boundary of the Gibraltar mine orebodies and correlates to the East Boundary Fault that bifurcates into the Saddle Fault at the GL pit. To the west approximately 2300 metres, the Sawmill fault also offsets the mafic-rich and Border phases of the GMB, and may fault the western boundary of the GMB (Bysouth et al., 1995). Lastly, a series of north-northwest trending faults to the north of the GMB are inferred to have mainly dextral and/or west side-down movement (Schiarizza, 2015). These NNW-trending faults and the northeast-trending faults are suspected to be associated with Cretaceous and Eocene related dextral faults (Struik, 1993). 1.4.3 Mine Site GeologyThe Gibraltar Cu-Mo mine consists of four main pits; Granite Lake, Pollyanna, Gibraltar East, and Gibraltar West (Figure 1.4). Gibraltar North and Sawmill Zone are two other main ore zones that are not yet mined out; and the Connector pit is an ore zone that is located between Pollyanna, Granite Lake and Gibraltar East, and is yet to be mined. The Gibraltar mine is situated geographically 11185817000N1920551000EPipelineGibraltarWestGraniteMine phasetonaliteTrondhjemiteLakePollyannaGibraltarEastModerately-dipping shearzone; dened, inferredArea of  folding andshearing in footwall ofmoderately-dipping shear zones Lithological contactLate hematite-richfaults; dened, inferredMill Site1397 mGraniteMtnFigure 1.4 General location of moderately-dipping high-strain zones (Granite Lake Faults (GLFs) Oliver, 2007) and young, NNE-trending sinistral and dextral faults at Gibraltar mines (modified after Ash & Riveros, 2001). Base map is taken from Google Earth (2015).12in the centre of the GMB. The GMB is divided into 5 intrusive phases that become increasingly felsic in composition from the south to the north of the batholith (e.g., Tipper, 1959; 1978; Eastwood, 1970; Panteleyev, 1978; Bysouth et al., 1995; Ash et al., 1999) The phases from south to north are: the mafic-rich phase (Cuisson Lake unit; Schiarizza, 2015), Border Phase quartz diorite, the mine-hosting Mine Phase tonalite, Granite Mountain Phase trondhjemite, and the leucocratic tonalite dikes. Bysouth et al. (1995) show that the GMB compositions are consistent with calc-alkaline “I-type” granitoids related to porphyry deposits (Ishihara, 1981). Bysouth et al. (1995) also noted the steady increase in felsic (K2O) content of the batholith phases towards the north-northeast, and inversely decreasing MgO content, along with decreasing normative An (%) from the Border phase quartz diorite to the Granite Mountain trondhjemite phase. The mafic-rich phase consists of chlorite-sericite-quartz-feldspar schist and epidote-chlorite-garnet skarn that crops out immediately southwest of the border phase diorite (van Straaten et al., 2013). This schist was previously interpreted as a metamorphosed unit of the Cache Creek Group by Drummond et al. (1976), Panteleyev (1978) and Bysouth et al. (1995). Ash et al. (1998, 1999) interpreted this schist as a sheared unit of the GMB due to the presence of hornblende-rich diorite and minor hornblendite in low-strain zones of the chlorite-sericite-quartz-feldspar schist (Ash et al., 1998; van Straaten et al., 2014). Ash and Riveros (2001) revised their interpretation to include some melanocratic units of the GMB with volcanic rocks of the Cache Creek Group. The Border Phase quartz diorite is composed of 15% quartz, 45–50% plagioclase and 35% chloritized hornblende and is found in the southwestern segment of the batholith (Bysouth et al., 1995; van Straaten et al., 2013).The Late Triassic Mine Phase tonalite, the most abundant rock type in the field area, is intruded by leucocratic tonalite dikes that are similar in age to mineralization of the Gibraltar porphyry. Previous geochronologic analysis conducted by Oliver et al. (2009) yielded a U-Pb zircon age of 211.9 ± 4.3 Ma, which coincides with a Re-Os molybdenum age of 210-215 Ma (Harding, 2012; Figure 1.5). An estimated 98% of the ore-hosting rock mass is contained within the Mine Phase tonalite. Unaltered and undeformed Mine Phase tonalite is uncommon, but where observed is composed of 15-25% quartz, 40-50% plagioclase, and 25-35% chlorite (after hornblende), and is generally equigranular with grain sizes between 2-4 mm (van Straaten et al., 2013). The Mine Phase tonalite contains a volumetrically minor, relatively undeformed and unaltered feldspathic 13Feldspathic MinePhase tonaliteGranite MountainPhase trondhjemiteLeucocratictonalite dikesMineralization220 210 200215.0±0.8215.0±1.0212.7±0.9210.1±0.9212.0±0.4208±12Age  (Ma)211.9±4.3209.6±6.3217.15±0.20Mine PhasetonaliteTriassic Jurassic(1)(2)(1)(3)(5)(3)(4)(4)(4)U-Pb (zircon)K-Ar (hornblende)Re-Os (molybdenite)Figure 1.5 Summary of published geochronological data for the Granite Mountain batholith intrusive phases and Gibraltar porphyry mineralization (modified after van Straaten et al., 2013) Data drawn from: 1. Oliver et al. (2009); 2. Drummond et al. (1976), recalculated by Breitsprecher and Mortensen (2004) using IUGS decay constants; 3. Ash and Riveros (2001); 4. Harding (2012); 5. Schiarizza (2015). Double dashed-line represents the Triassic-Jurassic period boundary.14variety that contains fresh hornblende and andesine that rims plagioclase. The feldspathic Mine Phase tonalite crops out in the southern parts of Granite Lake pit (Drummond et al, 1976; Oliver, 2007a; 2008; van Straaten et al., 2013). The feldspathic Mine Phase tonalite K-Ar cooling age was recalculated by Breitsprecher and Mortensen (2004) to yield 208 ± 12 Ma, after a sample collected by Drummond et al. (1976) (Figure 1.5). Leucocratic dikes (porphyritic quartz diorite facies of Eastwood, 1970; leucocratic phase of Bysouth et al., 1995; leucocratic quartz porphyry dikes of van Straaten et al., 2013), are not abundant, and strike northwest and dip to the southwest (Oliver, 2008). The dikes are white in colour, contain less than 10-15% mafic minerals, may host mineralization, but generally contain less mineralization than the Mine Phase tonalite (van Straaten et al., 2013). One of several northeasterly dipping leucocratic dikes from the Pollyanna pit yielded a U-Pb zircon age of 212 ± 0.4 Ma (reported by Ash and Riveros, 2001, without providing any details). A sample of a quartz-plagioclase porphyry dike that cuts Mine Phase tonalite 4 km southeast of Gibraltar mine was submitted for U-Pb zircon geochronology using CA-TIMS (Schiarizza, 2015). These phases are described in more detail in Chapter 2.The Granite Mountain Phase trondhjemite forms the north-northeast boundary to the Mine Phase tonalite (and hence mineralization). The boundary is interpreted to be a normal fault, the “North Graben fault” (NGF; Figure 1.4; Oliver, 2008). The Granite Mountain Phase trondhjemite comprises ≥45% quartz, 45% plagioclase, and 10% chlorite, with an average grain size of 2-4 mm, and is generally barren to weakly mineralized when intercepted at depth in Granite Lake, Pollyanna, and Gibraltar East pits, below the main orebodies (van Straaten et al., 2013). The Granite Mountain Phase trondhjemite and leucocratic phase are logged interchangeably in historic drill core. Three U-Pb zircon ages have been previously reported; one sample, 1.5 km north-northeast of the Gibraltar mill site (Ash et al., 1999a) yielded a U-Pb zircon age of 215 ± 0.8 Ma (Ash and Riveros, 2001). Schiarizza (2015) reported a sample of leucocratic tonalite (Granite Mountain Phase trondhjemite) collected north-northeast about 6 km from Gibraltar mine, near the contact of the leucocratic phase of the Burgess Creek stock that yielded an age of 217.15 ± 0.20 Ma. Both ages precede the age of mineralization and agree with Oliver et al. (2009), who reported that a sample of Granite Mountain Phase yielded a U-Pb age of 209.6 ± 6.3 Ma (Figure 1.5).151.4.4 AlterationHypogene alteration at Gibraltar is discussed in detail by various authors (Eastwood, 1970; Sutherland Brown, 1974; Drummond et al., 1976; Bysouth et al., 1995; Oliver, 2006; van Straaten et al., 2013; 2014). Eastwood (1970) first proposed that the deposit is of a porphyry style. Bysouth et al. (1995) provided geochemical analyses of the intrusive phases and the alteration assemblages. Oliver (2006) produced a coding system with assigned alteration mineral assemblages. These alteration assemblages, vein types, and mineralization distributions are modified by van Straaten et al. (2013; 2014) and further modified in this study. Previous workers (Sutherland Brown, 1974; Drummond et al., 1976) have provided their own vein characterization schemes (see Table 1.1). Generally, a positive correlation exists between deformation intensity, alteration, and mineralization (e.g., Oliver, 2007b; van Straaten et al., 2013). Oliver (2008) observed structural stacking and repeating of alteration zones by faults in Gibraltar East.In this study, alteration assemblages were used as mappable ‘units’, during both pit mapping and core logging. Using alteration assemblages as units permitted the correlation of units within the mine pits, and hence facilitated the correlation of structural panels within and between mine pits. In general, there is a positive correlation between the sericite content and strain intensity of the rocks. Below, the alteration assemblages defined by previous workers are described; these assemblages are described in more detail in Chapter 2.1.4.4.1 Albite-Clinozoisite-Epidote-Chlorite (Deuteric) AlterationDeuteric alteration consists of saussuritization of plagioclase to albite-clinozoisite-epidote-sericite, and chlorite (Bysouth et al., 1995). Plagioclase in the form of andesine is altered to albite (Bysouth et al., 1995) and variably altered to epidote, clinozoisite-zoisite, and sericite. Oliver (2006; 2007a, b) mapped unaltered and deuterically altered rock predominantly on the periphery of the Granite Lake pit, associated with the feldspathic Mine Phase tonalite in the southwest portion of the Granite Lake pit, and to the immediate west-southwest of the Granite Lake pit.1.4.4.2 Chlorite-Epidote (Propylitic) AlterationPropylitic alteration contains the earliest mineralization-stage. It consists of pale yellow-green saussuritization of plagioclase, chloritization of mafics, discrete epidote veinlets, thin 1-2 mm wide chlorite-pyrite ± chalcopyrite veins, and minor sulphides in epidote veins (Oliver, 2007; van Straaten 16Table 1.1 Summary of vein classifications of previous workers compared to this studyVein Assemblage This study; modified after van Straaten et al. (2013; 2014) van Straaten et al. (2013; 2014)Harding (2012); refers to Gustafson and Hunt (1975), Sillitoe (2010)Drummond et al. (1972) Sutherland Brown (1974) Ep Ep ~ ~ ~ ~Chl + Ep ± Py ± Cpy ± Qtz ± CbPA, PB a) thin, planar; b) wider, diffuse margins; c) wider, diffuse Qtz-envelope; d) Cb and cubic Py in the centre ± Cpy~ Stage 1. (a) qtz+py±cpy with ser envelope: qtz+ser+py±cpy (b) qtz+chl+py±mag±cb with chl envelope: qtz+chl+py±cpyV1Qtz ± Chl ± Mag ± Py ± Cpy ± MoQC a) sharp boundaries; b) no margins, grey Qtz; and c) disconnected, wavy veins with more diffuse Qtz-Chl marginsB-veins Stage 2. (a) qtz+chl+py±mag (b) qtz+chl+py+cpy+ep±mag (c) qtz+chl+py+ep±mag (d) qtz+chl+py+cpy±mag (e) qtz+cpy+bn+±py±cbV2Qtz + Ser + Py ± Cpy ± Moa) QSP ~ D-veins: 1. Fine grained foliation parallel disseminations associated with a) qtz, b) white mica filled microfractures; 2. coarser, aggregates of platy and tabular grains Stage 3 (?). qtz+mo+cpy+py±mag±cbV3 (?)Qtz + Ser + Mo + Py ± Cpyb) QSM ~ ~ Stage 3. qtz+mo+cpy+py±mag±cbV3 Qtz + Chl ± Cpy ± Py ± CbBQ ~ ~ Stage 4. bull qtz+blebs of fine grained chl+blebs of cpyV4 Qtz Barren Qtz Barren, milky-white planar Qtz- veins with sharp margins cross-cut all veins~ ~ ~Ank Ank Thin, 1-2 mm in width. Often seen infilling micro-fractures in other veins~ ~ ~Ank ~ Ank* ~ ~ ~17et al., 2013). Surface coating of hematite is described by van Straaten et al. (2013; 2014) in localized intervals in drill core logging. Oliver (2007a, b; 2008) noted that propylitic alteration and chlorite-quartz (quartz-chlorite) alteration (see below) are gradational and overlap one another. When absent in the rocks, propylitic alteration is generally considered to be overprinted by subsequent alteration.1.4.4.3 Quartz-Chlorite (QC) AlterationThe quartz-chlorite alteration assemblage (chlorite-quartz (cq) alteration assemblage of Oliver, 2006; van Straaten et al., 2013; 2014) hosts the majority of the mineralization at Gibraltar mine. Harding (2012) highlights the similarities of the veins that compose the quartz-chlorite alteration assemblage to ‘B-veins’ described by Gustafson and Hunt (1975) and Sillitoe (2010) (Table 1.1). This alteration assemblage is dominated by quartz-chlorite veins that host chalcopyrite. The matrix contains elevated amounts of dark green chlorite and minor smokey grey quartz, making it difficult to distinguish from the propylitic phase (Oliver, 2006; 2007a).1.4.4.4 Quartz-Sericite (QS) and Quartz-Sericite-Chlorite (QSC) AlterationPervasive grey quartz and white to grey sericite (QS) alteration overprint propylitic and QC alteration, and replace chlorite and feldspar with sericite. There are no veins associated with this alteration phase. Quartz-sericite-chlorite (QSC) alteration is described as an intermediate phase between chlorite-quartz (quartz-chlorite) and quartz- sericite alteration assemblages. QSC alteration is also pervasive, but generally confined to smaller intervals compared to QS alteration (van Straaten et al., 2013; 2014), and even more texturally destructive than QS alteration with strongly enhanced fabrics. The QSC alteration assemblage is likely the biotite-sericite-quartz (BCQ) alteration assemblage of Oliver (2006; 2007a).1.4.4.5 Quartz-Sericite-Pyrite AlterationOliver (2006) first used the quartz-sericite-pyrite to represent phyllic (Lowell and Guilbert, 1970; Sillitoe, 2010) alteration. This alteration assemblage comprises two main vein types: 1) quartz and coarse euhedral pyrite occur as veins that can be sheeted, oriented parallel to foliation and in stockwork orientation (Oliver, 2007a), commonly with a diffuse grey sericitic envelope; and 2) milky-white, quartz-sericite-pyrite-molybdenite vein (comparative to ‘D-veins’; Gustafson and Hunt, 1970; Sillitoe, 2010; van Straaten et al., 2013; Table 1.1) that are reported to contain the bulk of the molybdenite mineralization (Harding, 2012). The matrix can be altered with silica and sericite flooding 18with pyrite mineralization; similar to the QS alteration assemblage.1.4.4.6 Iron Carbonate-Quartz AlterationPale iron carbonate (ankerite)-quartz alteration assemblage (Oliver; 2007; van Straaten et al., 2013; 2014) contains a laminar fabric defined by sericite and chlorite folia, and is generally associated with high strain zones (van Straaten et al., 2013). Ankerite or related iron carbonate generally occur as wisps aligned parallel to a foliation (van Straaten et al., 2013).1.4.4.7 Other Alteration Assemblages and VeinsZones of hematite and clay alteration are closely associated with large late brittle faults (Ash and Riveros, 2001; Oliver, 2006; van Straaten et al., 2013; i.e. Figure 1.4). A proper chemical and crystallinity analysis of white mica at the Gibraltar porphyry is necessary to define the clay mineralogy, but this is not included as part of this study. Although magnetite and "B-veins" are present, the K-feldspar and biotite typically associated with potassic alteration are not observed at Gibraltar mine (Bysouth et al., 1995; Oliver, 2010; van Straaten et al. 2013; 2014). Despite the absence of a diagnostic potassic alteration assemblage that typically defines Cu porphyry deposits, the Gibraltar deposit is unanimously considered a Cu-Mo porphyry system.1.4.4.8 Supergene ZoneSupergene enrichment alteration at Gibraltar, as described by Bysouth et al. (1995) and briefly by Drummond et al. (1976) and van Straaten et al. (2013), has been completely mined out. Recent recognition of anhydrite veinlets at a few hundred metres depth below the surface (van Straaten et al., 2014) is observed in other Cu porphyry deposits as supergene alteration (Sillitoe, 2005). During the Pleistocene, the glacial ice moved southeast from the Cariboo Mountains and overrode the Gibraltar mine area. The close relationship between the shape of the enriched zone and the leached cap and the present day surface indicates that the oxidation and leaching continued after glaciation; however, some of the process may have occurred in the Tertiary (Drummond et al., 1976). After glaciation, an oxidized (barren) limonitic cap and a supergene zone were left intact beneath roughly 61 metres of glacial till. The 30 metre thick limonite zone covers a supergene copper zone of approximately 95 metre thickness, however, supergene mineralization was recorded in drill core at 19depths of 150 metres or more (internal company report, 1960).1.4.5 MineralizationMineralization at the Gibraltar porphyry deposit is identified by both protolith and alteration type. The distribution of mineralization is structurally-controlled by ductile high strain zones and other faults (Oliver, 2008; van Straaten et al., 2013). The main hypogene mineralization consists of chalcopyrite and to a lesser extent molybdenite, and is predominantly spatially associated with veins; however, disseminated sulphides are also described (van Straaten et al., 2013; 2014). Mineralization occurs proximal to zones of chloritization and sericitization (Bysouth et al., 1995). The most common sulphides are pyrite and chalcopyrite, and copper is predominantly vein-hosted as chalcopyrite (Bysouth et al., 1995). Disseminated sulphides are generally not observed and have little effect on Cu ore grade (van Straaten et al., 2014); this contrasts the observations of Bysouth et al. (1995) who state that very fine-grained chalcopyrite, barely visible to the eye, comprises up to 60% of the copper grade. Molybdenum, although restricted to quartz veins that are Cu-sulphide-depleted is strongly spatially correlated to Cu mineralization (Bysouth et al., 1995). Other hypogene related sulphides include sphalerite and bornite. Sphalerite is most common in Gibraltar North and parts of Gibraltar West (Bysouth et al., 1995). Both of these zones also contain elevated silver grades in association with the copper (Bysouth et al., 1995). Bornite occurs with magnetite and chalcopyrite along the low sulphide peripheries of Pollyanna and Sawmill orebodies (Bysouth et al., 1995).Harding (2012) shows that molybdenite mineralization is most common in quartz veins specifically in late ‘D-veins’ (quartz-sericite-pyrite type veins), and less commonly in ‘B-veins’ (QC type veins) (Drummond et al., 1976). This type of mineralization is different from other Cu-Mo porphyry deposits, where B-veins commonly host molybdenite (Gustafson and Hunt, 1975; Sillitoe, 2010). Harding (2012) mentions that molybdenite mineralization is essentially absent from Border phase quartz diorite, and minimal in “ductile strain zones” (tonalite).Supergene enrichment occurs as chalcocite (15-30 m); with lesser amounts of digenite and covellite below a limonite leached cap (Bysouth et al., 1995). Malachite, azurite, and chrysocolla occur near the top of the leach cap, along with native copper as fracture coatings. Minor cuprite and covellite are found throughout the supergene zone. Limonite, goethite, jarosite, and copper manganese oxides (copper wad) are commonly found in fracture coatings within thrust faults, ductile 20high strain zones, and other structures or areas associated with elevated copper grades (van Straaten et al., 2014).1.4.6 Structural GeologyThe geometry, relative timing, and kinematics of most deformation structures were documented by early workers (Drummond et al., 1976; Sutherland Brown, 1974; Bysouth et al., 1995) and more recently by Ash et al., (1999, 2001), Oliver et. al. (2009), and van Straaten et al. (2013). The early workers recognized a sporadically developed magmatic foliation (in this study termed SM) that strikes east-west and dips southward and transitions into a tectonic foliation (in this study termed S1). Sutherland Brown, 1974; S2 of Drummond et al., 1976). The tectonic foliation (S1) dips gently to moderately to the southwest and is defined by discrete chlorite and/or sericite folia (mica after chlorite; Ash and Riveros, 2001) and strained quartz porphyroclasts. S1 is heterogeneously developed, ranging from absent to very well-developed and is locally oriented parallel to sub-parallel to sheeted quartz veins (Sutherland Brown, 1974; Drummond et al., 1976; Bysouth et al., 1995; Ash and Riveros, 2001; Oliver, 2009). S1 is best developed in proximity to high strain zones and ranges from phyllonitic, to schistose to gneissic in texture (Drummond, 1973; Ash and Riveros, 2001; van Straaten et al. 2013). A second foliation, a crenulation cleavage, was described by Drummond et al. (1976) and was observed in the most highly strained rocks (Sutherland Brown, 1974; Drummond et al., 1976; Ash and Riveros, 2001; van Straaten et al., 2013). This ubiquitously distributed S2 crenulation cleavage (S3 of Sutherland Brown, 1974; and Drummond et al., 1976) is suggested to trend parallel to dilation veins (V4 of Sutherland Brown, 1974; ‘Stage 4’ veins of Drummond et al., 1976) that are steeply to moderately dipping towards the east; however, these relationships are not observed in this study as discussed in Chapter 2. van Straaten et al. (2014) mention that ductile high strain zones contain S2, however, these observations were conducted through unoriented drill core logging methods. These dilation veins are filled with quartz gangue and typically dip shallowly towards the east, parallel to fold axes of folded ‘V1’ veins and ‘S2’ foliation of Sutherland Brown (1974) and Drummond et al. (1976). These locally planar dilation veins contain large irregular sulphide blebs, and are interpreted to have been remobilized (van Straaten et al., 2014), but chalcopyrite is constricted to the ore zone (Drummond et al., 1976).21Leucocratic ‘quartz porphyry’ dikes are generally concordant to the foliation (e.g., Granite Lake pit; Oliver, 2008), however, discordant relationships are also documented (Bysouth et al., 1995), notably in the Pollyanna pit (Ash and Riveros, 2001). Panteleyev (1978) described sinuous sub-horizontal shear zones (strongly foliated rocks) that follow quartz diorite/leucocratic quartz diorite contact. Ash and Riveros (2001) recognized early ‘sub-horizontal’ shear zones or zones of high strain that are laterally discontinuous and deform S1. Ductile thrust faults (zones of high strain), with a top-to-the-northeast sense of shear were mapped by Bysouth et al. (1995), Oliver (2006) and Oliver et al. (2009) in all pits. There are two main thrust fault strands in the Granite Lake pit that strike E-W, and bound the E-W striking package of ore (Figure 1.4), and they are termed the Granite Lake Faults (GLFs). The GLFs are part of the Granite Creek Fault system that is persistent throughout the pits (e.g., Bysouth et al., 1995; Oliver, 2006). The Granite Creek faults are suspected to displace mineralization by thousands of metres (e.g., van Straaten et al., 2013; Oliver, 2006). The orebody in Gibraltar West and Gibraltar North are contained within a similar ductile high strain zone, the Sunset Fault system that dips 35 to 45 towards the south and a conjugate set (Reverse Sunset Fault) that dips 50 to 60 northerly (Drummond et al., 1976; Bysouth et al., 1995; Ash and Riveros, 2001; Oliver, 2009). Oliver (2009) proposes that these shear zones formed synchronously with porphyry emplacement, but Oliver (2006) also noted the stacking of the Granite Lake orebody and the Pollyanna orebody by the Granite Fault suggests early, post-mineralization faulting. Ash and Riveros (2001) describe two parallel sub-vertical shear zones that control the copper ore distribution in the Granite Lake pit. Brittle-ductile, more discrete (thinner) southwest dipping thrust faults, also with top-to NE shear sense, are interpreted to have formed during cooling of the pluton/and or exhumation of the pluton after ductile shearing (van Straaten et al., 2013). Oliver et al. (2009) suggest that the earliest tectonic foliation and the ductile high strain zones formed during emplacement of the batholith and therefore exert a fundamental control on mineralization and alteration.The orebody, and the Granite Creek and Sunset Fault systems, are offset by high-angle, NNW- to NE-striking oblique-slip fault zones (i.e., the North Faults (NF), Pollyanna Fault/East Boundary Fault, Saddle Fault, Connector Fault, etc.; Bysouth et al., 1995; Oliver, 2006). The NNW- to NE-trending oblique-slip faults typically contain Fe-oxidation, clay-rich gouge (Ash and Riveros, 2001), and have up 22to 300 m of displacement (Drummond et al., 1976). These faults have similar kinematics as regional Late Cretaceous to Tertiary dextral strike-slip faults such as the Fraser River fault system and the Pinchi fault system, and its southeastern extension, the Quesnel River fault (Campbell, 2013; in-house report by BGC Engineering Inc.; van Straaten et al., 2013). Similarly, large pit-scale NE- to E-W striking low-angle faults offset the orebody; however, their kinematics are not understood and their relationship with the NNE- to NW-trending strike-slip faults is unknown.  Early workers proposed that emplacement of the GMB occurred syntectonically such that batholith emplacement, deformation, metamorphism and mineralization were a continuous process (Sutherland Brown, 1974; Drummond et al. 1976; and Bysouth et al. 1995). Bysouth et al. (1995) presented a model where deformation of the batholith, including the formation of a penetrative foliation and the ductile shear zones (generally thrust faults) was related to the accretion of Cache Creek terrane to Quesnel terrane, and was initiated before ore deposition, but continued after the metals were deposited, creating the present foliated nature of the ore, alteration and host rock (Bysouth et al. 1995). In contrast, Ash et al. (1999a, b) suggested that the ductile shear zones within the Gibraltar deposit formed during faulting of the batholith against Cache Creek terrane, implying that either mineralization post-dates intrusion or that ore was remobilized into the shear zones. However, Late Triassic Re-Os ages on molybdenum overlap the age of the host tonalite, indicating that intrusion and mineralization are genetically linked (Harding, 2012). van Straaten et al. (2013) argued that because ductile deformation zones contain abundant, folded, sheared and transposed hydrothermal mineralization-stage veins and veinlets, mineralization occurred either before or during deformation. Previous workers (Sutherland Brown, 1974; Drummond et al., 1976; Oliver, 2009; and van Straaten et al., 2013) recognized the importance and relationship between the mineralized veins and the structural history. One of the aims of this study is to determine the relative age of deformation and mineralization.1.4.7 Mine Exploration HistoryThe Gibraltar Mine is currently the second largest open pit copper-molybdenum mine in Canada and has been in production from 1972 to 1998 and 2004 to present. The mine has 802 million short tons of sulphide mineral reserves at 0.301% Cu and 0.008% Mo in 2014 (van Straaten et al., 2013). Copper mineralization was discovered as early as 1917, as reported in the Annual Report of 23Table 1.2 Summary table of mineral showings within the Granite Mountain batholith. Data is summarized from Schiarizza (2015). Gibraltar mine’s 4 open pits including Gibraltar East (093B 012), Granite Lake (093B 013), Pollyanna (093B 006), Gibraltar West (093B 007) and, an adjacent orebody Gibraltar North (093B 011) is yet to be exploited, are not included in the table. The 4 main pits will be discussed to varying degrees in this study.Name Location MINFILE Commodities Minerals Mineralization StyleHost Rock Structure Grade GeophysicsBysouth1 5.3 km north of Gibraltar tailings pond093B 061 Cu+Mo Two zones; one with mo and the other with cpy~Granite Mountain phase ~ ~ ~Rick2 1-2 km north of Gibraltar North093B 062 Cu+Zn+Mo cpy ± mo Disseminated, vein-hostedMine Phase tonalite~0.425 g/t Au, 3.43% Cu over 1.6 m; 6.3 g/t Au, 684 ppm Cu over 0.5 m ~Copper King North31.5 km northeast of Mag~Cu cpy Disseminations and stringersSilicified lapilli tuff~13967 ppm Cu in grab samples; spotty mineralization, lacking lateral continuity~Mag4 About 6 km northeast of Pollyanna~ Cu cpy and mag ± ep ± gt skarnqtz-cb veins and qtz-ep-chl-cb-cemented breccia~ ~ ~I.P. anomalyMad5 1.3 km east-northeast of GM occurrence093B 052 Cu cpy~ ~ ~ ~ ~24Name(continued)Location MINFILE Commodities Minerals Mineralization StyleHost Rock Structure Grade GeophysicsGM6 1-1.5 km north-northwest of Keevil zone093B 002 Cu+Mo cpy ± py ± mo and mal ± az ± cuprite ± tenorite ± limonite and chalcocite qtz veins; chalcocite in supergene enrichmentGranite Mountain phase~ ~Chargeability anomaly highlighted in an I.P. surveyKeevil7 East of Gibraltar Mine093B 002 Cu+Mo cpy ± mal ± moDisseminated in sheared tonalite; mal as coatings on joint surfaces; 1 m thick quartz veins host malGranite Mountain phaseNortheast-trending zone hosts ore; 650 m long and 120 m wide~ ~Catalan Copper82 km north of the lake at the head of Big Camp Creek093B 068 Cu+Mo py ± cpy and minor moDisseminations, veinlets and stockworks in the volcanic rocksFoliated andesite (Nicola group), cut by feldspar porphyry and diorite and quartz diorite (likely Burgess Stock)~ ~Linear magnetic anomalyGunn9 1 km east of Granite Lake pit093B 003 Cu+Mo py ± cpy ± chl ± serSheeted veinlets, 1-2 mm wide and spaced 2-6 cm apart*Mine Phase tonalite*Mine Phase tonalite contains weak foliation dipping gently south; south-dipping quartz vein*~ ~25Name(continued)Location MINFILE Commodities Minerals Mineralization StyleHost Rock Structure Grade GeophysicsMcLeese10 Southeastern tip of the Granite Mountain batholith093B 050 Cu cpy ± py ± mal ± azDisseminated along foliation planes, and localally in quartz veins adjacent to gently dipping shearsBorder Phase quartz diorite. Adjacent Cuisson Lake unit also hosts rare mineralized quartz veinsMinerals occur in east-striking vertical fracture zones~I.P. anomalyIron Mountain111-2.5 km east-southeast of the south end of Cuisson Lake 093B 004 Cu hem ± mag ± ep ± gt ± cpx ± cpy ± malOxide-rich skarn lenses (3 cm  to 2 m wide) occur over a strike length of 1500 m Cuisson Lake unit~ ~ ~Sawmill Zone12South margin of Granite Mountain batholith, 1 km east of the south end of Cuisson Lake093B 051 Cu+Mo cpy ± mo ± py ± bnGypsum veins Border Phase quartz diorite, and tonalite similar to Mine Phase tonalite, and quartz porphyryMineralized zone truncated to the west  by a west-dipping fault (Sawmill fault)~ ~1Schiarizza (2015)2 Payne (1999b), Ash et al. (1999a), Dawson (2007), Hodge & Dawson (2008)3 Payne (1999a)4 Bysouth (1985)5 Mark (1973)6 Rydman (1998)7 Armstrong (1968)8 Mirko et al. (2007)9Geology described by Cannon (1968) and Eastwood (1970)10 Meyer (1971a, b)11 Sutherland Brown (1958)12 Bysouth (1990), Bysouth et al. (1995)26the BC Minister of Mines (Sloan, 1918), by Joseph Briand and partners (Bysouth et al., 1995). The discovery zone is located in the southeast end of Gibraltar West orebody at Gibraltar. Porphyry-related mineral showings are summarized in Table 1.2, and are described in detail by Schiarizza (2015). The mineral showings of the main orebodies of Gibraltar mine are described in detail in Chapter 2. Of the six major orebodies at Gibraltar Mine, the Gibraltar West orebody is the only one that contained surface showings of mineralization within copper-hosting quartz veins. Keevil Mines Ltd. was the first major mining company who optioned the Pollyanna and Gibraltar properties in 1962. Gibraltar Mines Ltd. conducted exploration in 1969 under the joint venture partnership of Canex Placer and Duval Corporation who optioned the property. Drilling by Gibraltar Mines Ltd. led to discovery of the Gibraltar East orebody. In 1970 the Granite Lake orebody was discovered under the full ownership of Canex who acquired the interest of Duval. Production began in March 1972. The Sawmill zone was discovered in 1979. The Gibraltar North orebody was discovered in 1990 (Bysouth et al., 1995).In 1996, Westmin Resources Limited acquired total control of the Gibraltar property and in December 1997, Boliden Limited acquired Westmin and production ceased in 1998. Taseko Mines Limited acquired interest in Gibraltar in July 1999, and resumed production in 2004 (Jones, 2011). On March 31, 2010, Taseko established a joint venture of the Gibraltar mine with Cariboo Copper Corporation, splitting the interest 75/25 in favour of Taseko Mines Ltd (van Straaten et al., 2013).1.5  Thesis OrganizationThe data collection for this research focused on the main operational pit at the Gibraltar mine site; the Granite Lake pit, with ancillary data collected from the three other pits (Pollyanna, Gibraltar West, and Gibraltar East; refer to Figure 1.4). Only select cross sections are presented in the main body of the thesis; however, the remaining cross sections are shown in the appendices. Detailed petrographic descriptions are also presented in the appendices.Chapter 2 presents the bulk of the thesis research, including 1) descriptions of lithology, alteration, and mineralization, 2) cross sections of bench walls, highlighting the structural geology, 3) microstructural and petrographic observations, 4) Granite Lake pit cross sections, 5) geochronological data and interpretation, and 6) discussion. This chapter will be revised and submitted for journal publication. 27Richard Friedman provided CA-TIMS U-Pb (zircon) geochronological data, including chemistry, analysis and data reduction, and assisted with the interpretation of the data. Janet Gabites provided Ar-Ar geochronologic analysis on the white mica and hornblende samples submitted to the Pacific Centre for Isotopic and Geochemical Research.Chapter 3 states the conclusions of this study and provides recommendations for future work. 28Chapter 2 Structural Geology, Kinematics, and Timing of Deformation at the Gibraltar  porphyry deposit2.1  IntroductionThe Gibraltar Mine is located about 10 km north of McLeese Lake and 65 km north-northeast of Williams Lake, Cariboo Region, British Columbia and within the traditional territories of the Northern Secwepemc te Qelmucw and Tsilhqot’in First Nations (Figure 2.1). The Gibraltar porphyry is a large calc-alkaline Cu-Mo porphyry deposit, hosted by a tonalite of the Late Triassic Granite Mountain batholith (GMB). The porphyry is ductiley deformed, with a heterogeneously developed, pervasive foliation, and several high strain zones. The timing of ductile deformation with respect to pluton emplacement, mineralization, and alteration is not clear. Early workers proposed that pluton emplacement, mineralization, and alteration were synkinematic such that fabric development accompanied emplacement of the pluton (Sutherland Brown, 1974; Drummond et al. 1976; and Bysouth et al. 1995; Oliver, 2009). Others proposed that ductile deformation occurred post emplacement (Ash and Riveros, 2001), although the absolute timing of deformation is not known.Within the GMB, the intensity of foliation development is loosely correlated with intensity of hydrothermal alteration, in particular, with the abundance of phyllosilicate minerals. Ductile thrust faults occur in zones of intense alteration and historically were associated with the highest grades of copper mineralization (Bysouth et al., 1995; Ash and Riveros, 2001; Oliver, 2009; van Straaten et al., 2013). Thus, strain localization can be tied to alteration, implying that alteration occurred either before deformation or during deformation (van Straaten et al., 2013). In this study, structural fabrics and areas of strain localization are described in relation to the alteration assemblages and alteration intensity.Here, I present: 1) an overview of lithology, alteration, and mineralization observed at the Granite Lake (GL), operational pit at Gibraltar mines; 2) cross sections of bench walls illustrating the structural geometry, kinematics, and cross cutting relationships observed in the pit; 3) observation of deformation microstructure and from this deduce the kinematics of deformation, the deformation mechanism(s) that accommodated strain and then place constraints on the temperature attending 29535,000 mE540,000 mE545,000 mE550,000 mE5,830,000 mN5,835,000 mN5,825,000 mN5,805,000 mN5,810,000 mN5,815,000 mN5,820,000 mN560,000 mE565,000 mE555,000 mE52.5kilometers0EvsMPvLTdLTdCTcClJccMPvKgKgClJccClJccMJglmJsMPvlmJsOPsMPvLTdlmJsuTvLTbLTdLTtLTblmJsOPsEvsCTcMPvlmJsOPslmJsLTlMcLeese LakeGranite, granodioriteBasalt, chert, limestone,sandstone, siltstone,serpentinite, gabbroUpper TriassicVolcanic sandstone, breccia,conglomerate; basalt, andesite,limestone, siltstoneNicola GroupCache Creek TerraneCarboniferous-Lower JurassicMJgMiddle JurassicCache Creek ComplexMine phase: tonaliteBorder phase: diorite,quartz dioriteConglomerate, sandstone,siltstone, slateGranite Mountain phase:trondhjemiteBurgess Creek stock:tonalite, diorite, quartzdioriteLTllmJsLower to Middle JurassicLate TriassicQuesnel TerraneGranite Mountain batholithBasaltConglomerate, sandstoneKgTonalite, quartz diorite,granodioriteEvsMPvOPsEoceneMiocene-PleistoceneBasalt, andesite, breccia,conglomerate, sandstoneEarly CretaceousSkarn, chlorite schist,chlorite-sericite-quartz-feldspar schistMetamorphic rocksUncertain age and anityOverlap AssemblageOligocene-PlioceneEvCTclLTtLTdLTbuTvJgClJccOpen pitQuesnel F aultFraser FaultFaultMine siteGib EastGib W estPollyannaGranite LakeFigure 2.1 Regional Geology map of the Granite mountain batholith and Gibraltar mine area (from van Straaten et al. (2014), after Schiarizza, 2014), showing location of pits at Taseko Mines.30deformation. 4) Geochronological results of Ar-Ar (white mica) cooling ages from various structures, as well as an Ar-Ar (hornblende) cooling age for the feldspathic Mine Phase tonalite; and a U-Pb (zircon) age of the ore-hosting Mine Phase tonalite. Pit-scale cross sections are constructed with the aid of Leapfrog® Geo. Based on these data, the objectives of this study are to 1) unravel the geometry and kinematics of deformation that have affected ore distribution, 2) place constraints on the timing of deformation structures, and 3) determine if batholith emplacement and mineralization were synkinematic with the earliest deformation structures or if structural modification of the deposit occurred after emplacement and mineralization.2.2  MethodologyThis study focuses on the GL pit, with ancillary data collected from the Pollyanna and Gibraltar West pits (Figure 2.2). The operational GL pit was selected as the primary focus of this research owing to the accessibility to new and older bench walls for geological mapping, the abundance of recent data in a functional database similar to the current operational system, and the relevance of this research to Taseko Mines Ltd. as an aid to exploration and production. Fifty hand samples and thirty drill core samples (refer to Appendix B for hand and drill core sample data) were collected from selected structures and rock types for oriented thin sections. Thirty-one oriented polished thin sections were used in this study (for thin section data, refer to Appendix C). Thin sections were cut parallel to a lineation (if present) and perpendicular to the main fabric (either S1 or a shear zone fabric). In a few samples, sections were cut in two mutually perpendicular planes in order to identify strike-slip versus dip-slip movement in shear and fault zones.Seven geological strip maps were constructed based on geological mapping of select bench walls of various laterally continuity (Table 2.1; refer to Appendix A for structural field data). Sample localities from these benches are also shown in Figure 2.2. Select drill core was logged to aid in the construction of cross sections. Geological data derived from drill core logging and extracted from drill core logs from GL pit, was input into the three-dimensional visualization and modeling program, Leapfrog® Geo; this program was used extensively to aid in the construction of pit-scale cross sections.The lack of strata in the Mine Phase tonalite makes it difficult to correlate structures across 31550000 UTM E  5817000 UTM NGibraltar EastGibraltar WestPollyannaGranite Lake EastGranite LakeGranite Lake West¯SFNF1NF2NF3PFNF4NF5NF6NF8aNF7NF10NF8bNF8NF9EF 2EF 1F10CFGLFGLFGLFGLFGFGFGFGFGFGFGLFNGFNGFNGFNGFNGFNGFNF8cEast Boundary FaultWarren FaultGLFGLFGLFNF9aGLFGLFGLFGLFDSZ 1Outcrop Sample LocationsStrip Map Locations 1 Kilometre10 ft contours, August 2013Lateral shear sense: dextral,sinistralFault, unknownN-S striking dextral normal faultsFault, reverse (Oliver, 2008) East Faults (EF)Low-angle normal faultsFault, reverse (this study), inferred1 Sample NumberField Mapping and Sample Locations1234567826a26b9 1012 131415161711 1819202122252827 2930a30b32333435363738392340a40b41444342a42b31West Connector Ramp3770-3950’ Bench Wall3770’ Bench Wall3800’ Bench Wall3300’ Bench Wall3350’ Bench Wall3725’ Bench Wall3400’ Bench Wall2950’ Bench WallFigure 2.2 Taseko Mines pits, bench maps, and sample collection locations. Sample numbers 1, 2, 3, etc. corresponds to sample code: NM-13-001, -002, -003, etc.. Fault distribution and type are spatially represented and are a compilation from Bysouth et al. (1995), Oliver (2008), and work from this study.32Table 2.1 Summary of mapped bench walls and associated samples collectedLocation Bench Wall (elevation in ft.)Bench Wall (elevation in m)SamplesGranite Lake West: West Connector Ramp3770-3950 1149.10-1203.96 NM-13-001 to 008, 024-027Granite Lake West 3770 1149.10 NM-13-028 to 031Granite Lake East 3725 1135.38 NM-13-018 to 023Granite Lake East 3300 1005.84 NM-13-032 to 033Granite Lake East 3350 1021.08 NM-13-009 to 017South Granite Lake 3800 1158.28 NM-13-034 to 035Gibraltar West 2950 899.16 NM-13-036 to 039Pollyanna 3870 1179.58 NM-13-040 to 04433pits and within each pit. Oliver (2007, 2008) recognized that alteration zones were structurally stacked and repeated by faults in Gibraltar East. This methodology is adapted and modified in this study, to use hydrothermal alteration assemblages at the Gibraltar deposit loosely as separate ‘units’ to define structures. Field observations indicate that alteration assemblages and groups of assemblages are spatially associated with the intensity of fabric development. Primary and secondary alteration assemblages were assigned to volumes of rock. The assigned primary alteration assemblage is defined to be composed of >50% of any given volume of rock and represents the finite (i.e., cumulative) alteration assemblage observed in the rocks (Figure 2.3D). A secondary alteration type or assemblage is assigned if it comprises at least 30% of any given interval of rock (modified after the methods described by Oliver (2006) and van Straaten et al. (2013; 2014). The alteration codes assigned to any given volume of rock are limited to two stages of alteration, and do not represent the actual paragenesis of porphyry hydrothermal alteration (Figure 2.3A, B, and C). The units in all strip maps are alteration assemblage units, and do not correlate with protolith lithology. The strip maps were constructed to graphically illustrate foliation intensity: the closer spaced the form (strike) lines on the cross sections, the more intense the foliation is developed. Foliation intensity is recorded using the following scheme, in order of increasing intensity: Massive (none); Trace (T); Weak (W); Moderate (M); Strong (S) (refer to Figure 2.3A).2.3  Mine Site Geology2.3.1 LithologyThe Gibraltar Cu-Mo mine is situated geographically in the centre of the Granite Mountain batholith (GMB) (Figure 2.1). The GMB is composed of five different phases that get progressively more felsic toward the north-northeast (e.g., K2O content increases, with a corresponding decrease in MgO content and normative An (%); Bysouth et al., 1995). The intrusive phases, from the southernmost exposure are: 1) Mafic-rich phase, 2) Border Phase quartz diorite, 3) the ore-hosting Mine Phase tonalite, 4) Granite Mountain phase trondhjemite, and 5) the leucocratic tonalite dikes (Figure 2.4). Bysouth et al. (1995) show that GMB compositions are consistent to calc-alkaline “I-type” granitoids related to porphyry deposits (Ishihara, 1981). 2.3.1.1 Mine Phase TonaliteThe Mine Phase tonalite is the most abundant rock type in the Gibraltar mines property and 34255˚250˚ 070˚15.34 m075˚High Medium Low Trace to NonePropyliticQuartz-ChloriteSericiticCumulative AlterationStrong Foliation IntensityTrace-WeakAlteration IntensityModerateABCDBoudinaged quartz-veinTectonic Foliation (S1)AlterationDeutericPropyliticQC QSPQSC/QSLithologyFeldspathic Mine Phasetonalite All other rock isMine phase tonalite Leucocratictonalitic dyke AQIron OxidesCopper OxidesSymbology35Figure 2.3 Alteration paragenesis and representative finite (cumulative) alteration sections. Intensity of alteration is displayed for each event. Intensity is a qualitative measurement based on vein density and matrix alteration for any set volume of rock. Samples collected at the bottom of the benches are used to interpret at higher elevations that were not accessible. A. Initial pre- to early-mineralization stage propylitic alteration. Representative foliation intensities are shown for trace-weak, moderate, and strong tectonic foliation. B. Main-mineralization stage quartz-chlorite alteration overprint. C. Sericitic alteration that is a combination of porphyry-related (phyllic) hydrothermal alteration and partially associated with later regional faulting. D. Cumulative alteration, with structural elements and other features mapped.36is host to the copper-molybdenum mineralization in the GL, Gibraltar East, Gibraltar North, Gibraltar West, and Pollyanna ore zones (refer to Figure 2.4 for a geology map of the Gibraltar mine). Mine Phase tonalite comprises >95% of the rock on the Gibraltar Mine property and is variably altered and deformed. The protolith is commonly difficult to discern where alteration and deformation intensities are strong (i.e., within structures); in such cases the protolith is assumed to be Mine Phase tonalite, unless mafic concentrations are noticeably low. The Mine Phase tonalite is composed of 15-25% quartz, 40-50% saussuritized plagioclase and 25-35% chlorite (after hornblende) and is relatively equigranular with grain sizes ~2-4 mm in diameter (Figure 2.5A, B). Accessory minerals include titanite and rutile. Hornblende is moderately to completely altered to dark green chlorite (Drummond et al, 1976; Bysouth et al, 1995), and variably strained. Fresh hornblende is never observed in thin section. In crossed polars, chlorite retains a green to brownish-green colour and does not display typical bluish-grey birefringence colours meaning that the chlorite is Mg-rich. Bluish-grey birefringence colours diagnostic of Fe-rich chlorite commonly occur within high strain zones. Translucent grey quartz can be slightly smaller in grain size compared to plagioclase and hornblende grains; and variably deformed depending on strain and alteration intensity. Quartz grains display undulose extinction, and contain brittle fractures in zones of low strain (Figure 2.5B). Plagioclase is variably altered to albite-epidote-zoisite and sericite (Bysouth et al., 1995) and Michel-Lévy tests conducted on three samples with well-preserved plagioclase grains yield oligoclase (An17) compositions. Sericite lathes, ≤0.01 mm length, alter from the core outwards, and give a dusted texture with their random orientation. 2.3.1.2 Feldspathic Mine Phase TonaliteFeldspathic Mine Phase tonalite contains equant fine-grained (~0.1 mm) quartz (35-45%), feldspar (45-55%), and hornblende (2-3%) (Figure 2.5C, D; Bysouth et al., 1995). Minor bright pistachio green titanite is also observed (<1%), with trace epidote. Subhedral quartz is relatively undeformed, recording weak undulose extinction. Hornblende and plagioclase grains, like the Mine Phase tonalite, are slightly larger in size, but fresher than those found in the Mine Phase tonalite. Euhedral hornblende is relatively undeformed and may be partially chloritized, but still retains its amphibole petrographic properties. Sulphides are uncommon; however, very minor pyrite occurs after hornblende. Clinozoisite-zoisite is uncommon, but is also associated with hornblende. Plagioclase feldspar contains a weak dusting of sericite alteration, and is relatively undeformed with 37 550000 UTM E  5817000 UTM NGibraltar EastGibraltar WestPollyannaGranite Lake EastGranite LakeGibraltar Mine GeologyGranite Lake West¯Saddle FaultNorth Fault 1North Fault 2Nroth Fault 3Pollyanna FaultNorth Fault 4North Fault 5NF6North Fault 8aNorth Fault 7North Fault 10NF8bNorth Fault 8North Fault 9East Fault 2East Fault 1Fault 10Connector FaultGLFGLFGranite Lake FaultGranite FaultGranite FaultGranite FaultGLFNorth Graben FaultNorth Graben FaultGranite Mountain Phase TrondhjemiteMine Phase TonaliteLeucocratic Tonalite Dike Border Phase Quartz Diorite, Diorite10 ft contours, August 2013QuaternaryLateral shear sense: dextral,sinistralFault, unknownLithological contact: dened,inferred (this study)contact (Oliver, 2008)Feldspathic Mine Phase TonaliteN-S striking dextral normal faultsFault, reverse (Oliver, 2008) East Faults (EF)Low-angle normal faults1 KilometreUnconsolidated glacial and alluvial depositsLate TriassicTrend and plunge of lineation (LSS; slickenlines, mineral)Trend and plunge of crenulation lineation (LI)Strike and dip crenulation cleavage (S2)Trend and plunge of intersection lineation (LI)Strike and dip of shear fabric (S1)Strike and dip of strain fabric in NFs555555555555Trend and plunge of fold axis (F1 and F2)55Strike and dip of magmatic fabric (Sm)55Poles of shear fabric (S1) projected on stereographs Fault, reverse (this study), inferredNorth Fault 8cEast Boundary FaultWarren FaultGLFGLFGLFNF9aGLFGLFGLFGLFDuctile Shear Zone 1Granite Lake Faultn=12n=14n=21n=1526325526520441215626141175 6743633535152122738176146531584481253538228442801618545628155024207525301475538256556481506647045 456555256066885 80805878422325 1815 5742045 1951501451161650 675102548441025139351526421825355574722853456079434045 49805865515144?13 365540322156 101053035?84Figure 2.4 Geological map of the Gibraltar mine area. Map is modified from Oliver (2008), with some elements taken from Bysouth et al. (1995). The mapped elements include field mapping data from selected bench areas, and incorporate cross sectional data constructed from drill core data. Data from Oliver (2008) is adjusted for 2013 pit contours and new data, where applicable. Stereograph projections of S1 tectonic foliation from Gibraltar West, Pollyanna, Granite Lake West and Granite Lake East pits. Stereonet data represents data collected from this study.38qtzqtzhblplag olgDser1 mm1 mmepqtzqtzqtzplaghblBplagserEbarren qtz-veinsericitized plagqtzqtzchloritized hblsericitized plagepACplag (+ep)chl-hbl qtzchl-fsparqtzplag (+ser)1 mmFqtzserplagser39Figure 2.5 Rock types within the Gibraltar mine. A. Weakly foliated Mine Phase tonalite that is propylitically altered, as illustrated by weakly sericitized plagioclase (NM-13-015 collected from Granite Lake pit). B. Photomicrograph of weakly foliated Mine Phase tonalite (NM-13-015) with 2-3 mm wide, strained, subhedral quartz, sericitized euhedral plagioclase partially altered hornblende, and very fine-grained secondary epidote, XPL. C. Feldspathic Mine Phase tonalite that is deuterically altered. Sample NM-13-001 DDH is equigranular, fine-grained, and contains saussuritized plagioclase and relatively fresh hornblende (DDH 2007-098, 44.84 m; Granite Lake West). D. Photomicrograph of deuterically altered feldspathic Mine Phase tonalite showing relatively fresh hornblende and euhedral andesine with thin rims of oligoclase-andesine. E. Coarser than normal leucocratic tonalite dyke crosscut by late barren quartz vein (Granite Lake West, West Connector Ramp). F. Leucocratic tonalite dyke. Quartz clasts exhibit undulose extinction and are partially dynamically recrystallized along margins and interstices, while feldspars are undeformed. The groundmass is composed of fine-grained, dynamically recrystallized quartz. XPL.40well-preserved twins, and euhedral shape. A more Ca-rich variety of plagioclase (An30) forms along the rims of the primary plagioclase (An17) grains (Figure 2.5D); measured with Michel Lévy optical techniques. A second feldspar of unknown composition is anhedral, 0.1-0.15 mm in size (~10%), and commonly contains a faint chlorite coating. This mineral is not observed in any other lithologies and geochemical analysis is required to determine its chemical composition. The feldspathic Mine Phase tonalite is almost exclusively deuterically altered.2.3.1.3 Leucocratic Tonalite DikesLeucocratic tonalite dikes are 1-15 metres wide and intrude all mappable units (porphyritic quartz diorite facies of Eastwood (1970); leucocratic phase of Bysouth et al. (1995); leucocratic quartz porphyry dike of van Straaten et al. (2013)). Equigranular plagioclase (30-35%) and quartz (30-40%) phenocrysts are the main constituents (Figure 2.5E, F). Plagioclase boundaries are abraded and rounded, and strongly altered to sericite (15%), but are relatively undeformed. Undulatory extinction in plagioclase however, is exclusive to leucocratic tonalite dikes.A subset of this dike is fine-grained (<0.1 mm); porphyritic, that is ~10-30 cm thick, but can be up to a metre wide (Figure 2.6C). Quartz (30-40%) and feldspar (60-65%) phenocrysts are relatively equigranular, and chlorite (after mafic minerals) specs are sporadically scattered and very fine-grained. Further analysis is necessary to geochemically distinguish the leucocratic tonalite dikes.2.3.2 Spatial Distribution of Intrusive RocksMine Phase tonalite is the major ore-hosting unit (>95%), and the most common lithology on the Gibraltar Mines property (Figure 2.4; comprising 80-90% of total volume). The boundary between the Mine Phase tonalite and the Border Phase quartz diorite to the south of the mine, trends towards ~100-110 (similar to most lithological contacts). The leucocratic tonalite dikes are generally not mineralized. Larger leucocratic tonalite dikes are normally spaced up to 100-200 m apart, and smaller (≤1 m wide) dikes locally occur several metres apart. Feldspathic Mine Phase tonalite is the least altered rock type on the property, with exposures in south GL pit that trend towards east-southeast, and drill hole intercepts at depth in GL West. The Granite Mountain Phase trondhjemite is not mineralized and not exposed in the Gibraltar Mine open pits, but based on drill core data, it is located below the orebody in the GL pit. Drill core intercepts leucocratic tonalite dikes and Granite Mountain Phase trondhjemite in the footwall of the Granite Lake orebody. In the northeast, the trondhjemite is 41Hankerite wispsADeutericDQuartz-ChloriteFQuartz-SericiteG1 cmQuartz-Sericite-Chlorite Ankerite-QuartzE1 cmQuartz-sericite-pyrite vein cross cuts propyliticCPropylitic veinlets cross cut leucocraticquartz porphyry dikeBchlorite±sericite-seamPB veinletS1Propylitic42Figure 2.6 Drill core samples from Granite Lake pit illustrating alteration assemblages in the Gibraltar porphyry. A. Saussurite-chlorite (deuterically) altered mine phase tonalite (2013-018; 72.82 m; 0.006% Cu, 0.9 ppm Mo), that is massive to very weakly foliated. B. Early propylitic (epidote-chlorite-quartz-pyrite-chalcopyrite) PB veinlet (right) and chlorite ± sericite-seam cut a Mine Phase tonalite, and are oriented oblique to the local foliation. C. PA veinlet cross cuts a leucocratic quartz porphyry dike. Dike is fine-grained and is cut by both QC (above) and P (lower) veins (2013-006; 235.37 m depth; 0.043% Cu, 7.2 ppm Mo). D. Pervasive quartz-chlorite (QC) alteration of mine phase tonalite. Late dolomitic vein cross cuts sample (opaque white). E. Quartz-pyrite vein with sericite (after plagioclase) envelope (QSP vein) overprints propylitically altered, and relatively undeformed mine phase tonalite (ddh 2006-021; 163.28 m). F. Pervasive quartz-sericite (QS) alteration with chalcopyrite mineralization stringers (ddh 2013-024; 1.110% Cu, 120 ppm Mo). G. Strongly foliated mine phase tonalite with chlorite-sericite folia (QSC) and elongate quartz (ddh 2013-008; 101.10 m). H. Leucocratic tonalite dike(?) with sericitic alteration and ankerite wisps (0.036% Cu, 7.3 ppm Mo) (van Straaten et al., 2014).43in contact with the Mine Phase tonalite and this delineates the primary copper ore-waste boundary.2.3.3 Alteration and VeinsThe main hydrothermal alteration assemblages are: 1) propylitic (epidote-chlorite), 2) quartz-chlorite (QC), and 3) quartz-sericite-pyrite (QSP), with an intermediate quartz-sericite-chlorite/quartz-sericite phase between quartz-chlorite and quartz-sericite-pyrite (Figure 2.6; van Straaten et al., 2013). These hydrothermal alteration assemblages are based on the composition of veins, veinlets, and matrices. A full description of the vein type, vein composition, the relative timing of vein emplacement and association with alteration assemblages is listed in Table 2.2. A later, post-hydrothermal alteration assemblage consists of ankerite-quartz (AQ) alteration. Grain size is the only method used in this study to distinguish between hydrothermally-derived white mica from mica forming during fluid flow that accompanied deformations. For example, muscovite is typically coarser grained (≥0.1 mm) in proximity to ductile high strain zones and foliated cataclasites, and a finer-grained sericite is associated with dusting of plagioclase grains.Porphyry-related hydrothermal alteration at Gibraltar is assigned to two main events; chloritization and sericitization (Bysouth et al., 1995); and a minor carbonate event of unknown timing. Sericite alteration typically overprints chlorite alteration. Deuteric, propylitic, and quartz-chlorite alteration are grouped in chloritic alteration, and quartz-sericite-pyrite, quartz-sericite-chlorite/quartz-sericite alteration assemblages are part of the sericitic stage. Deuteric alteration is found in undeformed and very weakly altered rocks. Quartz-sericite (± chlorite) and ankerite-quartz alteration assemblages are strongly associated with enhanced laminar fabrics and structures (i.e., with strain); and quartz-chlorite alteration is typically in proximity to ductile thrust faults. In contrast, propylitic, quartz-chlorite, and quartz-sericite-pyrite alteration may cut undeformed rocks as well. Spatially, alteration in GL pit can be segregated into two main zones; quartz-chlorite in the GL West pit, and sericitic in GL East pit (refer to the alteration map in Figure 2.7; Bysouth et al., 1995; van Straaten et al., 2013). A detailed description of each alteration assemblage is provided below, with all data collected during this study.2.3.3.1 Deuteric Alteration: Albite-Clinozoisite-Epidote-ChloriteDeuteric alteration (Oliver, 2006; Figure 2.6A) results in the weak alteration of plagioclase to albite-clinozoisite-zoisite-epidote (termed saussuritization; Bysouth et al., 1995) and the weak 44Table 2.2 Vein types and their associated alteration assemblages, and temporal relationshipsAlteration AssemblageAlteration Characteristics Vein NameMineral AssemblageVein Shape and Texture Mineralization StageVein AppearanceDeuteric/Sausserite-(Albite-Epidote-Zoisite)-ChloriteNo alteration to pale yellow-green saussuritization of feldspars, chloritized-hbl and presence of epidote veinlets~ ~ ~ Pre-mineralization~Propylitic/Chlorite-EpidoteIncrease in pale yellow-green saussuritization of feldspars, chloritized-hbl, epidote grains and veinlets, and chl-ep veins*Ep; PA, PBEp; Chl + Ep ± Py ± Cpy ± QtzEp: 1 mm wide, bright green coloured planar veinlets, and 4-5 cm wide diffused flooding of sericite. Sheeted PA veinlets: thin (1-2 mm), diffuse Ser-Chl envelopes (1-40 mm); may contain cubic Py in the centre ± Cpy; PB: thin (1-3 mm), planar, Qtz ± Ep ± Py ± Cpy veinletsPre- mineralization and early mineralization   Quartz-Chlorite (QC) Alteration intensity characterized by vein density and ranges from no pervasive matrix alteration to prevalent Qtz and Chl replacement of Fsp*QC Qtz ± Chl ± Mag ± Py ± Cpy ± Mo2-20 mm-wide, grey Qtz-vein with and without a Chl-halo. Sometimes Mag/Chl/Mo/Cpy ± Py aligned in centre. Typically contains sharp boundaries and sometimes stockwork; sometimes disconnected, wavy veinlets with more diffuse Qtz-Chl margins*MainQuartz-Sericite (QS) Qtz-Ser flooding ~ ~ Qtz-Ser flooding and replacement of Chl-Qtz-Fsp alterationLateQuartz-Sericite-Chlorite (QSC)Finely disseminated Ser± pale Chl*±Qtz alteration of matrix.  Euhedral grains of Py are sparse~ ~ No specific vein is closely associated with this alterationLate ~*data modified from van Straaten et al. (2013)Ank, ankerite; Chl, chlorite; chalcopyrite; Ep, epidote; Dol, dolomite; Fsp, feldspar; Hbl, hornblende; Mag, magnetite; Mol, molybdenite; Py, pyrite; Qtz, quartz; QSP, quartz-sericite-pyrite; Ser, sericite45Alteration AssemblageAlteration Characteristics Vein NameMineral AssemblageVein Shape and Texture Mineralization StageVein AppearancePhyllic/Quartz-Sericite-Pyrite (QSP)Occurs in varying intensities. Weak QSP alteration is distinguished by 1-3 cm wide sheeted veins, while stronger QSP alteration is characterized by pervasive replacement of the matrix by Qtz and Ser*  a) QSP Qtz + Ser + Py ± Cpy ± Moa) 1-3 cm wide sheeted grey Qtz-veins, with Ser-Qtz envelopes and cubic Py aligned in the centre. b) 1-200 cm wide milky-white veins, with parallel sheeted Mo-veinlets, host bulk Mo-mineralization (Harding, 2012)Lateb) QSM LateAnkerite-Quartz (AQ) Pale Qtz-Ank alteration commonly associated with high strain zones. Sulphide mineralization may occur with Ser ± Chl folia*~ Ank ± Dol Ank-whisps: 2 mm in size, separated sinuous whisps. Veins were either completely deformed or transposed as they are unidentifiable. Interstitial in-filling and as pressure fringesPost-mineralization~ ~ BQ Qtz + Chl ± Cpy ± Py10 cm-1 m thick, boudinaged Qtz-veins with Chl-knots ± Py ± Cpy blebs, enveloped by Chl/Ser-foliaPost-mineralization~ ~ Barren Qtz Qtz Barren, milky-white planar Qtz- veins with sharp margins crosscut all veinsPost-mineralization~ ~ AQ Ank ± Dol Thin, 1-2 mm in width. Often seen infilling micro-fracturesPost-mineralization*data modified from van Straaten et al. (2013)Ank, ankerite; Chl, chlorite; chalcopyrite; Ep, epidote; Dol, dolomite; Fsp, feldspar; Hbl, hornblende; Mag, magnetite; Mol, molybdenite; Py, pyrite; Qtz, quartz; QSP, quartz-sericite-pyrite; Ser, sericite46????550000 UTM E  5817000 UTM N26325526520441215626141175 6743633535152122738176146531584481253538228442801618545628155024207525301475538256556481506647045 456555256066885 80805878422325 1815 5742045 1951501451161650 675102548441025139351526421825355574722853456079434045 49805865515144?13 365540322156 101053035?84Gibraltar EastGibraltar WestPollyannaGranite Lake WestGranite Lake EastGranite Lake¯Saddle FaultNorth Fault 1North Fault 2North Fault 3Pollyanna Fault North Fault 4North Fault 5North Fault 6North Fault 8aNF7NF10NF8bNorth Fault 8North Fault 9East Fault 2East Fault 1Fault 10Connector FaultGLFGLFGranite Lake FaultGranite Lake FaultGranite FaultGranite FaultGLFNorth Graben FaultNorth Graben FaultNGFNorth Fault 8cEast Boundary FaultWarren FaultGLFGLFGLFNF9a GLFGLFGLFContact (this study): dened, inferred1 Kilometre555555AlterationDeutericPropyliticQC QSPQSC/QSAQIron OxidesCopper OxidesContact (Oliver, 2008)10 ft contours, August 2013Lateral shear sense: dextral,sinistralFault, unknownN-S striking dextral, normal faults Fault, reverse (Oliver, 2008) East Faults (EF)Low-angle normal faultsFault, reverse (this study), inferredStrike and dip of shear fabric (S1)Strike and dip of strain fabric in NFsStrike and dip of magmatic fabric (Sm)Trend and plunge of lineation (LSS; slickenlines, mineral)Trend and plunge of crenulation lineation (LI)Strike and dip crenulation cleavage (S2)Trend and plunge of intersection lineation (LI)55555555Trend and plunge of fold axis (F1 and F2)55Ductile Shear Zone 1Gibraltar Mine Alteration Figure 2.7 Gibraltar mine pit map illustrating the distribution of alteration zones. Assigned alteration assemblages are based on the predominant (>50%) alteration assemblage (Gibraltar East from Oliver; 2007, 2008, 2009). Data for Granite Lake, Pollyanna, and Gibraltar West pits are a compilation of data from Oliver (2007, 2008, 2009) and data collected from this study.  47alteration of hornblende to chlorite. Disseminated cubic pyrite occurs sporadically, and defines the outer pyrite zone, typical of a Cu porphyry deposit (Lowell and Guilbert, 1970). Weak sericite after plagioclase occurs as randomly oriented, very fine-grained (<0.01 mm) lathes that produces a cloudy texture to plagioclase grains (refer to the microphotograph in Figure 2.5D). Secondary albite (An31) forms rims around magmatic plagioclase and some quartz that was exclusively observed in feldspathic Mine Phase tonalite (Figure 2.5D). Clinozoisite-zoisite occurs as clusters typically associated with plagioclase grains. Deuteric alteration is weak, such that mafic minerals (hornblende) and plagioclase grains are well preserved (Figure 2.5C). Deuteric alteration is located mostly on the periphery of the GL pit (Oliver, 2008; Figure 2.7), and is associated with the west-northwest trending feldspathic Mine Phase tonalite in the southern portion of the GL pit (refer to the strip map in Figure 2.12 for deuteric alteration of the host rock). The deuteric alteration mineral assemblage may also be partly a result of regional metamorphism. 2.3.3.2 Chlorite-Epidote (Propylitic) AlterationChlorite-epidote (termed propylitic) alteration is defined by both veinlet and matrix alteration (Figure 2.6B). The transition between deuteric alteration and propylitic alteration is qualitative, and generally determined by the complete alteration of hornblende to chlorite, and partial alteration of plagioclase to sericite in the groundmass; or the presence of P (± Ep) veinlets. These phase changes are variably accompanied by epidote, sericite, titanite, quartz, and clinozoisite/zoisite.  Three different veinlets are associated with propylitic alteration; Ep, PA, and PB veinlets (Table 2.2). Bright green-coloured Ep veinlets are composed of epidote. They are generally barren and cross cut packages of deuterically altered rock. Discrete Ep veinlets are typically <1 mm thick and wider, more diffuse Ep veinlets are up to 5 cm thick. PA veinlets are typically composed of chlorite-quartz-pyrite-veinlets (Figure 2.6C). Quartz and pyrite (and rarely chalcopyrite) are located within the veins with granular epidote lining the margins. Exceptions occur and epidote can be a more dominant mineral in some veinlets. Fragmented chlorite (after hornblende) is commonly aligned with the veinlet, and sometimes is the main constituent of the veinlet. Quartz can also form a halo to the PA veinlets. The veinlets range in size from 1-2 mm 48in width, and contain diffuse chlorite-sericite selvages that range in thickness from 1-4 cm. The PA veinlets give a foliation to the rock that is generally sub-parallel to the main foliation (refer to Figure 2.17C). Chlorite-sericite seams typically also form parallel to foliation, and in some cases may be confused with PA veinlets during mapping.PB veinlets are composed of epidote-quartz-chlorite-pyrite ± chalcopyrite. They are generally thin, 1-3 mm, and planar, and can form in sheeted configuration (refer to the photomicrograph for sample NM-13-015 in Appendix C). They have chlorite-sericite selvages but do not generally contribute to a foliaton. These veinlets are less abundant than the PA veinlets. Propylitic alteration is the most pervasive alteration type found in all pits, and the intensity of alteration increases with increasing vein density towards the centre of the mineralized porphyry (Figure 2.7); similar to most copper porphyry systems (Titley et al., 1986). 2.3.3.3 Quartz-Chlorite (QC) AlterationThe quartz-chlorite (QC) alteration assemblage (Figure 2.6D) hosts the majority of mineralization at the Gibraltar mine. QC alteration is associated with both veinlets and groundmass alteration. The groundmass alteration is defined by dark green chlorite (after hornblende) and smoky grey disseminated quartz and relatively minor sericite after plagioclase (Oliver, 2008; van Straaten et al., 2013).QC veinlets are generally thin (2-20 mm-wide), planar and have sharp boundaries, with (Figure 2.8C, D) or without a chlorite envelope. QC veinlets are sometimes wavy, disconnected, and misshaped. The veinlets are composed of quartz, magnetite, chlorite, molybdenite, chalcopyrite, and pyrite - all minerals except quartz are located in the vein centre as a thin linear feature, no wider than two crystal grain lengths (refer to the photomicrograph for sample NM-13-009 DDH in Appendix C). No two minerals, with the exception of chlorite and sulphides, are observed co-existing in the centre of a QC veinlet. The main foliation increases in intensity in proximity to these QC veinlet margins. Planar QC veinlets have a stockwork configuration (Figure 2.8A), and are also locally folded into gentle-open folds or, in some cases tight folds. QC alteration is most common in GL West pit, the eastern half of GL East pit, and parts of the Gibraltar West pit. QC alteration is generally associated with the main ore zone in GL and Gibraltar 49ACBDDLooking NELooking NEQSP veinlets 50Figure 2.8 Main mineralization occurrences at Gibraltar mine. A. Early mineralization-stage, stockwork chlorite-quartz-pyrite ± chalcopyrite veinlets (QC veinlets) crosscut a propylitically altered mine phase tonalite with variable sericitic overprint; Granite Lake East, 3350’ bench wall. B. Sheeted, and folded QSP and P veinlets crosscut a leucocratic tonalite dike, and are sub-parallel to the main foliation. SG4 Builder`s Pad, 3870`bench wall, Pollyanna pit. C. Two mineralization stage quartz-chalcopyrite veinlets with chlorite halos in stockwork configuration, cut a propylitically altered Mine Phase tonalite; Granite Lake East 3350’ bench wall. Inset of (C) is D. Propylitically altered Mine Phase tonalite is overprinted by quartz-chalcopyrite-chlorite-pyrite (QC) veinlets, and is subsequently sericitized.51West pits (Figure 2.7). QC alteration zones are also associated with strongly deformed rocks, and in GL pit, the large, ore-controlling Granite Lake Faults (GLFs).2.3.3.4 Quartz-Sericite-Pyrite (QSP) AlterationQuartz-sericite-pyrite (QSP) alteration also known as phyllic alteration (Lowell and Guilbert, 1970), consists of two main vein/veinlet types: quartz-sericite-molybdenite (QSM) veins and quartz-sericite-pyrite (QSP) veinlets (Figure 2.6E) at the Gibraltar porphyry (Table 2.2), and contains groundmass alteration. Pervasive, QSP matrix alteration contains silica-flooding, sericitic alteration, and disseminated pyrite and chalcopyrite mineralization. Red hues associated with QSP altered rock observed in meso-scale are attributed to late oxidation of elevated iron sulphide content.QSM veins contain milky-white quartz and sheeted molybdenite veinlets with sericitic halos that range in size with respect to the size of the vein (<1 metre). QSM veins range in thickness from 1-200 cm and are always sub-vertical, striking northwest, and are typically associated with faults (Figure 2.9A). Irregularly shaped sulphide blebs that are mostly composed of chalcopyrite, are interpreted to have remobilized in QSM veins; fractured pyrite blebs with interstitial chalcopyrite are also common. Sheeted molybdenite veinlets in the QSM vein record tight and closed folds. QSM veins are most commonly observed in the Pollyanna pit as strongly deformed veins (refer to QSM veins that cut propylitically altered rock in Pollyanna pit; Figure 2.14C). Sheeted QSP veinlets are composed of grey quartz and cubic pyrite, and contain quartz-sericite envelopes up to 3 cm in width. QSP veinlets are 1-3 cm thick. Cubic pyrite is commonly clustered along the medial line of the veinlet and sericite is altered from plagioclase (refer to the photomicrograph for sample NM-13-007 DDH in Appendix C). QSP veinlets generally cross cut Mine Phase tonalite and leucocratic dikes mapped in the 3870’ bench wall in the Pollyanna pit and in 3400’ bench wall of GL East pit (Figure 2.8B).Both QSM and QSP veins contain pyrite, but since faulting is common along QSM veins, cubic pyrite is preserved better in QSP veinlets. 52Amilky-white qtzsheeted mo-veinletscpy blebsLate QSM veinserBP veinletBQ veinEp veinletcpycpy blebsmilky-whiteqtzcbchl-knotsCazuritemalachiteD53Figure 2.9 Mineralization in large quartz veins (A, B), and secondary enrichment (C, D). A. Quartz-sericite-molybdenite (QSM) vein. Milky-white quartz vein composed of sheeted molybdenite veinlets located in these veins, parallel to vein walls; vein has a sericitic halo. Chalcopyrite blebs are common, pyrite blebs are less common (2013-012; 230.61 m; 0.370% Cu, 299.0 ppm Mo). B. Boudinaged quartz-chlorite + chalcopyrite + ankerite(± dolomite) (BQ) vein; example of a milky-white quartz vein with chlorite-knots (1 mm – 20 cm) semi-massive to massive chalcopyrite and pyrite blebs. Propylitic veinlets and unmineralized Ep veinlets are folded. Foliation in the middle of the sample, is oblique to the folded veinlets. Sample collected from Granite Lake East, 3725’ bench wall, not in situ. C. Malachite and azurite in vuggy quartz of propylitically-deuteric altered mine phase tonalite (152.6’ depth; 0.128% Cu, 7.3 ppm Mo; Connector area). D. Rare visible dendritic copper on a fracture surface, QSP altered mine phase tonalite (184’ depth; 0.204% Cu, 30.5 ppm Mo; Granite Lake West).542.3.3.5 Quartz-Sericite (QS) and Quartz-Sericite-Chlorite (QSC) AlterationQuartz-sericite (QS) and quartz-sericite-chlorite (QSC) alteration assemblages do not contain any veins and are strictly composed of groundmass alteration. QS groundmass alteration is composed of pervasive grey to bluish-grey, fine-grained quartz and white sericite alteration that essentially completely replaces plagioclase and floods the host-rock (Figure 2.6F), and overprints propylitic and QC alteration (refer to the photomicrograph for sample NM-13-007 in Appendix C). QSC alteration is also pervasive (Figure 2.6G), but generally confined to smaller, strongly foliated intervals, compared to QS alteration. Translucent grey to white sericite and dark green to black chlorite alteration are more common than grey quartz alteration, and comprise ~70-80% of the alteration. Despite the dark green to black colour of this alteration assemblage, sericite alteration is the most prominent mineral (refer to the photomicrograph for sample NM-13-021 in Appendix C).Chalcopyrite stringers are commonly associated with both QSC and QS alteration assemblages and are parallel to the local foliation when present. QSC-QS alteration are both intensely deformed and associated with, but not limited to, zones of high strain (i.e., high-angle fault zones and ductile thrust faults). QS and QSC alteration are similarly associated with strongly sericitic zones but vary in concentrations of chlorite, and so, for structural mapping purposes the two are mapped as a single unit although historic data has them logged separately. Outside of faults and ductile shear zones in all pits, QSC-QS alteration is common in GL East, in the footwall of Fault 10 (refer to the alteration map in Figure 2.7).2.3.3.6 Ankerite-Quartz (AQ) AlterationPale, creamy orange coloured ankerite, and white, recrystallized quartz (AQ) alteration assemblage (Figure 2.6H) is generally associated with high strain zones and structures (high-angle faults, ductile thrust faults (Figure 2.7), and QSM and BQ veins; Table 2.2). AQ alteration is composed of groundmass alteration, typically with quartz-folia with sporadically occurring ankerite that occurs as 1) sinuous ankerite-wisps (Oliver, 2006; van Straaten et al., 2013; 2014) that form within the tails of quartz σ-porphyroclasts and 2) within the interstices of recrystallized quartz grains (refer to the photomicrograph for sample NM-13-035 in Appendix C). 55White ankerite (± dolomite) occurs as thin (<1 mm) veinlets with sharp vein boundaries that cross cut all other features (Table 2.2 and Figure 2.6C, H). Ankerite is also observed in veins and veinlets, normally infilling interstices of pyrite and quartz. Ankerite is observed in the necks of boudinaged quartz-folia in N-S striking faults and as pressure fringes in the tails of quartz porphyroclasts in north- to northeast-vergent ductile shear zones.A strong association between AQ alteration and deformation and cross cutting relationships suggests that the occurrence of ankerite is not related to hydrothermal alteration, and is a product of later deformation-induced fluid penetration. The laminar fabric associated with AQ alteration is in fact a product of the intensity of strain associated with the structures. This direct relationship, however, makes AQ alteration a good tool for tracking structures, and for this reason is used as marker like other alteration assemblages. Leucocratic tonalite dikes, northeast vergent ductile thrust faults (GLFs in GL pit), and AQ alteration are commonly associated with each other (Oliver, 2008). 2.3.3.7 Fe-Oxides and Clay AlterationReddish-orange coloured Fe-oxides (goethite ± jarosite ± hematite) replace pyrite typically within zones of clay alteration that are associated with large brittle faults and some high strain zones (Ash and Riveros, 2001; Oliver, 2006; van Straaten et al., 2013; refer to the photomicrograph for sample NM-13-039 in Appendix C). Hematite is also observed as surface fracture coatings associated with propylitic alteration (Oliver, 2006). A proper chemical and crystallinity analysis of white mica grains at the Gibraltar deposit would be required to define the clay mineralogy, but was not included as a part of this study. 2.3.4 MineralizationThe main hypogene sulphide mineralization includes chalcopyrite, pyrite, and to a lesser extent molybdenite. Copper and molybdenum mineralization is spatially associated with veins and veinlets (van Straaten et al., 2013; 2014) that occur close to chloritized and sericitized rock (Bysouth et al., 1995). Chalcopyrite also occurs in some zones of high strain as finer-grained stringers that are parallel to the foliation. Trace amounts of bornite and covellite are described in drill core, normally associated with other sulphides (i.e., chalcopyrite). Disseminated sulphides are generally not observed and have relatively little effect on copper ore grade (refer to van Straaten et al., 2014).56Chalcopyrite is predominantly QC veinlet-hosted, but also common in P veinlets, and least common in QSP veinlets. Chalcopyrite commonly forms in the interstitial space between pyrite grains, associated with mafic minerals and magnetite, when observed. Chalcopyrite in QC veinlet margins is locally associated with chloritized mica and clinozoisite-zoisite after plagioclase. Chalcopyrite forms large blebs in QSM and BQ veins. Weathered chalcopyrite is replaced by chalcocite along its margins. Chalcopyrite is normally irregular and globular in shape, except in zones of high strain such as ductile thrust faults, where lenticular shaped grains form stringers that align parallel to the fabric. Rare, native copper is locally observed along fracture surfaces (Figure 2.9D)Single crystals and polycrystalline aggregates of pyrite occur in different localities at Gibraltar mine. Isolated, cubic pyrite crystals (1-3 mm) are disseminated in mostly deuteric, and propylitic alteration zones. The occurrence of cubic, disseminated pyrite in otherwise barren rock in the periphery of the GL pit represents a pyritic halo typical of Cu porphyry systems (Sillitoe, 2010 and references therein). Cubic pyrite is also strongly associated with QSP veinlets, and to a lesser amount with P veinlets and occur as clusters with hydrothermal quartz. Polycrystalline pyrite commonly occurs in BQ and QSM veins as large (<20 cm) blebs (Figure 2.9A, B). However, sulphide blebs may comprise either chalcopyrite or pyrite. Brittly fractured pyrite blebs contain chalcopyrite that form in the fractures (refer to the photomicrograph for sample NM-13-033 in Appendix C1). The highest concentrations of molybdenite occur in QSM veins as thin (<2 mm thick) sheeted veinlets, and as thin (<1 mm thick) features that align along the centre of QC veinlets. There is a strong spatial correlation between chalcopyrite and molybdenite (refer to graphic log representations of geochemical assay data shown in Appendix E1-E5); however, this is not always visible in hand sample. Therefore, at the pit-scale, Cu mineralization is used to represent the orebody as it is similar spatially to molybdenite mineralization (in GL, and Pollyanna; Bysouth et al., 1995). Molybdenite is very fine-grained (≤0.1 mm) and where present outside of a vein, is typically fragmented and scattered sporadically to help define the tectonic or fault fabric. 2.3.4.1 Cu-oxidesThe copper oxide alteration assemblage is used as a unit to map structures. Supergene mineralization includes chrysocolla, chalcocite, azurite, copper wad (manganese), malachite, and native copper. Secondary enrichment occurs at or near surface; along fracture surfaces and in vuggy 57quartz vein/veinlet voids (Figure 2.9C), and in meso-scale, associated with northeast vergent ductile thrust faults (refer to the Granite Lake West 3770'-3950' ramp strip map in Figure 2.11B, D).2.4  Structural Geology - Field and Microstructural ObservationsThe five pits at Gibraltar Mines display similar deformation features. This study focuses on the Granite Lake (GL) pit which is currently the main operational pit at Gibraltar Mines. Detailed structural sections are provided for four benches mapped in the GL pit (Figure 2.10 to Figure 2.13). Ancillary observations were collected from Pollyanna pit (Figure 2.14), and Gibraltar West pit (refer to Gibraltar West strip map in Appendix A1) for comparative purposes. The GL pit is divided into GL West and GL East (Figure 2.2).The main orebody, ductile shear zones (the two largest in the GL pit are named Granite Lake Faults (GLFs); Oliver, 2007a; 2009; Ash and Riveros, 2001), and alteration zones all generally trend S-SE in GL pit. The exceptions are west of North Fault 8 in the GL West pit, and between Fault 10 and the Pollyanna Fault in the GL East pit where all features strike E-W. N- and NW-striking dextral normal faults offset the orebody, ductile shear zones, and alteration zones in the GL pit. GL West pit and GL East pit are separated by a low-angle normal fault (named Fault 10), that strikes 200 and dips moderately to the WNW (Figure 2.7). Fault 10 demarcates an abrupt change in alteration styles, orientation of the orebody, and orientation of shear zones in the pit (e.g., Bysouth et al., 1995; Ash et al., 1999; Ash and Riveros, 2001; Oliver, 2008). Ductile shear zones with N to NE vergence, are shallowly- to moderately-dipping (ductile thrust faults), and are the dominant structures in all pits. These shear zones are particularly well-developed in Gibraltar East (Figure 2.4; Oliver, 2008). The ductile thrust faults are demonstrably offset by dextral faults ± normal displacement and low-angle normal faults (Oliver, 2007; 2008; Figure 2.4). Low-angle normal faults have a variety of orientations. The main orebody in GL is bounded by two northeast vergent ductile thrust faults termed the GLFs. The GLFs are moderate-angle, reverse, shear zones (i.e. ductile thrust faults), that bound a highly mineralized, thin (20-40 m), panel of rock that constitutes the main orebody (Figure 2.7 and Figure 2.4). These large shear zones are associated with smaller-scale thrust faults of similar orientation. Other major faults in the GL pit include a series of faults that trend north and northwest (i.e. North Faults (NF), Oliver, 2006; 2008), and west-northwest 58Granite Lake West: 3770’ BenchNM-13-028NM-13-029NM-13-030aNM-13-030bNM-13-031a, b, c, dNM-13-027370 m15.24 mNorth Fault 9North Fault 8bNorthFault 8cGranite Lake North Fault 9a15˚6˚1˚145˚/75˚118˚/50˚8˚45˚125˚/25˚?255˚NM-13-008NM-13-025NM-13-026B250˚ 070˚15.24 m420 m348˚/90˚??21˚ 3˚45˚60˚20˚28˚16˚43˚18˚275˚50˚24˚161˚/84˚158˚/90˚350˚/80˚192˚/78˚35˚145˚140˚5˚019˚? ?NM-13-001NM-13-003NM-13-004NM-13-006NM-13-007 NM-13-002NM-13-005075˚Granite Lake West: 3770’ - 3950’ RampNM-13-001Dip-slip (reverse)S2 crenulation cleavageP veinletLineation (slickensides, mineral)S2 crenulation lineationFolded P veinletsBoudinaged Qtz-veinTectonic Foliation (S1)Fault contact and/or subhorizontal structureSample IDSample locationAr-Ar illite locationQSM veinMagmatic Foliation (Sm)S2 crenulation axial surfaceFold AxisAlterationDeutericPropyliticQC QSPQSC/QSLithologyFeldspathic MinePhase tonalite All other rock isMine Phase tonalite Leucocratictonalitic dike Lineation (intersection)AQIron OxidesCopper OxidesDip-slip (normal)Lateral-slipSymbology275˚ 095˚ 330˚ 150˚348˚/90˚344˚/54˚003˚/44˚105˚/35˚204˚/18˚200˚/90˚144˚/18˚185˚/85˚?160˚/75˚150˚/90˚134˚/26˚138˚/42˚?A North Fault 9North Fault 8(Rainbow 8)North Fault 8a(Rainbow 9)Looking towards 010˚?3770’ - 3950’ Ramp3770’ BenchNorth Fault 8b?3450’ Bench255˚275˚38˚9˚ 25˚65˚???190˚/85˚ 150˚/85˚NM-13-026A25˚?BCNorth Fault 8(Rainbow 8)BCFigure 2.10 Granite Lake West bench walls and strip maps. A. Photograph of strip maps from two bench walls mapped in the western half of Granite Lake pit. Large, high-angle, N-S trending oblique-slip faults intersect the strip maps and offset the imbricate ductile thrust faults. Both of the mapped Granite Lake West 3770’-3950’ ramp and 3770’ bench walls are in the footwall of the GLFs and main orebody in the Granite Lake West pit. Benches are 50 feet (15.24 metres) high. Assigned alteration assemblages are based on the predominant (>50%) alteration assemblage. Foliation intensity increases with decreasing space between form (strike) lines. Details of the geology mapped in different pit locations are provided in Figure 2.11 to Figure 2.14.5915˚6˚1˚145˚/75˚118˚/50˚8˚45˚125˚/25˚?255˚NM-13-008NM-13-025NM-13-026ANM-13-026B250˚ 070˚D15.24 m420 m348˚/90˚??21˚ 3˚45˚60˚20˚28˚16˚43˚18˚275˚50˚24˚161˚/84˚158˚/90˚ 350˚/80˚192˚/78˚35˚145˚140˚5˚019˚? ?S1ENM-13-001NM-13-003NM-13-004NM-13-006NM-13-007 NM-13-002NM-13-005075˚CFS1190˚/85˚ 150˚/85˚25˚?North Fault 8(Rainbow 8)A BNorth Fault 8bNorth Fault 8cNorth Fault 9Granite Lake West 3770’-3950’ bench (West Connector Ramp): Looking towards 340˚ and 345˚60Figure 2.11 Granite Lake West 3770’-3950’ ramp (West Connector Ramp) bench wall and strip map. Refer to Figure 2.10 for legend. Refer to Figure 2.2 for bench location. A. Discontinuous sub-horizontal zone of high strain is oblique to an inclined boudinaged quartz (BQ) vein. B. North Fault 9 with a steeply inclined BQ vein in the lower most bench cuts the footwall of the southwest plunging orebody of Granite Lake West. Iron carbonates are concentrated at the boudin-neck contact between the enveloping damage zone and the quartz vein. Elevated chalcopyrite concentrations are located in the quartz boudin contact. North-south trending dextral normal and normal faults (such as North Fault 9) are characterized by damage zones which contain Fe-oxides, and elevated concentrations of white mica and clay minerals. Teal colouring of the surrounding footwall and hanging wall are indicative of copper oxides. C. North-south trending, dextral normal fault with ~2m wide fault core and damage zone. The fault crosscuts and drags S1 foliation, displaying east side-down kinematics. D. Smaller scale thrust fault with the same attitude as the larger pit-scale GLFs. Blue colour represents elevated copper proximal to the fault zone. E. Rainbow 8 fault with west side-down kinematics and foliated cataclasites in the fault zone core. Steeply-inclined boudinaged quartz vein are common in high-angle faults and have shallowly southeast-plunging lineations defined by the boudin necks. F. Folded and highly oxidized north-south trending, dextral normal fault. Fold axes are southeast-plunging and parallel to all other lineations. 61CSouth Granite Lake: 3800’ bench wallA304˚255˚075˚ 124˚15.24 m170 m242˚/60˚Granite Lake South: 3800’ BenchNM-13-035NM-13-034? Looking towards 214˚ BQuartz vein?B62Figure 2.12 South Granite Lake 3800’ bench wall and strip map. Refer to Figure 2.10 for the legend. Refer to Figure 2.2 for bench location. A. Stitched photograph of south Granite Lake 3800’ bench wall, looking south. Bench is located in the bottom right. B. Strip map area outlined in (A). Bench face is parallel to west-northwest trending, sub-horizontal (127/27) ductile shear zone. Enclosed in the shear zone is a boudinaged, more competent, large quartz vein. A west-southwest trending brittle fault (242/60) cuts the bench, and the larger, ductile shear zone. C. The contact of this shear zone is defined by variably foliated, sericite-quartz folia that contain ankerite + dolomite, molybdenite, and minor chlorite. The enveloping fabric is striking 127, with a dip of 27 towards the SSW. 63Grantite Lake East: 3725’ bench wallNM-13-018NM-13-019NM-13-020NM-13-021NM-13-022NM-13-023275˚Granite LakeImbricate 4lower Granite Lake Fault strand340˚310˚ 360˚ 045˚ 225˚180˚160˚130˚095˚360 mGranite Lake East: 3725’ Bench??A?15.24 m115˚/42˚158˚/18˚106˚/78˚125˚/35˚121˚/78˚035˚/61˚105˚/51˚035˚/50˚140˚/51˚222˚/76˚025˚/50˚143˚/76˚16˚16˚6˚19˚ 20˚ 5˚5˚86˚035˚ 21˚140˚120˚48˚120˚68˚100˚/50˚CLooking WestankankcpyLooking EastBCNM-13-022NM-13-021BFigure 2.13 3725’ bench wall and strip map in Granite Lake East. For a legend, refer to Figure 2.10. Refer to Figure 2.2 for bench location. A. Strip map of the ‘U-shaped’ 3725’ bench wall. Several ductile thrusts mapped, and one is inferred to be the lower GLF strand. Deformation and mineralization intensity decrease substantially away from thrusts, where rocks are deuterically altered and contain an Sm. B. Imbricated ductile thrust faults (105/51 and 100/50) comprise the lower GLF strand, and are in proximity to meso-scale shear-bands that are defined by discrete chlorite ± sericite-seams, mineralization-stage veinlets, and S1. These shear-bands infer top-to-the-north-northeast shear sense. C. Elevated, stretched chalcopyrite concentrations and ankerite wisps, commonly associated with Granite Lake Faults, contribute to the S-C fabric in hand sample (sample NM-13-021 collected from the red dot in (A and B)). 64EBNM-13-044NM-13-043BNM-13-043A NM-13-042 NM-13-041 NM-13-040BNM-13-040ANM-13-043B NM-13-043A380 m122˚/21˚088˚/45˚360˚/90˚131˚/81˚090˚/65˚095˚/81˚140˚/14˚136˚/74˚115˚/58˚110˚/22˚ 090˚/22˚15.24 m?338˚/44˚6˚6˚6˚154˚4˚30˚15˚15˚3˚15˚15˚6˚25˚14˚12˚15˚29˚10˚6˚27˚206˚ 026˚ 245˚ 065˚Pollyanna: 3870’ Bench?????????? gougezone098˚/65˚ 120˚/85˚130˚/35˚CLooking towards 296° Looking towards 335°ADD65Figure 2.14 Pollyanna 3870’ bench wall and strip map. Refer to Figure 2.10 for the legend. Refer to Figure 2.2 for bench location. A. Low-angle normal faults contain a boudinaged quartz vein. Foliation in the wall rock is generally concordant, and comprises weak QSP overprinting of propylitically altered Mine Phase tonalite. B. QSP veinlets that are sub-parallel to parallel to S1 foliation, overprint Mine Phase tonalite, and are drag-folded by a low-angle, northeast dipping conjugate fault that contains a QSM vein. C. Strip map of the 3870’ bench wall, highlights a relatively moderately to strongly foliated Mine Phase tonalite, in the northern part of the pit; and less so in the south. One relatively large leucocratic tonalite dike is mapped, that is structurally bound by faults. QSP alteration overprint is strong with the presence of sub-horizontal to shallowly south-southwest dipping QSP veinlets and northwest trending, sub-vertical faults that contain QSM veins that track closed to tight folds, and drag-fold the QSP veinlets. Inset boxes depict photograph locations. D. Imbricate ductile thrust fault displaces Mine Phase tonalite over a leucocratic tonalite dike. E. Leucocratic tonalitic dike (yellow colour) is cross cut by QSP and P veinlets that are sub-parallel to the tectonic foliation, and openly folded with shallowly SE-plunging fold axes. 66trending oblique-slip faults (East Faults (EF), Oliver, 2006; 2008), and normal faults. The structural elements observed in the pits are described below from the interpreted oldest to youngest structural events. Field data was collected with limited access to specific benches, over 10 days in the different pits. Microstructural observations aid in the interpretation of the structures.2.4.1 Magmatic Foliation (Sm)The earliest fabric observed in the porphyry deposit is a sporadically developed magmatic foliation (Sm), defined by aligned but not strained chloritized hornblende (Figure 2.15A). The magmatic foliation is only visible in zones that are weakly altered and deformed (i.e., rocks with deuteric, up to weak propylitic alteration). GL West is highly strained and altered and Sm was not observed there. In the south GL and GL East areas of the pit, the rocks are less deformed and alteration is less intense and hence, the magmatic foliation was preserved. Weathering and oxidation make it difficult to identify Sm in Pollyanna and Gibraltar West pits; and so, very few data was collected in these areas. Only Mine Phase tonalite contains the Sm fabric; Sm is not observed in strongly deformed and altered leucocratic dikes, or in weakly altered and undeformed feldspathic Mine Phase tonalite. Based on limited measurements, Sm strikes approximately east-west and dips gently to the southeast in the GL pit (Figure 2.16A).2.4.2 D1 Structures2.4.2.1 The Main Foliation (S1)The earliest tectonic fabric (S1) is well-developed in deformation panels that are separated by panels of massive to poorly foliated rock. In the areas mapped in GL pit, >95% of all rock contains a foliation. In Pollyanna pit, in the section mapped, almost all mapped rocks were foliated. With respect to the alteration, the strained panels of rock are generally located within QC, QSP, and QSC-QS altered rock. Propylitically altered rock is variably strained and these panels of strained rock are separated by less, to unstrained, deuterically altered rock. The foliation intensity of propylitically altered rock is graphically depicted on pit cross sections and is classified as massive (or no foliation), trace, weak, moderate, or strong foliation intensity that are described below (e.g., Figure 2.15):1) Massive rock contains no observable foliation, and primary grains contain no preferred orientation (Figure 2.15A).671 cmqtzqtzqtzchl-hblS1chlchlserhem1 mmserserepqtzLooking WestS1FLooking WestEA BMassive TraceWeak ModerateStrongFDC1 cmFigure 2.15 Tectonic foliation (S1). Figure illustrates increasing foliation development in the Mine Phase tonalite at Gibraltar mine (A-E). All samples are collected from Granite Lake pit. A. No foliation, or massive; magmatic foliation (Sm). B. Trace foliation. C. Weak foliation. D. Moderately developed S1. E. Strongly developed S1 in deuterically-propylitic altered Mine Phase tonalite (sample NM-13-024 DDH from 288.8’ depth, Granite Lake West; refer to Appendix E4. for drill core data). F. Photomicrograph from inset of (E) shows S1 defined by elongate quartz and chloritized hornblende. Quartz porphyroclasts are partially dynamically recrystallized with bulging (BLG) recrystallization forms subgrains at grain boundaries. Undulose extinction in quartz is variable, ranging from minimal to pervasive. Hornblende grains are chloritized and strongly strained. Sericite from plagioclase is also aligned with the tectonic fabric, XPL. 68BLSS, n=3LI, n=14 F3, n=7FQSM, n=4Poles to S1, n=15LI, n=4 FQSM, n=8Poles to P veins, n=1F2, n=3 Poles to S1, n=14 (East), n=21 (West)Poles to SM, n=3 (East), n=17 (West)Poles to P veins, n=14 (East), n=12 (West)LSS, n=3 (West)LI, n=12 (West) F3, n=4 (East), n=13 (West)F2, n=4 (East), n=2 (West) AC D NW- to NNE- Trending Dextral Faults ± Normal Displacement (n=22) and Associated LineationsLow-Angle Faults (n=27)and Associated FabricsPoles to S1, n=62F2, n=10FQSM, n=4Structural Elements from PollyannaStructural Elements from Granite Lake69Figure 2.16 Equal-area stereographic projections of structural elements from various pits at the Gibraltar Mine. A. Structural elements from the Pollyanna pit. B. Structural elements from the Granite Lake pit. C. Low-angle faults (ductile thrusts and conjugates, with normal, and reverse kinematics) and associated fabrics, from Granite Lake West (in red); Granite Lake East (in blue); Pollyanna (in orange); and Gibraltar West (in green). D. NW- to NNE-trending, dextral faults ± normal displacement and associated lineations; same colour scheme as (C). Intersection lineations between S1 and cataclastic fault fabric (Li); fold axes (F3); fold axes defined by sheeted molybdenite veinlets within faults with QSM veins (FQSM); fold axes associated with locally open, upright folds of S1 in proximity to low-angle faults (F2); and slickensides and mineral lineations within high-angle faults (LSS).702) Trace foliation is described as having a poor alignment of grains, observed in hand sample (Figure 2.15B).3) Weak foliation is typically defined by aligned hornblende (or chlorite after hornblende), more rarely aligned (but not internally strained) plagioclase, and slightly elongate quartz (Figure 2.15C). Very minor bulging (BLG) recrystallization and weak undulating extinction (<5% of quartz) are observed in quartz.4) Moderate foliation is defined by aligned and elongate quartz and hornblende (Figure 2.15D). BLG recrystallization and undulose extinction of quartz grains becomes more common (~15-20% of grains), sometimes forming deformation bands. Plagioclase is aligned parallel to the foliation.  5) Strong foliation is defined by elongate chloritized hornblende and elongate, flattened, and partially dynamically recrystallized quartz porphyroclasts that typically have an asymmetry showing top-to-the-northeast sense of shear (Figure 2.15D, E). Generally, the flattening component is more prevalent than the non-coaxial shear strain elements, except in the ductile thrust faults. Dynamic recrystallization (~10-20% of porphyroclasts) occurs through bulging nucleation migration (BGM) recrystallization and minor subgrain rotation recrystallization. Undulatory extinction occurs in ~25-30% of quartz porphyroclasts, and commonly is partially recovered to form deformation bands and subgrains. Deformation bands also occur in chloritized hornblende, indicative of intense strain.With increasing strain, the rock becomes compositionally layered and 1-3 mm wide sub-planar chlorite ± sericite-seams are developed (mica after chlorite-lamellae of Ash and Riveros, 2001). The chlorite ± sericite-seams are interpreted to have formed from the accumulation, alignment, and compositional zoning of chloritized primary mafics (Figure 2.17A, C). Plagioclase, when preserved, even in highly strained rocks, is relatively undeformed and albite twinning is unaffected. Increased deformation intensity is normally associated with increased sericitic alteration, where closely spaced sericite and chlorite lamellae help define the foliation (Sutherland Brown, 1974; Drummond et al., 1976; Oliver et al., 2009; van Straaten et al. 2013). Although sericite alteration commonly enhances fabric development, sericite alteration is not always present in highly strained rocks. Rather, chlorite can be the mineral that localizes strain.The S1 foliation is generally shallowly south dipping and locally it is folded. The S1 orientation 71S1CScpy2 cmA 1 mmCqtzcpy Sqtzcbser + qtz matrixchlLooking ESE C DB Looking west 72Figure 2.17 Mylonitic fabrics. A. S-C fabric in a predominantly propylitically altered Mine Phase tonalite with minor sericite alteration, shows dextral shear sense. C-surface is defined by chlorite-epidote-quartz-pyrite-chalcopyrite veinlets, and the S-surface is defined by elongate quartz and inclined chlorite ± sericite; sample collected from Granite Lake West pit. B. Photomicrograph of an s-c fabric indicating dextral shear sense in a sericitic altered Mine Phase tonalite(?) with ankerite wisps, collected from a ductile thrust (inferred as a GLF imbricate) in Granite Lake East. S-surfaces are defined predominantly by elongate quartz, green chlorite (after hornblende), and C-surfaces are commonly defined by ankerite and sericite, PPL, RL. C. Mylonitic fabric associated with a GLF is defined by elongate quartz porphyroclasts and chlorite-sericite folia, dipping towards the south in Granite Lake East. D. Boudinaged quartz (BQ) vein in the bench above the 3870’ bench wall defines an S-surface, in the bench above the 3870’ bench wall mapped in Pollyanna pit.73varies between pits (refer to stereographic data of S1 in each pit in Figure 2.4). S1 in GL pit generally dips SW, however it is gently folded with a shallowly southeast plunging fold axis (F1) (Figure 2.16A, B, C). This warping of S1 is likely caused by a large scale, gentle-open fold (e.g., Sutherland Brown, 1976). In GL West, S1 is shallowly-moderately dipping to the SW, whereas in GL East, S1 is sub-horizontal to shallowly dipping towards the south. S1 in Gibraltar West dips shallow-moderately to the SW (refer to stereograph inset in Figure 2.4). S1 in Pollyanna pit dips SE, and is likely folded at the pit-scale (Figure 2.16B). Variations in the orientation of foliation are attributed to re-orientation by later structures (e.g., folding and faulting).The S1 fabric increases in intensity near ductile thrust faults with north and northeast vergence (Figure 2.13A), where it essentially transitions into a mylonitic fabric within these structures, suggesting that S1 and thrust faults formed progressively during a north-northeast directed stress. The S1 fabric is cross cut by dextral faults ± normal displacement and low-angle normal faults in the Gibraltar porphyry. 2.4.2.2 Veins and Veinlets Spatially Associated With S1The relative timing of vein and veinlet emplacement and foliation (S1) development was investigated to assess the relative timing of deformation and porphyry emplacement. Early to main mineralization-stage veinlets are commonly oriented sub-parallel to S1 (e.g., P veinlets; Figure 2.17A) and less commonly to QC and QSP veinlets), and a cross cutting relationship is not always clear. In massive, unfoliated rocks, only limited orientation data were collected for the P veinlets, which showed a weak SW dipping orientation for the P veinlets (Figure 2.16A); similar to the orientation of S1.One sample shows that S1 (in a sample of Mine Phase tonalite) cross cuts a hydrothermal veinlet. In this sample, S1 is defined by a weak alignment of chlorite and moderately flattened quartz grains. The sample contains a main mineralization-stage, QC veinlet within which, S1 is locally refracted from the matrix across the veinlet (Figure 2.18A, B). The S1 foliation within the veinlet is defined by sericitized plagioclase and strained quartz. The refraction of the S1 foliation across the veinlet was probably caused by the different strengths of the matrix and the vein and indicates that the hydrothermal veinlet was emplaced prior to the formation of the foliation. This cross cutting relationship was likely preserved because the tonalite was not very strained. At higher strains, 74A1 cmcpyqtzplagchlS1BS15 mmBLG serepCcpydolankserchl5 mmD S1 and folded QC veinlet axial surfaceP veinletaxial surfacehigh strain fabricsassociated with cb+serundeformed plagS175Figure 2.18 Cross cutting relationships between S1 and mineralization-stage veinlets. A. QC veinlet (Granite Lake East 3350’bench wall) with magnetite is overprinted by weakly-developed S1. S1 is defined by sericitized plagioclase and elongate quartz porphyroclasts in the vein, and elongate quartz in the background mine phase tonalite. B. Inset box in (A) is a photomicrograph of the QC vein with S1 deflected from a sub-horizontal orientation to a more steeply dipping angle within the vein. Plagioclase is relatively undeformed with minor undulose extinction and no bent twins, XPL. Black triangles with white outlines show the veinlet margin. C. Moderately to strongly-developed S1 deforms a closed, folded, early mineralization-stage veinlet (P veinlet). D. Axial surface of the folded veinlet is parallel to S1 and a discrete shear zone with ankerite + dolomite and quartz eyes, PPL. Black triangles with white outlines in (C) correspond to the location in (D).76the noticeable deflection of the foliation across the vein would likely be destroyed as the fabric and veinlets become transposed. No hydrothermal veinlets cross cut the main foliation (S1) which indicates that all porphyry-related mineralization occurred either during the formation of the foliation (i.e. a syntectonic porphyry intrusion), or, as indicated by the deflected foliation, that hydrothermal mineralization predated deformation. Deformation of veins and veinlets at Gibraltar are summarized in Table 2.3.Stockwork veinlet formation facilitated deformation in the Mine Phase tonalite by allowing strain to partition into areas with high vein density. Strain is localized into areas with high vein density in two ways: 1) sheeted P and QC stockwork veinlets that are oriented oblique to the S1 foliation give rise to “S-C” mylonite geometry (Figure 2.17A). Slickensides on the chlorite surfaces of the P veinlets (C-surface, parallel to shear) attest to slip along the surface. P veinlets are interpolated to have originally had shallow dip orientation, and helped to localize strain by acting as C-surfaces during shortening associated with the development of S1 (the S-surface). Once the foliation was developed (S-surface), the C- and S-surfaces were then kinematically linked in the S-C geometry to accommodate non-coaxial shear strain. 2) Sheeted PA and PB veinlets are common in GL pit (and in Gibraltar East pit), and are locally folded into open folds with SE-trending fold axes (F1 ) that are anticipated for NE-directed thrusting. The axial surface of the folded veinlets is oriented parallel to the main tectonic foliation (S1) suggesting that the folds and foliation formed synchronously, after the emplacement of the veins/veinlets (Figure 2.18C, D). 2.4.2.3 Ductile Thrust FaultsDuctile shear zones, that have thrust kinematics, are here termed ductile thrust faults. They generally occur within zones of very well foliated propylitic, QC, and phyllic alteration. There are two scales of thrust faults: pit-scale (e.g., the Granite Lake Faults - GLFs) and what are here interpreted as kinematically-linked imbricate thrusts. Pit-scale ductile thrust faults are several tens of metres wide, and extend along strike for several hundreds of metres (e.g., van Straaten et al., 2013). Ductile thrusts generally strike SE, and dip shallowly to moderately towards the SW. West of North Fault 8, in GL West, the GLFs strike E-W, and have a relatively steeper dip. Similarly, between Fault 10 and the Pollyanna Fault in GL East, the GLFs strike east, and dip moderately-steeply towards the south. These 77Table 2.3 Summarized chart of Gibraltar veins/veinlets and their intensity of deformationVein Name Alteration AssemblagesDeformation Intensity (1-5); 5=StrongestDeformation Associated with AlterationVein AssemblageDeformationEpPropylitic  (Chlorite-Epidote)1 Undeformed euhedral and equigranular grains; no SPOEp Openly folded veinsP (1-5) Elongate chloritized hbl with SPOChl + Ep ± Py ± Cpy ± Qtz ± CbOpenly folded veins. Mostly sub-parallel, and oblique to foiliation. Subgrains and SGR recrystallization in QtzQCQuartz-Chlorite (QC)(3-5) SPO; Qtz-augens and elongate chloritized HblQtz ± Chl ± Mag ± Py ± Cpy ± MoOpen to tightly folded veins; FA are parallel to discrete zone of shear. Qtz displays SGR recrystallization~ Quartz-Sericite (QS)(4-5) Ser-planar fabric with recrystallized Qtz-augensQtz + Ser ~~ Quartz-Sericite-Chlorite (QSC)5 Ser and Chl-planar fabrics and recrystallized Qtz-augens~ Veins were either completely deformed or transposed as they are unidentifiablea) QSPPhyllic  (Quartz-Sericite-Pyrite)5 Ser-planar fabric Qtz + Ser + Py ± Cpy ± MoOpen to tighty folded; Openly folded QSP veinlet FA parallel to S2. SGR recrystallizaiton of quartzb) QSM Tightly folded, overturned Mo-veinlets with FA parallel to S2. SGR, BLG, and static recrystallization of QtzBQ~5 ~ Qtz + Chl ± Cpy ± PyBoudinaged Qtz-veins, steeply-dipping in oblique-slip faults, and inclined in reverse faults. SGR recrystallization of quartzBarren Qtz~5 ~ Qtz SGR and triple point junctions indicate static recrystallization, and do not appear to be folded in drill coreCb(?)Ankerite-Quartz (AQ)5 Partially recrystallized Qtz-augens and Ank-wisps with a common preferred orientation. Strong planar Ser±Chl-fabricsAnk-wisps Cb pressure fringes of mantled quartz σ-porphyroclast tails or hornblende porphyroclasts give the wispy shape; wisps are sometimes drag-folded with west side-down kinematics. Cb contains Type I and II deformation twinsCb Ankerite-Quartz (AQ) (?)(1-2) ~ Cb (Ank) Carbonate Type I and II deformation twins deformation twinning. Ank, ankerite; Cb, carbonates; Chl, chlorite; chalcopyrite; Ep, epidote; Fsp, feldspar; Hbl, hornblende; Mag, magnetite; Mol, molybdenite; Py, pyrite; Qtz, quartz; QSP, quartz-sericite-pyrite; Ser, sericite; SPO, shape preferred orientation; FA, fold axis78variations in orientation are attributed to movement along N-S striking faults. The ductile thrust faults are known to exert a first-order control on the location of the orebody, such that the ore is typically bound by thrust faults (Sutherland Brown, 1974; Drummond et al., 1976; Bysouth et al., 1995; Ash and Riveros, 2001; Oliver, 2007a, b, 2008, Oliver et al., 2009; van Straaten et al., 2013). Since the large ductile thrust faults host or constrain the orebodies, they are consistently mined out in all of the Gibraltar pits examined in this study, thus making it difficult to examine these structures in the pits (Figure 2.19A). However, several ductile thrust faults were examined in the field and in drill core. These faults and their attributes are tabulated in Table 2.4.The GL orebody is a narrow, tabular (20-40 m thick) zone that is bound by the two GLFs (Figure 2.19B). Outside this fault-bounded ore body, mineralization is low-grade to non-existent (Bysouth et al., 1995; Oliver, 2007; van Straaten et al., 2013). These ductile thrusts were initially mapped by Oliver (2006, 2007, 2008) and Bysouth et al. (1995), and will be referred to as upper and lower GLF ‘strands’.Rocks along the West Connector Ramp and the 3770’ bench wall are located in the footwall of the lower GLF strand. The 3800’ bench wall mapped in south GL pit is located in the hanging wall of the GLF. Both of these zones that were mapped for this study are relatively less deformed than the mined out ore body located between and within the GLFs. The lower GLF strand intersects the 3725’ bench wall that was mapped in GL East (refer to bench map locations in Figure 2.2). The rock in this location is relatively more strongly deformed.The smaller scale imbricate thrusts are commonly observed in all pits. Imbricate thrusts are typically <3 metres thick and dip shallowly (20-25) to moderately (40-55) towards the south and southwest, and north and northeast dipping conjugate thrust faults are common (Figure 2.20A). S1 is ‘dragged’ into thrust faults and this provides good, top-to-the-NE shear sense indicators. Both the hanging wall and footwall are well-foliated, and locally contain S-C fabrics. These fabrics can extend for several metres laterally from the thrusts (Figure 2.17A), indicating that the thrusts are actually large zones of distributed high strain. The foliation generally dips shallowly to the south and southeast (refer to stereographic data for low-angle fault in Figure 2.16C). Several imbricate thrust faults have boudinaged quartz veins in the fault zone core (see below for description of boudinaged quartz veins). Boudinaged quartz veins are associated with ore and therefore, elevated concentrations of 79Granite Lake pit: Looking south3450’3650’North Fault 8a(Rainbow 9)North Fault 8(Rainbow 8)HW of Upper GLF Strand3850’Main orezoneLooking towards 272B GLFAFigure 2.19 Granite Lake Faults of the Granite Lake pit. A. Stitched photographs show a panoramic view of large fault structures in Granite Lake pit. B. 0.3-0.6 total copper percentage (TCu%) interpolant (orange) is confined by two modeled faults (purple) that represent the two strands of the GLF (data borrowed from Taseko Mines Ltd. (2014) to create interpolants; fault models borrowed from Taseko Mines Ltd. (2014)).80Table 2.4 Gibraltar mine D1 structures and their characteristicsStructure Orientation Thickness Cross cutting relationshipsDisplacement Shear Sense Location Hand SampleDeformation EventFinite StrainGranite Lake Faults (GLF)110 (west of 52000 ft E) and 090 (east of 52000 ft E)/45-5515-30 m in the western continuation of the fault. Flattens in the eastern continuation of the fault†Parallel to sub-parallel to S1. Cross cut by N-S trending strike-slip faults3,4Indeterminate Top-to-the-north and northeast†,1,4 Granite Lake ~ D1NE comressionGLFs* 135/50-552,320-25 m2,3,4, and separated by 120-130 m2,3Parallel to sub-parallel to S1. Cross cut by N-S trending strike-slip faults3,4Indeterminate Top-to-the-north and northeast†,1,3,4 GL East NM-13-021(?)D1NE comressionSunset Fault140-160/35-45⁺1 m-wide fault grades into 5 m-wide zone4Parallel to sub-parallel to S1, cross cut by oxidized high-angle brittle faultIndeterminate Reverse, top-to-the-northeast4Gibraltar West,NM-13-037D1NE comressionReverse Sunset Fault (conjugate fault)315/204; steepens to 50-60 dip⁺30 cm - 1 m, 2-3 m-wide damage zone4Conjugate to Sunset Fault and S1Indeterminate Normal, top-to-the-northeast4; and reverse, top-to-the-southwest1 Gibraltar West and Gibraltar NorthNM-13-039D1NE comression†Oliver (2007a; 2007b)‡Oliver (2008)⁺Bysouth et al. (1995)1Microstuctural analysis2Leapfrog® Geo; TCu% orebody interpolant3Cross sectional interpretation4Field observations81Structure Orientation Thickness Cross cutting relationshipsDisplacement Shear Sense Location Hand SampleDeformation EventFinite StrainImbricate ductile thrusts115/40-50, 110-125/20-2545-30 cm-wide gouge, 30 cm - 1 m-wide damage zone4Parallel to sub-parallel to S1. Open, upright folds of S1. Cross cut by N-S strike-slip faults1,3,4Indeterminate Top-to-the-north and northeast1,4All pits NM-13-018, NM-13-026BD1NE compressionLow-angle normal faults 110-122/22 and 315-340/15-451-2 m4 Parallel to sub-parallel to S1. Open, upright folds of S1. Cross cut by N-S strike-slip faults1,4Indeterminate Reverse1 and normal1,4Pollyanna, GL West, Gibraltar West (?) NM-13-040B, NM-13-044D1 and D3NE compression and NE extensionDuctile Shear Zone (DSZ) 1110/20 15-20 m Parallel to sub-parallel to S12,3Indeterminate Indeterminate GL West; in the hanging wall of GLFs~ D1NE compressionDSZ 2 110/30 15-20 m Parallel to sub-parallel to S12,3Indeterminate Indeterminate GL West; in the hanging wall of GLFs~ D1NE compressionNorth Graben Fault (NGF)110/80-85 Indeterminate Indeterminate South side-down >122 m (?)†Likely a normal or extension fault†Contact between Mine phase tonalite and trondhjemite~ D1 and D3NE compression and NE extensionGranite Fault (GF)110/35-45 Indeterminant Indeterminant; possibly most mineralization stacking GL orebody on Pollyanna†762-914 m (?)†Hanging wall north-northeast†Separates Granite Lake and Pollyanna pits~ D1NE compression†Oliver (2007a; 2007b)‡Oliver (2008)⁺Bysouth et al. (1995)1Microstuctural analysis2Leapfrog® Geo; TCu% orebody interpolant3Cross sectional interpretation4Field observations82copper oxides are associated with ductile thrusts (Figure 2.20A, B). Although ductile thrusts control the distribution of ore within the pit, barren ductile shear zones are common (e.g., van Straaten et al., 2013).Depending on the degree of alteration and the intensity of strain, the ductile fault rocks can have a schistose to gneissic texture. Compositional layering in the fault rocks is defined by sericite ± chlorite folia (commonly associated with QSC-QS alteration) and ankerite ‘wisps’ and quartz-rich layers (AQ alteration). The quartz-rich layers typically consists of elongate, flattened, and distended quartz porphyroclasts (“eyes”) and, in conjunction with chlorite ± sericite can give rise to S-C fabrics (Figure 2.20C). Many ductile shear zones have sheared, transposed, and boudinaged veins that never cross cut the zones of high strain (e.g., van Straaten et al., 2013). In the core of the thrust faults, especially smaller imbricate thrusts; there is a discrete detachment that may represent later, lower temperature, brittle reactivation of the structures (e.g., van Straaten et al., 2013). Several thrust faults have contradictory kinematics, which may be the result of fault reactivation with a normal sense of shear. Imbricate thrust faults are generally spaced about 10-20 metres apart in the GL West, GL East, and Pollyanna pits. The imbricate thrusts are known to stack the ore, causing repetitions of ore grade and a minimum displacement of several tens of metres (Oliver, 2006). The metal zonation pattern reported by Bysouth et al. (1995) includes four zones, from east to west: Cu-Mo; Cu; Cu-Zn-Ag; Zn. Presumably the zonation is integral to the Late Triassic porphyry system, thus the ductile thrust faults do not accommodate significant displacement. Strongly, typically very brittley deformed, leucocratic tonalite dikes are spatially associated with ankerite-quartz (AQ) alteration and ductile thrusts at the Gibraltar Cu-Mo porphyry. Both in pit walls and in drill core, tonalite dikes are located parallel to thrust faults, and have AQ alteration. It is likely that the mechanical contrast afforded by the contacts between leucocratic tonalite dikes and the Mine Phase tonalite was used to localize thrust displacement.2.4.2.3.1 Microstructure of Ductile Thrust FaultsMylonites developed in ductile thrust faults (both pit-scale and imbricate thrust faults) typically contain quartz porphyroclasts (20-35%) set in a foliated matrix (60-80%) of chlorite and 83Fig. D1 mmLooking towards 340˚qtzserchl1 cmCLooking towards 340˚A2 mBLooking towards 340˚84Figure 2.20 Imbricate ductile thrust faults from Granite Lake West 3770’-3950’ ramp. Refer to Figure 2.11 for the ramp location. A. Conjugate fault pair adjacent to thrust fault in (B). B. Northeast verging thrust fault associated with elevated copper grades in the fault zone (blue coloured copper oxides). C. Weakly mylonitic fault fabric contains transparent quartz porphyroclasts (s-surfaces) with milky-white very fine-grained quartz tails, and chlorite-sericite folia defining c-surfaces, hand sample collected from the red dot in (B). D. Photomicrograph of sample in (C) shows top-to-the-NE shear sense defined by elongated and dynamically recrystallized quartz porphyroclasts. Folia composed of clays after white mica and chlorite, XPL.85sericite, strained quartz, and variable amounts of ankerite (generally less than 10%). The quartz porphyroclasts are partially dynamically recrystallized (bulge recrystallization), and contain very fine-grained (≤0.1 mm) recrystallized quartz tails. Many of the quartz boudins/clasts may be a result of strained and distended quartz veins and/or veinlets. Vertical flattening is significant, as illustrated by many quartz porphyroclasts and suggests that there was likely a significantly thick column of rock above the thrust fault during shortening (Figure 2.20D). Quartz veins tend to be dynamically recrystallized and many have 120 degree triple junctions, indicating static recovery following deformation.Quartz porphyroclasts commonly form sigma clasts that provide good top-to-the-northeast shear sense indicators (Figure 2.21A). Fe-rich calcite typically forms in the pressure shadows of quartz porphyroclasts the asymmetry of which provides good shear sense indicators. Very fine-grained (≤0.1 to 0.2 mm) mica-fish are common and also provide top-to-the-north-northeast shear sense indicators. Elongate chalcopyrite, when present, with elongate quartz and strained chlorite form “S” surfaces. “C” surfaces are defined by chlorite, sericite and chalcopyrite (Figure 2.17B), and together these fabrics provide a top-to-the-NE sense of shear (Ash and Riveros, 2001; van Straaten et al., 2013). Pyrite has quartz pressure shadows that are oriented parallel to the C-surface of the shear fabric. Deformed chalcopyrite also occurs within porphyroclast tails, which suggests the sulphides were either remobilized into the pressure shadows, or the copper sulphides were re-located through passive remobilization (Raffle, 1998). Undeformed chalcopyrite that occurs within ankerite pressure shadows suggests that chalcopyrite was remobilized during thrusting (Figure 2.21B, C). Undulose extinction, subgrains, and deformation bands are all pervasive in quartz. Dynamically recrystallized quartz is typically very fine-grained (~µm), indicating high stresses during deformation (Passchier and Trouw, 2005). Solution transfer processes are evident by straight boundaries to quartz clasts along cleavage and the pressure shadows. Thus, during thrusting, fluids were certainly present. Plagioclase grains, where preserved, are rarely deformed, showing minor undulose extinction and straight twin boundaries (Figure 2.21D). This sets an upper limit on the temperature of deformation to less than ~450°C - the temperature required to activate dislocation creep and dynamic recrystallization in plagioclase (Pryer, 1993; Ji, 1998a). The formation of mylonites rather than cataclasites in both the pit-scale thrusts (i.e., GLFs), 86B500 μmcpyankLooking westDplagLooking towards 200˚ankqtz500 μmA1 mmBLGcpyqtzchlserrx qtzLooking WestC500 µmLooking towards 200˚cpyankserqtz87Figure 2.21 Ductile thrust fault microstructures; samples NM-13-021 (A and B) and NM-13-022 (C and D). Refer to Figure 2.13 for sample collection sites. Sample NM-13-021 was collected from the footwall of a ductile thrust; and sample NM-13-022 was collected from the hanging wall of a ductile thrust fault, both within the lower GLF strand. A. Sigmoidal quartz porphyroclasts and white mica in sericite-chlorite-quartz altered mine phase tonalite. Dextral shear sense towards the northeast is defined by chalcopyrite located in the wings and pressure shadows of partially dynamically recrystallized quartz porphyroclasts, high RL and XPL. B. Chalcopyrite with straight grain boundaries is oriented sub-parallel to pressure fringes composed of twinned ankerite that are parallel to a northeast vergent ductile thrust fabric, high RL and XPL. C. Coaxial flattening in the vertical direction, with little to none shear in any direction and no indicators of rotation along the Y-Z plane. Ankerite at the bottom of the photo is along the X-Z plane going into the page, XPL. D. Microphotograph BLG recrystallization and undulose extinction of quartz, which form subgrains. Plagioclase twins are not deformed, XPL.88and the imbricate thrust faults indicate that the physical conditions of deformation (e.g., temperature) were similar during the formation of all ductile thrust faults. Because the intensity of S1 increases towards ductile thrust faults, the formation of S1, the GLFs and the imbricate thrust faults are interpreted to represent a progressive deformation that formed under similar physical conditions and stress regime. That the imbricate thrusts can also contain a more brittle demarcation is interpreted to represent either reactivation under a different stress regime; or reactivation during progressive uplift at shallower crustal conditions (see discussion). 2.4.2.3.2 Folds Locally, open, upright, and symmetrical folds of S1 and mineralization-stage veinlets plunge shallowly towards the southeast; the limbs of which are locally dragged by ductile thrust faults and low-angle normal faults. Boudinaged quartz veins of various sizes sometimes form parallel to the axial surfaces of open folds defined by mineralization-stage P veinlets that are oriented oblique to S1 (refer to Figure 2.9B).Similar dilation veins are described by Drummond et al. (1976) and are oriented parallel to the axial planar cleavage of tight folds of early mineralization-stage veinlets.2.4.2.3.3 Boudinaged Quartz (BQ) VeinsBoudinaged quartz (BQ) veins range in orientation and size, and host remobilized ore. BQ veins are observed throughout all pits are located within ductile thrust faults (refer to the centimetre-scale BQ vein in Figure 2.17D), high-angle faults, and are parallel to axial surfaces of open folds defined by mineralization-stage P veinlets. The veins are 1 cm to <2 metres-wide, contain bull quartz, dark green chlorite large knots (up to 15 cm wide) located at the necks of the boudins (Table 2.2), and ankerite, infills fractures near the vein margins. Very fine-grained chlorite occurs throughout the veins. Chalcopyrite and pyrite normally occur as large (<15 cm) sulphide blebs in the necks of BQ veins, and their presence in these veins strongly suggest remobilization of sulphides. S1 foliation (defined by chlorite and sericite) wraps around BQ veins and forms localized zones of high strain. The boudinage precipitation of sulphide, quartz, ankerite, and chlorite remobilization in dilatant zones is interpreted to have occurred during D1. 892.4.3 D2a Structures2.4.3.1 N-S Striking Dextral Faults ± Normal Displacement High-angle dextral fault zones (named North Faults (NF) by Oliver, 2006) strike NW to NNE (termed 'N-S' herein), are steeply dipping, and cross cut all units and D1 structures (refer to stereograph data in Figure 2.16D and mapped data in Figure 2.4; Oliver et al., 2009). These faults and their attributes, and other faults mapped by previous workers, are tabulated in Table 2.5.The N-S striking, dextral fault zones ± normal displacement have damage zones that are up to 5 metres-wide (Figure 2.22A), and a fault zone core, that is typically about 1-2 metres-wide. The fault zone core generally contain BQ veins that range in thickness from 30 cm to 2 metres (Figure 2.22B). BQ veins can be up to 8 metres in length along strike (Figure 2.22C). The necks of the boudins are oriented ~E-W, indicating a north-south extensional direction during their formation (Figure 2.22D). These BQ veins look very similar to BQ veins found in thrust faults, except that they strike ~N-S instead of E-W.Dextral fault ± normal displacement damage zones range from reddish-orange (goethite ± jarosite ± hematite) to pale beige (clay alteration) in colour. The weathering and oxidation alteration of the fault zones strongly contrast the teal and dark grey hues of the footwall and hanging wall blocks in the GL pit. The core of the fault zone is composed of cataclasites that are compositionally layered with quartz-rich (60-70%) and phyllosilicate-rich (20-35%) bands (Figure 2.23A). Porphyry-related hydrothermal veinlets are not present; instead, thin quartz layers, ranging from the width of a quartz grain to a few centimetres-wide are interpreted to be transposed veins (van Straaten et al., 2013). Quartz layers can form small lenticular boudins and contribute to the formation of mica and quartz compositional bands. Phyllosilicates range in size from microns to several millimetres. Their relatively high abundance is attributed to complete alteration and replacement of feldspars, and they may have precipitated from fluid during deformation. Chlorite and sulphides are highly variable in abundance. Well-developed mineral lineations (defined by muscovite and elongate quartz) and slickenlines (LSS) in the cataclasite, plunge shallowly toward the SE (Figure 2.23B; and for orientation data, refer to stereographs in Figure 2.16A, B, D). The shallow plunge of these lineations indicates that there was a relatively minor dip-slip component to the dextral faults ± normal displacement. Fault fabrics from all observed cataclasites are crenulated. The crenulation lineation and intersection 90YXNNW-NNE (strike of fault zone)1 mLooking SouthwestNorth Fault 8a Cσ1σ3σ2DALooking towards 345˚North Fault 8bS1B North Fault 8Looking towards 345˚Figure 2.22 N-S striking, dextral faults ± normal displacement. Refer to Figure 2.11 for the location of (A) and (B); and refer to Figure 2.10 for the location of (C). A. North Fault 8b (161/84) drags and crosscuts S1 showing east side-down displacement. B. North Fault 8 (150/85) contains a boudinaged quartz (BQ) vein, and drag-folds local foliation. Fault fabric defines west side-down shear sense. C. North Fault 8a (341/80) is composed of a quartz vein boudin that is predominantly stretched in the N-S direction. The enveloping fault fabric is vertical (left), sub-horizontal (bottom), and inclined (top right) and strongly foliated. D. Schematic of the geometry of the north-south trending oblique strike-slip faults and the proposed principal stresses that formed the structures displays the dominant E-W flattening observed through field observations and microstructural analyses. Elongation is in the N-S and vertical directions, and most dominant in the former implying a north-south extensional stress regime, parallel to the strike of the NFs. The kinematic plane in this figure is with respect to the N-S strike-slip faults. 91Table 2.5 Gibraltar mine D2 structures and their characteristicsStructure Orientation Thickness Cross cutting relationshipsDisplacement Shear Sense Location Hand SampleDeformation EventFinite StrainNorth Fault (NF) 1005-010/ 80-85Indeterminate Cross cuts S1, GLFs5, and NF 2†Estimated 18 m†Dextral strike-slip; east side-down‡Pollyanna ~ D2NE transpressionNF 2 340/80-85 Indeterminate Cross cuts S1 and GLFs5Not defined Not defined Pollyanna ~ D2N(?) transpressionNF 3 000-020/sub-verticalIndeterminate Cross cuts S1 and GLFs515-31 m† net displacementDextral strike-slip; west side-down (?)‡Pollyanna and GL East~ D2NE transpressionNF 4 000-010/80-90Indeterminate Cross cuts S1 and GLFs5Estimated 15 m†East side-down† Pollyanna and GL East~ D2NE transpressionNF 5 348/80-90 Indeterminate Cross cuts S1, GLFs and orebody~91 m dip-slip†East side-down² GL East ~ D2NE transpressionNF 6 000-018/84 Indeterminate Cross cuts QC alteration2 and S1~213 m strike-slip2; 31 m dip-slip†Dextral strike-slip2; west side-down†Pollyanna and GL West~ D2NE transpressionNF 7 010/80-90 Indeterminate Cross cuts S1 and GLFs515 m dip-slip† East side-down† Pollyanna ~ D2NE transpressionNF 8 (Rainbow 8)Striking 330 (North GL West), striking 345 (GL West); dipping 80-9040.5 cm - 1 m-thick gauge zones, 3 m-wide damage zone4 Cross cuts S1, GLFs, and orebody~15-31 m†/ ~76 m dip-slip2; 350 m is not observed†⁺;West side-down1,2,3,4, and east side-down†4; dextral strike-slip†GL West NM-13-005, NM-13-030B D2N transpression†Oliver (2007a; 2007b)‡Oliver (2008)⁺Bysouth et al. (1995)1Microstuctural analysis2Leapfrog® Geo; TCu% orebody interpolant3Cross section interpretation4Field observations5Crosscuts orebody by association with GLF92Structure Orientation Thickness Cross cutting relationshipsDisplacement Shear Sense Location Hand SampleDeformation EventFinite StrainNF 8a (Rainbow 9)Gouge/fault: 155-174/51-80; fault fabric: 165/49 and 341/5741-2 m-thick gouge; 8-15 m-wide damage zone4Cross cuts S1, GLFs, orebody, QC alteration model15-31 m(?)† and 122-183 m dip-slip2,3Normal dip-slip (west side-down2,3,4, and east side-down†); dextral strike-slip†,3GL West ~ D2N transpressionNF 8b 161/84 3 m-wide damage zone4Cross cuts S1Indeterminate East side-down3,4; dextral strike-slip¹ GL West NM-13-002D2N transpressionNF 8c 350/80 3 m4 Cross cuts S14, Strongly crenulated (S2)Indeterminate Dextral strike-slip4; East side-down1,4Gibraltar East, GL WestNM-13-003D2N transpressionNF 9 170 (north of GLFs)-190(south of GLFs)/85-902 m, damage zone: 10 m4Cross cuts S1 and GLFs5122 m dip-slip3 East side-down3,4, indeterminant lateral movement1GL West NM-13-007D2NE transpressionNF 9a 185/85 Damage zone: 4 m4Cross cuts S14 Indeterminate West side-down4, indeterminate lateral movementGL West NM-13-027D2NE transpressionNF 10 020/80-90 Indeterminate Cross cuts S115 m dip-slip (?)†East side-down† Between Pollyanna and Gibraltar East ~ D2N transpression†Oliver (2007a; 2007b)‡Oliver (2008)⁺Bysouth et al. (1995)1Microstuctural analysis2Leapfrog® Geo; TCu% orebody interpolant3Cross section interpretation4Field observations5Crosscuts orebody by association with GLF93Structure Orientation Thickness Cross cutting relationshipsDisplacement Shear Sense Location Hand SampleDeformation EventFinite StrainSaddle Fault (SF)015/85 Indeterminate Cross cuts S1 and GLFs5Estimated 31-62 m† dip-slipDextral strike-slip; east side-down‡GL East ~ D2NE transpressionPollyanna Fault (PF), southern continuation: East Boundary Fault⁺North of 47000 ft N: 355-000/80-85 W†; south of 47000 ft N: 040/80-85 N†, 175/62 (Campbell, 2013)~62 m† Cross cuts S1 and GLFs183 m apparent strike-slip, 46-61 m dip-slip†Dextral strike-slip; west or northwest side-down†Northern continuation: Pollyanna. Southern continuation: GL East~ D2N(?)-NE transpressionConnector Fault (CF)/Gibraltar East Fault(?)†015-020/80-85 †Indeterminate Cross cuts S1, GLFs, and orebody213 m apparent strike-slip, 46-61 m dip-slip†Sinistral strike-slip; west wall-down†Separating Granite Lake and Pollyanna pits from Gibraltar East~ D2N(?)-NE transpressionGibraltar North Fault⁺000/90(?) Indeterminate Cross cuts the Gibraltar North orebody122 m apparent strike-slip⁺Apparent dextral strike-slipSoutheastern Gibraltar North~ D2NE transpression†Oliver (2007a; 2007b)‡Oliver (2008)⁺Bysouth et al. (1995)1Microstuctural analysis2Leapfrog® Geo; TCu% orebody interpolant3Cross section interpretation4Field observations5Crosscuts orebody by association with GLF94350˚LSSLSS plunges 18˚ towards 160˚LQSMLiF3Looking towards 345˚FSS and Li plunge 25˚ towards 130˚LiDLooking towards 345˚LQSM plunges 15˚ towards 110˚CA B5 cmNorth Fault 8c North Fault 8bNorth Fault 9Map view95Figure 2.23 Fabrics associated with N-S striking, dextral faults ± normal displacement. Refer to Figure 2.11 for the location of (A), (B), and (C). For the location of (D), refer to Figure 2.14. A. Quartz- and phyllosilicate-rich compositional bands in North Fault 8c. White mica is dragged by the fault fabric to define a dextral shear sense. B. Stepped slickenlines and white mica mineral lineations are sub-parallel to the strike of North Fault 8b (160/81), and defined by phyllosilicates that plunge shallowly towards the southeast. C. Crenulations of S1 in North Fault 9 produces fold axes that are sub-parallel to intersection lineations that plunge shallowly to the SE. D. Pencil cleavage produced by the intersection of a steep fault fabric (131/81) and the background S1 foliation, are parallel to quartz mineral lineations.96lineation (LI) plunge shallowly to the SE (Figure 2.23C, D). There are centimetre-scale folds, in the fault zone. The folds are closed to tight in geometry and are inclined to overturned with their fold axes (F2) trending shallowly to the SE (Figure 2.23C). In Pollyanna pit, these F2 folds are defined by folded, sheeted molybdenite veinlets in QSM veins that are found in NW-trending, sub-vertical faults (refer to Figure 2.16B, C, D for the orientation data for F2 (FQSM) axes associated with faults with QSM veins).S1 and mineralization-stage veinlets are dragged into the dextral, normal faults and indicate a component of normal shear that is typically east side-down (Figure 2.22A, B). Displacement amounts along these faults is difficult to ascertain. Based on mostly field observations of ore offset, there is a proposed ≤300 metre lateral and/or vertical displacement on some faults (e.g., Drummond et al., 1976; Bysouth et al., 1995; Oliver, 2006). I estimated displacement along some faults using drill core observations aided by three-dimensional modeling as visual aid (refer to Leapfrog® Geo screenshots of lateral and vertical fault displacements in Appendix G1). Displacement amounts range from ~60 metres to <220 metres (see Table 2.5).2.4.3.2 D2a Microstructures2.4.3.2.1 N-S Striking Dextral Faults ± Normal DisplacementThe core of these faults contain foliated cataclasites that are enriched in relatively large (up to 0.1 mm long, and 0.5 mm thick) muscovite (20-35%) after plagioclase, primary quartz (30-40%), and secondary (25-35%; recrystallized or hydrothermal alteration-related) strained quartz.Kinematic indicators are provided by Riedel shears (Figure 2.24A), drag-folds, of quartz- and muscovite-rich layers, mica-fish, sigmoidal quartz porphyroclasts, and boudinaged quartz veins (Figure 2.24B, C). Most quartz grains have intense undulose extinction. Vein quartz has dynamic recrystallization by subgrain rotation (SGR) recrystallization. Dynamically recrystallized grains in quartz veins meet at triple junctions, which is indicative of grain boundary area reduction (GBAR) and recovery related to static recrystallization. Muscovite and chlorite also have undulose extinction. Chlorite (after hornblende), ankerite, and sulphides, where present, are weakly stretched and rotated into the main fault fabric. Chloritized hornblende has crenulated deformation bands. Molybdenite veinlets are highly folded. Solution transfer processes are evident by the abundance of quartz pressure shadows.97B500 μmMap view341˚AxialSurfaceserqtz BLGR 500 μmA341˚YMap viewBCNorth Fault 8bmowhite micaqtzC100 μmMap view341˚North Fault 898Figure 2.24 Microstructures in dextral strike-slip faults. A. Microphotograph contains a brittle-ductile dextral strike-slip fault fabric defined by muscovite that drags into the fault. Y-shear is parallel to the main fault strike, and R-shears are oblique to the fault trend, XPL. Inset box in (A) is B. Parasitic fold defined by fragmented molybdenite associated with an axial surface (dashed yellow line) that is aligned parallel to the N-S strike of North Fault 8b, high XPL and medium RL. Inset box in (B) is C. Mica-fish indicate dextral strike-slip shear sense parallel to the foliated cataclasite fabric, high XPL and medium RL.992.4.4 D2b Structures 2.4.4.1 Extensional StructuresLarge, normal faults that offset the deposit range in strike direction, and range in dip from ~20 to vertical. These structures are intensely fractured and weathered, commonly associated with large calving walls, strong hematization and clay alteration of damage zones that extend in the hanging wall and footwall for up to 10 metres. These faults and their attributes are tabulated in Table 2.6.In GL pit, Fault 10 (F 10; strikes 200 and dips 44 towards the WNW; Figure 2.25) is a low-angle normal fault that offsets the orebody and GLFs by ~60 metres. This amount of displacement and sense of shear are confirmed by detailed blast hole geochemical data analysis (pers. comm. with van Straaten and Harding); and contradicts the interpretation of reverse kinematics by Campbell (2013; in-house report by BGC Engineering Inc.). Generally, normal displacement on N-S trending dextral, normal faults and low-angle normal faults ranges up to 220 metres; with the exception of the Sawmill Fault (refer to Table 2.5 and Table 2.6). F 10 is significant in GL pit as it not only displaces mineralization, but also separates a strongly chloritic alteration zone in GL West from a heavily sericitic alteration zone in GL East (refer to alteration map in Figure 2.7). This difference in alteration types largely influenced the location of F 10 formation. Some ductile thrust faults contain mesoscopic normal shear sense indicators, i.e. top-down to the SW (Figure 2.26A). Normal displacement kinematics are observed in the field as: 1) shear bands that are defined by phyllosilicates-rich layers (Figure 2.26B), and 2) several metres of displacement on drag-folds of local S1 foliation and mineralization-stage veinlets (refer to the Gibraltar West strip map in Appendix A1). These meso- and hand sample-scale observations are consistently contradicted by microstructures that yield top-up to the NE (top-up to the SW for conjugates) kinematics (Figure 2.26C). The discrete fault surfaces that are typical in the core of ductile thrusts are presumed to have formed during this reactivation event. These relatively brittle textures suggest deformation occurred during exhumation and uplift.2.4.4.2 Shallowly Plunging SE Fabric (S2)Shallowly dipping SE crenulation cleavage (S2) defined by very fine-grained (<0.5 mm) white mica, is always developed in the steeply dipping phyllosilicate-rich dextral, normal faults (Figure 2.27A). The crenulation folds (F2) plunge shallowly to the SE, similar to the orientation of intersection 1005 m Looking southFault 10HematiteFigure 2.25 Extensional fault: Fault 10 (F 10) in Granite Lake pit (200/44) is a low-angle normal fault which displaces the GLFs and the orebody. The damage zones (red colour) are ~15 m wide. F 10 separates alteration style and the geometry of the orebody in Granite Lake pit, 3400’ bench wall. 101Table 2.6 Gibraltar mine extensional structures associated with D2, and their characteristicsStructure Orientation Thickness Cross cutting relationshipsDisplacement Shear Sense Location Hand SampleDeformation EventFinite StrainFault (F) 10 200/44 1 m-thick gouge zones; 15-30 m-wide damage zone3,4Cross cuts ore body, S1, and GLFs; does not appear to crosscut, or be crosscut by NFs (Campbell, 2013)Vertical displacement of 61 m3Normal (west side-down): Blast hole data (personal communication B. van Straaten, 2015)Divides GL East and GL West~ D2NW-SE extensionWarren Fault225/52 (Campbell, 2013)Indeterminate Indeterminate Indeterminate Indeterminate Southeast of GL pit ~ D2NW-SE extensionEast Fault (EF) 1110-115/80-90†1-2 m3 Cross cut S14 Indeterminate Indeterminate GL West ~ D2?EF 2 115-120/80-85†2 m4 Cross cut S13, 4 Indeterminate Southwest side-down3GL West ~ D2?Sawmill Fault165/30, and 170/30 from the Sawmill zone south⁺Indeterminate Cross cuts “Mafic-phase”, Border phase, Sawmill zone orebody, and S1⁺300 m dip-slip⁺Normal; west wall-down⁺Southwest of Gibraltar mine~ D2NE extension?Gibraltar West Fault195/40 Indeterminate Cross cuts northwestern Gib. West pit61 m of dip-slipNorthwest side-downNorthwest Gib. West pit~ D2NW-SE extension†Oliver (2007a; 2007b)‡Oliver (2008)⁺Bysouth et al. (1995)1Microstuctural analysis 2Leapfrog® Geo; TCu% orebody interpolant3Cross sectional interpretation4Field observations102ALooking towards 296˚1 mmXPLLooking towards 296˚serCBC’SLooking towards 296˚ 5 cmB103Figure 2.26 Low-angle imbricate ductile thrust fault shows contradicting kinematic indicators in meso- and micro-scale. Refer to Figure 2.14 for the location. A. Low-angle fault (110/22) with north-northeast vergence cuts propylitically altered Mine Phase tonalite that is weakly overprinted by QSP veins. Hammer for scale. B. Extensional shear bands in the footwall of the fault imply top-down kinematics, bottom left inset box in (A). C. Photomicrograph of a mylonitic fabric with dextral shear sense defined by a σ-type quartz porphyroclast with dynamically recrystallized quartz in the tails implies that the fault contains reverse kinematics. All plagioclase is altered to sericite. Sample collected from red dot in (A), XPL. 104BLooking towards 345˚ 500 μmSGRS2A Looking towards 345˚S1Looking towards 345˚250 μmBLooking towards 345˚1 mmDC DS2S2cpypyhemqtz chl105Figure 2.27 S2. A. Folded, north-south trending high-angle normal fault (NF 8c) with fold axes that plunge 20 towards the southeast; Granite Lake West ramp. B. Red dot in (A) is the location of a photomicrograph of crenulations defined predominantly by white mica, and quartz that form S2, oriented parallel to dynamically recrystallized quartz through subgrain rotation (SGR) recrystallization. Quartz subgrain boundaries form parallel to S2, XPL. C. Red dot in (A) is the location of a photomicrograph of the spatial relationship between S2 and brittle deformation of sulphides, high RL and XPL. D. Inset box in (C) highlights brittle fractures in strongly hematized pyrite and chalcopyrite are aligned sub-parallel to S2, high RL and XPL.106lineations and mineral lineations, and the axial surface is sub-horizontal. One North Fault (NF 8c) is vertically flattened with fold axes and axial surfaces parallel to the crenulations. The crenulation cleavage is similar in orientation to crenulation cleavages found overprinting moderately- to steeply-dipping phyllosilicate-rich layers in the surrounding Nicola Group and Cache Creek complex (Schiarizza, 2015).2.4.4.3 D2b Microstructures2.4.4.3.1 S2The S2 crenulation cleavage is defined by white mica crystallites (<0.5 mm). In addition, euhedral pyrite, long strands of fragmented molybdenite veinlets, and weakly elongate chalcopyrite are brittly fractured with the fracture planes aligned parallel to S2 (Figure 2.27C, D). Recrystallized fine-grained quartz clusters are locally aligned and parallel to the S2 crenulation cleavage (Figure 2.27B). Insertion of a gypsum plate under crossed polars indicates that there is a lattice preferred orientation (LPO) in the dynamically recrystallized quartz. The S2 is likely a pressure solution cleavage with the passive enrichment of pyrite, molybdenite, and chalcopyrite. Chloritized hornblende forms crenulated deformation bands. Dynamically recrystallized grains meet at triple junction, which is indicative of grain boundary area reduction (GBAR) and recovery related to static recrystallization.2.5  Pit-Scale Cross SectionsTo locate the ore distribution at depth and compare to structural and alteration data, drill core data from Granite Lake (GL) pit was extracted from 91 drill core logs provided by Taseko Mines Ltd. (refer to Appendix D for drill core collar data, drill core survey data, and α angles of S1, respectively). This analysis was constrained from field alteration, geology, and structural mapping. The Leapfrog® Geo modeling program was used as a three-dimensional visualization tool that greatly facilitated understanding the shape of the ore horizons and their relationship to nearby structures, which are presented as cross sections through the GL pit. To create these cross sections the following was done:1. Geochemical assay data from drill core was used to construct an orebody interpolant that represents copper mineralization. This was used to: 1) observe spatial relationships with alteration distribution and faults and shear zones, and 2) compare with the geometries of structural elements 107described in this study. 2. The orientation of veins and veinlets was compared with foliation orientations in zones with different alteration types and strain intensities. This was done to determine if there is a genetic relationship between tectonic deformation and porphyry emplacement or if the porphyry was subsequently deformed.This data was integrated and interpretations were made to create a series of cross sections that highlight: 1) structure (foliations and fault/shear zones), 2) the spatial distribution of copper ore, lithology, alteration, and structures within the GL pit, and 3) cross-cutting relationships of structures with the orebody and alteration zones, and their kinematics.2.5.1 Interpolated Orebody and StructuresThe total copper percentage (TCu%) interpolant was constructed to evaluate the shape of the orebody with structures. The TCu% values are used from geochemical assay data of drill core samples (refer to Appendix F1 for a methodology of the TCu% calculations).The TCu% interpolated data produced spheroidal geometric shapes (Figure 2.28A; termed interpolated orebodies), representing ore, given a set number of isosurfaces and drill hole data (Figure 2.28B; refer to Appendix G1 for isosurface data). The shapes of the interpolated orebody are used to loosely infer the direction of compressive stress during deformation. The measured features used for comparison include: 1) elongate quartz that define S1, 2) NE-vergent BQ vein boudins (i.e. ductile shear zones), and 3) relatively large BQ vein boudins in NNE- to NW-trending dextral faults ± normal displacement. The shape of quartz-chlorite (QC) alteration zones, which typically host ore, was compared to the shape of the interpolated orebody. In addition, the QC alteration zones tend to be tabular and localize ductile thrust faults.No structural trend was a priori assigned to the TCu% interpolants and the QC alteration zone. Therefore an anisotropy to the distribution of the ore is assumed.2.5.1.1 ResultsThe orebody interpolants calculated with TCu% data, generally dip S to SW and are flattened parallel to the S1 foliation (Figure 2.28C); however, their long axes are oriented E-W, similar to boudins 108 Looking towards 290Looking down Looking down EF 1 EF 2GLFNF 9NF 8NF 5NF 6EBFNF 8aNF 4F 10DLooking down, 37 plunge, towards 001ab cdefghCBA121 2109Figure 2.28 TCu% interpolated orebody constructed for Granite Lake pit with Leapfrog® Geo. A.  Specific TCu% orebody interpolants are labeled, and used for geometric analysis. Labeled orebody interpolants (a-h) are shown in detail in Appendix G3. Drill hole intervals represent assigned lithocodes, light blue: deuteric; propylitic: light green; QC: dark green; orange: QSP; pink: QSC-QS; bright red: ductile fault (“e”); burgundy: brittle fault: (“z”). B. Interpolated TCu% orebody shells represent four intervals; <0.1 TCu% (pale yellow); 0.1-0.3 TCu% (yellow); 0.3-0.6 TCu% (pale orange); and >0.6 TCu% (bright orange). The two main interpolated orebody domains are represented by 1) SE-trending, with moderate-steep dips (45-60); and 2) E-W trending with moderate dips (40). C. 0.3-0.6 TCu% interpolant ore shell displaying a strong south-southwest dip. D. Fault meshes collected from Taseko Mines Ltd. are labelled, and cut the TCu% interpolated orebody. Note: some of these meshes have been modified; refer to Figure 2.4 for a map of the faults.110of BQ veins within ductile thrust faults. The ~N-S trending, dextral normal faults separate the GL interpolated orebody into two main domains with respect to its orientation (Figure 2.28B; refer to the orientation data for the interpolated orebodies in Appendix G2). The orientation of the interpolated orebodies, from the western portion of the GL pit strikes E-W; SE-trending between NF 8 and F 10, E-W trending between F 10 and NF 5, and SE-trending E of NF 5. E-W trending interpolated orebodies contain moderate dips (45-60), and SE-NW trending interpolated orebodies contain relatively more shallowly dipping (40). This variance in orientation is attributed to clockwise rotation of the Gibraltar porphyry system and D1 structures caused by D2 dextral normal faults and extension faults.The orebody interpolants are generally spherical or tabular in shape. Nevertheless, minor deviations from these shapes occur near faults and are also attributed to the late, D2 related faults (e.g., the East Boundary Fault, and possibly NF 5, offset and rotated a section of the orebody; Figure 2.28D).2.5.2 Vein Orientation Analysis across Zones of Variable Deformation and Alteration  This work was done because if the deformation of the porphyry deposit post-dates emplacement, then the porphyry-related veins and veinlets should be mechanically rotated in highly strained areas.Alpha (α) angle measurements of 227 mineralization-stage veinlets (P, QC, and QSP) and 16 BQ vein orientations in unoriented drill core are compared to local S1 α angle orientations in zones of varying alteration and foliation intensity. These measurements are assumed to be in the same two-dimensional plane and are assumed to be parallel if two orientations contain a difference of <15 degrees. Thus making it difficult to make a complete differentiation between stockwork and sheeted veinlets. Refer to Appendix F2 for a methodology of the vein orientation analysis. 2.5.2.1 ResultsThe majority of BQ veins are parallel to foliation, although this is based on relatively limited data. Mineralization-stage veinlets typically do not occur in unaltered and unfoliated rock with the exception of 3 QC veinlets (Figure 2.29). In zones without alteration, the lack of veinlets is attributed to the fact that alteration is a function of vein density. Thus, vein density increases with alteration 111422242627314113467415423 43 10 7243 252332 35334364392222 2MassiveTraceWeakModerateStrongMassive Trace Weak Moderate StrongFoliation IntensityAlteration Intensity Propylitic veinletQC veinletQSP veinletBQ veinPropylitic veinletQC DiscordantQSP veinletBQ vein33Decreasing vein densityRelatively barren Relatively barren Parallel (<15)Oblique (≥15)Figure 2.29 Graphic representation of mineralization-hosting veins and veinlets parallel (<15) and oblique (≥15) to foliation (α angle) in zones of rock with variable foliation and alteration intensities. The numbers inside the symbols represent multiple data points per symbol. Data collected from drill hole data borrowed from Taseko Mines Ltd..112intensity.In this study, ~68% of main and late mineralization-stage veinlets are parallel (within <15 degrees) to the local tectonic foliation. Oblique veinlets are uncommon in highly strained rocks, similar to field observations. QC veinlets contained the highest ratio (~2.5:1) of parallel to oblique veinlets which contrasts the lowest ratio of ~1.5:1 for propylitic veinlets. QSP veinlets contained a similar ratio of 1.6:1. These values contradict field observations of mostly sheeted QSP and P veinlets, and stockwork QC veinlets and may be due to the constraints mentioned above. 2.5.3 Cross Section Representations of Deformation, Alteration and Mineralization in the Granite Lake pitCross sections were constructed by hand, with pit-scale three-dimensional visualization aid provided by Leapfrog® Geo modeling program. Most ductile shear zones and foliated cataclastic fault zones have been modeled by Taseko Mines Ltd., some of which have been modified by the author of this study, with the addition structures of notable size. This study used detailed downhole geology and geotechnical logs from drill holes logged from 2006-2014, previous data and maps by Oliver (2006, 2007a, b, and 2008) and surficial and bench wall pit mapping by Jim Oliver and data collected for this research. Leapfrog® Geo was used as a tool to visualize the foliation, fault, alteration, and Cu and Mo mineralization. The cross sections provide a pit-scale representation of the alteration zones, rock phases, zones of ductile and brittle deformation, and orebody within the GL pit. Refer to Appendix F3 for a methodology of the cross section construction. 10 cross sections were constructed by hand, and confirmed with Leapfrog® Geo (refer to  for all cross section location data, and Appendix H7 to H10 for hand-drawn cross sections). Each cross section is 91.44 m (300 feet) in thickness, and generally cut the GL pit N-S and E-W. The cross sections intersect a total 62 drill holes across the GL pit. Other drill holes that did not intersect the cross sections, and are in proximity to the cross sections and the 62 drill holes were utilized to make the best interpretation possible. The cross section locations were chosen based on availability of drill holes and their ability to constrain the Granite Lake ore body to the best of means possible (Figure 2.30). 113????550000 UTM E  5817000 UTM NGranite Lake WestGranite Lake EastGranite Lake¯SFNF3PFNF4NF5NF6NF8aNF8bNF8NF9EF 2EF 1F10CFGLFGLFGLFGLFGFGFGFGFGFGFNF8cEast Boundary FaultWarren FaultGLFGLFGLFNF9a GLFGLFGLFContact (this study): dened, inferred1 KilometreAlterationDeutericPropyliticQC QSPQSC/QSAQFe-oxidesCu-oxidesContact (Oliver, 2008)10 ft contours, August 2013Lateral shear sense: dextral,sinistralFault, unknownN-S striking dextral, normal faults Fault, reverse (Oliver, 2008) East Faults (EF)Low-angle normal faultsFault, reverse (this study), inferredDSZ 1Granite Lake Cross SectionsAA’BB’C’CDD’E’EFF’G G’HH’IJ J’I’Figure 2.30 Cross section locations in the Granite Lake pit. Bolded cross section lines represent refined and digitized cross sections.1142013 August Pit Topography? ?????????????GLFGLFF 10GLFGLFNF 8a? 2006-0612006-0652007-1062007-2352010-0062013-0252013-032D D’2013-0292013-0262012-0042011-001D-D’ - Looking West550010 UTM E2400 ft280032003600400044008009001000110012001300700maslAlterationDeutericPropyliticQC QSPQSC/QSAQIron OxidesCopper OxidesLegendEast Faults (EF)N-S dextral normal faults (North Faults; NF)0 0.3 0.5 0.8 1Fault 10 (200°/44°)Shear Zone, fault fabric as dashed lineBrittle Fault Zones 0m 200m0.1-0.3 0.3-0.6Vertical exaggeration: 1xTCu%: AssayTCu%: InterpolantS1 FoliationShear Zone, inferredStructureG-G’Figure 2.31 N-S cross section D-D' through Granite Lake pit identifies structures, TCu% interpolants, and drill holes with TCu% assay data. Refer to map in Figure 2.30 for cross section location. Foliation strike lines, lithology, and structures are interpreted between drill hole data. There is ~60 metres of normal displacement of GLFs on F 10. The GLFs are associated with QC alteration, and are overprinted by strong sericitic alteration in the footwall of F 10. Deuteric and propylitic alteration are typically on the peripheries of the GL pit. An unknown NF is intercepted at depth of drill hole 2013-032. GLF: Granite Lake Fault; NF: North Fault; QC: quartz-chlorite; QSC: quartz-sericite-chlorite; QS: quartz-sericite; QSP: quartz-sericite-pyrite; AQ: ankerite-quartz.1152013 August Pit Topography????????????????24002800320036004000800900100011001200700maslNF5F 10 + NF 4?F 10 + NF 5?2007-2332007-2022010-008 2006-0582013-0262013-0302006-0462007-2382007-240 2007-241E E’E-E’ - Looking West550207 UTM EAlterationDeutericPropyliticQC QSPQSC/QSAQIron OxidesCopper OxidesLegendEast Faults (EF)N-S dextral normal faults (North Faults; NF)0 0.3 0.5 0.8 1Fault 10 (200/44)Shear Zone, fault fabric as dashed lineBrittle Fault Zones 0m 200m0.1-0.3 0.3-0.6Vertical exaggeration: 1xTCu%: AssayTCu%: InterpolantS1 FoliationShear Zone, inferredStructureFeldspathic Mine Phase tonalite: cross section, drill core Leucocratic tonalitic dike: cross section, drill coreGranite Mountain Phase trondhjemite: cross section, drill coreMine Phase tonalite: comprisesall other rockLithologyG-G’2000 ftFigure 2.32 N-S cross section E-E' through Granite Lake pit showing lithology, alteration, structures, TCu% interpolants, and drill holes with true TCu% assays. Refer to map in Figure 2.30 for cross section location. Steeply dipping foliation that intersects the middle section of the 2013-026 drill hole, may indicate the presence of a high-angle fault (i.e. NF). The GLF imbricate strands in the footwall of F 10 are not easily identifiable. The destruction of the GLF is associated with the strong presence of phyllic alteration and the redistribution of micaceous minerals related to the formation of NFs and F 10. The location of these GLFs may be placed roughly at the sharp segregation between 0.1-0.3 and 0.3-0.6 TCu% interpolated zones, based on the spatial relationship between TCu% interpolated zones and GLFs in other cross sections (e.g. Figure 2.31). The drill holes represent: primary alteration assemblage (left), lithology (centre), and interval code (including intervals for brittle (bright red) and ductile (burgundy) structures). Foliation strike lines, alteration, and structures are interpreted between drill hole data (right). GLF: Granite Lake Fault; NF: North Fault; QC: quartz-chlorite; QSC: quartz-sericite-chlorite; QS: quartz-sericite; QSP: quartz-sericite-pyrite; AQ: ankerite-quartz.116l2013 August Pit Topography?? ? ????GLFGLFNF 9 NF 8NF 8a NF 6EF2EF 1?? ??????PF ????NF 3?SF??????DSZ1GLF*GLF*NF 5G G’2014-0232014-0272014-0102007-0972013-0042014-0192013-0182013-0142013-0232013-0072006-0672013-0162013-0082007-2392013-0252007-2402006-059G-G’ - Looking North5917408 UTM N2000 ft2400280032003600400044008009001000110012001300700maslAlterationDeutericPropyliticQC QSPQSC/QSAQIron OxidesCopper OxidesLegendEast Faults (EF) N-S dextral normal faults (North Faults; NF)0 0.3 0.5 0.8 1Fault 10 (200°/44°)Shear Zone, fault fabric as dashed lineBrittle Fault Zones 0m 200m0.1-0.3 0.3-0.6Vertical exaggeration: 1xTCu%: AssayTCu%: InterpolantS1 FoliationShear Zone, inferredStructureA-A’ B-B’ C-C’ D-D’ E-E’ F-F’Figure 2.33 E-W cross section G-G' through Granite lake pit showing alteration, structures, TCu% interpolants, and drill holes with TCU% assays. Foliation strike lines, alteration and structures are interpreted between drill hole data. Refer to map in Figure 2.30 for cross section location. GLF: Granite Lake Fault; NF: North Fault; SF: Saddle Fault: EF: East Fault; QC: quartz-chlorite; QSC: quartz-sericite-chlorite; QS: quartz-sericite; QSP: quartz-sericite-pyrite; AQ: ankerite-quartz; GLFs*: Granite Lake Faults mapped by drill hole intercepts in GL East (refer to cross section F-F' Appendix H14). NFs offset both GLF, QC alteration, and the TCu% interpolated shapes that represent elevated copper mineralization. A lack of drill hole data produces uncertainty in the centre/GL East portion of the pit.117Seven cross sections face towards the west, 0-20 degrees oblique to the earliest and most prominent deformation kinematic plane (X-Z), and the orebody. The obliquity of the drill holes and structural elements are accounted for in all cross sections. N-S cross sections – similar to the strip maps – display increasing foliation intensity with decreasing space between form (strike) lines. Unlike the strip maps, ductile shear zones are denoted with two wavy lines. Refer to Appendix H11 to H14 for the remaining 4 cross sections (A-C, and F) not presented herein.Three cross sections intersect the GL pit lengthwise from east to west and provides the main kinematic plane (Y-Z) for dip-slip movement on NFs and F 10. For visual clarity, foliation data is not included in the E-W cross section. Refer to Appendix H13 and H14 for cross section I-I' and J-J', respectively.2.5.3.1 ResultsN-S cross section D-D' (Figure 2.31) was selected to observe the abrupt contrast with respect to alteration types, structure, and mineralization between the hanging wall (GL West) and the footwall (GL East) of Fault 10. N-S cross section E-E' (Figure 2.32) was selected to show the spatial relationships between lithologies and alteration, structure, and the interpolated orebody since it intercepted the most abundant variety of lithologies. Lastly, any displacement on the GLFs or imbricate ductile thrusts should be evident in these N-S cross sections. The GLFs are distinguishable in GL West and most strongly associated with quartz-chlorite (QC) alteration and the interpolated orebody (refer to cross section D-D'). The strong, texturally destructive sericitic alteration (quartz-sericite-pyrite-chlorite (QSP-QSC-QS)) in GL East makes it difficult to trace the GLFs and the orebody (see cross sections D-D' and E-E'). The spatial relationship between QC alteration, ore mineralization, and the GLFs is utilized to calculate ~60 metres of normal, west side-down displacement on F 10. Therefore, previous interpretations of F 10 as a thrust fault (Campbell, 2013; in-house report by BGC Engineering Inc.) do not align with this study. Displacement on GLFs remains unknown despite the cross sections.There is a strong correlation between ductile shear zones and zones of strong foliation intensity; but high strain intensities are not limited to these zones, and may vary between the GLFs. Steepening of the S1 cleavage by ~10-15 degrees from GL West to GL East is inferred to have been 118caused by F 10 (see cross section D-D’). At the pit-scale, a change in the orientation of S1 is a good indication of cross-cutting structures. The steepening of foliation dictates the presence of high-angle dextral, normal faults (e.g., drill hole 2013-032 at depth in Figure 2.32; and refer to the Saddle Fault (SF) is almost parallel to the F-F’ cross section in Appendix H14 thus affecting the main fabric). In some cases, foliation differences can indicate shear sense on faults (e.g., SW side-down movement on East Fault 2; refer to cross section B-B’ in Appendix H12).Cross section E-E' highlights the more felsic varieties of the GMB. These lithologies are observed on the outer margins of the GL pit with intercepts in the northern and southern sections of the GL pit, and at depth. The feldspathic Mine Phase tonalite was intercepted near the bottom of one of the deeper drill holes (~740 m.a.s.l. elevation). A large felsic intrusive body is observed at depth, as described by Bysouth et al. (1995) and Oliver (2006), and likely represents the barren zone in the hanging wall of the Granite Fault to the north. Leucocratic dikes at depth in the hanging wall of the GLFs share contacts with ductile shear zones, as observed in the field, and noted by Oliver (2008). East-west cross section G-G’ (Figure 2.33) was selected to observe any vertical displacement on normal faults (e.g., NFs) and to track the GLFs and orebody through the entire GL pit.Similar to cross section D-D', the GLFs in the G-G' cross section bound and are spatially associated with QC alteration and interpolated orebody zones. In G-G', the relationship between the GLFs and quartz-sericite ± chlorite (QSC-QS), and ankerite-quartz (AQ) alteration assemblages is apparent. Ankerite-quartz (AQ) alteration associated with ductile thrusts suggests fluid flow during D1. Utilization of the separated interpolated orebody, GLFs, and (mostly) QC alteration zone in the E-W cross section highlights normal, predominantly east side-down shear sense movement along dextral strike-slip faults (Figure 2.33)Since the strip maps represent such small-scales in relation to the cross sections, field control of the cross sections was not made a priority. Nevertheless, the 3725’ bench wall in GL East (refer to Figure 2.13) acts as a field control for the F-F’ cross section (refer to Appendix H14), where the lower GLF* strand is intersected by both sections and indicates a SE trend. The GLFs are suspected in eastern GL East due to their orientation, ductile fabrics, alteration assemblage, and strong association to the interpolated orebody (see cross section G-G'). These structures are termed GLFs*and are also 119shown in cross section F-F' in Appendix H14 (refer to Table 2.4 for all attributes). Two new, shallowly S- to SW-dipping ductile shear zones were identified (Ductile Shear Zone (DSZ) 1 and 2) in the GL pit (DSZ 1 in G-G' (Figure 2.33) and cross section A-A' (refer to Appendix H11). For DSZ 2, refer to cross section B-B' in Appendix H12). These ductile shear zones are not associated with any notable mineralization, but are of considerable size (~15-30 metre thicknesses; refer to Table 2.4 for all attributes). Spatial relationships are shown to provide fault displacement measurements to map orebodies and ductile shear zones, and predict high-angle fault locations. The strong association between crenulation cleavage (S2) and high-angle phyllosilicate-rich fault zones may be used in the future to distinguish these structures from low-angle ductile shear zones during drill core logging procedures.2.6  GeochronologyIn this section, new geochronological data is presented in an attempt to date the different deformation events documented in the Gibraltar Cu-Mo porphyry, and compare them to the timing of mineralization and intrusion. Previously published geochronology for the main ore-hosting Mine Phase tonalite are limited to a U-Pb zircon age of 211.9 ± 4.3 Ma (Oliver et al., 2009) and a recalculated K-Ar hornblende cooling age of 208 ± 12 Ma (Drummond et al., 1976; recalculated by Breitsprecher and Mortensen (2004) using IUGS decay constants). It is clear that the age of the Mine Phase tonalite is Late Triassic, and close to the age of mineralization (210–215 Ma; Harding, 2012); however, the 2σ error remains large. Other isotopic ages of Mine series and GMB intrusive phases are summarized by van Straaten et al. (2013), and modified in the summary section (refer to Figure 2.47).Only one previously ‘published’ age for the age of alteration in shear zones is alluded to on a revised open file map by Ash (open file map 1999-7; and revised July 2004). In the revised stratigraphic column, it is stated that “zone of quartz sheeted and stockwork Cu-Mo veins and veinlets are cut by younger (ca. 50 Ma) pervasive sericite quartz-chlorite altered, ore-grade shear zones. Here, six samples were collected from various structures to provide Ar-Ar (white mica) cooling ages and one sample for Ar-Ar (hornblende) cooling age (Figure 2.34). Samples collected from fault zones were carefully chosen such that the muscovite that was dated represents the cooling age of 120550000 UTM E  5817000 UTM NGibraltar EastGibraltar WestPollyannaGranite Lake EastGranite LakeGranite Lake West¯SFNF1NF2NF3PFNF4NF5NF6NF8aNF7NF10NF8bNF8NF9EF 2EF 1F10CFGLFGLFGLFGLFGFGFGFGFGFGFGLFNGFNGFNGFNGFNGFNGFNF8cEast Boundary FaultWarren FaultGLFGLFGLFNF9aGLFGLFGLFGLFDSZ 1Granite Mountain Phase TrondhjemiteMine Phase TonaliteLeucocratic Tonalite Dike Border Phase Quartz Diorite, DioriteQuaternaryFeldspathic Mine Phase Tonalite1 KilometreUnconsolidated glacial and alluvial depositsLate Triassic_^_^ Ar-Ar white micaU-Pb zirconAr-Ar hornblende_^10 ft contours, August 2013Lateral shear sense: dextral,sinistralFault, unknownN-S striking dextral normal faultsFault, reverse (Oliver, 2008) East Faults (EF)Low-angle normal faultsFault, reverse (this study), inferredLithological contact: dened,inferred (this study)contact (Oliver, 2008)Gibraltar Mine Geochronology Sample LocationsNM-13-001S1NM-13-002N-S trending dextralnormal faultNM-13-026BImbricate ductile thrustNM-13-035Sub-horizontal NE-vergent DSZ NM-13-040BNE-dipping conjugate faultNM-13-044Imbricate ductile thrust faultNM-13-009Mine Phase tonalite_^_^_^ _^^__^_^_^_^NM-13-001 DDHFeldspathic Mine Phase tonalite NM-13-039Sub-horizontal to SW-vergent DSZFigure 2.34 Ar-Ar white mica and hornblende (refer to location in drill core in Figure 2.37) and U-Pb zircon geochronology sample locations at Gibraltar mine.121muscovite that grew during the movement on the fault. A hornblende Ar-Ar cooling age is provided for the feldspathic Mine Phase tonalite. 2.6.1 U-Pb Zircon Geochronology2.6.1.1 Mine Phase tonalite; NM-13-009The sample collected for U-Pb geochronology is an equigranular Mine Phase tonalite with moderate propylitic alteration and 3-5 mm wide P veinlets that were overprinted by 1-2 cm wide QC veinlets and sericitization of plagioclase; collected from the 3400’ bench wall in GL East (Figure 2.35A). All veinlets and veins are parallel to a weak-moderate foliation. Slightly elongate quartz clasts (30-35%) are 1-3 mm in length and have weak undulose extinction. Subgrain formation and BLG recrystallization near quartz grain boundaries is common. Relatively undeformed, euhedral plagioclase (30-35%) are 2-3 mm in length, weakly to strongly sericitized and epidotized in proximity to, and within mineralization-stage veinlets. The majority of plagioclase grains are also aligned parallel to the main fabric (Figure 2.35B). Pyrite (3%) and chalcopyrite (1%) are associated with veinlets, and associated with mafics (<3%) as dissemination. Epidote (<1%) after plagioclase is often fine-grained (<10 µm) and are found within the P veinlets, or form a weak halo around the veinlet; few, very fine-grained disseminated grains are also observed. All veinlets contain quartz that show subgrain rotation (SGR) recrystallization. 2.6.1.2 MethodologySample preparation and CA-TIMS analysis was conducted at the Pacific Centre for Isotope and Geochronology Research Centre at the University of British Columbia. CA-TIMS methods followed procedures outlined by Mundil et al. (2004), Mattinson (2005), and Scoates and Friedman (2008). Zircons were handpicked in alcohol after standard mineral separation procedures have been followed. The clearest, crack- and inclusion-free grains of zircon are selected, photographed (Figure 2.35C) and then annealed in quartz glass crucibles at 900° C for 60 hours. Annealed grains are transferred into 3.5 mL PFA screwtop beakers, ultrapure HF (up to 50% strength, 500 mL) and HNO3 (up to four per liner) and about 2 mL HF and 0.2 mL HNO3 of the same strength as acid within the beakers containing samples are added to the liners. The liners are then slid into stainless steel Parr™ high pressure dissolution devices, which are sealed and brought up to a maximum of 200° C for 8-16 hours (typically 175° C for 12 hours). Beakers are removed from liners and zircon is separated from leachate. Zircons 122CBAFigure 2.35 Mine Phase tonalite collected for U-Pb zircon CA-TIMS geochronology. A. Sample collected from Mine Phase tonalite with a weak propylitic overprint, and cross cutting QC veinlets in the 3300’ bench wall in Granite Lake East (see map above). B. Hand sample (NM-13-009) of Mine Phase tonalite collected from Granite Lake East. C. Photomicrograph in transmitted light of zircon population selected for U-Pb geochronology.  123are rinsed with >18 MΩ.cm water and subboiled acetone. Then 2 mL of subboiled 6N HCl is added and beakers are set on a hotplate at 80°-130° C for 30 minutes and rinsed again with water and acetone. Masses are estimated from the dimensions (volumes) of grains. Single grains are transferred into clean 300 mL PFA microcapsules (crucibles), and 50 mL 50% HF and 5 mL 14 N HNO3 are added. Each is spiked with a 233-235U-205Pb tracer solution (EARTHTIME ET535), capped and again placed in a Parr liner 8-15 microcapsules per liner). HF and nitric acids in a 10:1 ratio, respectively, are added to the liner, which is then placed in Parr high pressure device and dissolution is achieved at 240° C for 40 hours. The resulting solutions are dried on a hotplate at 130° C, 50 mL 6N HCl is added to microcapsules and fluorides are dissolved in high pressure Parr devices for 12 hours at 210° C. HCl solutions are transferred into clean 7 mL PFA beakers and dried with 2 mL of 0.5 N H3PO4. Samples are loaded onto degassed, zone-refined Re filaments in 2 mL of silicic acid emitter (Gerstenberger and Haase, 1997). Zircons are robust minerals and most hydrothermal alteration at Gibraltar mine is not at high enough temperatures to affect the crystal walls of the zircon grains.A modified single collector VG-54R or 354S (with Sector 54 electronics) thermal ionization mass spectrometer equipped with analogue Daly photomultipliers measured isotopic ratios. Analytical blanks are 0.2 pg for U and up to 1 pg for Pb. U fractionation was determined directly on individual runs using the EARTHTIME ET36 mixed 233-235U-205Pb isotopic tracer and Pb isotopic ratios were corrected for fractionation of 0.25%/amu, based on replicate analyses of NBS-982 reference material and the values recommended by Thirlwall (2000). The Microsoft Excel-based program of Schmitz and Schoene (2007) was used for data reduction. Isoplot was used to construct standard concordia diagrams, and to calculate regression intercepts and weighted averages (Ludwig, 2003). Unless otherwise noted, all errors are quoted at the 2 sigma or 95% level of confidence. Isotopic dates are calculated with the decay constants I238= 1.55125E-10 and I235= 9.8485E-10 (Jaffe et al., 1971). EARTHTIME U-Pb synthetic solutions are analyzed on an on-going basis to monitor the accuracy of results. 2.6.1.3 Results The U-Pb zircon analysis yields an age of 216.17 ± 0.24 Ma (refer to U-Pb geochronology data in Table 2.7). This is congruent with previous analyses that were not conducted by CA-TIMS techniques (Drummond et al., 1976: recalculated by Breitsprecher and Mortensen (2004); Oliver et 124Table 2.7 U-Th-Pb analytical results for zircon from the Mine Phase tonalite of the Granite Mountain batholith from Gibraltar mineCompositional Parameters2,3,4,10 Radiogenic Isotope Ratios5,6 Isotopic Ages7,8Sample1 Weight9(mg)U(ppm)Pb(ppm)Th/U206Pb*(x10-13 mol)mol %206Pb*Pb*PbcPbc(pg)206Pb/204Pb208Pb/206Pb207Pb/206Pb% err 207Pb/235U% err 206Pb/238U% err corr.coef.207Pb/206Pb± 207Pb/235U± 206Pb/238U± NW-13-009 (Mine Phase tonalite): UTME 550344 UTMN 5817329A 0.0062 41 1.5 0.222 0.3643 97.30% 10 0.83 684 0.071 0.050958 1.705 0.242381 1.797 0.03449 0.244 0.436 238.93 39.31 220.37 3.56 218.63 0.52B 0.0052 167 5.6 0.22 1.2364 99.40% 46 0.62 3083 0.07 0.050754 0.738 0.238759 0.79 0.03411 0.167 0.409 229.69 17.04 217.4 1.55 216.27 0.35C 0.0041 222 7.4 0.219 1.2903 99.47% 53 0.56 3493 0.07 0.050537 0.713 0.237429 0.736 0.03407 0.175 0.249 219.76 16.49 216.31 1.43 216 0.37D 0.005 70 2.5 0.225 0.4949 98.00% 14 0.83 925 0.072 0.05073 2.392 0.238786 2.521 0.03413 0.315 0.462 228.58 55.24 217.43 4.93 216.4 0.67E 0.0024 59 2.2 0.222 0.2033 97.06% 9 0.51 629 0.071 0.050842 2.813 0.241246 2.972 0.03441 0.353 0.499 233.66 64.91 219.44 5.87 218.12 0.761A, B etc. are labels for fractions composed of single zircon grains or fragments; all fractions annealed and chemically abraded after Mattinson (2005) and Scoates and Friedman (2008).2Model Th/U ratio calculated from radiogenic 208Pb/206Pb ratio and 207Pb/235U age.3Pb* and Pbc represent radiogenic and common Pb, respectively; mol % 206Pb* with respect to radiogenic, blank and initial common Pb.4Measured ratio corrected for spike and fractionation only. Mass discrimination of 0.25%/amu based on analysis of NBS-982; all Daly analyses.5Corrected for fractionation, spike, and common Pb; up to 0.84 pg of common Pb was assumed to be procedural blank: 206Pb/204Pb = 18.50 ± 1.0%; 207Pb/204Pb = 15.50 ± 1.0%; 208Pb/204Pb = 38.40 ± 1.0% (all uncertainties 1-sigma).  Excess over blank was assigned to initial common Pb, using the Stacey and Kramers (1975) two-stage Pb isotope evolution model at 216 Ma.6Errors are 2-sigma, propagated using the algorithms of Schmitz and Schoene (2007) and Crowley et al. (2007).(g) Calculations are based on the decay constants of Jaffey et al. (1971). 206Pb/238U and 207Pb/206Pb ages corrected for initial disequilibrium in 230Th/238U using Th/U [magma] = 3.(h) Corrected for fractionation, spike, and blank Pb only.9Nominal fraction weights estimated from photomicrographic grain dimensions, adjusted for partial dissolution during chemical abrasion.10Nominal U and total Pb concentrations subject to uncertainty in photomicrographic estimation of weight and partial dissolution during chemical abrasion.1250.03390.03410.03430.03450.03470.228 0.232 0.236 0.240 0.244 0.248 0.252207 Pb/235 U206Pb/238U215217219NM-13-009216.17 ± 0.24 (0.32) [0.39] Ma weighted       Pb/      U  ageMSWD=0.82, n=3206 238Figure 2.36 Concordia plot showing U-Pb zircon CA-TIMS geochronological results for Mine Phase tonalite (NM-13-009) collected from Granite Lake East. Each ellipse represents error of 2σ per single grain of zircon. Red coloured ellipses represent the data used for the calculated 206Pb/238U weighted mean. Grey ellipses represent ellipses not used for the calculated 206Pb/238U weighted mean. 126al., 2009). This age slightly pre-dates the Re-Os molybdenite age of 210-215 Ma (Harding, 2012), and these ages are listed in Figure 2.47. There are two concentrations of zircon grains on the concordia plot (Figure 2.36) at 216 and 218 Ma. This phenomenon is caused by core inheritance and/or antecrysts as referred to by Miller et al. (2007). A portion of, or the whole batholith crystallized before another pulse of magma assimilated the older rock and created zircon overgrowths; thus giving two separate and distinguishable ages (Miller et al., 2007).2.6.2 40Ar/39Ar White Mica and Hornblende GeochronologySeven samples were collected from various structures to provide Ar-Ar (white mica) cooling ages and one sample for a minimum Ar-Ar (hornblende) cooling age of feldspathic Mine Phase tonalite. The feldspathic Mine Phase tonalite was selected instead of the Mine Phase tonalite because no fresh hornblende grains were observed in the Mine Phase tonalite samples collected. No whole rock geochemical studies have been conducted on the feldspathic Mine Phase tonalite, so the Mine Phase tonalite and feldspathic Mine Phase tonalite are assumed to be syngenetic based on their close spatial relationship and overlapping ages (208 ± 12 Ma; Breitshprecher and Mortensen (2004) after Drummond et al. 1976). Therefore, the minimum cooling age of the feldspathic Mine Phase tonalite should be similar to the minimum cooling age of the Mine Phase tonalite. X-ray diffraction (XRD) analysis was conducted on each Ar-Ar white mica sample to confirm the presence of white mica collected from each structural element. Samples collected from each respective structure or fabric were carefully chosen such that the muscovite that was dated represent the cooling age of muscovite that grew during the movement on the fault. The samples used for Ar-Ar geochronology are placed in geological and structural context in this section of the study (Figure 2.37 to Figure 2.45). Results are summarized in Figure 2.46 and Table 2.10.2.6.2.1 X-ray diffraction (XRD) analytical techniquesStandard muscovite-illite-sericite grain size analysis normally involves bulk sample analysis (van der Pluijm and Fritz-Diaz, 2013); however, because individual grains are necessary for the analysis of specific structures and folia, mineral separates were individually picked with tweezers under a binocular microscope and used for XRD analyses. Mineral separates in sample NM-13-001 were 127too small to individually pick, so the location of sericite fines were scraped with a razor blade, and then collected. Approximately 30-40 mg of white mica was picked from each sample. The accepted maximum particle size for clay minerals based on a spherical volume diameter is <2 μm fractions (Johns et al., 1954). To obtain this particle size clay separates were uniformly ground in a porcelain mortar and then mixed with ethanol, and the resulting paste was placed onto a Rietveld smear mount quartz plate, according to the methods outlined by Moore and Reynolds (1997). However, accuracy in obtaining a <2 μm may be compromised and it is important to note potential sample preparation factors that can contribute to error (e.g., Kisch and Frey, 1987; Kisch, 1991; and Warr and Rice, 1994). Smear mounts were analyzed by a Bruker D8 Focus (0-20, LynxEye detector) at the University of British Columbia at angles between 3° and 80° 2ϴ, using a step size of 0.03°. The scan rate was 0.9 s per step for a total time of 42 minutes at 60 rpm, 35 kV and 40 mA CoαK, and a 0.6 mm wide slit. A cobalt source was used rather than a copper source to detect low angle peaks that are not readily detectable with shorter wavelength x-rays which provides better peak separation (Stahly, 2012).X-ray diffraction peak intensity has been directly correlated to the abundance of minerals, and is a method by which to estimate relative quantities of minerals (Alexander and Klug, 1948; Pierce and Siegel, 1969; Ouhadi and Yong, 2001). Whole diffraction patterns were analyzed, and each reflection peak was inspected and accounted for (refer to Appendix I1 for diffraction peak intensities). Specifically, the 001 reflection peak for illite compositions at 10 � was assessed as it is commonly used to analyze illite crystallinity (Kubler, 1967; 1968; Velde, 1965), among other reflection peaks (e.g., 007; Warr and Rice, 1994). The intent of this analysis is to confirm the presence of white mica in the selected samples, and is not meant to be a complete study of clay mineralogy at Gibraltar as that is outside the scope of this study. Qualitative analysis was conducted with automated ‘search-match’ software that makes use of the International Centre for Diffraction Data PDF-4+ database identified other expected minerals in the crystallite samples. Short wave infrared reflectance spectroscopy analysis with Terraspec® Mineral Analyzer provided mineral identification of billets that are not included in this study, but provide background information. This analysis provides the oversight for proper selection and identification of minerals in the X-ray diffraction data with the use of the database. 1282.6.2.2 Results of XRD Analyses Two different 001 peaks define K-rich (muscovite-2M1) and Na-rich (paragonite-2M1) white mica (shown in Figure 2.38), along with a series of other diagnostic properties (refer to Appendix I1 diffraction intensity peaks). All samples show diffraction spectra that indicate the presence of muscovite-2M1; however, only samples NM-13-002, NM-13-026B, NM-13-035 and NM-13-039 yield a second peak at the 9.6 � that best fit with a paragonite-2M1 trend. There is no apparent correlation between these structures. Samples NM-13-001, NM-13-026B, NM-13-040B, and NM-13-044 contain muscovite-2M1 and all have a distinct and apparent association to mineralization (e.g., proximity to mineralization-stage veinlets and veins, and BQ veins). Although the other separates contain muscovite-2M1, their concentrations are relatively much lower than, or equal to the amount of paragonite-2M1. The °2θ illite crystallinity data at full width at half maximum (FWHM) are <0.25 °2θ (refer to Table 2.8) for all white mica XRD 001 reflection data, which represents formation within the epizone environment and part of a greenschist metamorphic facies (Verdel et al., 2011, 2012). It is suspected that the presence of Na-rich paragonite-2M1 is associated with later N-S dextral strike-slip faulting and reactivation of thrust faults; however, further interpretation and characterization of the white mica data may require microprobe analysis and a larger dataset.2.6.2.3 Sample Descriptions1. Feldspathic Mine phase tonalite; NM-13-001 DDH.Fresh hornblende was only observed in the feldspathic Mine Phase tonalite. This sample was collected from drill core, at a depth of 44.84 m, in south GL West pit (refer to map in Figure 2.34 and refer to drill core data in the inset of Figure 2.37). The sample is medium- to coarse-grained, unfoliated, and barren (Figure 2.37B). Weak to moderate sericitization of feldspars (45-55%) that are 10-15 mm large; minor, very fine-grained epidote also alters from feldspars. Subhedral to anhedral quartz (35-45%) are mostly 10-15 mm in size, with few grains larger than 50 mm. Relatively fresh, euhedral to subhedral hornblende (2-3%) are 10-20 mm, with few 30-35 mm-size grains. Hornblende is weakly altered to chlorite. Minor, bright green-coloured titanite (<1%) is very fine-grained (inset of Figure 2.37C).1292. Tectonic foliation (S1); NM-13-001.This sample contains a weak, but observable S1 fabric (110/49 SW), however, typically, the white mica is fine-grained. The sample is from the hanging wall of a dextral normal fault (North Fault 8b, GL West ramp; 3770-3950’ bench; Figure 2.39A) in the GL pit. At the outcrop scale, the S1 fabric is dragged into the dextral fault. The hand sample is a propylitically altered Mine Phase tonalite with QC veinlets; and clay alteration is common throughout the hand sample. QC veinlets in this hand sample are composed of quartz with chlorite aligned in the centre of the vein. Remobilization and recrystallization of quartz is commonly observed in veinlets oblique to the tectonic fabric (Figure 2.39C, D). Chlorite ± sericite (muscovite)-seams strike 275, and dip 50 towards the south, parallel to S1 fabric and oblique to QC veinlets (Figure 2.39B, D). Very fine-grained (<0.1 mm) muscovite-2M1was collected for Ar-Ar geochronology from the fresh surface of a discrete chlorite-sericite-seam (refer to Figure 2.38 for XRD diffraction peaks). 3. Dextral, normal fault; NM-13-002.This sample was collected from NF 8b on the West Connector Ramp (3770-3950’ bench) in GL West pit (Figure 2.34). A foliated zone comprises the 3 m-wide fault zone. The fault clearly drag-folds the S1 foliation in the footwall and hanging wall (Figure 2.40A), thus defining east-side down kinematics. The fault wall rocks are Mine Phase tonalite and are the location from which rocks were collected to date the S1 foliation (see above). The fault rock is composed of muscovite (40-50%), primary (30-40%) and secondary quartz (15-20%), limonite (12%), chlorite (3-5%), Fe- and Cu-oxides (~1%), and trace molybdenite. Stepped-slickenlines that plunge shallowly towards the SE, define a dextral shear sense (Figure 2.40B). The foliation is defined by 0.1-0.25 cm thick bands of muscovite, quartz, and minor chlorite, quartz σ-porphyroclasts, and minor mica fish comprise an apparent ductile fabric (Figure 2.40C). Microstructural observations of kinematic indicators confirm that the paragonite-2M1 collected for analysis was formed during dextral strike-slip movement (refer to Figure 2.38 for XRD diffraction data). 4. Imbricate ductile thrust fault; NM-13-026B.The sample was collected from an imbricate ductile thrust fault on the West Connector Ramp (3770’-3950’ bench) in GL West (Figure 2.34). The ductile thrust strikes 125, and dips 25 SW (Figure 1302.41A). The shear zone contains a thin layer of S-C mylonitic material that strikes 125 and dips SW, with thrusting towards the NE (Figure 2.41B). The composite fabric has the C-surface defined by discontinuous layers of chlorite and white mica; and the S-surface is defined by quartz and larger chlorite grains (Figure 2.41C). XRD analysis indicates the presence of both muscovite-2M1 and paragonite-2M1 that are <0.1 mm in size, and were collected from the C-surfaces (refer to Figure 2.38 for XRD diffraction peak data).5. Sub-horizontal ductile shear fabric enveloping boudinaged vein; NM-13-035.The sample was collected from a west-northwest trending fault that contains a large quartz vein boudin in south GL pit (refer to map in Figure 2.34; and refer to field photo of the 3800’ bench wall in Figure 2.42A). The shear fabric from which the sample was collected strikes 125, and contains a fabric that undulates with an enveloping surface that shallowly dips towards the south-southwest (Figure 2.42B). This shear fabric is only developed around the large quartz vein boudin. Stepped-slickenlines define a top-to-the-SW shear sense in hand sample (Figure 2.42C). The fabric is defined by chlorite and sericite layers with discrete molybdenite sheets, that alternate with deformed quartz layers with ankerite ± dolomite that occupy interstitial spaces and irregular pyrite. Very thin and discrete molybdenite sheets are interlayered with the white mica folia and define a weak S-C fabric (Figure 2.42D). The paragonite-2M1 (Figure 2.38) mineral separates used for Ar-Ar dating are 1-5 mm in size and were picked from the fabric with SW vergence.6. Sub-horizontal to low-angle, NE-dipping ductile shear zone; NM-13-039.This sample was collected from a sub-horizontal high strain zone in the Gibraltar West pit that steepens into a shallowly dipping fault that dips towards the NE and strikes NW (2950’ bench; Figure 2.43A, C): the NE dip is a result of folding. The dip shallows out towards the north and grades into the S1 fabric that is dragged into a ductile thrust. The sub-horizontal shear zone is discontinuous along strike. The Mine Phase tonalite sample contains weak QSC alteration with stronger Fe-oxidation of sulphides that comprise jarosite and minor goethite (Figure 2.43B). Muscovite (± chlorite)-folia envelope the elongated quartz-eyes that define quartz-folia. The quartz- and muscovite (± chlorite)-folia are interlayered and folded. Paragonite-2M1 (Figure 2.38) used for Ar-Ar geochronology are up to 2 mm in length, and picked from this sheared, and folded, muscovite-folia. The muscovite crystallites 131qtzhblplag olgser1 mmDDH: 2007-098Granite LakeCollar Azimuth: 0 Collar Declination: -90Mine Elevation: 4167.34’ (1270.21 m)Depth Down Hole EOH @ 737.7’S1: 55°S1: 80°,S2: 60°S1: 51° S1: 54° 351.8’S1: 67°S1: 48°1 cmhblepqtzplag0100 (ft)200300400500600700800NM-13-001 DDHNM-13-002 DDHNM-13-004 DDHNM-13-008 DDHNM-13-009 DDHNM-13-003 DDHNoneTraceWeakModerateStrongFoliationEp P QCAlpha AngleQSP/QSMRQVeinsCasingSample ID100 (m)200Figure 2.37 Sample location for Ar-Ar hornblende geochronology of NM-13-001 DDH within a deuterically altered Feldspathic Mine Phase tonalite in Granite Lake West (down-hole). Hornblende separates were picked from sample NM-13-001 DDH collected from 2007-098, shown in the bottom left inset, for 40Ar/39Ar analysis. Photomicrograph of NM-13-001 DDH is inset to the bottom right.132Figure 2.38 Figure of diagnostic 001 reflection data obtained from XRD analysis of white mica separates used for 40Ar/39Ar geochronology. Two notable peaks are identified; one at 10 � (2M1 muscovite) and another at 9.6 � (2M1 paragonite).Table 2.8 Table of 001 illite XRD reflection dataSample ID 2θ (Left Angle)2θ (Right Angle)Crystallinity (Å) (FWHM)FWHM (∆ °2θ)Crystallinity (Å) (I Breadth)I Breadth Net AreaNM-13-001 10.034 10.548 1024.7 0.1 902 0.114 27.88NM-13-002 10.262 10.465 1376.7 0.075 1408.6 0.073 1.459NM-13-026B 10.205 10.405 974.8 0.106 979.3 0.105 14.55NM-13-035 10.32 10.405 1624.1 0.063 1394.8 0.074 0.4921NM-13-039 10.291 10.405 1494.2 0.069 1532.1 0.067 2.086NM-13-040B 10.034 10.548 951.4 0.108 838.5 0.123 51.28NM-13-044 9.976 10.634 922.7 0.112 799.7 0.129 110.9Full width at half maximum (FWHM)133ser1 mmLooking westS1 chlqtzRx qtzveins1 cmQC veinletschlorite-seamsurfaceLooking towards 345˚ 1 mS1A BC_^_^_^_^_^_^_^_^1 mmDLooking westchl-ser seamchlFigure 2.39 Location of sample collected for 40Ar/39Ar (white mica) geochronology of the S1 fabric. Red dot in photographs depicts the location where NM-13-001 was collected from. A. S1 foliation is offset by North Fault 8b. B. QC alteration veins overprinting propylitically altered mine phase tonalite, and are oblique to the tectonic fabric. C. White mica aligned parallel to S1 foliation defined by elongate, partially recrystallized quartz porphyroclasts, and oblique to veins comprising of pervasively dynamically recrystallized quartz, XPL. D. Chlorite-sericite (muscovite after plagioclase)-seams oblique to recrystallized quartz veinlets, PPL.134ser341˚SFaultXPL1 mmCser341˚Looking towards 345˚1 mS1A BFigure 2.40 Location of sample collected for 40Ar/39Ar (white mica) geochronology of the strike-slip movement in the N-S direction. A. North-south trending dextral normal fault (NF 8b) drags the S1 foliation, Granite Lake West ramp. Red dot depicts the location where sample NM-13-002 was collected from. B. Hand sample photograph of white mica, and slickenside-steps that are sub-horizontally plunging towards the SE, define dextral shear sense. C. Map view photomicrograph of white mica parallel to partially recrystallized mantled porphyroclasts with rotational kinematics indicating dextral shear sense. 135ser1 mmLooking towards 340˚XPLserchlLooking towards 340˚qtzrx qtzser-chlA BCFigure 2.41 Location of sample collected for 40Ar/39Ar (white mica) geochronology of an imbricate ductile thrust fault with northeast vergence and top-to-the-northeast kinematics. Red dot in photographs depicts the location where NM-13-026B was collected from. A. The ductile thrust contains elevated copper grades in proximity to the shear zone (blue coloured copper oxides). B. Hand sample with mylonitic fabric defined by partially recrystallized quartz porphyroclasts with wings comprised of very fine-grained recrystallized quartz, collected from the centre of the shear zone. C. S-surfaces are defined by quartz porphyroclasts, sericite, and clays; and c-surfaces are defined by sericite and clay, all of which contribute to top-up kinematics.  136ser1 mmLooking towards 304˚pyrx qtzserankpyserchlankLooking towards 214˚A BC DLooking towards 214˚Figure 2.42 Location of sample collected for 40Ar/39Ar (white mica) geochronology of a sub-horizontal ductile shear zone that envelopes a quartz vein which strikes WNW. A. Photograph of the south Granite Lake 3800’ bench wall. Red dot in photographs depicts the location where NM-13-035 was collected from. B. Planar and crenulated fabric contains quartz, white mica, ankerite ± dolomite, and minor chlorite that wrap around quartz vein boudins of a WNW-trending oblique strike-slip fault. C. Step-fabric defined by white mica folia indicates southwest side-down kinematics. D. Photomicrograph of white mica and elongate quartz lamellae that define a strong fabric with uncertain kinematics. Irregular opaques are composed of pyrite and are likely remobilized. Ankerite comprises most of the interstices of the quartz matrix, mostly. Ankerite ± dolomite contains deformation twins, XPL. 137ALooking towards 336˚High strain zone enveloping surface1 mmXPLLooking towards 336˚serplagqtzDLooking towards 336˚S1B CstepsFigure 2.43 Location of sample collected for 40Ar/39Ar (white mica) geochronology of the shear fabric within the sub-horizontal to shallowly dipping northeast, ductile shear zone. Red dot in photographs depicts the location where NM-13-039 was collected from. A. Gibraltar West pit (Figure 2.14) and foliation dipping shallowly towards the northeast. B. Highly oxidized hand sample with a folded fabric, is enveloped by a surface parallel to the sub-horizontal ductile shear zone. C. White mica crystallites selected from fresh surfaces parallel to these slip-surfaces. D. White mica obtained from s-c fabric in photomicrograph showing top-to-the-southwest shear sense. 138A250 µmXPLLooking towards 338˚serrx qtzpyDS1Looking towards 345˚Looking towards 035˚BCFigure 2.44 Location of sample collected for 40Ar/39Ar (white mica) geochronology of a fabric that defines a northeast-dipping, conjugate ductile thrust fault. Red dot in photographs depicts the location where NM-13-040B was collected from. A. S1 fabric in the wall rock that is composed of propylitically altered Mine Phase tonalite with QSP overprint defined by veinlets with drag-fold relationships, cross cut by a low-angle ~1 m wide fault (338/44) with top-up shear sense. The fault contains ductile fabrics and is composed of a QSM vein, in Pollyanna 3870’ bench wall; hammer for scale. B. A different perspective of the fault shows the drag folding of S1 and QSP veinlets. C. Line drawing highlights the structural elements in (B). D. Static and dynamic recrystallization of quartz and sericite define a weak s-c fabric that indicates uncertain kinematics. 139ALooking towards 296˚1 mmXPLLooking towards 296˚serCBC’SLooking towards 296˚ 5 cmBFigure 2.45 Location of sample collected for 40Ar/39Ar (white mica) geochronology of fabric defining reverse and normal kinematics in a northeast vergent imbricate ductile thrust. Red dot in photographs depicts the location where NM-13-044 was collected from. A. ~1.5 m wide normal fault (110/22) contains a quartz vein and is interpreted as a reactivated thrust fault; Pollyanna 3870’ bench wall. B. Extensional shear bands in the footwall of the fault imply top-down kinematics, bottom left inset box in (A). C. Partially recrystallized mantled quartz σ-porphyroclasts contain strongly recrystallized tails that indicate top-up shear sense along with white mica along s- and c-surfaces. Chlorite is minimal.140and quartz porphyroclasts in the shear zone fabric define a top-to-the-SW shear sense (Figure 2.43D). 7. NE-dipping conjugate fault; NM-13-040B.This sample was collected from a SW-vergent (338/44 NNE) conjugate thrust fault from the Pollyanna pit (Figure 2.34). QSP veinlets dragged by the low-angle fault indicate NE side-up shear sense. This conjugate fault contains a 50 cm-wide QSM vein with tight, inclined to recumbent folds and a fabric (320/42 NE) that cross cuts an entire 10 m-wide folded package that contains QSP veinlets with open, upright folds (Figure 2.44A, B, C). At the microscopic scale, muscovite defines a strong vertical, dip-slip fabric, with many other white mica grains drag-folded into this fabric. Yet there are contradicting shear sense indicators that are ultimately uncertain (Figure 2.44D). Muscovite-2M1 grains for Ar-Ar geochronology are 1-2 mm, and were collected from this vertical fabric that defines the top-down shear sense in the meso-scale (refer to Figure 2.38 for XRD diffraction peak data; and refer to Figure 2.44D for photomicrograph).8. Imbricate ductile thrust fault; NM-13-044.This sample was collected from a shallowly dipping, ductile thrust fault (120/25 S) with NE vergence, in the 3870’ bench wall of Pollyanna pit (Figure 2.34). The fault contains a large 1.5 m thick, boudinaged quartz-vein (Figure 2.45A). The hanging wall and footwall have QSP veinlets that overprint a deuterically-propylitically altered Mine Phase tonalite. Well-developed shear bands in the footwall indicate top-down kinematics (Figure 2.45B). The muscovite-2M1 crystallites collected for Ar-Ar geochronology are 1-2 mm, and were collected from C-surfaces of S-C fabrics (refer to Figure 2.38 for XRD diffraction peak data; and refer to Figure 2.45C for photomicrograph). Oriented thin section analysis of mica-fish, S-C fabrics, and σ-porphyroclasts indicate top-up kinematics. The contrasting kinematic indicators are inferred to represent fault reactivation.2.6.2.4 MethodologyThe mineral separates were carefully selected from the fresh unweathered surface of each sample. Hornblende in Mine Phase tonalite was either non-existent, or extensively deformed and altered to chlorite and was not used for this study. Hornblende from feldspathic Mine Phase tonalite from south GL was selected instead to obtain a cooling age for a phase of the GMB. Mineral separates were individually picked with tweezers under a binocular microscope. Mineral separates in sample 141NM-13-001 were too small to individually pick, so the location of sericite fines were scraped with a razor blade, and then collected. A sample was not collected to analyze S2 crenulation cleavage after a number of attempts on several samples deemed the task unattainable.Samples were crushed in a ring mill, washed in distilled water and ethanol, and sieved when dry to -40+60 mesh. A groundmass concentrate was divided out of the bulk fraction using magnetic separation by discarding both the most magnetic and least magnetic material. Mineral separates were wrapped in aluminum foil and stacked in an irradiation capsule with similar-aged samples and neutron flux monitors (Fish Canyon Tuff sanidine (FCs), 28.201 ± 0.046 Ma (Kuiper et al., 2008). The samples were irradiated on March 24-28, 2014 at the McMaster Nuclear Reactor in Hamilton, Ontario, for 160 MWH in the medium flux site 8E. Analyses (n=36) of 12 neutron flux monitor positions produced errors of <0.5% in the J value. Isotopic ratios were measured between May and September 2014 at the Noble Gas Laboratory, Pacific Centre for Isotropic and Geochemical Research, University of British Columbia, Vancouver, BC, Canada. The mineral separates were step-heated at incrementally higher powers in the defocused beam of a 10W CO2 laser (New Wave Research MIR10) until fused. The gas evolved from each step was analyzed by a VG5400 mass spectrometer equipped with an ion-counting electron multiplier. All measurements were corrected for total system blank, mass spectrometer, as well as interfering Ar from atmospheric contamination and the irradiation of Ca, Cl and K (Isotopic production ratios: (40Ar/39Ar)K=0.0302 ± 0.00006, (37Ar/39Ar)Ca=1416.4 ± 0.5, (36Ar/39Ar) Ca=0.3952 ± 0.0004, Ca/K=1.83 ± 0.01(37ArCa/39ArK).).Initial data entry and calculations were carried out using the software ArArCALC (Koppers, 2002). The plateau and correlation ages were calculated using the program Isoplot ver.3.09 (Ludwig, 2003). Errors are quoted at the 2-sigma (95% confidence) level and are propagated from all sources except mass spectrometer sensitivity and age of the flux monitor. The best statistically-justified plateau and plateau age were picked based on the following criteria: 1. Three or more contiguous steps comprising more than 60% of the 39Ar;2. Probability of fit of the weighted mean age greater than 5%;1423. Slope of fit of the error-weighted line through the plateau ages equals zero at 5% confidence; 4. Ages of the two outermost steps on a plateau are not significantly different from the weighted-mean plateau age (at 1.8σ, six or more steps only); 5. Outermost two steps on either side of a plateau must not have non-zero slopes with the same sign (at 1.8σ, six or more steps only).2.6.2.5 ResultsThe plateau ages have the ability to portray any re-heating of the mineral history, so they are favoured in this study to represent the history of the selected white mica and hornblende (Figure 2.46). Step-heating spectra are good at detecting episodic Ar loss, contamination by non-atmospheric Ar, and the detailed assessment of the thermal history of a sample. Inverse isochron ages are also presented in Appendix J1. The inverse isochron and plateau age spectra are very similar for each sample (Table 2.9 and Table 2.10). Both sets of data are presented and reviewed below, however the plateau ages are used to represent the final analysis, unless otherwise specified. Closure temperatures vary for each mineral and depend on cooling rates, diffusion of the grain, temperature, and grain size (Dodson, 1973; Lee, 2009). Therefore, there is no exact closure temperature for any mineral system. The closure temperature for the Ar-Ar in hornblende is estimated to be 530°C ± 40°C (Harrison, 1981). It can be assumed that Ar-Ar ages represent cooling ages of muscovite at closure temperatures between 350°C (Ganguly and Tirone, 2009) and 375°(Knapp and Heizler, 1990)-~408°C (Hames and Bowring, 1994).1. Feldspathic Mine phase tonalite (hornblende): 142.3 ± 1.5 Ma.Sample NM-13-001 DDH yields an excellent plateau corresponding to result for the cooling age of hornblende in a feldspathic Mine Phase tonalite at 530°C ± 40°C (Harrison, 1981) with the plateau-age including 97% of the 39Ar. This age is 74 m.y. younger than the crystallization of zircon (>1000°C) at 216.17 ± 0.24 Ma (Figure 2.46A). Assuming the Mine Phase tonalite and feldspathic Mine Phase tonalite were syngenetic, the Ar-Ar age can either represent complete resetting of hornblende, or simply slow cooling over time. The substantially younger age may be a product of the batholith 143Table 2.9 40Ar/39Ar analytical results for hornblende from the feldspathic Mine Phase tonalite, and white mica from various structures and fabrics Step Laser Power (%)40Ar/39Ar 2σ 37Ar/39Ar 2σ r.i. Ca/K %40Ar atm f 39Ar 40Ar*/39ArK1 Age (Ma) ±2σFeldspathic Mine Phase tonalite: UTME 549236 UTMN 5817491NM-13-001 DDH (hornblende), J=  0.00145644 ± 0.000007281 2.3 865.49 25.49 2.9 0.1 0.041 0.08 98.87 0.41 9.745 27.03 ± 104.482 2.8 1111.41 22.59 2.95 0.08 0.017 0.06 78.51 0.76 238.854 568.1 ± 76.623 3.2 597.88 18.06 1.64 0.07 0.082 0.11 80.89 0.91 114.285 294.1 ± 77.014 3.6 372.34 5.77 1.16 0.03 0.073 0.28 92.2 0.94 29.035 79.37 ± 38.335 4.5 65.75 0.74 0.04 0 0.174 0.46 20.04 10.09 52.587 141.28 ± 3.816 5 60.71 0.6 0.03 0 0.035 0.61 13.33 19.31 52.628 141.39 ± 3.007 5.5 60.37 0.61 0.03 0 0.114 0.75 12.52 32.62 52.83 141.91 ± 2.998 6 58.57 0.57 0.02 0 0.067 0.48 10.58 22.83 52.383 140.76 ± 2.909 6.5 58.28 0.39 0.02 0 0.046 0.45 9.47 12.13 52.768 141.75 ± 2.17Integrated date: 141.55 ± 1.27S1 foliation(?): UTME 549446 UTMN 5818000NM-13-001 (white mica), J= 0.00147550 ± 0.000007381 2.3 128.08 15.3 0.32 0.04 0.005 0 74.6 0.89 32.531 84.78 ± 25.802 2.8 26.45 1.15 0.02 0 0.061 0 26.31 13.44 19.494 51.28 ± 4.593 3.2 22.86 1.02 0 0 0.001 0 4.29 21.34 21.88 57.46 ± 5.134 3.6 22.69 1.5 0 0 0.001 0 0.76 21.36 22.513 59.09 ± 7.715 4.1 21.07 1.04 0 0 0.008 0 1.75 24.73 20.702 54.41 ± 5.296 4.7 22.58 1.82 0 0 0.008 0 4.33 16.82 21.6 56.73 ± 9.037 6 117.71 71.7 0.03 0.02 0 -0.03 6.42 1.42 110.146 272.32 ± 308.08Integrated date: 55.22 ± 2.57Dextral, normal fault (NF 8b): UTME 549428 UTMN 5817984NM-13-002 (white mica), J= 0.00154532 ± 0.00000773 1 2.3 1301.95 80.6 4.32 0.29 0.062 0.01 98.14 0.19 24.243 62.75 ± 193.812 2.7 578.77 9.83 2.15 0.06 0.031 0 109.65 2.54 55.879 -153.5 ± 79.111 40Ar* = radiogenic 40Ar144Step Laser Power (%)40Ar/39Ar 2σ 37Ar/39Ar 2σ r.i. Ca/K %40Ar atm f 39Ar 40Ar*/39ArK1 Age (Ma) ±2σ3 2.9 53.85 0.79 0.13 0 0.016 0.01 69.51 3.06 16.421 42.74 ± 7.094 3.2 41.58 0.57 0.09 0 0.118 0 66.67 6.67 13.857 36.13 ± 4.815 3.5 22.73 0.28 0.02 0 0.056 0 30.08 7.9 15.895 41.39 ± 1.896 3.8 20.23 0.25 0.02 0 0.036 0 23.98 16.82 15.376 40.05 ± 2.057 3.8 20.83 0.43 0.02 0 0.024 0 24.81 8.36 15.666 40.8 ± 2.458 4.1 20.11 0.17 0.01 0 0.019 0 21.99 10.9 15.686 40.85 ± 1.049 4.6 20.86 0.58 0.02 0 0.023 0 22.29 11.05 16.207 42.19 ± 2.4710 5.5 17.07 0.15 0.01 0 0.017 0 12.95 8.53 14.861 38.72 ± 1.0211 6.5 16.83 0.3 0.01 0 0.161 0 10.17 13.24 15.122 39.39 ± 1.5512 7.5 16.35 0.15 0.01 0 0.016 0 10.55 10.75 14.623 38.11 ± 0.89Integrated date: 39.48 ± 0.47Imbricate ductile thrust fault: UTME 549113 UTMN 5817929NM-13-026B (white mica), J= 0.00144872 ± 0.000007241 2.3 537.07 12.5 1.82 0.06 0.059 0.01 99.89 1.96 0.596 1.56 ± 58.912 2.7 19.91 0.4 0.02 0 0.329 0 28.43 10.47 14.251 36.95 ± 2.383 3 15.73 0.2 0 0 0.055 0 7.29 23.95 14.58 37.8 ± 1.334 3.2 15.88 0.29 0 0 0.058 0 6.62 17.26 14.833 38.45 ± 1.815 3.4 15.39 0.34 0 0 0.047 0 3.23 12.43 14.892 38.6 ± 1.966 3.7 15.82 0.44 0 0 0.087 0 5.71 8.96 14.918 38.66 ± 2.577 4.2 15.94 0.38 0 0 0.09 0 6.03 10.37 14.975 38.81 ± 2.238 4.8 16.38 0.45 0 0 0.105 0 6.83 8.65 15.258 39.54 ± 2.649 5.6 15.5 0.74 0 0 0.07 0 4.6 5.94 14.785 38.32 ± 4.35Integrated date: 38.26 ± 0.73Sub-horizontal ductile shear fabric enveloping boudinaged vein: UTME 549742 UTMN 5817053NM-13-035 (white mica), J= 0.00145034 ± 0.000007251 2.3 64.35 6.89 0.16 0.02 0.312 0 74.03 1.51 16.713 43.31 ± 39.672 2.8 19.03 0.96 0.01 0 0.034 0 10.34 18.83 17.065 44.21 ± 5.151 40Ar* = radiogenic 40Ar145Step Laser Power (%)40Ar/39Ar 2σ 37Ar/39Ar 2σ r.i. Ca/K %40Ar atm f 39Ar 40Ar*/39ArK1 Age (Ma) ±2σ3 3.2 40.55 2.01 0.01 0 0.017 0.01 7.81 13.76 37.384 95.48 ± 9.884 3.5 15.44 1.65 0 0 0.27 0 3.8 17.53 14.855 38.55 ± 8.365 4 17.04 0.42 0 0 0.005 0 1.51 21.13 16.779 43.48 ± 2.236 5 18.76 0.95 0 0 0.015 0 7.62 14.41 17.328 44.88 ± 4.617 7 19.59 0.41 0.01 0 0.017 0 12.94 12.82 17.054 44.18 ± 2.15Integrated date: 44.82 ± 1.38Sub-horizontal to low-angle, SW-dipping ductile shear zone: UTME 546887 UTMN 5818401NM-13-039 (white mica), J= 0.00147368 ± 0.000007371 2.3 1303.46 200.02 4.33 0.71 0.001 0.54 98.22 0.59 23.238 60.89 ± 370.812 2.7 59.39 0.48 0.15 0.01 0.006 0.23 76.87 14.14 13.741 36.25 ± 14.263 3 27.96 0.43 0.04 0 0.001 0.38 43.49 29.72 15.802 41.63 ± 6.914 3.3 27.54 0.32 0.04 0 0.009 0.59 41.31 27.17 16.166 42.58 ± 7.465 3.6 52.19 2.47 0.09 0.01 0.003 2.62 50.88 10.2 25.66 67.12 ± 19.726 4 38.29 0.66 0.03 0.01 0.001 1.25 20.53 13.39 30.442 79.36 ± 14.787 4.5 74.04 1.71 0.01 0.03 0 0.02 5.78 4.78 69.767 176.97 ± 39.45Integrated date: 47.75 ± 4.40NE-dipping conjugate fault: UTME 549558 UTMN 5819039NM-13-040B (white mica), J= 0.00149144 ± 0.000007461 2.3 1593.7 76.92 5.36 0.28 0.075 -0.12 99.39 0.03 9.668 25.89 ± 220.662 3 116.97 2.87 0.36 0.01 0.18 0 91.79 0.49 9.609 25.73 ± 15.523 3.3 51.93 0.52 0.12 0 0.059 0 66.53 1.24 17.378 46.27 ± 4.364 3.6 26.03 1.15 0.03 0.01 0.094 0 29.22 2.84 18.423 49.02 ± 9.705 3.9 15.56 0.09 0.01 0 0.033 0 17.57 7.2 12.822 34.26 ± 0.546 4.1 14.26 0.13 0 0 0.069 0 7.98 8.43 13.12 35.04 ± 0.687 4.3 13.44 0.08 0 0 0.018 0 4.05 8.57 12.9 34.46 ± 0.438 4.5 13.33 0.1 0 0 0.008 0 2.17 9.33 13.037 34.82 ± 0.519 4.7 13.35 0.09 0 0 0.021 0 1.97 9.15 13.09 34.96 ± 0.471 40Ar* = radiogenic 40Ar146Step Laser Power (%)40Ar/39Ar 2σ 37Ar/39Ar 2σ r.i. Ca/K %40Ar atm f 39Ar 40Ar*/39ArK1 Age (Ma) ±2σ10 4.9 13.11 0.09 0 0 0.009 0 1.96 10.34 12.851 34.33 ± 0.4711 5.2 13.11 0.1 0 0 0.017 0 1.35 13.12 12.934 34.55 ± 0.5412 5.5 13.13 0.09 0 0 0.005 0 0.89 10.29 13.015 34.76 ± 0.4713 6 13.03 0.1 0 0 0.006 0 0.95 9.78 12.904 34.47 ± 0.5214 7 13.37 0.43 0 0 0.175 0 1.16 9.2 13.212 35.29 ± 2.26Integrated date: 34.63 ± 0.17Imbricate ductile thrust fault: UTME 549322 UTMN 5818880NM-13-044 (white mica), J= 0.00151062 ± 0.000007551 2.3 251.78 11.81 0.88 0.05 0.004 0.01 130.35 0.03 76.407 -221.78 ± 76.592 2.8 133.29 0.94 0.47 0.01 0.011 0 130.3 0.51 40.381 -113.81 ± 22.423 3.2 19.01 0.16 0.02 0 0.076 0 31.64 0.74 12.994 35.15 ± 1.564 3.6 17.65 0.12 0.01 0 0.007 0 13.98 1.47 15.185 41.01 ± 1.175 4 17.15 0.12 0.01 0 0.062 0 23.19 4.13 13.174 35.63 ± 1.026 4.2 16.48 0.15 0.01 0 0.051 0 21.78 5.95 12.893 34.88 ± 1.087 4.4 15.64 0.13 0.01 0 0.008 0 19.6 8.52 12.572 34.02 ± 1.018 4.6 14.94 0.13 0.01 0 0.06 0 13.57 10.87 12.914 34.94 ± 0.729 4.8 14.26 0.12 0 0 0.011 0 10.37 12.61 12.783 34.59 ± 0.6510 5.1 13.45 0.1 0 0 0.037 0 4.14 18.57 12.895 34.89 ± 0.5311 5.4 13.27 0.09 0 0 0.022 0 2.4 12.87 12.952 35.04 ± 0.4812 5.7 13.48 0.09 0 0 0.009 0 3.57 5.14 12.995 35.15 ± 0.5213 6 13.23 0.13 0 0 0.002 0 2.83 2.76 12.855 34.78 ± 0.7814 6.5 13.63 0.1 0 0 0.001 0 1.71 3.47 13.395 36.22 ± 0.5815 7 13.81 0.08 0 0 0.003 0 1.89 3 13.551 36.64 ± 0.5316 7.5 13.86 0.08 0 0 0.001 0 1.97 3.71 13.588 36.74 ± 0.5117 8 13.83 0.08 0 0 0.003 0.02 1.92 3.36 13.563 36.67 ± 0.5218 8.5 14.05 0.08 0 0 0.002 0.01 2.05 2.28 13.764 37.21 ± 0.65Integrated date: 35.8 ± 0.161 40Ar* = radiogenic 40Ar147Table 2.10 Summary chart of 40Ar/39Ar plateau and inverse isochron ages for the feldspathic Mine Phase tonalite and structures and fabrics at Gibraltar porphyrySample Steps Plateau age (Ma, ±2σ) (40Ar/36Ar)i* Inverse Isochron (Ma, ±2σ)MWSD (inverse isochron ages)MWSD (plateau ages)Feldspathic Mine Phase tonalite: UTME 549236 UTMN 5817491NM-13-001 DDH hbl 5-9 141.55 ± 1.9 277.8 ± 8.4 142.3 ± 1.5 0.22 0.102S1 foliation(?): UTME 549446 UTMN 5818000NM-13-001 white mica 2-7 54.9 ± 2.6 325 ± 59 54.1 ± 6.4 2 1.4Dextral, oblique strike-slip fault: UTME 549428 UTMN 5817984NM-13-002 white mica 3-9 40.85 ± 0.84 293 ± 12 40.91 ± 0.96 1.02 1.04Imbricate ductile thrust fault: UTME 549113 UTMN 5817929NM-13-026B white mica 1-9 38.26 ± 0.83 287 ± 12 38.30 ± 0.75 0.37 0.58Sub-horizontal ductile shear fabric enveloping boudinaged vein:: UTME 549742 UTMN 5817053NM-13-035 white mica 4-7 43.8 ± 1.5 309 ± 87 43.6 ± 1.8 0.67 0.4Sub-horizontal to low-angle, SW-dipping ductile shear zone: UTME 546887 UTMN 5818401NM-13-039 white mica 1-4 41.4 ± 4.8 300 ± 70 42 ± 15 2.4 0.21NE-dipping conjugate fault: UTME 549558 UTMN 5819039NM-13-040B white mica 5-14 34.61 ± 0.38 289.4 ± 9.8 34.57 ± 0.38 0.92 1.03Imbricate ductile thrust fault: UTME 549322 UTMN 5818880NM-13-044 white mica 5-13 34.92 ± 0.41 373 ± 23 34.85 ± 0.34 0.93 0.92* (40Ar/36Ar)i = initial ratio based on inverse isochron correlation diagram (errors reported at the 2σ level)1480204060801001201400 20 40 60 80 1000204060801001200 20 40 60 80 10010080604020008060402002040600 20 40 60 80 10039 Cumulative    Ar PercentApparent Age (Ma)0204060800 20 40 60 80 100100NM-13-039Sub-horizontal to SW-vergent DSZ0204060801000 20 40 60 80 100E FG H0204060800 20 40 60 80 100BC DA040801201602002402800 20 40 60 80 100 NM-13-002N-S trending dextralnormal faultNM-13-001S1NM-13-026BImbricate ductile thrustNM-13-035Sub-horizontal NE-vergent DSZ NM-13-040BNE-dipping conjugate faultNM-13-044Imbricate ductile thrust faultNM-13-001 DDHFeldspathic Mine Phase tonalite Figure 2.46 Interpreted plateau ages for Ar-Ar hornblende (A) and white mica (B-H) geochronology. Plateau steps are magenta, and rejected steps are cyan. Box heights are 2σ. 149system passing through the cooling temperature of the Ar-Ar (hornblende) system. Although both the plateau-age and inverse isochron age are similar, the amount of Ca in hornblende can affect the amount of Ar during the irradiation process (Ca/K= 1.83 ± 0.01) as 40Ca can be converted to 36Ar or 37Ar, and 42Ca can be converted to 39Ar. Phase changes in amphiboles is a common issue in step-heating analysis (Gaber et al., 1988; Lee et al., 1991); however, this does not seem to be a problem with the set of values that were yielded in this study. A similar age of 137 ± 10 Ma was produced by an unfoliated hornblende quartz diorite of the "Sheridan Phase" suggesting the two rocks formed synchronously (Breitsprecher and Mortensen, 2004); however, this limited data contradicts other ages of the Sheridan Creek stock (e.g., Ash and Riveros, 2001).2. S1 Foliation(?): 54.1 ± 6.4 Ma. This sample contained very fine grained sericite (muscovite) that may have caused recoil in the process. As a result, some 39Ar was likely lost during irradiation which causes an under-estimated amount of 39Ar in the grain and therefore under-estimates the amount of 40K. This produces an anonymously old calculated 40Ar/39Ar age. The yielded age is ~15 Ma older than all other white mica measurements, but still much younger than the age of the intrusion and mineralization (Figure 2.46B). The age-spectra contain large 2σ error bars that may represent contamination from chlorite and/or other clays. Some of the plateau steps suggest earlier formation from the crystallites, between 60 and 80 Ma. These ages should not be disregarded since they can represent the early tectonic deformation contemporaneous with the onset of Pinchi fault activation. Sericite after chlorite may have formed during, or after the earliest deformation event, and this is represented by the plateau-age that ultimately overprints and resets earlier deformation. The plateau-age includes 99.11% of the 39Ar that represents earlier cooling temperatures away from larger structures that may be misrepresented due to recoil, and the real age is younger. 3. Dextral, normal fault (NF 8b): 40.91 ± 0.96 Ma.The plateau-age for dextral strike-slip movement on NF 8b includes 64.8% of the 39Ar and indicates rapid cooling (Figure 2.46C). Three plateau steps at higher temperatures were not included as part of the plateau age. These three steps may have been caused from phase changes as the temperature increased past a certain threshold; however, this is not common for white mica as it is 150for amphiboles (Gaber et al., 1988; Lee et al., 1991). This age coincides with activation of the Fraser River Fault system in the Eocene. This age spectra contains multiple plateaus that represent Ar trapped in the core of the mineral. Numerous plateaus can indicate a different cooling history or potential recrystallization. However, this different set of plateau steps would have to represent an earlier age, and that is not the case. A series of plateaus yield ages of 38-39 Ma; however, these plateaus are interpreted to represent inclusions since the Ar was released at increased temperatures. The Ar released at higher temperatures reflects later ages than the representative age spectra chosen for the sample.4. Imbricate ductile thrust fault: 38.30 ± 0.75 Ma.The age spectra of sample NM-13-026B includes 100% of the 39Ar and is well defined. The muscovite formed during ductile thrust formation underwent rapid cooling (Figure 2.46D). There is high-confidence in this plateau-age, but this is unexpectedly younger than most of the other structures. Since S1 and ductile thrusts are interpreted to have formed through progressive deformation in D1, the age of this sample was expected to be older. This suggests that compressive stresses were a part of a later deformation event rather than a separate and preceding regional deformation; or the sericite was reset by later, nearby fault activation or reactivation, or by fluid flow.5. Sub-horizontal ductile shear fabric enveloping boudinaged vein: 43.6 ± 1.8 Ma.With the exception of one step in the age spectra, this analysis yields a concordant set of values that includes 65.9% of the 39Ar, and is similar to the inverse isochron data (Figure 2.46E). There is a slight spike in Ca/K content for the one misplaced step caused by impurities in the white mica, or contamination from ankerite and/or dolomite material in the sample. The plateau age, although containing relatively high uncertainty, coincides with the onset of dextral strike-slip faults related to the Fraser River fault system and reactivation of the Pinchi Fault system (Gabrielse et al., 2006). Regional exhumation recorded for various metamorphic core complexes are contemporaneous with this time, and this better represents the latest deformation along this sub-horizontal shear zone (Ewing, 1980). 1516. Sub-horizontal to low-angle, NE-dipping ductile shear zone: 41.40 ± 4.8 Ma.The plateau-age includes 71.6% of the 39Ar with two distinct series of steps, one from 0-71.6 per cent cumulative 39Ar providing a younger date that appears to be concordant and consistent with the S1 age and within the Late Paleocene-Early Eocene. A series of steps that define a plateau for a minimum age averaging close to 80 Ma is discordant and diagnostic of slow cooling mica (Figure 2.46F). The inverse isochron data yields an age of 42 ± 15 Ma that does not cover the minimum plateau age of the age spectra chart, but provides a more representative error range. It is very likely that the white mica have been re-heated and the Ar was reset (refer to Appendix J1). Although containing relatively high uncertainty, this age also coincides with early displacement of the Eocene Fraser River fault system. Therefore normal reactivation along an existing sub-horizontal to shallowly NE-dipping ductile shear zone is plausible. 7. NE-dipping conjugate fault: 34.57 ± 0.24 Ma:White mica that defines normal fault activation on a low-angle fault yields an age spectra that includes 95.4% of the 39Ar and is strongly concordant. A single exception lies with a plateau step that is inferred to represent Ar from fractures within the mineral or the outer rim, or excess Ar (Figure 2.46G). The plateau age represents the youngest cooling age sampled in this study. Although the step-heating age spectra does not indicate reactivation, field and microstructural analysis indicate two deformation events with the youngest deformation represented by the minimum plateau steps.8. Imbricate ductile thrust fault: 34.85 ± 0.34 Ma.The age spectra of sample NM-13-044 includes 81.4% of the 39Ar and yields a relatively strong concordant plateau age (Figure 2.46H). With the exception of a few steps that reflect Ar released from the mineral at higher temperatures (not included in the age spectra). These outliers likely represent a phase change, or may represent a core with Ar from a separate cooling environment at different time. These steps indicate an older age (~36-37 Ma) that is closer to the age of the other ductile thrust that was analyzed. So, two deformation events are identified; 1) initial ductile thrust fault formation, and 2) normal fault reactivation.1522.6.3 Summary of ResultsU-Pb (zircon) analysis yielded a Late Triassic crystallization age of 216.17 ± 0.24 Ma for the Mine Phase tonalite, that agrees with previously published geochronology for the main ore-hosting Mine Phase tonalite (Figure 2.47). The age of the Mine Phase tonalite precedes the age of mineralization (210-215 Ma; Harding, 2012). Leucocratic tonalite dikes form over the duration of ~5 m.y. of mineralization (e.g., 212 Ma; Ash and Riveros, 2001). The coinciding timing of mineralization and alteration and the leucocratic tonalite dikes suggest they are syngenetic, as proposed by Bysouth et al. (1995). However, the dikes are cross cut by QSP and P veinlets which indicates late telescoping alteration zonation that progresses back through deeper portions of the porphyry system and subsequently cuts dikes (Fournier, 1999). The ~2 m.y. difference in time between dike formation and mineralization is common for precursor plutons and their associated porphyry Cu stocks (e.g., Dilles and Wright, 1988; Casselman et al., 1995; Mortensen et al., 1995; Dilles et al., 1997). The range of Granite Mountain Phase trondhjemite crystallization ages (Figure 2.47; Ash and Riveros, 2001; Oliver et al., 2009; Schiarizza, 2015, 2016) "flank" the age of the Mine Phase tonalite obtained in this study, and so it is concluded that the two phases of the GMB formed at essentially the same time. The compositional gradient of the GMB proposed by Bysouth et al. (1995) is not supported by the geochronological data. Instead, the ages show a minor correlation between the youngest rock and the highest felsic content. This hypothesis is based on very little whole rock geochemistry data and geochronology with little variation, and requires further study. Two very distinct groupings of U-Pb zircon ages are identified in the U-Pb zircon geochronology, and they are addressed herein. Two of the five zircons used for the U-Pb geochronology show a distinct isochron plot that is slightly older in age (~218 Ma). This age is interpreted to represent antecrysts in the Mine Phase tonalite of the GMB. Antecrysts are zircon crystals formed early within the magma chamber that are slightly older than the final crystallization age (Miller et al., 2007). Studies of recent volcanic rocks suggest antecrystic zircons can be as much as 300,000 years older than the age of the eruption (Bacon and Lowenstern, 2004; Bachman et al., 2007). Antecrystic zircons can be separated from the walls of a magma chamber and incorporated into a crystallizing melt via convection, and ultimately included as part of an intruding porphyry stock (Miller et al, 2007). The presence of antecrysts with slightly older ages can cause uncertainties in calculated age (pers. comm. Friedman).153The Ar-Ar hornblende cooling age of 141.55 ± 1.9 Ma for the feldspathic Mine Phase tonalite going through the blocking temperature at 530°C ± 40°C (Harrison, 1981) is ~74 m.y. after the crystallization of zircon at ~1000°C of the Mine Phase tonalite (Figure 2.47; Breitsprecher and Mortensen, 2004; recalculated from Drummond et al., 1976). There is no known tectonic event in the region that coincides directly with ~140 Ma. However, the plateau steps for the Ar-Ar hornblende analysis are concordant and robust which infers a relatively quick cooling rate which agrees with Larsen (1948), given the size of the GMB as seen on surface. The Sheridan Creek stock, located 5 km to the south is in fault contact with the GMB and has been dated at 108 Ma (U-Pb zircon; Ash & Riveros, 2001), which is too young to have reset the hornblende. It is possible that the Ar was reset, possibly by an unexposed pluton. Since the robust minimum Ar-Ar hornblende step-heating plateaus are concordant, there is no record of slow-cooling processes within the released Ar to reflect any reset of Ar in hornblende. It is most likely that the feldspathic Mine Phase tonalite could potentially be simply younger than the Mine Phase tonalite: i.e., it intrudes the GMB in the Early Cretaceous at an unknown depth, crystallizes, during which time the hornblende crystallizes and cools below its closure temperature. The pluton emplacement is subsequently never heated above its closure temperature. Hence, the cooling age represents an approximation of the crystallization age of the pluton.All of the Ar-Ar (paragonite-2M1 and muscovite-2M1) minimum cooling ages yield results spanning 54-36 Ma (Eocene; Figure 2.48). These results post-date the timing of intrusion of the Mine Phase tonalite and all other phases of the GMB, and the timing of mineralization. Nevertheless, the Ar-Ar geochronological results are consistent with the timing expected for the activation time of the nearby Fraser River fault system (Ewing, 1980; Struik, 1993; Price and Monger, 2002) and the reactivation of the Pinchi fault system (Gabrielse, 2006). However, cross cutting relationships suggest that N- to NE-vergent structures should precede the N-S striking dextral normal fault, which is only sometimes consistent with the age spectra results. The step-heating and inverse isochron minimum ages define a slightly younger age for ductile thrust faults than the N-S trending dextral normal fault. All the samples cooled to temperatures of 350°-408°C in the Eocene; this includes ductile thrust faults and a N-S trending dextral strike-slip fault within the Eocene. However, the S1 fabric with the earliest age contains an age spectra with relatively large error bars that could place D1 in the Late Cretaceous. Similar plateau steps are observed in the sub-horizontal to SW-vergent ductile shear zone which is interpreted to have been reactivated in the Eocene. Previous work by Drummond et 154Feldspathic MinePhase tonaliteGranite MountainPhase trondhjemiteLeucocratictonalite dikesMineralization230 220 210 200215.0±0.8215.0±1.0212.7±0.9210.1±0.9216.17±0.24212.0±0.4150 130208±12141.55±1.9Age  (Ma)211.9±4.3209.6±6.3217.15±0.20Mine PhasetonaliteTriassic Jurassic Cretaceous(1)(2)(3)(1)(2)(4)(6)(4)(5)(5)(5)U-Pb (zircon)K-Ar (hornblende)Ar-Ar (hornblende)Re-Os (molybdenite)Figure 2.47 Summary of geochronological analyses for the intrusive phases of the Granite Mountain batholith and mineralization at the Cu-Mo Gibraltar porphyry. Arrows indicate samples collected and analyzed in this study. Rectangles include 2σ error. 1: this study; 2: Oliver et al. (2009); 3: Drummond et al. (1976), recalculated by Breitsprecher and Mortensen (2004) using IUGS decay constants; 4: Ash and Riveros (2001); 5: Harding (2012); 6: Schiarizza (2015). Double dashed-lines represent the period boundaries.Age  (Ma)30405060S1Imbricateductile thrustImbricateductile thrustN-S striking, dextral normal faultSub-horizontal toSW-vergent,shear zoneSub-horizontalNE-vergent, shear zone NE-dippingconjugate fault54.9±2.640.85±0.8438.26±0.8343.8±1.541.4±4.834.61±3.834.92±0.41 Ar-Ar (white mica)Paleocene Eocene OligoceneFigure 2.48 Summary of Ar-Ar (white mica) plateau-ages of various structural elements at Gibraltar mine and their temporal relationships. Rectangles include 2σ error. Double dashed-lines represent the epoch boundaries.155al. (1976) that yielded two K-Ar biotite ages that range from ~82-84 Ma. These Late Cretaceous ages were interpreted by Drummond et al. (1976) to have been caused by chloritization of biotite during peak regional metamorphism in the Intermontane Belt. Although thrust fault formation during the Eocene associated with the Fraser River fault is not uncommon (e.g., Hungry Valley Fault; Coates, 1974; Mathews and Rouse, 1984), the presence of contradicting shear fabrics on individual structures suggests that earlier fabrics, like S1, were overprinted, and white mica was reset in the Eocene during D2. The range in Ar-Ar ages implies white mica formation was caused by episodic fluid flow, rather than by intrusive activity. The geochronology is further discussed and placed into a regional context with temporal relationships in the discussion section. 2.7  Discussion2.7.1 Sequence, Style, and Physical Conditions of Deformation Events Affecting the DepositThe formation of the main foliation (S1), the moderately dipping ductile thrust faults and imbricate thrust faults, and associated folds are all part of a progressive deformation (D1). Mineralized sheeted veins that occur parallel to sub-parallel to S1 act as pre-existing ‘C’ surfaces and locally facilitate the formation of S-C mylonites. NW- to NNE (N-S) striking dextral faults ± normal displacement contain brittle fault rocks (foliated cataclasites) indicating their formation in upper levels of the crust. These faults demonstrably post-date the thrust faults, and likely formed at higher levels in the crust than the main foliation (S1) and associated thrusts and folds. Large northeast-striking normal faults (e.g., Fault 10; strikes 200 and dips 44 towards the NW; offsets the ore and GLFs by ~60 metres), with 10’s to hundreds of meters of displacement are the youngest faults on the property. Shallowly SE plunging intersection lineations, crenulation lineations, and fold axes are formed only in moderately to steeply dipping structures that contain abundant phyllosilicates: i.e., in weak rocks (they are very common in dextral strike-slip faults). The first deformation event (D1) is pervasive in all pits but varies in intensity. Within each pit, packages of well-foliated rock are commonly separated by packages of massive, undeformed tonalite. The intensity of the tectonic foliation (S1) increases to a mylonitic fabric in proximity to ductile shear zones in all pits. S1 orientation varies in orientation within and between pits likely as a result of folding; however, there is a general trend towards more southerly dipping in the Pollyanna and Granite Lake pits and more southwesterly dipping in the Gibraltar East and Gibraltar West pits. Ductile 156thrust faults either host (e.g., Gibraltar West and Gibraltar North) or bound the orebodies (e.g., Granite Lake, Pollyanna, and Gibraltar East pits). Ductile thrust faults strike easterly in the Pollyanna and Granite Lake pits, southeasterly in Gibraltar North, and Gibraltar East pit, and Granite Lake pit contains elements is contains elements of both (refer to geology map in Figure 2.4). This rotation is likely caused by later faulting (see below). The maximum temperature of deformation during the D1 event is constrained to less than 450°C, and is likely more on the order of 300°-350°C. Quartz is plastically deformed in the mylonites, and shows bulge recrystallization textures. Laboratory experiments extrapolated to geologic conditions demonstrate that quartz begins to deform by solid-state mechanisms near ~280°-300°C, and bulge recrystallization occurs at ~350°C (Stipp et al., 2002; Passchier and Trouw, 2005). These temperature estimates assume dry, quartz-rich rock; however, the presence of water decreases the strength of quartz (Luan and Paterson, 1992; Kronenberg, 1994; Gleason and Tullis, 1995; Kohlstedt et al., 1995; Post et al., 1996). For example, an increase in pore fluid pressure results in an increase in water fugacity in quartz grains, thereby promoting the mobility of dislocations, which decreases the dislocation creep strength of quartz (Luan and Peterson, 1992; Post et al., 1996). Plagioclase is loosely fractured, but rarely shows undulose extinction in the grain boundary migration (GBM). Plagioclase starts to deform by dislocation creep at ~450°C (Tullis et al., 1991; Tullis and Yund, 1992), but it can deform by dislocation glide at lower temperatures ~400°C (since glide does not contain climb of dislocations (Tullis and Yund, 1992)). Hence, the temperature of deformation must have been less than 400°C. The X-ray diffraction analysis of white mica obtained from foliation associated with D1 structures shows that the mica is composed of muscovite-2M1 and paragonite-2M1 001 which represent low-grade metamorphic conditions, typical of greenschist and epizone environments (e.g., temperatures of ~200°-350°C; Verdel et al., 2011, 2012), and consistent with deformation microstructures. Chlorite alteration is widespread within the Gibraltar mine, the surrounding GMB, and nearby plutons (e.g., Sheridan Creek stock). Chlorite and epidote are ubiquitous in the adjacent Cache Creek rocks (Schiarizza 2013; 2014) and are a result of lower greenschist regional metamorphism. Chloritic alteration is associated with propylitic alteration during porphyry emplacement and with regional metamorphism, but a differentiation of the two texturally and chemically, has yet to be made (e.g., 157Sutherland Brown, 1974; Drummond et al., 1976; Ash and Riveros, 2001; Oliver et al., 2009). Chlorite is present in the necks of large, boudinaged quartz (BQ) veins: the boudinage is interpreted to have formed during D1, and hence, chlorite is interpreted to have been precipitated during D1. At the Gibraltar pits, it is proposed that some (most?) of the chlorite has likely been recrystallized to reflect the prevailing T, P, Pρ conditions during deformation and it is used here to support a 300°-350°C temperature range during deformation. The sulphides provide fewer constraints on temperature. Chalcopyrite is locally elongate but pyrite, when deformed is fractured. Based on experimental work, chalcopyrite can deform plastically at temperatures >200°C; Clark and Kelly, 1973; Marshall and Gilligan, 1987), and pyrite requires >450°C (Cox et al., 1981) to deform plastically.2.7.2 Timing of Deformation Relative to Late Triassic Porphyry MineralizationThe Granite Mountain batholith (GMB) is commonly interpreted as a syntectonic intrusion such that batholith emplacement, deformation, hydrothermal alteration and mineralization occurred concurrently. In this model, the ductile thrust faults (e.g., Granite Lake Faults; GLF’s) and S1 cleavage formed coevally with, and exerted a first-order control on, the spatial distribution of alteration and mineralization (Sutherland Brown, 1974; Drummond et al., 1976; and Bysouth et al., 1995; Oliver et al., 2009). Here, it is interpreted that deformation post-dates the porphyry-style mineralization, although the observations collected for this research are not conclusive. This conclusion is based on the following observations:1. The temperature attending the earliest deformation (S1 and ductile thrust faults) is demonstrably less than 450°C and is likely more in the range of 300°-350°C. In the Granite Mountain batholith, there is not a clear transition from a magmatic foliation to solid-state deformation in the ductile faults and this is a common observation in syntectonically-emplaced plutons (e.g., Vernon et al., 1989; Paterson and Tobisch, 1992; Miller and Paterson, 1994). The complete lack of plasticity in plagioclase located in the shear zones strongly indicates that the shear zones did not form during cooling of a pluton under a directed stress (e.g., Paterson and Tobisch, 1992). 2. The Sheridan pluton is in sheared contact with the southern border of the GMB (e.g., Schiarizza, 2014). This is a steeply dipping, ductile fault with S-C mylonite fabrics indicating top-to-the-NE. The orientation and kinematics of the shear zone are the same as the GLFs in the Gibraltar pits (Figure 2.49). The intrusion of the adjacent Sheridan Creek stock has been dated as 108.1 ± 0.6 Ma 158UTM ProjectionZone 10NAD 83Granite MountainWarren FaultN122.09º52.70º122.37º52.435º0 5kmGeology of the Granite Mountain Batholith Map Area55834272468336384547364641503070 72324975 72203238152045272271552172583315308446316043854844498858287270526461853651614051434032536570351525 13265480588176354512181081022Saddle FaultPollyanna FaultConnector FaultGibraltar West FaultNorth Fault 8Fault 10Sheridan FaultEast Boundary Fault1234159     QuaternaryFault contact; inferredLithology contact; inferredBasaltUnconsolidated glacial,alluvial and colluvial depositsEarly CretaceousSheridan Creek stock: tonaliteEarly JurassicLower to middle JurassicDragon Mountain successionGabbroConglomerateSlate, siltstone, sandstoneLate TriassicGranite Mountain batholithGranite Mountain phase: trondhjemiteMine Phase: tonaliteBorder Phase: quartz dioriteBurgess Creek stockTonalite, quartz diorite, diorite, leucotonaliteTonalite, leucotonaliteUpper TriassicNicola GroupVolcanic sandstone, mac and felsic volcanic breccia; conglomerate, basalt, limestoneCuisson Lake unit (mac-rich phase)Chlorite schist, limestone, skarn, chlorite-sericite-quartz-feldspar schistCarboniferours to Lower JurassicCache Creek ComplexChert, phyllite, limestone, basaltExploration targetsBedding, tops known; right-way-up,overturned6542804076Bedding, tops unkown; inclinedCleavage or schistosity; inclined, verticalDuctile high-strain zone; inclined, vertical, dextral, sinistralFigure 2.49 Geology of the Granite Mountain batholith map area. Modified after Schiarizza (2015) and Bysouth et al. (1995). Prospective exploration sites are starred; numbers correspond to the order they are mentioned in text and their size infers relative potential for ore mineralization. 160U-Pb zircon; Ash and Riveros (2001), and 108.57 ±.09 Ma (U-Pb zircon; Schiarizza, unpub. data): hence the foliation post-dates 108 Ma. It is reasonable to interpret the fabrics within this ductile fault to be correlative to fabrics formed during D1 in the Gibraltar pits; hence, the ductile thrust faults post-date 108 Ma and cannot be formed in the Late Triassic.  3. Cross cutting relationships: the S1 foliation is deflected across a QC veinlet (refer to sample photograph and microphotograph in Figure 2.18A, B). The deflection is probably a result of rheological contrasts between the vein and the matrix. This cross cutting relationships shows that the hydrothermal veinlet was emplaced prior to the formation of the foliation. 4. The collective Ar-Ar geochronology cooling ages for white mica defining foliations, yield a minimum cooling age range from ~54 to 36 ± 5 Ma (refer to summary chart in Figure 2.48). These ages are much younger than the timing of mineralization (210-215 Ma, Re-Os; Harding, 2012) and intrusion (216.17 ± 0.24 Ma; U-Pb CA-TIMS zircon). The Ar-Ar geochronology is complicated, and there is potential for resetting of some of the ages. The step-heating and inverse isochron minimum ages define a younger age for ductile thrust faults than most of the N-S dextral strike-slip faults ± normal displacement: based on field observations the dextral strike-slip faults are demonstrably younger than the thrust faults. The S1 fabric does have the earliest date, and contains an age spectra with relatively large error bars, suggesting that it could have an earlier age of: 1) Late Cretaceous, or 2) LateTriassic where D1 post-dates the GMB intrusion and accompanies porphyry-related alteration/mineralization ~2 m.y. later, possibly during thrusting and docking of the Quesnel terrane. It is unclear if the error in the ages are a result of resetting of the Ar-Ar due to differential uplift or local reheating, or more likely(?) due to fluid flow along faults. 2.7.3 Strain Localization in Hydrothermally Altered RocksThe spectacular, high strain deformation observed in the porphyry does not extend much beyond the deposit itself. For example, the trondhjemite that forms the northern border to the Mine Phase tonalite, is pervasively brittly deformed, not ductiley deformed (no foliation is present). The trondhjemite is not foliated because it was relatively strong since it did not undergo significant hydrothermal alteration (e.g., Bysouth et al., 1995). Less altered panels of rock within the Mine Phase tonalite are similarly not deformed (e.g., feldspathic Mine Phase tonalite). The ductile high strain zones (thrusts and strike slip kinematics) are probably formed only as a result of strain localization 161into the pre-existing, weak, alteration mineralogy associated with the porphyry hydrothermal event. Outside the porphyry alteration system, the rocks are too strong to accommodate ductile deformation, and the high-angle and low angle shear zones observed in the pits, either terminate in the stronger, unaltered rocks, or localize into discrete brittle faults. The surrounding country rocks to the north locally have a northwest striking, steeply dipping axial planar cleavage that Schiarizza (2015) assigns to Middle Jurassic contraction. At Gibraltar, shear strain and flattening are partitioned into chlorite-sericite rich layers and veinlets. The S1 foliation is commonly (~68%) sub-parallel to chlorite-quartz-chalcopyrite veins and S-C mylonites commonly have chlorite veinlets or chlorite seams oriented parallel to the S or C orientation. PA veinlets may have formed by fracture filling along discrete planes during the earliest deformation. The S-C fabric is defined by mineralization-stage veinlets, aligned and elongate quartz grains, and stretched copper sulphides. It is proposed that during NE-directed thrusting, mineralization-stage chlorite-quartz-chalcopyrite veinlets, oriented with a pre-existing shallow dip, were reactivated as “C” surfaces, along which slip occurred (chlorite is always slickensided in the mylonites). These veinlets acted to partition strain preferentially into chlorite alteration zones. These pre-existing surfaces became kinematically linked with the S foliations, and formed S-C mylonites. If the veinlets were more steeply dipping during N-NE directed thrusting, they were rotated into either an S orientation or transposed into the C surfaces. In this kinematic model, the presence of sheeted chlorite-rich veins, promoted the formation of S-C mylonites and may have been instrumental in localizing the spatial distribution of the large ductile thrust faults. Strongly deformed leucocratic tonalite dikes are spatially associated with ankerite-quartz (AQ) alteration and ductile thrusts at the Gibraltar Cu-Mo porphyry (Oliver et al., 2009; Ash and Riveros, 2001) and it is interpreted that the contacts between leucocratic tonalite dikes (striking ~E-W) and Mine Phase tonalite were also used to localize ductile thrust fault formation.  2.7.4 Gibraltar Deformation in Regional Geologic ContextHere, a brief outline of the tectonic evolution of the Quesnel arc is provided in order to set the scene for a more detailed description of the structural evolution of the Gibraltar Cu-Mo porphyry deposit. 162A. JurassicB. mid-Cretaceous?C. Late Cretaceous - EoceneD. Late EoceneNAncestral North AmericaCu-Mo porphyry emplacement; Subsequent accretion of Quesnel ArcGMB intrusion; U-Pb (zircon): 216 MaRe-Os (molybdenite): 210-215 MaABCDQuesnel River faultGLFConnector FaultPinchi-Sawmill faultNF 8Cache CreekQuesnelFraser River fault NF 6F 10S2T: <450ºCD 1North-directed ductile thrusts (e.g., GraniteLake Faults (GLFs); NW-striking dextral faults (e.g., North Fault (NF) 8); NNE-trending sinistral faults (e.g., Connector Fault)Ar-Ar (white mica): 56-34 MaCW-rotation of D  structures; NE-strikingextension faults (e.g., Fault (F) 10); NW-SE extension (S  )  ; N-S trending dextral faults (e.g., North Fault (NF) 6)12D2Sinistral and/or west-side down fault displaces the Quesnel terrane (Schiarizza, 2014)R1R 2Nσ1σ1Pinchi faultσ3σ3R 1R2NFraser River faultσ1σ1σ3σ3Poles to S1Poles to D1 ductile thrust faults Pole to Fault 10Poles to S2Poles to dextral faults ± normal displacementPoles to East FaultsFold axes related to D1 ductile thrust faultsLineations associated with D2Stereograph Legend163Figure 2.50 Schematic maps of the main regional deformation events affecting the Granite Mountain batholith (GMB) and their relative timing. A. Formation of the GMB, and subsequent porphyry mineralization emplacement. Possible thrusting of the Cache Creek Complex over the Quesnel terrane(?). B. NNE-striking sinistral strike-slip fault used on a fault to explain the structural model. C. Progressive deformation forms D1 structures that are associated with regional NW-striking dextral strike-slip Pinchi fault, and the Quesnel River fault. Smaller, pit-scale faults cut the Gibraltar porphyry and offset ductile thrusts and the orebody. D. D2 associated with the Fraser River fault system thus continuing clockwise-rotation of the GMB and D1 structures. New NNW-trending dextral strike-slip and NW-trending extensional faults cut the Gibraltar porphyry and D1, and reactivate several earlier structures. Purple: Cache Creek terrane; Green: Quesnel terrane. Bold lines represent active faults; dashed lines represent faults that may or may have not been reactivated. Regional-scale fault concept modified after Schiarizza (pers. comm.). Present day Gibraltar pits are outlined in yellow. Stereographs depicting Pinchi (C) and Fraser (D) fault orientations and their associated stress regimes and fault trends that may be observed in Gibraltar Mine and the region (red). Black symbols represent different structures described in this study for comparison; modified after Campbell (2013). 164Construction of the Quesnel arc took place in the Middle Triassic to Early Jurassic, including intrusion of GMB (and associated Cu-Mo porphyry mineralization) in the western part of arc (Schiarizza, 2015). The Quesnel arc is interpreted to have formed along or near the western Laurentian margin (i.e., ancestral North America). The Cache Creek ocean was subducting eastward to generate the arc magmatism responsible for the formation of the Quesnel arc (Figure 2.50A). In the early Jurassic, parts of the Quesnel arc (including the GMB) were uplifted. Schiarizza (2015) mapped the Lower to Middle Jurassic Dragon Mountain succession (slate, siltstone, and sandstone) lying unconformably over the GMB. Tipper (1978) suggests that tonalite clasts in the Dragon Mountain succession came from GMB, and Barker and Grubisa (1994) show Dragon Mountain rocks deposited above the GMB in drill core obtained from near the north end of the batholith). These observations suggest that a part of the GMB must have been uplifted to surface level and then was subsequently reburied under the Dragon Mountain Succession. It is entirely possible that only the upper levels of the GMB were exposed to surface, and subsequently became incorporated into the conglomerate. The actual mineralized Mine Phase tonalite may well have still been located at depth (4 km would not be unrealistic) while the upper portions of the batholith were exposed at surface.In the Lower to Middle Jurassic, the Quesnel terrane, with the GMB, was thrust eastward over North American rocks. This contractional event represents the accretion of Quesnel terrane to ancestral North American (e.g., Gabrielse et al., 1992).  Closure of the Cache Creek ocean occurred in the Middle Jurassic and is represented by the arrival of Stikine terrane to the west. Contractional deformation during this event is represented by southwest directed thrusting within Cache Creek terrane and of Cache Creek terrane thrust over Stikine terrane. The boundary between the Quesnel and Cache Creek terranes, at this time, is unclear but represented by the Pinchi fault in some localities (Gabrielse et al., 1992). There is little data available to document deformation in the Late to middle Jurassic to late Early Cretaceous. Known intrusive rocks during this time period include Jurassic granitic intrusions at 160-168 Ma; and Early Cretaceous granitic at ~108 Ma (including the Sheridan Creek pluton).In the late Early Cretaceous to mid-Cretaceous significant contractional deformation occurred in the Bowser Basin to the northwest and in the southern Coast belt to the SW (Evenchick, 1991; 165Journeay et al., 1992). Significant sinistral faulting along Pasayten fault to the south is linked with contractional structures (Hurlow, 1993). Schiarizza (2014; 2015) has suggested that a north trending fault, with apparent sinistral offset, separates the GMB and other Quesnel rocks from Cache Creek to the east (Figure 2.50B, and refer to regional geology map in Figure 2.49) and may have been active during this time (at the earliest). In addition, this is the earliest time for activation of the south-dipping faults along the southern margin of the GMB (i.e., within the 108 Ma Sheridan Creek pluton; Figure 2.49) and for a northeast-striking Sheridan fault located along the southeastern margin of GMB (Figure 2.49).In the Early and Middle Eocene, possibly extending back into the Late Cretaceous, there are well-documented, major, NW-striking dextral faults, across the Cordillera that are locally linked to extensional faults that exhume metamorphic core complexes (Struik, 1993). The Wolverine, Vanderhoof, Tatla Lake, Mission Ridge-Shulaps, and Cayoosh metamorphic complexes are examples (Friedman and Armstrong, 1988; Coleman and Parrish, 1991; Struik, 1993; Staples, 2009).Lastly, in the Late Eocene, north-striking dextral faults were active, such as the Fraser River fault system, that demonstrably cross cuts the NW-trending Yalakom fault system (e.g., Struik, 1993).I propose that most of the strain recorded at the Gibraltar Cu-Mo porphyry is related to deformation associated with displacement along the NW trending strike-slip faults (e.g., the southern continuation of the Pinchi Fault; the Quesnel River fault) and by the N-S trending Fraser River fault system. This interpretation is similar to that suggested by Campbell (2013; in-house report by BGC Engineering Inc.). 2.7.5 Structural Model for the Evolution of the Gibraltar Cu-Mo depositThe geometry and kinematics, along with the Eocene Ar-Ar (white mica) cooling ages, provide compelling evidence that all deformation within the Gibraltar porphyry is a result of dextral strike-slip fault systems that initiated as early as mid-Late Cretaceous and continued into the Oligocene. Here, a model is presented in which both regional and local structures (faults, folds, and cleavages) are placed into two separate stress regimes anticipated for 1) NW-trending dextral strike-slip faults (i.e., Pinchi fault system; Figure 2.50C), and 2) N-S trending dextral strike-slip faults (i.e., Fraser River fault system; Figure 2.50D).166The NW-striking, dextral, Pinchi fault marks the boundary between Cache Creek terrane to the west and Quesnel terrane to the east. The mapped trace of the Pinchi fault ends about 50 Km northwest of the Gibraltar deposit (Figure 2.49). The fault has ~200 km displacement accumulated during the mid to Late Cretaceous and possibly into the Paleocene (Gabrielse et al., 2006; Wyld et al., 2006). Bailey (1990) interprets the Quesnel River fault to be a strand of the Pinchi fault. However, this fault is located within Quesnel terrane; it is not a terrane bounding structure. The Sawmill fault may separate the Cache Creek terrane from the Quesnel terrane, is located just SW of the GMB (Figure 2.49). This fault, if projected beneath the Miocene basalts, would separate the GMB from Cache Creek to the west, before it is truncated by a N-S striking fault, interpreted to be strands of the Fraser River fault system (pers. comm. with P. Schiarizza). In the model outline below, the Sawmill fault is considered the offset equivalent to the Pinchi fault system. 2.7.5.1 Structures Related to the Pinchi Fault SystemA strain ellipse illustrating the orientation and kinematics of structures associated with a NW-trending, dextral strike-slip fault system is illustrated in Figure 2.50C. Thrust faults would form striking E-W, in the orientation of the D1 thrust faults (e.g., GLFs and imbricates) located in the eastern half of the deposit (i.e., Granite Lake and Pollyanna pits; refer to geology map in Figure 2.4). Folds, with E-W trending fold axes would be anticipated in this strain regime as would a southerly dipping cleavage (i.e., S1). NNW-trending strike-slip faults are located northeast of the deposit, in the trondhjemite and Nicola-Takla Groups (1:50,000 map; Ash et al., 1999). These faults demonstrably offset NE-striking faults, as mapped by Ash (1999), and they are best fit for the R1 orientation of the Riedel shear array, or possibly, oriented sub-parallel to the Pinchi fault system (stereograph in Figure 2.50C; for concept model refer to Figure 2.50C).  Schiarizza (2015) infers that an apparent sinistral fault bounds the GMB to the east. This fault was proposed to separate Quesnel terrane from Cache Creek terrane, and to explain the apparent sinistral offset of Cache Creek rocks (Figure 2.50B). However, this fault could have normal kinematics and be formed during movement on the Pinchi fault to accommodate normal displacement. 2.7.5.2 Structures Related to the Fraser Fault System The N-S dextral strike-slip fault movements are interpreted to be reactivated normal faults that formed during movement on the Pinchi fault system. It is possible (probable?) that some of 167these strike-slip faults formed during movement on the Fraser fault system. The NNE-striking, steeply dipping faults observed in the pits are in the correct orientation for R1 synthetic (dextral) displacement (Figure 2.50C). A large ENE-striking fault bounds the GMB to the southeast (Figure 2.49) and is in the correct orientation for a R2, antithetic, sinistral fault.  Notably, the thrust faults in the Gibraltar porphyry rotate progressively clockwise towards the west. That is, there is a general trend from E-W striking in the eastern pits, to NW-striking in the western pits (Figure 2.50D). In the model presented here, the pre-existing thrust faults (formed in association with movement along the Pinchi fault system) are mechanically rotated into the Fraser fault in a clockwise (dextral) kinematic. In the Granite Lake pit, the Granite Lake (GL) thrusts are segmented along strike into E-W striking and more NW-striking orientations.  Drill core observations in tandem with analyses using Leapfrog® Geo, indicates that segments of the GL thrusts are rotated clockwise adjacent to steeply dipping dextral strike-slip faults. This supports the role of the Fraser fault system in rotating thrust faults.  Likewise, the S1 cleavage also rotates clockwise to a more NW strike in the western pits. The NW- to NNE-trending, dextral normal faults contain a prominent dextral shear sense defined by dragged muscovite-folia, and quartz porphyroclasts. The phyllosilicate-rich cataclasites developed in the faults, contain shallowly SE-plunging lineations, which include: mineral lineations and slickenlines (LSS); fold axes (F2), crenulation lineations, and intersection lineations (LI) associated with crenulations that have a crenulation cleavage (S2). These S2, L2 and F2 fabrics appear to be the youngest fabrics on the property as they all form a bulls-eye distribution the stereonet (Figure 2.50D) and so have not been rotated post formation. The SE-plunging fabrics are proposed to have formed during NW-SE directed exhumation of the GMB, and rheologically weak layers, with a steep dip (e.g., high angle fault zones), were flattened vertically and extended horizontally to give rise to the fabrics (Figure 2.54D).  A few low-angle faults have shear bands indicating top-down to the south extensional kinematics. It is interpreted that the faults were initially thrust faults that have been reactivated as extensional faults. The orientation of these extensional faults (striking E-W, dipping S) does not easily fit into the strain regime as dictated by the proposed strike slip-faulting model. To explain this extension, it is possible that if fluid pressures were lithostatic during movement, very unfavourably 168oriented faults could have been reactivated (e.g., Sibson, 1990). Furthermore, extension, both orogen-parallel and orogeny-perpendicular was common in the Cordillera in the Eocene. For example, NW-SE extension, controlled by dextral strike-slip faults, was responsible for the exhumation of the Wolverine metamorphic complex, located NW of the GMB, and for the Mission Ridge- Shulaps, and Cayoosh Creek metamorphic complexes (Coleman and Parrish, 1991; Staples, 2009). Extension in these complexes is accompanied by strong NE-SW trending lineations. The top-down to the south extension along the low-angle faults at Gibraltar, is compatible with the development of the shallowly SE-plunging lineations, which suggest that there was NW-SE extension in the batholith (in agreement with other areas in the southern Cordillera). Most of the Ar-Ar cooling ages for ductile thrusts and low-angle normal faults with conflicting shear sense indicators suggest that white mica mineral growth occurs from 38 to 34 Ma. This range in time is associated with the activation of the Fraser River fault system, and it is probable that most faults would either be reactivated or rotated during movement on the Fraser fault system. In addition, all faults would be under a stress as a result of the Fraser fault system and would therefore provide good permeability pathways for fluid flow during deformation. This fluid flow may explain the range in Ar-Ar cooling ages for the fine-grained white mica. Fluid flow could be episodic depending on the distribution of stresses in the system. If the fluid were sufficiently hot (~>300°C) they may have locally reset the finer-grained mica (Ganguly and Tirone, 2009). The presence of clasts composed of GMB tonalite in the Early to Middle Jurassic Dragon Mountain Succession (e.g., Tipper, 1978) indicates that parts of the GMB must have been at surface in the Early Jurassic; the porphyry however, may have remained at depth. Microstructure observations indicate that temperatures during deformation were on the order of at least 300°–350°C. This implies that in the Late Cretaceous, during formation of the thrusts and other faults as a result of movement along the Pinchi fault system, the GMB was buried at least 10 km (assuming a 30°C/km geothermal gradient).How was the Granite Batholith buried to 10 km? Based on outcrop distribution, the Dragon Mountain Succession may be several (~3) kilometres thick, and this sedimentary succession would have overlain the GMB. How is the deposit buried another 7 km? Possibilities include: 1) the Cache Creek terrane may have been thrust over the batholith (as proposed by Ash et al., 1999), and/or 2) 169Eocene volcanics may have covered the area. Alternatively, the geotherm may have been elevated to ~40°C/km as a result of extension, similar to that observed in extensional basins (e.g., Salton Sea, Death Valley; Bennett, 2011) which would require ~7.5 km burial depths. Also, Eocene volcanic rocks are ubiquitous in the region, and the underlying plutonic roots to the volcanoes may have contributed to the thermal budget required to heat the GMB. 2.7.6 Evidence for Ore Remobilization during Deformation Ankerite alteration is common in most ductile thrust faults and some ~N-S striking dextral, normal faults at Gibraltar. The ankerite is not porphyry-related; rather it was precipitated during fluid flow along the fault zones, related to deformation. Thus, most high strain zones are associated with ankerite. In addition, there is a known correlation between ankerite and elevated copper grades (Oliver, 2008). This suggests that the chalcopyrite was remobilized in fault zones as a result of fluid flow during Late Cretaceous to Eocene deformation, either by passive enrichment and suggested by Raffle (1998), or active precipitation (as is observed in quartz porphyroclasts pressure fringes).Additionally, chalcopyrite forms in brittle fractures that cut pyrite in sulphide blebs that occur in QSM veins, and may have formed similarly within BQ veins. 2.7.7 Structure as a Guide to Exploration for more OreGenerally, an increase in strain is associated with copper-molybdenum mineralization. QC and AQ alteration assemblages are good indicators of ductile shear zones and ore mineralization. To a lesser degree, QSC-QS-QSP (sericitic) alteration is associated with zones of high strain, and possibly ductile thrusts that contain strong mineralization, but may also be barren. The sericite in the QS and QSC alteration assemblages may not be entirely related to porphyry related hydrothermal fluids, and is likely partially related to fluid flow during later fault activation and reactivation. If the crystallinity and composition of this sericite is classified, a new method for mapping structure and ultimately ore, can be developed.Four different zones are proposed and highlighted for exploration targets in Figure 2.49. 1) Pit-scale ductile shear zones (e.g., GLF) contain and bound the orebodies, and therefore exert a first-order control on ore distribution (Oliver et al., 2009). The amount of offset along 170the thrust faults (both pit-scale and imbricates) is not well quantified and estimates range from 100’s to thousands of metres (Oliver, 2006; van Straaten et al., 2013). The S-SW of the orebodies undoubtedly presents potential for ore at depth, down dip of the thrust fault system where there is limited diamond drill hole data. Drill hole data does not exceed ~350 metres vertical depth, where, according to historical drill core geology logs, leucocratic phases were intersected. These rocks may be interpreted as another barren zone located between imbricate thrusts, potentially holding ore in the hanging wall. Ash et al. (1999) presented ore mineralization data in the hanging wall of a fault that separates the GL orebody; however, it is unclear whether a NE-striking normal fault (Warren Fault?) or a ductile shear zone (or both?) have displaced the ore. The southern contact of the Mine Phase tonalite south of the Granite Lake pit is ~2.5 km away, which leaves a lot of space to hold potential ore. 2) Recent work in the “Connector” pit, located between Gibraltar East and Pollyanna, and the northwestern part of the GL pit, shows elevated total copper grades (van Straaten et al., 2014). The copper mineralization in this zone seems to align with the Pollyanna orebody on an E-W trend. This E-W trend continues west of the CF as the Gibraltar East orebody and is rotated into a NE-trend that is limited in exploration beyond this orebody. This E-W trend is essentially mimicked to the south by the Granite Lake orebody that has an uncertain continuation in the west wall of the Connector Fault, and can be loosely interpreted to be continued by the Gibraltar West orebody. Ash et al. (1999) and Oliver et al. (2009) reported relatively low-grade mineralization in this area. Therefore, the western continuation of the Granite Lake orebody in the west-wall of the CF is unaccounted for and should not be displaced by more than 300 metres at depth, given other high-angle brittle fault displacements. Although there is limited diamond drill core data from the Connector area, these findings test previous hypotheses proposed by Drummond et al. (1976) and Bysouth et al. (1995) of a barren “core”, characteristic of most Cu porphyry systems. Nevertheless, this still leaves a barren zone in the hanging wall of the Granite Fault onto the Pollyanna orebody. Oliver (2006) suggested that the “barren zone” was a result of thrusting of the GL orebody along the Granite Fault onto the Pollyanna orebody. This study supports this interpretation, as these ductile thrust faults typically form along lithologic boundaries. Thus, a barren core may still lie beneath the Granite Lake orebody to the north, but more data is required from to produce a cohesive geologic model. 171Recent mapping by Schiarizza (2015) show the Mine Phase tonalite-Granite Mountain Phase trondhjemite contact trends: 3) ~1 km east-southeast of the GL pit, and 4) south-southeast of the GL pit, for ~5 km, both of which are offset by strike-slip faults and are discussed in detail below. If the orebody continues to conform to the orientation of the lithological contacts, the orebody immediately to the east of the GL pit should also shift in orientation. 3) The area located just east-southeast of the GL pit, is located in the hanging wall of the Saddle Fault (SF) which contains (<61 metres of east wall-down separation). The East Boundary Fault (EBF), located east of SF contains an unknown amount of offset in this zone, but is likely considerable. Lastly, the Warren Fault is extrapolated just west of this zone and immediately to the east of Granite Mountain, assuming it is the location of a leucocratic core that may control faults. The Warren Fault, assuming similar kinematics to Fault 10, should upthrow ore mineralization ~60 metres in the east wall, essentially cancelling-out the SF displacement. The "Gunn" mineral occurrence is also located here, and comprises sheeted pyrite-chalcopyrite-chlorite-sericite veinlets and a QSM vein (Cannon, 1968; Eastwood, 1970). The eastern continuation of the Cu-Mo zone of may also reside in this location (refer to Bysouth et al., 1995). 4) The area south-southeast of the GL pit should host the eastern continuation of the GL and Pollyanna orebodies. This estimation includes ~750 metres of apparent right-lateral displacement along the EBF. Thus, this proposed region likely contains the most potential for the location of an orebody. At a larger-scale, the timing and geochemistry of the Guichon Creek pluton, and related Late Triassic to Early Jurassic Highland Valley Cu-Mo (HVC) porphyry system are very similar to the calc-alkaline GMB and Gibraltar Cu-Mo porphyry emplacement. Therefore, there is a strong possibility for other porphyry-hosting plutons that may by unexposed beneath Tertiary and Quaternary deposits along an interval described as the “western Late Triassic calc-alkaline plutonic belt” (Schiarizza, 2014). Only two large deposits lie across this 150 km interval where two other parallel trends to the east comprise both alkalic Cu-Au deposits and granodiorite-hosting calc-alkaline Cu-Mo deposits that are essentially adjacent to each other, and match surprisingly well with HVC. Potentially, unexposed large calc-akaline Cu-Mo porphyry deposits with similar burial histories to the Gibraltar porphyry system may have not been exhumed to the same extent as Gibraltar.  172Chapter 3 Conclusions3 1 ConclusionsAr-Ar (white mica) cooling ages ranging from ~54 to 36 ± 5 Ma for S1, imbricate ductile thrust faults and a NE-dipping conjugate, and a N-S trending, dextral normal fault, suggest that all deformation took place in the Paleocene-Eocene. It is proposed that deformation is directly related to movement along the Quesnel River fault and Fraser River fault systems. However, the earliest formed fabrics (i.e., the main foliation (S1, and associated ductile thrust faults) may have formed during the hydrothermal alteration (i.e., 215-210 Ma). A crystallization age of 216.17 ± 0.24 Ma (U-Pb, zircon) was determined for the Mine Phase tonalite intrusion of the Granite Mountain batholith. Alteration assemblages were used as a proxy for units to map structure. Despite the high intensity of deformation within intrusive rocks, this was an effective technique for identifying deformation intensity, ductile thrust faults, ~N-S striking dextral faults ± normal displacement, and variably striking low-angle normal faults. Displacement values for high-angle dextral faults ± normal displacement and low-angle extension faults were determined. Strain intensity generally increases towards the main orebody over the scale of 10’s to 100’s of metres (pit-scale). Locally, the foliation is highly variable and increases in proximity to shear zones, faults, and sericitic alteration. Quartz-sericite ± chlorite (QSC-QS) alteration and boudinaged quartz (BQ) veins are associated with zones of high strain. Ductile thrust faults are associated with quartz-chlorite (QC) and ankerite-quartz (AQ) alteration assemblages, and QC alteration is strongly associated with ore mineralization.The structures were divided into two deformation ‘events’, D1 and D2; however, the structures probably formed in the same stress field in a progressive deformation. D1 - a variably intense but pervasive foliation (S1) is openly folded (F1) by a large (15-25 metre thick) and smaller-scale (<3 metres thick), shallow (20-25) to moderately (40-55) N- to NE-vergent imbricate ductile thrust fault system. Based on the relative size of the Gibraltar porphyry system and each orebody (e.g., GL), the magnitude of displacement is suspected to be at most 100’s of metres 173and less than 1 km.D2: NW- to NNE- (N-S) trending dextral faults ± normal displacement with foliated cataclastic fabrics cross cut and offset D1 and the orebody.A variably intense sub-horizontal crenulation cleavage (S2) is associated with moderate- to high-angle phyllosilicate-rich faults. F2 is parallel to fold axes of inclined tight folds (FQSM in quartz-sericite-molybdenite (QSM) veins), mineral lineations and slickenlines (LSS), and intersection lineations (LI).  NW-SE extension associated with D2 resulted in the formation of NE-striking low-angle normal faults (e.g., Fault 10) and reactivation of earlier structures. Several of the step-heating plateaus indicate minimum cooling ages that have been reset. Nevertheless, they provide insight in the extent of Eocene (or as early as Late Cretaceous) related faulting, and temperatures associated with fluid flow during fault movement. Several observations suggest that pervasive penetrative strain and associated ductile thrust faults post-date porphyry intrusion:1. Undeformed plagioclase in high strain zones indicate that the temperature of deformation was <450°C. Dynamic recrystallization of quartz indicates temperatures of at least 300°-350°C.2. The Sheridan pluton (ca. ~108 Ma) is in sheared contact with the southern border of the GMB (Schiarizza, 2014). The orientation and kinematics of the shear zone are the same as the GLFs of the imbricate ductile thrust (Granite Creek) system.3.  The earliest tectonic fabric (S1), in one sample cross cuts mineralized veinlets. 4. The Ar-Ar cooling ages (54 to 36 ± 5 Ma) indicate much younger deformation.Although the absolute timing of D1 is inconclusive, my data suggests that the microstructures are not commensurate with the foliation forming during intrusion and cooling of the GMB (i.e., a syntectonic intrusion).3.2  Recommendations for Future Work Structural analysis of the GL pit has provided the framework for a structural model that is supported by features in other pits and the regional structural geology. However, a much more 174detailed analysis of the entire mine area is necessary to build a true deposit-scale model. For instance, the use of oriented drill core is strongly suggested to gain more accurate measurements of veins/veinlets, foliation, and fault data down hole. Despite being a more efficient method for orientation analysis, the difficulty with oriented drill core is its high cost. Nevertheless, a thorough vein and veinlet geometric analysis using the vein/veinlets described within this thesis would allow a proper reconstruction of the early structures at Gibraltar porphyry, similar to Houston and Dilles (2013) who were able to infer two specific sets of veins geometries. One vein set was associated with early porphyry emplacement under a ductile shear strain at relatively deep depths, and the other a later, conjugate set associated with cooler temperatures in the porphyry fluids during normal faulting.  Fluid inclusion analyses on quartz should be conducted to constrain temperature, pressure, and compositional variation in fluids during the emplacement of the porphyry and during deformation events. Several analytical techniques (microthermometry, Raman spectroscopy, trace element analysis using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), and analyses of fluid inclusion solutes, gases and noble gases isotopes) were conducted by Rusk et al. (2008) for the Butte Cu porphyry system with their results aligning with relatively deep depths (6-9 km), high temperatures (575°-650°C) and pressures between 200 and 250 MPa. These specific analyses may also chemically distinguish any post-porphyry veins (i.e., BQ veins) associated with deformation and provide insight on the geothermobarometers during the earliest deformation event. This analysis could have direct implications on the mechanisms necessary for chalcopyrite crystallization and/or remobilization. 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Wyld, S.J., Umhoefer, P.J. and Wright, J.E., 2006; Reconstructing northern Cordilleran terranes along known Cretaceous and Cenozoic strike-slip faults: Implications for the Baja British Columbia hypothesis and other models: In Haggart, J.W., Enkin, R.J. and Monger, J.W.H., eds., Paleogeography of the North American Cordillera: Evidence For and Against Large-Scale Displacements: Geological Association of Canada, Special Paper 46, pp. 277–298. 190Appendix A Structural Field Data191Appendix A (cont) Magmatic Foliation: SMObject ID Easting Northing Location Strike/Dip Strike Dip IntensityFoliation 549428 5817984 Granite West 232/40 E 52 40Foliation 549311 5817960 Granite West 019/35 19 35Foliation 549311 5817960 Granite West 085/36 85 36Foliation 549166 5817943 Granite West 070/5 SE 70 5Foliation 549166 5817943 Granite West 085/4 N 265 4Foliation 549166 5817943 Granite West 085/5 N 265 5Foliation 549127 5817934 Granite West 130/72 130 72Foliation 548979 5817885 Granite West 220/6 N 220 6Foliation 549155 5817841 Granite West 162/08 162 8Foliation 549457 5817819 Granite West 43/21 SW 223 21Foliation 549429 5817856 Granite West 153/10 E 333 10Foliation 549396 5817857 Granite West 070/5 N 250 5Foliation 549377 5817862 Granite West 50/15 S 50 15Foliation 549355 5817858 Granite West 34/24 SE 34 24Foliation 549318 5817859 Granite West 102/18 S 102 18Foliation 549275 5817849 Granite West 062/10 N 242 10Foliation 549240 5817854 Granite West 095/2 N 275 2Foliation 550427 5817431 Granite East 065/25 65 25 weakFoliation 550772 5817472 G4E 045/25 SE 45 25 weak Foliation 550794 5817480 G4E 030/20 30 20Foliation 546902 5818487 Gibraltar West 151/51 151 51 Mod-strong192Appendix A (cont.) Foliation S1Object ID Easting Northing Location Strike/Dip Strike Dip IntensityFoliation 549283 5817949 Granite Lake West 125/75 125 75Foliation 549236 5817950 Granite Lake West 070/30 70 30Foliation 549236 5817950 Granite Lake West 146/52 146 52Foliation 549236 5817950 Granite Lake West 140/18 140 18Foliation 549113 5817929 Granite Lake West 125/15 SW 305 15Foliation 549113 5817929 Granite Lake West 140/64 140 64Foliation 549415 5817856 Granite Lake West 062/~0 62 9Foliation 549396 5817857 Granite Lake West 115/10 115 10Foliation 549396 5817857 Granite Lake West 000/35 E 0 35Foliation 549307 5817856 Granite Lake West 140/45 SW 140 45Foliation 549307 5817856 Granite Lake West 146/65 146 65Foliation 549275 5817849 Granite Lake West 118/29 S 118 29Foliation 550635 5817384 Granite Lake East 060/85 60 60 strongFoliation 550767 5817457 Granite Lake East 085/23 S 85 23 strongFoliation 550837 5817559 Granite South (East) 095/45 95 45Foliation 550720 5817674 Granite South (East) 032/6 32 6Foliation 549995 5817307 Granite Lake East 038/85 S 38 85Foliation 549984 5817352 Granite Lake East 232/34 232 34Foliation 549982 5817392 Granite Lake East 294/5 N 294 5Foliation 550109 5817506 Granite Lake East 294/64 294 64Foliation 550109 5817506 Granite Lake East 300/55 300 55Foliation 549772 5817025 Granite Lake West 113/17 SW 113 17 strongFoliation 546916 5818526 Gibraltar West 136/36 136 36 strongFoliation 546916 5818526 Gibraltar West 136/22 136 22 weak-modFoliation 546913 5818526 Gibraltar West 290/40 S 110 40Foliation 546893 5818487 Gibraltar West 155/32 155 32Foliation 546893 5818487 Gibraltar West 270/35 270 35Foliation 546888 5818465 Gibraltar West 137/35 137 35193Object ID Easting Northing Location Strike/Dip Strike Dip IntensityFoliation 546875 5818444 Gibraltar West 166/24 166 24Foliation 546865 5818433 Gibraltar West 295/20 N 295 20Foliation 546865 5818433 Gibraltar West 305/40 S 125 40Foliation 546865 5818433 Gibraltar West 305/38 S 125 38Foliation 546865 5818433 Gibraltar West 290/12 S 110 12Foliation 546864 5818425 Gibraltar West 320/56 320 56Foliation 549558 5819039 Pollyanna 140/42 NE 320 42Foliation 549534 5819022 Pollyanna 050/53 50 53Foliation 549445 5818969 Granite Lake West 120/85 E 120 85Foliation 549445 5818969 Granite Lake West 064/26 64 26 moderateFoliation 549445 5818969 Granite Lake West 286/26 286 26Foliation 549440 5818969 Granite Lake West 290/42 290 42Foliation 549409 5818957 Granite Lake West 015/20 E 15 20 moderate-strongFoliation 549409 5818957 Granite Lake West 080/0 80 0 moderate-strongFoliation 549373 5818931 Granite Lake West 110/44 110 44 moderate-strongFoliation 549373 5818931 Granite Lake West 104/34 104 34Foliation 549339 5818903 Pollyanna 044/38 44 38Foliation 549339 5818903 Pollyanna 092/39 92 39Foliation 549339 5818903 Pollyanna 132/42 132 42Foliation 549339 5818903 Pollyanna 070/40 E 70 40Foliation 549339 5818903 Pollyanna 225/55 E 45 55Foliation 549322 5818880 Pollyanna 076/11 76 11 strongFoliation 549322 5818880 Pollyanna 060/20 60 20Foliation 549295 5818831 Pollyanna 292/9 292 9 moderateFoliation 549295 5818831 Pollyanna 015/34 15 34 moderateFoliation 549295 5818831 Pollyanna 009/32 9 32 moderateFoliation 549293 5818831 Pollyanna 185/30 W 185 30 moderateFoliation 549293 5818831 Pollyanna 280/10 280 10 moderateFoliation 549293 5818831 Pollyanna 195/9 W 195 9 moderate194Object ID Easting Northing Location Strike/Dip Strike Dip IntensityFoliation 549293 5818831 Pollyanna 293/9 293 9 moderateFoliation 549278 5818804 Pollyanna 087/26 87 26195Appendix A (cont.) Fold Axes Object ID Easting Northing Plunge-Trend Plunge Trend Location Associated Fault Type of foldFold Axis 549384 5817970 42 -->196 42 196 Granite Lake West Dextral Strike-slipFold Axis 549356 5817966 28 --> 010 28 10 Granite Lake West Dextral Strike-slipFold Axis 549335 5817958 20 -->135 20 135 Granite Lake West Normal oblique(?)Fold Axis 549303 5817959 3 -->120 3 120 Granite Lake WestFold Axis 549283 5817949 21 -->135 21 135 Granite Lake West Normal oblique(?)Fold Axis 549265 5817950 25 -->135 25 135 Granite Lake West Strike-slipFold Axis 549181 5817943 20(?) -->014 20 14 Granite Lake WestFold Axis 549113 5817929 6 -->142 6 142 Granite Lake West Thrust fault (125/25)Fold Axis 549009 5817888 shallow plunge -->130 0 130 Granite Lake West N/AFold Axis 550818 5817629 ?-->125 125 Granite South (East) Open foldFold Axis 550803 5817676 14 -->134 14 134 Granite South (East)Fold Axis 550720 5817674 16-->131 16 131 Granite South (East) Fault(025/50)Fold Axis 546916 5818526 ?-->305 305 Granite West (lower)Fold Axis 546865 5818433 5-->085 0 85 Granite West (lower)Fold Axis 549558 5819039 6-->130 6 130 Pollyanna Thrust fault (158/50) Open foldFold Axis 549558 5819039 6-->135 6 135 Pollyanna Thrust fault (158/50) Open foldFold Axis 549558 5819039 26-->350 26 350 Pollyanna Thrust fault (158/50)Fold Axis 549534 5819022 4-->132 4 132 Pollyanna Both gentle/open and isoclinal folds are observed.Fold Axis 549445 5818969 3-->290 3 290 Granite Lake West 125/85Fold Axis 549373 5818931 15-->110 15 110 Granite Lake WestFold Axis 549334 5818903 12-->100 12 100 PollyannaFold Axis 549305 5818856 10-->130 10 130 PollyannaFold Axis 549278 5818804 6-->320 6 320 Pollyanna196Appendix A (cont.) LineationsObject ID Easting Northing Plunge-Trend Plunge Trend Loation Associated StructuresIntersection Lineation 549446 5818000 24 --> 061 24 61 Granite Lake WestIntersection Lineation 549265 5817950 5 -->130 5 130 Granite Lake WestIntersection lineation (not known of what)Intersection Lineation 549097 5817917 8 -->065 8 65 Granite Lake WestIntersection lineation- corrigation?Intersection Lineation 549009 5817888 shallow plunge -->130 0 130 Granite Lake WestIntersection Lineation 549396 5817857 25(?) -->140 25 140 Granite Lake WestIntersection between foliation (115/10) and CHLSULPH vein surface (310/60 S)Intersection Lineation 549396 5817857 13 -->140 13 140 Granite Lake WestIntersection between foliation (115/10) and CHLSULPH vein surface (310/60 S)Intersection Lineation 549396 5817857 9 -->147 9 147 Granite Lake WestIntersection lineation. Intersection Lineation 549534 5819022 30-->138 30 138 Pollyanna Vein material and fold by proximal fault (136/74)Intersection Lineation 549498 5819008 32-->115 32 115 Granite Lake WestIntersection Lineation 549445 5818969 15-->110 15 110 Granite Lake WestIntersection lineation of large qtz-vein and fold in qtz-mo vein 'B'Intersection Lineation 549445 5818969 15-->110 15 110 Granite Lake WestIntersection lineation of qtz-mo vein and fold in fault 'A'Intersection Lineation 549445 5818969 26-->104 26 104 Granite Lake WestIntersection lineation within fault 'B'Intersection Lineation 549440 5818969 15-->110 15 110 Granite Lake WestIntersection lineation of fold and vein. High strain zone is folded with open foldsIntersection Lineation 549334 5818903 15-->114 15 114 Pollyanna Intersection lineation for (A): see figure 51. Within main locus of fault. 197Object ID Easting Northing Plunge-Trend Plunge Trend Loation Associated StructuresIntersection Lineation 549322 5818880 29-->070 29 70 Pollyanna Intersection lineation, folded around crenulation on the foliated surface. Intersection Lineation 549305 5818856 ?-->105 105 Pollyanna Intersection lineation; too high to get plunge. Mineral Lineation 546872 5818438 30-->160 30 160 Gibraltar WestLineation associated w/boudinsSlickensides 549428 5817984 18 --> 160 18 160 Granite Lake West Normal fault w/dextral movementSlickensides 549377 5817964 16 -->140 16 140 Granite Lake West Dextral strike-slipSlickensides 549166 5817943 15 -->135 SE 15 135 Granite Lake Weststrike-slip, dextralSlickensides 550813 5817512 5 -->155 S 5 155 Granite South (East)Steep (normal)Slickensides 550825 5817538 20 -->140 20 140 Granite South (East)Surface of fault with reverse movement. Slickensides 550720 5817674 16-->131 16 131 Granite South (East)198Appendix A (cont.) P veinletsObject ID Easting Northing Location Strike/Dip Strike DipCHLSULPH 549446 5818000 Granite Lake West 010/49 10 49CHLSULPH 549446 5818000 Granite Lake West 275/50 275 50CHLSULPH 549402 5817979 Granite Lake West 346/48 346 48CHLSULPH 549356 5817966 Granite Lake West 100/40 S 100 40CHLSULPH 549335 5817958 Granite Lake West 145/45 W 145 45CHLSULPH 550346 5817330 Granite Lake East 115/55 S 115 55CHLSULPH 550358 5817330 Granite Lake East 115/65 115 65CHLSULPH 550369 5817340 Granite Lake East 125/45 125 45CHLSULPH 550376 5817342 Granite Lake East 110/45 S 110 45CHLSULPH 550385 5817354 Granite Lake East 110/70 S 110 70CHLSULPH 550388 5817375 Granite Lake East 090/64 E 90 64CHLSULPH 550430 5817435 Granite Lake East 094/60 94 60CHLSULPH 550423 5817441 Granite Lake East 030/80 S 30 80CHLSULPH 550414 5817453 Granite Lake East 120/68 120 68CHLSULPH 550767 5817457 Granite Lake East 140/21 S 140 21CHLSULPH 550785 5817471 Granite Lake East 120/80 120 80CHLSULPH 550794 5817480 Granite Lake East 030/20 30 20CHLSULPH 550837 5817583 Granite South (East) 120/48 120 48CHLSULPH 550829 5817605 Granite South (East) 105/51 SE 105 51CHLSULPH 550831 5817617 Granite South (East) 206/68 E 26 68CHLSULPH 548979 5817885 Granite Lake West 222/45 S 42 45CHLSULPH 549429 5817856 Granite Lake West 080/38 E 80 38CHLSULPH 549396 5817857 Granite Lake West 100/65 S 100 65CHLSULPH 549396 5817857 Granite Lake West 310/60 S 130 60CHLSULPH 549396 5817857 Granite Lake West 147/70 SW 147 70CHLSULPH 549240 5817854 Granite Lake West 124/55 S 124 55CHLSULPH 549240 5817854 Granite Lake West 005/74 5 74CHLSULPH 550151 5817491 Granite Lake East 327/21 327 21199Object ID Easting Northing Location Strike/Dip Strike DipCHLSULPH 549749 5817034 Granite Lake West 130/2 W 130 2CHLSULPH 549737 5817053 Granite Lake West 034/38 34 38CHLSULPH 549543 5819030 Pollyanna 154/6 154 6200Appendix A (cont) FaultsEasting Northing Location Strike/Dip Strike Dip Dip DirectionReverse Dip-slip Strike-slip Description549250 5817850 Granite Lake West 204/18 W 204 18 Reverse Uncertaingouge549250 5817850 Granite Lake West 144/18 W 144 18 Reverse Uncertain7 m from station549113 5817929 Granite Lake West 125/25 SW 125 25 Reverse549318 5817859 Granite Lake West 148/25 W 148 25 Reverse Fault splay off thrust fault549355 5817858 Granite Lake West 134/26 W 134 26 Reverse UncertainPossible thrust fault but shallow dip549275 5817849 Granite Lake West 105/35 S 105 35 Reverse Probablegouge549267 5817853 Granite Lake West 138/36 W 138 36 Reverse Probablegouge549135 5817940 Granite Lake West 104/38 104 38 Reverse ProbableMal present549355 5817858 Granite Lake West 138/42 W 138 42 Reverse Probable? Mal present549396 5817857 Granite Lake West 183/44 183 44 Reverse ProbableHem-staining549097 5817917 Granite Lake West 118/50 118 50 Reverse Probable?549181 5817943 Granite Lake West 014/52 14 52 Uncertain Folded fault surface w/ boudinaged qtz vein at contact of NM13-008549415 5817856 Granite Lake West 164/54 E 344 54 Uncertain 3m from station549265 5817950 Granite Lake West 134/62 134 62 ? Possible SS201Easting Northing Location Strike/Dip Strike Dip Dip DirectionReverse Dip-slip Strike-slip Description549429 5817856 Granite Lake West 335/70 E 335 70 SS549166 5817943 Granite Lake West 143/75 SE 143 75 Dextral SS549429 5817856 Granite Lake West 160/75 E 340 75 SS549377 5817964 Granite Lake West 352/78 W 172 78 Dextral SS549428 5817984 Granite Lake West 349/84 E 349 84 Normal Dextral Same as below549428 5817984 Granite Lake West 161/~84(?) 161 84 Normal Dextral Same as above549265 5817950 Granite Lake West 161/84 161 84 Normal Dextral549155 5817841 Granite Lake West 005/85 5 85 ? SS549402 5817979 Granite Lake West 348/~vert 348 90 SS549335 5817958 Granite Lake West 158/vert 158 90 SS549285 5817950 Granite Lake West 318/~vert 318 90  SS549265 5817950 Granite Lake West 025/~vert 25 90 SS549429 5817856 Granite Lake West 168/~vert 168 90 SS, 10m down from station549396 5817857 Granite Lake West 116/~vert 116 90 SS549250 5817850 Granite Lake West 200/~vert E 200 90 SS, 7m from station550411 5817396 Granite Lake West 264/85 E 264 85 Uncertain, Maybe E-W SS550411 5817396 Granite Lake West 098/80 (E?) 98 80 Uncertain, Maybe E-W SS550767 5817457 Granite Lake East 115/42 115 42 Reverse550782 5817471 Granite Lake East 338/18 SW(?) 158 18 Reverse550813 5817512 Granite South (East) 106/~vert[~78] 106 90 Uncertain, Maybe E-W SS550813 5817512 Granite South (East) 035/58 35 58 Reverse550813 5817512 Granite South (East) 125/35 S 125 35 Reverse550837 5817559 Granite South (East) 035/81 E(?) 35 61 Uncertain, Maybe SS202Easting Northing Location Strike/Dip Strike Dip Dip DirectionReverse Dip-slip Strike-slip Description550829 5817605 Granite South (East) 105/51 SE 105 51 Reverse550829 5817610 Granite South (East) 035/50 W 215 50 Reverse550765 5817669 Granite South (East) 140/51 S 140 51 Reverse Probable550720 5817674 Granite South (East) 025/50 E 25 50 Reverse ProbableHem-staining550135 5817491 Granite Lake East 056/44 SE 56 44 Reverse ProbableHem-staining549681 5817087 Granite Lake West 062/80 242 80 Late-Brittle546913 5818526 Gibraltar West 310/85 310 85 SS546888 5818465 Gibraltar West 270/15 270 15 Reverse Probable546872 5818438 Gibraltar West 340/54 340 54 Reverse ProbableQtz-vein549558 5819039 Pollyanna 115/58 115 58 Reverse549558 5819039 Pollyanna 338/44 338 44 Reverse Normal Reactivated Reverse Fault, QSM vein549534 5819022 Pollyanna 136/74 136 74 SS, QSM vein549505 5819025 Pollyanna 140/14 140 14 Reverse Probable549498 5819008 Pollyanna 065/31 65 31 Reverse Probable549498 5819008 Pollyanna 090/78 S 90 78 E-W549464 5818983 Pollyanna 090/65 E 90 65 Normal Sinistral E-W  Late brittle549449 5818972 Pollyanna 270/22 270 22 ??sub-horiz fault?549445 5818969 Pollyanna 131/81 131 81 SS, QSM vein 549409 5818957 Pollyanna 360/~vert 360 90 Normal SS203Easting Northing Location Strike/Dip Strike Dip Dip DirectionReverse Dip-slip Strike-slip Description549339 5818903 Pollyanna 088/45 88 45 Reverse 5 m from station549339 5818903 Pollyanna 075/35 S 75 35 Reverse549322 5818880 Polyanna 110/22 110 22 Reverse Normal Reactivated Reverse Fault549312 5818618 Pollyanna 135/55 NE 135 55 Reverse Normal Reactivated Reverse Fault549305 5818856 Pollyanna 222/21 222 21 Reverse Normal Reactivated Reverse Fault549476 5817578 Granite Lake West 349/79 E 342 79 East Side downSS, Rainbow 8549458 5817626 Granite Lake West 347/90 W? 167 90 West side downSS, Rainbow 8549512 5817640 Granite Lake West 165/49 W 165 49 SS, Rainbow 9549512 5817640 Granite Lake West 155/80 155 80 West side downSS549594 5817636 Granite Lake West 231/80 W 231 80 SS549559 5817492 Granite Lake West 285/80 285 80 Late-Brittle549559 5817492 Granite Lake West 174/51 W 174 51 gg Rainbow 9204AGibraltar West: Looking towards 336˚307˚ 218˚127˚15.24 m150 m038˚NM-13-039NM-13-038 NM-13-037 NM-13-036Overburden166˚/24˚ 168˚/46˚ 090˚/15˚ 151˚/51˚310˚/85˚5˚315˚/21˚????B?Mineralized Not Mineralized ?Appendix A1 Gibraltar West 2950’ bench wall and strip map. A. Stitched photographs of the Gibraltar West 2950’ bench wall. NNW-trending, strongly oxidized, reddish-brown coloured, high-angle oblique-slip fault offsets the orebody in the Gibraltar West pit. B. Strip map of the Gibraltar West 2950’ bench wall. West-southwest dipping ductile shear zones (168/46 and 090/15) offset by a north-northeast trending oblique strike-slip fault. Small conjugate faults, some with normal shear sense, and others with boudinaged quartz veins, are observed in the south part of the bench wall dipping towards the NE, above sample NM-13-039 that was collected from a sub-horizontal to NE-dipping, low-angle shear zone (315/21).205Appendix B Sample Data206Appendix B (cont.) Hand Sample DataSample ID UTM E UTM N Location Measurement Description U-Pb Ar-Ar TSNM-13-001 549446 5818000 GL West: 3770'-3950' bench275/50 Propylitic vein surface (275/50). Bright pistachio-green coloured epidote (2-3 mm), <5% Quartz-eyes, 1-2 mm: 15% Plagioclase (yellow coloured) 2-4 mm: 35-45% Chloritized hornblende <1 cm: 35-45% Yes YesNM-13-002 549428 5817984 GL West: 3770'-3950' bench232/40 E S1Yes Yes (2)GL West: 3770'-3950' bench161/~84(?) Fault attitudeNM-13-003 549377 5817964 GL West: 3770'-3950' benchSample taken at western margin of dextral fault. qcT + ser altYesGL West: 3770'-3950' bench140 -->16 SlickensidesGL West: 3770'-3950' bench350/80 Fault plane attitude at western fault; west marginNM-13-004 549335 5817958 GL West: 3770'-3950' bench145/45 W Sample taken at western margin of fault YesGL West: 3770'-3950' bench158/vert chlorite-seamGL West: 3770'-3950' benchFault attitudeNM-13-005 549303 5817959 GL West: 3770'-3950' bench235/35 Fracture surface (may be fold hinge) Yes207Sample ID UTM E UTM N Location Measurement Description U-Pb Ar-Ar TSNM-13-006 549265 5817950 GL West: 3770'-3950' bench130/35NM-13-007 549265 5817950 GL West: 3770'-3950' bench145/90 YesGL West: 3770'-3950' bench25 →135GL West: 3770'-3950' bench134/62 Fault attitude. Possibly a strike-slip fault. No indicators of dip-slip componentNM-13-008 549208 5817946 GL West: 3770'-3950' benchLeucocratic tonalite. Sample contains less chl and an increase in qtz and plagYesNM-13-009 550344 5817329 GL East: 3350' bench115/65 Sample shows clear sheeted QC veinlets in one orientation. High % of veining with well mineralized veins and rock. Presence of both cp + py. QCT veins are 1 cm wideYes YesNM-13-010 550358 5817330 GL East: 3350' bench115/65 Sample taken of leucocratic porphyry tonalite with QC veinlet occurrence. Small specs of chl in otherwise massive qtz + plag rock GL East: 3350' benchAttitude of QSP veinletNM-13-011 550388 5817375 GL East: 3350' benchSample is massive-dT(?) with the presence of P veinlets containing py+cp. QC overprint is lost. No QC veinlets (or very few)GL East: 3350' bench090/64 E P veinletsNM-13-012 550411 5817396 GL East: 3350' benchFaults here have same orientation as previous location with measurement. Weak foliation is present and may possibly continue from hereGL East: 3350' bench098/80 (E?) Fault attitude. Weak foliation is present208Sample ID UTM E UTM N Location Measurement Description U-Pb Ar-Ar TSNM-13-013 550419 5817402 GL East: 3350' benchSample taken of cqyT. High mineralization veins. P+QC veinlets are observed. Disseminated? Weak foliationNM-13-014 550427 5817431 GL East: 3350' benchPossible qtz-vein with sheeted mo veinletsGL East: 3350' bench065/25 Sample showing weak magmatic foliationNM-13-015 550430 5817435 GL East: 3350' benchYesGL East: 3350' bench094/60 chlorite-seamNM-13-016 550423 5817441 GL East: 3350' benchHematite stained and cb present in rockGL East: 3350' bench030/80 S chlorite-seam; proximal to faultNM-13-017 550414 5817453 GL East: 3350' benchGL East: 3350' bench120/68 P veinlet; py+cp vein surfaceNM-13-018 550767 5817457 GL East: 3725' bench115/42 Fault surface; NE verging, dipping SW. Hem-stained + clays and ser(?) cuts off foliation of footwall. Hanging wall is massive deuteric to propylitically altered tonalite. P veinlets are observed  YesGL East: 3725' bench085/23 S Foliation surface of high strain zone (~1 m); contains qtz-eyes.GL East: 3725' bench030/70 W Fractured surface from the more ductile shear zone which conceals the foliated surface.GL East: 3725' bench140/21 S chlorite-seamNM-13-019 550772 5817472 GL East: 3725' benchP veinlets are abundant with sulph mineralization GL East: 3725' bench035/86 Fracture surface; use for re-orientating in the lab209Sample ID UTM E UTM N Location Measurement Description U-Pb Ar-Ar TSGL East: 3725' bench045/25 SE Weak magmatic foliationNM-13-020 550794 5817480 GL East: 3725' bench5m down bench from: fault splays (thin faults) appear to be sub-horizontalGL East: 3725' benchWeak foliationNM-13-021 550829 5817605 GL East: 3725' benchPossible slip along chlorite-seam. This fault may have formed more ductily, resulting in high strain zones on either sideYesGL East: 3725' bench105/41 SE Fault surface is similar to chlorite-seam attitudeNM-13-022 550829 5817605 GL East: 3725' bench110/?-Lori Yes5m N from last stationGL East: 3725' bench035/50 W FaultNM-13-023 550831 5817617 GL East: 3725' bench206/68 E P veinletGL East: 3725' bench203/6 SENM-13-024 GL East: 3725' benchNM-13-025 549166 5817943 GL West: 3770'-3950' benchJudging by the rotation of the foliation, it appears to be a dextral faultGL West: 3770'-3950' bench070/5 SE Surface foliation. Possibly Sm. In this locality, this rock is pervasively foliated. qcT-qcyT.210Sample ID UTM E UTM N Location Measurement Description U-Pb Ar-Ar TSGL West: 3770'-3950' bench085/4 N Inconsistent values for SGL West: 3770'-3950' bench085/5 N Inconsistent values for SNM-13-026a 549113 5817929 GL West: 3770'-3950' benchBottom of thrust fault with foliated mylonitic fabric. Sample was taken from the footwallYesGL West: 3770'-3950' bench125/25 SW FaultGL West: 3770'-3950' bench125/15 SW Strongly foliated fabricGL West: 3770'-3950' bench6 -->142 Fold axis of crenulation surface in footwall to faultGL West: 3770'-3950' bench149/55 NE Axial surface of crenulationGL West: 3770'-3950' bench140/64 Foliated fabricNM-13-026b549113 5817929 GL West: 3770'-3950' bench140/64 Footwall; gouge; QC alteration Yes YesNM-13-027 549155 5817841 GL West: 3770' benchSample taken from hanging wall.GL West: 3770' bench162/08 W Fault 211Sample ID UTM E UTM N Location Measurement Description U-Pb Ar-Ar TSGL West: 3770' bench005/85 Gouge material is steeply dipping. Gouge defines the dip of the fault. Everything else is just composite. No lineations (slickensides) or fabric to suggest any strike-slip movement. Therefore it is believed to be either normal or reverse. Malachite is present in gougeNM-13-028 549457 5817819 GL West: 3770' bench43/21 SW QC alteration rock with RQ (≤10cm) veins cross cutting the Sm foliation. Strongly foliated rock, with some veining along foliated planes. QC with magnetite is observedNM-13-029 549429 5817856 GL West: 3770' benchSample taken from gouge, includes a qtz-vein photo YesGL West: 3770' bench160/75 E FaultGL West: 3770' bench335/70 E FaultGL West: 3770' bench153/10 E Magmatic-foliationGL West: 3770' bench080/38 E chlorite-seamNM-13-030a 549396 5817857 GL West: 3770' bench310/60 S chlorite-seam YesGL West: 3770' bench25(?) -->140 Intersection between foliation (115/10) and chlorite-seam (310/60 S)GL West: 3770' bench13 -->140 Intersection between foliation (115/10) and chlorite-seam (310/60 S)GL West: 3770' bench116/~vert Fault #2GL West: 3770' benchSmall scale folds and crenulations are visible. Likely due to Fault #2 being a thrust fault.NM-13-030b549396 5817857 GL West: 3770' benchGood representation of intersection lineation. See figureGL West: 3770' bench140/70 SW Fracture surface. chlorite-seam212Sample ID UTM E UTM N Location Measurement Description U-Pb Ar-Ar TSGL West: 3770' bench9 -->147 Intersection lineation. GL West: 3770' bench000/35 E Phyllic material which wraps and boudins; qsp alteration rock. NM-13-031a 549240 5817854 GL West: 3770' benchSample taken from east side of heavily veined and moderate-strongly foliated zone of fault. YesGL West: 3770' bench124/55 S chlorite-seam fracture surface. NM-13-031b549240 5817854 GL West: 3770' benchSample taken from within high strain zone/fault zone. YesGL West: 3770' bench005/74 P veinlet folded enveloping surfaceNM-13-031c 549240 5817854 GL West: 3770' bench050/72 Fracture surface for re-orientation. YesNM-13-031d549240 5817854 GL West: 3770' benchSample taken from 5-6m away from UTM in west direction. Rock appears to be ycq, maybe dT(?). Barren veins are visible.YesGL West: 3770' bench095/2 N Magmatic-foliationNM-13-032 549995 5817307 GL East: 3300' benchA few metres WestGL East: 3300' benchNM-13-033 549974 5817417 GL East: 3300' bench15-20cm qtz-vein with mo+cp (BQ). Cp occurs as large blebs; mo occurs as thick (1cm)- thin (2mm) veinlets parallel to vein orientation. Yes YesGL East: 3300' benchMo in sampleGL East: 3300' bench282/~vert Qtz-vein attitude.GL East: 3300' benchVein is likely a late-mineralization-stage D-vein. 213Sample ID UTM E UTM N Location Measurement Description U-Pb Ar-Ar TSNM-13-034 549788 5817016 GL West: 3800' benchDeuterically altered Mine Phase tonalite from last station to this one. Massive with an indication of foliation. Almost fresh 2-3mm hbl crystals with euhedral-subhedral shape. Qtz and plag crystals are fresh, euhedral and 3mm in size. Moderate sausseritization with ep altering from plag. Some ep veinlets are present. Weak chloritization of hbl. Presence of sulphide mineralization with py and few cpGL West: 3800' benchRock type sample. Potential sample for U-Pb?NM-13-035 549742 5817053 GL West: 3800' bench027/27 Chl-fracture surface/vein surface/ enveloping surface. Uncertain value as orientation variesYes YesNM-13-036 546916 5818526 Gibraltar West: 2950' benchSample of cq-qsc (weak-moderately foliated) with sulphides Gibraltar West: 2950' bench147/55 Fractured surface for orientationNM-13-037 546893 5818487 Gibraltar West: 2950' benchFault movement direction is uncertain. Gouge material is grey/clayey with sericite5-6m West of Last StationGibraltar West: 2950' benchUpper contact of faultGibraltar West: 2950' bench137/35 Foliation surfaceNM-13-038 546864 5818425 Gibraltar West: 2950' bench320/56 Foliated surfaces (surface is variable)NM-13-039 546887 5818401 Gibraltar West: 2950' benchSample of high strain zone in bench below high strain zone has a general slope dipping towards east; and is shallowYes Yes214Sample ID UTM E UTM N Location Measurement Description U-Pb Ar-Ar TSGibraltar West: 2950' bench156/21 Enveloping surface of sample.Gibraltar West: 2950' benchSample contains folds indicating shallow confining thrust faultsNM-13-040a 549558 5819039 Polyanna: 3870' benchFault appears to crosscut 10m-wide folded zone. Fault and surrounding rock appear to have intersected during deformation. The footwall appears to be dragged down, while hanging wall is up. The veins in the fault are also folded suggesting pre-existing veins (possibly from an earlier fault), which may have been reactivated and caused folding in vein. Class 1 type foldYesPolyanna: 3870' bench140/42 NE NE side of major fault/QSM vein. yT. NM-13-040b549558 5819039 Polyanna: 3870' bench338/44 Fault attitude/QSM vein.Polyanna: 3870' benchLarge fault contains large qtz+py vein and folded qtz-mo vein and crosscuts entire folded package. Major fault is dipping north. Yes YesNM-13-041 549534 5819022 Polyanna: 3870' benchSample of strongly foliated country rock, proximal to yTPolyanna: 3870' bench045/20Polyanna: 3870' bench?-->154 Open folds NM-13-042 549445 5818969 Polyanna: 3870' benchSample taken from high strain fabric associated with fault 'B'YesPolyanna: 3870' bench286/26 Foliation of fault fabric within fault 'B'Polyanna: 3870' bench26-->104 Intersection lineation within fault 'B'215Sample ID UTM E UTM N Location Measurement Description U-Pb Ar-Ar TSNM-13-043a 549445 5818969 Polyanna: 3870' bench5m From Last StationPolyanna: 3870' bench110/11 South of moderate foliation with yqspT.NM-13-043b549373 5818931 Polyanna: 3870' bench104/34 Moderate-strong foliation of feldspathic Mine Phase tonalite rock.YesNM-13-044 549322 5818880 Polyanna: 3870' bench060/20 Sample taken of strongly foliated cqT with foliated surface of 060/20. Shear sense indicators may be present. Taken from just above large qtz-vein (fault), but within fault zone. Thrust (low-angle?)Yes Yes (2)216Appendix B (cont.) Drill Core Sample Data Sample ID Multiple Hole IDCollar E UTMCollar N UTMTrend Plunge Total Depth (ft)Total Depth (m)Depth (ft)Depth (m)Lithology Description TS Cross SectionNM-13-001 2007-098549236.3 5817491.1 350 88 1581 481.89 147.1 44.84 dT Fresh hbl for Ar-Ar geochronologyYes ~NM-13-002 2007-098549236.3 5817491.1 350 88 1581 481.89 421.7 128.53 aqTe BQ vein; qsTe with aqTe.~ ~NM-13-003 2007-098549236.3 5817491.1 350 88 1581 481.89 450.2 137.22 aqTe High strain zone with S2 fold axis.Yes ~NM-13-004 2007-098549236.3 5817491.1 350 88 1581 481.89 521.2 158.86 yT Mo(?) associated with Ep vein. ~ ~NM-13-005 2006-021548982.8 5817684.8 0 -90 1047 319.13 163.1 49.71 aqTe Qtz-lenses and boudins.~ ANM-13-006 2006-021548982.8 5817684.8 0 -90 1047 319.13 494.4 150.69 aqT Sericite alteration and mod-strong foliation with qsp vein (QSP)~ ANM-13-007 2006-021548982.8 5817684.8 0 -90 1047 319.13 535.7 163.28 yqspT QSP veinlets Yes ANM-13-008 2006-021548982.8 5817684.8 0 -90 1047 319.13 627.1 191.14 yqspT Late-stage QSM with mo.~ ANM-13-009 2006-021548982.8 5817684.8 0 -90 1047 319.13 649.8 198.06 cqyT QC with sulph centre and chl-halo.Yes ANM-13-010 2006-021548982.8 5817684.8 0 -90 1047 319.13 710.3 216.5 cqyT 2 QC veinlets, one with mo and one with mag. ~ ANM-13-011 2006-021548982.8 5817684.8 0 -90 1047 319.13 986.8 300.78 ycqT Foliated with qtz-lens; likely qtz-chl QC veinlet (barren).Yes ANM-13-012 2006-021548982.8 5817684.8 0 -90 1047 319.13 987.5 300.99 ycqT BQ vein with chl+py.~ A217Sample ID Multiple Hole IDCollar E UTMCollar N UTMTrend Plunge Total Depth (ft)Total Depth (m)Depth (ft)Depth (m)Lithology Description TS Cross SectionNM-13-013 2006-021548982.8 5817684.8 0 -90 1047 319.13 1037.3 316.17 acqT Qtz-lenses in foliated zone; qtz likely  QC (qtz-chl) barren.~ ANM-13-014 2006-028549277.9 5817654.1 0 -90 1192 363.32 94.7 28.86 dF Weak to trace foliation with fresh hbl.~ ~NM-13-015 a,b 2006-028549277.9 5817654.1 0 -90 1192 363.32 410.7 125.18 qspyT a: Vein with mo(?)+ep and sausseritized plag. B: sericite~ ~NM-13-016 2006-028549277.9 5817654.1 0 -90 1192 363.32 447.1 136.28 qspyT Apple-green sericite(?) ~ ~NM-13-017 2006-028549277.9 5817654.1 0 -90 1192 363.32 495.7 151.09 qspyT BQ vein+cb and boudins. ~ ~NM-13-018 2006-028549277.9 5817654.1 0 -90 1192 363.32 498.5 151.94 qspyT Veins and interesting cross cutting relationships.Yes ~NM-13-019 a,b,c 2006-028549277.9 5817654.1 0 -90 1192 363.32 697.5 212.6 qspyT BQ veins with boudins.~ ~NM-13-020 2006-028549277.9 5817654.1 0 -90 1192 363.32 700.1 213.39 qspyT P veinlet and foliation, and QSM/QC w/mo~ ~NM-13-021 2007-097548974.2 5817568.5 0 -90 1080 329.18 210.3 64.1 qsTe BQ vein ~ A; GNM-13-022 2007-097548974.2 5817568.5 0 -90 1080 329.18 225.7 68.79 qsTe Strong foliation and S1, S2 surfaces + crenulations.~ A; GNM-13-023 2007-097548974.2 5817568.5 0 -90 1080 329.18 365.8 111.5 qscyT Strongly foliated with S1, and S2. Yes A; G218Sample ID Multiple Hole IDCollar E UTMCollar N UTMTrend Plunge Total Depth (ft)Total Depth (m)Depth (ft)Depth (m)Lithology Description TS Cross SectionNM-13-024 2007-101549479.7 5817362.7 0 -90 1297 395.33 288.8 88.03 ydT Moderate-strong foliation to compare chl (alt) to chl (metamorphic deformation)Yes BNM-13-025 2007-101549479.7 5817362.7 0 -90 1297 395.33 381.1 116.16 aqTe Crenulations and folding with S1, S2 surfaces. ~ BNM-13-026 a,b,c 2007-101549479.7 5817362.7 0 -90 1297 395.33 460.1 140.24 dT a: Massive dT to compare with b, and c: Strongly foliated with chl (metamorphic deformation)~ BNM-13-027 a,b 2007-101549479.7 5817362.7 0 -90 1297 395.33 920.2 280.48 dT Fault zone with sericite. A: unfoliated; b: foliated~ BNM-13-028 2010-020549476.7 5817302.5 145 -70 863 263.04 491.3 149.75 qsTe Weak to moderate crenulations.~ BNM-13-029 2010-020549476.7 5817302.5 145 -70 863 263.04 589.8 179.77 cqT S1 and S2. ~ BNM-13-030 2010-020549476.7 5817302.5 145 -70 863 263.04 784.9 239.24 qscTe S1 and S2 of crenulation cleavage.~ BNM-13-031 2010-020549476.7 5817302.5 145 -70 863 263.04 829.2 252.74 yT Fault zone within yT; clayey and cb material.~ BNM-13-032 2011-001549850.9 5817278.0 329 -87 643 195.99 583 177.7 qspcT Fault zone with sericite.Yes D219Sample ID Multiple Hole IDCollar E UTMCollar N UTMTrend Plunge Total Depth (ft)Total Depth (m)Depth (ft)Depth (m)Lithology Description TS Cross SectionNM-13-033 2011-001549850.9 5817278.0 329 -87 643 195.99 622.1 189.62 qspcT Sericite, next to Re-Os date of mo taken by B.Harding 2011. ~ DNM-13-034 a,b 2012-001547945.2 5818678.9 265 -74 900 274.32 309.4 94.31 cqTe Strongly foliated and chl-qtz altered rock with possible folded P veinlet~ ~NM-13-035 a 2013-003548176.2 5819219.3 24 -63 1100 335.28 771.2 235.06 cqT Chl-qtz altered. QC vein: qtz-mag-py-cp+/-mo?. Sulph as blebs. Weak to trace foliation. ~ ANM-13-036 a 2013-004547161.1 5819584.8 254 -64 1198 365.15 1558.5 475.03 ycqT Moderately pale green sausuritized plag, overprinted by chl-qtz alteration; with 2-5mm mag vein and 0.1-2mm P vnlt cut by 3-10mm late white qtz veins. Thin hairline P veinlets locally highly abundant. Fine cp (0.7%) and py (1%) dis and associated with mag vein.Yes A; G220Sample ID Multiple Hole IDCollar E UTMCollar N UTMTrend Plunge Total Depth (ft)Total Depth (m)Depth (ft)Depth (m)Lithology Description TS Cross SectionNM-13-037 b 2013-005547634.6 5820082.9 98 -80 900 274.32 90.2 27.49 cqTe Sample 1a,b: Strongly foliated, partly crenulated, dark greenish grey with distinct interlayers of qtz and chl and associated py (Qtz-chl-sulph); strong qtz, weak chl with weak cb as thin coatings in qtz; py mainly as dis and fine-grained clusters along foliation planes (3%); with rare cp as fine specks (0.5%) and mo (0.1%) Sample 2a,b: Chl-qtz altered rock with abundant mag-qtz-sulph patches. Core cut parallel to qtz-mag vein?"~ A221Sample ID Multiple Hole IDCollar E UTMCollar N UTMTrend Plunge Total Depth (ft)Total Depth (m)Depth (ft)Depth (m)Lithology Description TS Cross SectionNM-13-038 2013-018549260.8 5817272 14 -45 1840 560.83 331.7 101.1 dT Foliated deuterically altered tonalite. S1 foliation cut by crenulation cleavage (S2). Abundant chl and ser forming foliation planes. Clear L1-2 intersection lineation presentYes GNM-13-039 a 2013-018549260.8 5817272 14 -45 1840 560.83 458.8 139.84 dT Deuterically altered tonalite with euhedral fresh hbl and ep altered hbl~ GNM-13-040 2013-018549260.8 5817272 14 -45 1840 560.83 539.3 164.38 qscFe Highly strained qsc altered feldspathic tonalite. S1 foliation is cut by S2 of fold.Yes G222Appendix C Petrographic Data223Sample ID: NM-13-001Textural Description: Two, folded, barren and dynamically recrystallized quartz veinlets with sharp vein margins cross cut a Mine Phase tonalite. Barren quartz veinlets are oblique to the moderate to weak foliation defined in hand sample by chlorite-sericite seams and elongate quartz and plagioclase grains. The main tectonic foliation is dipping towards the southwest and is dragged by the fault. No sulphides are present. Epidote alteration occurs as very fine-grained clusters after plagioclase. Sericite alters after plagioclase. Spatially, sericite is associated with chlorite and very fine-grained secondary quartz in the matrix. There is essentially no hornblende remaining after chlorite alteration.Minerals Modal (%) Size (mm) Primary Quartz 30 <1Secondary Quartz 20-25 <0.1Plagioclase 20-25 <0.2Hornblende 10-15 <0.4Epidote 15 <0.01Sericite 10 <0.001Chlorite 10 0.1-0.4Clinozoisite-zoisite 5 <0.1Structural Relationships:Elongate primary quartz augens and plagioclase grains are parallel to the main tectonic fabric. Sericite aligns parallel to the foliation. Epidote does not contain a preferred orientation. Primary quartz augens are observed with the formation of subgrains. Secondary, recrystallized quartz in the veinlets typically contains undulatory extinction. Location:Sample looks towards the west and was collected from the upthrown east wall of a dextral strike-slip fault (North Fault 8b).    ZX5 mmPPL XPL224Sample: NM-13-001 DDHTextural Description:Equigranular feldspathic Mine Phase tonalite contains relatively fresh plagioclase, hornblende, andquartz. No biotite grains are identified. Euhedral titanite occurs sporadically within the groundmass. Quartz is subhedral to anhedral in shape with serrated boundaries. Michel-Levy tests for plagioclase yields oligoclase compositions (An17) for primary grains, and more andesine compositions (An30) for albite rims near the margins for feldspar grains. The rock is weakly deuterically altered and magmatic grains experience relatively no internal strain. Alteration is relatively minor, and comprises seritization of plagioclase, very weak chloritization of hornblende, and calcite which commonly occurs in the interstices of quarts and plagioclase clasts. Structural Relationships:The rock is relatively undeformed. Grains are randomly oriented, but may be interpreted as having a very weak magmatic foliation. This magmatic foliation is dominantly defined by plagioclase grains. Embayed boundaries in quartz grains are uncommon, but when observed, indicate relatively minor bulging recrystallization. Weakly chloritized hornblende is typically undeformed. Very few grains show internal strain that weakly destruct cleavage of each mineral. Location: Sample was collected from drill hole 2007-098 at 44.83 metres down hole in deuterically alterered Feldspathic Mine Pase tonalite.    Minerals Modal (%) Size (mm) Quartz 30 2-4Plagioclase 35-45 2-4Sericite 10-15 <0.001Hornblende 5-8 2-5Titanite 3-4 <0.1Chlorite 2-3 2-5Ankerite 1 <0.015 mmPPL XPL225Structural Relationships:The quartz- and mica-rich bands form shear bands that are dragged by R and Y shears. Reidel shears drag muscovite shear bands and rotate quartz porphyroclasts that define a dextral strike-slip shear sense. Molybdenite forms a parasitic fold by rotation into the fault fabric. Quartz porphyroclasts contain weak to moderate bulging recrystallization. Opaques are slightly elongate, and are suspected to be relic pyrite are brittly fractured.   YXSample: NM-13-002Textural Description:Quartz- and mica-rich bands comprise the shear fabric. Quartz-rich bands are composed of sigmoidal quartz porphyroclasts and lenticular quartz boudins rotated into the fabric. Quartz boudins may have initially been hydrothermal veins or veinlets. Muscovite-rich bands comprise muscovite shear bands, molybdenite, and chlorite (after hornblende). Molybdenite occurs as thin, fragmented sheets that are rotated into the fabric. Muscovite grains are large in size. Vuggy texture produced from weathering of minerals commonly contains limonite concentrated along the rim of the vugs. Sulphides are opaques that are difficult to distinguish under reflected light as they have been oxidized to malachite and limonite. Location: Sample looks down at the strike-slip component of North Fault 8b (160/84), a N-S trending dextral oblique-slip fault with east side-down.Minerals Modal (%) Size (mm) Sericite 25-35 0.1Primary Quartz 30-40 2-4Secondary Quartz 30-40 <0.01Chlorite 3-5 0.1Limonite 6-8 0.1Malachite 1 0.01Molybdenite trace <0.0015 mmPPL XPL226Structural Relationships:Quartz boudins contain a weak subgrain rotation (SGR) recrystallization that forms a lattice preferred orientation. The strong fault fabric is defined by muscovite that is strongly crenulated and forms a weakly defined S2 crenulation cleavage. However, shear sense is indeterminate which suggests the dip-slip component is minimal despite shear sense indi