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Sinsistral high strain in the Coast Mountains near Bella Coola, West Central British Columbia Demerse, Deirdre K. 2008

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SINISTRAL HIGH STRAIN IN THE COAST MOUNTAINS NEAR BELLA COOLA, WEST CENTRAL BRITISH COLUMBIA by DEIRDRE K. DEMERSE B.Sc. (Hons.), University of British Columbia, 2005  A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE STUDIES (Geological Sciences)  THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver)  April, 2008 © Deirdre K. Demerse, 2008  ABSTRACT  The Bella Coola area geographically straddles two zones of known Early to midCretaceous sinistral ductile strain; the Grenville, Kitkatla, and Principe-Laredo shear zones to the northwest located near Prince Rupert, B.C., and the Tchaikazan fault system to the southeast. At the latitude of Bella Coola in west-central B.C., the Pootlass High Strain Zone (PHSZ) is a ductile, subvertical, shear zone system at least 2 km wide and at least 30 km long. The purpose of this study is to determine the age, kinematics, and tectonic significance of the PHSZ, and to investigate whether or not it was active as a kinematic link to Early to mid-Cretaceous sinistral ductile strain zones in the western Canadian Cordillera. This thesis reports recent observations from field mapping and new geochronological, microstructural, and petrological data, from which the PHSZ is characterized and placed into a regional tectonic framework. U-Pb and 'Ar/"Ar isotopic geochronology indicate that regionally extensive, southwest-vergent folding in the PHSZ area was active prior to 114 Ma and persisted until at least 73 Ma. High-temperature, ductile, sinistral non-coaxial strain in the PHSZ was accommodated between 76 (or earlier) and 62 Ma. Localization of high strain is associated with the emplacement of plutonic rock and abundant intrusive sills, which likely acted as a strain-softening mechanism. L-tectonites within the deformed plutonic rocks attest to the weakness of the rocks during deformation and support syn-kinematic magmatism. Geothermometric and petrological data suggest that deformation occurred at temperatures of 537 to 731°C and at crustal depths of —23 km. The PHSZ is interpreted to be kinematically related to the Talchako Fault to the east, which was active as a sinistral mylonitic shear zone between 70 and 65 Ma. A  ii  kinematic relationship between the PHSZ and the Grenville, Kitkatla and PrincipeLaredo shear zones near Prince Rupert imply a protracted history of sinistral transpression in the Coast Mountains of British Columbia that persisted in the Bella Coola region through Late Cretaceous time.  iii  TABLE OF CONTENTS  ABSTRACT  ^ii  TABLE OF CONTENTS ^  iv  LIST OF TABLES  ^ix  LIST OF FIGURES  ^x  PREFACE  ^xii  ACKNOWLEDGEMENTS ^  xiii  CHAPTER ONE  1.0 INTRODUCTION  ^1  1.1 STATEMENT OF PROBLEM ^ 1.2 GEOLOGICAL SETTING  2 ^2  1.2.1 Tectonic Setting  ^2  1.2.2 The Amalgamation of the Insular and Intermontane Superterranes 1.2.3 Regional Geology  ^4 ^7  1.2.3.1 Supracrustal Rocks of the Stikine Terrane  ^8  1.2.3.2 Igneous Rocks of the Coast Plutonic Complex  ^9  1.2.3.3 Regional Structural Features  ^  10  iv  CHAPTER TWO  2.0 INTRODUCTION  ^17  2.1 GEOLOGICAL SETTING OF THE PHSZ  ^19  2.1.1 Lithology  ^19  2.1.2 Structural Geology  ^19  2.2 THE POOTLASS HIGH STRAIN ZONE SYSTEM  ^21  2.2.1 Introduction  ^21  2.2.2 Snootli Peak — "Background" Style of Deformation  ^22  2.2.2.1 Lithology  ^22  2.2.2.2 Structural Geology  ^23  2.2.2.3 Petrology  ^25  2.2.2.4 Deformation Microstructures  ^25  2.2.3 Mount Pootlass — The Type Locality for PHSZ Style of Deformation ... ^26 2.2.3.1 Lithology  ^26  2.2.3.2 Structural Geology  ^28  2.2.3.3 Petrology  ^30  2.2.3.4 Deformation Microstructures 2.2.3.5 Interpretation 2.2.4 Falls Camp Locality  ^31 ^  33  ^36  2.2.4.1 Lithology  ^36  2.2.4.2 Structural Geology  ^37  2.2.4.3 Petrology  ^38  2.2.4.4 Deformation Microstructures  ^39  2.2.4.5 Interpretation  ^  2.2.5 Jump Across Locality  40 ^41  2.2.5.1 Lithology  ^41  2.2.5.2 Structural Geology  ^42  2.2.5.3 Petrology  ^43  2.2.5.4 Deformation Microstructures  ^43  2.2.6 Horseshoe Hill Locality ^  .....^44  2.2.6.1 Lithology  ^44  2.2.6.2 Structural Geology  ^45  2.2.6.3 Petrology  ^46  2.2.6.4 Deformation Microstructures  ^46  2.2.7 Mount Cloud Locality  ^47  2.2.7.1 Lithology  ^47  2.2.7.2 Structural Geology  ^48  2.2.7.3 Petrology  ^48  2.2.7.4 Deformation Microstructures 2.2.8 The PHSZ: Summary of Observations 2.3 GEOTHERMOMETRY ^ 2.3.1 Introduction to Garnet and Biotite Geothermometry  ^49 ^50 52 ^52  2.3.2 Garnet and Biotite Geothermometry Results and Interpretations  ^53  2.3.3 Introduction to Amphibole and Plagioclase Geothermometry  ^54  2.3.4 Amphibole and Plagioclase Geothermometry Results and Interpretations... ^55 2.4 GEOCHRONOLOGY ^  57 vi  ^57  2.4.1 U-Pb Isotopic Dating  ^58  2.4.2 40Ar/39Ar Isotopic Dating 2.4.2.1 Age Constraints for Coaxial Strain  ^58  2.4.2.2 Age Constraints for Non-Coaxial Strain  ^59  2.4.2.3 Interpretation of 40Ar/39Ar Cooling Ages  ^60  ^  61  2.5 DISCUSSION  2.5.1 Variation Along Strike  ^  2.5.2 The Significance of Syn-Kinematic Melt in the PHSZ  ^63 ^64  2.5.3 Crustal Delamination  ^67  2.5.4 Deformation Models for the PHSZ  ^67  2.5.4.1 Sinistral Transpression  ^68  2.5.4.2 Flattening Induced Conjugate Shear Zones  ^69  2.5.4.3 Sinistral Extensional Step-Overs 2.5.5 Summary of Conclusions  61  ^71  CHAPTER THREE ^3.0 SUGGESTIONS FOR FUTURE WORK 3.0.1 Constraints on the Geometry of the PHSZ 3.0.2 Constraints on Pressure and Temperature of Deformation 3.0.3 Constraints on Kinematics 3.0.4 Constraints on Tectonic Significance REFERENCES^  113 ^113  ^114 ^114 ^115 116  vi i  APPENDICES  Appendix I Petrographical Descriptions and Microphotographs  ^123  Appendix II Garnet/Biotite and Amphibole/Plagioclase Geothermometry:^124 Methodology and Data ^ ^179 Appendix III U-Pb and 40Ar/ 39Ar Geochronology: Methodology and Data  vi i i  LIST OF TABLES  Table II-A Geothermometry Sample Locations and Descriptions  ^127  Table II-B Garnet/Biotite Microprobe Data  ^128  Table II-C Garnet/Biotite Calculations ^  145  Table II-D Amphibole/Plagioclase Microprobe Data  ^147  Table II-E Amphibole/Plagioclase Calculations  ^176  Table III-A Geochronology Sample Locations and Descriptions Table III-B U-Pb LA-ICPMS Data ^ Table III-C 40Ar/39Ar Data ^  ^183 184 186  ix  LIST OF FIGURES  Figure 1.1 Location of the PHSZ and Other Major Structures in the Western^14 Canadian Cordillera ^ Figure 1.2 Regional Geology of Bella Coola  ^15  Figure 2.1 Geological Setting of the PHSZ with Fly Camp Locations  ^72  Figure 2.2 Snootli Peak Geology and Schematic Cross Section Figure 2.3 Snootli Peak Stereonet Diagrams Figure 2.4 Snootli Peak Field Photographs  ^74 ^76 ^77  Figure 2.5 Microphotographs of Rocks from Snootli Peak  ^78  Figure 2.6 Mount Pootlass Geology and Schematic Cross Section  ^79  Figure 2.7 Mount Pootlass Field Photographs ^  80  Figure 2.8 Field Photographs of Syn-Kinematic Melt at Mount Pootlass  ^81  Figure 2.9 Mount Pootlass Stereonet Diagrams ^  82  Figure 2.10 Field Photographs of Kinematic Indicators at Mount Pootlass  ^83  Figure 2.11 Microphotographs of Rocks from Mount Pootlass: Metamorphism..... ^84 Figure 2.12 Microphotographs of Rocks from Mount Pootlass: Coaxial Strain ^ 85 Figure 2.13 Microphotographs of Rocks from Mount Pootlass: Non-Coaxial ^86 Strain ^ Figure 2.14 Falls Camp Geology  ^87  Figure 2.15 Falls Camp Field Photographs  ^88  Figure 2.16 Falls Camp Stereonet Diagrams  ^89  Figure 2.17 Microphotographs of Rocks from Falls Camp  ^90  Figure 2.18 Microphotographs of Rocks from Falls Camp: Deformation ^91 Microstructures in Quartz ^ Figure 2.19 Jump Across Geology ^  92 x  Figure 2.20 Jump Across Field Photographs Figure 2.21 Jump Across Stereonet Diagrams ^  ^93 94  Figure 2.22 Microphotographs of Rocks from Jump Across ^ 95 Figure 2.23 Horseshoe Hill Geology and Schematic Cross Section  ^96  Figure 2.24 Horseshoe Hill Stereonet Diagrams ^  97  Figure 2.25 Horseshoe Hill Field Photographs ^  98  Figure 2.26 Microphotographs of Rocks from Horseshoe Hill Figure 2.27 Mount Cloud Geology ^  ^99 100  Figure 2.28 Mount Cloud Field Photographs  ^101  Figure 2.29 Mount Cloud Stereonet Diagram  ^102  Figure 2.30 Microphotographs of Rocks from Mount Cloud  ^103  Figure 2.31 Microphotographs of Samples Analyzed with Garnet/Biotite Geothermometry  ^104  Figure 2.32 Microphotographs of Samples Analyzed with Amphibole/Plagioclase ^105 Geothermometry ^ Figure 2.33 Concordia Diagram and Weighted Averages Chart  ^106  Figure 2.34 40Ar/ 39 Ar Step Heating Diagrams and Cooling Ages  ^107  Figure 2.35 Strain Partitioning as a Result of Oblique Convergence  ^108  Figure 2.36 Schematic Representation of Late Cretaceous Sinistral Transpression ^110 in the Bella Coola Area ^ Figure 2.37 Hypothetical Conjugate System of Shear Zones in the PHSZ  ^111  Figure 2.38 The PHSZ and Talchako Fault as a System of Sinistral Extensional ^112 Step-Overs ^  xi  PREFACE  This thesis is organized in three chapters. Chapter 1 is an introduction to the thesis question and a review of the geology of the Bella Coola area. Previous work conducted in the study area is also reported. Chapter 2 presents the regional lithologies and structural geology of the Bella Coola area. Field and microstructural data, observations and results from the PHSZ are presented, followed by a discussion and summary of conclusions of the thesis. Chapter 2 will later be reformatted for publishing. Chapter 3 provides suggestions for future study. Appendices report data for geochronological and geothermometric studies. Petrographical descriptions with accompanying microphotographs are available as metadata on an accompanying CD.  xii  ACKNOWLEDGEMENTS  This research has been funded by an NSERC Discovery grant to Dr. L.A. Kennedy and an NSERC-PGSM scholarship to the author. Additional support was provided by the Batholiths project. Thanks to Dr. L.A. Kennedy for her ambitious spirit and guidance through the twists and turns of the PHSZ. Many thanks to Mr. Tom Ulrich and Dr. Jim Mortensen of the University of British Columbia for much needed age dates. Special thanks to Julie Hamblock of the University of Texas at El Paso for her timely assistance in the depths of P/T calculations. A huge thanks is extended to my family for their unwavering support throughout my post-secondary education. I am forever grateful to Joseph Hopkins for endless encouragement and for sticking it out through blasting winds, snow, sleet, and endless hours of rain for a few good days of blissful sunshine in the Coast Mountains. Finally, a warm thanks is extended to the wonderful people of the Bella Coola Valley for welcoming us into their community.  CHAPTER ONE  1.0 INTRODUCTION Sinistral displacement along the suture zone between and within the Intermontane and Insular superterranes is thought to have played a significant role in their amalgamation during the Early to mid-Cretaceous. Monger et al. (1994) propose that up to 800 km of orogen-parallel, left-lateral motion was accommodated during this time. Early to mid-Cretaceous sinistral translation in the western Canadian Cordillera is recorded by several major shear zones in northwestern and southwestern British Columbia. The Grenville, Kitkatla, and Principe-Laredo sinistral shear zones, located near Prince Rupert, B.C., northwest of Bella Coola, were active between 110 and 87 Ma during voluminous batholith intrusion (Chardon et al., 1999) (Figure 1.1). Sinistral movement along these shear zones was coeval with the formation of thrust belts flanking the Coast Plutonic Complex, suggesting that transpression was a first order process during the construction of the Coast Mountains orogen in the mid-Cretaceous (Chardon et al., 1999). To the southeast of Bella Coola, the Tchaikazan River area contains several sinistral brittle and ductile fault zones, with a latest movement dated at 89 ± 0.9 Ma (Israel et al., 2006) (Figure 1.1). At the latitude of Bella Coola in west-central B.C., the Pootlass High Strain Zone (PHSZ) (Figure 1.1) is a major corridor of high-temperature deformation that may provide evidence for sinistral strain accommodation in the westcentral Canadian Cordillera, providing a kinematic link between known sinistral shear zones in the northwest and the Tchaikazan system to the southeast.  1  1.1 STATEMENT OF PROBLEM The Pootlass High Strain Zone (PHSZ), located near Bella Coola, B.C. (Figure 1.1), was first recognized by Mahoney et al. (2002) and was referred to as the Jump Across Shear Zone. Mahoney et al. (2002) report high-angle ductile shear zones, varying in width from a few metres to over a kilometer, with locally abundant protomylonite and mylonite and unclear kinematic sense. The Bella Coola area geographically straddles two zones of known Early to mid-Cretaceous sinistral ductile strain; the Grenville, Kitkatla, and Principe-Laredo shear zones to the northwest (Figure 1.1), located near Prince Rupert, B.C., and the Tchaikazan fault system to the southeast (Figure 1.1). The purpose of this study is to determine the age, kinematics and tectonic significance of the PHSZ, and investigate whether or not it was active as a kinematic link to Early to midCretaceous sinistral ductile strain zones in the western Canadian Cordillera.  1.2 GEOLOGICAL SETTING 1.2.1 Tectonic Setting The PHSZ is a ductile shear zone system, at least 2 km wide and at least 30 km long, located in the Coast Belt just northeast of the boundary between the Intermontane and Insular superterranes, which is demarked by the Coast Shear Zone at this latitude (Figure 1.1). The Insular superterrane is composed of the Alexander and Wrangell (Wrangellia) terranes. The Alexander terrane includes low to medium grade Late Proterozoic to Triassic metavolcanic, metasedimentary and metaigneous rocks, whereas Wrangellia is composed of Middle to Late Triassic flood basalts and carbonates underlain by Late  2  Paleozoic sedimentary and arc sequences (Gehrels and Boghossian, 2000). The Alexander and Wrangell terranes are interpreted to have been consolidated by Carboniferous time, and subsequently accreted as a single crustal block (the Insular superterrane) to the western edge of the Intermontane superterrane by mid-Jurassic time (Monger and Journeay, 1994; Dickinson, 2004). At the latitude of Bella Coola, only the Alexander terrane is exposed. In the Bella Coola area, the Intermontane superterrane is represented by sedimentary and volcanic rocks of the Stikine terrane belonging to the Early to Middle Jurassic Hazelton Group. In the Bella Coola area, the Hazelton Group is dominated by massive olive-grey to dark grey andesite and basaltic andesite flows and associated fragmental rocks interleaved with locally significant rhyolite (Mahoney et al., 2002). The aerially extensive Hazelton Group likely represents coalescing deposits from one or more volcanic centers (Diakow et al., 2002). The Hazelton Group is unconformably overlain by the Early to mid-Cretaceous Monarch assemblage (Haggart et al., 2003), which consists of a thick succession of olive-green, dacitic to andesitic flows, associated breccias, volcaniclastic sandstone, tuff, and slate (Struik et al., 2002). The Coast Plutonic Complex (Figure 1.1) is a magmatic and metamorphic belt that extends more than 1800 km from Alaska to southernmost B.C. and northwest Washington (Rusmore et al. 2001). Plutonic rocks of the Coast Plutonic Complex vary in age from earliest Jurassic to Eocene and thus record over 150 My of magmatism and deformation in the western Canadian Cordillera. The formation of this voluminous plutonic belt is attributed to the tectonic interaction of the Insular and Intermontane  3  superterranes and represents a long-lived arc intruded along their suture zone (van der Heyden, 1992). The Coast Plutonic Complex is cut by the Coast shear zone (Figure 1.1), a major transpressional structure that extends —1200 km from Skagway, Alaska, to Machmell River, B.C. (Rusmore et al., 2001). The Coast shear zone is interpreted to have accommodated significant dextral translation between 85 and 65 Ma (Hollister and Andronicos, 1997; Andronicos et al., 1999). The amount of dextral offset accommodated along the Coast shear zone in the Late Cretaceous is undefined. Wyld et al. (2006) speculate large (-125 km) movement along the Coast shear zone based on the width of the shear zone (10-15 km wide), and its role as a deep-seated, subvertical boundary that juxtaposes mid-Cretaceous metamorphic rocks to the west against predominantly Paleogene Coast plutonic rocks to the east. At the Bella Coola latitude, movement along the Coast shear zone predominantly consisted of northeast-vergent thrusting in the latest Cretaceous (Rusmore et al., 2001).  1.2.2 The Amalgamation of the Insular and Intermontane Superterranes The timing of accretion of the Insular superterrane (Figure 1.1) to the outboard margin of the Intermontane superterrane (Figure 1.1) remains a topic of debate. Initial collision between the two superterranes is thought to have occurred by mid-Jurassic time, or possibly as early as the latest Triassic, and reconfiguration may have continued into the Tertiary (van der Heyden, 1992; Gehrels, 2001). Convergence of the superterranes was followed by east-west extension, which is thought to have been an important contributor to arc and intra-arc basin development (Mahoney et al., 2002). Basin  4  collapse, and the development of a mid- to Late-Cretaceous southwest-verging fold and thrust system along the western margin of the Coast Plutonic Complex, termed the Coast Belt thrust system, records the final accretion of the Insular and Intermontane superterranes (Journeay and Friedman, 1993; Rusmore and Woodsworth, 1994). A system of northeast to north verging fold and thrusts developed in the Late Cretaceous along the eastern margin of the Coast Plutonic Complex. This system is termed the Late Cretaceous eastern Waddington thrust belt, and is interpreted as a backthrust system to the more extensive southwest-verging system (Rusmore and Woodsworth, 1994). Up to 800 km of relative left-lateral motion between the Intermontane and Insular superterranes may have occurred during the late Early Cretaceous (Monger et al., 1994). Monger et al. (1994) propose that during amalgamation, a portion of the arc and accretionary complex was transected acutely and sinistrally translated along an orogenparallel fault system. Subsequent imbrication of the sinistrally displaced portion of the accretionary complex beneath the remaining Coast Belt to the east resulted in the northward pinching of an intervening ocean basin (the Bridge River ocean) and the doubling of the Coast belt forearc (now the Okanagan-Spences Bridge and Gambier arcs) (Monger et al., 1994). This model explains the presence of intra-arc basins flanking the Coast Belt north of lat 54°N, and similarly placed inter-arc basins south of lat 54°N with oceanic basements (Monger et al., 1994). Early to mid-Cretaceous sinistral translation is recorded by the Grenville, Kitkatla, and Principe-Laredo shear zones near Prince Rupert, B.C. (Chardon et al., 1999). These shear zones exhibit steep to vertical gneissic foliation in plutonic rock and intense isoclinal folding in supracrustal rocks of lower greenschist to amphibolite  5  metamorphic grade, with estimated temperatures of deformation between 300 and 500°C (Chardon et al., 1999). Due to its geometry, the Skeena Fold Belt, northeast of Prince Rupert, is interpreted to have formed during sinistral oblique convergence in Early to mid-Cretaceous time (Evenchick, 1997, Evenchick, 2001). Thin-skinned folds of two dominant orientations characterize the Skeena Fold Belt; northwest-trending folds occupy the central and eastern parts, whereas northeast-trending folds occur locally along the west side of the belt (Evenchick, 2001). Folds are upright to overturned, and have wavelengths of several hundred metres to more than a kilometer (Evenchick, 2001). The Tchaikazan fault, in southwestern B.C., is the locus of a regionally extensive system of sinistral translation, ending by 89 ± 0.9 Ma (Israel et al., 2006) (Figure 1.1). Fault zones in the Tchaikazan fault system are steeply dipping and discontinuous, with the exception of the Tchaikazan fault that has a strike length of several kilometers (Israel et al., 2006). Fault thicknesses range from several metres to hundreds of metres (Israel et al., 2006). A well-developed foliation, defined by illite, chlorite, and calcite mineral growths, and rare mineral lineations defined by elongated quartz, occur in brittle-ductile fault zones of the Tchaikazan fault system, with low-grade interpreted metamorphic conditions (Israel et al., 2006). Compressional structures, indicating southwest-directed contraction, are also reported coeval with sinistral shearing throughout the Coast Plutonic Complex and are suggestive of a sinistral transpressive regime (Journeay and Friedman, 1993; Rusmore and Woodsworth, 1994; Schiarizza et al., 1997). Dextral transpression began in the Late Cretaceous (-70 Ma), and continued into the Tertiary (Andronicos et al., 1999). During this phase of deformation, compressional strain appears to have been accommodated along the Coast shear zone (Figure 1.1), while  6  dextral translation occurred predominantly along the Yalakom fault system in southwestern B.C. (Umhoefer and Schiarizza, 1996; Andronicos et al., 1999; Rusmore et al., 2001) (Figure 1.1). Dextral transtension, resulting from a relative change in plate motions at —59 Ma (Engebretson et al., 1985; Andronicos et al., 2003; Rusmore et al., 2005), brought on widespread dextral brittle faulting throughout the western Canadian Cordillera from the latest Cretaceous until Eocene time (Umhoefer and Schiarizza, 1996; Schiarizza et al., 1997).  1.2.3 Regional Geology Baer (1973) first mapped the Bella Coola area at a scale of 1:250,000 during the 1962-1965 field seasons. Preliminary U-Pb ages and field observations were reported by van der Heyden (1991). More recently, Rusmore et al. (2000, 2001), and Gehrels and Boghossian (2000) conducted detailed mapping of the Coast shear zone and other major structures in the Bella Coola area. In 2001, a Targeted GeoScience Initiative was commissioned by the Geological Survey of Canada and the British Columbia Geological Survey to map the Bella Coola map sheet (NTS93D). Results from this project are reported in Mahoney et al. (2002), Struik et al. (2002), Diakow et al. (2002), Hrudey et al. (2002), Israel and Kennedy (2002), Sparks and Struik (2002), and Struik and Velijkovic (2001). Recent U-Pb ages are reported by van der Heyden (2004). A compilation of geological mapping conducted by the Target GeoScience Initiative is summarized in Haggart et al. (2003). The latest version of the Bella Coola map sheet is provided by Haggart et al. (2006).  7  1.2.3.1 Supracrustal Rocks of the Stikine Terrane Supracrustal rocks are widely distributed across the Bella Coola area and consist of magmatic-arc volcanic and sedimentary strata of the Early to Middle Jurassic Hazelton Group, and the Early to mid-Cretaceous Monarch assemblage (Figure 1.2). Lower Hazelton Group strata exposed in the Bella Coola area (Figure 1.2) consists of maroon and green massively bedded basalt and basaltic andesite flows interlayered with crudely stratified fragmental rocks and minor slate (Struik et al., 2002; Haggart et al., 2003). In places the flows are coarsely plagioclase-phyric or amygdaloidal (Struik et al., 2002). Fragmental rocks include tuff and tuff breccia, ranging in composition from dacite to quartz-phyric rhyolite (Haggart et al., 2003). Interbedded rhyolitic tuffs display a distinctive light weathering colour (Haggart et al., 2003). A thick sedimentary succession, consisting of coarse-grained volcanic lithic arenite, arkosic sandstone, and conglomerate overlies the Lower mafic to intermediate volcanic sequence (Haggart et al., 2003). Sedimentary structures observed within the lithic arenite include: crude parallel laminae, graded bedding, and rare trough cross-stratification (Haggart et al., 2003). The Hazelton Group is unconformably overlain by the Early to midCretaceous Monarch assemblage (van der Heyden et al., 1994; Haggart et al., 2003). In places, the contact between the Hazelton Group and the Monarch assemblage is sheared or faulted (Haggart et al., 2003). The Monarch assemblage (Figure 1.2) is a thick succession of olive-green amygdaloidal basaltic andesite and basalt with rare columnar jointing, forming massive step-like cliffs (Haggart et al., 2006; Haggart et al., 2003, Mahoney et al., 2002). Flows are associated with andesitic breccia and tuff breccia (Haggart et al., 2006). Intercalated  8  rusty argillite, laminated siltstone, feldspathic sandstone, and minor granule-pebble conglomerate form locally continuous stratigraphic sequences up to 2.5 km thick (Struik et al., 2002; Mahoney et al., 2002). Stratigraphy within the Monarch assemblage is complex as a result of abrupt lateral facies changes and structural deformation (Haggart et al., 2003). The base of the Monarch assemblage overlies a quartz diorite pluton that yields a 134 ± 0.3 Ma U-Pb zircon age (van der Heyden, 1991). Regionally, the Monarch assemblage is interpreted to be Valaginian in age, partially on the basis of sparse ammonite fauna noted by Struik et al. (2002).  1.2.3.2 Igneous Rocks of the Coast Plutonic Complex Plutonic rocks exposed in the Bella Coola area are interpreted to be Jurassic to Eocene in age, and are subdivided into several plutonic suites and one undifferentiated plutonic complex (Figure 1.2). The following brief descriptions are taken mostly from Haggart et al. (2006). The Four Mile plutonic suite (U-Pb ca. 67-73 Ma)(Figure 1.2) is a coarse-grained, equigranular muscovite-biotite-bearing granite (Hrudey et al., 2002). The presence of two micas indicates that the granite is likely an S-type granite derived from partial melting of crustal sources (Winter, 1998). Garnet, pink potassium feldspar megacrysts, and aplite dykes with pegmatitic segregations bearing garnet and muscovite occur locally. The Four Mile plutonic suite is unfoliated, except possibly at its margins, and forms prominent exposures characterized by curvi-planar exfoliation joints. The Four Mile plutonic suite reportedly truncates northwest-trending folds and shear zones in the Bella Coola area (Hrudey et al., 2002).  9  The Fougner plutonic suite (U-Pb ca. 67-68 Ma) (Figure 1.2) is a medium-to coarse-grained, equigranular to locally inequigranular diorite to granodiorite with hornblende, biotite and conspicuous sphene. Locally, this plutonic suite includes potassium feldspar megacrysts and a distinct salt-and-pepper fresh appearance. The Big Snow plutonic suite (U-Pb ca. 79-95 Ma) (Figure 1.2) comprises equigranular, coarse-grained biotite-monzogranite and biotite-hornblende tonalite to granodiorite. The Desire plutonic suite (U-Pb ca. 118-124 Ma) (Figure 1.2) comprises equigranular, fine- to medium-grained hornblende diorite to quartz diorite, and mediumto coarse-grained biotite-hornblende tonalite. The Desire plutonic suite contains abundant screens and xenoliths of metavolcanic rock and amphibolite (Haggart et al., 2006). This plutonic suite displays both magmatic and tectonic foliations. On Mount Pootlass, the Desire plutonic suite is intruded by an abundance of felsic and mafic sills that occur parallel to the dominant shear fabric. Near the Dean Channel, exposures of plutonic rock consist of undifferentiated granodiorite, diorite, and hornblende-biotite tonalite that are interpreted to be Jurassic to Cretaceous in age and have not been assigned to a plutonic suite.  1.2.3.3 Regional Structural Features Rocks in the Bella Coola area were formed during the uplift and subsidence of an arc constructed by the long-lived interaction of the Insular and Intermontane superterranes. Convergence of the superterranes in the Jurassic was followed by eastwest extension, and the intra-arc basinal emplacement of the Early to Middle Jurassic  10  Hazelton Group (Mahoney et al., 2002) (Figure 1.2). East-west crustal extension (locally greater than 40%) and uplift in the Early to mid-Cretaceous generated the Monarch assemblage (Struik et al., 2002) (Figure 1.2), and coincided with the emplacement of the Desire plutonic suite. Horizontal shortening in the mid-Cretaceous is recorded by upright, tight to isoclinal, southwest-verging folds in the western portion of the Bella Coola area. These folds are interpreted to be a part of a regionally extensive, southwest-verging thrust belt flanking the western margin of the Coast Plutonic Complex that was active from 100 to 91 Ma (Journeay and Friedman, 1993; Rusmore and Woodsworth, 1994). Northeast-verging folds and thrusts record Late Cretaceous crustal contraction in the Bella Coola area. The eastern portion of the Bella Coola area exhibits a welldeveloped system of northwest-trending, northeast-verging folds and thrust faults (Mahoney et al., 2002). The folds vary in their geometry from close to isoclinal and occur at the outcrop and map scale. The Sheemahant shear zone, located approximately 40 km south-southeast of Bella Coola (Figure 1.1), is a major northeast-verging thrust interpreted to have been active between 91 and 54 Ma (Rusmore et al., 2000). The shear zone strikes northwest (-300°), dips —55° to the southwest, and exhibits tonalitic protomylonites and mylonites. Northeast-verging folds and thrusts in the Bella Coola area are interpreted to be kinematically linked to the Late Cretaceous eastern Waddington thrust belt exposed near Mount Waddington in southwestern B.C. (Rusmore and Woodsworth, 1994; Rusmore et al., 2001). Sinistral transpression in the Late Cretaceous was accommodated in part by the Talchako fault, located 45 km east of Bella Coola (Figure 1.2). The Talchako Fault is a  11  steep, northwest-trending mylonitic ductile shear zone that is interpreted to have accommodated at least 45 km of sinistral offset between 70 Ma (or earlier) and 65 Ma (S. Israel, pers. comm. 2008). Sinistral transpression may also have been accommodated along the northwest-striking Kimsquit fault that follows the east edge of the Dean Channel, roughly 45 km north-northwest of Bella Coola (Figure 1.2). The Kimsquit fault reportedly exhibits sinistral brittle-ductile kinematic indicators (M.E. Rusmore, pers. comm. 2007); however, ages of movement are currently unpublished. A series of northwest-trending subvertical shear zones exposed between Bella Coola and the Dean Channel were first recognized by Mahoney et al. (2002) as the "Jump Across Shear Zone", and are now termed the Pootlass High Strain Zone (PHSZ) (Figure 1.2). Mahoney et al. (2002) report high-angle ductile shear zones, varying in width from a few metres to over a kilometer, with locally abundant protomylonite and mylonite. Shear fabric is delineated by stretched mafic enclaves, fractured, elongate to rotated, plagioclase porphyroclasts and a well-developed foliation (Mahoney et al., 2002). Mineral lineations are locally well-developed, and are defined by elongate quartz rods and streaked biotite (Mahoney et al., 2002). Shear fabric is gradational along shear-zone margins with undeformed protolith (Mahoney et al., 2002). Syn-kinematic magmatism is indicated by deformed rhyolitic and metabasaltic dykes (Mahoney et al., 2002). Preliminary structural interpretations made by Mahoney et al. (2002) report a multi-stage deformational history of complex transpressional flow. Compression in the Bella Coola area continued along the Coast shear zone through the Paleocene. At the latitude of Bella Coola, the Coast shear zone strikes roughly northwest and is located approximately 20 km southwest of Bella Coola (Figure  12  1.2). Reverse movement (northeast side up) on the Coast shear zone between ca. 65 and 55 Ma is reported by Rusmore et al. (2001). North- to northwest-trending brittle dextral faults that cut all rock types are common in the Bella Coola area, and are interpreted to be a part of widespread rightlateral brittle faulting throughout the western Canadian Cordillera brought on by dextral transtension from latest Cretaceous to Eocene time (Umhoefer and Schiarizza, 1996; Schiarizza et al., 1997). Orogen-wide extension, marked by the exhumation of mid-crustal arc rocks within the Coast Mountains, occurred between 70 and 52 Ma (Rusmore et al., 2005). Exhumation ages are based on metamorphic pressure and temperature data obtained from the Central Gneiss Complex along the Douglas Channel (Figure 1.1), approximately 140 km northwest of Bella Coola (Rusmore et al., 2005).  13  ^ ^  a) C O^a) N^c .._, c^  ( ).  0  N c ,c2 • ^iTs co 7. C (Ks a) a)^_c C c -c 4- w o 0 c . a) N M i 2.—. CT3 -.'' E it I_ -E^D ■4— C 6:3  -o  ,  cl, a) (13^u) C.) C ,.,_ 03 _C 4-^ 03 03 _1 CD 0 N E E ÷..^-.^CO 0- > 0 CD 0 0  a. 0 a.  —I '  — as C o _c • -^a) <-) 4=.^ri c) ai (6L C cKs 2 ^_c ^ 'E _Y 0-1 ^, CD 0 ,( 13 •-• , c).. :.=• ,--• N 1-- I— ,,IY ' U) . . . N 0 1 0 N Li- (1) H H >- cn  0 • fn 2  w w  6  ■  0 N1.6  I  000'0E17 ^  E  O Co  14  ^ ^ ^  E  i  0)  "-  c  CO^ 0^ 0^ C \ I 0.-i^03  ru  . .^ co - E .N-^o -0  0  T  ID C \I ,D  -a  2 ° 0 o (t  0 0_ cr--N- N L.= tco as^  -0 , co a  N.— o co ti a) 0 (1:5 a)^ 0^L C i: 0^  a) t._  ,_ cs)  co^ZD CC °  CO^a) ^En To^ 0.. -0^ CO^:73 ,^as co i—^w o co0) -0^  ^c5  0^°,  E O CN  o  3  ,  ays)  ^000`00L ^  ../. "....„.  \.N\'‘-`--!  _,,  ,,,/,  -caw' ,-'"^/^co  gY^  -----  N-  O Lo co  15  LEGEND PALEOGENE Egm^Post-tectonic plutons (U/Pb 52-56 Ma, 52-53 Ma) Undifferentiated tonalite, quartz diorite, diorite, granitic orthogneiss LATE CRETACEOUS TO PALEOGENE LKFM Four Mile Plutonic Suite (U/Pb ca. 67-73 Ma) LATE CRETACEOUS LKF^Fougner Plutonic Suite (U/Pb ca. 67-68 Ma)  rim! LKBS Big Snow Plutonic Suite (U/Pb ca. 79-95 Ma) EARLY CRETACEOUS EKD^Desire Plutonic Suite (U/Pb ca. 118-124 Ma) ?VALANGINIAN, HAUTERIVIAN-BARREMIAN  7  IKMv Monarch Assemblage, volcanic rocks IKMs Monarch Assemblage, sedimentary rocks  SYMBOLS rrr  ti t ti  JURASSIC TO CRETACEOUS Undifferentiated granodiorite, JKP diorite, and hornblendebiotite tonalite JKF^Firvale Plutonic Suite (U/Pb ca. 131-140, 148-164 Ma)  fault possible shear zones mapped by Haggart et al., 2006 and Baer, 1973.  ?PLIENSBACHIAN TO TOARCIAN IJHv^Hazelton Group, volcanic rocks  ck.krA,.^outline of the 11-1-n_-n_^Pootlass High Strain Zone  IJHs^Hazelton Group, sedimentary rocks EARLY JURASSIC EJHL Howe Lake Plutonic Suite (U/Pb ca. 182-190 Ma) ?TRIASSIC TO ?LOWER JURASSIC rJv  permanent snowpack and glaciers  Undifferentiated basaltic and andesitic metavolcanic and  7  *  potential extensions of the Pootlass High Strain Zone  ^fly camp location  high strain zone  volcaniclastic rocks  Figure 1.2b. Bella Coola Geology Legend.  16  CHAPTER TWO  2.0 INTRODUCTION  Several major shear zones in northwestern and southwestern British Columbia record Early to mid-Cretaceous sinistral translation in the western Canadian Cordillera. The Grenville, Kitkatla, and Principe-Laredo sinistral shear zones, located near Prince Rupert, B.C. and to the northwest of Bella Coola, were active between 110 and 87 Ma during voluminous batholith intrusion (Chardon et al., 1999). To the southeast of Bella Coola, the Tchaikazan River area contains several sinistral brittle and ductile fault zones, with a latest movement dated at 89 ± 0.9 Ma (Israel et al., 2006). The Talchako fault, approximately 45 km east of Bella Coola (Figure 2.1), is a steep, northwest-trending corridor of deformation that was active as a mylonitic ductile shear zone, with sinistral movement between 70 Ma (or earlier) and 65 Ma (S. Israel, pers. comm. 2008). The Bella Coola area is characterized by predominantly lower greenschist facies arc-related metasedimentary and metavolcanic rocks that record horizontal shortening by both northeast- and southwest-verging fold and thrust systems (Haggart et al., 2003; Haggart et al., 2006). Within the Bella Coola area, the PHSZ is a system of northwesttrending shear zones exposed in anomalously high-grade rocks displaying ductile deformation of unknown age. The PHSZ was first recognized by Mahoney et al. (2002) and was referred to as the "Jump Across Shear Zone". Mahoney et al. (2002) report high-angle ductile shear zones, varying in width from a few metres to over a kilometer, with locally abundant protomylonite and mylonite and ambiguous kinematic sense. The PHSZ, located between the Dean Channel and Bella Coola, is at least 30 km in length,  17  but likely extends an additional 25 km towards Mount Saugstad in the southeast (Figure 2.1). With no clear tectonic connection between Early to mid-Cretaceous sinistral translation to the northwest (Grenville, Kitkatla, and Principe-Laredo shear zones) and to the southeast (Tchaikazan fault system), the PHSZ in the Bella Coola area stands out as a promising candidate to provide a kinematic link for sinistral translation through the western Canadian Cordillera. The purpose of this study is therefore to place constraints on the geometry, timing, kinematics and tectonic significance of the PHSZ. The following section will provide the results of detailed mapping, conducted at a scale of 1:10,000, at five fly camp locations within the PHSZ (Figure 2.1), along a strike length of roughly 30 km. In order to document the style of horizontal shortening that characterizes the Bella Coola area, and to use as a comparison for the fabrics found within the PHSZ, one additional fly camp was positioned outside of the PHSZ near to Snootli Peak (Figure 2.1). Observations from the Snootli Peak fly camp are used to provide a comparison to the remaining fly camp localities, which display evidence of non-coaxial strain. Results of microstructural analysis of oriented samples collected at the fly camps are presented, as well as results of geothermometric and geochronological studies.  18  2.1 GEOLOGICAL SETTING OF THE PHSZ 2.1.1 Lithology The Bella Coola area lies within the Intermontane superterrane just east of the Coast shear zone (Figure 2.1) which, at this latitude, marks the western margin of the Intermontane superterrane and the eastern margin of the Insular superterrane. The Bella Coola area is composed of arc-related volcanic and sedimentary rocks of the Early to Middle Jurassic Hazelton Group and the Early to mid-Cretaceous Monarch assemblage, as described in Chapter 1 (Figure 2.1). Obscuring these two crustal sequences is a diverse array of plutonic rocks ranging in age from Jurassic to Eocene, also described in Chapter 1 (Haggart et al., 2004) (Figure 2.1). The volume of plutonic rock intruding crustal units increases to the west (Haggart et al., 2003).  2.1.2 Structural Geology The western portion of the Bella Coola area is characterized by upright, tight to isoclinal, southwest-verging folds (Figure 2.1). Fold axes plunge shallowly to the northwest or southeast. Southwest-verging folds in the Bella Coola area are interpreted to be a part of a regionally extensive, southwest-verging thrust belt flanking the western margin of the Coast Plutonic Complex that was active from 100 to 91 Ma (Journeay and Friedman, 1993; Rusmore and Woodsworth, 1994). A well-developed system of northwest-trending, northeast-verging folds and some thrust faults occur in the eastern portion of the Bella Coola map sheet (Mahoney et. al., 2002) (Figure 2.1), and are interpreted as back thrusts to the more extensive southwest vergent system described above (Rusmore and Woodsworth, 1991). The folds vary in  19  their geometry from close to isoclinal and occur at the outcrop and map scale. Axial planar cleavages are well developed in slaty units. Mahoney et al. (2002) correlate this fold system to the Late Cretaceous, regional-scale, eastern Waddington thrust belt exposed near Mount Waddington in southwestern B.C. (Rusmore and Woodsworth, 1994). The eastern Waddington thrust belt is at least 40 km wide and 75 km long, and is comprised of a system of northwest striking and southwest dipping thrust faults that expose a range from low-grade rocks in the northeast to mid-amphibolite facies gneisses in the southwest (Rusmore and Woodsworth, 1994). The Sheemahant shear zone, located approximately 40 km south-southeast of Bella Coola, is a major northeast-verging thrust interpreted to have been active between 91 and 54 Ma (Rusmore et al., 2000). The shear zone strikes northwest (-300°), dips —55° to the southwest, and exhibits tonalitic protomylonites and mylonites. The Sheemahant shear zone represents a part of the Late Cretaceous eastern Waddington thrust belt (Rusmore et al., 2000). At the latitude of Bella Coola, the Coast shear zone strikes roughly northwest, and is located approximately 15 to 25 km to the southwest of the PHSZ (Figure 2.1). Reverse movement (northeast side up) on the Coast shear zone between ca. 65 and 55 Ma is reported by Rusmore et al. (2001). A series of subvertical, northwest-trending, ductile shear zones, located to the northwest of Bella Coola, were termed the Jump Across shear zone by Mahoney et al. (2002) and are now referred to as the PHSZ. The shear zones vary in width from a few metres to over a kilometer across, and are exposed between Mount Pootlass and the Dean Channel (Mahoney et al., 2002) (Figure 2.1). Flattening in the shear zones is displayed  20  by boudinaged andesite dykes, attenuated mylonitic bands and flattened mafic enclaves (Mahoney et al., 2002). Protomylonite and mylonite are locally abundant within the shear zones, and kinematic indicators are ambiguous (Mahoney et al., 2002). Throughout the Bella Coola area, abundant north- to northwest-trending brittle faults have resulted in prominent topographic lineaments. The faults cut rocks of all ages and are interpreted to be part of widespread right-lateral brittle faulting throughout the western Canadian Cordillera brought on by dextral transtension from latest Cretaceous to Eocene time (Umhoefer and Schiarizza, 1996; Schiarizza et al., 1997).  2.2 THE POOTLASS HIGH STRAIN ZONE SYSTEM 2.2.1 Introduction The Pootlass High Strain Zone (PHSZ), located within the Intermontane superterrane just east of the Coast shear zone, is a northwest-trending corridor of brittle and ductile deformation exposed in metamorphosed supracrustal rocks of the Stikine terrane and plutonic rocks of the Coast Plutonic Complex. The PHSZ is exposed between Mount Pootlass and the Dean Channel over a strike length of at least 30 km (Figure 2.1). At Mount Pootlass and Falls Camp (Figure 2.1), exposures of the PHSZ are at least 2 km in width. Near the Dean Channel, the PHSZ is anastamosing in its geometry, with zones of high strain generally less than 100 m in width, separated by packages of relatively undeformed rock. The PHSZ is therefore a system of anastamosing high strain zones, herein referred to collectively as the PHSZ. Five fly camp localities within and one outside of the PHSZ are described below. Additional microphotographs of samples collected in the PHSZ are available in Appendix I.  21  2.2.2 Snootli Peak — "Background" Style of Deformation The Snootli Peak locality is characterized by upright, tight to isoclinal, southwestverging folds that provide evidence for horizontal shortening, and a lack of hightemperature non-coaxial strain (Figure 2.2). Snootli Peak thus represents the "background" style of deformation in the Bella Coola area that was subsequently overprinted by the PHSZ. A description of lithologies and structural features from Snootli Peak is provided below.  2.2.2.1 Lithology The Snootli Peak locality includes metasedimentary rocks, andesitic and basaltic metavolcanic rocks, and plutonic rocks ranging in composition from granite to diorite to gabbro (Figure 2.2). Metasedimentary rocks in the Snootli Peak area are characterized by a very intense rusty weathering color and consist of very fine-grained and very finely laminated mudstone and siltstone with minor pebble conglomerate and lapilli tuff. Amphibole- and biotite-rich mafic layers are intercalated throughout the metasedimentary rocks. Metavolcanic packages are andesitic to basaltic in composition and are composed of lapilli tuffs and flows, ranging in thickness from 2 cm to 3 m, with thin fine-grained, dark green, mafic interlayers. Volcanic rocks are fractured and locally pervasively bleached. Many sills and dykes, ranging in composition from aplite to diabase, crosscut the volcanic package.  22  Based on these descriptions, metasedimentary and metavolcanic rocks of the Snootli Peak locality are interpreted to be a part of the Lower to Middle Jurassic strata of the Hazelton Group (Haggart et al., 2003). Muscovite-rich granite exposed at Snootli Peak is well-foliated, medium-grained, and exhibits large quartz eyes and feldspar grains, some of which are flattened. Mafic enclaves composed predominantly of chlorite are also flattened. Very fine-grained felsic sills (20 to 30 cm in width) occur within the granite, as well as mafic sills (5 cm to 1 m thick) composed of green fine-grained chlorite with quartz and feldspar phenocrysts. Foliated diorite occurs over a significant proportion of the centre of the mapped area (Figure 2.2). This unit is composed predominantly of medium- to coarse-grained hornblende, biotite, quartz, and feldspar with occasional epidote-rich patches. Undeformed, dark grey to black, medium- to very coarse-grained, magnetic gabbro occurs in two localities of the map area (Figure 2.2).  2.2.2.2 Structural Geology Bedding (So) in the supracrustal rocks at Snootli Peak has an average strike of 339 and a dip of 65° to the northeast (Figure 2.3a). Southwest-verging, upright, closely spaced, tight to isoclinal folds (F 1 ) are common. Fold axes in the central mapped area generally trend towards the south, with plunges ranging from 10 to 30° (Figure 2.3b). However, in spectacularly folded metasedimentary rocks towards the western end of the mapped area (Figure 2.4a), folds have a northerly trend and plunge approximately 20°. In addition to folding, horizontal shortening is also recorded by boudinage of mafic layers within metasedimentary and  23  metavolcanic rocks with wavelengths of approximately 1 m (Figure 2.4b). Conjugate kink bands in metasedimentary rocks are also indicative of horizontal shortening. Gently undulating folds (F 2 ) are well-developed in the metasedimentary rocks and overprint southwest-verging (F1) folds (Figure 2.4c). F2 fold axes trend towards roughly 060 with a plunge ranging from 70 to 80° (Figure 2.3b). Foliation in supracrustal and plutonic rocks is subparallel bedding (S o ) and to F 1 axial planes, and therefore termed S i axial planar foliation. S 1 is defined by flattened phyllosilicates + quartz + feldspar ± hornblende, and is a continuous schistosity in plutonic rocks and a continuous cleavage in supracrustal rocks. Intersection lineations between bedding and foliation generally trend towards 150 with southward plunges ranging from 5 to 30° (Figure 2.3b). At the western end of the mapped ridge, intersection lineations between S o and S 1 in metasedimentary rocks have a northerly trend, and a plunge of approximately 5°. Late brittle, dextral faults with foliated chlorite cataclasite occur parallel to the foliation (S i ). The protolith of the foliated cataclasite is strongly masked by deformation, however it is interpreted to be mafic metavolcanic rock based on the mafic composition of the cataclasite. A dextral sense of movement is provided by quartz and carbonate shear bands within the cataclasite (Figure 2.4d). Evidence for high-temperature non-coaxial strain at the Snootli Peak locality is not observed.  24  2.2.2.3 Petrology Greenschist facies metamorphism of supracrustal rocks at Snootli Peak is indicated by the following metamorphic mineral assemblage in andesitic and basaltic metavolcanic rocks: chlorite + biotite + muscovite + plagioclase (Yardley, 1989) (Figure 2.5a). Garnet has not been observed at the Snootli Peak locality. Chlorite occurs as long fibers (up to 2 mm in length) and is concentrated along seams of very fine-grained biotite and muscovite, which define a weak to locally moderately well-developed foliation (S i ) (Figure 2.5a). Medium-grained feldspar (up to 1 mm in width) is weakly altered by very fine-grained flakes of chlorite ± sericite that displays no shape preferred orientation.  2.2.2.4 Deformation Microstructures Quartz is fine-grained (generally < 0.5 mm wide), with serrated grain boundaries, and commonly occurs in quartz ribbons (Figure 2.5b). Feldspar grains display patchy extinction and deformation twins (Figure 2.5b). Hornblende shows evidence of patchy extinction. Pressure shadows composed of very fine-grained chlorite ± muscovite ± biotite (Figure 2.5b) and mica-rich seams (Figure 2.5c) in metavolcanic rocks from Snootli Peak are the result of pressure solution, and provide evidence for the presence of fluids during deformation (Passchier and Trouw, 2005). The microstructures described above indicate that quartz underwent dynamic recrystallization by grain boundary migration, whereas feldspar and hornblende deformed by dislocation glide and deformation twinning. Based on these deformation mechanisms rocks at Snootli Peak likely deformed at temperature between 350 and 450°C (Passchier and Trouw, 2005).  25  Coaxial strain at Snootli Peak is recorded in plutonic and supracrustal rocks by mantled porphyroclasts of amphibole and feldspar, with symmetrical tails of dynamically recrystallized quartz ± biotite ± chlorite ± muscovite (Figure 2.5b and c).  2.2.3 Mount Pootlass — The Type Locality for PHSZ Style of Deformation 2.2.3.1 Lithology The southern ridge of Mount Pootlass is dominated by a succession of finely laminated, well-foliated and isoclinally folded metasedimentary rocks, with interlayers of dacitic to andesitic lapilli tuff and flows (Figure 2.6). Metasedimentary rocks consist of pebble conglomerate and sandstone and more tightly laminated siltstone, mudstone and chert. The metasedimentary package is intercalated with very felsic, fine-grained, highly strained rocks (possibly rhyolite), and with amphibole-rich mafic dykes and sills that are folded with the rest of the metasedimentary package. Metasedimentary rocks on most of the southern ridge appear to have reached greenschist facies metamorphism, with foliation defined by abundant chlorite, biotite, and muscovite. However, the metasedimentary rocks on the uppermost part of the ridge, near the contact with intrusive rocks described below, appear to have reached amphibolite facies, as indicated by abundant fine-grained hornblende (Figure 2.6). The contact between the metasedimentary package and the intrusive rocks described below is hidden under permanent snow pack. Based on the above description, and a U-Pb age from this study that will be discussed in Chapter 2.4, the metasedimentary package on Mount Pootlass is interpreted to be a part of the middle strata of the Hazelton Group (Haggart et al., 2003).  26  A large undeformed pluton ranging in composition from diorite to gabbro with abundant enclaves including two large (10 x 20 m) rotated metasedimentary rafts is located at the south end of the southern ridge (Figure 2.6). This pluton is interpreted by Haggart et al. (2006) to be a part of the 118-124 Ma Desire Plutonic Suite. The eastern ridge of Mount Pootlass is composed of foliated biotite hornblende granite with sparse epidote, muscovite and fine-grained garnet (Figure 2.6). The two mica granite with garnet is indicative of partial melt of the crust (Winter, 1998), and suggests this unit is likely an S-type granite. This unit is interpreted to be a part of the 118-124 Ma Desire plutonic suite (Haggart et al., 2006). Towards the eastern end of the ridge a zone of very strongly foliated granite coincides with a thick interval of interlayered, foliation-parallel felsic and mafic plutonic rocks that are separated from each other and from the foliated granite by sharp contacts (Figure 2.7a). The mafic plutonic layers are medium- to fine-grained and are composed predominantly of biotite, feldspar, hornblende and chlorite. The felsic layers are medium- to fine-grained and contain predominantly quartz and feldspar with rare garnet. Felsic and mafic layers have the geometry of foliation-parallel sheeted intrusions with thicknesses ranging from approximately 15 cm to 1.5 m. These sheeted intrusions are tightly folded, which will be discussed below. A 30 m wide package of fine-grained, finely laminated metasedimentary rocks are interlayered with the foliated granite near the middle of the eastern ridge (Figure 2.6). This package of metasedimentary rocks is likely a raft, as seen in the southern ridge; however, it does not appear to have been rotated. At the east end of the eastern ridge, the PHSZ is truncated by an undeformed, coarse-grained pluton composed of quartz, feldspar, muscovite and biotite, which is  27  interpreted to be a part of the 67-73 Ma Four Mile plutonic suite. At the juncture of the eastern and southern ridges on Mount Pootlass a small plug of coarse-grained magnetic gabbro is in intrusive contact with the granite to the east, and with the metasedimentary rocks of the southern flank of Mount Pootlass to the southwest (Figure 2.6). The peak of Mount Pootlass is composed of foliated granodiorite and diorite with sheeted mafic intrusions. Foliation at the summit appears to be mostly magmatic in origin, with medium- to coarse-grained biotite and hornblende defining a moderately well-developed foliation (Figure 2.8d).  2.2.3.2 Structural Geology Coaxial Strain Bedding (So) in the metasedimentary package is subparallel to foliation (ST, see below), as seen at Snootli Peak. Intersection lineations between bedding and foliation are widespread, with an average trend of 130 and a subhorizontal plunge (Figure 2.9b). Metasedimentary rocks on the southern ridge of Mount Pootlass display southwest-verging, upright, very closely spaced, tight to isoclinal folds (Figure 2.7b), here termed F 1 . Fold axes trend towards approximately 140 and are predominantly subhorizontal to southeasterly plunging. The "sheeted" intrusive rocks at Mount Pootlass exhibit several generations of folding. The most well developed and dominant folds are southwest-verging, upright, closely-spaced, and tight to isoclinal with subvertical western limbs and steeply eastward-dipping eastern limbs (Figure 2.7c). Fold axes trend towards approximately 140 and are predominantly subhorizontal to southeasterly plunging (up to 25°)(Figure 2.9b). These isoclinal folds (F T ), are a composite of F1 and F2 folds that  28  combine to form Type 3 interference patterns (Ramsay and Huber, 1983) generally associated with progressive deformation (Figure 2.7c). FT folds are overprinted by gently undulating folds (F3) with wavelengths on the order of several metres, and near vertical fold axes with a subvertical axial surface striking roughly 215 (Figure 2.9b). In some localities the F3 folds are observed folding the limbs and the hinges of the FT folds. In addition to folding, horizontal shortening is also accommodated by boudinage of mafic layers within the metasedimentary package and foliated granite. Boudinage layers are formed within the main foliation (ST)(see below) and are locally deformed by F3.  All rocks on Mount Pootlass, excluding undeformed plutons, exhibit a subvertical foliation striking approximately 320 (Figure 2.9a), and oriented parallel to FT axial planes. This geometry indicates that the foliation is an axial planar foliation here termed ST. Foliation is defined by aligned and elongated quartz + biotite ± amphibole ± feldspar ± muscovite ± chlorite, and is a continuous schistosity in plutonic rocks and a continuous cleavage in metasedimentary rocks. In addition, foliation is defined by alternating mafic (biotite, hornblende) and felsic (quartz, feldspar) sheeted intrusions. ST is especially well developed in granite towards the east end of the eastern ridge, and also in granite near the contact with the metasedimentary rocks of the southern ridge.  Non-Coaxial Strain On horizontal surfaces, perpendicular to the foliation, ductile kinematic indicators in the foliated granite and metasedimentary rocks provide evidence for a predominantly  29  sinistral sense of movement. Kinematic indicators observed consist of (i) drag folds in both metasedimentary rocks and granitic rocks (Figure 2.10a and b), (ii) oblique foliations in mafic, amphibole-rich dykes (Figure 2.10 c), and (iii) C' extensional shear bands in granodiorite (Figure 2.8d). Sparse evidence for dextral ductile non-coaxial strain occurs at the east end of the eastern ridge in the form of brittle-ductile extensional shear bands (Figure 2.10d) in foliated granite. Stretching mineral lineations, defined by elongate (rodded) quartz and feldspar grains in granite, are well developed near the peak of Mount Pootlass, as well as near the east end of the eastern ridge. Mineral lineations trend approximately 140, and are subhorizontal to gently southeasterly plunging, and thus are subparallel to FT fold axes (Figure 2.9b). Brittle faults oriented parallel to foliation occur within plutonic and metasedimentary rocks. Foliated chlorite cataclasite defines the faults and exhibits dextral kinematic indicators, commonly in the form of s-shaped quartz and/or carbonate stringers (Figure 2.7d). These brittle dextral faults are interpreted to be a part of a regionally developed system of latest(?) Cretaceous to Eocene dextral strike-slip faults (Umhoefer and Schiarizza, 1996; Schiarizza et al., 1997), and likely represent the brittle reactivation of sinistral ductile strain corridors.  2.2.3.3 Petrology Metamorphic mineral assemblages on Mount Pootlass indicate a range in metamorphism from mid-greenschist to amphibolite facies.  30  Mid-greenschist facies metasedimentary rocks have a metamorphic mineral assemblage of chlorite + muscovite + biotite + plagioclase (Yardley, 1989) (Figure 2.11a), whereas upper-greenschist facies rocks are composed of the same mineral assemblage plus garnet (Yardley, 1989) (Figure 2.11b and c). Metamorphic chlorite, biotite and muscovite are very fine-grained elongated flakes (< 0.5 mm length), which define the well-developed axial planar foliation (ST). Garnet grains are generally < 1 mm in width and locally have fluid and/or quartz inclusions and/or moderately resorbed edges (Figure 2.11c; Figure 2.12a). Chlorite, biotite, and muscovite flakes wrap around the garnet grains and cluster in pressure shadow or tails parallel to the foliation, indicating that garnet grains are pre- or syn-kinematic (Figure 2.1 lb and c). Plagioclase is weakly altered by randomly oriented fine-grained sericite. On the southeast flank of the peak of Mount Pootlass, metasedimentary rocks reached amphibolite facies metamorphism, with the following metamorphic mineral assemblage: hornblende + plagioclase + epidote (Yardley, 1989)(Figure 2.11d). Elongated hornblende and plagioclase grains define the foliation, along with elongated blades of epidote. Hornblende appears relatively pristine, with local chlorite alteration of grain edges. Feldspar is altered by randomly oriented fine-grained flakes of sericite.  2.2.3.4 Deformation Microstructures Biotite, chlorite and muscovite in all rocks at Mount Pootlass commonly show undulose extinction. Quartz in all rocks is fine-grained (generally < 0.5 mm wide) and exhibits significant internal deformation in the form of undulose extinction, deformation bands, subgrains, and pervasively serrated grain boundaries (Figure 2.12a). Feldspar  31  grains display undulose extinction, subgrains, and deformation twins (Figure 2.11d). Hornblende generally exhibits brittle fracture (Figure 2.11 d), weak undulose extinction, with rare lattice kinking and subgrains. Pressure shadows composed of very fine-grained chlorite ± muscovite ± biotite and mica-rich seams (Figure 2.12a) indicate that pressure solution was an important process during deformation, and indicate the presence of syn-tectonic fluids (Passchier and Trouw, 2005). The microstructures described above indicate that across all rock types on Mount Pootlass quartz underwent dislocation creep and dynamic recrystallization by grain boundary migration, whereas feldspar deformed predominantly by deformation twinning and dislocation glide, with minor dislocation creep. Hornblende also deformed by dislocation glide and deformation twinning. Based on these deformation mechanisms, rocks at Mount Pootlass likely deformed at temperatures between 500 and 700°C (Passchier and Trouw, 2005). Plutonic rocks, consisting primarily of granite and tonalite exhibit sinistral microstructural kinematic indicators, whereas metasedimentary and metavolcanic rocks show evidence of both sinistral shear and coaxial flattening. Coaxial flattening in metasedimentary and metavolcanic rocks is manifested by mantled porphyroclasts with symmetrical tails. These include: flattened feldspar porphyroclasts with tails of fine-grained feldspar ± dynamically recrystallized quartz ± chlorite ± muscovite ± biotite (Figure 2.12b), garnet porphyroclasts with tails of biotite ± dynamically recrystallized quartz ± chlorite, and hornblende with tails of hornblende ±  32  chlorite ± biotite (Figure 2.12c). Conjugate kink bands with slip along fine-grained phyllosilicate minerals are also indicative of coaxial flattening (Figure 2.12d). Sinistral ductile non-coaxial strain in metasedimentary and plutonic rocks most commonly occurs in the form of C' extensional shear bands with slip along fine-grained chlorite or biotite, and a-type porphyroclasts of feldspar or quartz with asymmetrical tails of dynamically recrystallized quartz ± chlorite ± muscovite ± biotite (Figure 2.13a). Garnet also occurs as a-type porphyroclasts with tails of biotite ± chlorite (Figure 2.13b), and rare amphibole a-type porphyroclasts occur with tails of fine-grained amphibole and biotite. Additional microstructural indicators of sinistral non-coaxial strain include chlorite and muscovite mineral fish (Figure 2.13c), drag folded quartz stringers, feldspar domino boudins with dynamically-recrystallized quartz-filled dilational sites (Passchier and Trouw, 2005), and 6-type feldspar porphyroclasts with tails of muscovite ± dynamically recrystallized quartz (Figure 2.13d). Rare 6-type amphibole porphyroclasts also occur with tails of fine-grained amphibole, chlorite and biotite. Dextral non-coaxial strain is indicated by quartz shear bands (Figure 2.13e) in foliated chlorite cataclasite from brittle faults orientated parallel to foliation that occur within plutonic and metasedimentary rocks, as described above (see Structural Geology section).  2.2.3.5 Interpretation Field observations do not provide a clear interpretation of the relative timing of coaxial and high-temperature non-coaxial strain due to the subparallel nature of fold axes and stretching mineral lineations. However, drag folded layers in folded  33  metasedimentary and plutonic rocks (described above) suggest that non-coaxial strain overprinted coaxial fabrics. The relative timing of coaxial and non-coaxial strain will be discussed further in the context of geochronology data presented in Chapter 2.4. Most of the metasedimentary rocks at Mount Pootlass reached peak metamorphism of mid- to upper greenschist facies. Metamorphic phyllosilicates define a well-developed axial planar foliation, form asymmetrical tails on sinistral a- and 8porphyroclasts, and form sinistral C'extensional shear bands, indicating that metamorphism was coeval to horizontal shortening and ductile sinistral non-coaxial strain. Foliation wraps around relatively pristine garnet grains, indicating that garnet is pre- or syn-kinematic. Metasedimentary rocks near to the contact with plutonic rocks on the southeast flank of the peak of Mount Pootlass reached amphibolite grade, which is likely due to contact metamorphism brought on by syn-kinematic magma emplacement in that area. In amphibolite-grade metamorphic rocks, elongated hornblende, plagioclase, and epidote grains define the axial planar foliation and sinistral amphibole a-porphyroclasts occur with tails of fine-grained amphibole and biotite, indicating that amphibolite facies metamorphism was coeval with both horizontal shortening and sinistral ductile noncoaxial strain. Deformation mechanisms interpreted from microstructural analysis indicate that deformation in all rock types on Mount Pootlass occurred at temperatures between 500 and 700°C, which accords with the predicted temperature range for upper greenschist to amphibole facies metamorphism (Yardley, 1989). There does not appear to be any significant variation in deformation mechanisms for quartz, phyllosilicates, and feldspar  34  within mid- to upper-greenschist and amphibolite facies rocks. This is likely due to a requirement of very high temperatures of deformation (> 700°C) before feldspar will show significant dynamic recrystallization, and recovery in quartz will be rapid enough to cause recrystallization of relatively strain-free grains (Passchier and Trouw, 2005). Deformation microstructures exhibited by minerals from voluminous biotitehornblende granite of the Desire plutonic suite on the eastern ridge of Mount Pootlass indicate solid-state deformation, and therefore suggest abundant pre-kinematic plutonism. At the east end of the eastern ridge and on the southeast flank of the peak of Mount Pootlass, zones with particularly well-developed foliation in pre-kinematic granite coincide with swarms of foliation-parallel, syn-kinematic intrusive sills of rhyolite, granite, and basalt (Figure 2.8a). This relationship between high strain and syn-kinematic melt indicates that thermal weakening was an important strain-softening mechanism that enhanced strain localization within the PHSZ. Also on the southeast flank of the peak of Mount Pootlass, 1-tectonite occurs in foliated granite near to the contact with the metasedimentary package. The 1-tectonite exhibits rodded quartz and feldspar grains and a lack of foliation (Figure 2.8b). The formation of 1-tectonite requires exceptionally weak rock and a large component of simple shear (Sullivan, 2006), and therefore suggests that syn-kinematic magmatism thermally weakened the PSHZ during the accommodation of non-coaxial strain. Plutonic rocks on the southeast flank of the peak of Mount Pootlass exhibit melt injection and flame structures such as pinched out and warped mafic enclaves (Figure 2.8c), indicating that intrusive activity was likely syn-deformational. Furthermore, granodiorite and diorite at the peak of Mount Pootlass displays a magmatic foliation (as mentioned above) in conjunction with weakly developed sinistral C'  35  extensional shear bands (Figure 2.8d), which attest to syn-kinematic emplacement. Postkinematic plutonism is indicated by rare undeformed east-west-trending, crosscutting basaltic dykes. The presence of pre-, syn-, and post-kinematic plutonic rocks on Mount Pootlass suggests a protracted history of magmatism within the PHSZ. Moderate post-tectonic alteration is displayed by randomly oriented fine-grained sericite in feldspar and weak chloritization of hornblende grain margins.  2.2.4 Falls Camp Locality 2.2.4.1 Lithology  The north section of the Falls Camp map displays foliated hornblende-granite interlayered with metasedimentary and metavolcanic rocks (Figure 2.14). Metasedimentary rocks are similar to those exposed on Mount Pootlass, and are primarily composed of finely laminated siltstone, mudstone, and chert. Metavolcanic flows and tuffs are andesitic in composition, with minor interlayered basaltic flows. Foliationparallel felsic (quartz, muscovite) and mafic (hornblende, biotite) intrusive sheeted sills are common in the supracrustal rocks. A large undeformed pluton composed of coarsegrained biotite granite truncates the metasedimentary rocks at the east margin of the north section (Figure 2.14) and is interpreted by Haggart et al. (2006) to be a part the 67-73 Ma Four Mile plutonic suite (Haggart et al., 2006). The south section of the Falls Camp locality is composed predominantly of greygreen, finely-laminated dacitic flows and tuffs that are locally plagioclase-phyric (Figure 2.14). Metavolcanic rocks are intercalated with rusty metasedimentary layers of chert and slaty siltstone with thicknesses of 2 to 5 cm. Metavolcanic layers are 5 to 25 cm thick. Supracrustal rocks are interlayered with foliated granite and aphanitic quartz-rich  36  intrusive sills with sparse garnet. Based on these descriptions, supracrustal rocks at the Falls Camp locality are interpreted to be a part of the middle strata of the Hazelton Group. At the southern end of the map, foliated granite exhibits several foliation-parallel mafic and felsic sheeted intrusions similar to those exposed on Mount Pootlass. Lithologies at the north and south sections do not appear to line up along strike (Figure 2.14). In between the two sections is permanent snow pack and very steep terrain, which could be hiding an offsetting fault.  2.2.4.2 Structural Features Metasedimentary and metavolcanic rocks display upright, tight to isoclinal, southwest-verging folds (F 1 ), as described for Mount Pootlass (Figure 2.15a). In addition to F 1 folds, horizontal shortening is partially accommodated by boudinage in mafic, granitic, and quartz-rich intrusive layers in supracrustal rocks. F2 folds, described as F3 folds for Mount Pootlass, are best developed in metasedimentary rocks (Figure 2.15c). All rocks at the Falls Camp locality, excluding the undeformed pluton in the north section of the map area, exhibit a subvertical foliation (S 1 ) similar to that described at Mount Pootlass, with a strike of 340 (Figure 2.16a), and oriented subparallel to F 1 axial planes. This axial planar foliation is defined by aligned and elongated quartz + biotite ± amphibole ± feldspar ± muscovite ± chlorite, and is a continuous schistosity in plutonic rocks and a continuous cleavage in metasedimentary rocks. Subhorizontal intersection lineations between bedding (S o ) and foliation (S1) trend —325 and are subparallel to F1 fold axes (Figure 2.16b). Sinistral, ductile, non-coaxial strain occurs in supracrustal and plutonic rocks at both the north and south sections of the Falls Camp locality, with the exception of the  37  undeformed pluton at the east margin of the north section described above. As at Mount Pootlass, high strain appears to be particularly localized in zones with abundant foliationparallel felsic and mafic intrusive sills. Ductile, sinistral non-coaxial strain is displayed by the oblique orientation of foliation in mafic intrusive sills within metasedimentary rocks (Figure 2.15b). No mineral stretching lineations, such as the rodded quartz or feldspar described for Mount Pootlass, were observed at Falls Camp. Structural relationships observed in the field for coaxial and high-temperature non-coaxial strain do not provide any clear indication of their relative timing of deformation. Brittle, dextral faults, as described for Mount Pootlass, occur parallel to foliation (Figure 2.15d).  2.2.4.3 Petrology A metamorphic mineral assemblage of chlorite + muscovite + biotite + plagioclase at Falls Camp, as seen on the southern ridge at Mount Pootlass, indicates that metasedimentary rocks reached mid-greenschist facies metamorphism. Garnet occurs very rarely as medium-grained, anhedral, and strongly fractured grains that do not appear to be in equilibrium with the metamorphic mineral assemblage described above. Metamorphic chlorite, biotite and muscovite occur as fine-grained elongated flakes (< 0.5 mm length), which define a wavy foliation (S i ) that wraps around garnet porphyroclasts. Fluid-enabled pressure solution produced pressure shadows filled with phyllosilicates, as seen at Mount Pootlass and Snootli Peak. Feldspar grains at Falls Camp show strong sericitization, which appears to be post-kinematic due to a lack of tectonic fabric defined by the sericite (Figure 2.17c). Carbonate also occurs locally as  38  cement within foliated granite at Falls Camp, and is interpreted to be due to post-tectonic alteration (Figure 2.18d).  2.2.4.4 Deformation Microstructures Quartz at the Falls Camp locality shows strongly undulose extinction, fingershaped (Figure 2.18a) and chessboard (Figure 2.17b) subgrains, serrated grain boundaries (Figure 2.18b), and interfacial angles of —120° (Figure 2.18d). Quartz ribbons, which contribute to defining the axial planar foliation (S 1 ), are also common (Figure 2.18c). Feldspar shows undulose extinction, deformation lamellae and deformation twins. Hornblende in foliated granite displays undulose extinction, lattice kinking and rare subgrains. Rare garnet in metasedimentary rocks displays extensive brittle tensile fractures that are consistently oriented perpendicular to the axial planar foliation (Figure 2.17d). Pressure solution, as recorded by symmetrical pressure shadows of very finegrained chlorite ± muscovite ± biotite, and mica-rich seams, point to the presence of fluids during coaxial deformation as is anticipated for greenschist facies rocks. The microstructures described above indicate that quartz underwent dislocation creep and dynamic recrystallization by grain boundary migration. Quartz ribbons were formed by extreme flattening and/or stretching of large single quartz grains (Passchier and Trouw, 2005). Feldspar deformed by dislocation glide and deformation twinning. Hornblende deformed mainly by dislocation glide and deformation twinning, whereas garnet deformed by brittle fracture. Based on these deformation mechanisms, rocks at Falls Camp likely deformed at temperatures between 400 and 500°C (Passchier and Trouw, 2005).  39  Evidence for horizontal shortening and sinistral non-coaxial strain at the Falls Camp location is very similar to that described above for the Mount Pootlass locality. Horizontal shortening is indicated by conjugate kink bands, with slip along very finegrained mica, and mantled porphyroclasts of feldspar or garnet with symmetrical tails of dynamically recrystallized quartz + chlorite or biotite. Tensile fractures in garnet oriented perpendicular to axial planar foliation are interpreted to be due to strong extension (Shaocheng et al., 1997) parallel to the axial planar foliation that was brought on by horizontal shortening during coaxial strain (Figure 2.17d). Sinistral non-coaxial strain is commonly exhibited by a-type porphyroclasts of feldspar (Figure 2.17c) or quartz (Figure 2.17a and b) with asymmetrical tails of dynamically recrystallized quartz ± chlorite ± muscovite ± biotite; and by sigmoids (Passchier and Trouw, 2005) of dynamically recrystallized quartz with tails of chlorite and dynamically recrystallized quartz.  2.2.4.5 Interpretation Metasedimentary rocks at Falls Camp reached mid-greenschist facies metamorphic grade. Metamorphic chlorite, biotite, and muscovite define the axial planar foliation (S i ) and form the asymmetrical tails of sinistral 6-porphyroclasts. Metamorphism is therefore interpreted to have been coeval to horizontal shortening and ductile sinistral non-coaxial strain, which are therefore interpreted to be roughly synchronous. High strain at Falls Camp is distributed relatively evenly through supracrustal and plutonic rocks, with the exception of the undeformed pluton in the north section. No Type 3 folding interference patterns or mineral stretching lineations were observed at  40  Falls Camp, which suggests that strain was less intense here as compared to Mount Pootlass. This could be due to a decrease in the volume of syn-kinematic plutonic rock at Falls Camp with respect to exposures at Mount Pootlass, which therefore resulted in less thermal strain-softening and therefore less strain accommodation.  2.2.5 Jump Across Locality 2.2.5.1 Lithology The east end of the Jump Across locality is composed of andesitic volcanic flows interlayered with foliated granite (Figure 2.19). The abundance of andesitic flows decreases westward, and represents a gradual contact with an exposure of foliated granite with abundant foliation-parallel mafic intrusive sills. Foliated granite at this locality is interpreted by Haggart et al. (2006) to be part of an undifferentiated complex of plutonic rock that is Jurassic to Cretaceous in age. The centre of the map area is composed of strongly foliated granite juxtaposed by a faulted contact to the west against finely laminated dacitic flows and lapilli tuffs (Figure 2.19). Volcanic rocks immediately to the west of the contact with the foliated granite feature a 50 cm wide layer of banded rhodonite (Figure 2.20a). Rhodonite is an important manganese mineral, which may occur as a result of metamorphism and is commonly associated with metasomatic activity in manganiferous rocks (Sapountzis, 1982). Metavolcanic rocks become more andesitic towards the west, where they gradually are intercalated with metasedimentary rocks similar to those described for the Snootli Peak locality. Bedding-parallel layers of undeformed granite intrude metasedimentary rocks.^Based on this description, the metavolcanic and  41  metasedimentary rocks at the Jump Across locality are interpreted to be a part of the middle strata of the Hazelton Group, which is in agreement with Haggart et al. (2003).  2.2.5.2 Structural Geology  Metasedimentary and metavolcanic rocks are folded similarly to the F 1 folding phase described for Mount Pootlass, however fold axes trend roughly north-south, and predominantly plunge steeply to the south (Figure 2.21b). In addition to F 1 folds, horizontal shortening is recorded by boudinage of metavolcanic rocks, and of mafic sills within foliated granite. F2 folds, as described for Mount Pootlass as F3 folds, are best developed in metavolcanic rocks. Metavolcanic rocks and granite at the Jump Across locality exhibit a subvertical axial planar foliation similar to that described at Mount Pootlass; however, the strike (-350°) is closer to north-south (Figure 2.21a). Axial planar foliation in the granite is especially well developed along the margins of mafic intrusive sills. Ductile, sinistral non-coaxial strain is displayed by sheared lapilli in dacitic lapilli tuffs (Figure 2.20b). High-temperature sinistral strain is localized over a width of — 150 m in the metavolcanic rocks in the centre of the mapped area (Figure 2.19). Metasedimentary rocks at the west end and plutonic rocks as the east end of the mapped area do not display evidence of ductile non-coaxial strain. A brittle, dextral fault, as described for Mount Pootlass, occurs parallel to foliation in granite at the east end of the mapped area (Figure 2.19).  42  2.2.5.3 Petrology Lower greenschist facies metamorphism is indicated by metamorphic muscovite, chlorite and plagioclase in metavolcanic and metasedimentary rocks at Jump Across. Axial planar foliation is defined by metamorphic muscovite and chlorite, as well as by epidote in mafic layers. As was seen in previous localities, pressure shadows and micarich seams at Jump Across indicate that fluids were present during deformation. Feldspar in metavolcanic rocks shows moderate alteration by sericite and clay, whereas hornblende in foliated granite is moderately chloritized.  2.2.5.4 Deformation Microstructures Quartz from the Jump Across location exhibits undulose extinction, deformation bands, and serrated grain boundaries, whereas feldspar displays patchy extinction, subgrains, and deformation twins. These microstructures indicate that quartz deformed by dislocation creep and grain boundary migration, whereas feldspar deformed predominantly by dislocation glide. Taken together, these microstructures are indicative of deformation at temperatures ranging from 350 to 450°C (Passchier and Trouw, 2005). Isoclinal F1 microfolds are visible in metavolcanic rocks from the Jump Across locality (Figure 2.22a) and are indicative of horizontal shortening. Sinistral, ductile non-coaxial strain is recorded in metavolcanic rocks by a-type porphyroclasts of feldspar, quartz, or rhodonite with asymmetrical tails of dynamically recrystallized quartz ± fine-grained muscovite ± chlorite ± rhodonite (Figure 2.22b and c); by domino boudins of blocky feldspar (Figure 2.22d); and by localized C' extensional  43  shear bands. Metasedimentary rocks at the west end of the mapped area do not show any evidence of ductile, non-coaxial strain. Brittle dextral non-coaxial strain is indicated by shear bands of quartz in quartzchlorite cataclasite (Figure 2.22e) from a dextral fault within foliated granite at the east end of the mapped area.  2.2.6 Horseshoe Hill Locality 2.2.6.1 Lithologv Metasedimentary and metavolcanic rocks exposed at the western end of the mapped area (Figure 2.23) are interpreted to be a part of the middle strata of the Hazelton Group (Haggart et al., 2006). Metasedimentary rocks are composed of finely-laminated siltstone, mudstone, and chert, whereas metavolcanic rocks are composed of dark grey, finely laminated andesitic to basaltic flows and lapilli tuffs with interlayered felsic (quartz, muscovite) intrusive sills. The bulk of the mapped area at the Horseshoe Hill locality is composed of very weakly-foliated hornblende biotite granodiorite, which is part of the Jurassic to Cretaceous undifferentiated plutonic complex described by Haggart et al. (2006) (Figure 2.23). Minor foliated chlorite-epidote tonalite and foliated biotite granite occur within a narrow (<100 m wide) strain localization zone, which also includes an abundance of 3050 cm wide mafic sills that occur parallel to foliation.  44  2.2.6.2 Structural Features  Metasedimentary and metavolcanic rocks are folded similarly to the F 1 folding phase described for Mount Pootlass. Fold axes trend 325 and plunge approximately 70° (Figure 2.24b). In addition to F 1 folds, horizontal shortening is exhibited by stretched lapilli within metavolcanic rocks and boudinage of felsic intrusive sills (Figure 2.25a). Weakly developed axial planar foliation in tonalite, granodiorite, and supracrustal rocks is defined by aligned and elongated quartz, biotite, and chlorite and aligned hornblende. Foliation has a strike of 325 and a dip of —85° to the northeast (Figure 2.24a). Ductile, high strain is displayed by flattened mafic enclaves (Figure 2.25b) and well-developed foliation in granite and tonalite over a width of < 100 m in the eastern half of the mapped area. Strain localization in this area is also exhibited by the presence of chlorite ultramylonite. Two additional narrow (< 50 m) zones of high strain occur within metasedimentary and metavolcanic rocks in the western half of the mapped area. High strain in this zone is displayed by exceptionally tight folds (F 1 ) (Figure 2.25c) and by folds and boudinage in especially abundant felsic intrusive sills. Sense of movement, for any of the three narrow ductile strain localization zones, could not be discerned in the field. Two foliation-parallel brittle faults of unknown movement sense separate metavolcanic and metasedimentary rocks in the west from granodiorite to the east and are demarked by chlorite cataclasite, as seen in other field localities.  45  2.2.6.3 Petrology Metasedimentary and metavolcanic rocks at the west end of Horseshoe Hill reached middle greenschist facies metamorphism, as indicated by abundant biotite and chlorite that define the axial planar foliation (Figure 2.26c). Mica-rich seams, as previously described for other localities, indicate that fluids enabled pressure solution during deformation. Feldspar is strongly overprinted by randomly oriented flakes of post-tectonic sericite. 2.2.6.4 Deformation Microstructures Quartz displays undulose extinction, subgrains, serrated grain boundaries, and locally, interfacial angles of 120°. Feldspar shows undulose extinction, subgrains, deformation twins, and lattice kinking. Hornblende displays patchy extinction, rare subgrains, lattice kinking and extensive brittle fracture (Figure 2.26c). Microstructures described above indicate that quartz deformed by dislocation creep and dynamic recrystallization by grain boundary migration. Locally, recovery in quartz was efficient enough to produce partial annealing in weakly foliated granodiorite. Feldspar predominantly underwent dislocation glide and deformation twinning. Hornblende deformed mainly by dislocation glide and brittle fracture. Taken together, these microstructures indicate temperatures of deformation between 350 and 450°C (Passchier and Trouw, 2005). Similarly to what was seen in other fly camp locations, coaxial strain at the Horseshoe Hill locality is displayed by mantled feldspar porphyroclasts with symmetrical tails of dynamically recrystallized quartz.  46  Weak evidence for sinistral non-coaxial strain in the two narrow high strain zones within metasedimentary rocks at the west side of the mapped area include localized C' extensional shear bands with slip along fine-grained biotite and chlorite (Figure 2.26c) and 6-type porphyroclasts of feldspar or hornblende with asymmetric tails of biotite ± dynamically recrystallized quartz. Foliated granite from the narrow zone of high strain in the east half of the mapped area shows moderately convincing evidence for dextral non-coaxial strain in the form of oblique foliation of dynamically recrystallized quartz (Figure 2.26a) and 6-type porphyroclasts of feldspar with asymmetric tails of biotite ± epidote ± dynamically recrystallized quartz. Chlorite ultramylonite from the same zone shows sinistral ductile non-coaxial strain in the form of C'extensional shear bands with slip along chlorite, and a-type porphyroclasts of chloritized feldspar, with tails of fine grained chlorite (Figure 2.26b). This area is interpreted to be a zone of coaxial high strain because both sinistral and dextral kinematic indicators occur.  2.2.7 Mount Cloud Locality 2.2.7.1 Lithology The majority of the Mount Cloud map area is composed of undeformed to very weakly foliated granite, which is a part of the Jurassic to Cretaceous undifferentiated plutonic complex of plutonic rock described by Haggart et al. (2006). The south end of the map area is composed of interlayered metavolcanic rocks and foliated quartz hornblende monzonite with layered felsic intrusions (Figure 2.27). The metavolcanic rocks consist of grey-green, interlayered andesitic flows and tuffs, and are interpreted to be a part of the Lower strata of the Hazelton Group.  47  2.2.7.2 Structural Features Metavolcanic rocks are isoclinally folded similarly to the F 1 folding phase described for Mount Pootlass (Figure 2.28a), but with a north-south axial planar orientation. No suitable exposures of F 1 were found to measure fold axis orientations. Flattened mafic enclaves (Figure 2.28b) and boudinage of layered felsic intrusions in quartz hornblende monzonite also record horizontal shortening. Quartz hornblende monzonite and andesitic volcanic rocks in the south end of the mapped area at Mount Cloud exhibit a moderately well-developed subvertical axial planar foliation with a strike of 005 (Figure 2.29). In plutonic rocks, the foliation is defined by a continuous schistosity, whereas in metavolcanic it is a continuous cleavage. Ductile, non-coaxial strain occurs within a narrow zone (-20 m width) of very finely interlayered metavolcanic rock with thin felsic stringers. Drag folds in metavolcanic layers and felsic stringers indicate a sinistral sense of movement (Figure 2.28c). At least one brittle, dextral fault, as described for previous localities, occurs in metavolcanic rock parallel to foliation. It is not clear whether the emplacement of melt in this area was involved in the localization of high strain, because much of the high strain zone is covered by permanent snow pack.  2.2.7.3 Petrology Metavolcanic rocks at Mount Cloud reached lower greenschist facies metamorphism, as indicated by abundant chlorite, which defines the axial planar foliation, and therefore suggests that metamorphism was coeval to horizontal shortening. Pressure solution appears to have precipitated fine-grained phyllosilicates along Riedel  48  slip surfaces (Figure 2.30a) during deformation. Feldspar shows weak to moderate posttectonic sericitization.  2.2.7.4 Deformation Microstructures Quartz from the narrow zone of high strain at Mount Cloud displays undulose extinction, deformation bands, subgrains and locally serrated grain boundaries. Feldspar exhibits patchy extinction, subgrains and deformation twins, whereas hornblende shows patchy extinction, lattice kinking (Figure 2.30b) and brittle fracture (Figure 2.30a). These microstructures indicate that quartz deformed predominantly by dislocation creep with minor dynamic recrystallization by grain boundary migration, feldspar deformed mainly by dislocation glide and deformation twinning, and hornblende predominantly deformed by brittle fracture. These deformation mechanisms indicate a temperature of deformation between 300 and 400°C (Passchier and Trouw, 2005). Brittle-ductile sinistral non-coaxial strain is recorded by a poorly to moderately well-developed Riedel fabric, with slip along R' and Y surfaces in quartz hornblende monzonite and andesitic volcanic rocks in the high strain zone at the south end of the map area (Figure 2.30a). Undeformed to very weakly foliated granite that composes most of the Mount Cloud map shows no microstructural indications of non-coaxial or coaxial strain and is therefore interpreted to be post-kinematic.  49  2.2.8 The PHSZ: Summary of Observations  Supracrustal rocks in most localities within the PHSZ reached lower to upper greenschist facies metamorphism. On Mount Pootlass, metasedimentary rocks reached amphibolite facies, which is interpreted to be a result of contact metamorphism brought on by adjacent plutonic rocks. In all localities, axial planar foliation and asymmetric shear fabrics (such as the tails of a-type porphyroclasts) are defined by metamorphic minerals, and therefore metamorphism is interpreted to be syn-tectonic. Based on the interpretation of microstructures, the only mineral that underwent dislocation creep with dynamic recrystallization is quartz. Interpreted deformation mechanisms for phyllosilicates, feldspar, hornblende, and garnet are varying degrees of dislocation glide, deformation twinning, and brittle fracture. In conjunction with metamorphic mineral assembles, temperature estimates for deformation range from 500 to 700°C at Mount Pootlass, 400 to 500°C at Falls Camp, 350 to 450°C at Jump Across and Horseshoe Hill, and 300 to 400°C at Mount Cloud. Horizontal shortening is accommodated by well developed upright, tight to isoclinal, southwest-verging folds in all mapped areas. In high strain zones at Mount Pootlass, upright folds are refolded into Type 3 interference patterns that are generally associated with progressive deformation (Ramsay and Huber, 1983), and likely formed due to thermal strain-softening brought on by the emplacement of abundant synkinematic intrusions. Finely laminated metasedimentary rocks in several localities exhibit gently undulating F2 (the same as F3 at Mount Pootlass) folds with steeply plunging fold axes.  50  Ductile, sinistral high strain is widespread in supracrustal and plutonic rocks at Mount Pootlass and Falls Camp, and occurs in zones on the order of 1 to 2 km in width. Fly camp localities in the north (Jump Across, Horseshoe Hill and Mount Cloud) display narrow zones of high strain 50 to 100 m in width that are separated by panels of relatively undeformed rock. Throughout the PHSZ strain localization commonly appears to be spatially correlated with the emplacement of foliation-parallel intrusive sills ranging in composition from basalt to rhyolite. Syn-magmatic deformation at Mount Pootlass is indicated by flames structures, 1-tectonite and magmatic foliation in granodiorite with sinistral C' extensional shear bands (described in section 2.2.3.5). Microstructural kinematic indicators of sinistral ductile strain most commonly consist of a-porphyroclasts of quartz or feldspar with asymmetrical tails of metamorphic chlorite ± muscovite ± biotite and dynamically recrystallized quartz. Pressure solution, enabled by the presence of fluids during deformation, appears to have been active at most localities. Subvertical, brittle, foliation-parallel dextral faults occur throughout the PHSZ and are commonly demarked by foliated chlorite cataclasite with quartz and/or carbonate stringers, which form dextral shear bands. Post-tectonic sericitization of feldspar and chloritization of hornblende is common throughout the PHSZ.  51  2.3 GEOTHERMOMETRY Constraints on the temperature and pressure of deformation in the PHSZ are necessary in order to determine the crustal depth to which these rocks were buried during deformation. As described in the previous section, metamorphic minerals in the PHSZ define the axial planar foliation as well as asymmetrical kinematic indicators, and are therefore interpreted to have recrystallized during horizontal shortening and non-coaxial strain.  2.3.1 Introduction to Garnet and Biotite Geothermometry Fine-grained, subhedral to euhedral garnet is present locally in metasedimentary and plutonic rocks at Mount Pootlass and Falls Camp. Grain rims were microprobed where garnet occurs next to fine-grained biotite that defines the foliation, and the Fe/Mg exchange ratio between the pair was used to determine the temperature of crystallization. The Ferry and Spear experimental calibration of the biotite-garnet geothermometer was used for this calculation (Ferry and Spear, 1978), which assumes an equilibrium state for each mineral pair. The following section provides descriptions of samples analyzed and the results of garnet/biotite thermometry. Sample locations are shown on field maps of each respective locality, and are provided, along with geothermometric methodology and data, in Appendix IL  52  2.3.2 Garnet and Biotite Geothermometry Results and Interpretations  Two samples from Mount Pootlass (PL7 and PL31) and two samples from Falls Camp (FC16 and FC18) were analyzed. Sample PL7 is a syn-kinematic muscovite-chlorite-quartz foliation-parallel felsic sheeted intrusion in foliated granite within the strain localization zone on the east end of the eastern ridge of Mount Pootlass (Figure 2.6). Igneous biotite and garnet in this sample are relatively fresh, and help define the axial planar foliation (Figure 2.31a), as well as sinistral kinematic indicators such as a-type porphyroclasts. Some garnet grains have fluid inclusions and resorbed margins, (Figure 2.31a) which were avoided during analysis. This sample yielded an igneous crystallization temperature of 537°C (a [standard deviation] = 63°C). This low crystallization temperature may be due to reequilibration of Fe and Mg between garnet and biotite due to post-crystallization heating via other plutonic activity in the vicinity. Sample PL31 is a chlorite-biotite schist, a greenschist-facies metasedimentary rock from the southern ridge of Mount Pootlass (Figure 2.6) with metamorphic biotite and garnet. Garnet in this sample is euhedral, and contains sparse fluid and quartz inclusions (Figure 2.3 1 b). Biotite is moderately chloritized (Figure 2.3 1 b), and therefore only the most chlorite-free biotite flakes were analyzed. This sample yielded a greenschist metamorphism temperature of 565°C (a = 42°C). Sample FC 16 is a foliation-parallel mafic sill from within greenschist facies metasedimentary rocks in the north section of the mapped area at Falls Camp (Figure 2.14). Garnet in this sample contains fluid and quartz inclusions and moderately resorbed grain edges (Figure 2.31 c), which were avoided during analysis. Biotite occurs as very  53  fine-grained flakes that define the axial planar foliation (Figure 2.31c). This sample yielded a crystallization temperature of 585°C (a = 24°C). Sample FC18 is a felsic sheeted intrusion emplaced parallel to axial planar foliation in greenschist-facies metamorphic rocks at Falls Camp (Figure 2.14). Igneous euhedral garnet and elongate biotite flakes appear pristine (Figure 2.31 d) and define the axial planar foliation in this rock. This sample yielded an igneous crystallization temperature of 722°C (o = 25°C). The high crystallization temperature of this rock is attributed to its close proximity to a large granitic pluton which truncates the metasedimentary package only —100 m to the east (Figure 2.14) and is interpreted to be the magmatic source of the felsic sill.  2.3.3 Introduction to Amphibole and Plagioclase Geothermometry Mafic samples from the PHSZ, with hornblende and plagioclase that occurs in contact and equilibrium with one another, were selected to determine the pressure and temperature of crystallization using the Holland and Blundy method (Holland and Blundy, 1994). Grain rims of relatively pristine hornblende and plagioclase pairs were microprobed. The Holland and Blundy method assumes an equilibrium state for each mineral pair, and utilizes the chemical composition hornblende, and the albite content of plagioclase to determine the temperature and pressure of crystallization. The following section provides descriptions of samples analyzed and the results of hornblende/plagioclase thermometry. Sample locations are shown on field maps of each respective locality, and are provided, along with geothermometric methodology and data, in Appendix II.  54  2.3.4 Amphibole and Plagioclase Geothermometry Results and Interpretations  Three samples from Mount Pootlass (PL2, PL9 and PL28), one sample from Falls Camp (FC16), one sample from Horseshoe Hill (HH2), and one sample from Mount Cloud (MC8) were analyzed. Sample PL2 is a mafic layer within amphibolite-grade metasedimentary rocks on the southern ridge of Mount Pootlass (Figure 2.6). Metamorphic hornblende and plagioclase are strongly elongated parallel to the foliation in this rock, and are relatively free of alteration (Figure 2.32a). This sample yielded an amphibolite metamorphic temperature of 731°C (a = 16°C) and pressure of 6.4 kbar (a = 1.7 kbar). Sample PL9 is a mafic sill emplaced parallel to foliation in granite within a strain localization zone at the east end of the eastern ridge of Mount Pootlass (Figure 2.6). Igneous hornblende and plagioclase are strongly elongated and define the foliation in this rock (Figure 2.32b). Both hornblende and plagioclase appear relatively free of alteration (Figure 2.32b). This sample yielded a crystallization temperature of 707°C (a = 23°C) and pressure of 6.3 kbar (a = 1.6 kbar). Sample PL28 is a mafic sill within amphibolite-grade metasedimentary rocks on the southern ridge of Mount Pootlass (Figure 2.6). Hornblende and plagioclase are interpreted to be igneous, and occur as blocky laths (Figure 2.32c) that define the axial planar foliation in this rock. Both appear alteration free, with only very minor sericite replacement in plagioclase. This sample yielded a crystallization temperature of 640°C (a = 18°C) and pressure of 4.5 kbar (a = 1.6 kbar). Sample FC 16 is a foliation-parallel mafic sill from within greenschist facies metasedimentary rocks in the north section of the mapped area at Falls Camp (Figure  55  2.14). Hornblende and plagioclase are anhedral, with strongly resorbed grain boundaries (Figure 2.32d). However, the minerals appear relatively pristine within the grain margins. The sample yielded a crystallization temperature of 719°C (a = 19°C) and pressure of 5.8 kbar (a = 1.4 kbar). Sample HH2 is a weakly foliated hornblende-biotite granodiorite from Horseshoe Hill that is juxtaposed against highly-strained metasedimentary rocks to the west by a faulted contact (Figure 2.23). Igneous, medium- to coarse-grained hornblende and plagioclase in this sample appear reasonably pristine, with moderate grain boundary resorption (Figure 2.32e). This sample yielded a crystallization temperature of 727°C (a = 16°C) and pressure of 7.4 kbar (a = 2.4 kbar). Sample MC8 is foliated granodiorite from the margin of the strain localization zone on Mount Cloud (Figure 2.27). Igneous hornblende and plagioclase are mediumgrained and subhedral (Figure 2.32f). Grain surfaces of hornblende appear pitted, and are altered by chlorite. Plagioclase shows strong post-tectonic sericite alteration (Figure 2.32f). This sample yielded a crystallization temperature of 660°C (a = 41°C) and pressure of 7.7 kbar (a = 2.8 kbar). However, because of strong alteration of both amphibole and plagioclase in sample MC8 this result is based on the analysis of two mineral pairs and is therefore not considered reliable. Results of amphibole/plagioclase geothermometry described above yield crystallization temperatures of —700°C and pressures of —6.3 kbar, which translates to a reasonable magmatic arc geothermal gradient of —30°C/km depth. As a comparison, modeled geothermal gradients for the currently active Andean and Cascade magmatic arcs are —30-35°C/km in the upper 35 km of the crust (Morgan, 1984; Giese, 1994).  56  Assuming a "normal" lithostatic gradient of 0.27 kbar/km (Twiss and Moores, 1992), crystallization pressures of —6.3 kbar were attained at depths of —23 km. Recent geophysical data presented by Calkins et al. (2006) from a seismic survey conducted in the Bella Coola area indicate that the present interface between the lower crust and the upper mantle occurs at — 32 km. Therefore, by extrapolation it is possible that amphibole/plagioclase crystallization occurred in the lower and more likely mid-crust. The brittle-ductile transition is defined by the temperature at which quartz and feldspar, the main mineralogical components, begin to deform predominantly by dislocation glide, which is —300 to 350°C (Passchier and Trouw, 2005; Dragoni and Pondrelli, 1991). With a geothermal gradient of —30°C/km, the brittle-ductile transition in the PHSZ would have been between 10 and 11.5 km depth. Amphibole/plagioclase pressure and temperature data thus indicate that crystallization in the PHSZ occurred well below the brittle-ductile transition.  2.4 GEOCHRONOLOGY 2.4.1 U-Pb Isotopic Dating Folded, boudinaged, and/or sinistrally sheared foliation-parallel felsic sills occur in supracrustal and plutonic rocks throughout the PHSZ. Zircon from a thin felsic sill (PL40) within greenschist-facies metasedimentary rocks on the southern ridge of Mount Pootlass (Figure 2.6) was dated using the U-Pb laser ablation ICP-MS method. The sill is composed of foliated granite that has undergone ductile sinistral non-coaxial strain and is therefore interpreted to be pre- or syn-kinematic. Sample PL40 yielded a U-Pb zircon crystallization age of 114.2 ± 2.0 Ma (Figure 2.33). A sample description and photograph are available in Appendix III, along with U-Pb data and procedures.  57  Haggart et al. (2006) report a U-Pb crystallization age of 140.0 ± 1.0 Ma for a foliation-parallel, quartz-phyric, rhyolitic dyke within the metasedimentary package on the southern ridge of Mount Pootlass. These ages indicate that the metasedimentary package on the southern ridge of Mount Pootlass is older than 140 Ma, and supports the interpretation that they are a part of the Lower(?) to Middle Jurassic Hazelton Group (Diakow et al., 2002).  2.4.2 40Ar/39Ar Isotopic Dating 40^39  Ar/ Ar cooling ages of biotite, hornblende, and muscovite from various  deformed supracrustal and plutonic rocks were used to constrain ages of deformation in the PHSZ. 4°Ar/ - Ar closure temperatures for analyzed minerals are: hornblende, 550°C; 39 muscovite, 370°C; and biotite, 360°C (Hodges, 2003). 40 Ar/39 Ar data, methodology, data, sample descriptions and locations are available in Appendix III. The following section provides sample descriptions and results of 40 Ar/39 Ar isotopic dating.  2.4.2.1 Age Constraints for Coaxial Strain Sample SS3 was collected from greenschist-facies metasedimentary rocks at Snootli Peak that exhibit upright, tight, south-west verging folds (F1) and no ductile noncoaxial strain (Figure 2.2). Metamorphic biotite, which defines the axial planar continuous cleavage in sample SS3, yielded an  4°Ar/39 Ar  cooling age of 72.70 ± 0.54 Ma  (Figure 2.34). Sample HH1 is a mafic dyke that crosscuts foliated diorite at the Horseshoe Hill locality (Figure 2.23). Foliated diorite is not folded but has undergone coaxial strain (or pure shear), as indicated by the development of a weak continuous schistosity and  58  flattened mafic enclaves. Results for sample HH1 yielded a biotite cooling age of 114.19 ± 0.77 Ma (Figure 2.34).  2.4.2.2 Age Constraints for Non-Coaxial Strain Sample MC 10 is a sinistrally sheared andesitic volcanic tuff from the narrow high strain zone at Mount Cloud (Figure 2.27). Hornblende and biotite define the foliation in this rock, and yielded  40 Ar/39 Ar  cooling ages of 72.72 ± 0.49 Ma, and 76.28 ± 0.55 Ma,  respectively (Figure 2.34). It is not clear why 40Ar/39Ar cooling ages indicate that biotite passed through its closure temperature of 360°C before hornblende passed through its closure temperature of 550°C. However, these ages indicate that sinistral non-coaxial strain persisted at Mount Cloud until at least 73 Ma. Hornblende that defines the foliation in a tightly folded and sinistrally sheared, foliation-parallel, mafic sheeted intrusion (PL30) within foliated granite near the peak of Mount Pootlass (Figure 2.6), yielded an  4° Ar/39 Ar  cooling age of 62.39 ± 0.40 Ma (Figure  2.34). Sample PL31 is a boudinaged, foliation-parallel, thin mafic sill within greenschist-facies metasedimentary rocks (Figure 2.6). Foliation in the mafic sill, which is defined by biotite and hornblende, is obliquely oriented to the foliation in surrounding metasedimentary rock and indicates ductile sinistral non-coaxial strain (Figure 2.10c). Biotite from this sample yielded an 4° Ar/39 Ar cooling age of 76.36 ± 0.82 Ma (Figure 2.34). Biotite and hornblende from an undeformed gabbroic plug (PL3) near the contact between metasedimentary rocks and foliated diorite on Mount Pootlass (Figure 2.6)  59  yielded 40 Ar/ 39Ar cooling ages of 70.66 ± 0.53 Ma and 71.03 ± 0.81 Ma respectively (Figure 2.34). The nature of the contact between the gabbro plug and highly strained metasedimentary and plutonic rocks to the west is unclear due to permanent snow pack in this area. The PHSZ is reportedly truncated near Mount Saunders by a pluton composed of muscovite-biotite granite and assigned to the Four Mile plutonic suite (Haggart et al., 2006; Hrudey et al., 2002), which yielded an  4° Ar/39 Ar  biotite cooling age of 67.2 ± 0.3  Ma (Haggart et al., 2006). Muscovite from a foliation-parallel, dextral brittle fault defined by muscovitequartz cataclasite (PL20) on Mount Pootlass (Figure 2.6) yielded an  40 Ar/39 Ar  cooling  age of 63.33 ± 0.69 Ma (Figure 2.34).  2.4.2.3 Interpretation of 40 Ar/39Ar Cooling Ages 40  Ar/39Ar cooling ages for samples SS3 and HH1 indicate that southwest-directed  horizontal shortening in the PHSZ was protracted, was active prior to 114 Ma, and persisted until at least 73 Ma. Taken together,  40 Ar/39 Ar  cooling ages for samples PL30,  PL31, and MC 10 indicate that sinistral non-coaxial strain within the PHSZ was active from 76 Ma (or earlier) to 62 Ma, and was therefore coeval to the last of the coaxial strain, but persisted, at least in some areas, after coaxial strain had ceased. Coaxial strain is therefore associated with sinistral non-coaxial strain in the PHSZ and may be part of the same protracted deformation event, with sinistral non-coaxial strain being facilitated by the emplacement of syn-kinematic melt, as described for Mount Pootlass. A crosscutting pluton of the Four Mile plutonic suite (described above) near Falls Camp indicates that sinistral high strain ended at this locality prior to 67 Ma, whereas at  60  Mount Pootlass sinistral high strain continued until 62 Ma. An interpretation is that sinistral movement along the PHSZ ceased at some localities along strike while it remained active at others. 40  Ar/39 Ar cooling ages for biotite and hornblende from sample PL3 (undeformed  gabbro plug emplaced in foliated and sinistrally sheared granite) on Mount Pootlass confirms that active melt emplacement occurred within the PHSZ during non-coaxial deformation. It remains unclear why the syn-kinematic gabbro was not deformed by the non-coaxial strain. However, because gabbro is much stronger than granite under the same physical conditions of deformation, it likely acted as a rigid body while deformation was accommodated by the surrounding granite. The muscovite 40Ar/39Ar cooling age (63 Ma) from sample PL20 indicates that brittle dextral faults within the PHSZ were active as ductile sinistral non-coaxial strain was tapering off, and are attributed to a regionally developed system of latest(?) Cretaceous to Eocene dextral strike-slip faults (Umhoefer and Schiarizza, 1996; Schiarizza et al., 1997).  2.5 DISCUSSION  2.5.1 Variation Along Strike All exposures of the PHSZ are characterized by tight to isoclinal, southwestverging folds in supracrustal rocks, intensely foliated granitoids, and tightly folded sheeted intrusions of strongly deformed rhyolite, granite, and basalt that coincide with zones of particularly high strain localization. The PHSZ, in the areas mapped in the south (Mount Pootlass and Falls Camp), is up to 2 km thick of continuous high strain. In  61  contrast, areas mapped in the north (Jump Across, Horseshoe Hill and Mount Cloud), are characterized by several zones of strain localization that are only 50 to 100 m wide, and separated by panels of less or undeformed rock. Exposures of the PHSZ near Mount Pootlass are characterized exclusively by high-temperature intracrystalline deformation at temperatures between 500 and 700°C, whereas in the north PHSZ (Jump Across, Horseshoe Hill, and Mount Cloud), sinistral non-coaxial strain is accommodated at temperatures between 300 and 450°C. Observed variations along strike could be explained by (1) a variation in exposed crustal level, or (2) abundant syn-magmatic deformation. The first explanation suggests that the south PHSZ displays middle crustal deformation, whereas the north PHSZ records middle- to upper-crustal deformation (Passchier and Trouw, 2005), and thus from south to north, exposures represent a cross-section from the middle crust to upper crust through the PHSZ. However, preliminary geothermometric data presented in this study does not indicate any significant variation in temperature or pressure of deformation along strike and additional work is necessary to investigate this hypothesis. The second and more likely explanation for observed variations along strike is that in the south PHSZ the emplacement of abundant syn-kinematic melt in the form of mafic and felsic sheeted intrusions weakened the crust, and allowed for high strain localization over a —2 km wide package of rock. Felsic and mafic sheeted intrusions also occur in the north PHSZ, but do not appear in such concentrated swarms as those seen at Mount Pootlass.  62  2.5.2 The Significance of Syn-Kinematic Melt in the PHSZ Throughout the PHSZ, zones of particularly high strain localization coincide with swarms of syn-kinematic intrusive sills of rhyolite, granite, and basalt that occur parallel to the subvertical foliation. This spatial correlation indicates that significant intrusive activity during deformation acted as a strain softening mechanism that led to the localization of high strain. Hollister and Crawford (1986) suggest that the emplacement of melt into the lower crust leads to the formation of a melt-weakened zones that results in the localization of strain. Under these conditions, strain softening is the product of a thermal anomaly brought on by the emplacement of syn-tectonic intrusive sheets, which favors ductile deformation in the vicinity of syn-kinematic intrusions (Pavlis, 1995). Hollister and Andronicos (2006) also report the facilitation of ductile flow in gneissic country rocks by the voluminous emplacement of subhorizontal sheeted intrusions. This process of melt-enhanced deformation is a significant aspect of the orogenic process, and is particularly important in convergent tectonic regimes (Hollister and Crawford, 1986). For example, in metamorphic and igneous rocks of the Coast Plutonic Complex near Prince Rupert, B.C., Hollister and Crawford (1986) report the localization of synkinematic melt in zones of high strain that are characterized by penetrative shearing and isoclinal folds in schistose metamorphic rocks. Transpression induced crustal thickening in the Coast Mountains near Prince Rupert (ca. —85 to 60 Ma) forced the lower crust down to —55 km depth, where basalt from the mantle heated it to temperatures hot enough for melting (Hollister and Andronicos, 2006). Mahoney et al. (2006) also suggest Late Cretaceous to Paleogene transpression of the Coast Plutonic Complex in the Bella Coola area. The partial melt of  63  the lower crust mixed with basalt from the mantle and was subsequently driven upwards along subvertical transpressional shear zones (Hollister and Andronicos, 2006). A similar model for the exhumation of melt driven by uplift along subvertical shear zones along the margins of the Coast Plutonic Complex was proposed by Crawford et al. (1987). Saint Blanquat (1998) suggests that magmas preferentially intrude transpressional systems because of the steep pressure gradients offered by vertical noncoaxial shear zones. The ability of subvertical shear zones to force magma upwards is due to a combination of magma buoyancy and transpressional dynamics that lead to magma overpressuring, which is efficiently relieved by upward movement along subvertical shear zones (Saint Blanquat, 1998). This process of transpression-induced crustal thickening, partial melting of the lower crust, and upward influx of resulting melt along subvertical, transpressional shear zones suggests a mechanism for the observed abundance of syn-kinematic magma within the PHSZ and illustrates the dynamic relationship between syn-kinematic melt and deformation.  2.5.3 Crustal Delamination The overall intermediate composition of batholiths such as the Sierra Nevadas and the Coast Plutonic Complex are thought to result from magmatic segregation of basaltic primary magmas during batholith generation. This requires that a large volume of ultramafic cumulate material must have accumulated at depth beneath such batholithic complexes; however, in most cases there is little or no evidence that such an ultramafic root is present, implying that it has been removed by some mechanism. Crustal  64  delamination is commonly cited as a mechanism responsible for removing the ultramafic residual roots. Crustal delamination can have significant implications for magma production and emplacement, as well as for the deformation style of the crust. Duchesne et al. (1999) propose a model of "crustal tongue melting" to explain anorthosite melt channeling along lithospheric weaknesses, such as high angle shear zones, in southern Norway. Their model of linear crustal delamination leads to the production of a wide variety of magmas, from granitic to high-alumina basaltic, with subsequent emplacement controlled by subvertical structural features. Pliocene crustal delamination beneath the Sierra Nevada batholith is thought to have caused uplift, extension and shortening of the crust during that time (Jones et al., 2004). The removal of dense lower lithosphere by delamination resulted in crustal uplift and extension brought on by buoyancy driven mantle upwelling. Horizontal shortening was triggered elsewhere in the Sierra Nevadas to accommodate this crustal extension and uplift, and is thought to have resulted in the development of the California Coast Ranges. Crustal delamination in the Sierra Nevadas is also thought to have caused a shift in transform slip distribution from the San Andreas fault to the Eastern California shear zone due to extension and fragmentation of the Sierra-Great Valley microplate. Better constraints on the timing of strain accommodation along these structures are required to support this hypothesis. Zandt et al. (2004) present seismic profiling of crustal delamination in the Sierra Nevadas. Their results indicate the removal of lower lithosphere by shearing along a detachment zone between the lower crust and the mantle. Zandt et al (2004) propose that during the later stages of crustal delamination, the crust remains in a state of extension  65  while downwelling in the mantle produces a region of strong convergence. The juxtaposition of these two processes produces decoupling or viscous shearing along the lower crust/mantle boundary and the formation lower crustal shear zones. Pliocene crustal delamination in the Sierra Nevadas is an example of how this process can have profound effects on intra-plate crustal deformation and on mechanisms of deformation in the lower crust. Mahoney et al. (2006) have suggested that crustal delamination under parts of the Coast Plutonic Complex in Late Cretaceous time may have coincided with the termination of typical subduction-related magmatism in the belt, as well as the widespread emplacement of crustally derived granites of the 73-67 Ma Four Mile plutonic suite. A model involving linear crustal delamination could be applied to a portion of the Coast Plutonic Complex to explain the preferential emplacement of abundant syn-kinematic melt within the PHSZ. Crustal delamination beneath the Coast Plutonic Complex in the Late Cretaceous could have played a role in the formation of the PHSZ according to the model proposed by Zandt et al. (2004), and may also have contributed to horizontal shortening accommodated by the crust at this time. Petrological and geochemical studies of the Coast Plutonic Complex with an aim to investigate the possibility of crustal delamination are currently in their preliminary stages (Wetmore et al., 2004).  66  2.5.4 Deformation Models for the PHSZ What is the significance of the PHSZ and, given that movement occurred between 76 (or earlier) and 62 Ma, to what other structures is it potentially related? Three models may be applicable when considering the formation of the PHSZ: (1) sinistral transpression, (2) flattening induced conjugate shear zones, and (3) sinistral extensional step-overs.  2.5.4.1 Sinistral Transpression In a transpressive setting brought on by oblique subduction, convergence is commonly partitioned into a compressive stress and a transcurrent stress (Saint Blanquat, 1998). Compressive stress is typically accommodated by arc-normal contraction whereas transcurrent stress is generally accommodated by strike-slip movement within the magmatic arc (Saint Blanquat, 1998). High heat flow in the arc, predominantly due to the migration of melt, induces a zone of weakness that allows for substantial transcurrent motion (Saint Blanquat, 1998). Transcurrent strain partitioning in magmatic arcs has been widely reported, with examples provided by the Sumatra and Cascade magmatic arcs (Weaver et al., 1987; Tikoff and Teyssier, 1994), which indicate that transcurrent strain partitioning may occur even at very high convergence angles (85° for Cascadia subduction zone) (Saint Blanquat, 1998). At the latitude of Bella Coola, the Sheemahant northeast-verging thrust was active between 91 and 54 Ma (Rusmore et al., 2000), and the Coast shear zone is interpreted to have been active as a southwest-verging thrust from 65-55 Ma (Rusmore et al. 2001). In the Bella Coola area, the Coast shear zone strikes —310, and the Sheemahant shear zone  67  strikes —300. These two structures are therefore oriented roughly 20 to 30° to the west with respect to the PHSZ (Figure 2.35) and are roughly parallel to the convergent western North American margin. Under sinistral transpression, the geometry of these structures would allow for compressive stress to be accommodated by thrusting on the Sheemahant and Coast shear zones, and sinistral transcurrent stress to be accommodated by the PHSZ (Figure 2.36). Oblique convergence of the North American and outboard oceanic plates is interpreted to have switched from sinistral in the earliest Cretaceous to dextral in the Late Cretaceous (Engebretson et al., 1985). Early to mid-Cretaceous sinistral transpression was accommodated along the Grenville, Kitkatla, and Principe-Laredo shear zones near Prince Rupert, B.C. (Chardon et al., 1999) and by the Tchaikazan River area shear zones in southwestern B.C. (Israel et al., 2006). Sinistral transpression in the PHSZ would require that sinistral oblique convergence in the Bella Coola area persisted through Late Cretaceous time. Rusmore et al. (2000) suggest that northeast-verging thrusting along the Sheemahant shear zone between 91 and 54 Ma reinforces the interpretation that mid- to Late Cretaceous arc magmatism in the Coast Mountains was coeval with regionally extensive contractional deformation.  2.5.4.2 Flattening Induced Conjugate Shear Zones A second model to explain sinistral movement along the PHSZ is the development of conjugate shear zones as a result of predominantly orthogonal collision. Northeast- and southwest-vergent thrusts including the Sheemahant and Coast shear zones indicate that compressive stresses were important in the Bella Coola area during the Late Cretaceous. The development of high angle shear zones may also have  68  accommodated horizontal shortening (Brandmayr et al., 1995; Valentino et al., 1995). Under progressive simple shear all material lines tend to rotate towards parallelism with the principal axes of strain (Twiss and Moores, 1992), and thus under high strain one of the two conjugate shear zones could be favored while the other rotates into parallelism or accommodates no displacement (Figure 2.37). Under this model, the PHSZ would represent the favored sinistral component of the postulated conjugate set of shear zones, whereas the dextral conjugate would not have accommodated any significant displacement and may have rotated into parallelism with the PHSZ.  2.5.4.3. Sinistral Extensional Step-Overs Coeval sinistral movement along the PHSZ and the Talchako fault between 76 (or earlier) and 65 Ma indicates that these two structures may be kinematically linked via a step-over (Figure 2.38). This model predicts the development of a negative flower structure in an extensional zone between the PHSZ and the Talchako fault (Figure 2.38). A negative flower structure would be manifested in the field by the presence of a series of extensional high-angle normal faults, and possibly by the intrusion of dyke swarms along extensional fractures. Due to the orientation of the PHSZ and the Talchako fault (strike —330-340°), both the normal faults and dyke swarms would be expected to have a strike of roughly 270-300°. No normal faults with suitable orientations have been mapped between the PHSZ and the Talchako fault; however, dyke swarms recording upper crustal extension appear to be abundant in the Bella Coola area (Mahoney et al., 2002). Further detailed fieldwork is required to resolve dyke swarm orientations that may support this model.  69  A transpressive model that incorporates the PHSZ and the Talchako faults as a step-over system to accommodate the partitioning of sinistral transcurrent stress, while compressive stress is accommodated by the Sheemahant and Coast shear zones, satisfies the observations recorded in this research. Sinistral transpression is a convincing model due to the relative orientations of the PHSZ and the Sheemahant and Coast shear zones, as described above, and the evidence for coeval thrusting and sinistral shear. This model does, however, require that sinistral oblique convergence in the Bella Coola area persisted through Late Cretaceous time. To the northwest, the PHSZ may link with the northwest-striking Kimsquit fault, which follows the east edge of the Dean Channel (Figure 2.1). This interpretation is suggested by brittle-ductile sinistral kinematic indicators observed along the Kimsquit fault by Rusmore, (pers. comm. 2007) that are similar to those observed in this study at Mount Cloud. To the southeast, the PHSZ likely continues at least to Mount Saugstad, just east of the Snootli Peak locality. Haggart et al. (2006) have reported several undifferentiated shear zones in this area; however, the terrain on and around Mount Saugstad is especially extreme and snow covered, and therefore was not explored during this research. Alternatively, as suggested above, transcurrent motion accommodated along the PHSZ may have been transferred to the Talchako fault via an extensional stepover. This model would suggest that the PHSZ terminates near or within the Bella Coola valley (Figure 2.1).  70  2.5.5 Summary of Conclusions  The PHSZ records sinistral ductile non-coaxial strain accommodated in Late Cretaceous time. The PSHZ consists of a system of subvertical high strain zones exposed over a northwest-trending strike length of at least 30 km. Baer (1973) and Haggart et al. (2006) have indicated possible extensions of the PHSZ to the north of the Dean Channel and to the south of Bella Coola in the vicinity of Mount Saugstad. The strike length of the high strain zone remains undefined due to the extreme terrain, permanent snow pack, and glaciers characteristic of the Coast Mountains at this latitude. Within the PHSZ, zones of exceptional strain localization are associated with the emplacement of syn-kinematic plutonic rock and especially with an abundance of synkinematic intrusive felsic and mafic sills. This spatial correlation of high strain with coeval melt emplacement suggests that significant intrusive activity acted as a strain softening mechanism during deformation and led to the localization of high strain. Transpression-induced overpressuring of partially melted lower crust, exemplified by the emplacement of two-mica granite with garnet in the PHSZ, may have driven the upward migration of magma, which appears to be intrinsically linked to high strain in the PHSZ. Non-coaxial strain accommodated along the PHSZ is kinematically linked to the Talchako fault, which is also interpreted to have accommodated ductile sinistral movement between 76 (or earlier) and 65 Ma (S. Israel, pers. comm. 2008). The PHSZ and the Talchako fault may be linked as a system of extensional step-overs. Coeval horizontal shortening in the Bella Coola area, recorded by regional southwest-verging folds, and by thrusting along the Sheemahant and Coast shear zones indicates that sinistral transpression persisted in the Bella Coola area throughout the Late Cretaceous.  71  Figure 2.1a o^Geological Setting of the PHSZ with Fly Camp 7) c.c)^Locations. -  5;850,000  Mount 4 Cloud  -  )  ' 'Horseshoe I-1111  (-  modified from: Haggart et al., 2006; Baer, 1973; Mahoney et al., 2002. Map Projection: Nad27 Canada UTM Zone 9. Refer to Figure 2.1b for legend.  1 0 k I Schematic cross section through Bella Coola area and the PHSZ PHSZ  not to scale  see above map for cross section location  72  ^  LEGEND PALEOGENE Egm^Post-tectonic plutons (U/Pb 52-56 Ma, 52-53 Ma) Undifferentiated tonalite, Pg quartz diorite, diorite, granitic orthogneiss LATE CRETACEOUS TO PALEOGENE LKFM Four Mile Plutonic Suite (U/Pb ca. 67-73 Ma) LATE CRETACEOUS LKF^Fougner Plutonic Suite (U/Pb ca. 67-68 Ma) LKBS Big Snow Plutonic Suite (U/Pb ca. 79-95 Ma) EARLY CRETACEOUS EKD^Desire Plutonic Suite (U/Pb ca. 118-124 Ma) ?VALANGINIAN, HAUTERIVIAN-BARREMIAN IKMv Monarch Assemblage, volcanic rocks IKMs Monarch Assemblage, sedimentary rocks JURASSIC TO CRETACEOUS Undifferentiated granodiorite, JKP diorite, and hornblendebiotite tonalite JKF^Firvale Plutonic Suite (U/Pb ca. 131-140, 148-164 Ma) ?PLIENSBACHIAN TO TOARCIAN ^IJHv^Hazelton Group, volcanic rocks  ^1 1111  SYMBOLS  0":1  fault possible shear zones mapped by Haggart et al., 2006 and Baer, 1973.  iwit  IJHs^HazeIton Group, sedimentary rocks  EARLY JURASSIC EJHL Howe Lake Plutonic Suite (U/Pb ca. 182-190 Ma)  ?TRIASSIC TO ?LOWER JURASSIC rJv  permanent snowpack and glaciers  Undifferentiated basaltic and andesitic metavolcanic and volcaniclastic rocks  11-11LA  potential extensions of the Pootlass High Strain Zone  7  * tt  outline of the Pootlass High Strain Zone  ^fly camp location  ^high strain zone  -  Figure 2.1b. Bella Coola Geology Legend.  73  /  3 )  ,68  Map Projection: Nad 27 Canada, UTM Zone 9. Schematic Cross Section of Snootli Peak  Schematic Symbols  V\  fold  \^foliation  B  :1101 see above map for cross section location  not to scale  Figure 2.2a. Snootli Peak Geology and Schematic Cross Section. Located south of Bella Coola, near Mount Saugstad. This area represents the "background" style of deformation in the PHSZ area, and is characterized by upright, tight, southwest-verging folds, and a lack of high-temperature non-coaxial strain. Refer to Figure 2.2b for legend.  74  0 z uJ  0 w  w  ° g  ...7-_. d 0 Ta  -  LL .. -^RI .-'-' (I) ,-- r-^C. )  S  u) 73 o c)^CO C •—^ Cl) '5,^_C) (13 O _E 0_ a^E  E O  O 2.. ..... D^•:,:-, ,  ° -°  4  'P ,L,- .2 „ , -0 (D (7) 4 m 0 al _ .c r 0 2_ 4_ a) -0 . 0_ as , n4-„, k.) 2 (11 0 >, CO (15 Ci) CS) a _Y '•_^U) O y -0 ° a) -  • • " - E  I^0  4-  . 2 2 TD o -E'  0 9  --  . E - 0 -1: " C 0  )  as 92 =^as -_,_-. O a) = — - ui T.-.) ›, a 0 o as—as >as o_ > -t: a) —E r) _9_, 2 0 0 2 .c (73 0  •• I  •• •  111  0 -Q E W >  2  C-7)  CO  •  s-  L.  -  a) p^ 2 a)  CES E  Li= a) (/) E 4E  • O  O 0 0 0 00  (Ts a)^a) " a)  /  Cl Cl ct  cf") Cl  Cl  -  ■C) Cl  C Cl a)  cuto  ct  bi) 4.1 (:)  .  H -d tO  a)  to CS -  N  Cl Cl to  75  (a)^  (b)  Figure 2.3 Snootli Peak Stereonet Diagrams (equal area) (a) (b)  Poles to bedding (S o ) (dot) F 1 fold axis (diamond), F, fold axis (circle), intersection lineation between S o and S I (square)  76  Figure 2.4. Snootli Peak Field Photographs (a) (b) (c)  (d)  Southwest-verging tight folds (F,) in metasedimentary rocks. Red, grey and yellow coloured layers distinguish bedding. Looking northeast. GPS for scale is —15 cm tall. Boudinage of felsic sill within metasedimentary strata. Pen (15 cm long with orange flagging tape) points northwest. F3 fold in metasedimentary rocks. Refolded F, fold hinge is visible on face of lower outcrop. Northwest is to left. GPS for scale is —15 cm long. Dextral shape fabric of quartz stringers in foliated chlorite cataclasite. Pen (15 cm long) points northwest.  77  Figure 2.5. Microphotographs of Rocks from Snootli Peak (a)  Greenschist metamorphic mineral assemblage in metavolcanic andesite: chlorite (chl), plagioclase (plag) and muscovite (muse) Mantled feldspar porphyroclast with symmetrical tails of dynamically (b) recrystallized quartz, biotite and muscovite in felsic intrusive sill within metavolcanic rock; pressure shadow filled with fine-grained mica (c) Mantled feldspar porphyroclast with symmetrical tails of dynamically recrystallized quartz, biotite and muscovite, seams of very fine-grained mica; rock is a felsic intrusive sill within metavolcanic rock.  78  ^-.  U)  0  .c  Co  .  Ts  U)  c c (.0 o co p N 0 a) •?^.:7)  ,,,^ ^ D ..«.-^ . C^-0  r, C7^t  a) c)o .  3 TD  -  a)  Li= CO^,I—  c as c^7;7l!, E  0^  3^o^as •—  CD .4=^Cn^ -1-4 Ci3^-0^ D _C ^-0  a) _c  ,  /^es r■-d  \\:\ \\■,`,\‘  ilill: • •  •  N  .(7)  -  o  a)  0  O 0  E 0  Lc) Ca  Co  Co  -  Cs  CB 0_  0  CU  Co Q  a) U) _o a) O  co  _c . — L.= as  5 0 0  ..... . • ' .......  Co  E  U)  a) E _cU)  Co  Co  _c  • •••;.:^  . .... ., .... .. .....^.....s.:;.S...t.. ... ......  ............... •  C.7.:;S;5;5^ ....... ....  ^‹,-. ^\\‘''^--,  ...  ........ ........ .  a) O  N  2 CB  1*--- L-  c C Co 0) 0 (I)  -  c\ 0 0 _a • (N Z  O U • LL :c1 o_ a) ct  2 (Y  U)  U)  CO O O  a. 0 0 0  U a) C/) U) U)  2 0 0 CB  E  a) _c  79  Figure 2.7. Mount Pootlass Field Photographs Foliation-parallel felsic and mafic intrusive sheets within foliated granite. View to southeast is —1.5 m across. FT folds in finely-laminated metasedimentary rocks on southern ridge. (b) Pen (15 cm long) points northwest. FT folds in mafic and felsic sheeted intrusions at east end of eastern ridge. (c) Hammer handle (20 cm long) points to northwest. Refolded fold (F T ) of thin quartz-rich sill in foliated granite. (d) Pen (15 cm long) points northwest. (e)^Quartz stringers in foliated chlorite cataclasite indicate dextral movement sense of brittle fault. Pen (15 cm long) points to northwest.  (a)  80  Figure 2.8. Field Photographs of Syn-Kinematic Melt at Mount Pootlass (a) (b) (c) (d)  Rodded quartz and feldspar grains and no foliation in 1-tectonite within foliated granite. Pen (15 cm long) points northwest. Thinly layered felsic and mafic intrusive sills with foliated granite at east end of eastern ridge. Field of view is 40 cm in width. Northwest is up. Immiscible felsic and mafic magma. Elongated mafic lenses with flame structures. Hammer handle (20 cm long) points northwest. Magmatic foliation defined by medium- to coarse-grained biotite and hornblende in granodiorite. Weak sinistral C' extensional shear bands extend to bottom left corner of image. Field of view — 30 cm. Northwest is to right.  81  Figure 2.9. Mount Pootlass Stereonet Diagrams (equal area) (a) (b)  Poles to foliation (S T ) (dot) FT fold axis (triangle), intersection lineation between S o and ST (square), mineral stretching lineation in quartz and feldspar (diamond). All lineations are subparallel, indicating very high strain.  82  Figure 2.10. Field Photographs of Kinematic Indicators at Mount Pootlass (a) (b) (c) (d)  Drag fold in metasedimentary layers indicting sinistral non-coaxial strain. Northwest to left. Field of view is —1 m wide. Drag folds in thin quartz-rich sills in foliated granite indicating sinistral, non-coaxial strain. Pen (15 cm long) points northwest. Sinistral oblique quartz stringers in boudinaged mafic sill within metasedimentary rocks. Pen (15 cm long) points to northwest. Dextral brittle ductile extensional shear band through mafic sill in foliated granite. Pen (15 cm long) points northwest.  83  Figure 2.11. Microphotographs of Rocks from Mount Pootlass: Metamorphism (a)  (b)  (c)  (d)  Greenschist metamorphic mineral assemblage in metasedimentary rock includes: chlorite (chl), plagioclase (plag), muscovite (musc) and biotite (bio). Fine-grained quartz (qtz) is dynamically recrystallized. Upper greenschist facies metamorphic mineral assemblage in metasedimentary rock includes garnet. Garnet at left side of photomicrograph has a sweeping tail of chlorite, indicating that it is pre- or syn-kinematic. Fine-grained quartz (qtz) is dynamically recrystallized. Garnet in greenschist facies metasedimentary rock with small tails of biotite. Smaller, more pristine garnet in upper right corner of microphotograph also has a small tail of chlorite, indicating garnet is pre- or syn-kinematic. Garnets have small fluid inclusions, and edges are partially resorbed. Amphibolite metamorphic mineral assemblage in metasedimentary rocks includes: hornblende (hnbl), plagioclase (plag), and epidote (ep). Note deformation twins in plagioclase, and brittle fracture of hornblende. Finegrained quartz (qtz) is dynamically recrystallized.  84  Figure 2.12. Microphotographs of Rocks from Mount Pootlass: Coaxial Strain (a)  (b)  (c) (d)  Foliated quartz-rich granite. Garnet with quartz inclusions and resorbed edges. Mica-rich seams indicate deformation by pressure solution and the presence of fluids. Deformation bands (1), and dynamic recrystallization by grain boundary migration (2) in quartz. Foliated granite. Mantled plagioclase porphyroclast (plag) with symmetric tails of dynamically recrystallized quartz (in ribbon) and biotite (bio) indicate coaxial strain. Plagioclase has deformation twins and moderate sericite alteration with no shape preferred orientation. Foliated felsic sill within metasedimentary rocks. Flattened hornblende porphyroclast with symmetrical tails of hornblende indicates coaxial strain. Very finely laminated metasedimentary rocks with conjugate kink bands indicating coaxial strain. Quartz (qtz) in silica-rich band is extemely finegrained and has undergone dynamic recrystallization.  85  Figure 2.13. Microphotographs of Rocks from Mount Pootlass: Non-coaxial Strain  (a)  Felsic sill from within foliated granite. Feldspar o-porphyroclast with asymmetrical tails of muscovite and dynamically recrystallized quartz that indicate sinistral non-coaxial strain. (b) Felsic sill from within foliated granite. Garnet o-porphyroclast with asymmetrical tails of chlorite that indicate sinistral non-coaxial strain. Groundmass is fine-grained, dynamically recrystallized quartz. (c) Felsic sill from within foliated granite. Muscovite mineral fish indicating sinistral non-coaxial strain in a groundmass of dynamically recrystallized quartz. (d) Felsic sill within foliated granite. Feldspar 6-porphyroclast with asymmetrical tails of muscovite and dynamically recrystallized quartz indicating sinistral non-coaxial strain. Static sericite replacement in feldspar is post-tectonic. (e)^Foliated chlorite cataclasite from brittle fault in foliated granite. Dextral sense of movement is indicated by quartz shear bands.  86  AN AA OVA  Ott*  VANN AVAA ON% W VAVON OVANA VANVA *WNW: ANANNA VANANW AN 11111 WOW:WAN ANNWANNAN ANANANNAVA OVVVANANNAV A ONAN. WANWANNWAN,. ,NANNANN. 4000~004010***0100****.0014~00e*, ****0*ANAMAN100000000~110 401100* O*41041100~AWOO**00000001111**104, 014010*ANANNA00~0~110*~0000111* AAP00011100~11%4000000:000011**111111 ,.. ANNVANWANVANWANAVANNANWAVANNAN, AVANANWAVAANAWANANANNWAVAANWAN. AVANNANWANNWAVAVAVANNWANNWWWAN. N A ANNWANNWAVANNANAWVANVANWANAN. NAN AVAVAWAVANNWAVANNANWANNWAVAVANWA.N , WOOWANNANNWANNWAVANWANNANWAVAAVANNA. OWANVANAVAVANWAVAVANWAVANAWANNAVAVANN, AVANAVANNANWANANAVANNANWANNWAVANNWAVANNA. ANNWANAVAANWANWANWAVANNWAVANNANWAVANNWAA AVONIAVANNANNAVANAVAVANNWANVANNAWANVANAWAN AVAA 1000AVANNWAVANWAVANWANANWWWWWWWANWAN ANNANWAVANNWAVOWAVAWAVANNWAVAVANNWAVANNVAN W V AVANWAVANNOWNWAVANANWAANWAVANNAVOANNWANN WANANWAVANNWANNWAVAAAVAN WAVANNWAVANN WAVAANA ANAVAANWAVANNAVANWAVANWAVANNANNWANNWANNWAVOA ANVANAANA WAVOWANNAVANVANANANANWANNWAVANNAVAVANNWANNWANNWAVANNANANWA AVANWANNANNANWANANAVANWAVAAVAAVANNWAVAAVAVANNWANWANAVANANAN WANWAVANNWANWAVAVAVANNAVANANWAVANNWAVAVANNAVAAVANWANANANA AVAVANNWAVANNWAVANANNAWAVANAWAVANNWAVANNWAVAANWANAVANNWA VAVAVAAAVANAVANAVAAVANWAVAVAVANWOOANWANOWAVAVANANAVAVAVW AVANNWANNVANAVANNWAVANWAVANNANWAVAVAVANNANANWAVANNWAWAVAN A AVANANWAVAAANWAVAVANNVOWAVAAAVAANANWAVANWAVAVAAVAANWAVANNVA AVAWA:AN ' 1AAVANNVANWAVANAVANWANWAVOWAVAVAVAOWAVANWA WAVANWAN NWAVAANANNANWAVAANANANWAVANNWAVANNAWANAVANAVAN WWAVAVWA^NAVANNWAVANWANWAVANWANNWAVANNWAVANNWAVANVAA ANNWAVAN.^AVANWAVANWAVAVAANWAVAANWANWAVANNAWAVANNAN, AVANANWO^VAVANWAVAAVANAVAVANWAVAVANWAVANAVANNAVAAVA A A ANNANWN^ANWAVANNWAVANNAVANAVANNANWVANAWANANAVANWA AVANNWAVANAVAANWANNWAVAVAAN WAVAANWANNWANW AV:WNW VANNWAVAVANNWANNANNANWANAVAAANWAVANNANWANNA ANNWOW WAVA 000.64.-^AVAVANNWANNWAVANNWAVAVAVANAVANNAVANAVANNANN AW*1411411•11*WWWWW*WAWINWAWANNWANWWWW*W4111* to' *'*'*V*WAW*W*W*W*V*V*WAWOW*V*W*W*Wr'*'*V*W*W*W*14 010~010000001~001000111**110000100~10**~010000000**10000100%11* 000100~4~001,100~~04****110**11400000~000100~0000***000:* 1000410000*VAANAOWNANANAMMOVIMNNANWANAAWA000000000**00**11* 00000~04~100004100AAANANOPOW001011410**AVO0111000000011141. 1000100WANAMANWOO**00**POWOMPOINANAMANWANWOWAVOA*00~0. *WWWWWW********VVVVVVVV******111******V***********1************ WANWANNWAVAVANWAVAVANNWAVANNWANWANWAVA WAVANNWANNANANN. loWo 141110 0INNAMAANANNVAVANNAPANNAA. WAVANNWANWAN VA' VONVAANVANAVAVAAAVA ^WAVANNAVANNVA WAAVAVANNWAVANNAAN ^ WANWANANNANNWANA ^ WAANANAVVVWNWOWVVN 11000.10.1110114 WWWWWWWWWWWW. ^ 1011*********** WWWWWWWWWWWW^ *1*****V******1*******1* 00111VVVVVVVV* WWWWWWWWWWWW^ 111WWWWWW. 11WWWWWWWWWW^ WWWWWWWW■ VVVVVVVVVVVVVVVVVVVIo^ 1111111111»1 VANANNAM11111111^ VVVVVVVVVVVO0 AN111111111100.^ IINN1111110000 VINAINVOIWAN41 ANNAPAN1101, PANN111411000^ ..VVVVVVVVVA, VINNANANAN' NNWINAAN1111 VANNANfto.^ 1111NAPANNW4 .0.1000•-^ 1NNWANNAPIA. VOINNWINAM, NNAINAMOVVVV■ NAINNWOVVVOr NAIMMAINAN* IINVANAINVAIN, 111111111111  Watreatt****** V***********  ■•■•■^  tatat  I  1104  NNAT: 1••■  Figure 2.12. Falls Camp Geology. Northwest of Mount Pootlass. Mapped areas shown here are separated by permanent snowpack and very steep terrain. Rock units do not appear to link up along strike, which may be due to an offsetting fault beneath the snow. Map Projection: Nad 27 Canada, UTM Zone 9. Refer to Figure 2.2b for legend. 87  Figure 2.15. Falls Camp Field Photographs (a) (b) (c) (d)  Isoclinal fold (F,) of thin felsic layer within metasedimentary strata. Pen (15 cm long) points northwest. Oblique orientation of foliation and quartz stringers (parallel to orange pencil) in mafic layer within metasedimentary package. Axial planar foliation (S I ) indicated by pen (15 cm), which points northwest. Gently undulating F, fold hinge in metasedimentary package. Pen (15 cm long) points northwest. Wide (-4 m) zone of brittle deformation, interpreted to be a dextral fault. View to northwest.  88  Figure 2.16 Falls Camp Stereonet Diagrams (equal area) (a) (b)  Poles to foliation (S I ) (dot) Intersection lineation between S o and S, (square), fold axes (F,) (triangle)  89  Figure 2.17. Microphotographs of Rocks from Falls Camp (a) (b)  (c)  (d)  Foliated granite. Quartz o-porphyroclast with tails of dynamically recrystallized quartz indicating sinistral non-coaxial strain. Foliated granite. Quartz o-porphyroclast with tails of dynamically recrystallized quartz indicating sinistral non-coaxial strain. Quartz porphyroclast exhibits chessboard subgrains. Foliated granite. Feldspar o-porphyroclast with tails of dynamically recrystallized quartz indicating sinistral non-coaxial strain. Feldspar shows strong sericite alteration which appears post-tectonic. Extensive tensile fracture of garnet in metasedimentary rock, likely due to very strong flattening.  90  Figure 2.18. Microphotographs of Rocks from Falls Camp: Deformation Microstructures in Quartz (a) (b) (c) (d)  Foliated granite. Mantled quartz porphyroclast with finger-shaped subgrains, surrounded by dynamically recrystallized quartz, and fine grained chlorite, muscovite and biotite. Foliated granite. Sigmoid of quartz with serrated grain boundaries, indicating dynamic recrystallization by grain boundary migration. Sigmoid also indicates ductile sinistral non-coaxial strain. Foliated granite. Quartz ribbon composed of fine-grained dynamically recrystallized quartz. Metasedimentary rock. Quartz grains with interfacial angles of 120°, indicate partial annealing. Carbonate cement appears to be post-tectonic.  91  \^ii \A 68 61  79 0  0  M 5,829,000+  500 m  Figure 2.19. Jump Across Geology. Located at the north end of the PHSZ, near to the Dean Channel. High strain is localized in foliated granite and metavolcanic rocks in the centre of the map area. Map Projection: Nad 27 Canada, UTM Zone 9. Refer to Figure 2.2b for legend.  92  Figure 2.20. Jump Across Field Photographs (a) (b)  Banded rhodonite layer (-40 cm wide) within metavolcanic package. Pen (15 cm long) points northwest. Sheared lapilli in metavolcanic rock indicating ductile sinistral noncoaxial strain. Pen (15 cm long) points northwest.  93  (a)^  (b)  Figure 2.21. Jump Across Stereonet Diagrams (equal area) (a) (b)  Poles to foliation (S I ) (dot) Fold axis (triangle) in upper hemisphere are F,, fold axis (triangle) in lower hemisphere are F3, intersection lineation between S o and S I (square), mineral stretching lineation in quartz (diamond)  94  Figure 2.22. Microphotographs of Rocks from Jump Across Metavolcanic rock. Tight to isoclinal F, microfolds of very thin quartz layers in metavolcanic rocks. Metavolcanic rock. Quartz o-porphyroclasts with asymmetrical tails of dynamically (b) recrystallized quartz indicating ductile sinistral non-coaxial strain. Rhodonite a-porphyroclast with asymmetrical tails of fine-grained rhodonite and (c) quartz indicating ductile sinistral non-coaxial strain. Metavolcanic rock. Domino boudins of feldspar indicating ductile sinistral (d) non-coaxial strain. (e)^Quartz-chlorite cataclasite from brittle dextral fault in foliated granite. Shear bands of fine-grained quartz and mica indicate dextral non-coaxial strain. (a)  95  Co  asD Co NN Co C  0 1.e7,  a) 2  0 0  0_ Ni  D  CO I-  2  E  a a co  00g(9179  C13  Zi79  a a CO CO  co  C  Co  4-, Co  96  Figure 2.24. Horseshoe Hill Stereonet Diagrams (equal area) (a) (b)  Poles to foliation (S 1 ) (dot) F, fold axis (triangle), intersection lineation between S o and S 1 (square)  97  Figure 2.25. Horseshoe Hill Field Photographs Boudinage of felsic sill in granite. Pen (15 cm long) points northwest. (a) Flattened mafic enclaves in foliated granite. (b) (c)^Isoclinal folds in metavolcanic rock. Pen cap (5 cm long) is parallel to axial trace. View to northwest.  98  ,  Z:44;;;'1;  "'"7"."^W'  gad  *..141105^■••,^* -410.;  M*  `• •^,  P  7-  ...g'4*"'C' - `--si:■4f  :7;  ,  *t;  -7  C  Figure 2.26. Microphotographs of Rocks from Horseshoe Hill Oblique foliation in dynamically recrystallized quartz indicating ductile dextral non-coaxial strain in foliated granite. Sinistral kinematic indicators in chlorite ultramylonite: 6-type feldspar (b) porphyroclast with asymmetrical tails of chlorite, and localized C' extensional shear bands. (c)^Metasedimentary rock. Hornblende (hnbl) displays extensive brittle fracture and is strung out along the foliation, which is also defined by fine-grained metamorphic chlorite and biotite. Weakly developed sinistral C' extensional shear bands (C') are shown with slip along chlorite and biotite.  (a)  99  85  a  U)  5,841,000 +  Figure 2.27. Mount Cloud Geology. North end of Pootass High Strain Zone near to the Dean Channel. High strain on Mount Cloud is exposed in one narrow zone in the southwest corner of the mapped area. Map Projection: Nad 27 Canada, UTM Zone 9 Refer to Figure 2.2b for legend.  100  Figure 2.28. Mount Cloud Field Photographs Isoclinal fold in metavolcanic rock. Field of view is a vertical plane —5 cm in width. Flattened mafic enclaves in hornblende monzonite. (b) Pen (15 cm long) points northwest. Drag folded quartz stringers in metavolcanic rock indicating (c)^ ductile sinistral non-coaxial strain. Pen cap (5 cm long) points southeast. (a)  101  Figure 2.29. Mount Cloud Stereonet Diagram (equal area) Poles to foliation (S 1 ) (dot)  102  Figure 2.30. Microphotographs of Rocks from Mount Cloud (a) (b)  Well-developed sinistral Riedel fabric. Slip along fine-grained clay and chlorite that define Y and R' surfaces. Sinistral offset along intragranular fracture in hornblende grain (hnbl). Metavolcanic rock. Lattice kinking in hornblende.  103  s4toki."'  •  •^-^  s  .agar-  Figure 2.31. Microphotographs of Samples Analyzed with Garnet/Biotite Geothermometry. Abbreviations: garnet (gar), biotite (bio), and chlorite (chl). (a) (b) (c) (d)  la  „tee  Sample PL7. Muscovite-chlorite-quartz felsic sill within foliated granite on eastern ridge of Mount Pootlass. Sample PL31. Chlorite-biotite schist. Greenschist facies metasedimentary rock from Mount Pootlass. Sample FC16. Mafic sill within greenschist facies metasedimentary rock from Falls Camp. Sample FC18. Felsic sill within greenschist facies metasedimentary rocks at Falls Camp.  104  Figure 2.32. Microphotographs of Samples Analyzed with Amphibole/Plagioclase Geothermometry. Abbreviations: hornblende (hnbl) and plagioclase (plag). (a) (b) (c) (d) (e) (f)  Sample PL2: mafic layer in amphibolite-grade metasedimentary rocks on Mount Pootlass. Sample PL9: mafic sill in foliated granite within high strain zone on Mount Pootlass. Sample PL28: mafic sill in amphibolite-grade metasedimentary rocks on Mount Pootlass. Sample FC l 6: mafic sill in greenschist-facies metasedimentary rocks at Falls Camp. Sample HH2: foliated hornblende-biotite granodiorite from Horseshoe Hill. Sample MC8: foliated granodiorite from high strain zone at Mount Cloud.  105  data - point error ellipses are 2it  0.021  0.019 CO  O.  0.017  0  0.015  0.013 00  0.2  0.1  0.3  207Pb/235U  data-point error symbols are 2o  130  120  110  100  I  ^  Mean = 114.2 ± 2.0 [1.8%] 95% conf. Wtd by data-pt errs only, 0 of 15 rej. MSWD = 0.53, probability = 0.92 (error bars are 2o)  90  Figure 2.33. U-Pb concordia Diagram and Weighted Averages Chart. Sample PL40 is a foliation-parallel, foliated and sinistrally sheared felsic sill within greenschist facies metasedimentary rocks on Mount Pootlass.  106  4143. 4-4 Oat  150^  0 0' 40, 1.4  130  HH1 Biotite  1•••■•0 0•Sro Beal noe.1••■■•  0/4044  tom n••■•16 •••  MC10 Biotite  SS3 Biotite 30  a  110  X  I 130  co Q .0..4 • 114 tr. net.' Jary a se) ma. - 0 38 .01.0840 66  40  1" e  2 70  50  Lem. oroe...., • mew.  . 216  00 ^ 0  Cumulative "Ai. Percent Rom 11•10 ••• NM. HR. a• me,  1110.0 gm•76^Sy. (20 M./10.1-.0e 01 5.1  .1•78 op • 72 70.84 (20,^.1.00r 01 8161  _eweeem Gem erne me,  2°^10^  eo^5(0  20^4,0  60  Cumulative "Ar Percent  Cumulative "Ar Percent O. .01•1• 1,00 ^0.4.0 6. 00400 48...  MC10 Hornblende  007 6030..  were 80.4 8.4 In 0.  ^  PL3 Biotite  200  2  •••  ^  PL3 Hornblende  leo  so  1.3.8 pa • 721220 481.64.' 120 6.0.0.0 .1.0. 01 510 145180 0 21 10010348 SIG 01. 190  op • 71 0360 /20 0.002 .084 el 6.)  120 Includ. 2008, 316)  61.0 • 34, 002.80.0 25 ,  20^40^00^80  108 20^40^00  Cumulative "Ar Percent Wm. .. an 0.1 0101. 1 14.8 120  01.8^)  0824. 82 931  ^00.7.  0 0^ 20^40^80^50  80^108  PL20 Muscovite  .41.40.0.8.61.3 00080^snr^  ^  108  Cumulative "Ar Percent  Cumulative "Ar Percent ••• .01. Dm.  .11  ^  box  *De AM f•tf. r.1.•••••••••••••• ^  PL30 Hornblende  t.•  PL31 Biotite  100  a 2  co  20  120. In01.0.4400,01 5•0 MOM • 0 NI 3.010011040 75  •0* • 63.0 00 eft', 820 1081.6320rtor 0 5x1 2031,80 0106!813. 23  100.4 65 346 Oft °Ar  e8868.0 .0 • 70.3030 02 Ma) 120 IncludIns 740.08 01.516) 5,150/0 • 1^weeete...42  0.64.0 84 7. 0111.'N  .^0.11... 20^40^00  00^10e  Cumulative "Ar Percent  20^20^40^B0  20^10^W^80  Cumulative "Ar Percent  Cumulative "Ar Percent  Figure 2.34. 40Ar/ 39Ar Step Heating Diagrams and Cooling Ages.  107  180  ^ ^  5,840,000 + 0 o^  a a  — transcurrent stress  \ \- \^,)  \<iv  ^%  \\  ^\  r). \ \ 0 k %^\ -,k) \ \L ^ ^ \.  O  CD  O  COCO CO  ± 5,770,000  compressive stress  compressive^transcurrent stress 71\stress  oblique convergence  Figure 2.35a. Strain Partitioning as a Result of Oblique Convergence. Map Projection: Nad 27 Canada, UTM Zone 9. Refer to Figure 2.35b for legend.  108  ^  N  •  •  5 C 0  a)  o C  0_  D  0 _c -o -0  • Q  O  -0 6 a) -O C =  -c5  O  a)-=  ^cn  ^g ^=  ^2  w  LLI  u_  Q 0  -  -0  •^  a) 0_ eL^a)^a) o (0^c^ _c g ro^o  u)  0^"5 N a) 0^.0  C \ I^ (i) C C C CO 2 O ..-. ^0 __7. N CO^ (7) CO 0/5 -,-•^_C^C _C 0 a.)^(I) 0)^(1)  C -t^--F, .f^.T. < . 2' VD^ a) 1 U ca)^o ow^Tcs g)  ^C ..=  ^(1) (z)  (0  CO  L  L  (  eve(  Ceeee crc'c'‹  li  I—  • (I)  (7) 0 a) o  (Co  .0  a5  co 't 0  U)  >  E  O D E  —/^CO Cs. C 75  a) ° O >  f:t • • C  73 0  C D (1.) co  Q 2, ce^  g  U) To °  •  n^u)^= o^a) -*E;  C3  -^  ^ Lo^ -^z 4oo^0)^c., < (,) co^ ,..^ = _,c 6^— c6 r a 0 ^ w (6^ — ce 0 N0^ O aice 5 _o _o^o_^0^< co o o. _c) 3^Q > o3 o -,....^Z a)^ < O .-=.^.._,^= :.=.^D^ > a) a) en m^co^:=^ re co co^ o _^co^LU TD O^c^ I- E C^o^o m U) C o^.E^< cn  Tlf^  C a) a) . 5 CIS^0 >,^D 0^0 o o_ _c) 0 0-^0_ 0...  (13 ,■_  a) c Q. C  O  w  ,  -- , ct .:E  .0) 0 a)^ o ^ (.9 o U u_^CO < 0 z 2 <^F< I-^U) W^-I Ce^> 0^< LL.^CO^ Ce y Y 0 Y > 's• Y J^_1 >- W^(>  o 2 cn 0_^ 0 < -5 0_^ ,_^U) • _c ci._ U) a)^o D^ U) 2 c^c 0 2 =< cu co^Lu -(7) o-) O =^ _ c 0 w  0  z  U.I  ^co  ^N  ^._  ^D ^W  z  ^U-I  0  i iii  ,  4^  109  •  et.%  °°%?s  w^a) a)^o ^c >^a) 5)-  w ^CD ET) 92^D CD > 0_^CT -= c ^o (..)  E^_o o O  to,49/0/  Ge,%0  ( )  1 E  O  fsi  E i.3  CO 0 ..^CD_  C 0  '4=-•  CD  -  _c  U)  o  c c  o cf)  ci) m _c 0_ CO  (1)  to  0) oc occ”  m a) Ni a) co F.- _c (/) O  V),  cn  0 -0  -0  a) a) -0 a) as (13 al  E0 E EE  92 0  -  cu °  cT3 0 0 ^0  _1  0 (/) w C•—. 0 W W -  ,_a) )  U) CD  cn  92 .> (7) 2 (1) C.) 0_ a)  co  0 E c E a)^a)  c.O (13 O  O nj 0 m  U)  CU (5 - LL/  LLm  110  ^ ^  c.i)  ^a)  ^.  ^0  ^a) ^^Q  ^1  2  O 0)  0  7 12 --  1_/) Cc w 0 w .2 0  E ("5 4=. E 8 > U) 0o co o c O N Ni co 0) I 2 DO_ 0_ W W x  -  t >9  cfi cL-t1 a) ---, 7) -c^a) w u)^ O0 45  E 2 (1)(,) .-3 .—^ "rn -t -cTs^0)a) >, o _c c a_ o  u)^  N -Ti c -0 1_5 2^2 0) E. —I— E. a) ai^D ai. -ci c  0)^-0  (  O -c -'-i  (-)^0  a) 6  (1) Tx1 T2 C^C ^CD 0) C D C.)f6 0 4=^0^CU  _c  _a a) -(7)^ p  6 cn El^CV N.-  D  >, o :^ c E co u-) m 7 2;- (7)^Z N  ;:(-- -0 a)^E c -c o • cu^.÷,  I  f'--^>,^0 0) ? -6 -CD^CD 0  92^2 Ct  2 g -2 0 'a5 a4a3 ° 0^Cl.(,,,,(D  73a)^ff  ^N  .c°  ^C  ^"u:  111  5,840,000 + 0 0  0 20 km •  •  PHSZ 'of  o  G  Ldp  °  negative flower structure  + 5,778,000 Figure 2.38. The PHSZ and Talchako Fault as a System of Sinistral Extensional Step-Overs. Map Projection: Nad 27, UTM Zone 9. Refer to Figure 2.5b for legend.  Schematic Cross Section see above map for cross section location  !modified from: Twiss and Moores, 1992  112  CHAPTER THREE  3.0 SUGGESTIONS FOR FUTURE WORK My work has characterized the PHSZ with regards to its geometry, timing, kinematics, pressure, and temperature of deformation. Interpretations were also made to place the PHSZ within a regional tectonic framework. In spite of this research, outstanding questions remain. The following are recommendations for further research within the PHSZ and surrounding area that would further constrain the deformation history of the PHSZ and, in particular would place better constraints on the kinematic link between the PHSZ and other structures in the Bella Coola region.  3.0.1 Constraints on the Geometry of the PHSZ The PHSZ is characterized by rugged, steep to gently rounded glaciated mountains of the British Columbia Coast Mountain chain and is accessed only by helicopter. Permanent snow pack covers much of the PHSZ and an especially heavy snowfall during the winter of 2006-2007 limited accessible outcrop exposures. For these reasons, the extent of the PHSZ is not well defined and this corridor of deformation may continue farther to the north and to the south than what was mapped during this study. Further exploration and detailed mapping is needed to delineate the PHSZ with more certainty.  113  3.0.2 Constraints on Pressure and Temperature of Deformation Temperature and pressure data, obtained from garnet/biotite and amphibole/plagioclase geothermometry and microstructural analysis, suggests that deformation throughout the PHSZ occurred at temperatures of 537 to 731°C, and at midcrustal depths of —23 km. In order to further refine these ranges in temperature and pressure of deformation additional samples could be collected and analyzed. Such research may explain variations in deformation style along strike in the PHSZ. This process is hampered by a paucity of co-existing garnet and biotite and by sericitization and alteration of otherwise suitable rock specimens.  3.0.3 Constraints on Kinematics To further support the kinematic analysis of the PHSZ presented in this thesis, an extensive EBSD analysis of dynamically recrystallized quartz would be suitable to identify any crystallographic preferred orientations that may be useful as kinematic indicators. Crystallographic preferred orientation patterns have been used as a tool of deformation process analysis for almost a century (Prior et al., 1999). Under non-coaxial progressive plane strain deformation, the c-axis of quartz grains commonly form a predicable pattern that can be used to determine the kinematic sense of deformation (Passchier and Trouw, 2005). Under these conditions a crystallographic preferred orientation is expected to strengthen with increasing strain (Prior et al., 1999).  114  3.0.4 Constraints on Tectonic Significance Deformation recorded in the PHSZ and in the Talchako fault indicate that sinistral ductile transpression persisted in the Bella Coola area through the Late Cretaceous. Additional structures that support this hypothesis remain unidentified in the Bella Coola region. Further detailed mapping to the west and to the east of the PHSZ with a focus on the identification and characterization of high strain zones may identify additional structures that are temporally and/or kinematically related to the PHSZ and/or the Talchako fault.  115  REFERENCES Andronicos, C.L., Chardon, D.H., and Hollister, L.S., 2003. Strain partitioning in an obliquely convergent orogen, plutonism, and synorogenic collapse: Coast Mountains Batholith, British Columbia, Canada, Tectonics, v. 22, n. 2, 24 p. 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Active foundering of a continental root beneath the southern Sierra Nevada in California, Nature, v. 431, p. 41-46.  122  APPENDIX I^(ON CD) Petrographical Descriptions, Microphotographs, and Microphotograph Log Note: In all microphotographs, the horizontal axis is aligned with foliation.  123  APPENDIX II Garnet/Biotite and Amphibole/Plagioclase Geothermometry: Methodology and Data  Garnet/Biotite Methodology  Four samples with igneous or metamorphic biotite and garnet occurring in contact with one another were selected for biotite/garnet geothermometry. Grain rims of biotite/garnet pairs were analyzed in a microprobe for oxide % weights of Si, Ti, Al, Fe, Mn, Mg, Ca and Na. Microprobe data was used according to the method described by Ferry and Spear (1978), which assumes an equilibrium state for each mineral pair and determines temperatures of crystallization based on the Fe/Mg exchange ratio of biotite and garnet. Garnet/biotite sample descriptions are provided in Table II-A, data are provided in Table II-B, and calculations in Table II-C.  Amphibole/Plagioclase Methodology  Samples with igneous or metamorphic hornblende and plagioclase interpreted to be in equilibrium, were selected to determine the pressure and temperature of metamorphism using the Holland and Blundy method (Holland and Blundy, 1994). Rims of amphibole and plagioclase pairs that occur in contact with each other were analyzed in a microprobe for oxide % weights of Si, Ti, Al, Cr, Fe, Mg, Mn, Ca, Na, K and Si, Al, Fe, Mg, Mn, Ca, Na, K, respectively. Calculations were performed with "hbplag", a public domain application for calculating hornblende-plagioclase geothermometry, based on the thermometers of Holland and Blundy (1994). An equilibrium state is assumed for each mineral pair and temperatures of crystallization are calculated from the composition of  124  amphibole and the albite content of plagioclase. Amphibole/plagioclase sample descriptions are provided in Table II-A, data are provided in Table II-D, and calculations in Table II-E.  125  REFERENCES Ferry, J.M., and Spear, F.S., 1978. Experimental Calibration of the Partitioning of Fe and Mg Between Biotite and Garnet, Contributions to Mineralogy and Petrology, v. 66, p. 113-117. Holland, T., and Blundy, J., 1994. Non-ideal interactions in calcic amphiboles and their bearing on amphibole-plagioclase thermometry, Contributions to Mineralogy and Petrology, v. 116, p. 433-447.  126  Table II-A  Geothermometry Sample Locations and Descriptions  Sample UTM East UTM North  PL2  649968  5812767  PL7  652079  5812593  PL9  652058  5812669  PL28  649951  5812765  PL31  649848  5812779  FC16  645521  5817761  FC18  645567  5817768  HH2  643188  5833888  MC8  643203  5840392  Sample Description Mafic sheeted intrusion from within high strain zone on Mount Pootlass. Muscovite-chlorite-quartz mylonite from high strain zone on Mount Pootlass. Mafic sheeted intrusion from within high strain zone on Mount Pootlass. Amphibolite sheeted intrusion in metasedimentary rocks within high strain zone on Mount Pootlass. Chlorite-biotite schist, metasedimentary rock from within high strain zone on Mount Pootlass. Hornblende-quartz schist, metasedimentary rock from within high strain zone at Falls Camp. Quartz mylonite. Sheeted intrusion in metasedimentary rocks within high strain zone at Falls Camp. Foliated hornblende-biotite granodiorite from Horseshoe Hill. Finely laminated hornblendechlorite schist from high strain zone on Mount Cloud.  Method  amph/plag  bio/gar  amph/plag  amph/plag  bio/gar bio/gar and amph/plag  bio/gar  amph/plag  amph/plag  All coordinates NAD 27 for Canada, UTM Zone 9 amph/plag: amphibole plagioclase geothermometer after Holland and Blundy (1994) bio/gar: biotite garnet geothermometer after Ferry and Spear (1978)  127  Table 11-B  Garnet/Biotite Microprobe Data  GARNET Sample  FC18-5  FC18-3  FC18-6  FC18-7  FC18-8  FC18-9  F18-10  NA2O MGO AL203 S102 CAO 1102 CR203 MNO FEO  0.05 0.98 21.14 36.22 0.88 0.02 0.00 6.57 34.61  0.09 0.91 20.86 36.13 1.02 0.03 0.04 6.53 34.89  0.04 1.06 21.12 35.96 0.52 0.01 0.06 6.37 34.73  0.03 0.87 21.07 35.90 0.79 0.02 0.00 6.60 34.27  0.01 0.93 20.87 36.13 1.01 0.01 0.02 7.55 33.93  0.03 0.95 21.22 36.23 0.85 0.01 0.00 7.28 34.19  0.00 1.09 21.22 36.04 1.00 0.04 0.00 6.35 34.47  0.02 1.02 20.79 35.06 1.06 0.00 0.00 6.36 35.14  0.04 1.08 21.37 35.51 0.78 0.00 0.00 6.78 34.53  0.03 0.98 20.97 35.96 1.21 0.01 0.00 6.29 34.46  TOTAL  100.47  100.50  99.87  99.55  100.46  100.76  100.21  99.45  100.09  99.91  NA+ MG2+ AL3+ S14+ CA2+ T14+ CR3+ MN2+ FE2+  0.008 0.119 2.037 2.961 0.077 0.001 0.000 0.455 2.366  0.014 0.111 2.014 2.960 0.090 0.002 0.003 0.453 2.390  0.006 0.130 2.046 2.956 0.046 0.001 0.004 0.444 2.388  0.005 0.107 2.048 2.961 0.070 0.001 0.000 0.461 2.364  0.002 0.114 2.016 2.961 0.089 0.001 0.001 0.524 2.325  0.005 0.116 2.040 2.955 0.074 0.001 0.000 0.503 2.332  0.000 0.133 2.048 2.951 0.088 0.002 0.000 0.440 2.360  0.003 0.126 2.037 2.915 0.094 0.000 0.000 0.448 2.443  0.006 0.132 2.071 2.921 0.069 0.000 0.000 0.472 2.375  0.005 0.120 2.032 2.957 0.107 0.001 0.000 0.438 2.370  8.024 12.000  8.037 12.000  8.021 12.000  8.016 12.000  8.031 12.000  8.026 12.000  8.023 12.000  8.068 12.000  8.047 12.000  8.029 12.000  Cation Sum Anion Sum Sample _ 1`) 00  FC18-1^FC18-2^FC18-4  NA2O MGO  F18-11 0.02 1.09  F18-12 0.00 0.99  F18-13 0.01 1.00  F18-14 0.01 1.05  F18-15 0.03 0.94  F18-16 0.02 1.08  F16-17 0.03 1.08  F18-18 0.04 0.92  F18-19 0.00 1.03  F18-20 0.04 0.97  Table 11-B  Garnet/Biotite Microprobe Data  AL203 S102 CAO 1102 CR203 MNO FEO  21.18 35.81 0.93 0.01 0.00 7.22 34.08  21.05 36.02 1.18 0.00 0.00 6.51 34.30  20.90 35.99 0.98 0.01 0.00 7.62 33.32  20.49 35.73 1.04 0.00 0.00 7.50 33.72  20.72 35.93 1.01 0.02 0.00 7.89 33.42  20.63 35.86 1.06 0.02 0.02 7.13 34.34  21.09 35.47 0.58 0.00 0.01 6.42 34.22  20.90 35.77 0.89 0.02 0.02 6.44 34.92  21.26 35.81 0.65 0.01 0.00 6.72 34.52  20.47 36.06 1.05 0.00 0.00 6.75 35.03  TOTAL  100.34  100.05  99.83  99.54  99.96  100.16  98.90  99.92  100.00  100.37  NA+ MG2+ AL3+ S14+ CA2+ T14+ CR3+ MN2+ FE2+  0.003 0.133 2.047 2.937 0.082 0.001 0.000 0.501 2.337  0.000 0.121 2.036 2.957 0.104 0.000 0.000 0.453 2.355  0.002 0.123 2.027 2.962 0.086 0.001 0.000 0.531 2.293  0.002 0.130 2.000 2.959 0.092 0.000 0.000 0.526 2.335  0.005 0.115 2.012 2.960 0.089 0.001 0.000 0.551 2.302  0.003 0.133 2.002 2.952 0.093 0.001 0.001 0.497 2.364  0.005 0.134 2.063 2.945 0.052 0.000 0.001 0.451 2.376  0.006 0.113 2.031 2.949 0.079 0.001 0.001 0.450 2.407  0.000 0.126 2.059 2.943 0.057 0.001 0.000 0.468 2.373  0.006 0.119 1.984 2.965 0.093 0.000 0.000 0.470 2.409  8.041 12.000  8.025 12.000  8.025 12.000  8.043 12.000  8.035 12.000  8.047 12.000  8.026 12.000  8.037 12.000  8.027 12.000  8.046 12.000  Cation Sum Anion Sum  Sample NA2O MGO AL203 S102 CAO 1102 CR203 MNO " c::)^FEO  F18-21 0.08 1.03 20.98 35.62 0.85 0.02 0.00 6.31 34.86  F18-22 0.08 0.96 20.91 35.89 0.73 0.02 0.01 6.59 34.76  F18-23 0.05 1.37 20.59 36.01 1.00 0.03 0.00 19.49 20.95  F18-24 0.03 1.35 20.67 36.30 0.83 0.02 0.00 18.86 21.34  F18-25 0.15 1.22 20.04 35.81 1.21 0.16 0.01 19.74 21.11  F18-26 0.03 1.20 20.33 36.17 1.43 0.03 0.00 19.59 21.22  F18-27 0.02 1.27 20.60 35.98 1.52 0.03 0.01 19.28 21.32  F18-28 0.04 1.23 19.93 36.04 1.51 0.11 0.00 19.17 21.69  F18-29 0.05 1.19 20.82 36.11 1.41 0.03 0.06 20.03 20.54  F18-30 0.05 1.23 20.76 35.73 1.32 0.06 0.00 19.71 20.54  Table 11-B TOTAL  99.75  99.95  99.49  99.40  99.45  100.00  100.03  99.72  100.24  99.40  NA+ MG2+ AL3+ S14+ CA2+ T14+ CR3+ MN2+ FE2+  0.013 0.127 2.041 2.940 0.075 0.001 0.000 0.441 2.406  0.013 0.118 2.029 2.955 0.064 0.001 0.001 0.460 2.394  0.008 0.168 1.999 2.967 0.088 0.002 0.000 1.360 1.443  0.005 0.165 2.003 2.985 0.073 0.001 0.000 1.314 1.468  0.024 0.151 1.955 2.965 0.107 0.010 0.001 1.384 1.462  0.005 0.147 1.969 2.973 0.126 0.002 0.000 1.364 1.458  0.003 0.155 1.994 2.955 0.134 0.002 0.001 1.341 1.464  0.006 0.151 1.939 2.976 0.134 0.007 0.000 1.341 1.498  0.008 0.145 2.008 2.955 0.124 0.002 0.004 1.389 1.406  0.008 0.151 2.019 2.948 0.117 0.004 0.000 1.378 1.417  8.045 12.000  8.035 12.000  8.036 12.000  8.014 12.000  8.059 12.000  8.043 12.000  8.048 12.000  8.051 12.000  8.041 12.000  8.042 12.000  Cation Sum Anion Sum  Sample  `8'  Garnet/Biotite Microprobe Data  F18-31  F18-32  F18-33  F183-4  F18-35  F18-36  F18-37  F18-38  F18-39  F18-40  NA2O MGO AL203 S102 CAO TIO2 CR203 MNO FEO  0.00 1.24 20.71 36.39 1.39 0.04 0.00 19.99 20.48  0.01 1.31 20.59 36.32 1.45 0.02 0.00 19.77 20.65  0.01 0.85 20.82 35.55 1.51 0.02 0.05 21.48 19.34  0.00 0.99 20.91 35.80 1.24 0.08 0.00 20.76 19.82  0.02 1.05 20.79 35.50 1.10 0.20 0.03 20.75 20.12  0.00 1.06 20.94 36.05 0.95 0.04 0.02 20.42 19.86  0.05 1.09 19.92 35.96 1.25 0.12 0.00 20.86 20.32  0.05 1.15 20.68 35.92 1.13 0.17 0.06 20.56 19.98  0.00 1.27 20.39 35.93 1.41 0.10 0.00 20.05 21.03  0.00 1.11 20.67 36.43 1.59 0.00 0.02 21.07 19.30  TOTAL  100.24  100.12  99.63  99.60  99.56  99.34  99.57  99.70  100.18  100.19  NA+ MG2+ AL3+  0.000 0.151 1.995  0.002 0.160 1.986  0.002 0.105 2.027  0.000 0.122 2.030  0.003 0.129 2.024  0.000 0.130 2.033  0.008 0.134 1.943  0.008 0.141 2.006  0.000 0.156 1.975  0.000 0.135 1.992  Table 11-B S14+ CA2+ T14+ CR3+ MN2+ FE2+ Cation Sum Anion Sum  Sample  Garnet/Biotite Microprobe Data 2.974 0.122 0.002 0.000 1.384 1.400  2.973 0.127 0.001 0.000 1.371 1.414  2.937 0.134 0.001 0.003 1.503 1.336  2.950 0.109 0.005 0.000 1.449 1.366  2.933 0.097 0.012 0.002 1.452 1.390  2.969 0.084 0.002 0.001 1.424 1.368  2.976 0.111 0.007 0.000 1.462 1.406  2.956 0.100 0.011 0.004 1.433 1.375  2.953 0.124 0.006 0.000 1.396 1.445  2.979 0.139 0.000 0.001 1.459 1.320  8.027 12.000  8.033 12.000  8.048 12.000  8.030 12.000  8.043 12.000  8.012 12.000  8.049 12.000  8.033 12.000  8.054 12.000  8.025 12.000  F18-41  F1-42  F18-43  F18-44  F18-45  F18-46  PL31-1  PL31-2  PL31-3  PL31-4  NA2O MGO AL203 S102 CAO 1102 CR203 MNO FEO  0.01 1.10 21.00 35.99 0.92 0.02 0.00 21.23 19.22  0.03 1.00 21.13 35.88 1.37 0.08 0.01 21.26 18.91  0.00 1.03 20.10 35.43 1.28 0.10 0.00 21.49 19.99  0.06 1.21 20.41 35.77 1.09 0.08 0.00 20.39 20.36  0.06 1.17 20.75 35.83 1.51 0.00 0.00 20.03 20.03  0.03 1.24 20.66 36.12 1.66 0.03 0.02 19.48 20.16  0.05 1.76 21.30 36.55 3.83 0.00 0.05 5.41 31.07  0.07 2.08 21.41 35.62 3.31 0.02 0.02 4.83 31.02  0.05 1.91 21.20 36.48 3.56 0.00 0.04 4.90 31.08  0.06 1.57 21.60 35.80 3.62 0.03 0.02 5.96 30.18  TOTAL  99.49  99.67  99.42  99.37  99.38  99.40  100.02  98.38  99.22  98.84  NA+ MG2+ AL3+ S14+ CA2+ 114+ CR3+ MN2+ FE2+  0.002 0.135 2.037 2.962 0.081 0.001 0.000 1.480 1.323  0.005 0.122 2.046 2.948 0.121 0.005 0.001 1.479 1.299  0.000 0.128 1.969 2.945 0.114 0.006 0.000 1.513 1.390  0.010 0.149 1.990 2.959 0.097 0.005 0.000 1.429 1.408  0.010 0.144 2.017 2.955 0.133 0.000 0.000 1.399 1.382  0.005 0.152 2.003 2.972 0.146 0.002 0.001 1.358 1.387  0.008 0.213 2.033 2.960 0.332 0.000 0.003 0.371 2.105  0.011 0.255 2.075 2.930 0.292 0.001 0.001 0.336 2.134  0.008 0.232 2.035 2.971 0.311 0.000 0.003 0.338 2.117  0.010 0.192 2.086 2.934 0.318 0.002 0.001 0.414 2.069  ^  Table 11-B  Garnet/Biotite Microprobe Data  8.064 ^8.020^8.026^ Cation Sum 12.000^12.000^12.000 Anion Sum  Sample  8.046 12.000 PL31-8  PL31-5^PL31-6^PL31-7  8.041 12.000  8.026 12.000 P31-10  PL31-9  8.025 12.000  8.036 12.000 P31-12  P31-11  8.014 12.000 P31-13  8.025 12.000 P31-14  NA2O MGO AL203 S102 CAO TIO2 CR203 MNO FEO  0.04 2.01 21.67 36.52 3.68 0.00 0.03 5.07 30.92  0.04 1.98 21.61 35.97 3.07 0.01 0.02 5.12 31.57  0.06 2.25 21.53 36.74 2.90 0.00 0.00 4.75 31.65  0.07 1.93 21.51 35.51 3.50 0.01 0.02 5.17 31.23  0.05 2.05 21.37 36.68 3.53 0.02 0.03 4.99 31.52  0.04 1.84 21.71 35.67 3.65 0.01 0.00 5.24 30.86  0.05 1.92 21.46 36.92 3.36 0.00 0.00 5.19 31.29  0.05 2.14 21.41 36.02 3.01 0.01 0.00 4.94 31.99  0.05 2.18 21.52 36.59 3.05 0.02 0.00 4.76 31.51  0.04 1.97 21.44 35.94 2.34 0.01 0.01 6.32 31.59  TOTAL  99.94  99.39  99.88  98.95  100.24  99.02  100.19  99.57  99.68  99.66  NA+ MG2+ AL3+ S14+ CA2+ T14+ CR3+ MN2+ FE2+  0.006 0.242 2.064 2.951 0.319 0.000 0.002 0.347 2.089  0.006 0.241 2.076 2.932 0.268 0.001 0.001 0.354 2.152  0.009 0.271 2.050 2.968 0.251 0.000 0.000 0.325 2.138  0.011 0.236 2.080 2.913 0.308 0.001 0.001 0.359 2.143  0.008 0.247 2.033 2.961 0.305 0.001 0.002 0.341 2.128  0.006 0.224 2.093 2.918 0.320 0.001 0.000 0.363 2.111  0.008 0.231 2.039 2.976 0.290 0.000 0.000 0.354 2.110  0.008 0.260 2.056 2.934 0.263 0.001 0.000 0.341 2.179  0.008 0.263 2.054 2.963 0.265 0.001 0.000 0.326 2.134  0.006 0.240 2.062 2.933 0.205 0.001 0.001 0.437 2.156  8.020 12.000  8.031 12.000  8.012 12.000  8.051 12.000  8.025 12.000  8.038 12.000  8.008 12.000  8.041 12.000  8.013 12.000  8.039 12.000  Cation Sum Anion Sum  Sample NA2O MGO  P31-15 0.11 2.21  P31-16 0.00 1.93  P31-17 0.03 2.04  P31-18 0.03 1.79  P31-19 0.02 1.69  P31-20 0.03 1.96  P31-21 0.03 1.87  P31-22 0.02 2.00  P31-23 0.02 1.87  P31-24 0.01 2.03  Table 11-B AL203 S102 CAO TIO2 CR203 MNO FEO  Microprobe Data 21.58 21.54 36.85 35.76 3.57 3.29 0.00 0.00 0.01 0.03 5.28 5.40 31.61 31.42  21.38 36.34 4.27 0.03 0.00 5.23 30.29  21.42 36.34 4.06 0.00 0.01 5.57 29.92  21.56 35.85 3.29 0.00 0.02 5.28 30.63  21.49 36.95 4.09 0.00 0.00 5.31 30.89  21.43 36.09 2.92 0.01 0.04 5.37 31.47  21.38 36.88 3.95 0.01 0.00 5.12 30.64  21.47 36.01 3.46 0.00 0.00 5.29 30.99  TOTAL  99.62  99.60  100.74  99.36  99.03  98.62  100.63  99.35  99.87  99.26  NA+ MG2+ AL3+ S14+ CA2+ T14+ CR3+ MN2+ FE2+  0.017 0.267 2.047 2.967 0.217 0.000 0.001 0.418 2.084  0.000 0.235 2.075 2.917 0.288 0.000 0.002 0.373 2.156  0.005 0.244 2.039 2.959 0.307 0.000 0.001 0.359 2.110  0.005 0.217 2.049 2.955 0.372 0.002 0.000 0.360 2.060  0.003 0.205 2.058 2.963 0.355 0.000 0.001 0.385 2.040  0.005 0.239 2.083 2.938 0.289 0.000 0.001 0.367 2.100  0.005 0.224 2.034 2.967 0.352 0.000 0.000 0.361 2.075  0.003 0.243 2.060 2.944 0.255 0.001 0.003 0.371 2.147  0.003 0.225 2.035 2.979 0.342 0.001 0.000 0.350 2.070  0.002 0.247 2.064 2.937 0.302 0.000 0.000 0.365 2.114  8.018 12.000  8.045 12.000  8.024 12.000  8.021 12.000  8.009 12.000  8.022 12.000  8.018 12.000  8.026 12.000  8.005 12.000  8.032 12.000  Cation Sum Anion Sum Sample  _, ,„ `'-'  Garnet/Biotite 21.41 36.58 2.50 0.00 0.01 6.08 30.72  NA2O MGO AL203 S102 CAO TIO2 CR203 MNO FEO  P31-25 0.04 1.81 21.33 36.84 4.06 0.00 0.01 5.30 30.16  P31-26 0.05 2.04 21.60 35.88 4.43 0.01 0.05 4.94 30.20  FC16-1 0.03 1.64 21.40 36.84 6.75 0.04 0.05 7.38 26.08  FC16-2 0.03 1.58 21.44 36.33 8.07 0.11 0.01 6.96 25.33  FC16-3 0.08 1.71 21.37 36.95 7.30 0.03 0.00 7.44 24.99  FC16-4 0.02 1.63 21.43 36.34 6.86 0.03 0.02 9.22 23.68  FC16-5 0.02 1.64 21.44 36.89 6.79 0.08 0.04 9.35 23.78  FC16-6 0.01 1.50 21.62 36.05 7.27 0.01 0.00 9.41 24.10  FC16-7 0.07 1.69 21.34 37.00 5.03 0.04 0.00 5.00 30.16  FC16-8 0.07 1.85 21.33 36.03 4.70 0.00 0.00 5.01 30.14  Table II-B Garnet/Biotite Microprobe Data TOTAL^99.55^99.20^100.21^99.86^99.87^99.23^100.03^99.97^100.33^99.13  NA+^0.006^0.008^0.005^0.005^0.012^0.003^0.003^0.002^0.011^0.011 MG2+^0.218^0.248^0.196^0.190^0.205^0.197^0.196^0.181^0.203^0.225 AL3+^2.036^2.074^2.026^2.037^2.023^2.047^2.030^2.059^2.023^2.051 S14+^2.983^2.923^2.959^2.929^2.968^2.946^2.963^2.913^2.975^2.940 CA2+^0.352^0.387^0.581^0.697^0.628^0.596^0.584^0.629^0.433^0.411 T14+^0.000^0.001^0.002^0.007^0.002^0.002^0.005^0.001^0.002^0.000 CR3+^0.001^0.003^0.003^0.001^0.000^0.001^0.003^0.000^0.000^0.000 MN2+^0.363^0.341^0.502^0.475^0.506^0.633^0.636^0.644^0.341^0.346 FE2+^2.042^2.058^1.752^1.708^1.679^1.605^1.597^1.629^2.028^2.056 Cation Sum^8.002^8.042^8.026^8.048^8.024^8.030^8.017^8.057^8.016^8.040 Anion Sum^12.000^12.000^12.000^12.000^12.000^12.000^12.000^12.000^12.000^12.000  Sample^FC16-9^F16-10^F16-11^F16-12^F16-13^F16-14^F16-15^F16-16^F16-17^F16-18 NA2O^0.04^0.03^0.05^0.02^0.03^0.04^0.03^0.05^0.02^0.05 MGO^1.71^1.66^1.64^1.63^1.70^1.58^1.58^1.77^1.56^1.64 AL2O3^21.53^21.35^21.37^21.57^21.41^20.48^21.62^21.36^21.55^21.43 S102^36.39^36.07^36.61^36.44^37.11^39.23^36.72^36.01^37.03^36.04 CAO^4.81^4.38^4.81^5.59^4.73^4.37^4.85^3.84^5.72^4.69 TIO2^0.03^0.04^0.02^0.03^0.02^0.01^0.02^0.04^0.01^0.00 CR203^0.05^0.00^0.02^0.01^0.00^0.02^0.00^0.00^0.02^0.00 MNO^5.32^5.42^5.30^5.13^5.11^5.16^5.49^5.79^5.48^5.80 FEO^29.70^30.27^29.91^29.63^30.22^28.33^29.72^30.22^29.32^30.22 TOTAL^99.58^99.22^99.73^100.05^100.33^99.22^100.03^99.08^100.71^99.87  NA+^0.006^0.005^0.008^0.003^0.005^0.006^0.005^0.008^0.003^0.008 _ MG2+^0.207^0.202^0.198^0.196^0.204^0.189^0.190^0.216^0.186^0.199 2.057^2.053^2.039^2.052^2.028^1.933^2.055^2.058^2.034^2.052 `-'-' AL3+ -1=.^  Table 11-B 514+ CA2+ T14+ CR3+ MN2+ FE2+ Cation Sum Anion Sum  Sample  w ki,  Garnet/Biotite Microprobe Data 2.950 0.418 0.002 0.003 0.365 2.013  2.944 0.383 0.002 0.000 0.375 2.066  2.964 0.417 0.001 0.001 0.363 2.025  2.942 0.484 0.002 0.001 0.351 2.001  2.982 0.407 0.001 0.000 0.348 2.031  3.142 0.375 0.001 0.001 0.350 1.897  2.962 0.419 0.001 0.000 0.375 2.005  2.943 0.336 0.002 0.000 0.401 2.066  2.966 0.491 0.001 0.001 0.372 1.964  2.929 0.408 0.000 0.000 0.399 2.054  8.021 12.000  8.030 12.000  8.018 12.000  8.031 12.000  8.005 12.000  7.894 12.000  8.012 12.000  8.030 12.000  8.018 12.000  8.049 12.000  F16-19  NA2O MGO AL203 S102 CAO T102 CR203 MNO FEO  0.05 1.62 21.73 36.62 5.36 0.01 0.00 5.21 29.75  TOTAL  100.35  NA+ MG2+ AL3+ S14+ CA2+ T14+ CR3+ MN2+ FE2+  0.008 0.194 2.060 2.946 0.462 0.001 0.000 0.355 2.001  Table 11-B Cation Sum Anion Sum  Garnet/Biotite Microprobe Data 8.027 12.000  BIOTITE  Sample  _  FC18-1  FC18-2  FC18-5  FC18-7  FC18-8  FC18-9  F18-11  F18-14  F18-15  F18-16  F NA2O MGO AL203 S102 K20 CAO TIO2 CR203 MNO FEO H2O * 0=F  0.06 0.12 3.78 18.26 32.65 6.97 0.20 1.60 0.04 0.28 29.46 3.66 -0.03  0.04 0.17 4.45 18.80 27.52 0.28 0.47 0.78 0.00 0.48 36.78 3.47 -0.02  0.04 0.48 4.44 18.54 29.09 2.20 0.22 0.86 0.00 0.33 32.63 3.48 -0.02  0.00 0.16 3.67 18.26 34.07 9.34 0.07 1.71 0.00 0.37 28.95 3.79 0.00  0.46 0.23 3.35 18.40 31.30 0.53 10.24 0.41 0.01 0.48 26.98 3.47 -0.19  0.07 0.07 5.04 20.35 25.47 0.08 0.01 0.18 0.04 0.72 39.33 3.47 -0.03  0.00 0.06 3.89 17.91 32.65 7.39 0.18 1.61 0.00 0.44 29.52 3.69 0.00  0.03 0.06 3.75 18.41 33.83 8.79 0.11 1.53 0.00 0.33 29.09 3.76 -0.01  0.00 0.25 4.97 18.85 25.27 0.28 0.07 0.27 0.00 0.55 38.75 3.41 0.00  0.04 0.29 4.60 17.15 24.93 0.51 0.09 0.99 0.00 0.45 36.87 3.26 -0.02  TOTAL  97.05  93.23  92.30  100.39  95.66  94.80  97.34  99.68  92.67  89.17  FNA+ MG2+ AL3+ S14+ K+ CA2+ T14+ CR3+  0.015 0.019 0.458 1.749 2.654 0.723 0.017 0.098 0.003  0.011 0.028 0.570 1.903 2.363 0.031 0.043 0.050 0.000  0.011 0.080 0.566 1.870 2.489 0.240 0.020 0.055 0.000  0.000 0.025 0.432 1.701 2.693 0.942 0.006 0.102 0.000  0.118 0.036 0.406 1.764 2.546 0.055 0.892 0.025 0.001  0.019 0.012 0.644 2.055 2.182 0.009 0.001 0.012 0.003  0.000 0.009 0.472 1.717 2.656 0.767 0.016 0.099 0.000  0.008 0.009 0.444 1.723 2.687 0.891 0.009 0.091 0.000  0.000 0.043 0.652 1.954 2.223 0.031 0.007 0.018 0.000  0.012 0.051 0.626 1.846 2.277 0.059 0.009 0.068 0.000  Table II-B MN2+ FE2+ H+ 02Cation Sum Anion Sum Sample  -  Garnet/Biotite Microprobe Data 0.024 0.035 0.019 2.641 2.335 2.003 1.989 1.989 1.985 11.989 11.989 11.985  0.025 1.914 2.000 12.000  0.033 1.835 1.882 11.882  0.052 2.818 1.981 11.981  0.030 2.008 2.000 12.000  0.022 1.932 1.992 11.992  0.041 2.851 2.000 12.000  0.035 2.816 1.988 11.988  7.680 12.000  7.838 12.000  7.593 12.000  7.787 12.000  7.775 12.000  7.810 12.000  7.819 12.000  7.788 12.000  7.743 12.000 F18-18  7.665 12.000 F18-19  F18-24  F18-27  F18-30  F18-31  F18-32  F18-33  F18-36  F18-37  F NA2O MGO AL203 S102 K2O CAO TIO2 CR203 MNO FEO H2O * 0=F  0.00 0.06 4.32 17.35 27.51 1.72 0.37 1.21 0.00 0.45 35.56 3.42 0.00  0.03 0.11 4.01 17.79 29.53 4.21 0.44 1.44 0.00 0.30 31.96 3.50 -0.01  0.20 0.05 7.69 16.32 34.57 8.79 0.12 2.16 0.03 0.86 23.91 3.70 -0.08  0.39 0.09 8.84 16.62 35.38 9.39 0.08 2.68 0.00 0.78 21.90 3.70 -0.16  0.30 0.05 10.35 17.80 29.25 1.22 1.26 0.55 0.00 1.03 25.48 3.42 -0.13  0.54 0.08 10.38 17.95 35.32 5.45 0.34 0.69 0.00 0.99 21.68 3.61 -0.23  0.31 0.09 9.96 18.14 32.94 4.88 0.45 1.07 0.03 0.91 23.77 3.64 -0.13  0.39 1.79 5.89 16.64 41.75 4.76 0.85 1.33 0.02 0.33 14.54 3.68 -0.16  0.42 0.10 8.64 17.22 35.85 9.39 0.10 2.43 0.00 0.58 21.65 3.71 -0.18  0.23 0.09 8.65 16.98 35.41 9.33 0.08 1.09 0.02 0.84 23.10 3.75 -0.10  TOTAL  91.97  93.31  98.32  99.68  90.58  96.80  96.06  91.81  99.91  99.47  FNA+ MG2+ AL3+ S14+ K+ CA2+ T14+  0.000 0.010 0.564 1.790 2.409 0.192 0.035 0.080  0.008 0.018 0.510 1.789 2.520 0.458 0.040 0.092  0.050 0.008 0.906 1.519 2.731 0.886 0.010 0.128  0.095 0.013 1.017 1.512 2.731 0.925 0.007 0.156  0.080 0.008 1.300 1.767 2.464 0.131 0.114 0.035  0.133 0.012 1.201 1.641 2.740 0.539 0.028 0.040  0.078 0.014 1.177 1.695 2.611 0.493 0.038 0.064  0.096 0.269 0.681 1.521 3.238 0.471 0.071 0.078  0.102 0.015 0.988 1.556 2.749 0.918 0.008 0.140  0.057 0.014 1.002 1.555 2.752 0.925 0.007 0.064  Table 11-B  0.000 0.033 2.604 2.000 12.000  0.000 0.022 2.281 1.992 11.992  0.002 0.058 1.580 1.950 11.950  0.000 0.051 1.414 1.905 11.905  0.000 0.073 1.795 1.920 11.920  0.000 0.065 1.407 1.867 11.867  0.002 0.061 1.576 1.922 11.922  0.001 0.022 0.943 1.904 11.904  0.000 0.038 1.388 1.898 11.898  0.001 0.055 1.501 1.943 11.943  Cation Sum Anion Sum  7.717 12.000  7.731 12.000  7.827 12.000  7.826 12.000  7.687 12.000  7.674 12.000  7.731 12.000  7.294 12.000  7.800 12.000  7.876 12.000  Sample  00  Garnet/Biotite Microprobe Data  CR3+ MN2+ FE2+ H+ 02-  F18-41  F18-42  FC18-4  FC18-6  F18-10  F18-12  F18-13  F18-17  F18-20  F18-21  F NA2O MGO AL203 S102 K2O CAO TIO2 CR203 MNO FEO H2O * 0=F  0.24 0.62 8.75 16.38 33.46 9.12 0.05 1.91 0.00 0.66 20.62 3.60 -0.10  0.39 0.34 9.12 17.15 34.42 8.04 0.09 1.65 0.00 0.63 20.87 3.60 -0.16  0.09 0.77 3.38 17.17 27.08 1.56 0.34 3.57 0.00 0.31 31.31 3.32 -0.04  0.08 0.16 3.80 18.46 34.22 8.85 0.04 1.64 0.00 0.45 28.99 3.77 -0.03  0.00 0.06 4.20 18.22 31.68 5.81 0.21 1.50 0.00 0.42 30.34 3.65 0.00  0.00 0.07 4.54 18.51 27.96 1.85 0.07 0.82 0.02 0.45 35.31 3.49 0.00  0.10 0.21 3.85 18.64 31.78 5.60 0.26 1.26 0.02 0.31 30.38 3.60 -0.04  0.02 0.17 4.35 17.41 26.90 1.39 0.28 1.15 0.00 0.30 36.17 3.39 -0.01  0.32 0.00 7.19 16.76 35.35 9.68 0.03 1.58 0.04 0.73 25.26 3.70 -0.13  0.24 0.28 6.88 16.16 33.99 9.79 0.09 1.98 0.05 0.68 24.64 3.64 -0.10  TOTAL  95.30  96.13  88.87  100.43  96.09  93.09  95.97  91.52  100.51  98.32  FNA+ MG2+ AL3+ S14+ K+ CA2+  0.061 0.097 1.054 1.561 2.705 0.941 0.004  0.098 0.052 1.078 1.602 2.728 0.813 0.008  0.025 0.133 0.449 1.803 2.412 0.177 0.032  0.020 0.024 0.446 1.713 2.695 0.889 0.003  0.000 0.010 0.515 1.765 2.604 0.609 0.018  0.000 0.012 0.582 1.876 2.405 0.203 0.006  0.026 0.033 0.472 1.805 2.611 0.587 0.023  0.006 0.029 0.572 1.811 2.374 0.156 0.026  0.079 0.000 0.834 1.536 2.750 0.961 0.003  0.061 0.043 0.820 1.522 2.716 0.998 0.008  Table 11-B T14+ CR3+ MN2+ FE2+ H+ 02Cation Sum Anion Sum Sample  Garnet/Biotite Microprobe Data 0.239 0.116 0.098 0.000 0.000 0.000 0.042 0.023 0.045 1.383 2.333 1.394 1.939 1.902 1.975 11.975 11.939 11.902  0.097 0.000 0.030 1.909 1.980 11.980  0.093 0.000 0.029 2.086 2.000 12.000  0.053 0.001 0.033 2.540 2.000 12.000  0.078 0.001 0.022 2.087 1.974 11.974  0.076 0.000 0.022 2.669 1.994 11.994  0.092 0.002 0.048 1.643 1.921 11.921  0.119 0.003 0.046 1.647 1.939 11.939  7.602 12.000  7.808 12.000  7.730 12.000  7.711 12.000  7.718 12.000  7.737 12.000  7.869 12.000  7.923 12.000  7.917 12.000 F18-22  7.805 12.000 F18-24  F18-25  F18-26  F18-28  F18-29  F18-34  F18-35  F18-38  F18-39  F NA2O MGO AL203 S102 K2O CAO 1102 CR203 MNO FEO H2O * 0=F  0.37 0.10 6.94 16.80 34.46 7.85 0.17 1.69 0.00 0.71 24.37 3.58 -0.16  0.49 0.08 8.06 16.66 35.00 9.42 0.08 1.63 0.00 0.60 23.62 3.59 -0.21  0.27 0.10 8.76 16.28 33.93 7.64 0.22 2.00 0.04 0.88 23.95 3.65 -0.11  0.45 0.07 8.45 16.82 35.28 9.41 0.09 2.07 0.03 0.73 23.05 3.66 -0.19  0.37 0.07 9.54 17.23 34.20 7.46 0.22 0.72 0.00 0.80 20.90 3.57 -0.16  0.41 0.05 11.21 18.21 29.88 1.26 0.76 0.59 0.00 1.36 25.61 3.45 -0.17  0.44 0.06 8.85 17.35 35.06 8.77 0.14 1.35 0.00 0.61 22.47 3.64 -0.19  0.38 0.07 11.78 18.76 31.99 2.76 0.34 0.87 0.05 1.02 22.72 3.58 -0.16  0.40 0.09 8.81 17.22 35.64 9.26 0.07 1.29 0.07 0.73 22.63 3.69 -0.17  0.25 0.11 10.51 18.39 31.35 2.22 0.27 1.26 0.02 1.05 24.47 3.59 -0.11  TOTAL  96.88  99.03  97.61  99.92  94.92  92.62  98.55  94.16  99.74  93.38  FNA+ MG2+ AL3+ S14+ K+  0.093 0.015 0.826 1.581 2.751 0.800  0.121 0.012 0.942 1.539 2.743 0.942  0.068 0.015 1.035 1.521 2.690 0.773  0.110 0.011 0.975 1.534 2.731 0.929  0.094 0.011 1.139 1.626 2.738 0.762  0.107 0.008 1.374 1.765 2.457 0.132  0.108 0.009 1.028 1.594 2.733 0.872  0.096 0.011 1.398 1.761 2.548 0.280  0.098 0.013 1.014 1.567 2.751 0.912  0.064 0.017 1.268 1.753 2.536 0.229  Table 11-B  0.015 0.101 0.000 0.048 1.627 1.907 11.907  0.007 0.096 0.000 0.040 1.548 1.879 11.879  0.019 0.119 0.003 0.059 1.588 1.932 11.932  0.007 0.121 0.002 0.048 1.492 1.890 11.890  0.019 0.043 0.000 0.054 1.399 1.906 11.906  0.067 0.036 0.000 0.095 1.761 1.893 11.893  0.012 0.079 0.000 0.040 1.465 1.892 11.892  0.029 0.052 0.003 0.069 1.513 1.904 11.904  0.006 0.075 0.004 0.048 1.461 1.902 11.902  0.023 0.077 0.001 0.072 1.656 1.936 11.936  Cation Sum Anion Sum  7.764 12.000  7.868 12.000  7.823 12.000  7.850 12.000  7.792 12.000  7.695 12.000  7.832 12.000  7.664 12.000  7.851 12.000  7.633 12.000  Sample  I' c) -  Garnet/Biotite Microprobe Data  CA2+ T14+ CR3+ MN2+ FE2+ H+ 02-  PL31-1  PL31-2  PL31-3  PL31-4  PL31-5  PL31-6  PL31-7  PL31-8  PL31-9  P31-10  F NA2O MGO AL203 S102 K2O CAO 1102 CR203 MNO FEO H2O * 0=F  0.24 0.11 7.35 17.66 35.36 8.89 0.10 2.41 0.00 0.31 22.19 3.74 -0.10  0.09 0.07 12.81 20.86 24.76 0.02 0.01 0.06 0.02 0.46 28.12 3.49 -0.04  0.06 0.23 7.74 17.91 35.37 8.98 0.07 1.96 0.01 0.13 20.62 3.80 -0.03  0.19 0.48 5.52 17.40 25.84 2.74 3.93 0.89 0.05 0.30 19.71 3.05 -0.08  0.18 0.29 7.67 18.81 35.32 8.45 0.10 1.64 0.01 0.16 20.55 3.76 -0.08  0.08 0.08 8.03 17.24 36.49 8.99 0.12 1.90 0.03 0.31 20.48 3.82 -0.03  0.00 0.21 11.73 21.01 25.44 0.13 0.03 0.07 0.12 0.42 28.18 3.54 0.00  0.01 0.05 12.99 20.57 25.22 0.04 0.05 0.09 0.02 0.69 28.26 3.56 0.00  0.16 0.76 7.42 13.53 41.15 2.51 7.88 0.73 0.00 0.39 21.55 3.94 -0.07  0.18 0.06 8.50 17.61 36.16 9.53 0.02 1.84 0.00 0.19 21.67 3.82 -0.08  TOTAL  98.25  90.73  96.85  80.02  96.86  97.54  90.88  91.54  99.96  99.51  FNA+ MG2+ AL3+ S14+  0.059 0.017 0.853 1.621 2.754  0.024 0.012 1.621 2.087 2.101  0.015 0.035 0.905 1.655 2.774  0.057 0.089 0.786 1.958 2.467  0.044 0.044 0.893 1.731 2.757  0.020 0.012 0.930 1.578 2.834  0.000 0.034 1.480 2.095 2.153  0.003 0.008 1.630 2.041 2.123  0.038 0.110 0.825 1.189 3.069  0.044 0.009 0.972 1.593 2.775  Table 11-B  Garnet/Biotite Microprobe Data  K+ CA2+ T14+ CR3+ MN2+ FE2+ H+ 02-  0.883 0.008 0.141 0.000 0.020 1.445 1.941 11.941  0.002 0.001 0.004 0.001 0.033 1.996 1.976 11.976  0.898 0.006 0.116 0.001 0.009 1.352 1.985 11.985  0.334 0.402 0.064 0.004 0.024 1.574 1.943 11.943  0.842 0.008 0.096 0.001 0.011 1.342 1.956 11.956  0.891 0.010 0.111 0.002 0.020 1.330 1.980 11.980  0.014 0.003 0.004 0.008 0.030 1.994 2.000 12.000  0.004 0.005 0.006 0.001 0.049 1.989 1.997 11.997  0.239 0.630 0.041 0.000 0.025 1.344 1.962 11.962  0.933 0.002 0.106 0.000 0.012 1.391 1.956 11.956  Cation Sum Anion Sum  7.744 12.000  7.858 12.000  7.750 12.000  7.700 12.000  7.723 12.000  7.717 12.000  7.815 12.000  7.856 12.000  7.470 12.000  7.793 12.000  Sample  P31-11  P31-12  P31-13  P31-14  P31-15  P31-16  P31-17  P31-18  P31-19  FC16-1  F NA2O MGO AL203 S102 K2O CAO 1102 CR203 MNO FEO H2O * 0=F  0.00 0.02 12.88 20.69 25.34 0.02 0.04 0.09 0.02 0.54 28.28 3.57 0.00  0.11 0.12 9.66 18.01 32.41 5.45 0.32 1.30 0.00 0.31 24.04 3.69 -0.05  0.00 0.05 12.96 20.56 25.42 0.07 0.04 0.06 0.01 0.49 28.10 3.56 0.00  0.05 0.07 9.56 16.41 27.75 0.12 4.28 4.81 0.00 0.30 26.37 3.60 -0.02  0.01 0.54 11.19 19.12 29.02 0.67 0.08 0.24 0.00 0.36 27.96 3.64 0.00  0.06 1.04 6.71 13.21 43.15 0.29 10.91 0.09 0.01 0.49 21.24 4.08 -0.03  0.00 0.12 8.18 17.35 35.63 9.48 0.06 2.01 0.04 0.30 21.66 3.86 0.00  0.19 0.03 8.30 17.36 36.53 9.64 0.00 2.10 0.00 0.30 21.55 3.83 -0.08  0.09 1.29 6.59 14.05 42.72 0.40 11.19 0.31 0.00 0.65 20.44 4.09 -0.04  0.13 0.07 8.50 16.28 36.42 9.15 0.08 3.02 0.00 0.15 22.32 3.85 -0.05  TOTAL  91.49  95.37  91.32  93.30  92.82  101.26  98.69  99.75  101.78  99.92  FNA+ MG2+ AL3+  0.000 0.003 1.615 2.051  0.028 0.019 1.154 1.700  0.000 0.008 1.627 2.040  0.013 0.011 1.178 1.599  0.003 0.086 1.373 1.855  0.014 0.147 0.729 1.135  0.000 0.018 0.946 1.586  0.046 0.004 0.947 1.566  0.021 0.181 0.712 1.201  0.031 0.010 0.971 1.470  Table 11-B S14+ K+ CA2+ T14+ CR3+ MN2+ FE2+ H+ 02Cation Sum Anion Sum Sample  _ I' N -  Garnet/Biotite Microprobe Data 2.140 2.596 2.131 0.008 0.557 0.002 0.027 0.004 0.004 0.078 0.004 0.006 0.000 0.001 0.001 0.021 0.035 0.038 1.978 1.610 1.989 1.972 2.000 2.000 12.000 12.000 11.972 7.840 12.000 FC16-2  7.763 12.000 FC16-3  7.844 12.000 FC16-4  2.295 0.013 0.379 0.299 0.000 0.021 1.823 1.987 11.987  2.389 0.070 0.007 0.015 0.000 0.025 1.925 1.997 11.997  3.146 0.027 0.852 0.005 0.001 0.030 1.295 1.986 11.986  2.764 0.938 0.005 0.117 0.002 0.020 1.405 2.000 12.000  2.796 0.941 0.000 0.121 0.000 0.019 1.379 1.954 11.954  3.098 0.037 0.869 0.017 0.000 0.040 1.239 1.979 11.979  2.789 0.894 0.007 0.174 0.000 0.010 1.430 1.969 11.969  7.619 12.000  7.747 12.000  7.368 12.000  7.802 12.000  7.773 12.000  7.394 12.000  7.754 12.000  FC16-5  FC16-6  FC16-7  FC16-8  FC16-9  F16-10  F16-11  F NA2O MGO AL203 S102 K2O CAO 1102 CR203 MNO FEO H2O * 0=F  0.15 0.06 8.81 16.46 35.35 8.83 0.05 2.56 0.03 0.22 22.50 3.79 -0.06  0.24 0.07 8.69 16.09 35.54 9.32 0.06 3.03 0.00 0.37 22.37 3.76 -0.10  0.08 1.26 7.97 11.67 43.71 0.57 11.02 0.57 0.00 0.52 20.19 4.09 -0.03  0.10 0.03 8.63 16.22 35.78 9.75 0.06 3.03 0.00 0.23 22.22 3.84 -0.04  0.34 0.05 8.80 16.36 36.22 9.48 0.04 2.96 0.06 0.34 21.51 3.75 -0.14  0.06 0.05 10.36 19.95 25.88 0.13 0.06 0.10 0.00 0.40 30.61 3.48 -0.03  0.11 0.14 7.70 16.87 35.44 8.98 0.07 2.32 0.00 0.18 23.20 3.80 -0.05  0.06 0.20 11.23 19.76 26.03 0.83 0.05 0.48 0.02 0.33 28.40 3.50 -0.03  0.17 0.08 7.64 16.43 35.92 9.34 0.07 2.88 0.03 0.18 24.10 3.82 -0.07  0.23 0.06 7.72 17.31 34.49 8.21 0.08 2.04 0.04 0.16 22.80 3.67 -0.10  TOTAL  98.74  99.44  101.62  99.85  99.76  91.06  98.76  90.86  100.59  96.72  FNA+ MG2+  0.037 0.009 1.021  0.059 0.011 1.003  0.018 0.177 0.863  0.024 0.004 0.991  0.082 0.007 1.006  0.016 0.008 1.319  0.027 0.021 0.894  0.016 0.033 1.424  0.041 0.012 0.876  0.058 0.009 0.912  Table 11-B  Garnet/Biotite Microprobe Data  AL3+ S14+ K+ CA2+ 114+ CR3+ MN2+ FE2+ H+ 02-  1.507^1.468^0.999^1.473 2.747^2.750^3.174^2.757 0.875^0.920^0.053^0.958 0.004^0.005^0.857^0.005 0.150^0.176^0.031^0.176 0.002^0.000^0.000^0.000 0.014^0.024^0.032^0.015 1.462^1.448^1.226^1.432 1.963^1.941^1.982^1.976 11.963^11.941^11.982^11.976  1.479 2.778 0.928 0.003 0.171 0.004 0.022 1.380 1.918 11.918  2.009 2.211 0.014 0.005 0.006 0.000 0.029 2.187 1.984 11.984  1.549 2.762 0.893 0.006 0.136 0.000 0.012 1.512 1.973 11.973  1.981 2.215 0.090 0.005 0.031 0.001 0.024 2.021 1.984 11.984  1.489 2.762 0.916 0.006 0.167 0.002 0.012 1.550 1.959 11.959  1.617 2.734 0.830 0.007 0.122 0.003 0.011 1.511 1.942 11.942  Cation Sum Anion Sum  7.791^7.805^7.411^7.812 12.000^12.000^12.000^12.000  7.777 12.000  7.789 12.000  7.785 12.000  7.825 12.000  7.790 12.000  7.755 12.000  Sample  F16-12^F16-13^F16-14^F16-15  F NA2O MGO AL203 S102 K2O CAO 1102 CR203 MNO FEO H2O * 0=F  0.03^0.10^0.12^0.20 0.06^0.10^0.14^0.07 7.15^7.44^7.17^7.66 17.33^17.38^17.17^17.26 34.44^36.19^35.16^33.93 7.69^8.75^8.32^6.82 0.16^0.07^0.15^0.16 2.40^2.52^2.34^2.63 0.04^0.01^0.04^0.00 0.17^0.11^0.09^0.11 23.84^23.40^23.54^24.63 3.78^3.86^3.77^3.69 -0.01^-0.04^-0.05^-0.08  TOTAL  97.07^99.89^97.96^97.08  FNA+  0.008^0.024^0.030^0.050 0.009^0.015^0.021^0.011  Table 11-B  Garnet/Biotite Microprobe Data  MG2+ AL3+ S14+ K+ CA2+ 114+ CR3+ MN2+ FE2+ H+ 02-  0.843 1.616 2.725 0.776 0.014 0.143 0.003 0.011 1.577 1.992 11.992  0.851 1.571 2.776 0.856 0.006 0.145 0.001 0.007 1.501 1.976 11.976  0.838 1.587 2.757 0.832 0.013 0.138 0.002 0.006 1.544 1.970 11.970  0.903 1.609 2.685 0.688 0.014 0.157 0.000 0.007 1.630 1.950 11.950  Cation Sum Anion Sum  7.716 12.000  7.728 12.000  7.737 12.000  7.704 12.000  Garnet/Biotite Calculations  Table II-C Garnet mineral ID FC-18-1 FC-18-4 FC-18-6 FC-18-7 FC-18-8 FC-18-10 FC-18-12 FC-18-14 FC-18-16 FC-18-17 FC-18-19 FC-18-21  Biotite mineral ID FC18-1 FC18-2 FC18-4 FC18-5 FC18-6 FC18-8 FC18-9 FC18-10 FC18-12 FC18-15 FC18-16 FC18-17  cation ratios Fe (g)^Mg (g) 0.072 0.008 0.043 0.006 0.005 0.069 0.082 0 0.088 0.002 0.005 0.1 0.097 0.001 0.086 0.001 0.087 0.002 0.004 0.048 0 0.053 0.012 0.07  PL7-23 PL7-25 PL7-27 PL7-29 PL7-31 PL7-33 PL7-35 PL7-36 PL7-37 PL7-39 PL7-40 PL7-41 PL7-42 PL7-43 PL7-44 PL7-45  PL7-20 PL7-22 PL7-24 PL7-25 PL7-27 PL7-30 PL7-29 PL7-32 PL7-33 PL7-34 PL7-35 PL7-36 PL7-38 PL7-37 PL7-39 PL7-41  0.085 0.103 0.128 0.119 0.117 0.129 0.094 0.081 0.107 0.119 0.134 0.078 0.116 0.109 0.093 0.129  0.007 0.023 0.003 0.008 0 0.001 0.003 0 0.008 0 0 0.002 0.004 0 0.01 0.01  PL31-1 PL31-3 PL31-4 PL31-6 PL31-8 PL31-10 PL31-12 PL31-14 PL31-16 PL31-18 PL31-19 PL31-21  PL31-1 PL31-3 PL31-4 PL31-5 PL31-6 PL31-7 PL31-8 PL31-9 PL31-11 PL31-12 PL31-13 PL31-15  0.313 0.292 0.3 0.253 0.289 0.302 0.247 0.193 0.27 0.351 0.335 0.332  0.008 0.007 0.009 0.006 0.011 0.006 0.008 0.005 0 0.004 0.004 0.004  Fe (b)^Mg (b) 2.003^0.458 2.641^0.57 2.332^0.449 2.335^0.566 1.909^0.446 1.835^0.406 2.819^0.644 2.086^0.515 2.54^0.582 2.851^0.652 2.816^0.627 2.669^0.573 Mean Standard Error Standar Deviation 1.643^0.834 1.548^0.942 1.58^0.906 1.589^1.036 1.414^1.017 1.795^1.3 1.761^1.374 1.576^1.177 0.943^0.681 1.465^1.029 1.514^1.399 1.388^0.988 1.462^1.015 1.502^1.002 1.656^1.267 1.394^1.055 Mean Standard Error Standar Deviation 1.446^0.854 1.353^0.904 1.575^0.786 1.341^0.893 1.33^0.93 2^1.481 1.99^1.63 1.344^0.825 1.989^1.615 1.61^1.153 1.978^1.627 1.925^1.373  T 692.28 755.48 763.03 712.78 692.72 706.36 698.65 701.85 738.92 741.33 727.19 738.23 722.40 7.16 24.82 707.82 588.17 619.45 562.87 546.32 454.57 478.79 497.15 508.11 552.74 461.82 532.40 515.79 518.39 523.28 521.41 536.82 15.69 62.77 591.61 576.76 620.93 583.23 562.11 533.51 536.61 610.46 511.03 540.68 486.62 550.65  145  Table II-C  Garnet/Biotite Calculations cation ratios Fe (g)^Mg (g) Fe (b)^Mg (b)  Garnet mineral ID  Biotite mineral ID  PL31-23 PL31-25  PL31-16 PL31-17  0.323 0.333  0.003 0.006  FC16-1 FC16-2 FC16-4 FC16-5 FC16-7 FC16-9 FC16-11 FC16-12 FC16-13 FC16-15 FC16-17 FC16-19  FC16-1 FC16-1 FC16-3 FC16-5 FC16-7 FC16-8 FC16-9 FC16-10 FC16-11 FC16-12 FC16-13 FC16-15  0.553 0.664 0.569 0.559 0.409 0.395 0.394 0.457 0.384 0.396 0.464 0.437  0.005 0.004 0.003 0.003 0.011 0.007 0.007 0.003 0.004 0.004 0.003 0.007  1.295^0.73 1.405^0.946 Mean Standard Error Standar Deviation 1.462^1.021 1.43^0.971 1.405^0.946 1.432^0.991 2.187^1.32 1.512^0.894 2.021^1.424 1.55^0.876 1.512^0.913 1.577^0.844 1.501^0.851 1.63^0.904 Mean Standard Error Standar Deviation  T 634.66 564.79 564.55 11.21 41.96 568.89 575.58 613.19 604.68 578.55 595.28 520.81 596.84 579.80 604.05 582.29 599.53 584.96 7.04 24.39  146  Table II-D  Amphibole/Plagioclase Microprobe Data  AMPHIBOLE Sample  _ -1' ,1  PL2-7  PL2-6  PL2-5  PL2-1^PL2-2^PL2-3^PL2-4  PL2-9  PL2-8  PL2-10  F NA2O MGO AL203 S102 K20 CAO T102 CR203 MNO FEO H2O * 0=F  0.18 0.90 10.42 9.31 44.28 0.92 11.63 0.91 0.00 0.54 18.14 1.89 -0.08  0.00 1.05 8.85 11.25 41.98 1.17 11.77 0.72 0.00 0.67 19.63 1.95 0.00  0.00 1.17 9.08 11.97 41.91 0.92 11.46 0.51 0.01 0.62 19.01 1.95 0.00  0.07 1.00 9.71 10.80 43.80 0.63 11.75 0.30 0.02 0.67 18.93 1.95 -0.03  0.02 1.03 9.50 10.88 43.25 0.93 11.68 0.52 0.02 0.69 18.17 1.95 -0.01  0.08 0.98 9.65 10.55 43.07 0.89 11.79 0.89 0.01 0.74 18.87 1.93 -0.03  0.18 0.95 9.82 9.99 42.88 0.97 11.90 0.94 0.01 0.67 18.44 1.87 -0.08  0.00 0.00 0.03 22.75 37.93 0.00 22.46 0.09 0.04 0.61 12.33 1.97 0.00  0.04 0.00 0.04 23.55 37.79 0.01 23.28 0.06 0.00 0.38 11.70 1.97 -0.02  0.06 1.14 9.00 11.78 42.00 0.78 11.70 0.37 0.00 0.67 19.30 1.92 -0.03  TOTAL  99.04  99.04  98.61  99.60  98.64  99.42  98.54  98.21  98.80  98.70  FNA+ MG2+ AL3+ S14+ K+ CA2+ T14+ CR3+ MN2+ FE2+ H+ 02-  0.086 0.265 2.359 1.666 6.724 0.178 1.892 0.104 0.000 0.069 2.304 1.914 23.914  0.000 0.313 2.030 2.040 6.459 0.230 1.940 0.083 0.000 0.087 2.526 2.000 24.000  0.000 0.348 2.079 2.167 6.438 0.180 1.886 0.059 0.001 0.081 2.442 2.000 24.000  0.033 0.293 2.190 1.926 6.628 0.122 1.905 0.034 0.002 0.086 2.395 1.967 23.967  0.010 0.305 2.163 1.958 6.606 0.181 1.911 0.060 0.002 0.089 2.321 1.990 23.990  0.039 0.289 2.190 1.893 6.557 0.173 1.923 0.102 0.001 0.095 2.402 1.961 23.961  0.087 0.283 2.248 1.808 6.585 0.190 1.958 0.109 0.001 0.087 2.368 1.913 23.913  0.000 0.000 0.007 4.079 5.770 0.000 3.661 0.010 0.005 0.079 1.569 2.000 24.000  0.019 0.000 0.009 4.188 5.703 0.002 3.764 0.007 0.000 0.049 1.476 1.981 23.981  0.029 0.340 2.062 2.134 6.455 0.153 1.927 0.043 0.000 0.087 2.481 1.971 23.971  ^  Table II-D  Amphibole/Plagioclase Microprobe Data  ^15.561^15.709^15.683^15.582 Cation Sum 24.000^24.000^24.000^24.000 Anion Sum  Sample  _ I' 00 -  PL2-11  PL2-12  PL2-13  PL2-14  15.597 24.000 PL2-15  15.625 24.000 PL2-16  15.638 24.000 PL2-17  15.178 24.000 PL2-18  15.198 24.000 HH2-1  15.681 24.000 HH2-2  F NA2O MGO AL203 S102 K2O CAO TIO2 CR203 MNO FEO H2O * 0=F  0.10 1.00 9.32 10.75 41.96 1.18 11.71 0.87 0.00 0.61 19.17 1.89 -0.04  0.00 1.11 9.12 11.51 42.03 0.92 11.74 0.42 0.00 0.70 19.23 1.95 0.00  0.03 0.94 9.49 10.49 42.06 1.21 11.65 1.04 0.04 0.53 18.85 1.93 -0.01  0.08 0.95 9.50 10.57 42.58 1.16 11.58 1.02 0.00 0.63 19.09 1.92 -0.03  0.03 1.03 9.54 10.50 42.47 1.12 11.89 0.85 0.02 0.50 19.26 1.94 -0.01  0.16 1.21 9.87 10.94 43.04 0.60 11.46 0.48 0.00 0.66 17.63 1.88 -0.07  0.06 1.01 9.52 10.71 42.23 1.13 11.60 0.98 0.00 0.64 18.29 1.91 -0.03  0.00 1.02 9.42 10.55 42.23 1.31 11.54 0.85 0.00 0.72 18.66 1.94 0.00  0.07 1.19 9.79 11.64 42.88 0.51 11.57 0.45 0.02 0.67 17.50 1.93 -0.03  0.00 0.69 12.39 7.32 46.78 0.46 11.76 0.75 0.00 0.72 15.59 2.00 0.00  TOTAL  98.52  98.73  98.24  99.05  99.14  97.86  98.06  98.24  98.19  98.46  FNA+ MG2+ AL3+ S14+ K+ CA2+ T14+ CR3+ MN2+ FE2+ H+  0.049 0.299 2.145 1.956 6.479 0.232 1.937 0.101 0.000 0.080 2.476 1.951  0.000 0.331 2.091 2.086 6.464 0.181 1.935 0.049 0.000 0.091 2.473 2.000  0.015 0.282 2.187 1.911 6.501 0.239 1.929 0.121 0.005 0.069 2.437 1.985  0.039 0.282 2.170 1.909 6.524 0.227 1.901 0.118 0.000 0.082 2.446 1.961  0.015 0.306 2.181 1.897 6.512 0.219 1.953 0.098 0.002 0.065 2.470 1.985  0.078 0.360 2.256 1.977 6.600 0.117 1.883 0.055 0.000 0.086 2.261 1.922  0.029 0.302 2.190 1.948 6.518 0.222 1.918 0.114 0.000 0.084 2.361 1.971  0.000 0.306 2.170 1.921 6.526 0.258 1.911 0.099 0.000 0.094 2.411 2.000  0.034 0.352 2.227 2.094 6.544 0.099 1.892 0.052 0.002 0.087 2.233 1.966  0.000 0.201 2.771 1.294 7.018 0.088 1.890 0.085 0.000 0.091 1.956 2.000  ^  Table II-D  Amphibole/Plagioclase Microprobe Data  23.985^23.961 ^23.951^24.000^ 02-  23.985  23.922  23.971  24.000  23.966  24.000  15.707^15.700^15.680^15.658 24.000^24.000^24.000^24.000  15.703 24.000  15.595 24.000  15.657 24.000  15.697 24.000  15.582 24.000  15.394 24.000  Cation Sum Anion Sum Sample  _ 4. ■o '  HH2-3  HH2-4  HH2-5  HH2-6  HH2-7  HH2-8  HH2-9  HH2-10  HH2-11  HH2-12  F NA2O MGO AL203 S102 K2O CAO TIO2 CR203 MNO FEO H2O * 0=F  0.04 0.81 11.89 8.87 45.93 0.53 11.74 0.46 0.01 0.69 16.31 1.99 -0.02  0.00 1.20 9.44 12.04 42.61 0.62 11.48 0.46 0.00 0.74 17.93 1.97 0.00  0.08 0.88 10.40 8.37 49.43 0.48 10.67 0.49 0.00 0.66 15.29 1.99 -0.03  0.00 0.76 12.93 6.89 47.37 0.34 11.87 0.53 0.03 0.72 15.48 2.01 0.00  0.00 1.26 8.88 13.76 41.14 0.70 11.67 0.40 0.00 0.64 18.31 1.96 0.00  0.05 0.89 11.15 9.68 44.85 0.72 11.64 0.77 0.06 0.67 16.36 1.97 -0.02  0.00 1.05 10.55 10.00 44.00 0.74 11.60 0.78 0.00 0.72 17.39 1.98 0.00  0.07 1.32 9.05 13.40 41.36 0.50 11.62 0.31 0.04 0.72 18.39 1.93 -0.03  0.00 1.27 9.59 11.90 42.26 0.54 11.64 0.53 0.00 0.66 17.65 1.96 0.00  0.25 0.93 10.91 10.12 43.90 0.82 11.63 0.80 0.00 0.62 16.80 1.86 -0.11  TOTAL  99.25  98.49  98.71  98.93  98.72  98.79  98.81  98.68  98.00  98.53  FNA+ MG2+ AL3+ S14+ K+ CA2+ T14+ CR3+ MN2+ FE2+  0.019 0.235 2.649 1.562 6.864 0.101 1.880 0.052 0.001 0.087 2.038  0.000 0.355 2.147 2.165 6.501 0.121 1.877 0.053 0.000 0.096 2.288  0.037 0.252 2.288 1.456 7.295 0.090 1.687 0.054 0.000 0.083 1.887  0.000 0.220 2.874 1.211 7.063 0.065 1.896 0.059 0.004 0.091 1.930  0.000 0.373 2.023 2.479 6.288 0.136 1.911 0.046 0.000 0.083 2.341  0.024 0.260 2.504 1.718 6.755 0.138 1.878 0.087 0.007 0.085 2.061  0.000 0.309 2.385 1.787 6.673 0.143 1.885 0.089 0.000 0.092 2.206  0.034 0.391 2.062 2.414 6.323 0.098 1.903 0.036 0.005 0.093 2.351  0.000 0.378 2.192 2.150 6.479 0.106 1.912 0.061 0.000 0.086 2.263  0.120 0.274 2.467 1.809 6.659 0.159 1.890 0.091 0.000 0.080 2.131  Table II-D  1.981 23.981  2.000 24.000  1.963 23.963  2.000 24.000  2.000 24.000  1.976 23.976  2.000 24.000  1.966 23.966  2.000 24.000  1.880 23.880  Cation Sum Anion Sum  15.470 24.000  15.602 24.000  15.093 24.000  15.413 24.000  15.681 24.000  15.494 24.000  15.570 24.000  15.676 24.000  15.626 24.000  15.561 24.000  Sample  ' c)  Amphibole/Plagioclase Microprobe Data  H+ 02-  HH2-13  HH2-14  HH2-15  HH2-16  HH2-17  HH2-18  HH2-19  HH2-20  HH2-21  HH2-22  F NA2O MGO AL203 S102 K2O CAO 1102 CR203 MNO FE0 H2O * 0=F  0.00 1.11 9.51 11.86 42.72 0.59 11.67 0.49 0.00 0.73 18.03 1.97 0.00  0.09 1.07 7.31 10.52 35.82 0.45 9.81 7.34 0.00 1.44 21.66 1.83 -0.04  0.00 1.28 9.03 13.35 41.53 0.52 11.49 0.45 0.06 0.64 18.00 1.96 0.00  0.00 1.04 10.72 10.97 43.64 0.84 11.74 0.80 0.01 0.65 16.36 1.98 0.00  0.08 1.10 10.70 11.35 42.80 0.51 11.43 0.67 0.00 0.60 16.43 1.92 -0.03  0.07 1.23 7.19 15.52 39.86 0.68 11.39 0.10 0.00 0.73 19.42 1.91 -0.03  0.07 1.07 10.95 10.56 44.31 0.62 11.53 0.57 0.00 0.72 16.59 1.96 -0.03  0.07 1.23 9.29 12.15 42.17 0.57 11.52 0.47 0.01 0.72 18.32 1.93 -0.03  0.14 1.00 10.72 10.25 44.24 0.81 11.65 0.73 0.00 0.69 16.94 1.92 -0.06  0.18 1.22 9.65 12.26 42.42 0.56 11.53 0.48 0.05 0.66 17.75 1.88 -0.08  TOTAL  98.68  97.30  98.31  98.75  97.56  98.07  98.92  98.42  99.03  98.57  FNA+ MG2+ AL3+ S14+ K+ CA2+ 114+ CR3+ MN2+  0.000 0.328 2.160 2.129 6.508 0.115 1.905 0.056 0.000 0.094  0.046 0.333 1.748 1.989 5.747 0.092 1.686 0.886 0.000 0.196  0.000 0.380 2.059 2.407 6.353 0.101 1.883 0.052 0.007 0.083  0.000 0.305 2.415 1.953 6.594 0.162 1.901 0.091 0.001 0.083  0.039 0.326 2.438 2.044 6.540 0.099 1.871 0.077 0.000 0.078  0.034 0.369 1.658 2.829 6.165 0.134 1.887 0.012 0.000 0.096  0.033 0.312 2.458 1.874 6.672 0.119 1.860 0.065 0.000 0.092  0.034 0.365 2.120 2.192 6.457 0.111 1.890 0.054 0.001 0.093  0.067 0.293 2.412 1.823 6.677 0.156 1.884 0.083 0.000 0.088  0.087 0.360 2.192 2.201 6.462 0.109 1.882 0.055 0.006 0.085  Table II-D  Amphibole/Plagioclase Microprobe Data  FE2+ H+ 02-  2.297 2.000 24.000  2.906 1.954 23.954  2.303 2.000 24.000  2.067 2.000 24.000  2.100 1.961 23.961  2.512 1.966 23.966  2.089 1.967 23.967  2.346 1.966 23.966  2.138 1.933 23.933  2.261 1.913 23.913  Cation Sum Anion Sum  15.592 24.000  15.585 24.000  15.629 24.000  15.571 24.000  15.573 24.000  15.661 24.000  15.542 24.000  15.631 24.000  15.553 24.000  15.614 24.000  Sample  HH2-23  HH2-24  HH2-25  HH2-26  HH2-27  HH2-28  FC16-1  FC16-2  FC16-3  FC16-4  F NA2O MGO AL203 S102 K2O CAO 1102 CR203 MNO FEO H2O * 0=F  0.07 0.84 12.15 8.79 46.49 0.59 11.84 0.83 0.00 0.65 15.28 1.99 -0.03  0.04 7.35 0.00 24.91 58.98 0.06 7.12 0.00 0.00 0.00 0.34 2.29 -0.02  0.00 0.90 11.62 9.34 45.44 0.51 11.65 0.61 0.05 0.72 16.65 2.01 0.00  0.00 1.13 9.96 12.39 42.54 0.71 11.64 0.47 0.00 0.60 17.26 1.98 0.00  0.06 1.27 8.76 12.53 41.86 0.65 11.53 0.58 0.00 0.65 18.35 1.92 -0.03  0.09 0.94 10.71 10.12 44.23 0.67 11.54 0.56 0.03 0.65 17.19 1.94 -0.04  0.03 1.35 6.12 13.12 41.74 0.50 11.18 0.63 0.00 0.32 21.60 1.92 -0.01  0.17 1.28 7.53 11.04 42.42 0.45 10.50 0.88 0.07 0.51 21.66 1.85 -0.07  0.03 1.22 6.99 11.78 42.32 0.56 11.07 0.70 0.01 0.52 21.76 1.93 -0.01  0.00 1.17 7.36 11.06 43.29 0.48 11.10 0.69 0.00 0.60 21.10 1.95 0.00  TOTAL  99.49  101.07  99.50  98.68  98.14  98.63  98.50  98.29  98.88  98.80  FNA+ MG2+ AL3+ S14+ K+ CA2+ _^114+ CR3+  0.033 0.242 2.686 1.536 6.895 0.112 1.881 0.093 0.000  0.016 1.851 0.000 3.813 7.661 0.010 0.991 0.000 0.000  0.000 0.261 2.589 1.645 6.791 0.097 1.865 0.069 0.006  0.000 0.333 2.254 2.217 6.458 0.138 1.893 0.054 0.000  0.029 0.378 2.006 2.269 6.431 0.127 1.898 0.067 0.000  0.043 0.276 2.419 1.807 6.700 0.129 1.873 0.064 0.004  0.015 0.405 1.411 2.392 6.457 0.099 1.853 0.073 0.000  0.083 0.385 1.741 2.018 6.578 0.089 1.745 0.103 0.009  0.015 0.365 1.609 2.143 6.533 0.110 1.831 0.081 0.001  0.000 0.349 1.687 2.004 6.654 0.094 1.828 0.080 0.000  Table II-D  0.082 1.895 1.967 23.967  0.000 0.037 1.984 23.984  0.091 2.081 2.000 24.000  0.077 2.191 2.000 24.000  0.085 2.358 1.971 23.971  0.083 2.178 1.957 23.957  0.042 2.794 1.985 23.985  0.067 2.809 1.917 23.917  0.068 2.809 1.985 23.985  0.078 2.712 2.000 24.000  Cation Sum Anion Sum  15.421 24.000  14.363 24.000  15.494 24.000  15.615 24.000  15.620 24.000  15.533 24.000  15.526 24.000  15.543 24.000  15.551 24.000  15.486 24.000  Sample  _ `-^ tv  Amphibole/Plagioclase Microprobe Data  MN2+ FE2+ H+ 02-  FC16-5  FC16-6  FC16-7  FC16-8  FC16-9  F16-10  F16-11  F16-12  F16-13  F16-14  F NA2O MGO AL203 S102 K2O CAO 1102 CR203 MNO FEO H2O * 0=F  0.03 1.22 7.01 11.79 42.48 0.53 11.11 0.85 0.00 0.50 21.62 1.93 -0.01  0.14 1.02 6.64 10.67 42.55 0.62 11.22 0.57 0.00 0.62 23.29 1.86 -0.06  0.00 1.15 6.05 11.57 41.50 0.85 11.50 0.98 0.07 0.46 22.81 1.92 0.00  0.06 1.29 6.60 12.59 41.30 0.71 11.12 0.80 0.00 0.66 21.14 1.90 -0.03  0.10 1.27 7.65 11.62 42.70 0.46 11.08 0.87 0.00 0.63 20.22 1.90 -0.04  0.04 1.25 8.08 10.98 42.20 0.52 10.78 0.70 0.01 0.69 20.58 1.91 -0.02  0.08 1.20 8.13 11.07 43.04 0.47 11.12 0.71 0.03 0.67 20.51 1.92 -0.03  0.01 1.31 7.84 11.63 42.45 0.60 10.92 0.53 0.00 0.69 20.83 1.94 0.00  0.18 1.16 8.39 10.57 44.37 0.43 11.11 0.72 0.02 0.75 20.13 1.89 -0.08  0.11 1.30 7.84 11.50 41.90 0.52 10.80 0.43 0.07 0.74 20.70 1.87 -0.05  TOTAL  99.06  99.15  98.86  98.14  98.46  97.72  98.91  98.75  99.65  97.74  FNA+ MG2+ AL3+ S14+ K+ CA2+ T14+  0.015 0.364 1.608 2.138 6.537 0.104 1.832 0.098  0.069 0.307 1.537 1.953 6.607 0.123 1.867 0.067  0.000 0.348 1.407 2.127 6.472 0.169 1.922 0.115  0.030 0.389 1.532 2.310 6.429 0.141 1.855 0.094  0.049 0.379 1.755 2.107 6.569 0.090 1.826 0.101  0.020 0.377 1.874 2.014 6.567 0.103 1.797 0.082  0.039 0.357 1.859 2.001 6.601 0.092 1.827 0.082  0.005 0.391 1.800 2.112 6.539 0.118 1.802 0.061  0.086 0.341 1.895 1.887 6.722 0.083 1.803 0.082  0.054 0.393 1.821 2.111 6.527 0.103 1.803 0.050  Table II-D  0.000 0.065 2.782 1.985 23.985  0.000 0.082 3.024 1.931 23.931  0.009 0.061 2.975 2.000 24.000  0.000 0.087 2.752 1.970 23.970  0.000 0.082 2.602 1.951 23.951  0.001 0.091 2.678 1.980 23.980  0.004 0.087 2.631 1.961 23.961  0.000 0.090 2.684 1.995 23.995  0.002 0.096 2.550 1.914 23.914  0.009 0.098 2.697 1.946 23.946  Cation Sum Anion Sum  15.529 24.000  15.565 24.000  15.603 24.000  15.588 24.000  15.511 24.000  15.584 24.000  15.539 24.000  15.598 24.000  15.463 24.000  15.611 24.000  Sample  ' (..,.)  Amphibole/Plagioclase Microprobe Data  CR3+ MN2+ FE2+ H+ 02-  F16-15  F16-16  F16-17  F16-18  F16-19  F16-20  F16-21  F16-22  F16-23  F16-24  F NA2O MGO AL203 S102 K2O CAO 1102 CR203 MNO FEO H2O * 0=F  0.06 1.17 8.11 11.10 43.06 0.46 10.96 0.64 0.02 0.64 20.24 1.92 -0.03  0.26 1.19 8.34 10.55 43.47 0.57 10.91 0.56 0.05 0.66 20.38 1.83 -0.11  0.12 1.28 7.66 11.64 42.62 0.50 11.17 0.85 0.00 0.67 20.54 1.90 -0.05  0.22 1.21 7.96 10.96 42.47 0.58 10.77 0.79 0.00 0.73 20.88 1.83 -0.09  0.14 1.09 8.75 10.00 44.33 0.40 10.72 0.55 0.01 0.51 20.14 1.89 -0.06  0.24 1.26 7.58 11.58 42.76 0.56 10.95 0.90 0.14 0.71 19.97 1.83 -0.10  0.19 1.22 7.62 11.61 43.02 0.50 11.02 0.78 0.00 0.66 20.12 1.86 -0.08  0.13 1.20 7.78 11.73 43.47 0.44 11.07 0.72 0.03 0.58 19.91 1.90 -0.05  0.05 1.29 7.44 12.34 42.12 0.60 10.86 0.82 0.16 0.66 20.50 1.93 -0.02  0.15 1.33 7.21 12.62 41.00 0.59 10.76 0.65 0.00 0.70 20.96 1.85 -0.06  TOTAL  98.35  98.66  98.90  98.31  98.47  98.38  98.52  98.91  98.74  97.76  FNA+ MG2+ AL3+ S14+ K+ CA2+  0.029 0.349 1.861 2.013 6.626 0.090 1.807  0.126 0.354 1.910 1.910 6.677 0.112 1.796  0.058 0.381 1.753 2.106 6.544 0.098 1.838  0.108 0.363 1.837 2.000 6.576 0.115 1.787  0.068 0.323 1.996 1.804 6.784 0.078 1.758  0.117 0.376 1.739 2.101 6.582 0.110 1.806  0.092 0.363 1.744 2.101 6.606 0.098 1.813  0.063 0.355 1.768 2.108 6.628 0.086 1.809  0.024 0.385 1.706 2.237 6.478 0.118 1.790  0.074 0.402 1.678 2.322 6.400 0.117 1.800  Table II-D  Amphibole/Plagioclase Microprobe Data  114+ CR3+ MN2+ FE2+ H+ 02-  0.074 0.002 0.083 2.605 1.971 23.971  0.065 0.006 0.086 2.618 1.874 23.874  0.098 0.000 0.087 2.638 1.942 23.942  0.092 0.000 0.096 2.704 1.892 23.892  0.063 0.001 0.066 2.577 1.932 23.932  0.104 0.017 0.093 2.571 1.883 23.883  0.090 0.000 0.086 2.584 1.908 23.908  0.083 0.004 0.075 2.539 1.937 23.937  0.095 0.019 0.086 2.637 1.976 23.976  0.076 0.000 0.093 2.736 1.926 23.926  Cation Sum Anion Sum  15.511 24.000  15.533 24.000  15.544 24.000  15.570 24.000  15.451 24.000  15.498 24.000  15.484 24.000  15.454 24.000  15.550 24.000  15.623 24.000  Sample  F16-25  F16-26  F16-27  MC8-1  MC8-2  MC8-3  MC8-4  MC8-5  MC8-6  MC8-7  F NA2O MGO AL203 S102 K2O CAO 1102 CR203 MNO FEO H2O * 0=F  0.17 1.24 7.50 11.77 41.90 0.62 11.11 0.79 0.02 0.66 20.71 1.85 -0.07  0.12 1.18 7.99 11.13 43.15 0.57 11.23 0.78 0.02 0.55 20.41 1.90 -0.05  0.17 1.26 6.86 11.83 41.59 0.47 10.39 0.86 0.00 0.47 22.71 1.84 -0.07  0.00 0.87 11.64 7.85 45.68 0.76 11.87 0.79 0.02 0.46 16.86 1.99 0.00  0.12 0.85 11.97 8.03 45.78 0.76 12.07 0.81 0.01 0.45 16.71 1.94 -0.05  0.14 0.91 11.43 8.22 44.50 0.75 11.84 0.83 0.02 0.40 17.07 1.90 -0.06  0.27 0.97 11.45 8.39 44.89 0.81 11.70 0.87 0.00 0.39 17.29 1.85 -0.11  0.20 0.87 11.55 8.20 45.00 0.73 12.12 0.64 0.00 0.43 16.90 1.88 -0.08  0.20 0.94 11.98 7.97 45.47 0.73 12.00 0.83 0.04 0.49 16.83 1.90 -0.08  0.07 0.71 12.11 7.32 46.64 0.57 12.09 0.58 0.00 0.41 16.71 1.97 -0.03  TOTAL  98.27  98.98  98.38  98.79  99.45  97.95  98.77  98.44  99.29  99.15  FNA+ MG2+ AL3+ _^S14+ `-''^K+ 4=.  0.083 0.373 1.733 2.150 6.495 0.123  0.058 0.350 1.824 2.009 6.609 0.111  0.084 0.381 1.593 2.172 6.478 0.093  0.000 0.255 2.620 1.397 6.897 0.146  0.057 0.247 2.675 1.419 6.863 0.145  0.068 0.270 2.604 1.480 6.800 0.146  0.129 0.285 2.587 1.498 6.803 0.157  0.096 0.256 2.615 1.467 6.833 0.141  0.095 0.274 2.686 1.413 6.839 0.140  0.033 0.206 2.705 1.293 6.990 0.109  Table II-D  Amphibole/Plagioclase Microprobe Data  CA2+ 114+ CR3+ MN2+ FE2+ H+ 02-  1.845 0.092 0.002 0.087 2.685 1.917 23.917  1.843 0.090 0.002 0.071 2.614 1.942 23.942  1.734 0.101 0.000 0.062 2.958 1.916 23.916  1.920 0.090 0.002 0.059 2.129 2.000 24.000  1.939 0.091 0.001 0.057 2.095 1.943 23.943  1.939 0.095 0.002 0.052 2.182 1.932 23.932  1.900 0.099 0.000 0.050 2.191 1.871 23.871  1.972 0.073 0.000 0.055 2.146 1.904 23.904  1.934 0.094 0.005 0.062 2.117 1.905 23.905  1.941 0.065 0.000 0.052 2.094 1.967 23.967  Cation Sum Anion Sum  15.584 24.000  15.526 24.000  15.572 24.000  15.514 24.000  15.532 24.000  15.571 24.000  15.570 24.000  15.559 24.000  15.565 24.000  15.456 24.000  Sample  MC8-8  MC8-9  MC8-10  MC8-11  MC8-12  MC8-13  MC8-14  MC8-15  MC8-16  MC8-17  F NA2O MGO AL203 S102 K2O CAO TIO2 CR203 MNO FEO H2O * 0=F  0.21 0.72 12.35 7.28 46.58 0.56 12.17 0.77 0.03 0.46 16.16 1.90 -0.09  0.13 0.79 12.31 7.60 46.11 0.57 12.20 0.72 0.02 0.32 16.26 1.94 -0.05  0.14 0.82 11.95 8.00 45.78 0.63 11.94 0.73 0.01 0.44 16.49 1.93 -0.06  0.16 0.93 11.27 8.67 44.98 0.73 11.92 0.67 0.00 0.44 17.15 1.90 -0.07  0.08 0.80 11.99 7.87 45.63 0.66 12.16 0.77 0.01 0.41 16.16 1.95 -0.03  0.19 0.85 11.74 8.28 45.20 0.78 12.09 0.82 0.01 0.45 16.52 1.89 -0.08  0.14 0.86 11.66 8.15 45.49 0.69 12.03 0.71 0.02 0.37 16.83 1.92 -0.06  0.06 0.85 11.55 8.39 45.33 0.74 12.03 0.82 0.03 0.44 17.18 1.96 -0.03  0.11 0.90 11.73 8.30 44.96 0.79 11.96 0.93 0.00 0.39 17.02 1.93 -0.05  0.00 0.01 0.04 23.77 37.53 0.00 23.08 0.07 0.02 0.12 11.57 1.98 0.00  TOTAL  99.10  98.91  98.80  98.76  98.45  98.74  98.81  99.36  98.98  98.19  FNA+ MG2+ AL3+ S14+  0.099 0.209 2.756 1.284 6.973  0.062 0.230 2.755 1.345 6.923  0.067 0.239 2.682 1.419 6.892  0.077 0.273 2.543 1.547 6.808  0.038 0.234 2.699 1.401 6.891  0.091 0.249 2.644 1.474 6.828  0.067 0.252 2.623 1.449 6.865  0.029 0.248 2.590 1.487 6.819  0.053 0.264 2.642 1.478 6.793  0.000 0.003 0.009 4.245 5.687  Table II-D K+ CA2+ T14+ CR3+ MN2+ FE2+ H+ 02Cation Sum Anion Sum Sample  -  Amphibole/Plagioclase Microprobe Data 0.141 0.121 0.109 0.107 1.933 1.926 1.952 1.963 0.076 0.083 0.087 0.081 0.000 0.002 0.001 0.004 0.056 0.041 0.056 0.058 2.171 2.076 2.042 2.023 1.923 1.933 1.901 1.938 23.938 23.933 23.923 23.901 15.454 24.000 MC8-18  15.491 24.000 MC8-19  15.495 24.000 MC8-20  15.549 24.000 MC8-21  0.127 1.968 0.087 0.001 0.052 2.041 1.962 23.962  0.150 1.957 0.093 0.001 0.058 2.087 1.909 23.909  0.133 1.945 0.081 0.002 0.047 2.124 1.933 23.933  0.142 1.939 0.093 0.004 0.056 2.161 1.971 23.971  0.152 1.936 0.106 0.000 0.050 2.150 1.947 23.947  0.000 3.747 0.008 0.002 0.015 1.466 2.000 24.000  15.502 24.000  15.541 24.000  15.521 24.000  15.538 24.000  15.571 24.000  15.183 24.000  MC8-22  MC8-23  MC8-24  MC8-25  MC8-26  PL28-1  F NA2O MGO AL203 S102 K2O CAO TIO2 CR203 MNO FEO H2O * 0=F  0.11 0.60 13.29 5.42 49.04 0.45 12.25 0.50 0.00 0.37 15.85 1.98 -0.05  0.00 0.78 11.95 7.76 45.61 0.67 12.03 0.73 0.01 0.38 16.65 1.98 0.00  0.10 0.80 11.23 8.79 44.77 0.73 12.01 0.70 0.02 0.45 17.04 1.93 -0.04  0.18 0.81 11.86 7.98 45.33 0.70 12.10 0.75 0.02 0.44 16.80 1.90 -0.08  0.19 0.78 11.99 7.87 46.01 0.64 11.89 0.74 0.00 0.41 16.66 1.91 -0.08  0.12 0.76 12.87 6.91 47.26 0.51 12.20 0.67 0.01 0.45 16.08 1.96 -0.05  0.08 0.82 11.61 8.57 45.16 0.75 11.98 0.75 0.00 0.36 16.63 1.95 -0.03  0.17 0.92 11.86 7.74 46.15 0.72 11.83 0.80 0.02 0.46 16.82 1.92 -0.07  0.21 0.86 11.69 8.31 45.87 0.74 11.96 0.75 0.02 0.50 16.68 1.90 -0.09  0.00 0.61 10.69 7.42 47.39 0.43 12.06 0.53 0.00 0.54 17.51 2.00 0.00  TOTAL  99.81  98.55  98.53  98.79  99.01  99.75  98.62  99.34  99.40  99.18  FNA+ MG2+ AL3+  0.051 0.172 2.925 0.943  0.000 0.229 2.692 1.382  0.048 0.235 2.539 1.571  0.086 0.237 2.671 1.421  0.090 0.227 2.685 1.393  0.056 0.219 2.849 1.209  0.038 0.240 2.615 1.526  0.081 0.267 2.651 1.368  0.100 0.250 2.611 1.467  0.000 0.177 2.388 1.310  Table II-D  Amphibole/Plagioclase Microprobe Data  SI4+ K+ CA2+ TI4+ CR3+ MN2+ FE2+ H+ 02-  7.240^6.893^6.791^6.849 0.135 0.141 0.129 0.085 1.952 1.959 1.948 1.938 0.080 0.085 0.083 0.056 0.002 0.002 0.001 0.000 0.056 0.058 0.049 0.046 2.161 2.123 2.104 1.957 1.952 1.914 2.000 1.949 23.952 23.914 24.000 23.949  6.912 0.123 1.914 0.084 0.000 0.052 2.093 1.910 23.910  7.017 0.097 1.941 0.075 0.001 0.057 1.997 1.944 23.944  6.823 0.145 1.939 0.085 0.000 0.046 2.101 1.962 23.962  6.921 0.138 1.901 0.090 0.002 0.058 2.109 1.919 23.919  6.873 0.141 1.920 0.085 0.002 0.063 2.090 1.900 23.900  7.100 0.082 1.936 0.060 0.000 0.069 2.194 2.000 24.000  Cation Sum Anion Sum  15.361 24.000  15.540 24.000  15.483 24.000  15.461 24.000  15.521 24.000  15.506 24.000  15.503 24.000  15.315 24.000  Sample  PL28-2  15.511 24.000 PL28-3  15.531 24.000 PL28-4  PL28-5  PL28-6  PL28-7  PL28-8  PL28-9  P28-10  P28-11  F NA2O MGO AL203 S102 K2O CAO 1102 CR203 MNO FEO H2O * 0=F  0.10 0.78 9.72 9.06 45.94 0.61 12.03 0.68 0.03 0.57 18.18 1.95 -0.04  0.04 0.79 9.68 9.72 45.17 0.79 11.95 0.82 0.04 0.53 17.32 1.97 -0.02  0.00 0.69 10.77 9.01 45.71 0.63 11.86 0.77 0.01 0.59 16.80 1.99 0.00  0.11 0.77 9.24 10.39 45.13 0.60 11.92 0.60 0.01 0.56 18.13 1.94 -0.05  0.22 0.70 10.09 8.69 45.97 0.52 12.09 0.40 0.01 0.51 17.49 1.88 -0.09  0.20 0.83 8.69 10.64 44.95 0.68 11.88 0.32 0.01 0.60 18.98 1.89 -0.08  0.07 0.72 10.09 8.26 47.08 0.45 11.92 0.30 0.01 0.67 17.77 1.97 -0.03  0.21 0.81 9.38 9.86 45.70 0.56 11.77 0.29 0.00 0.59 18.46 1.89 -0.09  0.05 0.68 9.34 9.28 45.42 0.71 12.01 0.87 0.00 0.47 18.27 1.96 -0.02  0.14 0.71 9.55 9.37 45.80 0.72 11.95 0.75 0.00 0.57 17.82 1.93 -0.06  TOTAL  99.61  98.80  98.83  99.35  98.47  99.59  99.28  99.44  99.04  99.25  FNA+ MG2+  0.047 0.227 2.176  0.019 0.231 2.180  0.000 0.201 2.415  0.052 0.225 2.073  0.105 0.205 2.276  0.095 0.243 1.954  0.033 0.209 2.255  0.100 0.236 2.103  0.024 0.199 2.105  0.067 0.207 2.142  Table II-D AL3+ S14+ K+ CA2+ T14+ CR3+ MN2+ FE2+ H+ 02Cation Sum Anion Sum Sample  Amphibole/Plagioclase Microprobe Data 1.843 1.597 1.731 1.603 6.791 6.876 6.899 6.824 0.115 0.121 0.152 0.117 1.922 1.911 1.936 1.934 0.087 0.068 0.093 0.077 0.001 0.005 0.001 0.004 0.075 0.071 0.072 0.068 2.281 2.188 2.113 2.283 1.948 1.981 2.000 1.953 23.948 23.953 23.981 24.000 15.393 24.000 P28-12  15.407 24.000 P28-13  15.399 24.000 P28-14  15.389 24.000 P28-15  1.550 6.957 0.100 1.960 0.046 0.001 0.065 2.214 1.895 23.895  1.891 6.779 0.131 1.920 0.036 0.001 0.077 2.394 1.905 23.905  1.459 7.057 0.086 1.914 0.034 0.001 0.085 2.227 1.967 23.967  1.748 6.873 0.107 1.896 0.033 0.000 0.075 2.322 1.900 23.900  1.653 6.867 0.137 1.945 0.099 0.000 0.060 2.310 1.976 23.976  1.662 6.891 0.138 1.926 0.085 0.000 0.073 2.242 1.933 23.933  15.375 24.000  15.425 24.000  15.327 24.000  15.393 24.000  15.376 24.000  15.366 24.000  P28-16  P28-17  P28-18  P28-19  P28-20  P28-21  F NA2O MGO AL203 S102 K2O CAO T102 CR203 MNO FEO H2O * 0=F  0.07 0.66 10.42 8.19 46.58 0.63 11.87 0.83 0.00 0.54 17.59 1.97 -0.03  0.06 0.61 10.62 7.81 47.10 0.55 12.01 0.68 0.00 0.55 16.98 1.97 -0.03  0.21 0.85 7.46 11.75 43.45 0.79 11.69 0.31 0.02 0.48 19.81 1.86 -0.09  0.08 0.69 9.41 8.56 46.59 0.54 11.95 0.29 0.02 0.58 18.58 1.95 -0.03  0.08 0.93 4.36 17.38 40.25 0.87 11.69 0.03 0.00 0.50 20.72 1.91 -0.03  0.10 0.97 7.05 12.54 42.60 0.77 11.73 0.40 0.00 0.52 19.76 1.90 -0.04  0.24 0.91 7.31 11.97 43.20 0.76 11.68 0.34 0.01 0.52 20.05 1.84 -0.10  0.17 0.72 8.59 9.34 45.75 0.59 11.90 0.32 0.00 0.56 19.06 1.89 -0.07  0.15 0.94 5.54 15.51 40.98 0.89 11.81 0.17 0.00 0.58 20.55 1.88 -0.06  0.17 0.88 6.98 12.55 42.55 0.95 11.80 0.43 0.01 0.60 20.64 1.88 -0.07  TOTAL  99.32  98.92  98.59  99.21  98.69  98.30  98.73  98.82  98.94  99.37  FNA+  0.033 0.192  0.028 0.177  0.102 0.253  0.038 0.202  0.039 0.277  0.049 0.289  0.116 0.270  0.082 0.212  0.073 0.280  0.082 0.261  Table II-D  2.330 1.448 6.986 0.121 1.908 0.094 0.000 0.069 2.206 1.967 23.967  2.375 1.381 7.065 0.105 1.930 0.077 0.000 0.070 2.130 1.972 23.972  1.704 2.122 6.657 0.154 1.919 0.036 0.002 0.062 2.538 1.898 23.898  2.114 1.520 7.020 0.104 1.929 0.033 0.002 0.074 2.341 1.962 23.962  1.000 3.151 6.192 0.171 1.927 0.003 0.000 0.065 2.666 1.961 23.961  1.617 2.275 6.556 0.151 1.934 0.046 0.000 0.068 2.543 1.951 23.951  1.670 2.162 6.621 0.149 1.918 0.039 0.001 0.068 2.570 1.884 23.884  1.944 1.671 6.944 0.114 1.935 0.037 0.000 0.072 2.419 1.918 23.918  1.269 2.808 6.296 0.174 1.944 0.020 0.000 0.075 2.640 1.927 23.927  1.593 2.265 6.515 0.186 1.936 0.050 0.001 0.078 2.643 1.918 23.918  Cation Sum Anion Sum  15.352 24.000  15.309 24.000  15.448 24.000  15.339 24.000  15.453 24.000  15.480 24.000  15.468 24.000  15.347 24.000  15.507 24.000  15.526 24.000  Sample  ■.0  Amphibole/Plagioclase Microprobe Data  MG2+ AL3+ S14+ K+ CA2+ T14+ CR3+ MN2+ FE2+ H+ 02-  PL9-2  PL9-1  PL9-3  PL9-4  PL9-5  PL9-6  PL9-7  PL9-8  PL9-9  PL9-10  F NA2O MGO AL203 S102 K2O CAO T102 CR203 MNO FEO H2O * 0=F  0.22 0.88 13.51 8.54 47.63 0.29 12.15 0.28 0.00 0.47 13.45 1.94 -0.09  0.12 0.95 13.42 8.35 47.33 0.29 12.01 0.29 0.02 0.50 13.37 1.97 -0.05  0.12 1.05 12.20 10.09 45.40 0.50 12.01 0.44 0.00 0.52 14.27 1.95 -0.05  0.21 0.88 13.20 9.01 46.43 0.46 12.26 0.40 0.00 0.51 13.59 1.92 -0.09  0.16 0.96 12.38 9.59 45.91 0.47 12.09 0.40 0.14 0.46 14.47 1.94 -0.07  0.02 0.93 12.06 10.46 44.90 0.50 12.02 0.42 0.07 0.55 14.97 2.00 -0.01  0.22 1.33 10.42 12.38 43.18 0.50 11.63 0.33 0.03 0.50 15.90 1.88 -0.09  0.14 0.82 12.22 9.44 45.15 0.76 12.11 0.37 0.03 0.46 15.37 1.93 -0.06  0.32 1.02 11.81 10.43 44.66 0.59 11.88 0.44 0.02 0.61 15.35 1.85 -0.13  0.31 0.96 12.93 9.07 46.46 0.40 11.82 0.33 0.00 0.48 14.21 1.87 -0.13  TOTAL  99.26  98.57  98.50  98.78  98.90  98.89  98.21  98.74  98.84  98.71  F-  0.102  0.056  0.057  0.098  0.075  0.009  0.105  0.066  0.152  0.146  Table II-D NA+ MG2+ AL3+ S14+ K+ CA2+ T14+ CR3+ MN2+ FE2+ H+ 02Cation Sum Anion Sum Sample  Amphibole/Plagioclase Microprobe Data 0.253 0.304 0.272 0.251 2.917 2.715 2.960 2.958 1.574 1.775 1.456 1.478 6.883 7.002 6.778 6.995 0.087 0.095 0.055 0.054 1.947 1.921 1.904 1.912 0.045 0.049 0.032 0.031 0.000 0.000 0.002 0.000 0.064 0.063 0.066 0.058 1.685 1.782 1.654 1.652 1.943 1.902 1.944 1.898 23.943 23.902 23.944 23.898  0.277 2.744 1.681 6.827 0.089 1.926 0.045 0.016 0.058 1.799 1.925 23.925  0.269 2.684 1.840 6.703 0.095 1.923 0.047 0.008 0.070 1.869 1.991 23.991  0.390 2.349 2.206 6.529 0.096 1.884 0.038 0.004 0.064 2.011 1.895 23.895  0.239 2.733 1.669 6.774 0.145 1.947 0.042 0.004 0.058 1.929 1.934 23.934  0.296 2.638 1.842 6.692 0.113 1.907 0.050 0.002 0.077 1.923 1.848 23.848  0.276 2.863 1.588 6.900 0.076 1.881 0.037 0.000 0.060 1.765 1.854 23.854  15.455 24.000  15.463 24.000  15.508 24.000  15.571 24.000  15.540 24.000  15.541 24.000  15.445 24.000  15.388 24.000 PL9-11  15.400 24.000 PL9-12  15.485 24.000 PL9-13  PL9-14  PL9-15  PL9-16  PL9-17  PL9-18  PL9-19  PL9-20  NA2O MGO AL203 S102 K2O CAO T102 CR203 MNO FEO H2O * 0=F  0.19 0.78 14.03 8.14 47.19 0.33 12.05 0.29 0.03 0.48 12.79 1.93 -0.08  0.06 1.10 11.00 11.18 43.01 0.46 11.63 0.32 0.00 0.43 14.29 1.91 -0.03  0.24 0.99 12.48 10.03 45.37 0.51 12.11 0.37 0.00 0.49 14.55 1.90 -0.10  0.18 0.83 13.36 8.62 47.01 0.43 12.20 0.31 0.05 0.54 13.23 1.94 -0.08  0.26 0.87 12.99 9.15 46.37 0.40 12.05 0.56 0.09 0.53 13.63 1.90 -0.11  0.28 1.08 12.33 10.40 45.31 0.43 12.15 0.35 0.04 0.55 14.42 1.89 -0.12  0.23 0.98 12.09 10.36 44.87 0.54 11.91 0.40 0.03 0.47 14.22 1.89 -0.10  0.07 0.92 12.98 9.18 45.97 0.45 12.18 0.33 0.06 0.39 13.84 1.98 -0.03  0.19 1.08 12.01 11.06 44.60 0.47 11.98 0.32 0.00 0.52 15.10 1.92 -0.08  0.15 0.84 13.28 8.76 46.67 0.41 12.17 0.36 0.04 0.47 13.74 1.95 -0.06  TOTAL  98.15  95.37  98.94  98.62  98.69  99.11  97.89  98.32  99.17  98.78  F  Table II-D  0.089 0.224 3.101 1.422 6.996 0.062 1.914 0.032 0.004 0.060 1.586 1.911 23.911  0.029 0.330 2.535 2.037 6.648 0.091 1.926 0.037 0.000 0.056 1.847 1.971 23.971  0.113 0.286 2.770 1.760 6.755 0.097 1.932 0.041 0.000 0.062 1.812 1.887 23.887  0.084 0.238 2.948 1.504 6.959 0.081 1.935 0.035 0.006 0.068 1.638 1.916 23.916  0.122 0.250 2.872 1.599 6.877 0.076 1.915 0.062 0.011 0.067 1.690 1.878 23.878  0.132 0.311 2.731 1.821 6.731 0.081 1.934 0.039 0.005 0.069 1.791 1.868 23.868  0.109 0.286 2.708 1.835 6.742 0.104 1.918 0.045 0.004 0.060 1.787 1.891 23.891  0.033 0.266 2.886 1.614 6.856 0.086 1.946 0.037 0.007 0.049 1.726 1.967 23.967  0.090 0.312 2.667 1.942 6.644 0.089 1.912 0.036 0.000 0.066 1.881 1.910 23.910  0.070 0.241 2.934 1.530 6.916 0.078 1.932 0.040 0.005 0.059 1.703 1.930 23.930  Cation Sum Anion Sum  15.402 24.000  15.507 24.000  15.515 24.000  15.411 24.000  15.419 24.000  15.513 24.000  15.488 24.000  15.473 24.000  15.550 24.000  15.436 24.000  Sample  _  Amphibole/Plagioclase Microprobe Data  FNA+ MG2+ AL3+ SI4+ K+ CA2+ T14+ CR3+ MN2+ FE2+ H+ 02-  PL9-21  PL9-22  PL9-23  PL9-24  PL9-25  PL9-26  F NA2O MGO AL203 SIO2 K2O CAO TIO2 CR203 MNO FEO H2O * 0=F  0.28 1.01 13.16 9.11 46.68 0.39 11.97 0.31 0.04 0.40 13.78 1.89 -0.12  0.10 0.96 12.62 9.54 45.10 0.46 11.86 0.36 0.20 0.47 14.37 1.95 -0.04  0.16 0.97 13.20 8.92 46.54 0.31 12.20 0.31 0.05 0.47 13.59 1.95 -0.07  0.19 0.84 13.03 9.28 46.43 0.42 12.21 0.31 0.00 0.50 14.23 1.94 -0.08  0.12 0.98 12.64 9.88 45.74 0.40 11.98 0.30 0.02 0.44 14.44 1.96 -0.05  0.14 0.91 13.48 8.46 47.45 0.57 11.94 0.32 0.13 0.46 13.22 1.97 -0.06  TOTAL  98.91  97.95  98.60  99.30  98.85  98.99  Table II-D  Amphibole/Plagioclase Microprobe Data  FNA+ MG2+ AL3+ S14+ K+ CA2+ T14+ CR3+ MN2+ FE2+ H+ 02-  0.131 0.290 2.902 1.588 6.904 0.074 1.897 0.034 0.005 0.050 1.704 1.869 23.869  0.048 0.280 2.828 1.690 6.780 0.088 1.910 0.041 0.024 0.060 1.806 1.952 23.952  0.075 0.279 2.919 1.560 6.905 0.059 1.939 0.035 0.006 0.059 1.686 1.925 23.925  0.089 0.241 2.870 1.616 6.861 0.079 1.933 0.034 0.000 0.063 1.759 1.911 23.911  0.056 0.282 2.801 1.731 6.798 0.076 1.908 0.034 0.002 0.055 1.795 1.944 23.944  0.065 0.260 2.961 1.469 6.993 0.107 1.885 0.035 0.015 0.057 1.629 1.935 23.935  Cation Sum Anion Sum  15.447 24.000  15.507 24.000  15.447 24.000  15.456 24.000  15.481 24.000  15.413 24.000  FELDSPAR Sample  PL2-2  PL2-1  PL2-3  PL2-4  PL2-5  PL2-6  PL2-7  PL2-8  PL2-9  PL21-0  NA2O MGO AL203 S102 K2O CAO MNO FEO  6.73 0.00 26.47 58.46 0.06 8.37 0.00 0.15  6.61 0.01 26.17 58.96 0.08 8.38 0.00 0.06  6.74 0.01 25.95 59.89 0.04 7.78 0.00 0.11  7.10 0.00 25.58 60.19 0.07 7.51 0.00 0.15  7.91 0.00 24.58 61.95 0.04 5.98 0.01 0.23  6.78 0.02 26.04 59.41 0.06 7.80 0.01 0.03  7.11 0.00 25.79 60.27 0.07 7.53 0.00 0.10  6.92 0.00 25.83 59.88 0.06 7.58 0.01 0.01  6.98 0.01 25.60 59.45 0.12 7.29 0.00 0.10  6.87 0.00 25.85 59.49 0.08 7.87 0.00 0.04  TOTAL  100.24  100.27  100.52  100.60  100.70  100.15  100.87  100.29  99.55  100.20  Table II-D NA+ MG2+ AL3+ S14+ K+ CA2+ MN2+ FE2+  0.582 0.000 1.391 2.607 0.003 0.400 0.000 0.006  0.571 0.001 1.373 2.625 0.005 0.400 0.000 0.002  0.579 0.001 1.354 2.652 0.002 0.369 0.000 0.004  0.609 0.000 1.335 2.665 0.004 0.356 0.000 0.006  0.675 0.000 1.276 2.728 0.002 0.282 0.000 0.008  0.585 0.001 1.365 2.642 0.003 0.372 0.000 0.001  0.609 0.000 1.342 2.661 0.004 0.356 0.000 0.004  0.595 0.000 1.351 2.657 0.003 0.360 0.000 0.000  0.605 0.001 1.349 2.658 0.007 0.349 0.000 0.004  0.592 0.000 1.355 2.646 0.005 0.375 0.000 0.001  Cation Sum Anion Sum  4.990 8.000  4.976 8.000  4.961 8.000  4.975 8.000  4.973 8.000  4.969 8.000  4.975 8.000  4.967 8.000  4.973 8.000  4.975 8.000  Sample  _ w ° w  Amphibole/Plagioclase Microprobe Data  PL2-11  PL2-12  PL2-13  PL2-14  PL2-15  PL2-16  PL2-17  PL2-18  PL2-19  PL2-20  NA2O MGO AL203 S102 K2O CAO MNO FEO  6.93 0.00 25.65 59.59 0.05 7.48 0.00 0.02  6.86 0.00 25.73 59.91 0.07 7.86 0.00 0.10  6.82 0.00 25.77 59.94 0.07 7.77 0.00 0.12  6.75 0.00 25.60 59.83 0.12 7.69 0.00 0.08  7.31 0.00 25.00 60.71 0.15 6.76 0.01 0.05  7.00 0.00 25.61 60.40 0.10 7.44 0.01 0.12  6.85 0.00 25.62 59.75 0.09 7.66 0.03 0.18  7.09 0.00 25.41 60.47 0.03 7.26 0.01 0.12  7.01 0.00 25.76 59.72 0.04 7.50 0.03 0.14  6.83 0.00 25.83 59.82 0.04 7.72 0.00 0.11  TOTAL  99.72  100.53  100.49  100.07  99.99  100.68  100.18  100.39  100.20  100.35  NA+ MG2+ AL3+ S14+ K+ CA2+ MN2+  0.599 0.000 1.349 2.659 0.003 0.358 0.000 0.001  0.589 0.000 1.344 2.655 0.004 0.373 0.000 0.004  0.586 0.000 1.346 2.656 0.004 0.369 0.000 0.004  0.582 0.000 1.342 2.661 0.007 0.367 0.000 0.003  0.630 0.000 1.309 2.697 0.009 0.322 0.000 0.002  0.600 0.000 1.334 2.670 0.006 0.352 0.000 0.004  0.591 0.000 1.343 2.657 0.005 0.365 0.001 0.007  0.609 0.000 1.326 2.678 0.002 0.344 0.000 0.004  0.604 0.000 1.349 2.655 0.002 0.357 0.001 0.005  0.588 0.000 1.351 2.654 0.002 0.367 0.000 0.004  ^  Table II-D  Amphibole/Plagioclase Microprobe Data  ^4.968^4.970^4.966^4.962 Cation Sum 8.000^8.000^8.000^8.000 Anion Sum  Sample  PL2-21  PL2-22  PL2-23  PL2-24  4.968 8.000 PL2-25  4.966 8.000 PL2-26  4.969 8.000 PL2-27  4.964 8.000 HH2-1  4.974 8.000 HH2-2  4.966 8.000 HH2-3  NA2O MGO AL203 S102 K2O CAO MNO FEO  6.75 0.00 26.07 59.54 0.10 7.89 0.00 0.07  7.23 0.00 25.23 60.57 0.06 7.13 0.00 0.11  7.04 0.00 25.70 60.28 0.06 7.48 0.01 0.04  7.47 0.00 24.91 60.86 0.05 6.69 0.03 0.07  7.05 0.00 25.56 60.22 0.05 7.39 0.00 0.04  7.12 0.00 25.55 59.75 0.07 7.47 0.00 0.09  7.07 0.01 25.53 60.68 0.04 7.41 0.00 0.00  6.66 0.00 25.96 59.08 0.07 8.04 0.01 0.17  6.70 0.00 26.05 59.45 0.06 7.92 0.03 0.06  6.81 0.00 25.74 59.14 0.08 7.78 0.00 0.21  TOTAL  100.42  100.33  100.61  100.08  100.31  100.05  100.74  99.99  100.27  99.76  NA+ MG2+ AL3+ S14+ K+ CA2+ MN2+ FE2+  0.581 0.000 1.363 2.642 0.006 0.375 0.000 0.003  0.621 0.000 1.318 2.684 0.003 0.339 0.000 0.004  0.604 0.000 1.339 2.666 0.003 0.354 0.000 0.001  0.643 0.000 1.303 2.701 0.003 0.318 0.001 0.003  0.606 0.000 1.336 2.670 0.003 0.351 0.000 0.001  0.615 0.000 1.341 2.660 0.004 0.356 0.000 0.003  0.605 0.001 1.327 2.677 0.002 0.350 0.000 0.000  0.576 0.000 1.365 2.636 0.004 0.384 0.000 0.006  0.577 0.000 1.364 2.642 0.003 0.377 0.001 0.002  0.590 0.000 1.356 2.644 0.005 0.373 0.000 0.008  Cation Sum Anion Sum  4.969 8.000  4.969 8.000  4.968 8.000  4.971 8.000  4.967 8.000  4.979 8.000  4.963 8.000  4.972 8.000  4.967 8.000  4.975 8.000  Sample NA2O MGO AL203  HH2-4 6.86 0.00 25.56  HH2-5 7.00 0.00 25.33  HH2-6 6.96 0.00 25.49  HH2-7 6.93 0.00 25.82  HH2-8 6.67 0.00 26.05  HH2-9 7.13 0.00 25.96  HH2-10 7.20 0.00 25.18  HH2-11 6.79 0.00 25.82  HH2-12 6.62 0.01 26.14  HH2-13 7.29 0.00 25.29  Table II-D  Amphibole/Plagioclase Microprobe Data 59.80 0.08 7.63 0.00 0.13  60.42 0.05 7.34 0.00 0.13  59.88 0.04 7.66 0.04 0.17  59.82 0.10 7.92 0.02 0.15  59.16 0.08 8.14 0.00 0.19  60.05 0.04 7.71 0.03 0.03  60.64 0.12 7.07 0.00 0.06  59.23 0.11 7.85 0.00 0.10  59.18 0.05 8.00 0.01 0.15  60.86 0.04 7.09 0.01 0.18  TOTAL  100.06  100.27  100.24  100.76  100.29  100.95  100.27  99.90  100.16  100.76  NA+ MG2+ AL3+ S14+ K+ CA2+ MN2+ FE2+  0.592 0.000 1.341 2.661 0.005 0.364 0.000 0.005  0.602 0.000 1.324 2.679 0.003 0.349 0.000 0.005  0.600 0.000 1.335 2.662 0.002 0.365 0.002 0.006  0.595 0.000 1.347 2.648 0.006 0.376 0.001 0.006  0.575 0.000 1.366 2.633 0.005 0.388 0.000 0.007  0.610 0.000 1.350 2.651 0.002 0.365 0.001 0.001  0.619 0.000 1.315 2.688 0.007 0.336 0.000 0.002  0.588 0.000 1.358 2.643 0.006 0.375 0.000 0.004  0.571 0.001 1.371 2.634 0.003 0.382 0.000 0.006  0.624 0.000 1.315 2.686 0.002 0.335 0.000 0.007  Cation Sum Anion Sum  4.967 8.000  4.961 8.000  4.972 8.000  4.978 8.000  4.974 8.000  4.980 8.000  4.967 8.000  4.974 8.000  4.967 8.000  4.969 8.000  S102 K2O CAO MNO FEO  Sample  HH2-15  HH2-16  HH2-17  HH2-18  HH2-19  HH2-20  HH2-21  HH2-22  HH2-23  HH2-24  NA2O MGO AL2O3 S102 K2O CAO MNO FEO  6.57 0.00 26.33 59.33 0.06 8.14 0.00 0.15  6.85 0.00 25.94 59.47 0.13 7.92 0.03 0.10  6.92 0.01 25.82 59.46 0.04 7.82 0.01 0.18  6.89 0.00 25.64 60.46 0.06 7.80 0.00 0.04  7.16 0.00 25.30 60.45 0.12 7.17 0.01 0.07  6.87 0.01 25.56 59.80 0.10 7.83 0.00 0.01  7.17 0.00 25.17 61.11 0.05 6.99 0.00 0.10  6.77 0.00 26.01 59.38 0.07 7.99 0.01 0.08  6.96 0.00 25.69 59.54 0.04 7.64 0.01 0.08  6.74 0.00 25.02 58.10 0.09 7.39 0.00 0.23  TOTAL  100.58  100.44  100.26  100.89  100.28  100.18  100.59  100.31  99.96  97.57  Table II-D NA+ MG2+ AL3+ S14+ K+ CA2+ MN2+ FE2+ Cation Sum Anion Sum Sample  Amphibole/Plagioclase Microprobe Data 0.589 0.590 0.597 0.565 0.000 0.000 0.000 0.001 1.333 1.354 1.358 1.376 2.641 2.645 2.667 2.630 0.007 0.002 0.003 0.003 0.387 0.377 0.373 0.369 0.000 0.001 0.000 0.000 0.004 0.001 0.006 0.007 4.966 8.000 HH2-25  4.978 8.000 HH2-26  4.978 8.000 HH2-28  4.963 8.000 HH2-29  0.616 0.000 1.322 2.681 0.007 0.341 0.000 0.003  0.592 0.001 1.339 2.659 0.006 0.373 0.000 0.000  0.614 0.000 1.309 2.697 0.003 0.331 0.000 0.004  0.583 0.000 1.363 2.639 0.004 0.381 0.000 0.003  0.601 0.000 1.349 2.653 0.002 0.365 0.000 0.003  0.597 0.000 1.347 2.654 0.005 0.362 0.000 0.009  4.969 8.000  4.970 8.000  4.957 8.000  4.973 8.000  4.974 8.000  4.974 8.000  HH2-30  HH2-31  HH2-32  HH2-33  HH2-34  FC16-1  NA2O MGO AL203 S102 K2O CAO MNO FEO  6.79 0.00 26.07 59.26 0.05 7.92 0.04 0.14  6.95 0.00 25.71 59.62 0.06 7.66 0.04 0.06  7.01 0.00 25.48 60.25 0.05 7.68 0.00 0.21  6.83 0.00 25.90 59.80 0.07 7.68 0.01 0.27  7.27 0.00 25.31 60.61 0.05 7.11 0.00 0.12  6.95 0.00 25.64 59.88 0.10 7.72 0.00 0.11  6.69 0.00 25.95 59.55 0.06 8.21 0.01 0.13  6.75 0.00 26.05 59.14 0.07 7.80 0.00 0.09  6.61 0.00 26.00 59.12 0.08 8.07 0.01 0.12  7.06 0.02 26.07 59.58 0.05 8.15 0.00 0.33  TOTAL  100.27  100.10  100.68  100.56  100.47  100.40  100.60  99.90  100.01  101.26  NA+ MG2+ AL3+ S14+ K+ CA2+ MN2+ FE2+  0.586 0.000 1.367 2.636 0.003 0.377 0.002 0.005  0.600 0.000 1.349 2.653 0.003 0.365 0.002 0.002  0.601 0.000 1.329 2.666 0.003 0.364 0.000 0.008  0.587 0.000 1.353 2.650 0.004 0.365 0.000 0.010  0.624 0.000 1.320 2.682 0.003 0.337 0.000 0.004  0.598 0.000 1.341 2.658 0.006 0.367 0.000 0.004  0.575 0.000 1.356 2.641 0.003 0.390 0.000 0.005  0.584 0.000 1.369 2.638 0.004 0.373 0.000 0.003  0.571 0.000 1.366 2.636 0.005 0.386 0.000 0.004  0.604 0.001 1.357 2.631 0.003 0.386 0.000 0.012  ^  Table II-D  Amphibole/Plagioclase Microprobe Data  ^4.975^4.974^4.971^4.969 Cation Sum 8.000^8.000^8.000^8.000 Anion Sum  Sample  FC16-6  4.974 8.000 FC16-7  4.971 8.000 FC16-8  4.971 8.000 FC16-9  4.969 8.000 F16-10  4.994 8.000 F16-11  NA2O MGO AL203 S102 K2O CAO MNO FEO  6.79 0.00 26.24 59.69 0.04 8.05 0.01 0.28  5.56 0.00 27.96 55.97 0.06 10.30 0.03 0.15  6.61 0.00 26.21 59.04 0.05 8.28 0.00 0.07  5.02 0.00 29.01 55.93 0.03 10.98 0.00 0.36  5.90 0.01 27.39 57.14 0.02 9.83 0.00 0.09  6.74 0.00 26.47 59.22 0.05 8.48 0.00 0.18  6.62 0.00 26.18 58.79 0.05 8.46 0.00 0.09  6.86 0.00 26.18 59.47 0.07 8.19 0.01 0.25  6.36 0.00 26.69 58.38 0.03 8.97 0.00 0.16  6.40 0.00 26.66 58.56 0.07 8.92 0.01 0.16  TOTAL  101.10  100.03  100.26  101.33  100.38  101.14  100.19  101.03  100.59  100.78  NA+ MG2+ AL3+ S14+ K+ CA2+ MN2+ FE2+  0.581 0.000 1.365 2.635 0.002 0.381 0.000 0.010  0.485 0.000 1.481 2.516 0.003 0.496 0.001 0.006  0.570 0.000 1.375 2.627 0.003 0.395 0.000 0.003  0.432 0.000 1.519 2.484 0.002 0.523 0.000 0.013  0.511 0.001 1.442 2.553 0.001 0.471 0.000 0.003  0.577 0.000 1.379 2.617 0.003 0.402 0.000 0.007  0.572 0.000 1.376 2.621 0.003 0.404 0.000 0.003  0.588 0.000 1.364 2.630 0.004 0.388 0.000 0.009  0.548 0.000 1.399 2.597 0.002 0.427 0.000 0.006  0.551 0.000 1.395 2.600 0.004 0.424 0.000 0.006  Cation Sum Anion Sum  4.974 8.000  4.988 8.000  4.972 8.000  4.973 8.000  4.982 8.000  4.984 8.000  4.979 8.000  4.984 8.000  4.979 8.000  4.980 8.000  Sample  _ c--4 3  FC16-2^FC16-3^FC16-4^FC16-5  4.971 8.000  NA2O MGO AL203 S102  F16-12 6.39 0.00 26.66 58.45  F16-13 6.20 0.00 27.32 57.93  F16-14 6.72 0.00 26.23 58.88  F16-15 6.40 0.00 26.93 58.31  F16-16 6.40 0.01 26.72 58.23  F16-17 6.37 0.00 26.49 58.23  F16-18 6.42 0.87 23.94 57.54  F16-19 7.05 0.00 25.66 59.89  PL28-1 6.87 0.01 26.55 58.62  PL28-2 7.10 0.00 25.83 59.70  Table II-D K2O CAO MNO FEO  0.06 8.89 0.01 0.27  0.07 8.68 0.01 0.14  0.11 8.43 0.01 2.69  0.08 7.54 0.00 0.14  0.08 8.39 0.00 0.04  0.06 7.45 0.03 0.02  TOTAL  100.61  101.27  100.58  100.79  100.59  99.99  100.01  100.36  100.56  100.19  NA+ MG2+ AL3+ S14+ K+ CA2+ MN2+ FE2+  0.551 0.000 1.397 2.599 0.002 0.424 0.000 0.006  0.533 0.000 1.427 2.567 0.003 0.443 0.000 0.016  0.579 0.000 1.374 2.618 0.003 0.406 0.000 0.006  0.551 0.000 1.409 2.589 0.003 0.424 0.000 0.007  0.552 0.001 1.402 2.592 0.003 0.424 0.000 0.010  0.552 0.000 1.396 2.603 0.004 0.416 0.000 0.005  0.565 0.059 1.280 2.611 0.006 0.410 0.000 0.102  0.607 0.000 1.342 2.658 0.005 0.359 0.000 0.005  0.592 0.001 1.391 2.606 0.005 0.400 0.000 0.001  0.612 0.000 1.353 2.653 0.003 0.355 0.001 0.001  Cation Sum Anion Sum  4.979 8.000  4.988 8.000  4.987 8.000  4.983 8.000  4.985 8.000  4.977 8.000  5.034 8.000  4.976 8.000  4.996 8.000  4.978 8.000  Sample  00  Amphibole/Plagioclase Microprobe Data 0.04 0.06 0.06 0.06 8.91 9.33 8.52 8.91 0.00 0.00 0.00 0.00 0.16 0.43 0.17 0.18  PL28-3  PL28-4  PL28-5  PL28-6  PL28-7  PL28-8  PL28-9  P28-10  P28-11  P28-12  NA2O MGO AL203 S102 K2O CAO MNO FEO  6.33 0.01 26.96 57.73 0.03 8.94 0.00 0.01  6.37 0.00 27.04 57.83 0.07 8.98 0.01 0.02  6.86 0.00 26.02 58.88 0.06 8.14 0.00 0.09  5.71 0.00 28.05 56.40 0.05 10.42 0.00 0.12  4.72 0.00 25.08 52.51 0.04 10.73 0.01 2.48  6.84 0.00 26.18 58.77 0.07 8.03 0.00 0.11  6.59 0.00 26.89 57.73 0.06 8.92 0.01 0.05  6.50 0.00 26.80 58.06 0.06 8.94 0.00 0.13  5.95 0.00 25.31 54.56 0.08 8.12 0.00 0.05  6.67 0.00 26.31 58.64 0.06 8.32 0.00 0.11  TOTAL  100.01  100.32  100.05  100.75  95.57  100.00  100.25  100.49  94.07  100.11  0.549  0.551  0.594  0.494  0.437  0.592  0.571  0.562  0.548  0.577  NA+  Table II-D  0.001 1.421 2.582 0.002 0.428 0.000 0.000  0.000 1.422 2.580 0.004 0.429 0.000 0.001  0.000 1.369 2.628 0.003 0.389 0.000 0.003  0.000 1.476 2.518 0.003 0.498 0.000 0.004  0.000 1.411 2.507 0.002 0.549 0.000 0.099  0.000 1.377 2.624 0.004 0.384 0.000 0.004  0.000 1.416 2.580 0.003 0.427 0.000 0.002  0.000 1.408 2.587 0.003 0.427 0.000 0.005  0.000 1.417 2.592 0.005 0.413 0.000 0.002  0.000 1.383 2.616 0.003 0.398 0.000 0.004  Cation Sum Anion Sum  4.983 8.000  4.987 8.000  4.986 8.000  4.993 8.000  5.007 8.000  4.986 8.000  4.999 8.000  4.991 8.000  4.976 8.000  4.982 8.000  Sample  a"c:)  Amphibole/Plagioclase Microprobe Data  MG2+ AL3+ SI4+ K+ CA2+ MN2+ FE2+  P28-13  P28-14  P28-15  P28-16  P28-17  P28-18  P28-19  P28-20  P28-21  P28-22  NA2O MGO AL203 S102 K2O CAO MNO FEO  6.38 0.01 26.61 57.24 0.08 9.48 0.00 0.07  6.32 0.00 26.97 57.59 0.05 9.00 0.00 0.12  6.28 0.00 26.97 57.47 0.06 9.10 0.00 0.10  7.16 0.11 24.95 58.66 0.26 7.03 0.02 1.61  0.06 8.15 17.42 40.45 10.26 0.13 0.21 18.62  2.58 1.42 10.75 75.03 1.14 4.17 0.08 5.58  6.76 0.00 26.29 58.16 0.05 8.37 0.00 0.13  7.02 0.00 25.76 59.14 0.10 7.90 0.01 0.12  6.48 2.14 18.29 53.30 0.31 5.88 0.14 12.54  6.69 0.00 25.12 57.01 0.06 7.61 0.00 0.01  TOTAL  99.87  100.05  99.98  99.80  95.30  100.75  99.76  100.05  99.08  96.50  NA+ MG2+ AL3+ S14+ K+ CA2+ MN2+ FE2+  0.556 0.001 1.410 2.573 0.005 0.457 0.000 0.003  0.548 0.000 1.422 2.577 0.003 0.432 0.000 0.004  0.545 0.000 1.424 2.575 0.003 0.437 0.000 0.004  0.625 0.007 1.325 2.642 0.015 0.339 0.001 0.061  0.006 0.664 1.122 2.211 0.716 0.008 0.010 0.851  0.218 0.092 0.552 3.269 0.063 0.195 0.003 0.203  0.588 0.000 1.389 2.607 0.003 0.402 0.000 0.005  0.607 0.000 1.355 2.639 0.006 0.378 0.000 0.004  0.607 0.154 1.042 2.576 0.019 0.305 0.006 0.507  0.599 0.000 1.368 2.635 0.004 0.377 0.000 0.000  Cation Sum  5.003  4.987  4.988  5.015  5.588  4.596  4.993  4.990  5.216  4.983  Table II-D Anion Sum  Amphibole/Plagioclase Microprobe Data 8.000^8.000^8.000^8.000  Sample  P28-23^P28-24^P28-25^P28-26  8.000 P28-27  8.000 P28-28  8.000 P28-29  8.000 P28-30  8.000 P28-31  8.000 P28-32  NA2O MGO AL203 S102 K2O CAO MNO FEO  6.60 0.00 26.65 58.36 0.07 8.88 0.01 0.13  5.43 0.87 20.87 49.48 1.25 4.96 0.06 9.66  7.55 0.00 24.29 59.94 0.43 6.19 0.00 1.56  6.67 0.00 26.61 58.64 0.07 8.37 0.01 0.19  6.09 0.00 27.29 57.07 0.03 9.62 0.01 0.16  5.79 0.02 27.92 56.73 0.05 10.06 0.00 0.10  6.06 0.00 27.30 57.32 0.08 9.36 0.00 0.03  6.09 0.01 27.62 57.03 0.05 9.44 0.02 0.04  6.01 0.00 27.38 56.87 0.06 9.56 0.00 0.11  6.88 0.01 26.27 59.13 0.06 7.84 0.00 0.08  TOTAL  100.70  92.58  99.96  100.56  100.27  100.67  100.15  100.30  99.99  100.27  NA+ MG2+ AL3+ S14+ K+ CA2+ MN2+ FE2+  0.569 0.000 1.397 2.595 0.004 0.423 0.000 0.005  0.538 0.066 1.256 2.527 0.081 0.271 0.003 0.413  0.657 0.000 1.284 2.689 0.025 0.297 0.000 0.059  0.575 0.000 1.394 2.607 0.004 0.399 0.000 0.007  0.528 0.000 1.439 2.554 0.002 0.461 0.000 0.006  0.501 0.001 1.468 2.530 0.003 0.481 0.000 0.004  0.525 0.000 1.439 2.563 0.005 0.449 0.000 0.001  0.528 0.001 1.455 2.549 0.003 0.452 0.001 0.001  0.523 0.000 1.447 2.551 0.003 0.459 0.000 0.004  0.593 0.001 1.377 2.630 0.003 0.374 0.000 0.003  Cation Sum Anion Sum  4.993 8.000  5.155 8.000  5.010 8.000  4.986 8.000  4.991 8.000  4.988 8.000  4.982 8.000  4.989 8.000  4.988 8.000  4.980 8.000  Sample NA2O MGO AL203 _^S102 c) K2O  PL9-1  PL9-2 7.42 1.26 23.35 59.76 0.53  6.54 0.00 26.98 58.27 0.09  PL9-3 4.09 7.63 22.34 45.58 0.27  PL9-4 6.75 0.00 26.40 58.56 0.06  PL9-5 6.21 0.79 24.63 56.35 0.14  PL9-6 6.38 0.01 27.15 57.83 0.08  PL9-7 6.19 0.00 27.15 57.35 0.06  PL9-8 6.67 0.00 26.33 58.72 0.07  PL9-9 6.38 0.00 27.08 57.66 0.06  PL9-10 6.50 0.00 26.75 57.95 0.08  Table II-D CAO MNO FEO  8.18 0.04 1.16  9.02 0.04 0.23  9.33 0.05 0.18  8.40 0.03 0.14  9.07 0.01 0.22  8.83 0.01 0.17  TOTAL  99.43  101.03  91.56  100.43  97.50  100.74  100.31  100.36  100.48  100.29  NA+ MG2+ AL3+ S14+ K+ CA2+ MN2+ FE2+  0.648 0.085 1.240 2.693 0.030 0.280 0.000 0.050  0.562 0.000 1.410 2.584 0.005 0.428 0.000 0.005  0.404 0.580 1.343 2.324 0.018 0.225 0.006 0.315  0.583 0.000 1.386 2.609 0.003 0.398 0.002 0.011  0.556 0.054 1.340 2.601 0.008 0.405 0.002 0.045  0.550 0.001 1.424 2.573 0.005 0.430 0.002 0.009  0.537 0.000 1.431 2.564 0.003 0.447 0.002 0.007  0.576 0.000 1.382 2.615 0.004 0.401 0.001 0.005  0.552 0.000 1.424 2.572 0.003 0.434 0.000 0.008  0.563 0.000 1.408 2.588 0.005 0.422 0.000 0.006  Cation Sum Anion Sum  5.026 8.000  4.995 8.000  5.215 8.000  4.991 8.000  5.011 8.000  4.992 8.000  4.990 8.000  4.984 8.000  4.993 8.000  4.992 8.000  Sample  _  Amphibole/Plagioclase Microprobe Data 4.12 8.33 9.00 5.79 0.01 0.14 0.04 0.00 7.39 0.14 0.29 1.32  PL9-11  PL91-2  PL9-13  PL9-14  PL9-15  PL9-16  PL9-17  PL9-18  PL9-19  PL9-20  NA2O MGO AL2O3 S102 K2O CAO MNO FEO  6.44 0.00 26.84 58.23 0.08 8.98 0.03 0.15  6.70 0.01 26.52 58.39 0.06 8.55 0.02 0.14  3.74 5.91 17.83 48.29 0.48 9.91 0.28 12.23  2.65 10.64 11.13 51.85 0.32 10.88 0.29 10.97  6.63 0.00 26.44 57.86 0.09 8.60 0.00 0.07  6.13 0.00 27.49 56.58 0.07 9.53 0.00 0.23  5.55 3.62 20.67 55.94 0.43 8.28 0.11 5.04  6.62 0.11 25.99 58.12 0.11 8.47 0.00 0.34  6.59 0.00 26.25 58.24 0.18 8.42 0.01 0.22  6.85 0.00 26.38 58.32 0.06 8.22 0.00 0.17  TOTAL  100.75  100.39  98.67  98.73  99.69  100.03  99.64  99.76  99.91  100.00  NA+ MG2+  0.555 0.000  0.579 0.001  0.358 0.435  0.252 0.778  0.577 0.000  0.534 0.000  0.499 0.250  0.576 0.007  0.572 0.000  0.594 0.000  Table II-D  1.406 2.588 0.005 0.428 0.001 0.006  1.393 2.602 0.003 0.408 0.001 0.005  1.038 2.386 0.030 0.525 0.012 0.505  0.643 2.543 0.020 0.572 0.012 0.450  1.399 2.597 0.005 0.414 0.000 0.003  1.455 2.541 0.004 0.459 0.000 0.009  1.129 2.592 0.025 0.411 0.004 0.195  1.375 2.609 0.006 0.407 0.000 0.013  1.386 2.609 0.010 0.404 0.000 0.008  1.390 2.608 0.003 0.394 0.000 0.006  Cation Sum Anion Sum  4.988 8.000  4.992 8.000  5.289 8.000  5.271 8.000  4.994 8.000  5.001 8.000  5.106 8.000  4.994 8.000  4.990 8.000  4.996 8.000  Sample  _ -N-1  Amphibole/Plagioclase Microprobe Data  AL3+ S14+ K+ CA2+ MN2+ FE2+  PL9-21  PL9-22  PL9-23  PL9-24  PL9-25  PL9-26  MC8-1  MC8-2  MC8-3  MC8-4  NA2O MGO AL203 S102 K2O CAO MNO FEO  6.78 0.00 26.33 58.02 0.06 8.44 0.01 0.26  4.46 4.95 18.96 53.60 0.76 9.19 0.15 6.12  3.09 9.31 13.17 53.81 0.17 10.70 0.26 8.62  6.28 0.31 25.68 57.40 0.39 7.82 0.01 0.57  6.40 0.00 27.08 57.89 0.07 9.04 0.00 0.20  6.33 0.00 25.78 58.15 0.73 7.58 0.03 0.21  10.28 0.08 21.19 65.80 0.64 1.04 0.04 0.22  10.53 0.00 20.70 64.95 0.07 0.90 0.00 0.03  11.17 0.00 20.19 67.14 0.06 0.65 0.02 0.20  10.25 0.09 20.92 66.21 0.49 1.01 0.00 0.11  TOTAL  99.90  98.19  99.13  98.46  100.68  98.81  99.29  97.18  99.43  99.08  NA+ MG2+ AL3+ S14+ K+ CA2+ MN2+ FE2+  0.589 0.000 1.391 2.601 0.003 0.405 0.000 0.010  0.412 0.351 1.064 2.552 0.046 0.469 0.006 0.244  0.287 0.666 0.745 2.581 0.010 0.550 0.011 0.346  0.554 0.021 1.377 2.611 0.023 0.381 0.000 0.022  0.552 0.000 1.420 2.576 0.004 0.431 0.000 0.007  0.555 0.000 1.375 2.631 0.042 0.367 0.001 0.008  0.881 0.005 1.104 2.910 0.036 0.049 0.001 0.008  0.919 0.000 1.098 2.923 0.004 0.043 0.000 0.001  0.953 0.000 1.048 2.956 0.003 0.031 0.001 0.007  0.879 0.006 1.090 2.927 0.028 0.048 0.000 0.004  Cation Sum Anion Sum  5.000 8.000  5.145 8.000  5.195 8.000  4.989 8.000  4.992 8.000  4.980 8.000  4.996 8.000  4.989 8.000  4.999 8.000  4.981 8.000  Table II-D  Amphibole/Plagioclase Microprobe Data  Sample  MC8-5^MC8-6^MC8-7^MC8-8  MC8-9  MC8-10  MC8-11  MC8-12  MC8-13  MC8-14  NA2O MGO AL203 S102 K2O CAO MNO FEO  11.03 0.01 19.96 67.41 0.09 0.57 0.01 0.09  10.52 0.00 20.66 67.17 0.11 1.23 0.00 0.10  10.89 0.01 20.20 66.76 0.14 0.77 0.03 0.17  10.91 0.00 20.45 66.51 0.08 0.89 0.00 0.15  10.43 0.06 20.34 65.85 0.35 0.76 0.00 0.28  9.63 0.14 20.71 62.27 0.96 1.56 0.02 0.72  11.22 0.00 20.01 67.52 0.11 0.72 0.02 0.10  10.99 0.00 20.22 67.08 0.04 0.67 0.02 0.01  11.03 0.00 20.41 67.68 0.08 0.78 0.01 0.10  10.37 0.08 21.21 66.71 0.88 0.60 0.01 0.15  TOTAL  99.17  99.79  98.97  98.99  98.07  96.01  99.70  99.03  100.09  100.01  NA+ MG2+ AL3+ S14+ K+ CA2+ MN2+ FE2+  0.942 0.001 1.036 2.970 0.005 0.027 0.000 0.003  0.894 0.000 1.067 2.944 0.006 0.058 0.000 0.004  0.934 0.001 1.053 2.953 0.008 0.036 0.001 0.006  0.936 0.000 1.066 2.942 0.005 0.042 0.000 0.006  0.903 0.004 1.071 2.941 0.020 0.036 0.000 0.010  0.860 0.010 1.125 2.870 0.056 0.077 0.001 0.028  0.955 0.000 1.035 2.964 0.006 0.034 0.001 0.004  0.940 0.000 1.051 2.959 0.002 0.032 0.001 0.000  0.934 0.000 1.051 2.957 0.004 0.037 0.000 0.004  0.882 0.005 1.096 2.925 0.049 0.028 0.000 0.006  Cation Sum Anion Sum  4.985 8.000  4.973 8.000  4.992 8.000  4.995 8.000  4.985 8.000  5.026 8.000  4.999 8.000  4.986 8.000  4.987 8.000  4.992 8.000  Sample NA2O MGO AL203 S102 K2O CAO  MC8-15 11.00 0.02 20.21 68.04 0.07 0.76  MC8-16 10.81 0.00 20.60 67.64 0.06 0.95  MC8-17 10.80 0.01 20.35 67.66 0.08 0.75  MC8-18 10.20 0.09 20.65 66.05 0.53 0.71  MC8-19 10.97 0.00 20.20 67.56 0.10 0.74  MC8-20 9.24 0.13 22.52 64.03 1.74 0.55  MC8-21 10.90 0.00 20.47 67.18 0.18 0.85  MC8-22 11.11 0.01 20.47 67.38 0.10 0.77  MC8-23 11.04 0.00 20.28 67.55 0.06 0.70  MC8-24 10.71 0.04 20.39 67.10 0.30 0.79  Table II-D  Amphibole/Plagioclase Microprobe Data 0.02 0.24  0.03 0.15  0.01 0.04  0.00 0.24  0.00 0.00  0.00 0.33  0.00 0.07  0.03 0.17  0.00 0.03  0.01 0.10  TOTAL  100.36  100.24  99.70  98.47  99.57  98.54  99.65  100.04  99.66  99.44  NA+ MG2+ AL3+ S14+ K+ CA2+ MN2+ FE2+  0.929 0.001 1.038 2.965 0.004 0.035 0.001 0.009  0.914 0.000 1.059 2.951 0.003 0.044 0.001 0.005  0.917 0.001 1.050 2.963 0.004 0.035 0.000 0.001  0.879 0.006 1.082 2.937 0.030 0.034 0.000 0.009  0.933 0.000 1.045 2.964 0.006 0.035 0.000 0.000  0.801 0.009 1.186 2.862 0.099 0.026 0.000 0.012  0.928 0.000 1.059 2.950 0.010 0.040 0.000 0.003  0.943 0.001 1.056 2.949 0.006 0.036 0.001 0.006  0.938 0.000 1.048 2.962 0.003 0.033 0.000 0.001  0.914 0.003 1.057 2.952 0.017 0.037 0.000 0.004  Cation Sum Anion Sum  4.983 8.000  4.979 8.000  4.973 8.000  4.977 8.000  4.983 8.000  4.995 8.000  4.990 8.000  4.997 8.000  4.985 8.000  4.984 8.000  MNO FEO  Sample  MC8-25  MC8-26  MC8-27  MC8-28  MC8-29  MC8-30  MC8-31  MC8-32  MC8-33  MC8-34  NA2O MGO AL203 S102 K2O CAO MNO FEO  11.13 0.00 19.75 68.05 0.03 0.37 0.00 0.02  10.95 0.02 20.29 67.20 0.21 0.48 0.01 0.17  8.28 0.22 21.73 60.29 0.94 4.49 0.00 1.98  10.55 0.00 20.67 66.77 0.09 1.32 0.01 0.03  10.97 0.02 20.41 67.16 0.28 0.78 0.04 0.28  10.29 0.25 20.80 65.77 0.85 0.78 0.02 0.57  10.16 0.08 21.15 65.67 0.76 0.97 0.01 0.26  10.88 0.03 20.31 67.50 0.13 0.72 0.00 0.08  10.57 0.33 20.53 65.91 0.22 0.81 0.04 0.50  10.93 0.00 20.66 67.07 0.10 0.84 0.00 0.08  TOTAL  99.35  99.33  97.93  99.44  99.94  99.33  99.06  99.65  98.91  99.68  NA+ MG2+  0.947 0.000  0.935 0.001  0.736 0.015  0.900 0.000  0.933 0.001  0.884 0.017  0.873 0.005  0.925 0.002  0.909 0.022  0.930 0.000  Table II-D  Amphibole/Plagioclase Microprobe Data  AL3+ S14+ K+ CA2+ MN2+ FE2+  1.022 2.987 0.002 0.017 0.000 0.001  1.053 2.959 0.012 0.023 0.000 0.006  1.175 2.765 0.055 0.221 0.000 0.076  1.072 2.938 0.005 0.062 0.000 0.001  1.055 2.946 0.016 0.037 0.001 0.010  1.086 2.915 0.048 0.037 0.001 0.021  1.105 2.911 0.043 0.046 0.000 0.010  1.050 2.960 0.007 0.034 0.000 0.003  1.073 2.924 0.012 0.039 0.002 0.019  1.069 2.943 0.006 0.039 0.000 0.003  Cation Sum Anion Sum  4.976 8.000  4.988 8.000  5.043 8.000  4.979 8.000  5.000 8.000  5.008 8.000  4.994 8.000  4.981 8.000  5.000 8.000  4.990 8.000  Sample  MC8-35  NA2O MGO AL203 S102 K2O CAO MNO FEO  9.49 2.06 19.19 61.83 0.10 1.09 0.01 2.76  TOTAL  96.53  NA+ MG2+ AL3+ S14+ K+ CA2+ MN2+ FE2+  0.849 0.142 1.043 2.853 0.006 0.054 0.000 0.106  Cation Sum Anion Sum  5.053 8.000  Amphibole/Plagioclase Calculations Table II-E Mineral ID cation ratios Fe (3+) Fe (2+) Al Cr (Hornblende) Ti Si 1.519 6.614 0.102 1.639 0.000 0.747 PL2-1 1.664 0.081 2.004 0.000 0.818 P12-2 6.345 0.868 1.528 PL2-3 6.316 0.058 2.126 0.001 1.475 0.034 1.889 0.002 0.875 6.501 PL2-4 1.602 6.507 0.059 1.930 0.003 0.684 PL2-5 0.835 1.525 PL2-6 6.438 0.100 1.858 0.001 1.520 PL2-10 6.327 0.042 2.092 0.000 0.912 1.578 6.360 0.099 1.921 0.000 0.851 PL2-11 1.525 PL2-12 6.338 0.048 2.046 0.000 0.899 1.572 PL2-14 6.407 0.115 1.874 0.000 0.830 1.460 PL2-16 6.490 0.054 1.945 0.000 0.764 PL2-17 6.411 0.112 1.918 0.000 0.747 1.575 1.611 PL2-18 6.418 0.097 1.890 0.000 0.760  111-12-1 HH2-4 HH2-7 HH2-8 HH2-9 1-11H2-11 H1-12-13 I-1112-15 HH2-16 HH2-17 HH2-19 HH2-20 HH2-22 HH2-23 1-11-12-26 1 1H2-27 -  6.433 6.389 6.168 6.658 6.564 6.367 6.391 6.238 6.496 6.416 6.559 6.336 6.346 6.809 6.342 6.329  0.050 0.052 0.046 0.086 0.088 0.060 0.055 0.051 0.089 0.075 0.064 0.054 0.054 0.092 0.053 0.006  2.059 2.128 2.431 1.695 1.759 2.114 2.091 2.364 1.925 2.005 1.844 2.152 2.162 1.518 2.177 2.235  0.002 0.000 0.000 0.007 0.000 0.000 0.000 0.008 0.001 0.000 0.000 0.001 0.005 0.000 0.000 0.000  0.781 0.798 0.882 0.658 0.756 0.791 0.825 0.831 0.684 0.876 0.775 0.862 0.830 0.567 0.829 0.724  1.414 1.451 1.413 1.372 1.413 1.433 1.431 1.431 1.353 1.184 1.279 1.440 1.390 1.305 1.323 1.597  Mn 0.069 0.086 0.080 0.085 0.088 0.093 0.086 0.078 0.089 0.080 0.085 0.082 0.092  Mg 2.321 1.993 2.040 2.149 2.131 2.150 2.020 2.105 2.050 2.131 2.219 2.155 2.134  Ca 1.862 1.906 1.850 1.869 1.882 1.889 1.889 1.902 1.897 1.867 1.851 1.887 1.880  0.085 0.094 0.081 0.085 0.090 0.085 0.093 0.081 0.081 0.077 0.090 0.092 0.084 0.080 0.075 0.083  2.190 2.109 1.984 2.467 2.344 2.153 2.120 2.022 2.378 2.391 2.416 2.079 2.151 2.652 2.213 1.974  1.859 1.844 1.875 1.851 1.853 1.879 1.870 1.849 1.872 1.836 1.830 1.855 1.848 1.858 1.860 1.869  Xab Holland and Blundy, 1994) T [C] P [kbar] Na^K^(Plag) 2.4 735 0.259^0.175^0.59 744 7.2 0.307^0.225^0.61 736 0.341^0.178^0.63 6.4 0.288^0.118^0.7 697 7.6 706 6.5 0.300^0.178^0.63 738 0.285^0.170^0.63 6.3 0.333^0.151^0.61 8.4 745 0.293^0.229^0.64 745 6.7 0.324^0.177^0.63 740 8.2 0.277^0.223^0.64 739 4.4 0.354^0.115^0.67 711 7.7 0.297^0.219^0.63 734 5.9 0.300^0.255^0.63 736 5.0 Mean 731.23 6.36 Standard Error 4.39 0.46 Standard Deviation 15.84 1.67 0.347^0.098^0.6 730 8.2 0.348^0.118^0.61 725 7.5 0.365^0.134^0.62 752 11.2 0.258^0.137^0.61 700 4.0 0.303^0.140^0.59 737 4.7 0.372^0.104^0.65 730 9.8 0.323^0.113^0.59 7.9 733 0.372^0.100^0.65 736 11.0 5.9 0.301^0.159^0.6 716 0.321^0.098^0.62 733 6.5 0.307^0.118^0.61 715 4.7 0.357^0.109^0.62 739 8.6 0.354^0.107^0.62 734 8.6 0.240^0.111^0.61 684 3.2 0.326^0.135^0.59 7.4 730 0.372^0.126^0.61 9.3 732 Mean 726.63 7.41 Standard Error 4.06 0.60 Standard Deviation 16.26 2.41  Table II-E Amphibole/Plagioclase Calculations Mineral ID cation ratios Si Ti Al Cr Fe (3+) Fe (2+) (Hornblende) FC16-1 FC16-2 FC16-3 FC16-5 FC16-8 FC16-9 FC16-19 FC16-20 FC16-21 FC16-22 FC16-23 FC16-25 FC16-26 FC16-27  6.385 6.471 6.433 6.443 6.343 6.482 6.691 6.508 6.522 6.550 6.390 6.392 6.516 6.356  0.072 0.101 0.080 0.097 0.093 0.099 0.063 0.103 0.089 0.081 0.093 0.090 0.089 0.099  2.367 1.986 2.111 2.107 2.280 2.079 1.779 2.079 2.076 2.084 2.207 2.117 1.982 2.132  0.000 0.009 0.002 0.000 0.000 0.000 0.001 0.017 0.000 0.004 0.019 0.003 0.002 0.000  0.502 0.751 0.707 0.667 0.614 0.614 0.630 0.505 0.575 0.539 0.634 0.726 0.647 0.862  2.262 2.012 2.059 2.075 2.101 1.954 1.912 2.038 1.976 1.970 1.967 1.916 1.931 2.042  Mn  Mg  Ca  0.042 0.066 0.066 0.064 0.086 0.081 0.065 0.092 0.084 0.074 0.084 0.085 0.071 0.061  1.394 1.711 1.583 1.584 1.510 1.730 1.969 1.721 1.723 1.748 1.683 1.706 1.797 1.563  1.833 1.715 1.803 1.805 1.830 1.802 1.734 1.785 1.790 1.788 1.765 1.817 1.817 1.702  Xab Holland and Blundy, 1994) T [C] P [kbar] Na^K^(Plag) 0.401^0.099^0.61 0.378^0.088^0.6 0.359^0.109^0.49 0.358^0.102^0.45 0.383^0.140^0.52 0.373^0.088^0.59 0.318^0.076^0.6 0.372^0.109^0.56 0.360^0.097^0.56 0.350^0.085^0.54 0.379^0.115^0.59 0.366^0.121^0.56 0.345^0.111^0.58 0.373^0.092^0.63  Mean Standard Error Standard Deviation MC8-10 MC8-19  6.782 6.780  0.081 0.082  1.396 1.359  0.001 0.001  0.739 0.761  1.305 1.309  0.055 0.048  2.638 2.647  1.895 1.916  0.235^0.119^0.87 0.224^0.127^0.73  Mean Standard Error Standard Deviation PL28-1 PL28-5 PL28-7 PL28-10 PL28-11 PL28-13 PL28-14 PL28-15 PL28-18 PL28-19  --A  7.033 6.720 6.708 6.807 6.835 7.012 6.593 6.959 6.552 6.890  0.059 0.067 0.036 0.098 0.084 0.076 0.035 0.032 0.039 0.036  1.299 1.825 1.872 1.639 1.648 1.371 2.102 1.508 2.140 1.658  0.000 0.002 0.001 0.000 0.000 0.000 0.002 0.003 0.001 0.000  0.435 0.469 0.482 0.400 0.373 0.346 0.444 0.398 0.475 0.360  1.738 1.789 1.887 1.890 1.852 1.767 2.070 1.923 2.068 2.040  0.067 0.070 0.075 0.059 0.072 0.069 0.061 0.074 0.067 0.071  2.364 2.051 1.933 2.087 2.124 2.356 1.687 2.095 1.653 1.928  1.917 1.902 1.900 1.929 1.911 1.915 1.901 1.912 1.898 1.921  0.177^0.082^0.59 0.223^0.114^0.56 0.239^0.130^0.64 0.199^0.136^0.46 0.205^0.138^0.59 0.177^0.105^0.65 0.249^0.153^0.57 0.199^0.103^0.6 0.268^0.148^0.53 0.209^0.113^0.51  Mean Standard Error Standard Deviation  705 734 744 745 738 713 690 707 699 692 715 741 716 733  10.0 4.8 5.2 5.2 6.9 6.3 4.0 5.7 5.0 5.0 6.2 6.2 5.6 5.0  719.43 5.21 19.48  5.79 038 1.42  631 689  9.7 5.7  660.00 29.00 41.01  7.70 2.00 2.83  641 650 633 668 630 614 643 620 667 634  2.5 4.8 6.4 3.1 3.2 3.6 6.7 3.8 6.9 4  640.00 5.66 17.90  4.50 0.51 1.62  ^  Table II-E^Amphibole/Plagioclase Calculations Xab Holland and Blundy, 1994) Mineral ID cation ratios [C]^P [kbar] ^Fe Cr FeMn^Mg^Ca^Na^K^(flag)^T (3+) Si Ti^Al (Hornblende) (2+) ^1.035^0.057^2.918^1.887^0.249^0.054^0.68^657^6.1 0.000 0.595 ^0.031^1.459 6.904 PL9-1 1.063^0.062^2.922^1.880^0.270^0.055^0.57^688^4.7 0.031^1.438 0.003 0.571 6.916 PL9-2 1.166^0.065^2.679^1.897^0.299^0.093^0.63^686^7.8 6.690 PL9-3 0.049^1.753 0.000 0.593 0.044^1.552 0.000 0.642 1.020^0.064^2.875^1.920^0.250^0.085^0.59^693^6.4 6.787 PL9-4 ^ 0.016 0.563 1.214^0.057^2.709^1.902^0.274^0.089^0.57^696^7.7 6.744 0.044^1.661 PL9-5 ^ 0.008 0.751 1.088^0.068^2.640^1.892^0.264^0.094^0.56^717^6.8 6.593 0.046^1.811 PL9-6 ^ 1.342^0.064^2.316^1.858^0.386^0.095^0.54^732^8.8 6.438 PL9-7 0.037 2.176 0.004 0.641 1.133^0.076^2.595^1.876^0.291^0.111^0.56^725^5.9 0.759 0.049^1.812 0.002 6.581 PL9-9 ^ 1.053^0.060^2.820^1.853^0.273^0.076^0.57^701^3.7 0.036^1.565 0.000 0.685 6.796 PL9-10 ^ 0.032^1.402 0.003 0.674 0.889^0.059^3.055^1.886^0.222^0.062^0.56^694^3.3 6.893 PL9-11 1.241^0.056^2.501^1.903^0.327^0.089^0.58^703^9.5 0.000 0.583 6.563 0.037^2.011 PL9-12 1.062^0.060^2.725^1.902^0.281^0.096^0.39^747^6.2 0.041^1.733 0.000 0.722 6.650 PL9-13 1.047^0.067^2.910^1.911^0.235^0.081^0.3^722^4.6 6.872 0.034^1.486 0.005 0.571 PL9-14 1.097^0.068^2.690^1.906^0.307^0.081^0.54^723^8.2 6.634 0.039^1.795 0.004 0.668 PL9-16 ^ 0.003 1.133^0.059^2.670^1.891^0.281^0.102^0.53^709^6.4 6.649 0.045^1.811 0.630 PL9-17 ^ 6.762 0.037^1.591 0.007 0.638 1.064^0.048^2.845^1.919^0.262^0.084^0.58^699^7.4 PL9-18 ^ 6.528 0.035^1.908 0.000 0.808 1.041^0.064^2.619^1.878^0.306^0.087^0.58^725^7.3 PL9-19 6.816 0.039^1.509 0.004 0.665 1.014^0.058^2.890^1.904^0.237^0.076^0.6^688^5.6 PL9-20 1.068^0.049^2.862^1.871^0.286^0.073^0.59^692^5.2 6.812 0.035^1.567 0.004 0.613 PL9-21 1.075^0.059^2.784^1.881^0.275^0.088^0.44^746^6.9 6.675 0.040^1.666 0.024 0.704 PL9-22 1.046^0.058^2.880^1.913^0.275^0.057^0.34^739^6.8 6.812 0.034^1.539 0.006 0.617 PL9-23 0.993^0.062^2.824^1.902^0.237^0.077^0.58^698^5.1 0.033^1.592 0.000 0.737 6.751 PL9-24 1.041^0.055^2.755^1.877^0.278^0.076^0.56^711^5.8 6.690 0.034^1.704 0.002 0.725 PL9-25 1.139^0.057^2.929^1.866^0.259^0.105^0.58^672^4.0 6.921 0.035^1.454 0.015 0.474 PL9-26  ^Mean  706.79^6.26 Standard Error^4.63^0.32 Standard Deviation^22.66^1.58  APPENDIX III U/Pb and Ar/Ar Geochronology; Methodology and Data  U/Pb LA-ICPMS Methodology  Laser ablation ICP-MS dating has recently been established as a routine procedure at the PCIGR. Zircons are separated from their host rocks using conventional mineral separation methods. Approximately 25 of the coarsest, clearest, most inclusion free grains are selected from each sample, mounted in an epoxy puck along with several grains of internationally accepted the —1100 Ma FC-1 standard zircon, and brought to a very high polish. The grains are examined using a stage-mounted cathodoluminescence unit, which makes it possible to detect the presence of altered zones or older inherited cores within the zircon. High-quality portions of each grain, free of alteration, inclusion, or cores, are selected for analysis. The surface of the mount is then washed for —10 minutes with dilute nitric acid and rinsed in high purity water. Analyses are carried out using a New Wave 213 nm Nd-YAG laser coupled to a Thermo Finnigan Element2 highresolution ICP-MS. Ablation takes place within a New Wave "Supercell" ablation chamber which is designed to achieve very high efficiency entrainment of aerosols into the carrier gas. Helium is used as the carrier gas for all experiments and gas flow rates, together with other parameters such as torch position, are optimized prior to beginning a series of analyses. A 25 micron spot with 40% laser power is used, making line scans rather than spot analyses in order to avoid within-run elemental fractions. Each analysis consists of a 7-second background measurement (laser off) followed by a —28-second data acquisition period with the laser firing. A typical analytical session consists of four analyses of the standard zircon, followed by four analyses of unknown zircons, two standard analyses, four unknown analyses, etc., and finally four standard analyses. Data are reduced using the GLITTER software marketed by the GEMOC group at Macquarrie  179  University in Sydney, Australia, which automatically subtracts background measurements, propagates all analytical errors, and calculates isotopic ratios and ages. The time resolved signal from each analysis is carefully examined, and portions of the signal that are interpreted to reflect the effects of post-crystallization Pb-loss and/or the presence of older inherited zircon cores are excluded from calculation of the final isotopic ratios. Interpreted crystallization ages are based on a weighted average of the calculated 206v0/238U ages for 8-20 individual analyses from each sample. Errors for the final interpreted age for each sample are given at the 2-sigma level using the method of Ludwig (2003). U/Pb sample descriptions are presented in Table III-A, and data are presented in Table III-B.  Ar/Ar Methodology  Each sample was crushed to fragments ranging in size from approximately 0.5 to 3 mm. 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), 28.02 Ma (Renne et al., 1998). The samples were irradiated on November 8 through November 10, 2007 at the McMaster Nuclear Reactor in Hamilton, Ontario, for 72 MWH, with a neutron flux of approximately 6x10' 3 neutrons/cm 2/s. Analyses (n=42) of 14 neutron flux monitor positions produced errors of <0.5% in the J value. The samples were analyzed on December 3 through December 7, 2007, at the Noble Gas Laboratory, Pacific Centre for Isotopic 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 lOW CO 2 laser (New Wave 180  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 sensitivity, mass discrimination, radioactive decay during and subsequent to irradiation, as well as interfering Ar from atmospheric contamination and the irradiation of Ca, Cl and K (Isotope production ratios: ( 40Ar/ 39Ar) K =0.0302±0.00006, ( 37Ar/ 39Ar) ca =1416.4±0.5, ( 36 Ar/ 39Ar)ca =0.3952±0.0004, Ca/K= 1 . 83 ±0 . 01 ( 37  Arcl 39 ArK).).  Ar/Ar sample descriptions are presented in Table III-A, and data are presented in Table III-C.  181  REFERENCES  Ludwig, K.R 2003. Isoplot 3.09 A Geochronological Toolkit for Microsoft Excel. Berkeley Geochronology Center, Special Publication No. 4 Renne, P.R., C.Swisher, C.C., III, Deino, A.L., Karner, D.B., Owens, T. and DePaolo, D.J., 1998. Intercalibration of standards, absolute ages and uncertainties in 40Ar/39Ar dating. Chemical Geolology, 145(1-2): 117-152.  182  Table III-A Sample  Geochronology Sample Locations and Descriptions UTM East UTM North  Sample Description  Minerals  Method  HH 1  643188  5833888  Mafic dyke. Cross-cuts foliated diorite with elongated mafic enclaves.  b  Ar/Ar  MC10  643070  5840461  Clay quartz schist from high strain zone on Mount Cloud.  b  Ar/Ar  5793279  Hornblende schist. Folded metasedimentary rock from Snootli Peak  b  Ar/Ar  5812727  Medium-grained, undeformed gabbro from within high strain zone on Mount Pootlass  b, h  Ar/Ar  5812593  Muscovite-chlorite-quartz mylonite from high strain zone on Mount Pootlass  z  U/Pb  5812471  Foliated chlorite cataclasite from brittle dextral fault within high strain zone on Mount Pootlass  m  Ar/Ar  5813152  Folded and sinistrally sheared mafic dyke within foliated granite within high strain zone on Mount Pootlass. Sample collected in proximity to 1-tectonite.  h  Ar/Ar  5812779  Chlorite-biotite schist, metasedimentary rock from within high strain zone on Mount Pootlass  b  Ar/Ar  5812136  Foliated granite sill within metasedimentary package in high strain zone on Mount Pootlass.  z  U/Pb  SS3  PL3  PL7  PL20  PL30  PL31  PL40  665501  650181  652079  649971  649785  649848  650037  All coordinates NAD 27 for Canada, UTM Zone 9 Abbreviations: z-zircon, h-hornblende, b-biotite, m-muscovite  183  Table III-B^U/Pb LA-ICPMS Data Isotopic Compositions (1 sigma errors) Pb207/Pb206 Pb207/U235 error 0.0234 0.10268 PL-40 1 0.04337 PL-40 2 0.04763 0.01174 0.11423 0.00999 PL-40 3 0.04564 0.11558 0.01084 0.1688 PL-40 4 0.07061 PL-40 5 0.02257 0.00852 0.05963 0.01187 PL-40 6 0.08361 0.20868 PL-40 7 0.0522 0.00361 0.12827 PL-40 8 0.05569 0.02623 0.13893 PL-40 9 0.03987 0.00617 0.09913 0.01504 PL-40 10 0.03305 0.08637 0.01998 0.10712 PL-40 11 0.04567 PL-40 12 0.01864 0.13527 0.05617 0.01356 PL-40 13 0.03451 0.08471 PL-40 14 0.04202 0.00871 0.09826 0.01506 0.12412 PL-40 15 0.05314 Isotopic Ages (1 sigma errors) Pb207/Pb206 error 830.33 PL-40 1 0.1 80 500.74 PL-40 2 437.31 PL-40 3 0.1 286.16 PL-40 4 946.2 PL-40 5 0 0.1 1283.4 254.24 PL-40 6 PL-40 7 294.3 150.49 439.7 803.93 PL-40 8 PL-40 9 0.1 0 103.39 PL-40 10 0.1 PL-40 11 795.33 0.1 458.5 604.63 PL-40 12 102.88 PL-40 13 0.1 228.37 PL-40 14 0.1 PL-40 15 334.6 539.81  Pb207/U235 99.3 109.8 111.1 158.4 58.8 192.4 122.5 132.1 96 84.1 103.3 128.8 82.6 95.2 118.8  error Pb206/U238 error 0.05522 0.017 0.00104 0.02804 0.01788 0.00068 0.02523 0.01916 0.00066 0.02561 0.01766 0.00069 0.02249 0.01814 0.00057 0.02919 0.01699 0.00066 0.00885 0.018 0.00031 0.06515 0.00119 0.01804 0.0153 0.01784 0.00049 0.0392 0.01751 0.00089 0.04669 0.01794 0.00097 0.01784 0.00104 0.0446 0.03323 0.01796 0.00076 0.02031 0.01749 0.0006 0.0349 0.01763 0.00103  error 50.85 25.55 22.96 22.25 21.55 24.52 7.97 58.08 14.14 36.64 42.82 39.89 31.1 18.77 31.53  Pb206/U238 108.6 114.2 122.3 112.8 115.9 108.6 115 115.2 114 111.9 114.6 114 114.8 111.8 112.7  error 6.6 4.32 4.17 4.39 3.59 4.2 1.96 7.56 3.12 5.65 6.15 6.59 4.84 3.81 6.5  Th232 3045 7391 7318 4401 6308 7755 20546 2243 12798 6527  U235 116 213 254 222 302 221 868 93 496 179  U238 15948 28050 32927 29444 43187 31826 116122 12646 67782 26256  Hg202 Hg204 0 0 0 0 0 0 0 54 0 0 0 33 39 0 11 1 0 0 0 0 40 20 0 8 4 0 0 0 27 8  Background Corrected Counts per Second PL-40 1 PL-40 2 PL-40 3 PL-40 4 PL-40 5 PL-40 6 PL-40 7 PL-40 8 PL-40 9 PL-40 10  Pb206 268 497 625 514 775 535 2067 225 1194 454  Pb207 11 23 28 36 17 44 107 12 47 14  Pb208 62 115 63 32 56 65 230 36 154 53  184  Background Corrected Counts per Second  PL-40 11 PL-40 12 PL-40 13 PL-40 14 PL-40 15  Pb206 322 334 444 768 436  Pb207 14 18 15 32 23  Pb208 53 70 69 115 47  Th232 3369 3848 5577 12278 6022  U235 142 143 187 340 193  U238 18232 19005 25092 44577 25109  185  Table III-C^A r/Ar Data Laser Power  Isotope Ratios 40Ar/39Ar^38Ar/39Ar^37Ar/39Ar^36Ar/39Ar^Ca/K^Cl/K %40Ar atm f 39Ar 40Ar*/39ArK ^Age  HH1, biotite, J = 0.00905010.000012, volume 39ArK = 488.52 x 10^-10 cm3, integrated age 110.91±0.46 Ma (2-s) 2  111.4025±0.0634  0.1051±0.4900  0.3363±0.2344  0.4042±0.1338  0.638  0.006  95.24  0.02  2.305±14.480  37.25+231.59  2.2  61.9112 0.0130  0.1042 0.0642  0.9811 0.0274  0.1657 0.0443  2.896  0.014  76.88  0.39  13.494 2.155  207.86 31.35  2.4  20.7214 0.0248  0.0669 0.0778  0.8971 0.0288  0.0479 0.0306  2.658  0.01  63.89  0.86  6.893 0.514  109.18 7.90  2.6  12.5450 0.0303  0.0541 0.0913  1.0403 0.0365  0.0266 0.0598  3.087  0.008  55.59  1.05  4.983 0.513  79.58 8.02  2.8  10.8146 0.0066  0.0505 0.0744  1.8287 0.0170  0.0171 0.0329  5.443  0.008  38.58  1.59  6.106 0.174  97.04 2.69  3  9.2116 0.0060  0.0616 0.0490  2.1578 0.0143  0.0120 0.0433  6.362  0.01  31.4  3.01  5.997 0.158  95.34 2.45  3.2  8.2053 0.0051  0.0789 0.0149  2.2522 0.0141  0.0087 0.0459  6.642  0.015  24.02  4.17  5.973 0.122  94.98  1.89  3.4  7.5467 0.0058  0.1340 0.0213  3.0998 0.0131  0.0051 0.0518  9.152  0.027  11.91  7.13  6.472 0.088  102.68  1.35  3.6  7.4984 0.0069  0.1762 0.0172  3.5886 0.0139  0.0037 0.0390  10.601  0.037  6.61  11.59  6.888 0.065  109.10  1.00  3.8  7.6093 0.0073  0.2245 0.0121  3.0355 0.0143  0.0026 0.0353  8.962  0.049  3.91  18.47  7.231 0.061  114.36 0.94  4.1  7.5972 0.0064  0.2177 0.0129  3.1168 0.0130  0.0027 0.0413  9.203  0.047  3.68  15.35  7.224 0.058  114.25 0.89  4.3  7.6046 0.0104  0.2298 0.0166  3.1119 0.0171  0.0027 0.0411  9.188  0.05  3.48  14.34  7.240 0.084  114.49  4.6  7.6419 0.0087  0.1990 0.0279  2.7954 0.0155  0.0029 0.0563  8.251  0.043  4.29  10.07  7.175 0.081  113.49  1.24  4.8  7.5902 0.0052  0.1888 0.0102  2.7748 0.0130  0.0029 0.0632  8.189  0.04  3.84  8.2  7.129 0.066  112.80  1.02  5  7.856! 0.0063  0.1621 0.0179  2.8412 0.0142  0.0041 0.0655  8.385  0.034  5.65  3.76  7.066 0.093  111.83  1.43  1.29  MCIO, biotite, J = 0.009053±0.000012, volume 39ArK = 743.54 x 10^-10 cm3, integrated age 76.3610.44 Ma (2-s)  2  108.5664±0.0177  0.1519±0.0822  0.6492±0.0476  0.3619±0.0259  1.899  0.016  98.32  0.4  1.759±2.142  2.2  20.8508 0.0074  0.0737 0.0344  0.5150 0.0168  0.0601 0.0266  1.511  0.011  83.68  1.02  3.233 0.464  52.05 7.37  2.4  19.8231 0.0075  0.0437 0.0668  0.4211 0.0211  0.0573 0.0212  1.236  0.004  84.2  1.3  2.995 0.364  48.26 5.79  28.50±34.44  2.6  12.8744 0.0186  0.0345 0.0531  0.3270 0.0246  0.0300 0.0261  0.961  0.003  67.79  3.29  4.029 0.253  64.63 3.99  2.8  8.2636 0.0215  0.0209 0.0380  0.1306 0.0279  0.0123 0.0384  0.383  0.001  42.12  4.86  4.646 0.185  74.33 2.90  3  6.8510 0.0177  0.0184 0.0560  0.1062 0.0376  0.0060 0.0387  0.311  0.001  23.48  4.81  5,070 0.126  80.96 1.97  3.2  6.7029 0.0080  0.0243 0.0393  0.2498 0.0193  0.0061 0.0267  0.734  0.002  24.39  6.47  4.933 0.063  78.82 0.99  3.4  5.6063 0.0065  0.0369 0.0218  0.1452 0.0178  0.0027 0.0430  0.427  0.005  12.45  9.6  4.795 0.048  76.67 0.76  3.6  5.1275 0.0066  0.0460 0.0286  0.1447 0.0175  0.0012 0.0507  0.429  0.007  5.22  15  4.772 0.038  76.29 0.59  3.8  4.9593 0.0095  0.1789 0.0139  0.6724 0.0151  0.0009 0.0436  1.997  0.038  3.15  31.67  4.746 0.048  75.90 0.75  4  5.2413 0.0087  0.0419 0.0325  0.7265 0.0171  0.0014 0.0550  2.158  0.006  4.75  12.35  4.895 0.050  78.22 0.78  4.2  5.9749 0.0075  0.0593 0.0292  0.6513 0.0165  0.0027 0.0492  1.934  0.01  8.98  5.17  5.254 0.057  83.84 0.89  4.5  6.3106 0.0054  0.0517 0.0486  0.7789 0.0164  0.0034 0.0476  2.314  0.009  10.73  4.07  5.413 0.058  86.30 0.90  MCIO, hornblende, J = 0.00905510. 000012, volume 39ArK = 608.12 x 10" - 10 cm3, integrated age 76.6810.37 Ma (2 - s)  2  46.4667±0.0126  0.0910±0.1748  0.9862±0.6605  0.1425±0.0506  2.966  0.012  89.07  0.29  4.902±2.224  78.35±34.78  2.3  35.1337 0.0087  0.0665 0.0658  1.0135 0.1520  0.1056 0.0255  3.138  0.007  88.07  1.06  4.093 0.772  65.66 12.16  2.6  11.9353 0.0075  0.0368 0.0707  0.5366 0.1602  0.0277 0.0217  1.647  0.004  66.06  2.12  3.843 0.175  61.71^2.76  2.9  7.4744 0.0055  0.0209 0.0757  0.6652 0.0413  0.0118 0.0330  2.067  0.001  43.27  4.99  4.073 0.118  65.34^1.87  3.2  4.9830 0.0056  0.0142 0.0351  0.4389 0.0316  0.0017 0.0446  1.367  0  7.59  18.86  4.512 0.035  72.24 0.55  3.5  4.8039 0.0053  0.0133 0.0295  0.6588 0.0164  0.0010 0.0522  2.056  0  3.33  24.34  4.563 0.030  73.05 0.47  3.8  5.6675 0.0088  0.0277 0.0220  3.8277 0.0151  0.0057 0.0226  12.033  0.003  16.47  5.55  4.535 0.058  72.60 0.90  4.1  7.0679 0.0060  0.1149 0.0294  12.1383 0.0158  0.0143 0.0343  38.707  0.023  30.94  2.85  4.623 0.152  73.98 2.38  4.4  8.1236 0.0088  0.1004 0.0286  21.5156 0.0172  0.0218 0.0418  70.819  0.019  30.92  1.1  4.964 0.288  79.33 4.50  5  5.9873 0.0043  0.0519 0.0139  1.8737 0.0126  0.0032 0.0237  5.863  0.009  10.87  38.85  5.286 0.033  84.34 0.51  PL3, biotite, J = 0.01013510.000012 , volume 39ArK = 615.16 x 10A - 10 cm3 , integrated age 77.1510.56 Ma (2 - s)  2  133.464±0.024  0.810±0.044  0.798±0.033  0.313±0.073  3.541  0.172  66.01  0.26  42.487±6.856  646.04±87.63  2.2  82.231 0.009  0.509 0.030  0.812 0.024  0.209 0.021  3.624  0.106  73.36  0.64  20.959 1.262  347.50 19.03  2.4  35.844 0.008  0.188 0.029  0.688 0.021  0.099 0.028  3.099  0.036  79.51  1.26  6.937 0.793  122.58 13.54  2.6  12.928 0.007  0.078 0.035  0.551 0.020  0.029 0.029  2.484  0.014  63.18  2.74  4.415 0.252  78.96 4.41  2.8  7.621 0.006  0.061 0.048  0.457 0.018  0.012 0.033  2.061  0.01  42.11  5.06  4.111 0.123  73.65 2.16  3  4.946 0.007  0.034 0.036  0.352 0.014  0.004 0.042  1.588  0.004  16.58  10.57  3.908 0.057  70.07 1.00  3.2  4.538 0.004  0.046 0.016  0.494 0.013  0.002 0.044  2.232  0.007  11.11  32.31  3.938 0.035  70.61^0.62  186  Table III-C  ^  Laser Power  Ar/Ar Data Isotope Ratios  40Ar/39Ar  38Ar/39Ar  37Ar/39Ar  36Ar/39Ar  Ca/K  Cl/K  %40Ar atm  f 39Ar  40Ar*/39ArK  Age  3.4  4.459 0.004  0.082 0.013  0.826 0.013  0.002 0.043  3.733  0.016  8.21  20  3.956 0.034  70.92 0.59  3.6  4.696 0.009  0.047 0.021  0.838 0.014  0.003 0.036  3.79  0.008  9.86  9.94  3.990 0.052  71.52 0.92  3.8  5.300 0.005  0.161 0.012  1.339 0.013  0.004 0.066  6.062  0.034  11.2  9.77  4.468 0.078  79.90 1.36  4  5.652 0.005  0.093 0.016  1.306 0.015  0.005 0.071  5.916  0.018  16.32  5.45  4.343 0.118  77.71 2.06  4.3  7.584 0.005  0.183 0.023  2.822 0.014  0.010 0.050  12.681  0.039  18.18  2  5.229 0.160  93.17 2.78  PL3, hornblende, J = 0.010132+0.000012, volume 39ArK = 242.26 x 10^ - 10 cm3, integrated age 80.91+1.13 Ma (2 - s)  2  111.607±0.032  0.586±0.073  1.574±0.044  0.308±0.078  4.859  0.138  72.21  0.15  28.599±8.123  459.07±115.13  2.2  138.581 0.021  0.766 0.054  1.187 0.037  0.360 0.041  4.387  0.168  73.64  0.38  36.206 4.267  563.79 57.06  2.4  84.676 0.012  0.477 0.041  1.042 0.021  0.224 0.029  4.334  0.099  76.06  0.98  19.747 1.877  329.03 28.59  2.6  51.351 0.012  0.246 0.030  0.894 0.024  0.140 0.048  3.765  0.048  78.28  1.37  10.642 2.003  184.73 33.04  2.8  33.882 0.017  0.127 0.077  0.978 0.027  0.093 0.069  3.679  0.022  71.14  0.54  7.824 1.957  137.63^33.14  3  46.703 0.009  0.173 0.053  0.997 0.018  0.133 0.023  4.333  0.031  82.6  1.92  7.812 0.881  137.43^14.92  3.2  18.484 0.012  0.119 0.029  0.876 0.021  0.045 0.039  3.89  0.022  68.44  3.97  5.484 0.526  97.55^9.11  3.4  7.513 0.009  0.052 0.039  0.728 0.017  0.012 0.046  3.252  0.008  40.24  6.29  4.044 0.176  72.45^3.08  3.6  6.245 0.009  0.054 0.026  0.792 0.015  0.008 0.032  3.589  0.009  34.2  17.1  3.911 0.092  70.10^1.62  3.9  7.078 0.008  0.139 0.013  1.547 0.014  0.011 0.039  7.044  0.028  39.24  12.35  4.061 0.137  72.74^2.41  4.2  6.379 0.006  0.206 0.015  1.800 0.014  0.010 0.033  8.22  0.044  36.01  19.09  3.912 0.100  70.13^1.75  5  5.491 0.004  0.044 0.018  0.753 0.013  0.006 0.034  3.425  0.007  25.38  35.86  3.976 0.060  71.26^1.05 64.31±48.43  PL20, muscovite, J = 0.009047+0.000012, volume 39ArK = 548.64 x 10A - 10 cm3, integrated age 62.42+0.71 Ma (2 - s)  2  61.7557±0.0094  0.0973±0.1480  1.7999±0.0224  0.1989±0.0529  3.758  0.011  93.08  0.36  4.011±3.075  2.2  11.0231 0.0077  0.0411 0.1111  2.2280 0.0208  0.0268 0.0415  6.173  0.005  62.64  1.12  3.674 0.328  58.99 5.18  2.4  6.3387 0.0670  0.0242 0.2194  16.6152 0.0707  0.0192 0.0552  50.717  0.001  51.1  4.71  2.994 0.372  48.22 5.91  2.6  5.4550 0.0058  0.0212 0.0623  30.3365 0.0130  0.0207 0.0256  94.251  0  33.06  5.53  3.593 0.161  57.71^2.55  2.8  4.9045 0.0116  0.0178 0.0225  20.0587 0.0168  0.0130 0.0247  61.588  0  21.06  14.21  3.859 0.105  61.90^1.66  3  4.8228 0.0169  0.0164 0.0359  14.0424 0.0204  0.0096 0.0238  42.81  0  18.21  20.38  3.925 0.097  62.95^1.53  3.2  4.2056 0.0257  0.0144 0.0456  3.0635 0.0269  0.0020 0.0336  9.277  0  2.57  22.58  4.024 0.109  64.51^1.71  3.4  4.3137 0.0163  0.0151 0.0512  2.1466 0.0240  0.0022 0.0497  6.454  0  4.56  10.1  3.974 0.076  63.73^1.19  3.7  4.1782 0.0159  0.0150 0.0465  0.1204 0.1711  0.0008 0.0990  0.33  0  2.99  17.39  3.950 0.069  63.34^1.09  4  4.7467 0.0071  0.0192 0.0740  0.3356 0.2287  0.0024 0.0988  0.851  0.001  5.17  3.61  4.138 0.078  66.31^1.23 62.17±28.43  PL30, hornblende, J = 0.010122+0.000012, volume 39ArK = 1173.5 x 10A - 10 cm3, integrated age 61.19+0.26 Ma (2 - s)  2  34.126±0.015  0.085±0.120  0.386±0.043  0.105±0.053  1.733  0.012  88.36  0.19  3.464±1.611  2.2  17.991 0.012  0.058 0.072  0.303 0.028  0.052 0.034  1.381  0.008  82.14  0.41  2.842 0.486  51.17 8.62  2.4  9.196 0.009  0.033 0.081  0.314 0.021  0.020 0.074  1.446  0.004  57.61  0.73  3.410 0.434  61.21^7.66  2.6  5.586 0.008  0.026 0.061  0.433 0.017  0.009 0.059  2.012  0.002  42.07  2.04  2.981 0.160  53.64 2.83  2.8  4.571 0.005  0.022 0.029  0.278 0.016  0.005 0.056  1.289  0.002  28.37  3.92  3.098 0.087  55.70^1.54  3  4.142 0.009  0.019 0.040  0.171 0.020  0.003 0.044  0.792  0.001  19.64  5.97  3.190 0.054  57.33 0.96  3.2  4.075 0.006  0.020 0.028  0.240 0.013  0.002 0.060  1.116  0.001  14.39  7.29  3.364 0.049  60.40 0.86  3.4  3.915 0.008  0.020 0.017  0.318 0.014  0.002 0.035  1.479  0.001  11.65  14.18  3.378 0.034  60.66 0.60  3.6  3.854 0.004  0.022 0.014  0.634 0.013  0.002 0.035  2.95  0.002  8.52  28.04  3.470 0.023  62.27 0.40  3.8  3.925 0.006  0.036 0.012  1.467 0.013  0.002 0.029  6.84  0.005  9.84  16.59  3.472 0.031  62.31^0.54  4  3.965 0.005  0.037 0.020  1.318 0.013  0.002 0.032  6.146  0.005  10.09  13.05  3.485 0.029  62.54 0.51  4.2  4.031 0.005  0.037 0.022  1.193 0.013  0.003 0.033  5.557  0.005  10.59  7.58  3.485 0.031  62.54 0.55  PL31, biotite, J 0.009018+0.000012, volume 39ArK = 130.41 x 10^ - 10 cm3, integrated age 93.38+0.81 Ma (2 - s)  2  274.6177±0.0561  0.9733±0.0821  8.8057±0.2855  0.4318±0.0638  9.396  0.213  42.41  0.2  2.3  98.7613 0.0114  0.3783 0.0605  3.2244 0.2508  0.1332 0.0449  6.827  0.078  37.39  1.21  60.511^1.930  785.63 20.32  2.6  13.6930 0.0068  0.0681 0.0334  2.9117 0.0707  0.0197 0.0494  8.277  0.011  34.77  4.11  8.211^0.295  128.87 4.47  2.9  5.7218 0.0064  0.0905 0.0240  5.0312 0.0208  0.0080 0.0344  15.669  0.017  22.54  9.1  4.028 0.088  64.38^1.38  3.2  5.9371 0.0105  0.1665 0.0254  6.3751 0.0202  0.0063 0.0791  20.134  0.035  10.58  12.36  4.978 0.158  79.22 2.46  3.5  5.6269 0.0101  0.1522 0.0310  6.7723 0.0202  0.0062 0.0450  21.479  0.032  10.86  15.07  4.746 0.099  75.61^1.55  161.258±12.40 , 1619.73±82.23  187  Table III-C^Ar/Ar Data Laser Power % 3.8  Isotope Ratios 40Ar/39Ar  38Ar/39Ar  37Ar/39Ar  36Ar/39Ar  Ca/K  Cl/K  %40Ar atm  f 39Ar  40Ar*/39ArK  Age  5.2902 0.0087  0.2459 0.0111  8.3815 0.0148  0.0056 0.0322  26.857  0.054  6.5  36.07  4.841^0.070  77.09^1.09  4.1  5.7014 0.0088  0.1295 0.0343  5.8559 0.0181  0.0059 0.0431  18.409  0.026  9.88  10.91  4.754 0.089  75.74^1.39  4.5  5.8040 0.0115  0.1158 0.0424  4.4587 0.0235  0.0054 0.1013  13.898  0.023  10.58  10.97  4.803 0.174  76.50 2.71 120.26±13.67  SS3, biotite, J = 0.010151+0.000012, volume 39ArK = 627.81 x 10'40 cm3, integrated age 71.71+0.44 Ma (2 -s) 2  21.684±0.007  0.097±0.040  0.193±0.038  0.049±0.055  0.799  0.017  66.96  0.75  6.790±0.798  2.2  9.858 0.015  0.086 0.030  0.246 0.030  0.022 0.040  1.049  0.016  64.63  2.37  3.339 0.272  60.13^4.81  2.4  5.599 0.010  0.056 0.024  0.141 0.018  0.007 0.052  0.604  0.009  33.87  8.83  3.611 0.110  64.95^1.95  2.6  5.567 0.007  0.046 0.021  0.143 0.015  0.005 0.029  0.613  0.007  28.1  17.39  3.937 0.057  70.70^1.01  2.8  5.560 0.008  0.045 0.024  0.212 0.018  0.005 0.031  0.909  0.007  26.21  12.85  4.025 0.058  72.24 1.03  3  5.373 0.005  0.040 0.025  0.348 0.014  0.005 0.034  1.526  0.006  23.07  16.32  4.065 0.051  72.96 0.90  3.2  5.148 0.006  0.036 0.021  0.383 0.016  0.004 0.037  1.68  0.005  20.15  15.16  4.038 0.051  72.48 0.89  3.4  5.216 0.005  0.039 0.029  0.378 0.013  0.004 0.041  1.658  0.006  20.76  11.99  4.050 0.054  72.69 0.95  3.8  5.217 0.005  0.042 0.023  0.413 0.013  0.004 0.037  1.81  0.006  20.55  10.15  4.053 0.049  72.73 0.86  4.2  5.355 0.005  0.049 0.044  0.892 0.014  0.005 0.053  3.941  0.008  20.4  4.2  4.087 0.077  73.34^1.35  Neutron flux monitors: 28.02 Ma FCs (Ronne et al., 1998) Isotope production ratios: (40Ar/39A0K-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).  188  

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