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Architecture of the Silurian sedimentary cover sequence in the Cadia porphyry Au-Cu district, NSW, Australia.. 2008

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  ARCHITECTURE OF THE SILURIAN SEDIMENTARY COVER SEQUENCE IN THE CADIA PORPHYRY AU-CU DISTRICT, NSW, AUSTRALIA: IMPLICATIONS FOR POST-MINERAL DEFORMATION  by MALISSA WASHBURN B.S. University of Maine, 2006  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE STUDIES (Geologic Sciences)  UNIVERSITY OF BRITISH COLUMBIA (Vancouver)  July, 2008  © Malissa Washburn, 2008  ii Abstract  Alkalic porphyry style Au-Cu deposits of the Cadia district are associated with Late-Ordovician monzonite intrusions, which were emplaced during the final phase of Macquarie Arc magmatism at the end of the Benambran Orogeny.  N-striking faults, including the curviplanar, northerly striking, moderately west-dipping basement thrust faults of the Cadiangullong system, developed early in the district history.  NE-striking faults formed during rifting in the late Silurian.  Subsequent E-W directed Siluro- Devonian extension followed by regional E-W shortening during the Devonian Tabberabberan Orogeny dismembered these intrusions, thereby superposing different levels porphyry Au-Cu systems as well as the host stratigraphy. During the late Silurian, the partially exhumed porphyry systems were buried beneath the Waugoola Group sedimentary cover sequence, which is generally preserved in the footwall of the Cadiangullong thrust fault system.  The Waugoola Group is a typical rift-sag sequence, deposited initially in local fault-bounded basins which then transitioned to a gradually shallowing marine environment as local topography was overwhelmed.  Basin geometry was controlled by pre-existing basement structures, which were subsequently inverted during the Devonian Tabberabberan Orogeny, offsetting the unconformity by up to 300m vertically.  In the Waugoola Group cover, this shortening was accommodated via a complex network of minor detachments that strike parallel to major underlying basement faults.  For this reason, faults and folds measured at the surface in the sedimentary cover can be used as a predictive tool to infer basement structures at depth.  iii Table of Contents  Abstract ..................................................................................................  ii Table of Contents ................................................................................ iii List of Tables .......................................................................................  vi List of Figures ..................................................................................... vii Acknowledgements ............................................................................ xii Dedication ............................................................................................ xiv Chapter One: Introduction ...............................................................1 THESIS OVERVIEW .........................................................................3 Methodology ...................................................................................4 REGIONAL GEOLOGY ....................................................................5 The Tasmanides and the Lachlan Tectonic Cycle ......................6 The Lachlan Fold Belt .................................................................11 The Macquarie Arc......................................................................14 THE CADIA DISTRICT...................................................................17 Chapter Two:  Stratigraphic Framework..................................19 INTRODUCTION..............................................................................19 ORDOVICIAN BASEMENT ...........................................................22 Weemalla Formation ...................................................................22 Forest Reefs Volcanics .................................................................22 Cadia Intrusive Complex ............................................................24  iv SILURIAN COVER...........................................................................24 Basal Units ....................................................................................26 LIMESTONE...........................................................................29 BOULDER CONGLOMERATE.............................................31 RED SILTSTONE ...................................................................31 Lower Siltstone-Dominant Succession .......................................34 Upper Sandstone-Dominant Succession ....................................37 INTERPRETATIONS .......................................................................39 Paleogeography and Basin Evolution.........................................39 Regional Correlations ..................................................................47 IMPLICATIONS ...............................................................................50 Chapter Three: Structural Relationships in the Cadia District .......................................................................................55 INTRODUCTION..............................................................................55 REGIONAL AND DISTRICT SCALE STRUCTURE..................56 Regional Structure .......................................................................56 District-Scale Structural Trends ................................................59 N-STRIKING FAULTS...........................................................65 NE-STRIKING FAULTS ........................................................66 STRUCTURES IN THE SILURIAN WAUGOOLA GROUP ......67 Intra-cover Deformation .............................................................83 FAULT REACTIVATION HISTORY ...........................................90 Boulder Conglomerate.................................................................92  v Sharps Ridge.................................................................................92 Waugoola Group Geometry........................................................94 SUMMARRY AND CONCLUSIONS .............................................96 Hierarchy of Faults ......................................................................96 Basement-Cover Interaction .....................................................101 Basin Inversion...........................................................................101 Chapter Four: Conclusions ...........................................................104 INTRODUCTION............................................................................104 CONCLUSIONS ..............................................................................105 IMPLICATIONS .............................................................................108 Post-mineral Deformation and Using Structure in the Cover Sequence to Understand the Basement ...................................................109 FUTURE WORK .............................................................................111 References............................................................................................113 Appendices ..........................................................................................126 APPENDIX I: Bedding Measurements..........................................126 APPENDIX II: Fault Measurements .............................................147 APPENDIX III: Drillcore Logs ......................................................157      vi List of Tables   1.1          The Lachlan Tectonic Cycle .................................................................... 9  3.1          Basement Fault Fabrics in the Cadia District .........................................62                   vii List of Figures   1.1          Map of the Tasmanides.............................................................................7  1.2          Map of the Lachlan Fold Belt .................................................................12  1.3          Map of the Macquarie Arc......................................................................16  2.1          Simplified map and stratigraphic column of the Cadia District .............21  2.2          Photographic plate of macrofossils from the sedimentary cover rocks .....................................................................................25  2.3          Waugoola Group stratigraphy and surface map......................................27  2.4          Basal unit distribution map .....................................................................28  2.5          Photographs of limestone and calcirudite ...............................................30  2.6          Photographs of boulder conglomerate ....................................................32  2.7          Photographs of red siltstone....................................................................33  viii  2.8          Photographs of siltstone..........................................................................35  2.9          Photographs of arkose ............................................................................36  2.10         Photographs of sandstone ......................................................................38  2.11          Interpretive stratigraphic cross-sections of the Waugoola Group on Sharps Ridge ..................................................................................41  2.12          Interpretive depiction of stratigraphic relationships in the Waugoola Group on the southern wall of the Cadia Hill pit .........42  2.13          Cross-section and paleogeographic interpretation of the Waugoola Group across Cadia Hill and Cadia East ................44  2.14          Diagram showing idealized rift-sag sequence features.........................46  2.15          Regional tectonic controls of evolution of the Cadia District...............51  2.16          Map showing the stratigraphic position of the Forest Reefs Volcanics at the unconformity with overlying Waugoola Group sedimentary rocks..............................................52  ix  3.1          Regional geologic map ...........................................................................58  3.2          Generalized geology map of the Cadia District ......................................61  3.3          Cross-section across mineral deposits in the Cadia District ...................63  3.4          Annotated aerial photograph of Cadia Hill and Cadia East ....................64  3.5          Structural domain map of Cadia Hill and Cadia East .............................68  3.6          Map of the Waugoola Group with bedding orientations ........................70  3.7          Reference map for locations of photographs used in chapter three figures.......................................................................72  3.8          Panoramic photograph of the southern wall of Cadia Hill pit showing relationships between basement and cover faults ......73  3.9          Photographs of unconformity features on the southern wall of Cadia Hill pit .............................................................................75    x 3.10         Panoramic photograph of the eastern wall of Cadia Hill pit showing structural relationships on Sharps Ridge .........................76  3.11         Photographs of faults from the eastern wall of Cadia Hill pit ...............77  3.12          Faults and folds at the unconformity on the southern slope of Sharps Ridge..............................................................................79  3.13          Detailed field sketch and photograph showing faults and folds related to the Cat Fault...................................................................81  3.14          Photographs of open folds related to the Copper Gully Fault ..............82  3.15          Photographs illustrating bedding plane parallel slip.............................84  3.16          Detailed field sketches and panoramic photographs of folds and thrust faults in sandstone.........................................................85  3.17           Photographs and stereonets of tight fault-related folds in siltstone related to the Gibb Fault ................................................................87  3.18          Photographs and stereonets of fault related folds in Cadia East...........88   xi 3.19          Photograph of flaser bedded siltstone from drillcore............................89  3.20          Map showing spatial distribution of basal conglomerate .....................93  3.21          Cross-section showing interaction of basement faults with faults and folds in the cover sequence ...........................................95  3.22          Interpretive map-view timeslices showing the structural evolution of the Cadia District.......................................................97  3.23          Tectonic model for rifting and basin inversion...................................100  3.24          Global basin inversion models............................................................103            xii Acknowledgements    This thesis would not have been possible without the intellectual, logistical, and emotional support of many people.  First and foremost, I would like to thank my primary advisor, Dick Tosdal for setting up this project, traveling back and forth from Vancouver to Australia to make sure I was on track, and making many valuable suggestions both in the field and during the editing process.  Thanks to Dick’s input, I have had the opportunity to grow as a geologist, and as a writer.  Ken Hickey and Lori Kennedy, my other committee members, also offered valuable criticism at my defence that has enabled me to improve the presentation of my research, and for that I am grateful. Anthony Harris from CODES at the University of Tasmania has also provided invaluable insight into the district-scale geology of the Cadia Valley and where this project fits in to the bigger picture.  Even at the beginning when no one else thought the unaltered and unmineralized rocks at the surface mattered, Anthony supplied logistical support and scientific encouragement to an often confused student very far from home. Many Thanks to John Holliday, Ian Tedder, Dean Collett, Paul Dunham, Colin MacMillan, Matt Hatzl, Mark Aheimer, Robyn Ransley, Lal Mendis, Adam Marcinek, and Dougal Munro, all with Newcrest Mining LTD. for making mapping possible and safe, helping with the database and other technical support issues, moving core boxes, and asking lots of insightful questions.  Thanks especially to Caroline Hassal and her parents, Rosemary and Frank, for providing lodging, transportation, and entertainment in Spring Hill, and introducing me to cordial, pavlova, and Brafords. Thanks to Dave Cooke from CODES for discussions in Hobart about regional tectonics, and to Ian Percival, for his amazing knowledge of fossils.  Arne Toma and Ken  xiii Hickey at MDRU deserve a great deal of appreciation for technical support with Map Publisher, the plotter, and countless other computer-related inquiries.  Thanks to the SEG Canada Foundation Award for funding transportation to and from Australia for my second field season.  I would also like to thank my professors from the University of Maine for getting me started in Geology, instilling in me a healthy dose of skepticism, and preparing me, as best they could, for grad school.  In particular, Scott Johnson, Peter Koons, and Marty Yates were instrumental in guiding me toward this point in my career. Personally, if it hadn’t been for the emotional support of my Dad, and my friends Liz, Sara, Shawn, and Bobby, I might have broken down a long time ago, and would have never realized my potential as a geologist and a human being.  Thanks for being there fore me despite the growing physical distance between us.  Thanks also to my fellow grad students at UBC for conversation, companionship, and countless wine- tastings in the basement.  Last, but certainly not least, much gratitude to my husband Wes Groome, for comforting me thought the difficult parts, laughing with me though the fun parts and inspiring me to ride the rollercoaster to the end.  If it weren’t for Wes’ advice, as a geologist, editor, and friend, I wouldn’t have been able to come this far in such a short time.        xiv Dedication     To my mother  Chapter One: Introduction  To better guide resource development, from exploration to mining, in regions with complex geologic histories, it is important to understand the nature of pre-, syn-, and post-mineralization tectonism.  Ground preparation prior to mineralization may enable transport and localization of ore-forming fluids via several mechanisms, including the juxtaposition of thermally, chemically, or rheologically disparate materials, the formation of interconnected fracture networks that act as fluid flow pathways, and the development of permeability barriers (e.g. Bierlein et al., 2002; Jaques et al., 2002).  During mineralization, active deformation may assist the movement of fluids through the system and concentrate ore in locally dilatant sites as the transient permeability structure of the host rock changes (Tosdal and Richards, 2001).  Syn-mineral deformation may also result in active fluid transport along structures via seismogenic fault-valve action (seismic pumping) due to regional changes in the stress regime (e.g. Jaques et al., 2002). Post- mineral deformation can dismember the orebody or provide new pathways for subsequent remobilization of ore fluids (e.g. Dilles et al., 1991; Willis and Tosdal, 1992).  In relation to porphyry systems, which form at relatively shallow depths (1-3 km), post-mineral uplift and erosion may remove part or all of the orebody (Camus, 2003; Cooke et al., 2005).  However, a transition to an extensional regime following mineralization may result in burial of the deposit and enhance the possibility of preservation (Sillitoe, 2000). Australia is an important producer of copper and gold worldwide, including multi- million ounce porphyry Au-Cu deposits within the Paleozoic Tasman Orogenic system (Jaques et al., 2002; Cooke et al., 2007).  In the Lachlan Orogen, a subset of the 1  Tasmanides, porphyry and related epithermal and skarn deposits formed during the late Ordovician to early Silurian in subduction-related volcanic arc and arc-associated host rocks that were localized by long-lived, large-scale crustal structures active during the Benambran Orogeny (e.g. Cooke et el., 2007; Glen et al., 2007c).  Major mineral districts in the eastern part of the Lachlan Orogen include Cadia (the focus of this study), Cowal, Copper Hill, Goonumbla, Peak Hill and Gidgninbung, all of which formed during Ordovician to Early Silurian Macquarie Arc magmatism.  Multiple episodes of subsequent tectonic activity resulted in polydeformation and complex structural relationships.  Not only is placing these major mineral deposits into a tectonic context important for regional exploration, comparative district- and deposit-scale studies enable more complete tectonic models to be constructed for the evolution and growth of the Australian continent. Alkalic porphyry deposits and skarns of the Cadia District have been a significant source of Cu, Au, and Fe for Australia since the 1850’s (Holliday et al., 2002). Currently, the Cadia District is one of the largest alkalic porphyry deposits worldwide in terms of contained gold (Wilson et al., 2004; Cooke et al., 2004; Cooke et al, 2007).  Pre- mine resources of the Cadia district were estimated at 585 t Au and 2.35 Mt Cu (Holliday et al., 2002).  The intrusive history, fluid evolution, and alteration systems of the district have been studied extensively, and are well understood to date (Holliday et al., 2002; Wilson et al., 2003; Forster et al., 2004; Cooke et al., 2006b; Wilson et al., 2007a; Wilson et al., 2007b; Squire and Crawford, 2007).  Such ore processes occur over timescales that are relatively short (10s to 100s of thousands of years) compared to regional tectonic processes (millions of years). 2  On a global scale, giant porphyry deposits have been recognized to cluster in orogen-scale mineral provinces, which suggests that they are localized by orogen-scale geodynamic processes (e.g. Clark, 1995; Cooke et al, 2005).  In older orogens, such as the late Ordovician-early Silurian Benambran Orogeny, the preservation potential of porphyry deposits is directly related to the post-mineral history of uplift, erosion, and orogenesis (Cooke et al., 2005).  Therefore, it is critical to put the mineralizing system in a temporal and spatial context in order to develop a complete, holistic model to explain present day ore distribution.  THESIS OVERVIEW  The aims of this thesis are to describe the Silurian Waugoola Group sedimentary cover sequence in the Cadia District and characterize the post-mineral deformation.  This structural analysis is then incorporated into district-scale tectonic models for the history of orebody formation and dismemberment.  Furthermore, reconstruction of the Silurian succession and recognition of the hierarchy of faults is essential to the on-going project attempting to reconstruct the syn-mineralization Ordovician architecture of the district. This project is part of the larger ‘district-to-deposit-scale structural and geochemical study of the Cadia porphyry Au-Cu deposits’ managed by CODES ARC Centre of Excellence in Ore Deposits. Like other porphyry deposits of the Macquarie Arc, mineralization in the Cadia district occurred at the end of the Benambran Orogeny (~443-438 Ma).  At least three subsequent deformation events have been regionally recognized in the Lachlan Fold Belt; 3  these include the Bindian (Late Silurian), Tabberabberan (Early Devonian), and Kanimblan (Early Carboniferous) Orogenies.  Because the Waugoola Group was deposited in the middle Silurian (~424-426 Ma), after ore formation and the cessation of Benambran deformation, but prior to later tectonic events, it preserves a record of post- mineral deformation.  This can then be used to geometrically constrain district-scale reconstructions.  Greater understanding of these structural relationships will also be crucial for developing exploration models in and around the Cadia East deposit, and also for constructing geotechnical and hydrologic models as development and production commences. The remainder of Chapter One is a discussion of regional geology.  In Chapter two of this thesis, a stratigraphic succession for the Waugoola Group at Cadia East is presented in order to form a basis for structural analysis in Chapter Three.  Finally, the regional significance of deformation recorded in the Waugoola cover sequence, and the implications of orebody dismemberment will be discussed in light of the current models for the tectonic history of the Cadia District in Chapter Four.  Methodology  Mapping of the sedimentary cover sequence at Cadia East was undertaken from August to October, 2006, and May to August, 2007, in order to constrain the character and scale of faulting and folding in different geographic areas and stratigraphic horizons. Detailed field sketches of outcrops along the Cadia Hill Access Road, in Copper Gully, and from the southern and eastern walls of Cadia Hill pit were used to understand 4  structural relationships at the 1:200 scale.  Strike and dip measurements of bedding and faults were taken using a Brunton compass and geographically referenced with a GPS for compilation into a 1:5,000 map of the sedimentary cover rocks at Cadia East and the surrounding areas.  Due to safety restrictions in Cadia Hill Pit, measurements from pit walls were estimated from a distance of at least 5m.  Surface and pit wall mapping covered an area of roughly 4km2. Lithological data was also gathered by producing graphic logs of the cover rocks in drillcore.  Because drillcore was not oriented, structures were noted but not measured. Magnitude of fault offsets in drillcore is also poorly constrained.  In combination with surface measurements, drillcore data was used in producing interpretive cross-sections through the sedimentary cover rocks.  This was combined with pre-existing datasets for faults in the Ordovician basement rocks provided by Newcrest Mining Ltd, constrained by drillcore and geotechnical mapping in Cadia Hill Pit.  Spatial information was organized in MapInfo, and was subsequently exported to Adobe Illustrator using Map Publisher for editing.  REGIONAL GEOLOGY  Southeastern Australia has experienced multiple orogenic events from the Late Proterozoic to the late Mesozoic (Glen, 2005; Cawood, 2005; Gray et al., 2006).  In this region, multiple cycles of compression and extension associated with the growth of the Australian continent have been identified, resulting in a complex regional geologic history.  The Cadia District is located in the Macquarie Arc, a late Ordovician volcanic 5  island arc in the eastern Lachlan Fold Belt.  Mineralization occurred ~440 Ma, and the age of the unconformably overlying Waugoola Group sedimentary cover sequence is ~425 Ma.  Regional variations in lithology and older structural fabrics have locally influenced deformation at the district-scale.  In order to understand the effect of these events on the Cadia District and the resulting associations between structure and ore distribution, it is necessary to review the regional tectonic history, from continent- to district-scale.  The Tasmanides and the Lachlan Tectonic Cycle  The Tasmanides are a long-lived, composite orogenic belt that formed through episodic accretion to the Gondwanan margin of eastern Australia, commencing in the early Paleozoic with the breakup of Rodinia and concluding in the Early Mesozoic with the cratonization of the western portions of the New England Orogen (Figure 1.1; Gray and Foster, 2004).  The eastern margin of the Australian Craton approximately follows the Tasman Line, an irregular north-south “zig-zag” line that bisects Australia, and marks the eastern margin of the Precambrian basement (e.g. Hill, 1951; Li and Powell, 2001; Direen and Crawford, 2003). The Tasmanides have been divided into six major structural belts. The Delamerian Orogen to the southwest, the Lachlan Fold Belt to the southeast, the Thompson Fold Belt to the northwest, and to the northeast, the Hodgkinson-Broken River Fold Belt, are all separated from the New England Fold Belt by the Sydney-Bowen Basin 6 NSW QLD TAS NT SA VIC ACT Ta sm an  Li ne CADIA Lachlan Fold Belt km 0 400200 N Sydney Proterozoic Craton Adelaide Hobart Melbourne Delamerian Fold Belt Thompson Fold Belt New England Fold Belt Sy d n ey -B o w en  B as in Hodgskin-Broken River Fold Belt THE TASMANIDES Figure 1.1:  The Tasmanides are a long-lived composite orogenic belt that composes much of eastern Australia. Cadia is located in the Lachlan Fold Belt.  Map of the Tasmanides modified from Scheibner and Basden, 1996; structural form lines after Gray and Foster, 2004. 7  (Scheibner and Veevers, 2000).  These orogenic zones generally young toward the east, and represent separate episodes of orogenesis (Gray and Foster, 2004; Glen, 2005). The timing and geometry of terrane assembly in the Tasmanides has been described by Glen (2005) in terms of three major tectonic cycles: the Delamerian Cycle (830-490 Ma), the Lachlan Cycle (490-320 Ma), and the Hunter-Bowen Cycle (320-230 Ma).  The Lachlan Cycle is further subdivided into the Benambran (~443-430 Ma), Bindian (~420 Ma), Tabberabberan (~380 Ma), and Kanimblan Orogenies (~340) (Glen, 2005).  The Lachlan tectonic cycle had the greatest effect on the Cadia region, and will be discussed in greater detail below (Table 1.1). Convergence associated with the early phase of the Benambran Orogeny marks the beginning of the Lachlan Tectonic Cycle and coincides with the end of the Delamerian Cycle (Glen, 2005). The collisional stage of the Benambran Orogeny in the Lachlan Fold Belt occurred in two distinct phases.  The first at ~443 Ma resulted in folds, thrusts, cleavage formation and some strike-slip faults deforming Ordovician turbidites and black shale due to E-W shortening (Glen, 2005).  By this time, magmatism in the Macquarie Arc had ceased and arc rocks were thrust over and accreted onto barckarc turbidites (Glen, 2005).  This compressional phase was followed by a period of extension and basin formation in the earliest Silurian (Glen et al., 2004).  The second collisional phase of the Benambran Orogeny lasted from ~433-430 Ma (Glen, 2005).  During this phase, oblique thrusting in the Central Lachlan and translation of the Macquarie Arc to the southwest was accompanied by uplift and thrusting of turbidites as well as portions of the arc itself (VandenBerg, 1999; Glen, 2005).  Emplacement of syn-tectonic granites also occurred at this time (VandenBerg, 1999). 8 B IN D IA N  O R O G E N Y B E N A M B R A N  O R O G E N Y O R O G E N Y T A B B E R A B B E R A N MACQUARIE ARC MAGMATISM T H E  L A C H L A N  C Y C L E  ( 4 9 0 -3 2 0  M a ) D E L A M E R IA N  C Y C L E  ( 8 3 0 -4 9 0  M a ) H U N T E R -B O W E N  C Y C L E  ( 3 2 0 -2 3 0  M a ) O R O G E N Y K A N IM B L A N M a c q u a ri e  A rc M in e ra l  D e p o s it s ARC DISMEMBERMENT C A D IA  D IS T R IC T  H O S T  R O C K S W A U G O O L A  G R O U P C a d ia  I n tr u s io n s &  M in e ra li z a ti o n 4 0 0 4 2 5 4 5 0 4 7 5 3 7 5 ORDOVICIANSILURIANDEVONIAN 3 5 0 CARBONIFEROUS E -W  S h o rt e n in g E -W  S h o rt e n in g D e x tr a l T ra n s p re s s io n R if ti n g R if ti n g B a c k -a rc  B a s in  E x te n s io n S tr ik e -S li p  T ra n s la ti o n E -W  S h o rt e n in g R if ti n g N E -S W  S h o rt e n in g L a c h la n  F o ld  B e lt M a c q u a ri e A rc C a d ia  D is tr ic t Ta b le  1 .1 : Ti m in g  o f te ct o n ic  e ve n ts  in  t h e La ch la n  C yc le , t h e M ac q u ar ie  A rc  a n d  d ep o si ti o n  a n d  m in er al iz at io n  in  t h e C ad ia  D is tr ic t.  A g es  co m p ile d  fr o m  G le n  et  a l.,  2 00 7;  H ar ri s, in  p re p , P er ci va l a n d  G le n , 2 00 7;  R ic ka rd s et  a l.,  2 00 1;  P o g so n  an d  W at ki n s, 19 98 ; G le n , 2 00 5,  a n d  re fe re n ce s th er ei n . 9  The Bindian Orogeny (~420-410 Ma) resulted in translation and thrusting of the central Lachlan Orogen to the south-southeast (Willman et al., 2002).  This translation was facilitated along major bounding fault systems that separate the central Lachlan from the western and eastern subprovinces.  Throughout the Tasmanides, Bindian orogenesis marked a major period of strike-slip deformation. Late Silurian to Late Devonian arc magmatism related to a west-dipping subduction zone formed as a result of Tabberabberan convergence in the New England Orogen (Offler and Gamble, 2002).  The Lachlan Orogen, in the backarc setting during convergence of the Tabberabberan Cycle, experienced rift or transtensional basin formation and granite emplacement (Reed et al., 2002; Spaggiari et al., 2004). Tabberabberan deformation was caused by collision of the intra-oceanic arc generated during the previous convergent phase and accretion to the continental margin in the Northern New England Orogen.  Inversion of basins in the Lachlan Orogen during the middle Devonian characterizes the deformation (Hood and Durney, 2002; Willman et al., 2002).  In the eastern Lachlan Orogen, shortening at ~380 Ma was NE-SW directed (Miller et al., 2001; Watson and Gray, 2001). The final stage of Tabberabberan contraction formed conjugate NE- and NW-trending brittle faults that offset major plutons in order to partition E-W shortening around resistant plugs of newly cooled granites (Glen, 1992).  The Kanimblan Cycle began with rifting in the Early to Middle Devonian.  At ~340Ma, Kanimblan Orogenesis commenced, and was the last major deformation to affect the Lachlan Fold Belt.  Shortening was predominantly E-W, with minor strike-slip separation occurring locally (Glen, 2005).  In the eastern Lachlan Orogen, N- striking 10  faults were reactivated and accompanied by folds and cleavage development as the basins were inverted (Glen, 2005).  The Lachlan Fold Belt  The Lachlan Fold Belt extends from southern Queensland to southeastern Tasmania, and underlies most of New South Wales and Victoria.  In general, the Lachlan Fold Belt is thought to have formed during episodic accretion of deformed oceanic sequences, volcanic arcs and arc-related rocks, and microcontinents to the Gondwana margin during the Lachlan Tectonic Cycle as described above (e.g. Bierlein et al., 2002; Gray and Foster, 2004; Glen, 2005).  In general, the Lachlan Fold Belt is composed of low-metamorphic-grade turbidites that were deposited in a back-arc environment and deformed in three separate thrust systems.  Local high-T/low-P metamorphic complexes and island arcs are also present (Figure 1.2; Gray et al., 2006). Turbidites are the dominant rock type across the orogen, suggesting an oceanic setting for the whole of the Lachlan Fold Belt (Gray and Foster, 2004). This turbidite package, along with associated accreted rocks (including the Ordovician Macquarie Arc), was repeatedly thickened by folding and thrusting, dismembered by strike-slip faulting, thinned by extensional faulting, intruded by plutons, and eventually merged through stepwise accretion (Coney, 1992).  The crustal architecture of the Lachlan Orogen includes both thin-skinned (multiple detachments producing a leading imbricate fan system) and thick-skinned (major faults extending to the Moho) features, with a transition 11 N SWQ LD SA V IC TA S TH E LA C H LA N  F O LD  B EL T Sy d n ey C EN TR A L EA ST ER N W ES TE R N 0 2 5 0 5 0 0 La ch la n  F o ld  B el t Su b d iv is io n s Ta sm an  L in e St at e B o u n d ar ie s St ru ct u ra l F ab ri c C ad ia  D is tr ic t C am b ri an  T u rb id it es O rd ov ic ia n  T u rb id it es W ag g a- O m eo  M et am o rp h ic  B el t M ac q u ar ie  A rc Se d im en ta ry  C ov er  S eq u en ce G ra n it e M es oz o ic -C ai n oz o ic  C ov er LE G EN D N Fi g u re  1 .2 : Si m p lif ie d  m ap  o f t h e La ch la n  F o ld  B el t, sh o w in g  s u b d iv i- si o n s an d  g en er al iz ed  g eo lo g y.   T h e C ad ia  D is tr ic t is  lo ca te d  in  t h e M aq u ar ie  A rc  o f t h e Ea st er n  L ac h la n  F o ld  B el t.  M o d ifi ed  fr o m  G ra y an d  Fo st er , 2 00 4. 12  from western thin-skinned tectonism to eastern thick-skinned tectonism (Gray et al., 2006). The Lachlan Fold Belt, assembled from west to east via roughly N-striking regional structures, can be subdivided into three structural zones: the western, central, and eastern subprovinces (Figure 1.2). The distinction between these zones has been defined based on geochronology of deformation and major structural breaks (Gray and Foster, 2004; Glen, 2005; Gray et al., 2006).  In general, the western subprovince consists of tightly folded turbidites and low grade metamorphosed ophiolites, the central subprovince is dominated by a high-grade metamorphic core complex and an accretionary complex, and the eastern subprovince is a folded and faulted turbidite package and an Ordovician island arc system (Gray and Cull, 1992).  Early Carboniferous sedimentary rocks are found in localized basins throughout the Lachlan Fold Belt, and Siluro-Devonian granites are also present in all zones of the Lachlan Fold Belt (Suppel et al., 1998; Coney, 1992). Metallogenically, the western Lachlan is rich in orogenic lode gold deposits, whereas the central Lachlan contains a more diverse range of mineral deposit types, including intrusive-hosted, volcanogenic massive sulphide, and epigenetic sediment- hosted gold and base metal deposits (Bierlein et al., 2002).  Porphyry-style mineralization in the Lachlan Orogen is restricted to the eastern portion, particularly the Ordovician Macquarie Arc, although volcanic-hosted massive sulphides, sediment-hosted base metals, and some orogenic lode gold deposits are also present in the eastern Lachlan (Bierlein et al., 2002).  These deposits are thought to be related to slab rollback following seamount collision at ~455 Ma (Squire and Miller, 2003). 13  Deformation in the western subprovince commenced at ~455 Ma, characterized by mostly west-dipping thrust faults and west vergent chevron folds (Gray and Foster, 1998; Foster et al., 1998; Squire and Miller, 2003; Gray and Foster, 2004).   Deformation migrated to the east at ~440 Ma and continued throughout the Lachlan Belt into the Silurian, with east-west shortening, sinistral wrenching, and south-east directed thrusting in the western subprovince, and east-west shortening, south-directed thrusting, and strike- slip faulting in the central and eastern subprovinces (Foster et al., 1999; Miller et al., 2001).  In the central and eastern subprovinces, deformation was accompanied by the largest and final outpouring of shoshonitic magma in the Macquarie Arc at ~440 Ma (Perkins et al., 1995; Squire and Miller, 2003; Glen et al., 2007a; Glen et al., 2007b). Much of the mineralized centers in the Lachlan Orogen formed at this time (Squire, 2001; Miller and Wilson, 2002).   The Macquarie Arc  The Macquarie Arc is a long-lived Ordovician volcanic arc composed of predominantly subaqueous volcanic rocks and associated shallow-level intrusions with a calc-alkalic to shoshonitic affinity (e.g. Cooke et al., 2007).   Magmatic activity in the Macquarie Arc commenced in the Early Ordovician at the boundary between the Australian and the proto-Pacific plates (Glen et al., 1998; Glen et al., 2007b; Meffre et al., 2007).  Episodic evolution of the arc continued for ~50 Ma until magmatism ceased in the early Silurian (Glen et al., 2007b).  The Macquarie Arc formed over a west-dipping subducting slab that underwent slab rollback, resulting in eastward migration of the 14  magmatic center preserved as a general east-younging of the arc rocks (Percival and Glen, 2007).  Turbidites and other arc-related sedimentary rocks are intercalated with the volcanic rocks (Squire and McPhie, 2007). The Macquarie Arc is separated into three distinct structural belts, although it is probable that these three belts formed together as part of one arc and were subsequently disrupted during rifting in the Silurian and Devonian (Figure 1.3; Percival and Glen, 2007).  From west to east, and generally youngest to oldest, these belts are the Junnee- Narromine Volcanic Belt, the Molong Volcanic Belt, and the Rockley-Gulgong Volcanic Belt.  The Kiandra Volcanic Belt is a fourth structural division of the Macquarie Arc that occurs to the south near the Victoria-New South Wales border, and may represent a portion of the Junee-Narromine belt that was dismembered during strike-slip faulting (Glen et al., 2007b; Percival and Glen, 2007). A number of Au and Cu deposits are associated with Macquarie Arc magmatism. Porphyry deposits of the Macquarie Arc are aligned along a northwest striking trend, known as the Lachlan Transverse Zone (LTZ).  The intersection of this regional- to deposit-scale fabric with N-trending, arc-parallel faults may have localized mineralization (Glen and Walshe, 1999; Finlayson et al., 2002).  Seismic imagining has shown that these lineaments are zones of weakness in the lithosphere that may have been long-lived zones of reactivation (Glen and Walshe, 1999; Finlayson et al., 2002).     15 ORANGE VO LC AN IC  JU N EE  - N A RR O M IN E BE LT M O LO N G V O LC A N IC BE LT RO C KL EY G U LG O N G VO LC A N IC BE LT Narromine Northparkes Cowal CADIA Copper Hill Comobella THE MACQUARIE ARC LTZ KI A N D RA VO LC A N IC BE LT SYDNEY CANBERRA QLD NSW NSW VIC ACT Marsden Gidgninbung Swatchfield 0 50 100 km N Maquarie Arc Volcanic Rocks Lachlan Transverse Zone Cities Mineral Deposits State Boundaries LEGEND Figure 1.3:  Mineral deposits and structural belts of the Macquarie Arc.  Volcanic rocks associated with arc volcanism during the late Ordovician to early Silurian were accreted to the proto-Australian margin during the Benambran Orogeny and subsequently dismembered during rifting.  The Cadia District is located in the Molong Volcanic Belt, and occurrs on the Lachlan Transverse Zone (LTZ).  Modified from Holliday et al., 2002 and Glen et al., 2007. 16  THE CADIA DISTRICT  Copper was first discovered in the Cadia District in 1851. By the mid 1860’s mining was underway at the West Cadia and White Engine deposits, and Cadia Village became a major settlement in New South Wales.  Gold was discovered in the early 1870’s.  During the world wars, the Cadia district saw a period of increased mining activity, as it became an important source of iron ore.  Newcrest Mining Ltd. acquired the property in 1991, and porphyry-style copper-gold mineralization in sheeted vein complexes was discovered at the Cadia Hill deposit in 1992 (Holliday et al., 2002; Wilson et al., 2003).  Mineralization at Cadia East and Cadia Far East (currently included in Cadia East) was discovered in 1994 and 1996 respectively.  The high-grade Ridgeway deposit was found in 1996.  Total in-situ resource for the Cadia District has been estimated at 32 Moz Au at 0.7g/t and 4700 kt Cu at 0.36% (Newcrest Mining Ltd., annual report, 2006).  With ore zones extending over 1km across along a 6 km long northwest- striking trend, the Cadia district is the largest porphyry district in Australia. Mineralization is associated with late Ordovician alkalic monzodiorite, monzonite, and quartz-monzonite intrusions of the Cadia Intrusive Complex. Mineralization is typically hosted in stockwork and sheeted vein complexes within the intrusions and the surrounding Forest Reefs Volcanics.  Mineralized porphyries occur typically as dikes and plugs, related to a batholith at depth (Holliday et al., 2002). Intrusions at Ridgeway are dated at ~443 Ma and are monzodioritic to monzonitic in composition (Harris, 2007b; Wilson et al., 2007b).  High-grade ore at Ridgeway occurs in stockworks and is associated with abundant magnetite (Wilson et al., 2003).  Ore in 17  Cadia Hill and Cadia Quarry is concentrated in sheeted veins associated with a composite quartz monzonite stock (Holliday et al., 2002).  Mineralization at Cadia East is primarily hosted in volcaniclastic rocks of the Forest Reefs Volcanics (Holliday et al., 2002; Wilson et al., 2003).  The Big Cadia and Little Cadia skarns occur in a calcareous sandstone unit near the top of the Forest Reefs Volcanics stratigraphy (Forster et al., 2004).  All deposits in the Cadia district display zoned alteration and sulphide distribution characteristic of alkalic porphyry systems (Cooke et al., 2006b; Wilson et al., 2007a). 18  Chapter Two: Stratigraphic Framework  INTRODUCTION  The stratigraphy in the Cadia District preserves a complex history of evolution from a foreland setting to an active volcanic arc complex in the Late Ordovician, to an extensional basin setting in the Silurian.  Structural dismemberment has occurred post- Silurian during numerous overprinting brittle deformation events.  In order to better constrain the effects of this brittle deformation, stratigraphic relationships of both the Ordovician and Silurian is needed to provide a spatial and temporal framework.  To produce structural reconstructions of the district, as discussed in the following chapter, depositional (pre-deformation) lithological distribution and basin geometry must be understood. The uppermost preserved Paleozoic succession in the Cadia district is the Waugoola Group sedimentary cover sequence.  A refined stratigraphy for the Waugoola Group in the Cadia district has helped to constrain the effects of post-mineral deformation in two ways.  First, lithological and rheological differences influenced fold and fault geometry.  Second, distribution of facies, particularly of the basal unit, provides evidence for fault-related topographic controls on deposition of the Waugoola Group. While the focus of this study is the Silurian sedimentary cover succession, a review of older stratigraphic units in the district is necessary to place the Silurian sedimentary cover sequence into context. 19  The stratigraphy of the Cadia district can be subdivided into Ordovician basement and the Silurian cover.  The Ordovician basement is divided further into the Weemalla Formation, the Forest Reefs Volcanics, and intrusive rocks of the Cadia Intrusive Complex (Figure 2.1).  For the sake of simplicity, earliest Silurian strata at the top of the Forest Reefs Volcanics will be grouped with Ordovician basement, as the majority of the Forest Reefs succession is Ordovician in age.  Basement rocks are distinguished from Silurian sedimentary rocks due to differences in alteration.  The Silurian cover rocks are unaltered, whereas Ordovician to early Silurian basement rocks are variably altered by chlorite-hematite and feldspathic alteration (e.g. Holliday et al., 2002; Wilson et al., 2003). Ordovician basement is separated from the Silurian cover by an unconformity. The unconformity between the Ordovician basement, including the Cadia Intrusive Complex and the enclosing Forest Reefs Volcanics, and the Waugoola Group represents unroofing of the intrusions during the early Silurian (Wilson et al., 2007b).  The relative elevation of the unconformity varies across the district, as does the stratigraphic level of the Ordovician basement rocks below.  For this reason, understanding the subjacent Ordovician stratigraphy is critical for understanding the paleogeography and pre-Silurian basinal architecture.      20 R ID G E W A Y B IG  C A D IA C A D IA  Q U A R R Y W H IT E  E N G IN E C A D IA  H IL L L IT T L E  C A D IA C A D IA  E A S T Co pp er  G ul ly Sh ar ps  R id ge Ca dia ng ullo ng C at Gibb k m 0 0 .5 1 2 1 .5 P ro je c ti o n /D a tu m : A u s tr a lia n  M a p  G ri d A G D  6 6 N B a s a lt W a u g o o la G ro u p F o re s t R e e fs V o lc a n ic s W e e m a lla F o rm a ti o n B o u ld er  C o n g lo m er at e Sk ar n C ad ia  In tr u si ve  C o m p le x Fi g u re  2 .1 : Si m p lif ie d  m ap  a n d  s tr at ig ra p h ic  c o lu m n  o f th e C ad ia  D is tr ic t.  C ad ia  H ill  p it  o u tl in e is  s h o w n  w it h  a  d as h ed  li n e.   M aj o r f au lt s ar e la b le d  in  b lu e.   T o p o g ra p h ic  co n to u rs  a re  1 0m . St ra ti g ra p h y m o d ifi ed  fr o m  H ar ri s, 20 07 ; u n p u b lis h ed  re p o rt  to  N ew cr es t M in in g,  L td . G EN ER A LI Z ED  G EO LO G IC  M A P  O F TH E C A D IA  D IS TR IC T 21  ORDOVICIAN BASEMENT  Weemalla Formation  The oldest unit in the Cadia District is the mid to late Ordovician Weemalla Formation (~460-450 Ma) (Packham et al., 1999; Holliday et al., 2002).  It is composed of fine grained, thinly laminated feldspar-rich siltstone and sandstone, and includes minor interbedded carbonate and arenaceous volcaniclastic layers (Holliday et al., 2002).  The depositional environment for the Weemalla Formation was a broad, unconfined deep- water fan of volcanic detritus shed off a partially emergent volcanic edifice (Pogson and Watkins, 1998; Packham et al., 1999). In the western parts of the Cadia district, the Weemalla Formation is at least 2000m thick and hosts part of the Ridgeway deposit (Wilson et al., 2007b).  Here, the Weemalla Formation generally dips gently to the northeast (343/12; strike/dip in AMG, AGD66; Wilson, 2003) and is conformably overlain by the Forest Reefs Volcanics, with a gradational contact (Holliday et al., 2002; Wilson et al., 2003).  The Weemalla Formation has not yet been intersected in drillcore at Cadia East.  Forest Reefs Volcanics  Regionally, the Forest Reefs Volcanics form a major part of the Molong Volcanic Belt and represent the main phase of the late Ordovician-early Silurian Macquarie Arc volcanism in the Cadia district (e.g.Cooke et al., 2007; Wilson et al., 2007a).  The Forest 22  Reefs Volcanics consist of coherent and clastic volcanic and volcaniclastic rocks.  In the Cadia district, the Forest Reefs Volcanics also include minor limestone and calcareous sandstone, and are intruded by hypabyssal intrusives (Holliday et al., 2002; Wilson, 2003; Wilson et al., 2007b).  Wilson (2003) has recognized stratigraphic thickness and  facies variations in the Forest Reefs Volcanics across the Cadiangullong Fault.  To the east of the Cadiangullong fault, the Forest Reefs Volcanics generally dips gently to the southeast (052/12; strike/dip in AMG, AGD66; Wilson, 2003). In the Cadia District, the Forest Reefs Volcanics are up to 2000m thick (Holliday et al., 2002). The Forest Reefs Volcanics was deposited in a shallow submarine basin from extra- and intra- basinal intermediate to mafic volcanism, occurring as a multiple-vent, locally emergent volcanic complex (Squire and McPhie, 2007; Harris, 2007a; Harris 2007b).  Paleofaunal assemblages found in calcareous horizons have yielded a middle Late Orovician age of Forest Reefs Volcanics deposition, roughly from ~460 to ~450 Ma (late Eastonian; Packham et al., 1999), although conodonts and a brachiopod occurrence from the uppermost strata in the Forest Reefs Volcanics suggest an Early Silurian (448 Ma) age (Llandovery-Wenlock; Harris, 2007b.).  This unit hosts gold- and-copper bearing magnetite skarn deposits at Little Cadia and Big Cadia, as well as the Junction Reefs Deposit ~20km south of the Cadia District (Gray et al., 1995; Green, 1999; Packham et al, 1999; Foster et al., 2004).     23  Cadia Intrusive Complex   The Cadia Intrusive Complex intrudes the Weemalla Formation and the Forest Reefs Volcanics, and is unconformably overlain by the Silurian Waugoola Group (Pogson and Watkins, 1998).  Late Ordovician composite intrusions of the Cadia Intrusive Complex range in composition from monzodiorite, diorite, and minor gabbro, to quartz monzonite, and have mineralogic and geochemical shoshonitic affinities (Holliday et al., 2002).  Texture varies from porphyritic to equigranular (Pogson and Watkins, 1998).  Intrusions at Ridgeway are dated ~442 Ma, those at Cadia Hill are dated at ~437 Ma (Wilson et al., 2007b; Harris, 2007b).  SILURIAN COVER  Sedimentary rocks of the Silurian cover succession are temporally correlative on a regional scale with the Waugoola Group, and unconformably overlie the Forest Reefs Volcanics and the Cadia Intrusive Complex (Rickards et al., 2001).  Altogether, the Silurian cover sequence in the Cadia district is less than 200m thick, although true thickness is uncertain due to erosion. Macrofossils recognized in the siltstone include orthid brachiopods and graptolites (e.g. testograptus testis) that constrain the age of the Wuagoola Group in the Cadia District to the Late Wenlock (426-424 Ma) (Figure 2.2; Rickards et al., 2001; Percival, pers. comm.).  Other paleofauna reported in Rickards et al. (2001) have been identified in the Waugoola Group in the Cadia District, and support this age of 24 Figure 2.2:  Macrofossilas collected from the Cadia HIll Acess Road and trace fossils from the Waugoola Group sedimentary cover sequence.  A:  brachiopod (orthid).  B:  graptolite (testograptus testis).  C:  brachiopod (a. australis).  D:  brachiopod (orthid).  E and F:  flute casts in siltstone collected from Cadia East.  G:  ripple casts in sandstone collected from Sharps Ridge.   H:  ripples in sandstone collected from Cadia East (same location as flute casts). A B C D E F G H 25  deposition.  Ripples and flute casts are also preserved in the siltstone and sandstone across the district. In the Cadia District, the Waugoola Group is divided into a basal unit, a lower siltstone-dominant succession, and an upper sandstone-dominant succession (Figure 2.3). The sandstone-dominant upper unit is divided into interbedded siltstone and sandstone, of varying proportions (siltstone- or sandstone- dominant) and overlying massive sandstone. The basal unit varies across the district (Figure 2.4).  Locally boulder conglomerate, calcirudite limestone, or redbeds occur at the unconformity.  Basal Units   Different packages at the base of the Silurian sedimentary cover sequence in the Cadia district reflect different depositional environments at the onset of Waugoola Group sedimentation.  Changes in the basal unit across the district provide insight into post- mineral uplift and erosion, and the resultant paleogeography.   Interpreting these facies variations is therefore critical to understanding the basin geometry that controlled Waugoola Group deposition and reconstructing both pre- and post- depositional deformation.      26 +v v v v v v v v ar ko se b la ck  s ilt st o n e ca lc ir u d it e co n g lo m er at e re d b ed s sa n d st o n e si lt st o n e b as al  u n it SU RF A C E D IS TR IB U TI O N  O F TH E W A U G O O LA  G RO U P C A D IA  D IS TR IC T C A D IA  H IL L C A D IA  Q U A RR Y C A D IA  E A ST Sh ar p s Ri dg e C op p er  G ul ly C atGibb Cad ian gu llon g Po w er lin e N 0 0 .5 1 km Fi g u re  2 .3 : G en er al iz ed  W au g o o la  G ro u p  s tr at ig ra p h y an d  s u rf ac e d is tr ib u ti o n  (m ap ).  B as al  u n it  v ar ie s ac ro ss  th e d is tr ic t, an d  re d b ed s, lim es to n e,  a n d  c o n g lo m er at e d o  n o t ty p ic al ly  a p p ea r t o g et h er . Re la ti ve  t h ic kn es se s sh o w n  o n  t h e st ra ti g ra p h ic  c o lu m n  a re  b as ed  o n  av er ag e va lu es  fo r C ad ia  E as t.  F R V  =  F o re st  R ee fs  Vo lc an ic s, W M  =  W ee m al la  F o rm at io n . C ad ia  H ill  p it  o u tl in e sh o w n  a s a b la ck  d as h ed  li n e. in te rb ed d ed  si lt st o n e an d  sa n d st o n e sk ar n FR V W M 27 U n d iff er en ti at ed  W au g o o la  G ro u p Li m es to n e an d  C al ci ru d it e Re d b ed s B o u ld er  C o n g lo m er at e LE G EN D C A D IA  H IL L C A D IA  E A ST Sh ar p s R id ge Co pp er  G ul ly Cad iang ullo ng Gibb C at Po w er lin e N 1 0 km Fi g u re  2 .4 : M ap  s h o w in g  b as al  d is tr ib u ti o n  o f d iff er en t b as al  u n it s fo r t h e Si lu ri an  W au g o o la  G ro u p  in cl u d in g  s u rf ac e an d  s u b su rf ac e o cc u rr en ce s co n st ra in ed  b y d ri llc o re  d at a.   A re as  w h er e th e W au g o o la  G ro u p  is  u n d iff er en ti at ed  re fle ct  u n ce rt ai n ty  in  in te rp re ti n g  d ri llc o re  d at a o r s p ar se  c ov er ea g e.  G en er al  d is tr ic t g eo lo g y an d  fa u lt s ar e in cl u d ed  fo r r ef er en ce . 28  LIMESTONE  The basal unit for much of the Waugoola Group at Cadia East is a pink, red, white, grey or green biolithic, variably recrystallized limestone and fossiliferous calc- rudite (Figure 2.5).  Rounded limestone and biolithic coral clasts vary in size between the centimeter to the meter scale.  Rare clasts of Forest Reefs Volcanics are also present. Infill varies between gritty micaceous arkose, red, green, or grey siltstone, and calcareous sand or mud.  Some areas of the basal limestone unit are recrystallized and stylolitized, and appear massive and grey in drillcore.  A conformable, gradational contact with overlying siltstone and/or arkose is common.  The base of the limestone at the unconformity with the Forest Reefs Volcanics or the Cadia Intrusive Complex may be brecciated, with altered volcanic-derived clasts and unaltered siltstone clasts set in calcite-rich sedimentary matrix. The basal limestone varies in thickness across the district, but is typically ~10m. At Cadia Quarry, it is up to 50m thick, and to the north, it locally exceeds vertical thicknesses of 100m; this may in part represent structural thickening, rather than depositional control.  Only one surface outcrop of the basal limestone unit is present in Cadia East (686,432 E, 6,295,830 N).  The basal limestone is absent from pit wall exposures at Cadia Hill, to the west of the Gibb fault and on Sharps Ridge.  It thins and is absent from the section along the Cat fault in Cadia East, as well as other un-named faults recognized in the sedimentary cover sequence (see chapter 3).   29 Figure 2.5:  Limestone and Calcirudite from the base of the Waugoola Group at Cadia East.  A:  clastic limestone outcrop in Copper Gully Creek.  B:  massive limestone from CE046.  C:  grey recrystallized clastic limestone with some stylolites.  D:  fine-grained clastic calcirudite.  E:  rounded pebble conglomerate with carbonate matrix near the base of the limestone.  F: carbonate matrix conglomeratic limestone.  G:  coarse grained calcirudite. A B C D E F G 30  BOULDER CONGLOMERATE  Where the basal limestone is absent in the footwall of major basement faults, the basal unit of the Waugoola Group is a matrix-supported, polymict conglomerate (Figure 2.6).  Pebble to boulder sized clasts include altered volcanic rock, intrusive rock, and massive magnetite-pyrite skarn, as well as minor local unaltered siltstone, arkose, and limestone.  Unaltered sandstone clasts are uncommon.  Most clasts are subangular and poorly sorted set in a grey, green or red siltstone and/or feldspathic fine-grained sandstone. Clasts at the base of the boulder conglomerate appear locally derived from the Forest Reefs Volcanics or Cadia Intrusive Complex. By contrast, unaltered clasts of other Waugoola Group rocks appear toward the top of the boulder conglomerate.  Thickness of the basal conglomerate varies between ~20-120m, with the thickest sections adjacent to faults.  Where observed, a conformable graditional contact exists between the boulder conglomerate and overlying siltstone packages.  RED SILTSTONE  In the Cadia Hill open pit, a ~20m thick package of red siltstone is present.  This unit is not laterally extensive, and is mostly restricted to a ~0.15 km2 area near the intersection of the Copper Gully and Gibb faults (Figure 2.7).  Isolated outliers of red siltstone also occur in Cadia East.  Where this unit does not occur directly on the unconformity, it conformably overlies the boulder conglomerate.  Red siltstones are massive to laminated with interbedded conglomeratic zones (with clasts of locally 31 B C D E F Figure 2.6:  Boulder conglomerate at the base of the Waugoola Group.  A:  basal conglomerate in local lows along the unconformity from the southern wall of Cadia Hill pit.  B:  close-up of conglomerate from A.  C: boulder conglomerate from the haul road near the southern wall of Cadia Hill pit with locally derived angular clasts of the Forest Reefs Volcanics.  D: boulder conglomerate in Copper Gully Creek with locally derived skarn clasts.  E:  boulder conglomerate from Copper Gully Creek with clasts of Waugoola Group limestone, arkose, and siltstone.  F:  conglomer- ate from drillcore with hematite-rich matrix and locally derived volcanic clasts. sandstone conglomerate volcaniclastic A 32 A B C D E F Figure 2.7:  Photographs of hematite-rich siltstone redbeds.   A:  massive to laminated red siltstone from the southern wall of Cadia Hill pit.  B:  massive to laminated red siltstone with thin arkosic horizon. C:  angular boulders of locally derived Forest Reefs Volcanics in red siltstone from the southern wall of the Cadia Hill pit.   D:  pebbles of Forest Reefs Volcanics in red siltstone and arkosic matrix.  E and F: pebbles of hematite-poor siltstone in arkosic redbeds. 33  derived Forest Reefs Volcanics or unaltered Waugoola Group siltstone) and rarer arkosic beds.  The upper contact with green or gray siltstone is poorly preserved, but appears gradational.  The distinctive red color is more likely a result of deposition in oxidizing subaerial conditions rather than a product of hematitic hydrothermal alteration as this reddened appearance is spatially restricted to the more massive siltstones that are relatively impermeable.  This unit is therefore a locally developed, intra-basinal redbed sequence.  It is uncertain whether this unit is time correlative with the basal limestone seen elsewhere in the Cadia district.  Lower Siltstone-Dominant Succession  The basal unit is conformably overlain by laminated to massive grey, green, or brown siltstone with rare fossiliferous, bioturbated, and calcareous horizons (Figure 2.8). Millimeter-scale ripple marks and rare trace fossils occur.  Total thickness of siltstone package varies between ~50 and 200m (averaging 70m), and generally thickens towards the east.  The siltstone package is locally absent (e.g., Sharps Ridge), inferred to be related to areas of higher elevation.  Despite this, this siltstone package is laterally extensive and the most volumetrically significant unit in the Waugoola Group sedimentary cover. Medium-to coarse-grained sandstone interbeds (0.1 to 0.3m, up to 3m thick) are abundant in the siltstone (Figure 2.9).  Degree of consolidation varies between moderately well-indurated and poorly indurated gritty textures.  Color varies between white, green, and tan.  The mineralogy of these beds is dominantly feldspathic, with 34 A B C D E F G H Figure 2.8:  Photographs of Waugoola Group siltstone from drillcore.  A:  laminated siltstone with faint wispy flaser bedding.  B:  irregular flaser bedding in siltstone.  C:  clast supported breccia in flaser bedded siltstone with rotated angular clasts; flaser bedding is disrupted and chaotic.   D:  siltstone matrix supported breccia with angular clasts of flaser bedded siltstone.  E:  carbonate veins in massive black shale.  F:  dense carbonate veins in flaser bedded siltstone with minor angular siltstone clast breccia.  G:  fossilliferous zone in massive black shale marginal to arkose horizon.  H:  fossiliferous zone in massive muddy siltstone . 35 A B DC E F G H Figure 2.9: Coarse grained arkosic horizons in the silstone package. A: thick arkose horizon with mica and carbonate. B: thin horizon of gritty micaceous arkose with bedding parallel fabric. C: irregular contact between arkose and enclosing siltstone. D: irregular contact between arkose and fossiliferous black shale. E: angular siltstone clasts incorporated at the margin of arkosic horizon. F: arkose matrix supported siltstone clast breccia. G: arkose clasts in siltstone pebble conglomerate. H: arkose clasts and matrix in siltstone pebble conglomerate. 36  minor lithic clasts and quartz.  Many of these coarse arkosic beds contain abundant mica, with some being more carbonate rich.  Irregular and wispy contacts with the enclosing siltstone are also present, indicative of soft-sediment deformation. Rip-ups of angular siltstone clasts also occur. Flaser bedding, defined by fine wisps of carbonaceous mud, is common in the grey and green siltstone, and may display regular or extremely chaotic bedding orientations.  Where flaser bedding is most disrupted, clast supported breccias of siltstone are present.  Angular clasts of flaser bedded siltstone are also present in the boulder conglomerate and locally developed conglomeratic zones in the siltstone package.  Flaser bedding is associated with deposition in a distal fan environment, where changes in current are frequent. Black shale associated with calcareous and fossiliferous material is also present locally in the lower siltstone-dominant succession.  This unit does not appear to be laterally extensive and does not exceed 20m in bed thickness.  Local conglomeratic interbeds contain sub-rounded, pebble sized clasts of siltstone and arkose in a siltstone matrix.  Upper Sandstone-Dominant Succession  At Cadia, interbedded and graded sandstone and siltstone (the upper sandstone- dominated succession) conformably overlies the siltstone-dominant lower portion of the Waugoola Group (Figure 2.10).  The proportion of siltstone to sandstone varies continuously between siltstone-dominated (up to 90 % siltstone) and sandstone- 37 A B C D E F Figure 2.10:  Sandstone-dominant upper stratigraphic units of the Waugoola Group in the Cadia District, including interbedded siltstone and sandstone and massive to thick-bedded quartz sandstone. A:  siltstone-dominant turbidites from the high wall in Cadia Hill pit (Sharps Ridge).  B:  interbedded siltstone and sandstone of roughly equal proportions, from the southern wall of the Cadia Hill pit.  C: drillcore from sandstone-dominant turbidite with bedding-parallel fabric in the siltstone bed; graded bedding is evident.  D:  graded bedding in sandstone-dominated turbidite.  E:   thick bedded to massive quartz sandstone from the southern wall of Cadia Hill pit.  F:  massive sandstone from drillcore. 38  dominated (up to 90% sandstone) horizons.  Relative proportions of siltstone- and sandstone-dominated units vary over the district, as does stratigraphic position relative to each other.  Thickness of individual graded beds commonly varies on the centimeter scale, although some beds may exceed 2 meters in the interbedded siltstone and sandstones.  Total thickness of the upper sandstone-dominant succession is up to 40m. The uppermost outcropping unit in the Waugoola Group consists of fine- to medium-grained massive to thick-bedded (1-4m) buff-colored or grey quartz sandstone. Thickness varies between 10 and 40m, but commonly occurs as 20m beds of massive to thick-bedded sandstone.  True thickness of this unit is unknown due to erosion.  INTERPRETATIONS   Paleogeography and Basin Evolution  After magmatism ceased in the earliest Silurian, erosional unroofing of the mineralized intrusions of the Cadia Intrusive Complex and the altered enclosing Forrest Reefs Volcanics strata took place.  Volcanic, intrusive, and skarn clasts in the basal conglomerate and at the base of the calc-rudite provide evidence of uplift and erosion of Ordovician basement rocks prior to deposition of Waugoola siltstones and sandstones. Some of the eroded material was deposited locally in areas of relatively low elevation as boulder conglomerate. The boulder conglomerate at the base of the sedimentary cover sequence appears spatially related to major faults that penetrate the Ordovician basement.  Thick debris 39  flows such as these are present on either side of Sharps Ridge, between the Powerline fault and the Copper Gully fault, and also in the footwall of the Gibb fault (Figure 2.11). The boulder conglomerate contains locally sourced clasts and was deposited in a high energy environment, which reflects local topography prior to and during earliest Waugoola Group deposition.  Because the conglomerate is localized along faults, it was probably deposited in local lows associated with fault scarps, such as half-graben basins that formed during rifting. Clasts of Waugoola Group rocks in upper portions of the boulder conglomerate fault scarp deposits indicate syn-depositional faulting was important in maintaining topography.  Redbeds were deposited in a localized area at the intersection of the Gibb fault with the Copper Gully fault, and are exposed on the southern wall of Cadia Hill pit (Figure 2.12). Redbeds provide evidence that part of the district underwent subaerial sedimentation during the early stages of rifting and associated Waugoola Group deposition in the Cadia District.  As subsidence continued, ephemeral lakes in which redbeds were deposited dropped below sea level, and deposition of oxidized sediments gave way to deposition of fine-grained marine sedimentary rocks.  However, it is uncertain if submarine deposition of other basal units, i.e. the limestone, was taking place elsewhere in the district at this time, or if continued subsidence following redbed deposition produced the depocenter for carbonate sediments.  Continued subsidence led to deposition of carbonate sediments in relative basinal lows.  Clasts of limestone in the boulder conglomerate provide evidence for the persistence of significant local topography and continued conglomerate deposition during carbonate sedimentation.  Concomitant with conglomerate deposition, carbonate detritus, 40 ++ + + + + + + + + N C 46 4 N C 20 5 C E0 73 C E0 69 C E0 55 C E0 09 N C 36 3 C E1 14 C E1 09 C E1 06 C E0 79 + C ad ia  E as t Sh ar ps  R id ge H oa re s C re ek C ad ia  H ill Gibb C at Co pp er  G ul ly Po w er lin e H IG H LO W H IG H Ca t Co pp er Gu lly Pow erlin e Gibb Pow erlin e Gibb Co pp er G ully Ca t H IG H H IG H LO W Bar onn ess Fisht ail B lac k B et ty Bl ac k Be tt y Fishta il Ba ron ne ss + + PC 40 2 PC 40 4 Fi g u re  2 .1 1 : In te rp re ti ve  s ec ti o n s sh o w in g  s tr at ig ra p h ic  v ar ia ti o n s in  t h e W au g o o la  G ro u p  a cr o ss  S h ar p s Ri d g e an d  C ad ia  E as t.  B lu e "h ig h " an d  " lo w " in d ic at e re la ti ve  s tr at ig ra p h ic  p o si ti o n  o f t h e Fo re st  R ee fs  V o lc an ic s p re se rv ed  a t th e u n co n fo rm it y.   A : c ro ss  s ec ti o n  c o n st ra in ed  b y d ri llc o re  a n d  s u rf ac e m ap p in g  sh o w s va ri at io n s in  t h e b as al  u n it . R ef er en ce  m ap  b el o w  s h o w s se ct io n  li n e in  y el lo w  a n d  d ri llc o re  c o lla r l o ca ti o n s in  re d ; s ee  a p p en d ix  3 . B : i n te rp re ta ti o n  o f Sh ar p s Ri d g e d ep o si ti o n al  e n vi ro n m en t d u ri n g  W au g o o la  G ro u p  d ep o si ti o n . V ar ia ti o n s in  b as al  li th o lo g y re fle ct  lo ca l f au lt -r el at ed  t o p o g ra p h y.   D as h ed  li n es  re p re se n t p re se n t- d ay  fa u lt  c o n fig u ra ti o n , a n d  a re  p ro vi d ed  fo r r ef er en ce . Th es e fa u lt s w er e n o t n ec es sa ri ly  a ct iv e at  t h is  s ta g e.  H o ar es  C re ek Sh ar p s R id g e C ad ia  E as t N S H o ar es  C re ek Sh ar p s R id g e C ad ia  E as t N S A B sa nd st on e si lts to ne b as em en t re d b ed s co n g lo m er at e lim es to n e LE G EN D N0 .5  k m PC 40 0 + 0 .5  k m N C 46 4 N C 20 5 C E0 73 C E0 69 C E0 55 C E0 09 N C 36 3 C E1 09 C E1 06 C E0 79 PC 40 0 PC 40 4 PC 40 2 41 Fo ys Ca di an gu llo ng SS W B c Si Si  T u rbSs  T u rb Ss Ss  T u rbS s Ss  T u rb Si  T u rb Si B c R d R d A B 0 .1  k m LE G EN D b ed di ng fa ul ts sa nd st on e sa nd st on e- do m in an t t ur b id ite si lts to ne -d om in an t t ur b id ite si lts to ne un di ff er en tia te d b as em en t Fi g u re  2 .1 2 : O b se rv ed  g eo lo g y an d  in te rp re te d  d ep o si ti o n al  e nv ir o n m en t fr o m  t h e so u th er n  w al l o f C ad ia  H ill  p it . A : P an o ra m ic  p h o to g ra p h  o f t h e W au g o o la  G ro u p  s ed im en ta ry  c ov er  s eq u en ce  w it h  s tr at ig ra p h y su p er im p o se d . B : I n te rp re ti ve  re co n st ru ct io n  o f u n d ef o rm ed  s eq u en ce . Lo ca lly  d er iv ed  a n g u la r c la st s w er e sh ed  o ff  o f f au lt  s ca rp s in to  lo ca l h al f- g ra b en  b as in s. Re d b ed s w er e d ep o si te d  in  e p h em er al  la ke s lo ca liz ed  b y fa u lt s.  A s su b si d en ce  c o n ti n u ed , s ed im en ts  fi lle d  in  to p o g ra p h y an d  e ve n tu al ly  c ov er ed  lo ca l h ig h s. Su b se q u en t sh o rt en in g  t ilt ed  a n d  fa u lt ed  t h e en ti re  p ac ka g e. 42  including fragments of corals, began shedding into developing basins.  Laterally continuous limestone horizons at the base of the Waugoola Group imply a dominantly submarine depositional setting (Figure 2.13).  The absence of limestone north of the Copper Gully fault on Sharps Ridge and west of the Gibb Fault may suggest that these areas were relative topographic highs and Cadia East was an area of relatively low relief. Additionally, thinning of limestone approaching the Cat fault and other faults in Cadia East may reflect that these faults controlled basin geometry.  The basal limestone in the Cadia District probably does not represent in-situ reefs, but transported carbonate material derived from reefs that formed on regionally significant palaeo-highs.  The fragmental nature, lateral continuity and fairly constant thickness of basal limestone supports this interpretation. The siltstone package was deposited in a low energy marine environment.  Local highs in the Cadia District persisted during this stage, as evidenced by the lack of significant siltstone on Sharps Ridge.  The geometry and mineralogy of arkose horizons suggests intermittent sediment input from an intermediate igneous source.  Future palaeocurrent studies, detrital zircon dating, and thorough mineralogical analysis may clarify the provenance of these horizons. As rates of sedimentation overtook rates of subsidence, filling of basins reduced local topography and a fine-grained marine succession was deposited.  The interbedded siltstone and sandstone unit is interpreted as a turbidite package, which is commonly deposited at slope-breaks as a result of mass wasting.  Thick- to- massive sandstone beds that compose the uppermost unit suggest abundant sediment supply and fast sedimentation rates.  As active extension associated with rifting ceased, isostatic sagging 43 LO W H IG H H IG H CAD IAN GU LLO NG FOY S GIB B H IG H LO W CAD IANG ULL ONG FOY S GIB B E W C ad ia  E as t C ad ia  H ill E W C ad ia  E as t C ad ia  H ill sa nd st on e si lts to ne b as em en t re d b ed s co n g lo m er at e lim es to n e Fi g u re  2 .1 3 : C ro ss -s ec ti o n  a n d  p al eo g eo g ra p h ic  in te rp re ta ti o n  fo r C ad ia  H ill  a n d  C ad ia  E as t.  B lu e "h ig h " an d  " lo w " in d ic at es  t h e re la ti ve  s tr at ig ra p h ic  le ve l o f t h e Fo re st  R ee fs  V o lc an ic s p re se rv ed  a t th e u n co n fo rm it y.   A : S tr at ig ra p h ic  c ro ss  s ec ti o n  co n st ra in ed  b y d ri llc o re  a n d  s u rf ac e m ap p in g . D ri llc o re  c o lla rs  ar e sh o w n  o n  re fe re n ce  m ap  b el o w ; s ee  a p p en d ix  3 . L im es to n e is  p re se n t ea st  o f t h e G ib b  fa u lt , a n d  t h e si lt st o n e an d  sa n d st o n e p ac ka g es  a re  t h ic k.  W es t o f t h e G ib b  fa u lt , t h e lim es to n e is  a b se n t, th e si lt st o n e an d  s an d st o n e p ac ka g e is  t h in , an d  t h e b as al  u n it  is  b o u ld er  c o n g lo m er at e an d  re d  s ilt st o n e.   B : In te rp re ta ti o n  o f d ep o si ti o n al  e n vi ro n m en t b as ed  o n  s ec ti o n  A . D as h ed  li n es  re p re se n t p re se n t- d ay  fa u lt  p o si ti o n s fo r r ef er en ce ; fa u lt s in  t h is  c o n fig u ra ti o n  a re  n o t n ec es sa ri ly  p re se n t at  t h is  st ag e.   F au lt  s ca rp  d ep o si ts  a n d  s u b ae ri al  s ed im en ta ti o n  in  ep h em er al  la ke s w es t o f t h e G ib b  F au lt . C o n ti n u ed  s u b si d en ce  d ro p s th e la ke s b el o w  s ea  le ve l. Li m es to n e is  d ep o si te d  in  a  su b m ar in e b as in  t o  t h e ea st  o f t h e G ib b  F au lt , a n d  c o n ti n u ed  b as in -f ill in g  re su lt s in  a  t h ic k si lt st o n e an d  s an d st o n e p ac ka g e. Fa u lt  S ca rp  D ep o si ts (c o n g lo m er at e) Su b m ar in e D ep o si ti o n (b as al  li m es to n e) Su b ae ri al  Se d im en ta ti o n (r ed b ed s) Th in , C o ar se r s ed im en ts  o n  lo ca l h ig h s N C 48 2 C E1 50 C E1 08 C E0 75 C E1 39 C E1 00 N C 19 5 C E0 03 C E0 70 N 0 .5  k m AA B N0 .5  k C ad ia  E as t Sh ar ps  R id ge H oa re s C re ek C ad ia  H ill Gibb C at Co pp er  G ul ly Po w er lin e Cad ian gul lon g + + + + + + + + + N C 48 2 C E1 50 C E1 08 C E0 75 N C 19 5 C E1 39 C E1 00 C E0 70 C E0 03 44  of the rift basin resulted in widespread deposition of marine sedimentary rocks across the regional rift basin.  At this stage, local topographic controls on sedimentary facies may have persisted, but were probably less important, as small, isolated basins were overwhelmed by finer-grained marine sedimentation. The evolution of basins in the Cadia district as recorded in the Waugoola Group, preserves a transition from deposition of clastic and carbonate rift sediments to a fine- grained marine succession during the early late Silurian.  Equivalent successions are regionally extensive across central New South Wales (being Siluro-Devonian in age). Where preserved, such successions are globally recognized as a rift-sag sequence (Figure 2.14).  Rift-sag sequences are deposited when extension and subsidence driven by tectonic processes give way to the effects of thermal relaxation of the lithosphere following rifting (e.g. Blake and Stewart, 1992; O’Dea et al., 1997).  When this occurs, isolated basins separated by topographic highs are filled in, and are overlain by regionally extensive transgressive marine successions (e.g. Betts and Lister, 2001).  In the Cadia district, clastic sedimentation into locally developed, fault related basins is preserved in variations in the spatial distribution of basal units and represents the rift phase of the rift- sag sequence.  As subsidence continues entering the sag phase, these isolated basins are overwhelmed by marine sedimentation, represented in the Cadia district by the siltstone and sandstone packages.     45 A : O n se t o f R if ti n g B : C o n ti n u ed  S u b si d en ce C : Is o st at ic  S ag g in g RIFT SAG Fi g u re  2 .1 4 : G en er al iz ed  te ct o n ic  m o d el  fo r r ift -s ag  s eq u en ce  d ep o si ti o n . A  ri ft  s ag  s eq u en ce  o cc u rs  w h en  is o la te d  h al f- g ra b en  b as in s fo rm  a t th e o n se t o f ri ft in g  a n d  a re  fi lle d  w it h  lo ca lly  d er iv ed  c la st ic  m at er ia l ( A ).  If  ri ft in g  a n d  b as in  s u b si d en ce  c o n ti n u es , t h e b as in  g ro w s o u tw ar d  a n d  c o n ti n u es  to  fi ll,  b u t th e th ic kn es s o f s ed im en ta ry  ro ck s b ei n g  d ep o si te d  a t th is  t im e is  s ti ll in flu en ce d  b y h al f- g ra b en  g eo m et ry  (B ).  O n ce  a ct iv e ex te n si o n  a ss o ci at ed  w it h  ri ft in g  c ea se s,  th e ex te n d ed  c ru st  b eg in s to  c o o l, an d  a s it  is  lo ad ed  w it h  s ed im en ts , i t b eg in s to  is o st at ic al ly  s ag  (C ).  A s th e ra te  o f s ed im en t su p p ly  o ve rw h el m s th e ra te  o f ex te n si o n , l o ca l t o p o g ra p h ic  b ar ri er s ar e re m ov ed  a s b as in s fil l w it h  fi n er  g ra in ed  m ar in e se d im en ts .  T h is  p ro ce ss  is  re fle ct ed  re g io n al ly  a n d  in  t h e C ad ia  D is tr ic t b y th e W au g o o la  G ro u p . M o d ifi ed  fr o m  O ls en , 1 99 7 an d  S ch lis ch e et  a l.,  2 00 0.  C O O LI N G 46  Regional Correlations  In general, the Waugoola Group is regionally interpreted as a transgressive marine sequence, beginning with shallow water carbonates and evolving to deeper water conditions (Jenkins, 1978; Pogson and Watkins, 1998).  Lithic sandstone and conglomerate at the base of the Waugoola Group grade upward into the Cobblers Creek Limestone (Jenkins, 1978; Pogson and Watkins, 1998).  The Cobblers Creek Limestone consists of coarse feldspathic and conglomeratic sandstone and cobble to boulder conglomerate with a gradational upper contact into thinly bedded calcirudite (containing rounded pebbles of corals in a calcareous matrix) and calcarenite containing fragments of corals, limestone clasts and rare volcanic detritus (Jenkins, 1978; Pogson and Watkins, 1998).  This study lithologically correlates the Cobblers Creek Limestone with the basal limestone at Cadia East, in agreement with fossil ages reported in Rickards et al. (2001). Regionally, carbonates of the Cobblers Creek Limestone are conformably overlain by siliceous siltstones and shales of the Glendalough Formation, which also contains minor coarse calcareous quartzo-feldspathic sandstones (Burly Jacky Sandstone Member), black shales and dolomitic limestones (Ashleigh Member), and locally developed redbeds (Chaucer Red Bed Member) (Jenkins, 1978; Bischoff, 1986).  Based on the refined stratigraphy presented in this study, the siltstone package in the Cadia district probably correlates regionally with the Glendalough Formation. The Burly Jacky Sandstone Member recognized regionally consists of coarse grained calcareous quartzofeldspathic sandstones and varies in thickness from ~10 m to ~45 m (Jenkins, 1978; Pogson and Watkins, 1998).  It locally contains volcanic clasts of 47  the Angullong formation and transported corals, as well as fossiliferous sandstone and limestone with brachiopods and corals (Jenkins, 1978; Pogson and Watkins, 1998). Micaceous arkose horizons in the siltstone package described in this study appear to have similar lithological characteristics to the Burly Jacky Sandstone Member of the Glendalough Formation. In other regional localities where the Waugoola Group is preserved, the Ashleigh Member overlies the Burly Jacky Member and consists of black shale containing abundant graptolites locally interfingered with silty dolomitic limestone and varies in thickness from 20-30m (Jenkins, 1978; Pogson and Watkins, 1998).  Black shale and associated locally fossiliferous zones within the lower siltstone-dominant portions of the sedimentary cover sequence identified in drillcore from the Cadia district may correlate regionally with the Ashleigh Member of the Glendalough Formation. The Chaucer Redbed Member is regionally described as massive to laminated red siltstone and red siltstone matrix conglomerate containing locally derived clasts (Jenkins, 1978).  The redbeds are locally developed and thin relative to the enclosing Glendalough Formation siltstone package. In the Cadia District, locally developed redbeds and pebble conglomerates with red siltstone infill described in this study may be broadly correlative with the Chaucer Redbed Member.  However, the Chaucer Redbed Member occurs relatively high in the regional Glendalough Formation stratigraphy, whereas in Cadia, it appears near the base of the Waugoola Group.  This suggests that the redbeds and associated conglomerate at the base of the sedimentary cover rocks in the Cadia District may represent an older package 48  Interbedded siltstone and sandstone occurring above the siltstone-dominant lower portion of the stratigraphy were likely due to deposition from turbidite flows, and are unlike any part of the Waugoola Group stratigraphy described by Jenkins (1978).  The relatively coarser grain size and irregular, interbedded nature of this unit suggest deposition in a proximal submarine fan environment.  Of particular interest is the source of quartz-rich detritus that makes up the fine- to medium-grained sandstones at the uppermost portion of the stratigraphy.  No quartz-rich rocks are locally present, so this material must have been sourced regionally and transported. The correlation of the sedimentary cover sequence in the Cadia district regionally with the Waugoola Group indicates that rift-basin formation and sedimentation was widespread in the Late Silurian (regionally, known to extend into the Devonian).  Basins filled with Waugoola Group sedimentary rocks were probably much more laterally extensive than their present-day configuration as isolated belts suggests. Similarities between the sedimentary cover sequence in the Cadia district and more regional Waugoola Group are significant for two reasons:  firstly, that early Waugoola Group sedimentation was controlled by local basin geometries that developed across the collapsing Macquarie Arc.  Second, sedimentary detritus may have been in part sourced regionally and transported rather than derived entirely from local sources. This may explain the provenance of carbonates in the basal limestone as well as the micaceous arkose and the quartz-rich sedimentary rocks in the higher portions of the Waugoola Group stratigraphy in the Cadia District.  This supports the rift-sag sequence interpretation for the Cadia district, and the cover rocks across the Macquarie Arc (coincide with development of the Molong High) on a regional scale. 49  IMPLICATIONS   Changes in sedimentary processes and lithology in the Cadia District reflect the eastern migration of the active centre of Macquarie Arc magmatism during the Late Ordovician, and the transition to an extensional tectonic setting in the Silurian (Figure 2.15).  These major cycles of deposition, punctuated by periods of uplift and erosion (notably during the Early Silurian and the Devonian) correspond to regional tectonic events and orogenesis. Following mineralization, intrusions of the Cadia Intrusive Complex and the Forest Reefs Volcanics were uplifted and eroded to various levels across the Cadia district.  This phase of uplift is preserved as a depositional hiatus between the Ordovician basement rocks and the Waugoola Group sedimentary cover sequence.  Variable uplift and erosion is recorded by differences in the relative stratigraphic position of the Forest Reefs Volcanics subjacent to the unconformity. Calcareous sandstone horizons in the upper portion of the Forest Reefs Volcanics host skarn deposits, and can be used as a marker horizon in district reconstructions (Harris, 2007a).  Where the skarn-bearing horizon is preserved, as in Cadia East and Central Cadia, relatively high units in the FRV stratigraphy are subjacent to the Waugoola Group sedimentary cover sequence (Figure 2.16).  In the footwall of Cadiangullong Fault, exposed in the south wall of the Cadia Hill open pit, and on Sharps Ridge, to the east, the skarn-bearing horizon was removed prior to Waugoola Group deposition, with relatively low stratigraphic units of the FRV at the unconformity. 50 Tectonic Synthesis E-W SHORTENING ~380-370 Ma TABBERABBERAN ~430-380 Ma RIFTING AND BASIN FORMATION WAUGOOLA GROUP DEPOSTION E-W SHORTENING EASTWARD ARC MIGRATION, INTRUSION EMPLACEMENT ~440-430 Ma BENAMBRAN OROGENY ~490-440 Ma MACQUARIE ARC MAGMATISM MVB Cowra Trough Molong High Hill End Trough Capertee High Cu-Au-Mo Au MVB JNVB RGVB sea level MVB JNVB RGVBDelamerian Margin sea level Figure 2.15:  Regional tectonic controls on changing depositional environment in the Cadia District. JNVB=Junee-Narromine Volcanic Belt, MVB=Molong Volcanic Belt, RGVB=Rockley-Gulgong Volcanic Belt. The Weemalla Formation was deposited in the forearc as the volcanic center of the Macquarie Arc migrated eastward.  The Forest Reefs Volcanics were deposited during formation of the Molong Volcanic Belt.  The Ordovician basement rocks of the Cadia district were subsequently shortened during the Benambran Orogeny.  A phase of rifting followed the Benambran Orogeny, and rift basins were filled with sedimentary packages such as the Waugoola Group.  Early in rifting, local basin geometry controlled deposition.  Thermal relaxation of the lithosphere resulted in basinal sagging, and local topographic barriers were overcome as basin filling progressed, and widespread transgressive marine sequences were deposited.  This is known as a rift-sag sequence.  During the Devonian, Tabberabberan Orogeny, the Waugoola Group was faulted and folded, as discussed in Chapter Three.  Timing and regional vergence from Glen et al., 2007. Late Silurian - Devonian rift basin sedimentary rocks incl. the Waugoola Group Late Silurian stitiching plutons Early Silurian marine sedimentary rocks Late Ordovician-Early Silurian porphyries Late Ordovician-Early Silurian Macquarie Arc volcanic rocks Cambrian-Ordovician oceanic crust and marine sedimentary rocks Precambrian-Cambrian craton and accreted continental rocks 51 LOWER LOWER UPPER UPPER Figure 2.15:  Map showing the stratgrapihc position of the Forest Reefs Volcanics at the unconformity with the overlying Silurian Waugoola Group.  This reflects variable uplift and erosion of the Ordovician basement prior to deposition of the sedimentary cover sequence. N 0 0.5 1 km Legend F o re s t R e e f V o lc a n ic s W a u g o o la G ro u p Faults Cainozoic Basalt Polymict siltstone-matrix conglomerate Cadia Intrusive Complex Volcaniclastic rocks, lava and rare limestone Magnetic skarn Weemalla Formation: Siltstone and turbidites Cadia Hill Pit Undifferentiated sandstone and siltstone 52  Differences in the erosional level of the FRV suggest significant uplift and generation of topography in the early Silurian. The Waugoola Group represents the drowning and dismemberment of the Macquarie Arc during rifting in the late Silurian.  Variations in the basal unit across the district suggest that early in Waugoola Group deposition, local basin geometry was fault controlled, and significant topography influenced lithological distribution.  This topography persisted into the later stages of Waugoola Group deposition, as evidenced by the absence of siltstone on Sharps Ridge.  On Sharps Ridge relatively low levels of the Ordovician volcanic stratigraphy are preserved below the Silurian unconformity and only the upper portion of the Waugoola Group are preserved. The Forest Reefs Volcanics at the unconformity in the hanging wall of the Gibb fault are also at a relatively low stratigraphic level.  In the hanging wall of the Gibb fault, redbeds and boulder conglomerate at the base of the stratigraphy signify subaerial deposition in local fault-bounded basins.  This facies relationship suggests that topographic highs formed during uplift and exhumation of the Cadia Intrusive Complex in the earliest Silurian persisted into the late Silurian.  Finer-grained marine sedimentation followed initial rifting and clastic sedimentation was replaced by prograding wedges of regionally derived material as local basins were overwhelmed during continued subsidence related to basinal sagging. Variable uplift of the Forest Reefs Volcanics following the Benambran Orogeny resulted in preservation of different stratigraphic levels at the unconformity across the district.  It also produced long-lived topography that appears to be fault related. Furthermore observed variations in the basal unit of the Waugoola Group reflect 53  deposition into locally developed, fault controlled basins.  Therefore, faults must have been present prior to Waugoola Group deposition in the Cadia District.  Shortening during the Devonian Tabberabberan Orogeny inverted the basin bounding faults and disrupted the Waugoola Group stratigraphy in the Cadia District. 54  Chapter Three:  Structural Relationships in the Cadia District  INTRODUCTION  In order to better guide future exploration and development activities in the Cadia district it is important to recognize the extent and magnitude of post-mineralization deformation.  Major reverse faults of the Cadiangullong Fault system dismember the orebody at Cadia Hill and juxtapose different levels of the intrusive complex across the district.  Furthermore, each deposit is preserved in a different fault block and a distinctive structural domain (Harris, 2007a).  Understanding the role of post-mineral deformation is therefore critical to recognizing the dismemberment of mineralized zones and thereby refining the ore deposit model for the Cadia District. The late Silurian Waugoola Group sedimentary cover sequence at Cadia is the key to understanding the structural effects of post-mineral deformation on the orebody. Magmatism associated with mineralization ceased during the earliest Silurian at the end of the Benambran Orogeny.  Subsequent uplift and erosion removed approximately 2km of material, and brought the orebodies to the surface.  Deposition of the Waugoola Group cover sequence in extensional basins during the Silurian was followed by regional shortening, which locally produced complex fold-and-thrust geometries.  Due to the relative timing of Waugoola Group deposition, faults and folds preserved therein record only post-mineral deformation.  The goal of this project is to document the deformation of the cover sequence in order to reconstruct the Cadia District, and to better understand 55  the role of post-Benambran deformation on the current distribution of ore-bearing lithologies.  REGIONAL AND DISTRICT-SCALE STRUCTURE  Regional Structure  The dominant regional structural fabric in the Cadia District and surrounding areas is exemplified by north trending reverse faults and related splays, such as the Wyangalla-Werribee Fault System (Figure 3.1).  These reverse faults are moderately west-dipping, curviplanar, and may have a strike slip component (Glen, 1998; Pogson and Watkins, 1998).  The Werribee Fault extends into the Cadia District, where it is locally mapped as the Cadiangullong Fault system, and superposes Ordovician volcanic rocks and turbiditic sandstone and siltstone on the west against Silurian sedimentary rocks to the east (Pogson and Watkins, 1998).  Overall, the Werribee-Cadiangullong fault extends for 30 km to the south (Wilson, 2003). A second set of regionally important faults are NW-striking, and are typically cross-cut by and more weakly developed than the N-striking set, which suggests an older age of formation (Wilson, 2003). These structures are similarly oriented with the WNW- striking Lachlan Transverse Zone, a deep crustal lineament which is inferred to have localized mineralizing intrusions on a regional scale (Glen and Walshe, 1999; Finlayson et al., 2002; Wilson, 2003). The Cadia District occurs at the regional intersection of the 56 Figure 3.1:  Regional map, modified from Bathurst 1:250,000 map by Pogon and Watkins, 1998.  Faults shown in blue. 57 VV V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V VV V V VV V V V V V V V VV V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V V VV V V V V VV Blayney Orange Carcoar Mount Canobolas Cadia Fault W errib ee Fault G odolphin UTM Zone 55, AGD 1966 1:250,000 km 0 5 10 Cabonne Group Silurian Intrusions Adaminaby Group Undifferentiated Devonian Units Kenilworth Group Undifferentiated Cainozoic Cover Ordovician Intrusions, including Cadia Intrusive Complex Cudal Group Weemalla Formation Forest Reefs Volcanics Mumbil Group Ashburnia Group Waugoola Group Undifferentiated Silurian Units Carboniferous intrusions SI LU RI A N O RD O V IC IA N v v v v LEGEND N 58  north-northeast striking reverse faults and the west-northwest striking Lachlan Transverse Zone.  District-Scale Structural Trends  Structures in the Cadia District can be generally subdivided into three major sets based on orientation:  (1) N-striking, W-dipping reverse faults and associated folds and fault splays, (2) NE- striking, NW-dipping faults and associated folds that are locally developed at the district scale, and (3) WNW striking, steeply N-dipping oblique- reverse faults (Figure 3.2, Table 3.1, Figure 3.3).  Newcrest Mining Ltd. has recognized these faults in the Ordovician basement rocks based on drillcore intersections, but until this study, the interaction of these faults with the sedimentary cover rocks was incompletely understood.  N-striking faults include the Cadiangullong Fault System (part of the regional Wyangala-Werribee Fault System), and the Gibb fault, which bound the Cadia Hill deposit (Figure 3.4).  NE-striking faults in the Cadia District include the Copper Gully Fault System, the Cat Fault, and the Powerline Fault (Figure 3.2).  Across the district, N- and NE- striking faults generally steepen to the W and NW respectively.  The Little Cadia Fault and the PC40 Fault belong to the WNW striking group, and are related to skarn mineralization near Cadia East and Ridgeway, respectively.  The Pyrite Faults at Cadia East are also west-striking (and do not outcrop).  None of the W-striking faults are expressed in the Silurian Waugoola Group sedimentary cover sequence, although N- and NE- striking faults disrupt both basement and cover rocks.  59 Figure 3.2:  Generalized geology map of the Cadia District.  Geology of the Waugoola Group shown in shades of pink and purple.  Faults shown in blue.  Basement units mapped by Newcrest Mining, Ltd.  Section line (A-A') for figure 3.3 shown in yellow. 60 +R ID G EW A Y C A D IA  Q U A R R Y C A D IA  H IL L C A D IA  E A ST Sh ar p s R id g e Cad ian gul lon g Gibb C at Co pp er  G ul ly B IG  C A D IA LI T TL E C A D IA Po w er lin e Foy s Fi sh ta il Ba ro nn es s PC -4 0 Li tt le  C ad ia No rth Pu rp le Py ri te ? War reng ong Le ge nd Forest Reef Volcanics Waugoola Group Fa u lt s C ai n oz o ic  B as al t M as si ve  to  t h ic k b ed d ed   q u ar tz  sa n d st o n e In te rb ed d ed  s ilt st o n e an d  s an d st o n e M as si ve  to  la m in at ed  si lt st o n e an d  co ar se -g ra in ed  m ic ac eo u s ar ko se Po ly m ic t si lt st o n e- m at ri x co n g lo m er at e C ad ia In tr u si ve  C o m p le x D ac it e D yk es Vo lc an ic la st ic  ro ck s, la va  a n d  ra re  li m es to n e M ag n et ic  s ka rn W ee m al la  F o rm at io n : Si lt st o n e an d  tu rb id it es C ad ia  H ill  P it N Pr o je ct io n /D at u m : A u st ra lia n  M ap  G ri d ; A G D 66 0 0 .5 1 k m +684,960mE 6, 29 4, 72 0m N +687,960mE 6, 29 4, 72 0m N A A ' 61 Powerline Fault Cadiangollung Fault Gibb Fault Cat Fault Copper Gully Fault NE N N NE NE 300m 300m 600m 200m 20m steep -> N steep -> W steep -> N moderate -> W moderate -> N N of Sharps Ridge W of Cadia Hill E of Cadia Hill Cadia East S of Sharps Ridge FAULT STRIKE DIP MIN. VERT. DISP. LOCATION Table 3.1:  Orientation and displacement on major basement thrusts in the Cadia District.  Minimum vertical displacement is estimated from offset of the unconformity.  Orientation and displacement documented by Newcrest Mining Ltd. and in Harris, 2007a. 62 C A D IA  H IL L C A D IA  Q U A R R Y R ID G EW A Y C A D IA  E A ST Gib b Pyri te Cad iang ullo ng Pow erli ne Purp le A A ' W ee m al la  F o rm at io n ~ 46 0- 45 0 M a Fo re st  R ee fs  V o lc an ic s ~ 45 0- 43 5 M a D es tr u ct iv e ~ 46 0- 45 0 M a C o n st ru ct iv e Le ge nd Fa u lts B ed d in g W au g o o la  G ro u p ~ 42 6- 42 4 M a CIC R id g ew ay ~ 44 2 M a C ad ia  H ill ~ 43 7 M a 0 0 .5 1 km Ve rt ic al  =  H o ri zo n ta l Sc al e C ai n oz o ic  B as al t M ag n et ic  S ka rn FRV Fi g u re  3 .3 : Lo n g  N W -S E se ct io n  a cr o ss  t h e C ad ia  D is tr ic t.  S ec ti o n  li n e sh o w n  in  y el lo w  o n  F ig u re  3 .2 . Sk ar n - b ea ri n g  a n d  b ed d ed  u n it s in  t h e Fo re st  R ee fs  V o lc an ic s (F R V ) r ep re se n t th e u p p er , d es tr u ct iv e fa ci es  o f t h e st ra ti g ra p h y.   L o w er  p o rt io n s o f t h e Fo re st  R ee fs  V o lc an ic s ar e m o re  m as si ve , a n d  re p re se n t th e co n st ru ct iv e fa ci es . Th e C ad ia  In tr u si ve  C o m p le x (C IC ) h as  b ee n  s ep ar at ed  in to  2  p h as es  a t R id g ew ay  a n d  C ad ia  H ill  b as ed  o n  d iff er en t ag es  o f e m p la ce m en t (W ils o n  e t al ., 20 07 b ).  A g es  t h at  a p p ea r in  t h e le g en d  a re  fr o m  P ac kh am  e t al ., 19 99 ; R ic ka rd s et  a l.,  2 00 2;  H o lli d ay  e t al ., 20 02 ; W ils o n  e t al ., 20 07 , a n d  H ar ri s, 20 07 . Fi g u re  a ft er  H ar ri s, 20 07 . 63 C ad ia n g u llo n g Fi sh ta il Co pp er  G ul ly G ib b Foy sC at Bar on ess Blac k Be tty SE 0 .5 k m Sh ar p s R id g e C A D IA  E A ST C A D IA  H IL L So u th er n  W al l Ea st er n  W al l Fi g u re  3 .4 : A n n o ta te d  a er ia l p h o to g ra p h  o f C ad ia  H ill  o p en  p it  lo o ki n g  s o u th ea st  to w ar d  S h ar p s R id g e an d  C ad ia  E as t.  M aj o r r ev er se  fa u lt s m ap p ed  in  t h e O rd ov ic ia n  b as em en t b y N ew cr es t M in in g  L td . a re  s h o w n  in  y el lo w . So u th er n  a n d  ea st er n  w al ls  o f C ad ia  H ill  p it  (f ig u re s 3. 8 an d  3 .1 0,  re sp ec ti ve ly ) a re  m ar ke d  fo r r ef er en ce . 64  N- STRIKING FAULTS  The Cadiangullong Fault is a system of anastomosing, curviplanar, moderate-to- steeply west-dipping reverse faults with an estimated minimum vertical offset of 300m, based on offset of the unconformity at the base of the Waugoola Group sedimentary cover (Figure 3.3).  It superposes rocks of the Late Ordovician Cadia Intrusive Complex to the west against the Silurian sedimentary cover sequence to the east.  It is exposed in the northwest wall of the Cadia Hill pit, where it appears as a 1m-10m wide zone of black cataclasite gouge and intensely fractured wallrocks.  In the Cadia District, the Cadiangullong Fault extends from the south, where it connects with the regional Werribee Fault.  To the north, it curves around the Cadia Hill deposit and merges with the NE-striking Powerline fault.  Whether the Cadiangullong Fault system continues to the north is uncertain, due to thick Mesozoic cover.  Splays off the Cadiangullong Fault include the Foys fault and the Baronness-Fishtail faults. The Foys fault is a SE-striking, steeply W-dipping thrust splay off the Cadiangullong fault system.  In the South wall of the Cadia Hill pit, the fault is a 20m wide zone of intensely fractured siltstone-dominant Waugoola Group sedimentary rock. Silurian siltstone occurs in the footwall of the Foys fault at depths up to 300m.  In the Waugoola Group cover, the Foys fault superposes siltstone from the lower portion of the stratigraphy over interbedded siltstones and sandstones of the upper sandstone-dominant portion of the stratigraphy. The Fishtail/Baroness faults are NE-striking splays off the Cadiangullong system. In the northeast corner of the Cadia Hill open pit, the faults are steeply dipping and fold the massive sandstone of the Waugoola Group.  These faults link 65  the Cadiangullong fault system with the Powerline fault, and are also filled with black cataclasite gouge. The Gibb Fault is another N- striking, moderate-to-steeply west-dipping reverse fault with west-over-east vertical displacement of ~300m (Figure 3.3).  It occurs to the east of the Cadia Hill open pit, and has been intersected in the Cadia East Decline, where it superposes high-level destructive facies of the Forest Reefs Volcanics over the Silurian Waugoola Group.  In the Silurian Waugoola cover, the Gibb Fault is manifest as a 0.5m- 2m wide zone of milled rock-matrix breccia and clay gouge.  Folds parallel to the fault are present in the surrounding area.  NE- STRIKING FAULTS  The Powerline fault lies north of and is roughly parallel to Sharps Ridge.  It consists of a complex system of northwest-dipping faults, and appears to be a splay off the N-striking Gibb Fault.  Faults of the Powerline system separate the Cadia Hill deposit from the Cadia Quarry deposit.  Slivers of intrusive, volcanic, and sedimentary cover rocks are bounded by the faults.  The displacement on individual faults is unknown, but overall offset of internal intrusive contacts suggests a net vertical displacement of ~600m across major NE-striking faults in Central Cadia (Figure 3.3; Harris, 2007a). The Copper Gully fault is exposed in the southeast corner of the Cadia Hill Pit.  It is planar and narrow, and has a reddish clay gouge.  The Copper Gully fault bounds Sharps Ridge on the south.  Powerline and Copper Gully faults appear to have been important during post-mineral uplift and erosion of the Cadia Intrusive Suite and the 66  enclosing Forest Reefs Volcanics, and also to have been important in controlling distribution of Waugoola Group sedimentary facies during late Silurian deposition (see chapter 2). The Cat Fault is a major NE-striking fault in Cadia East.  This study has also identified a significant parallel structure to the Cat fault ~500m to the north in the Waugoola Cover.  Juxtaposition of sedimentary lithologies, changes in bedding contours, and folding in the sedimentary cover sequence at the surface are attributed to proximity to these faults.  STRUCTURES IN THE SILURIAN WUAGOOLA GROUP  Shortening in the late Ordovician-early Silurian basement rocks of the Cadia District was accommodated along a few moderate-to-steeply dipping major faults, including those of the N-striking Cadiangullong and Gibb fault systems, and the NE- striking Powerline, Copper Gully, and Cat faults (Figure 3.5).  These faults were identified by Newcrest Mining Ltd. using drillcore.  Basement fault blocks are mostly composed of massive volcaniclastic and intrusive rocks, which preserve little evidence for deformation (i.e. folds) outside of discrete fault zones.  Therefore, basement fault blocks probably behaved as relatively rigid blocks during shortening.  This is consistent with the behavior of fault blocks in thick-skinned thrust belts (e.g. Chambers et al., 2004; Molinaro et al., 2005; Grey et al., 2006; Mouthereau and Lacombe, 2006; and references therein).  In the sedimentary cover rocks of the Waugoola Group, shortening was accommodated by a variety of structures, including faults, folds, and low-angle slip along 67 +CADIA HILL CADIA QUARRY CADIA EAST Shar ps Ri dge Copp er Gu lly Cat G ib b Cadiangullong Powerline N 0 0.5 1 km Legend Faults Cadia Hill Pit Basalt Sandstone Interbedded sandstone and siltstone Siltstone Conglomerate Cadia Intrusive Complex Forest Reefs Volcanics Magnetic skarn Weemalla  Formation 1 2 3 1 2 3 POLES TO BEDDING equal area Figure 3.5:  Domain analysis of bedding measurements from the Silurian Waugoola Group in the Cadia District.  Domain 1 consists of Cadia Hill, in the footwall of the Cadiangullong fault, and the hanging wall of the Gibb fault.  Domain 2 is Sharps Ridge, in the footwall of the Gibb fault, but the hanging wall of Copper Gully Fault.  Domain 3 is Cadia East, in the footwall of the Gibb fault and the Copper Gully fault.  Differences in bedding orientation across domains provide evidence for fault block rotation and basement fault control on orientation in the cover rocks. 68  bedding planes and the unconformity with the underlying Ordovician basement rocks. This style of deformation is characteristic of thin-skinned thrusting (Chambers et al., 2004; Molinaro et al., 2005; Mouthereau and Lacombe, 2006).  The differences in deformation style reflect rheological contrasts between relatively strong basement rocks and the weaker bedded cover rocks. In order to constrain the effects of post-mineral deformation on the ore-bearing lithologies, the interaction between structures in the sedimentary cover rocks of the Silurian Waugoola Group and major faults in the basement were examined in detail.  The strike of thrust faults and related folds in the sedimentary cover sequence is similar to that of underlying basement faults identified in during exploration and resource drilling by Newcrest Mining Ltd.  Qualitatively, the intensity of deformation recorded in the Waugoola Group sedimentary cover rocks increases approaching major basement faults. Therefore, basement faults control the orientation and distribution of faults and folds in the cover rocks (Figure 3.6).  Slip along basement faults is manifested in the Waugoola Group sedimentary cover sequence as a combination of through-going faults and intra- cover faults and folds. The scale and character of intra-cover faults differ from basement structures that have broken through the cover sequence.  In general, through-going faults that link directly with basement faults are steeper and produce wider zones of deformation in the cover sequence.  Where major basement faults cut up into the overlying cover rocks, the resultant structures in the sedimentary cover occur up-dip of, and trend parallel, to the faults below.  Where these faults disrupt the Waugoola Group stratigraphy, sedimentary bedding steepens and is intensely fractured.  Intra-cover faults are at a low angle or 69 Le ge nd Forest Reef Volcanics Waugoola Group Fa u lt s 10 m  c o n to u rs C ai n oz o ic  B as al t U n d iff er en ti at ed  s ilt st o n e an d  s an d st o n e Po ly m ic t si lt st o n e- m at ri x co n g lo m er at e C ad ia In tr u si ve  C o m p le x D ac it e D yk es Vo lc an ic la st ic  ro ck s, la va  a n d  ra re  li m es to n e M ag n et ic  s ka rn W ee m al la  F o rm at io n : Si lt st o n e an d  t u rb id it es C ad ia  H ill  P it Fi g u re  3 .6 : M ap  s h o w in g  s tr u ct u ra l m ea su re m en ts  m ap p ed  in  t h e W au g o o la  G ro u p  s ed im en ta ry  c ov er  se q u en ce  in  t h e C ad ia  D is tr ic t.  N o te  th at  p yr it e fa u lt s, sh o w n  w it h  a  re d  d as h ed  li n e,  d o  n o t ap p ea r i n  t h e co ve r ro ck s. 40 25 90 15 25 30 10 35 20 30 30 15 35 60 50 30 60 15 30 30 25 30 25 40 30 4 0 254 5 60 15 35 40 30 40 30 50 45 45 20 50                                       C A D IA  Q U A R R Y C A D IA  H IL L C A D IA  E A ST Sh ar p s R id g e Cad ian gul lon g Gibb C at Co pp er  G ul ly LI T TL E C A D IA Po w er lin e Foy s Fi sh ta il Ba ro nn es s N Pr o je ct io n /D at u m : A u st ra lia n  M ap  G ri d ; A G D 66 0 0 .5 1 k m p yr it e fa u lt s? + +684,960mE 6 ,2 94 ,7 20 m N 6, 29 4, 72 0m N 687,960mE 70  parallel to bedding and may be very narrow, with little to no fault gouge.  These faults are connected to basement structures via a complex network of interconnected faults and folds (Figure 3.7, Figure 3.8). The geometry produced by interaction between basement and cover structures results in steep basement faults appearing to become flatter at the unconformity.  This relationship is visible on the southern wall of Cadia Hill pit, where the Foys fault brings Ordovician basement rocks over Silurian cover (Figure 3.7, Figure 3.8).  The southern wall of Cadia Hill pit represents a fault-bounded block that occurs in the footwall of the Foys fault and the hanging wall of the Gibb Fault.  In the basement rocks, the Foys fault and the Gibb fault both dip ~75o to the west.  In the sedimentary rocks, the Foys fault is a steeply dipping zone (>80o to the west) of intensely fractured rock and sheared gouge where it continues through the cover rocks as an up-dip extension of the basement fault. Shortening accommodated along the Foys fault in the basement is also distributed in the cover sequence among multiple detachments, including the unconformity and bedding planes.  These detachments cut through the cover rocks at a low angle to bedding and produce intra-cover faults and folds in the overlying sedimentary rocks (Figure 3.8). The average dip of the unconformity and the overlying sedimentary cover rocks on the southern wall of Cadia Hill pit is ~30o to the west.  This is consistent with Waugoola Group bedding measurements from Cadia East (Figure 3.5).  It is geometrically reasonable that the unconformity and the bedding of the sedimentary cover rocks was tilted due to rotation of basement blocks during reverse faulting, as is characteristic of thick-skinned thrust belts (e.g. Chambers et al., 2004; Molinaro et al., 2005; Grey et al., 2006; Mouthereau and Lacombe, 2006; and references therein).  This 71 +CADIA QUARRY CADIA HILL CADIA EAST Shar ps Ri dge Cadiangullong Fault G ib b Fa ul t Cat F ault Cop per Gull y Fa ult LITTLE CADIA Powerline  Fault Foys Fault Fisht ail Ba ro nn es s 10 8 11 12 14a 17 17a-c 18b 18a 16 13 Figure 3.7:  Reference map for locations of photographic figures in chapter 3. Photographic subject is shown with a yellow dot or a line. Numbers correspond with figure numbers, and are positioned where the photograph was taken to illustrate the direction of point-of-view. Heavy yellow lines represent panoramic photographs. Figure 8 is a panorama of the southern wall of Cadia Hill pit, taken from location 8 looking south, as shown by thin yellow lines. Figure 10 is a panorama of the eastern wall of Cadia Hill pit taken from location 10 looking southeast., shown by thin yellow lines. Figures 13 and 16 are panoramic photographs of roadcuts on the Cadia Hill access road. Figure 16 is taken looking south, and figure 13 is taken looking north. Figures 14 a-c were taken underground, in the Cadia East Decline, and are each ~20m apart. 9 14b 15 d N 0.5km boulder conglomerate Ordovician volcanics magnetic skarn Weemalla Formation Basalt Cover Cadia Intrusive Complex siltstone sandstone interbedded siltstone and sandstone 72 Fo ys Ca di an gu llo ng SS W B c Si Si  T u rbS s Tu rb Ss Ss  T u rb Ss Ss  T u rb Si  T u rb Si B c R d R d b ed d in g fa u lt s sa n d st o n e sa n d st o n e- d o m in an t tu rb id it e si lt st o n e- d o m in an t tu rb id it e si lt st o n e re d b ed s co n g lo m er at e u n d iff er en ti at ed  b as em en t 0. 1 km Si lu ri an  C o ve r LE G EN D Fo ys  F au lt  (b as em en t) C ad ia n g u llo n g  F au lt  (b as em en t) b ed d in g fa u lt s eq u al  a re a Fi g u re  3 .8 : R el at io n sh ip s b et w ee n  b as em en t fa u lt s an d  fa u lt s in  t h e W au g o o la  G ro u p  s ed im en ta ry  c ov er  s eq u en ce  o n  t h e so u th er n  w al l o f C ad ia  H ill  p it . L o ca ti o n o f p an o ra m a sh o w n  o n  fi g u re  3 .7 . A : p an o ra m ic  p h o to g ra p h  o f t h e W au g o o la  G ro u p  w it h  s tr at ig ra p h y ov er la in . F au lt s ar e sh o w n  in  b lu e.  B ed d in g  is  t ra ce d  in  y el lo w . B c= b o u ld er  c o n g lo m er ar e;  R d = re d b ed s;  S i= si lt st o n e;  S i T u rb =  s ilt st o n e d o m in an t tu rb id it e;  S sT u rb =  s an d st o n e- d o m in an t tu rb id it e;  S s= sa n d st o n e.  F oy s Fa u lt  fl at te n s at  t h e u n co n fo rm it y an d  s h o rt en in g  in  t h e co ve r s eq u en ce  is  p ar ti ti o n ed  a m o n g  m an y fa u lt s at  a  lo w  a n g le  to  b ed d in g. , i n cl u d in g  a lo n g  t h e u n co n fo rm it y.  T h es e d et ac h m en ts  a re  s h o w n  in  b lu e.   F oy s fa u lt  is  a  fo o tw al l s p la y o ff  t h e C ad ia n g u llo n g  F au lt . St er eo n et s ar e p ro vi d ed  to  s h o w  t h e sp at ia l r el at io n sh ip  b et w ee n  b ed d in g  a n d  fa u lt s in  t h e co ve r r o ck s an d  u n d er ly in g  b as em en t fa u lt s.  T h is  re la ti o n sh ip  s u g g es ts  t h at  t ilt in g  o f W au g o o la  G ro u p  b ed d in g  d o w n  to  t h e w es t w as  t h e re su lt  o f t h ru st -b lo ck  ro ta ti o n . A 73  would have brought the Silurian unconformity and bedding planes into a favorable orientation to accommodate shallow-level thrusting (Figure 3.9). Along the southern wall of Cadia Hill pit, the unconformity between altered Ordovician volcanic rocks and unaltered Silurian sedimentary rocks outcrops for ~100m along a single bench.  Locally, the irregular unconformity surface has acted as a detachment; slip along the unconformity has produced clay gouge and small-scale faults and folds in the Waugoola Group sedimentary rocks above (Figure 3.9). Where local lows in the unconformity surface occur, the detachment climbs section into the sedimentary rocks and follows bedding planes.  In this way, shortening on the Foys fault is accommodated in the cover sequence along minor planes of weakness at a low angle to Waugoola Group bedding that flatten at the interface between basement and cover. The eastern wall of Cadia Hill pit essentially provides an in situ cross-section of Sharps Ridge (Figure 3.7, Figure 3.10). The position of the unconformity is topographically high relative to elsewhere in the district, and approximately 35m of Waugoola Group is preserved.  Farther to the east along Sharps Ridge, the unconformity is at least 100m beneath the cover.  During Waugoola Group deposition in the Late Silurian, Sharps Ridge was a relative topographic high in the basin (see chapter 2). During subsequent shortening and basin inversion, reverse movement on faults to either side of Sharps Ridge produced a complex fold-and-thrust geometry in the surrounding cover rocks. On the eastern wall of Cadia Hill pit, bedding in the Waugoola Group sedimentary cover sequence is deflected at a minor basement fault (Figure 3.7, Figure 3.11).  The fault is steeply dipping and strikes at a high angle to bedding of the cover 74 g o u g e Fo re st  R ee fs  V o lc an ic s sa n d st o n e SS E 1 m 1 m Fi g u re  3 .9 : Ph o to g ra p h s o f u n co n fo rm it y fe at u re s o n  t h e so u th er n  w al l o f C ad ia  H ill  P it . Lo ca ti o n s ar e sh o w n  o n  F ig u re  3 .7. . A : d u p le x in  t h e sa n d st o n e im m ed i- at el y ab ov e a lo ca l h ig h  o n  t h e u n co n fo rm it y.   A  s liv er  o f s ilt st o n e is  a ls o  p re se n t. Th e u n co n fo rm it y is  lo ca lly  c ov er ed  b y a th ic k zo n e o f g o u g e.   B : sl ip  a lo n g  lo ca l h ig h s o n  t h e u n co n fo rm it y su rf ac e p ro d u ce s g o u g e.   D et ac h m en ts  b re ak  u p -s ec ti o n  a n d  s lip  is  p ar ti ti o n ed  in to  s ilt st o n e h o ri zo n s. A B si lt st o n e sa n d st o n e g o u g e Fo re st  R ee fs  V o lc an ic s SS E 75 Bla ck B ett y Ca pl io ES E Copper Gully Fis hta il Grab en Ba ro nn es s Sh ar p s R id g e C o p p er  G u lly  C re ek Si Ss Ss Ss  T u rb Si  T u rb Fi g u re  3 .1 0 : P an o ra m ic  p h o to g ra p h  o f t h e ea st er n  w al l o f C ad ia  H ill  p it  h ig h lig h ti n g  t h e st ra ti g ra p h y o f th e W au g o o la  G ro u p  s ed im en ta ry  c ov er  s eq u en ce  a cr o ss  Sh ar p s R id g e an d  im p o rt an t b as em en t fa u lt s. Lo ca ti o n  o f t h is  p h o to g ra p h  is  s h o w n  o n  F ig u re  3 .7 . B ed d in g  is  s h o w n  in  y el lo w . F au lt s ar e sh o w n  in  b lu e.  R el at iv el y fla t- ly in g  b ed s o f s an d st o n e (S s)  a n d  in te rb ed d ed  s an d st o n e an d  s ilt st o n e (S s tu rb , S i t u rb ) h av e ex p er ie n ce d  re la ti ve ly  lo w  le ve ls  o f d ef o rm at io n , e xc ep t ad ja ce n t to  fa u lt s. Th ic k- b ed d ed  to  m as si ve  s an d st o n e o n  t h e n o rt h er n  s lo p e o f S h ar p s R id g e ar e fo ld ed  a g ai n st  t h e Fi sh ta il an d  B ar o n es s fa u lt s. Si lt st o n e (S i) o n  t h e so u th er n  s id e o f S h ar p s R id g e d ip s st ee p ly  to  t h e so u th , f o llo w in g  t h e u n co n fo rm it y,  a n d  is  m o re  in te n se ly  fa u lt ed  a n d  fo ld ed . S h ar p s R id g e is  a  p o p p ed  u p  b lo ck , an d  w as  re la ti ve ly  h ig h  in  e le va ti o n  d u ri n g  W au g o o la  G ro u p  d ep o si ti o n . S u b se q u en t sh o rt en in g  re ac ti va te d  re ve rs e fa u lt s o n  e it h er  s id e an d  re su lt ed  in  c o m p le x d ef o rm at io n  o f t h e co ve r s eq u en ce  a ro u n d  t h e m ar g in s o f t h e b as em en t p o p -u p . b as em en t fa u lt s co ve r ro ck s b ed d in g fa u lt s B ar o n n es s Fi sh ta il G ra b en B la ck  B et ty Sh ar p s R id g e Sp at ia l D at a LE G EN D b ed di ng fa ul ts sa nd st on e sa nd st on e- do m in an t t ur b id ite si lts to ne -d om in an t t ur b id ite si lts to ne un di ff er en tia te d b as em en t 0. 25  k m 76 EN E 5 m 5 m 5 m A B C Fi g u re  3 .1 1 : P h o to g ra p h s o f t h e ea st er n  w al l o f C ad ia  H ill  p it . L o ca ti o n s sh o w n  o n  F ig u re  3 .7 . U n co n fo rm it y sh o w n  in  g re en . B ed d in g  in  t h e W au g o o la  G ro u p sh o w n  in  y el lo w . A : p an o ra m ic  p h o to g ra p h  s h o w in g  re la ti ve ly  fl at -l yi n g  b ed d in g  in  t h e se d im en ta ry  c ov er  s eq u en ce  n ea r t h e to p  o f S h ar p s R id g e d is ru p te d  lo ca lly b y fa u lt s (B ) a n d  lo ca l i rr eg u la ri ti es  o n  t h e u n co n fo rm it y (C ). Th ic k zo n es  o f g o u g e al o n g  t h e u n co n fo rm it y o n  t h e so u th er n  w al l o f t h e C ad ia  H ill  p it  a re  a b se n t h er e.  B : A  s p la y o ff  t h e G ra b en  F au lt , w h ic h  o u tc ro p s 50 m  to  t h e n o rt h . T h ic k- b ed d ed  s an d st o n e o n  t h e le ft  is  ju xt ap o se d  a g ai n st  in te rb ed d ed  s ilt st o n e an d sa n d st o n e o n  t h e ri g h t ac ro ss  a  s te ep ly  d ip p in g  fa u lt  a t a h ig h  a n g le  to  b ed d in g.  C : F au lt s an d  fo ld s in  s ed im en ta ry  ro ck s d ra p ed  in  lo ca l b as em en t lo w s. th es e fe at u re s re fle ct  re la ti ve ly  s m al l a m o u n ts  o f d ef o rm at io n  c o m p ar ed  to  u n co n fo rm it y fe at u re s o n  t h e so u th er n  w al l o f C ad ia  H ill  p it . 77  rocks.  Thick-bedded, to massive sandstones occupy the hanging wall of the fault, whereas interbedded siltstone and sandstone are in the footwall.  Steeply dipping beds of massive sandstone are folded against the fault (Figure 3.11b).  This fault is similar in orientation to the nearby Graben fault, which outcrops 50m to the north in the hanging wall, and is associated with open folds and steep bedding in massive sandstone.  It is plausible that this fault is a splay off Graben fault, and accommodated shortening in the Sharps Ridge pop-up fault block. Away from faults bedding in the Waugoola Group on Sharps Ridge is relatively flat-lying, and the sedimentary cover sequence appears less deformed than on the southern wall of the Cadia Hill open pit, where bedding is tilted down to the west ~ 30o. Slip along the unconformity on top of Sharps Ridge is probably less significant than along the southern wall, except where this surface is intersected by major faults, such as the Fishtail/Baroness fault complex.  Some deformation of the cover rocks is associated with local irregularities on the unconformity (Figure 3.11c).  Rather than the rounded peaks and troughs observed on the south wall, the unconformity at the top of Sharps Ridge appears to have a scalloped edge with sedimentary rocks draped in the lows (Figure 3.11c). On the sides of Sharps Ridge, faults are more numerous and the Waugoola Group rocks are more deformed.  For example, on the southern side of Sharps Ridge, Waugoola Group bedding dips moderately to the south, where it is parallel with the unconformity (Figure 3.12a).  Cover rocks are folded and faulted against the unconformity.  Small fault slivers of siltstone are preserved in the hanging wall of the Black Betty fault, which outcrops ~50m to the south (Figure 3.12b).  These features suggest that the Silurian 78 N E 1 m A B Fo re st  R ee fs  Vo lc an ic s 0 9 0 /6 0 0 9 0 /5 5 0 9 0 /7 5 Fi g u re  3 .1 2 : F au lt s an d  fo ld s in  s ilt st o n e o n  t h e so u th er n  s lo p e o f S h ar p s R id g e.  L o ca ti o n  is  s h o w n  o n  fi g u re  3 .7 . A : s te ep ly  d ip p in g  b ed d in g in  t h e W au g o o la  G ro u p  s ed im en ta ry  ro ck s ag ai n st  t h e u n co n fo rm it y.  M ea su re m en ts  a re  g iv en  in  s tr ik e/ d ip  fo rm at , w it h  d ip  a lw ay s to  t h e ri g h t, an d  a re  in  t h e p ro je ct io n  A u st ra lia n  M ap  G ri d ; d at u m  A G D 66 . B : f au lt  s liv er  o f i n te n se ly  fr ac tu re d  s ilt st o n e sh o w in g  d ef o rm ed  n at u re o f W au g o o la  G ro u p  s ed im en ta ry  ro ck s b et w ee n  B la ck  B et ty  F au lt , w h ic h  o u tc ro p s ~ 50 m  to  t h e so u th , a n d  t h e u n co n fo rm it y. 79  sedimentary cover rocks on the Sharps Ridge pop-up fault block experienced the most intense deformation along the margins. Where basement faults are exposed, as in the examples described above, deformation in the cover sequence can be related directly to reactivation of the controlling basement faults.  These relationships can be used to make inferences about basement faults where only the cover rocks are present.  For example, in Cadia East, the Cat fault is expressed in the overlying cover sequence as a steep fault that outcrops on the Cadia Hill access road (Figure 3.7, Figure 3.13).  Interbedded siltstone and sandstone in the hanging wall is folded, with fold hinges sub-parallel to the fault plane.  Minor thrusts in the hanging wall with ramp-flat geometry are also present (Figure 3.13).  Siltstone in the footwall is relatively undeformed.  Minor intra-cover faults and folds relate directly to the Cat fault, which can be identified in the cover rocks by the steep dip, the high angle of the fault plane to Waugoola Group bedding, and juxtaposition of interbedded sandstone and siltstone against massive siltstone. Folds in the cover rocks can also be used to identify basement faults.  This is because folds are typically spatially restricted to the cover rocks where underlying faults in the basement are present, and are related to controlling faults (Figure 3.13).  Open folds in Waugoola Group cover rocks commonly overlie basement thrusts where they fail to break through the cover sequence.  In Copper Gully, an open fold in thick bedded- to massive sandstones has a shallowly SW-plunging axis that is parallel to the Copper Gully fault in the basement (Figure 3.7, Figure 3.14a).  An open fold with a similar geometry is present near Little Cadia (Figure 3.14b), implying that a basement fault lies below.  80 Nm 0 5 si lt st o n e sa n d to n e- d o m in an t si lt st o n e- d o m in an t Ca t F au lt A 2 1 0 /4 0 1 6 5 /4 0 1 9 5 /3 0 2 8 5 /2 5 2 2 0 /2 5 2 2 5 /1 5 2 3 0 /1 5 1 3 5 /3 5 2 2 5 /2 0 2 3 5 /1 5 2 5 5 /1 5 2 1 0 /1 5 2 4 0 /1 5 2 1 0 /2 0 2 4 0 /3 0 2 5 0 /8 5 2 5 /4 5 6 5 /9 0 2 5 0 /9 0 5 /5 5 1 9 5 /2 5 8 5 /8 5 9 5 /9 0 3 5 5 /5 5 2 6 0 /8 5 7 0 /9 0 2 5 0 /3 5 2 8 0 /9 0 2 3 0 /4 5 2 4 0 /6 5 2 5 5 /3 0 2 3 5 /3 5 7 0 /9 0 2 3 0 /1 5 B 1 0 m Fi g u re  3 .1 3 : D et ai le d  fi el d  s ke tc h  a n d  p an o ra m ic  p h o to g ra p h  s h o w in g  fa u lt s an d  fo ld s re la te d  to  t h e C at  F au lt  in  a n  o u tc ro p  o f W au g o o la  G ro u p  se d im en ta ry  ro ck s al o n g  C ad ia  H ill  A cc es s Ro ad . L o ca ti o n  o f p h o to g ra p h s sh o w n  o n  fi g u re  3 .7 . B ed d in g  h ig h lig h te d  in  y el lo w . A : D et ai le d  fi el d  s ke tc h  o f th e o u tc ro p . B ed d in g  m ea su re m en ts , i n  t h e fo rm at  s tr ik e/ d ip , a re  s h o w n  a p p ro xi m at el y b el o w  w h er e th ey  w er e ta ke n . Fa u lt  m ea su re m en ts  a re  s h o w n  ab ov e th e m ea su re m en t p o si ti o n . M ea su re m en ts  a re  re la ti ve  to  A u tr al ia n  M ap  g ri d,  A G D  6 6,  a n d  d ip  is  a lw ay s to  t h e ri g h t o f s tr ik e d ir ec ti o n .R am p -f la t fa u lt  g eo m et ry  in  t h e si lt st o n e- d o m in an t p o rt io n  o f t h e o u tc ro p  g iv e w ay  to  fo ld s in  t h e sa n d st o n e- d o m in an t u n it  a p p ro ac h in g  t h e ca t fa u lt . f o ld  h in g e is  ap p ro xi m at el y p ar al le l t o  t h e fa u lt  p la n e.  C at  fa u lt  is  s te ep ly  d ip p in g  a n d  a t a re la ti ve ly  h ig h  a n g le  to  b ed d in g  in  t h e se d im en ta ry  ro ck s. C at  F au lt  ju xt ap o se s sa n d st o n e- d o m in an t tu rb id it es  a g ai n st  s ilt st o n e.  B : d et ai l o f m o st  in te n se ly  d ef o rm ed  z o n e,  in cl u d in g  d ra g  fo ld s. d eb ri s m as si ve b ed d in g fa u lt s A R A M P FL A T 81 N E 1  m 1  m N E A B Fi g u re  3 .1 4 : O p en  fo ld s in  s an d st o n e ab ov e b as em en t fa u lt s. Lo ca ti o n  o f p h o to g ra p h s is  s h o w n  o n  fi g u re  3 .7 . S te re o n et s A  a n d  B  (e q u al  ar ea ) s h o w  b ed d in g  (b la ck ) a n d  fa u lt  (r ed ) m ea su re m en ts  fr o m  W au g o o la  G ro u p  ro ck s ex p o se d  a t th e su rf ac e at  e ac h  p h o to g ra p h  lo ca ti o n . St er eo n et  C  s h o w s th e o ri en ta ti o n  o f t h e C o p p er  G u lly  F au lt  m ea su re d  in  t h e O rd ov ic ia n  B as em en t ro ck s in  t h e C ad ia  H ill  p it . A : O p en  fo ld  fr o m  C o p p er  G u lly  C re ek . F o ld  h in g e p lu n g es  g en tl y to  t h e so u th w es t an d  t re n d s p ar al le l to  t h e u n d er ly in g  C o p p er  G u lly  F au lt . B : A n  o p en  fo ld  d ef in es  t h e sh ap e o f a  h ill si d e n ea r L it tl e C ad ia , r o u g ly  a lo n g  s tr ik e o f t h e C o p p er  G u lly  F au lt . T h is  fo ld  h in g e al so  d ip s g en tl y to  t h e so u th w es t.  O p en  fo ld  g eo m et ry  re p re se n ts  w ar p in g  o f b ed d in g  in  t h e W au g o o la  G ro u p  ro ck s ov er  t h e C o p p er  G u lly  Fa u lt  o r a  re la te d  s p la y th at  h as  n o t b ro ke n  t h ro u g h  t h e co ve r r o ck s. ST ER EO N ET S b ed d in g  =  b la ck fa u lt s =  re d eq u al  a re a C O PP ER  G U LL Y  F A U LT (b as em en t) A B C 82  Intra-Cover Deformation  Over most of Cadia East, the Silurian sedimentary cover sequence generally dips to the west at ~20-40o.  Thickening via low-angle and bedding parallel intra-cover faults and related folding is the dominant mechanism by which shortening is accommodated in the Silurian sedimentary rocks.  Slip has also occurred along bedding planes.  Relatively weak units, such as the siltstone horizons of the turbidite and the micaceous arkose, commonly display sheared fabrics that resulted from bedding-parallel slip along these planes (Figure 3.15).  The magnitude of shortening recorded by individual intra-cover faults and folds is estimated qualitatively based on field observations as being on the scale of meter-to-tens of meters. As mentioned in the previous chapter, the stratigraphy of the Waugoola Group at Cadia East can be essentially divided into upper sandstone-dominated and lower siltstone-dominated sections.  Fault and fold geometries in the upper, sandstone- dominated lithology differ from those in the lower, siltstone-dominated lithology. Folds in sandstone-dominant lithologies are open and faults cut bedding at a low angle.  In the outcrops along the Cadia Hill access road, top-to-the-east thrust faults at a low angle to bedding display a ramp-flat geometry typical of thin-skinned thrusting (Figure 3.16).  Along-strike variations in orientation create wedges of deformed material that pinch out, and meter-scale fault-related folds (Figure 3.16).  Displacement on these shallowly dipping faults is probably on the order of tens of meters or less, although it is impossible to quantify precisely due to the lack of marker horizons and because the fault juxtaposes rocks from the same lithologic package. 83 ES E Fa u lt  Z o n e si lt st o n e sa n d st o n e sa n d st o n e si lt st o n e ar ko se 1 m A B C Fi g u re  3 .1 5 : Ph o to g ra p h ic  e xa m p le s o f b ed d in g  p la n e p ar al le l s lip . A : in te n se  fr ac tu ri n g  o f s ilt st o n e h o ri zo n  in  in te rb ed d ed  s ilt st o n e an d  s an d st o n e fr o m  d ri llc o re . Si lt st o n e is  le ss  c o m p et en t th an  s an d st o n e,  s o  s lip  is  p ar ti ti o n ed  a lo n g  w ea ke r p la n es . G ra d ed  b ed d in g  is  e vi d en t in  t h e g ra d at io n al  n at u re  o f f ra ct u re  d en si ty . B : m ic ac eo u s ar ko se  h o ri zo n s ar e le ss  c o m p et en t th an  t h e en cl o si n g  s ilt st o n es , s o  b ed d in g p ar al le l s lip  in  t h es eu n it s is  e xp re ss ed  a s b ed d in g -p ar al le l f ab ri c d ev el o p m en t.  C :  T h e b ed d in g  p ar al le l f au lt  z o n e in  in te rb ed d ed  s an d st o n e an d  s ilt st o n e fr o m  t h e so u th er n  w al l o f C ad ia  H ill  p it  is  p ro b ab ly  a  s p la y o ff  t h e Fo ys  F au lt . In te n se ly  fr ac tu re d  ro ck  a n d  g o u g e o cc u p y th e fa u lt  z o n e.   P h o to g ra p h  lo ca ti o n  is  s h o w n  o n  fi g u re  3 .7 . 84 SS 1 m 1 m B C sa n d st o n e sa n d st o n e si lt st o n e- d o m in an t si lt st o n e- d o m in an t si lt st o n e- d o m in an t si lt st o n e- d o m in an t si lt st o n e- d o m in an t sa n d st o n e- d o m in an t 1 6 0 /5 0 2 4 5 /8 5 1 6 0 /3 5 1 8 0 /3 5 2 2 5 /7 5 2 3 0 /4 5 2 2 0 /7 0 1 7 0 /3 5 1 8 5 /4 5 1 8 0 /6 5 2 0 0 /5 5 1 9 0 /1 5 2 2 0 /2 5 2 6 5 /9 0 1 7 0 /4 0 1 8 0 /1 0 1 7 5 /4 5 1 8 0 /1 53 1 0 /9 0 1 8 0 /1 51 3 0 /4 0 1 8 5 /1 5 1 7 0 /2 5 1 8 0 /2 0 1 3 5 /4 0 1 7 0 /3 0 1 7 0 /2 02 2 0 /1 5 2 8 0 /9 0 2 5 5 /9 0 1 5 0 /4 5 1 5 5 /4 0 1 6 5 /6 0 1 5 5 /1 5 1 3 0 /4 0 1 8 0 /5 5 1 7 0 /4 5 B C Fi g u re  3 .1 6 : F o ld s an d  t h ru st s in  s an d st o n e an d  in te rb ed d ed  s an d st o n e an d  s ilt st o n e fr o m  a  c o n ti n u o u s ro ad cu t o n  t h e C ad ia  H ill  A cc es s Ro ad . P h o to  lo ca ti o n  sh o w n  o n  fi g u re  3 .7 . A : d et ai le d  fi el d  s ke tc h  o f t h e ro ad cu t.  B ed d in g  m ea su re m en ts , i n  t h e fo rm at  s tr ik e/ d ip , a re  s h o w n  a p p ro xi m at el y b el o w  w h er e th ey  w er e ta ke n . Fa u lt  m ea su re m en ts  a re  s h o w n  a b ov e th e m ea su re m en t p o si ti o n . M ea su re m en ts  a re  re la ti ve  to  A u tr al ia n  M ap  g ri d,  A G D  6 6,  a n d  d ip  is  a lw ay s to  t h e ri g h t o f st ri ke  d ir ec ti o n . Lo ca ti o n s o f p an o ra m ic  p h o to g ra p h s b el o w  (B  a n d  C ) a re  s h o w n  in  a  re d  d as h ed  li n e.   B : p ar al le l t h ru st s b ri n g  s ils to n e- d o m in an t tu rb id it e ov er  sa n d st o n e- d o m in an t tu rb id it e w it h  a  z o n e o f m o re  in te n se  d ef o rm at io n  in  b et w ee n  t h em . C : s an d st o n e th ru st  o ve r s ilt st o n e- d o m in an t tu rb id it e d is p la yi n g  a  ra m p - fla t g eo m et ry . T h ru st s ar e at  a  re la ti ve ly  lo w  a n g le  to  b ed d in g.  C o m p le x fa u lt  a n d  fo ld  g eo m et ry  o cc u rs  w h er e fa u lt s b en d . d eb ri s m as si ve b ed d in g fa u lt s A R A M P FL A T 1 0 m 85  Tight-to-isoclinal folds and chevron folds are common in the lower siltstone- dominant units near faults.  In the Cadia East decline (Figure 3.17), the chevron folds occur in the footwall of the N- striking Gibb fault.  The folds have horizontal to shallowly plunging fold axes that trend parallel to the Gibb fault.  Another tight fold in siltstone related to the Gibb fault outcrops on the southern slope of Sharps Ridge (Figure 3.17). Because of geometric similarities, folds in siltstone at Cadia East (Figure 3.18) might also be related to major basement faults that have not yet been identified in the basement rocks in drillcore. Bedding-parallel thrust faults which occur in the sandstone-dominated upper stratigraphy are not as common in the siltstone.  Instead, steeply dipping faults cross-cut bedding in the siltstone.  These high angle faults are identified in drillcore by rapid changes in the orientation of flaser bedding, and zones of disrupted or chaotic siltstone- in-siltstone breccia (Figure 3.19). Slip along apparently minor detachments in the cover rocks can not be quantified because these surfaces typically do not juxtapose different lithologies.  Where stratigraphic juxtaposition does occur, a lack of laterally extensive marker horizons in the Waugoola Group sedimentary cover rocks makes balancing sections not viable. Likewise, it is not possible to quantify slip along the unconformity and bedding planes.  As a result, attempts at producing measured stratigraphic sections and facies reconstructions have been hindered.  Additionally, the Waugoola Group is preserved discontinuously throughout the district, and erosion between the Devonian and the Mesozoic may have removed portions of the original stratigraphy, so true depositional thickness is unknown. The combination of these factors makes it unlikely that post-mineral shortening can be 86 NE 1mD NE 0.5 m C 0.5 m SW 0.5m A B NE Cadia East Decline (pictured above) red = poles to faultsblack = poles to bedding equal area Sharps Ridge (pictured below) equal area Figure 3.17: Tight fault-related folds in slitstone in the footwall of the Gibb Fault.  Photo locations shown on figure 3.7.  A, B and C are from the Cadia East decline.  D is from Sharps Ridge.  The relationship between folded bedding and related faults in cover rocks at both of these localities is shown on stereonets. 87 0 .5 m S S 0 .5 m A B Fi g u re  3 .1 8 : fo ld ed  s ilt st o n e in  c ad ia  e as t an d  o ri en ta ti o n  d at a.   P h o to g ra p h  lo ca ti o n s ar e sh o w n  o n  fi g u re  3 .7 . B ed d in g  t ra ce s ar e em p h as iz ed  b y b la ck  li n es . D iff er en ce s in  fo ld  m o rp h o lo g y m ay  re p re se n t p ro xi m it y to  t h e co n tr o lli n g  fa u lt .  In  A , t h e re la te d  fa u lt  is  n o t in  t h e p ic tu re , w h er ea s in  B , t h e re la te d  fa u lt  is  t h e st ee p ly  d ip p in g  p o rt io n  to  t h e le ft . Po le s to  b ed d in g  ar e sh o w n  o n  t h e st er eo n et s (e q u al  a re a)  in  b la ck , p o le s to  fa u lt s ar e sh o w n  in  re d . eq u al  a re a eq u al  a re a 88 B X B X Fi g u re  3 .1 9 : Fl as er  b ed d ed  s ilt st o n e fr o m  d ri llc o re  (C E0 97 , 9 5- 10 9 m ). Pu rp le  li n es  in d ic at e b ed d in g  o ri en ta ti o n . B ed d in g  a t 10 2m  is  c h ao ti c. A t 97 m , b ed d in g  d ip s at  a  s te ep  a n g le  re la ti ve  to  t h e co re  a xi s. A t 95 m , s ilt st o n e- in -s ilt st o n e b re cc ia  is  p re se n t. Th er ef o re , i t is  li ke ly  t h at  t h is d ri llh o le  in te rs ec ts  a  fa u lt  o r f o ld  n ea r 9 6m . T h is  s tr u ct u re  is  a  m in o r i n tr a- co ve r f ea tu re , r at h er  t h an  a  m aj o r, b as em en t p en et ra ti n g  fa u lt . 89  quantified using faults and folds measured in the Waugoola Group sedimentary cover rocks.  FAULT REACTIVATION HISTORY  Faults and folds in the Late Silurian Waugoola Group provide evidence for a major deformation event following deposition of the sedimentary cover sequence.  Tilting of bedding down to the west, and west-over-east thrusting on N-S oriented faults suggests that shortening was oriented E-W.  Temporally and kinematically, this makes the Devonian Tabberabberan Orogeny (~380 Ma) the best candidate for post-mineral deformation in the Cadia district (e.g., Powell, 1984). Because the orientation of structures in the sedimentary cover is essentially similar to that of major faults in the basement, it is suggested that all significant displacement was due to shortening after deposition of the Waugoola Group, in the latest Silurian.  However, an equally plausible scenario is that major faults formed earlier in the Ordovician and were subsequently reactivated. A complex tectonic history is recorded in the Cadia district.  Regional deformation began during the Ordovician, and may have produced faults early in the tectonic, even the sedimentary history of the Cadia district.  Once faults form, it is likely that brittle failure will continue to occur along these pre-existing planes of weakness as long as they are oriented favorably relative to the prevailing stress regime (Sibson, 2000). Reactivation of faults elsewhere in the region due to multiple episodes of orogenesis in 90  the Lachlan Fold Belt is well documented in the literature (e.g., Gray and Foster, 1998; Glen and Watkins, 1999; Offler and Gamble, 2002; Glen, 2005). Stratigraphic reconstructions of the Weemalla Formation and the Forest Reefs Volcanics have shown that faults in the Cadia District influenced deposition of Ordovician units (Harris, 2007b).  Additionally, recent advances in understanding the Ordovician stratigraphy in the Cadia District have shown that early faults may have facilitated intrusive emplacement (e.g. Wilson, 2001; Holliday et al., 2002; Kitto, 2005; Harris, 2007b).  Geometric relationships between basement faults and the distribution of Waugoola Group lithologies suggest that many of these faults may have been active prior to deposition of the Silurian sedimentary cover sequence.  Therefore, any related structures in the cover sequence may be attributed to reactivation. The depositional environment for the basal unit of the Waugoola Group has been interpreted as local fault-bounded basins (see chapter 2).  Topography was produced by fault activity during cycles of uplift/subsidence following intrusion and mineralization in the Early Silurian.  The basin geometry, and therefore the distribution of the Waugoola Group, was controlled by pre-existing basement structures.  Stratigraphic thickness variations and lateral facies changes appear to be influenced by N-striking and NE- striking reverse faults.  Three lines of sedimentological evidence exist to support this hypothesis, concerning 1) the spatial distribution of the boulder conglomerate, 2) the role of Sharps Ridge as a pop-up fault block, and 3) the occurrence of Waugoola Group sedimentary rocks in isolated wedges across the Cadia district.   91  Boulder Conglomerate  The boulder conglomerate at the base of the Waugoola Group is restricted to basement lows which are spatially associated with major basement faults.  This is especially evident in Copper Gully and along the Gibb fault (Figure 3.20).  A thick package of boulder conglomerate to the north of Sharps Ridge, known locally as the Hoares Creek Breccia, also represents a local basement low between the Powerline fault system and Sharps Ridge.  This suggests that conglomerates formed at the base of fault scarps from material shed off local highs. Clast populations in the boulder conglomerate include skarn, monzonite porphyry and hydrothermally altered volcanic clasts, reflecting local provenance.  Unaltered clasts of siltstone and limestone, consistent with the lower stratigraphy of the Waugoola cover sequence, also occur in the boulder conglomerate; the polymict nature of some conglomerates suggests that they formed coeval with early phases of deep water sedimentation elsewhere in the Cadia district.  Sharps Ridge  Whereas boulder conglomerate accumulated in basement lows that developed due to vertical fault displacement, basement highs underwent erosion (e.g., Sharps Ridge). Siltstone, which is thick over much of Cadia East is absent from Sharps Ridge. Limestone and boulder conglomerate are also absent.  Interbedded siltstones and sandstones similar to those at the top of the Waugoola stratigraphy elsewhere in the Cadia 92 U n d iff er en ti at ed W au g o o la  G ro u p B o u ld er  C o n g lo m er at e LE G EN D C A D IA  H IL L C A D IA  E A ST Sh ar p s R id ge Co pp er  G ul ly Cad iang ullo ng Gibb C at Po w er lin e N 0 0. 5 1 km Fi g u re  3 .2 0 : M ap  s h o w in g  s p at ia l d is tr ib u ti o n  o f c o n g lo m er at e at  t h e b as e o f t h e W au g o o la  G ro u p  b o th at  t h e su rf ac e an d  in  d ri llc o re . C o n g lo m er at e is  in te rp re te d  a s fa u lt  s ca rp  d ep o si ts . T h is  p ro vi d es in si g h t in to  t h e p al eo g eo g ra p h y o f th e C ad ia  D is tr ic t an d  t h e im p o rt an t ro le  b as em en t fa u lt s p la ye d  in  t h e d ev el o p m en t o f to p o g ra p h y p ri o r t o  L at e Si lu ri an W au g o o la  G ro u p  d ep o si ti o n . 93  district dominate the cover sequence in this area.  This indicates deposition of the Waugoola Group commenced on Sharps Ridge late relative to the rest of the district, once local basins filled and topography was overwhelmed.  Waugoola Group Geometry  Variations in thickness of the siltstone package and differences in the basal unit of the Waugoola Group reflect pre-existing basin architecture.  For example, a relatively thin siltstone package is present in the hanging wall of the Gibb Fault, where it overlies redbeds and boulder conglomerate (Figure 3.21).  However, the siltstone package in the footwall of the Gibb Fault is thicker, and overlies the basal limestone.  Some variations in apparent thickness of the siltstone may reflect structural thickening near the controlling fault.  For example, siltstone in the footwall of the Gibb fault is intensely folded and faulted.  However, tight folds and faults that appear to repeat stratigraphy in the cover rocks have only been observed proximal to major basement faults, whereas these structures are not typical with increasing distance from the controlling basement fault. Therefore, some observed thickness variations across major basement faults probably reflect depositional control.   Therefore, these stratigraphic variations suggest that basin architecture in the late Silurian was controlled by normal faults similar in orientation and configuration to reverse faults present today. Additionally, units high in the Waugoola Group stratigraphy were deposited on relatively low portions of the Forest Reefs Volcanics (see chapter 2).  Deformation and erosion prior to Waugoola Group deposition was responsible for variable relative uplift of 94 ?? ? ?? ? ?? ? Foys Gibb Cat ???? Warreng ong + C A D IA Q U A R R Y C A D IA H IL L C A D IA  E A ST Sh ar p s R id g e Cad ian gul lon g F Gibb C at Co pp er  G ul ly LI T TL E C A D IA Po w er lin e N Pr o je ct io n : A u st ra lia  M ap  G ri d D at u m : A G D 66 ; Z o n e 55 Se ct io n  fr o m  0 68 54 10 , 6 29 54 25 to  0 68 71 00 , 6 29 45 75 0 Sc al e (k m ) 0 .1 0 .2 Fa u lt U n co n fo rm it y Su rf ac e To p o g ra p h y m as si ve  to  t h ic k b ed d ed  q u ar tz  s an d st o n e m as si ve  to  la m in at ed  s ilt st o n e an d  c o ar se -g ra in ed  a rk o se  va ri ab ly  fo ss ili fe ro u s lim es to n e an d  c al ci ru d it e b o u ld er  c o n g lo m er at e O rd ov ic ia n  in tr u si o n s- -p o rp h yr yt ic  m o n zo n it e O rd ov ic ia n  v o lc an ic s Su rf ac e M ea su re m en t In te rp re te d  B ed d in g In te rp re ti ve  C ro ss  S ec ti o n  T h ro u g h  t h e Si lu ri an  S ed im en ta ry  S eq u en ce : C ad ia  E as t A A ‘ A A ‘ N 1 k m LE G EN D in te rb ed d ed  s ilt st o n e an d  s an d st o n e Fi g u re  3 .2 1 : C ro ss -s ec ti o n  sh o w in g  b as em en t fa u lt s an d  re la te d  fa u lt s an d  fo ld s in  W au g o o la  G ro u p  se d im en ta ry  c ov er  ro ck s at  C ad ia  E as t.  Ve rt ic al  sc al e= h o ri zo n ta l sc al e.  S ec ti o n  li n e A -A ’ s h o w n  in  y el lo w  o n  re fe re n ce  m ap . D ri llc o re  lo g s u se d  to  c o n st ra in  t h is  se ct io n  a re  in cl u d ed  in  a p p en d ix  2 . 95  basement rocks, which produced this geometry.  Therefore, basin-bounding faults were actively producing topography at least as early as the Early Silurian, and that topography was maintained throughout much of Waugoola Group deposition in the Cadia district.  SUMMARY AND CONCLUSIONS  Post-mineral shortening in the Cadia district is in part associated with the Devonian Tabberabberan Orogeny, and was accommodated by a complex, anastomosing network of meter-scale to tens-of-meters-scale intra-cover faults and folds in the Silurian sedimentary cover sequence to the Ordovician volcanic complex in the Cadia district. This deformation event was also expressed as reverse separation on basement penetrating faults and slip along the Silurian-Ordovician unconformity.  Faults and folds in the Waugoola Group are similar in orientation to related faults in the Ordovician basement rocks.  Heirarchy of Faults  The stratigraphic and structural framework of the Cadia district indicates that N- striking basement faults formed in the Ordovician as normal sedimentary basin-bounding faults (Harris, 2007a; Wilson, 2003; Figure 3.22).  NE-striking faults were produced in response to fault propagation through the relatively strong intrusions, and apparent fault curvature resulted from connectivity of NE- and older N- striking faults.  These faults were inverted during shortening, so measured offsets of marker beds provide only 96 Pu rp le  F au lt ? C ad ia n g u llo n g W ar re n g o n g North/PC 40 Faults Pyrite Faults? INTRUSION                 (~2km deep) FRV DEPOSITION >445 Ma N MAP VIEW (NOT TO SCALE) X X X X X X XX XXX X INTRUSIONS 442-437 Ma RIFTING ~428-390 Ma TABBERABBERAN INVERSION 380 Ma X X X X X X XX XXX X X X A B C D Figure 3.22: Interpretive map-view timeslices showing the structural evolution of the Cadia District. Geometry of faults and geologic units is idealized. Dates from Wilson et al., 2007. A: The volcanic center migrates eastward across the district, and the Forest Reefs Volcanics are deposited in fault bounded basins. This provides evidence for the earliest structural fabrics in the district. B: Intrusions are emplaced. This phase marks the introduction of major rheological contrasts into the district. Intrusion shown in map view is ~2km below the surface. C: NE-striking faults develop as fault-bounded basins form during rifting.  Waugoola group sedimentary rocks are deposited therein.  Topography is maintained until local basins are filled. Lateral extent of Waugoola Group rocks to the east and west are unknown. D: Rift basins filled with Waugoola Group sediments are inverted during Devonian shortening. Fault connectivity deveolps between NE- and older N- striking faults across the resistant intrusion, producing an apparent curvature in map view. ? HIGH ???? Cat Powerli ne ? ? Copp er X XX X X RIDGEWAY CADIA QUARRY CADIA HILL CADIA EAST X Waugoola Group Fine Grained Marine Sedimentary Rocks Waugoola Group Boulder Conglomerate Fault Scarp Deposits Cadia Intrusive Complex Forest Reefs Volcanics 97  minimum constraints on the magnitude of vertical separation on reverse faults.  E-W shortening during the Devonian Tabberabberan Orogeny was accommodated in the basement along these older faults and produced similarly oriented structures in the Silurian sedimentary rocks.  The inverted faults can be sorted into three categories based on orientation and inferred timing relationships.  The earliest structural fabric to have formed was probably W- to NW- striking faults, such as the PC40 fault at Big Cadia, the North fault at Ridgeway, and the Pyrite faults in Cadia East (Holliday et al., 2002; Wilson et al., 2007b; Harris, 2007a; Figure 3.22a).  Stratigraphic relationships (including thickness variations and sedimentary facies associations) suggest that these structures controlled deposition of Ordovician units in the Cadia district and were important during intrusion and mineralization events (Figure 3.22b; Wilson, 2003; Harris, 2007a).  It is likely that they defined the boundaries of depositional domains during periods of trans-tension early in the tectonic history of the district (>455 Ma). On the south wall of Cadia Hill pit, local W-striking faults produced half-graben basins that contain Waugoola Group sedimentary rocks.  The half-graben basin geometry is preserved because these faults were not inverted during Devonian shortening. However, the similarly oriented (W- striking) Pyrite faults in Cadia East do not appear to control depositional distribution of Waugoola Group rocks, nor are they reflected in faults and folds in the sedimentary cover rocks.  It is therefore interpreted that the Pyrite faults were not reactivated following the Benambran Orogeny in the earliest Silurian. This is probably a result of misorientation of W- and NW- striking fault planes to the regional tectonic stress. 98  N-striking faults of the Cadiangullong fault system and the Gibb fault probably formed as normal faults during extension of the Macquarie Arc (~455 Ma) and remained important in localizing deposition of the Forest Reefs Volcanics (Figure 3.22a).  Rifting following the Benambran Orogeny may have reactivated N- striking faults as normal faults (Figure 3.22c, Figure 3.23a).  Different stratigraphic levels of the Forest Reefs Volcanics preserved at the unconformity across N- and NE- striking faults provides evidence that these faults were important during rifting (Figure 3.23a-c).  This phase of extension generated the basins into which the Silurian Waugoola Group was deposited (Figure 3.22c, Figure 3.23a-c).  Renewed E-W shortening during the Devonian Tabberabberan Orogeny (~380 Ma) initiated reverse motion along major basement faults, and tilted, folded and faulted the Waugoola Group cover rocks (Figure 3.22d, Figure 3.23d-e).  NE- striking faults such as Copper Gully and Cat fault formed as normal faults during post-Benambran extension.  Sharps Ridge and other fault-related topography developed at this time (Figure 3.23b).  Normal slip along these faults during post- orogenic extension influenced basin geometry and controlled deposition of the Waugoola Group.  During the Tabberabberan Orogeny, NE-striking structures experienced reverse separation, which produced similarly oriented folds and faults in the overlying Silurian sedimentary cover rocks.  During this phase of basin inversion, N-striking faults were also reactivated, and curviplanar fault segments developed connecting the N-striking and NE-striking faults.   99 XX X X X X X X X X X X X X UPPER LOWER UPPER X X X X X X XX X UPPER X X X X X X XX X IN V ER SI O N  RI FT IN G A B C D E Figure 3.23:  Tectonic model for rifting and basin inversion in the Cadia District.  A: simple fault geometry at the onset of rifting. A local topographic high forms as a horst in the Forest Reefs Volcanics (green).  B: Erosion exposes the lower stratigraphy of the Forest Reefs Volcanics (dark green) at the unconformity with the overlying Waugoola Group rocks on topographic highs. Upper Forest Reefs Volcanics (light green) are preserved in relative topographic lows. Clastic units at the base of the Waugoola Group, such as the boulder conglomerate (dark purple) and the calicrudite limestone (light blue) are deposited in local half-graben basins as subsidence continues. C: during the sag phase of the rift-sag sequence, siltstone (light purple) and sandstone (pink) is deposited across the district as basins fill. D: basin inversion begins in the Devonian during Tabberabberan shortening. Faults steepen as they are reactivated and blocks are rotated. Folds and faults form in the sedimentary cover rocks that are parallel to basement faults. E: as shortening continues, older faults are abandoned and thrusting is transferred to new faults that cut through the cover rocks. LOWER UPPER UPPER UPPER X X X X X X XX X 100   Basement-Cover Interaction  Faults that controlled the geometry of the Silurian Waugoola Group sedimentary cover sequence were reactivated as reverse faults during Devonian shortening.  Basins into which the Waugoola Group was deposited were inverted.  Differences in the relative strength of basement and cover rocks as well as irregularities in the shape of the unconformity produced complexity at the interface.  During thrusting, basement fault blocks were displaced and rotated relative to one another, which tilted the cover sequence down to the west.  Steep basement faults flatten approaching the surface, up into the cover rocks; shortening is accommodated along multiple detachments including the unconformity and along low angle bedding-parallel faults.  Deformation is dispersed through the cover sequence via a complex network of relatively small-scale faults and folds that are related to major faults at depth. The intensity of deformation in the sedimentary cover rocks increases approaching major basement structures.  Therefore, structures measured in the Waugoola Group sedimentary cover rocks can be used to make inferences about the geometry of the underlying basement.  Basin Inversion  Basin inversion occurs when shortening is superposed on an extensional environment (e.g. Williams et al., 1989; Gelabert et al., 2004; Camus, 2006; Butler et al., 2006; Zanchi et al, 2006; Konstantinovskaya et al., 2007).  This change in deformation reflects a change in orogen-scale tectonics.  In extensional settings, normal faults cause 101  rotation of older rocks in fault blocks that step out toward the margins of the developing basin along a series of progressively flatter faults (e.g. Konstaninovskaya et al., 2007, and references therein).  The sedimentary cover sequence is deposited in the basin at this time.  When shortening commences, basin-bounding faults are reactivated as reverse faults.  Older basement rocks are rotated and thrust over sedimentary cover rocks along faults that rotate to steeper orientations as the foreland propagates and new faults are formed in the footwall of older faults (Camus, 2002; Camus, 2003).  Reactivated basement faults typically flatten as they intersect the sedimentary cover sequence, and may branch out into a number of smaller faults (Camus, 2006).  The sedimentary cover sequence is faulted and folded around the basement fault, while the basement blocks behave as relatively rigid blocks that are displaced relative to one another via reverse faults (e.g. Chambers et al., 2004; Molinaro et al., 2005; Grey et al., 2006; Mouthereau and Lacombe, 2006; and references therein).  Deformation of basement blocks typically entails both a rotational and a translational component.  Basin inversion is globally recognized and can be documented at a variety of scales (Figure 3.24). In the Cadia district, the geometry of basement and cover fault interaction is consistent with the basin inversion model.  Basement faults control the orientation and distribution of faults and folds in the sedimentary cover sequence.  Relatively steep basement faults flatten at the unconformity and fan into multiple low-angle detachments. Across the district, basement faults progressively steepen toward the west and northwest, i.e., toward the hanging wall of the next thrust. 102 Re g io n al Lo ca l Ex te n si o n Ex te n si o n Ex te n si o n C o m p re ss io n C o m p re ss io n C o m p re ss io n C o m p re ss io n C o m p re ss io n A B X X X X Fi g u re  3 .2 4 : b as in  in ve rs io n  m o d el s m o d ifi ed  fr o m  K o n st an ti n ov sk ay a et  a l, 20 07  (A ) a n d  C am u s, 20 06  (B ). A : O ro g en -s ca le  p h as es  o f b as in  in ve rs io n . Ex te n si o n  le ad s to  n o rm al  fa u lt in g  a n d b as in  d ev el o p m en t. B as in s fil l p ro g re ss iv el y as  e xt en si o n  c o n ti n u es , a n d  n o rm al fa u lt s ar e ro ta te d  to  fl at te r o ri en ta ti o n s in th e ce n te r o f t h e b as in  a s n ew  fa u lt s fo rm o n  t h e m ar g in s. W h en  c o m p re ss io n co m m en ce s, n o rm al s fa u lt s ar e re ac ti va te d as  re ve rs e fa u lt s. A s co m p re ss io n co n ti n u es , f au lt s b re ak  t h ro u g h  t h e se d im en ta ry  c ov er  ro ck s an d  fl at te n al o n g  t h e m ar g in s. A  t w o -s id ed  o ro g en ic w ed g e is  t h e re su lt , w it h  s te ep er  t h ru st s at  t h e co re  o f t h e o ro g en  a n d  fl at te r fa u lt s to w ar d  t h e m ar g in s. B : d et ai l o f b as in  in ve rs io n  o n  h al f- g ra b en  g eo m et ry p ro d u ce d  lo ca lly  a t a si n g le  fa u lt , s im ila r to  t h e o n e sh o w n  in  p o si ti o n  X  o n  fi g u re A . F o llo w in g  b as in  d ev el o p m en t an d se d im en ta ry  c ov er  s eq u en ce  d ep o si ti o n , co m p re ss io n  fi rs t ca u se s fo ld in g  o f c ov er se q u en ce  ro ck s b ef o re  fa u lt s b re ak th o u g h . A s sh o rt en in g  c o n ti n u es , d ef o rm at io n  o f t h e co ve r s eq u en ce in te n si fie s an d  t h e fo ld -t h ru st  g eo m et ry b ec o m es  m o re  c o m p le x.  In  t h e C ad ia D is tr ic t, h al f- g ra b en  b as in s o n  t h e so u th er n  w al l o f t h e C ad ia  H ill  p it  a re  n o t in ve rt ed  b ec au se  e as t- d ip p in g  fa u lt s ar e n o t re ac ti va te d . H o w ev er , m aj o r w es td ip p in g re ve rs e fa u lt s, su ch  a s th e C ad ia n g u llo n g  F au lt  a n d  C at  fa u lt p ro d u ce d  s im ila r f au lt  g eo m et ry  to  t h at p re d ic te d  in  t h e C am u s m o d el . 103  Chapter Four:  Conclusions  INTRODUCTION  In the Cadia District, as with many other mineralized systems worldwide, study is focused on the intrusive history, alteration assemblages, and mineralization events (e.g. Holliday et al., 2002; Wilson et al., 2007a; Wilson et al., 2007b).  However, this provides information on only a small portion of the district history.  It is important to develop a holistic model that accounts for pre- syn- and post mineral evolution of the district in order to fully understand the ore deposits, especially in areas with a complex geologic history. Stratigraphic reconstructions of the Ordovician basement in the Cadia District have improved the district scale structural model (e.g. Wilson, 2003; Harris, 2007a). Likewise, refining the stratigraphy of the Waugoola Group sedimentary cover sequence has been critical in understanding post-mineral deformation.  Recognition of facies variations, particularly in the basal unit, has provided constraints on the paleogeography of the district, and has demonstrated the importance of basement faults in controlling basin geometry (Wilson, 2003; Harris, 2007b). Based on the stratigraphy of the Waugoola Group cover rocks, it is possible to better understand the faults and folds at the surface and the relationship to basement faults.  At the unconformity, moderate-to-steeply dipping basement faults flatten and branch out into a complex network of detachments that disrupt the tilted sedimentary cover package.  This geometry suggests that post-mineral deformation was characterized 104  by basin inversion.  Therefore, not only can the faults and folds in the Waugoola Group sedimentary cover sequence be used to characterize post-mineral deformation and orebody dismemberment, but they provide new insight into the protracted influence of basement faults on the structural architecture of the Cadia District.  CONCLUSIONS  1) Paleo-topography related to basement faults controlled distribution of Silurian sedimentary lithologies.  Major, through-going basement structures controlled basin geometry, defined depositional regimes, and influenced facies distribution in the Cadia District.  In particular, half-graben basins and fault-scarps have been recognized as sedimentological boundaries.  Variations in the basal unit across the Cadia District provide evidence that significant topography was present at the onset of Waugoola Group deposition in the Late Silurian. The Waugoola Group in the Cadia District represents a rift-sag sequence.  Fault related topography that controlled the deposition of lower clastic units of the Waugoola Group stratigraphy in the Cadia District was overwhelmed by marine sedimentation as local basins filled.  The transition from isolated basins into regional marine transgression recorded by the Waugoola Group represents the thermal evolution of the extending crust.  2) Orientation of structures in the sedimentary cover sequence is controlled by basement faults.  Major faults in the basement rocks of the Cadia District are similar in orientation and spatially related to faults and folds in the Waugoola Group cover rocks. 105  Faults and folds in the cover succession formed as a result of E-W directed shortening during the Devonian Tabberabberan Orogeny.  Inversion of sedimentary basins occurred at this time, and N- and NE-striking basement faults experienced reverse movement. Thrusting along basement faults and rotation of basement fault blocks resulted in tilting of the Waugoola Group sedimentary cover rocks down to the west.  Steeply dipping basement faults flatten at the unconformity and shortening is accommodated in the cover rocks along slip surfaces at a low angle to bedding, including the unconformity. Where basement faults break through, deformation of the cover rocks is intense.  Intra- cover faults and folds are parallel to the controlling basement fault.  Where basement faults do not penetrate the cover rocks, open folds are produced.  Differences in fault and fold geometry reflect rheological contrasts between adjacent rocks.  3) Basement faults formed prior to deposition of the Waugoola Group and have probably been reactivated multiple times throughout the tectonic history of the Cadia District.  Major faults in the Cadia District can be grouped into three sets based on orientation and relative timing relationships.  The earliest faults were W- and NW- striking and are parallel to the Lachlan Transverse Zone.  These faults were important in mineralization at Ridgeway and Cadia East (E.g. Holliday et al., 2002; Wilson, 2003; Wilson et al., 2007b).  Additionally, the NW- elongation of the Cadia Intrusive Complex and the NW-trending corridor in which deposits are localized at the district-scale suggest that this fabric developed as early as ~435 Ma (Wilson, 2003; Harris, 2007a). N-striking faults, including the regionally significant Cadiangullong Fault System, formed during deposition of the Forest Reefs Volcanics.  These faults controlled the 106  distribution of volcanic facies across the district, and therefore formed at least as early as the late Ordovician-early Silurian (Harris, 2007b).  NE-striking faults in the Cadia District formed during rifting as a result of difficulty propagating N-striking faults through the relatively strong Cadia Intrusive Suite.  NE- and N- striking faults connected during basin inversion, producing the curved step-over fault geometry preserved today. Intrusive rocks associated with mineralization in the Cadia District and the enclosing host rocks were uplifted and eroded in the early Silurian.  A transition to an extensional environment occurred when rifting commenced at ~428 Ma.  Basin evolution in the Cadia District is recorded by the Late Silurian Waugoola Group.  N- and NE- striking faults experienced normal slip during post-mineral extension and controlled the geometry of basins into which Waugoola Group rocks in the Cadia District were deposited.  Subsequent Devonian shortening during the Tabberabberan Orogeny resulted in basin inversion and produced faults and folds in the cover sequence parallel to underlying basement faults.  Because W- striking faults were not oriented favorably to the E-W shortening direction, they were not reactivated at this time, and are therefore not manifested in the cover sequence.        107  IMPLICATIONS  Post-mineral Deformation and Orebody Dismemberment  Post-mineral deformation affects the preservation potential of ore deposits, and must therefore be taken into account when considering exploration strategies. The dismemberment of ore systems by faults has been documented globally in both extensional and compressional settings.  For example, normal faults related to Basin-and- Range extension in Nevada have dismembered and effectively rotated the Yerington porphyry system 90o (e.g. Dilles and Proffet,1995).  The Potrerillos deposit in Chile is dismembered by thrust faults (Davidson et al., 1991; Thompson et al., 2004).  Similarly, orebody dismemberment due to post-mineral deformation has played an important role in the Cadia District.  Mineral deposits at Ridgeway, Cadia Hill, and Cadia East are separated by major basement faults with a prolonged history of reactivation in extensional and compressional environments.  Reconstructions of the enclosing stratigraphy show that each deposit represents a different level in the intrusive system (e.g. Holliday et al., 2002; Wilson et al., 2006; Harris, 2007a).  N- and NE-striking faults, including the Cadiangullong and Gibb faults, are responsible for dismemberment of the ore system.  Post-mineral slip along these faults determines the preservation potential of ore deposits in the Cadia District.  However, present-day configuration of faults and apparent displacement does not necessarily represent only post-mineral deformation, because faults were active prior to mineralization and were subsequently reactivated.  Therefore, it is critical to 108  understand the role of these faults throughout the history of the district to constrain the magnitude of orebody dismemberment.  Relationships in the Waugoola Group sedimentary cover sequence were instrumental in recognizing the importance of fault reactivation, and will continue to provide insight into post-mineral deformation as the structural model for the Cadia District evolves.  Using Structure in the Cover Sequence to Understand the Basement  Faults and folds in the Waugoola Group rocks are related to underlying basement faults.  Therefore, the orientation and nature of faults and folds in the Silurian sedimentary cover sequence can be used as a predictive tool to identify Ordovician faults at depth.  Basement faults are expressed in the cover rocks as steep to moderately dipping planes that cut Waugoola Group bedding at a high angle and juxtapose different units in the Waugoola Group stratigraphy.  Thrust faults in the cover rocks strike parallel to, and dip toward controlling basement faults. Folds in the cover rocks are commonly associated with underlying basement faults.  Where basement faults fail to penetrate the cover rocks, open folds are present. Local, minor folds related to basement- and intra-cover faults have also been identified. Folds in siltstone are generally tighter than folds in sandstone.  Fold hinges trend parallel to underlying basement faults.  Asymmetrical folds may provide a sense of vergence, with the steeper limb closer to the related fault.  The intensity of folds and faults in the cover rocks increases proximal to basement faults. 109  There are some limitations associated with using faults and folds measured at the surface in the sedimentary cover rocks to identify basement faults.  First, the dip of basement faults is steeper than corresponding faults in the cover rocks.  Consequently, faults at the surface can not be projected through the basement.  If the thickness of the cover rocks is known, faults measured at the surface can be projected to the unconformity.  Likewise, basement faults measured in drillcore cannot be projected through the cover rocks. Second, only faults that were reactivated following deposition of the Silurian Waugoola Group can be identified using faults and folds in the cover rocks.  W-striking faults, such as the Pyrite faults at Cadia East, do not appear in the cover rocks.  As a result, W-striking faults were not reactivated during post-mineral deformation.  This is probably due to the misorientation of these faults to the dominant shortening direction. While this provides insight into the hierarchy of faults in the Cadia District, it restricts the predictive capability of faults and folds in the cover rocks. In addition to structural measurements, stratigraphic observations in the Waugoola Group sedimentary cover sequence can provide insight into faults in the underlying basement.  Boulder conglomerate at the base of the Waugoola Group is interpreted as fault scarp deposits.  Therefore, where the boulder conglomerate is present at the surface, basement faults are probably present at depth.  Variations in the basal unit across the district reflect different depositional environments due to fault related topography, and therefore may also delineate faults. Because basement faults were reactivated during post-mineral deformation, analysis of faults and folds in the cover rocks can help to understand the structural 110  architecture of the district.  Additionally, structural data obtained from surface exposed of the Waugoola Group sedimentary cover sequence can be used to better design drill programs, identify potential geotechnical problems, and target subsurface water sources.  FUTURE WORK  Refining the stratigraphy of the Waugoola Group in the Cadia District has improved the understanding of paleogeography in the Silurian.  Further improvements in the stratigraphy may continue to constrain the timing of deformation and basin evolution in the Cadia District.  For example, a detailed study of carbonate facies in the basal limestone and calcirudite across Cadia East may provide insight into local irregularities in the unconformity.  Additionally, improved age constraints on depositional stages can be obtained through continued fossil work and zircon provenance studies in sandstone and arkose units.  Finally, comparison of Waugoola Group stratigraphy from the Cadia District with regional occurrences can broaden the understanding of rifting and basin development during the Silurian and place the Cadia District into a tectonic context. Testing the predictive capability of faults and folds in the cover rocks by continued surface mapping and comparison with basement faults identified in drillcore data is a logical next step.  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Measurements (in degrees) and corresponding coordinates (given as Easting and Northing) are in Australia Map Grid projection, using the datum AGD66.  Strike and dip was measured with a Brunton compass, and measurements were rounded in the field to the nearest 5o.  Strike measurements were always taken so that the plane being measured dipped to the right (for example, N- striking planes dip to the E).  Where measurement or lithology was uncertain, it is indicated with a question mark. The “station” column indicates a general geographic area for measurement location.  CE=Cadia East, CG=Copper Gully, RC=roadcutting from the Cadia Hill access road, SR=Sharps Ridge, SW=southern wall of Cadia Hill pit, EW=eastern wall of Cadia Hill pit, DP=drill pad (Cadia East or Sharps Ridge). The “lithology” column indicates what rock type bedding was measured in. Where a bedded contact was measured, units on either side of the contact are separated with an underscore, and the upper unit is listed first.  Abbreviations are as follows: si=siltstone, ss=sandstone (undifferentiated), siturb=siltstone-dominant interbedded siltstone and sandstone, ssturb=sandstone-dominant interbedded siltstone and sandstone, mss=massive sandstone, redsi=red siltstone, blksi=black shale, bc=boulder conglomerate, sibx=brecciated siltstone, ord=Ordovician basement (undifferentiated), ark=arkose. The “measurement” column indicates what feature was measured at each location. Abbreviations used are: bed=bedding, bedcontact=bedding-parallel contact, bedfault=bedding parallel fault, bedfaultcontact=bedding parallel faulted contact. Uncertainty is indicated with a question mark.       126 station lithology measurement strike dip Easting Northing CE si bed 230 80 686752 6295005 CE siturb bed 25 45 686730 6294817 CE si bed 25 35 686738 6294812 CE ss bed 220 45 686101 6295123 CE siturb bed 5 70 686013 6295254 CE siturb bed 325 45 686012 6295238 CE siturb bed 190 45 686119 6295163 CE ss bed 190 25 686387 6295440 CE ss bed 190 40 686428 6295363 CE ss bed 170 40 686472 6295413 CE si bed 175 45 686505 6295668 CE ss bed 190 25 686389 6295574 CE ss bed 155 30 686290 6295042 CE siturb? bed 200 50 686229 6295083 CE ss bed 125 30 685819 6295246 CE ss bed? 330 65 685736 6295315 CE ss bed 200 90 686131 6295632 CG ss bed 165 45 687610 6296630 CG ss bed 145 50 687570 6296731 CG ss bed 135 60 687574 6296729 CG ss bed 135 55 687573 6296726 CG ss bed 20 50 687572 6296720 CG ss bedfault 40 85 687557 6296666 CG ss_siturb bedcontact 180 25 687570 6296680 CG ss bed 170 40 687527 6296620 CG ss bed 160 25 687499 6296542 CG ss bed 160 20 687449 6296559 CG ss bed 150 25 687451 6296550 CG ss bed? 230 70 687289 6296491 CG ss bed? 250 10 687289 6296491 CG ss bed? 20 60 687398 6296503 CG ss bed 220 20 687405 6296490 CG ss bed 225 25 687375 6296452 CG ss bed 200 10 687349 6296409 CG ss bed 230 50 687346 6296408 CG ss bed 200 40 687355 6296359 CG ss bed 80 65 687403 6296346 CG siturb bed 230 30 687456 6296289 CG ss bed 225 30 687432 6296250 CG ss bed 210 30 687415 6296243 CG ss bed 245 60 687376 6296284 CG ss bed 220 45 687401 6296305 CG ss bed 230 40 687402 6296323 CG ss bed 250 60 687356 6296309 CG ss bed? 240 50 687352 6296299 CG siturb bed 95 65 687355 6296317 CG ss bed? 60 45 687346 6296265 127 station lithology measurement strike dip Easting Northing CG ss bed? 355 25 687283 6296241 CG siturb bed 80 35 687282 6296291 CG ss bed? 235 25 687252 6296290 CG ss bed? 265 25 687233 6296276 CG ss bed? 310 25 687185 6296293 CE si bed 15 55 686698 6295432 CE si bed 240 45 686695 6295432 CE si bed 270 40 686699 6295437 CE si bed? 225 30 686659 6295445 CE siturb? bed? 10 60 686703 6295341 CE ss?si? bed 190 15 686663 6295297 CG sibx?bc? bed? 290 35 686502 6295858 CG si bed 255 45 686479 6295853 CG si_ark bed 145 35 686426 6295791 CG si_ark bed 140 40 686405 6295774 CG siturb bed 200 50 686310 6295726 CG ss bed 200 45 686303 6295725 CG ss bed 215 55 686242 6295802 CG ss bed? 20 35 686329 6295811 CG ss bed? 250 40 686370 6295842 CG ss bed 220 20 686392 6295888 CG ss bed 230 35 686431 6295930 CG ss bed? 140 20 686489 6295981 CG si?siturb? bed 180 80 686634 6296050 CG ss? bed 270 40 686727 6296120 CG ss bed? 350 70 686740 6296127 CG ss bed? 230 85 686749 6296123 RC ssturb bed? 215 45 686193 6294910 RC ssturb bed 220 65 686198 6294890 RC ssturb bed 190 45 686195 6294891 RC si bed 30 75 686203 6294889 RC ssturb? bed 240 35 686208 6294872 RC si bed 215 15 687034 6294703 RC si bed 205 30 686884 6294649 RC si bed 200 40 686866 6294648 RC si bed 205 25 686857 6294649 RC si bed? 190 40 686823 6294654 RC si bed 30 55 686787 6294664 RC si bed 35 65 686785 6294664 RC si bed 200 65 686711 6294698 RC si bedfault 185 70 686600 6294751 RC ark?ss? bed 230 15 686600 6294752 RC si bed 200 25 686593 6294758 RC si bed 230 15 686532 6294784 RC ssturb? bed 220 30 686489 6294792 RC si bed 225 15 686544 6294788 RC si bed 210 25 686526 6294802 128 station lithology measurement strike dip Easting Northing RC ssturb bedfaultcontact 240 10 686516 6294807 RC si bed? 250 55 686387 6294866 RC si bed 190 20 686397 6294868 RC si bed 190 25 686409 6294866 RC si?ssturb? bed 190 10 686417 6294872 RC si?turb? bed 180 15 686420 6294871 RC si?turb? bed 180 5 686425 6294871 RC si? bed 185 15 686427 6294878 RC si? bed 200 35 686431 6294881 RC ssturb? bed 210 5 686440 6294880 SR ss bed? 290 30 687031 6296652 SR ss bed? 100 16 687002 6296634 SR ss bed? 220 60 686941 6296625 SR ss bed? 20 20 686940 6296620 SR ss bed 35 45 686829 6296548 SR ss bed? 70 30 686820 6296504 SR ss bed 150 40 686801 6296475 SR ss? bed? 135 70 686728 6296474 SR ss bed? 220 25 686633 6296496 SR ssturb? bed? 140 55 686628 6296494 SR ssturb? bed? 220 60 686619 6296493 SR ssturb? bed? 115 45 686592 6296504 SR ssturb bed 110 45 686578 6296505 SR si bed 60 45 686444 6296552 SR ss bed 145 35 686439 6296534 SR ss bed 145 25 686437 6296533 SR ss bed 150 30 686408 6296524 SR ss bed 110 25 686355 6296518 SR ss bed 130 30 686316 6296498 SR ss bed? 200 35 686275 6296547 SR ss bed 185 25 686181 6296541 SR ss? bed? 330 35 686087 6296563 SR siturb? bed 250 90 686077 6296557 SR ss? bed 90 35 686080 6296557 SR ss bed 110 60 686072 6296546 SR siturb bed 270 5 686074 6296506 SR ssturb? bed 220 25 686072 6296495 SR ss bed 175 25 686100 6296483 SR ss bed 110 10 686112 6296455 SR ss bed 180 25 686136 6296454 SR ssturb? bed 170 30 686173 6296440 SR ssturb bed 170 25 686187 6296432 SR ssturb bed 170 35 686204 6296425 SR ssturb bed 185 30 686223 6296419 SR ssturb bed 185 40 686223 6296416 SR siturb bed 170 30 686227 6296403 SR ssturb? bed 130 25 686262 6296401 129 station lithology measurement strike dip Easting Northing SR ssturb bed 150 10 686265 6296400 SR siturb bed 170 25 686271 6296398 SR ss bed 155 35 686271 6296388 SR ss bed 170 35 686316 6296367 SR ss bed 140 35 686326 6296386 SR ss bed? 130 30 686392 6296416 SR ss bed? 50 40 686413 6296366 SR ss bed? 255 25 686409 6296350 SR ss bed? 240 15 686440 6296371 SR ss bed? 10 25 686673 6296256 SR ss bed? 240 40 686714 6296296 SR siturb bed 30 40 686206 6296053 SR ss?turb? bed? 170 40 686254 6296087 SR ssturb bed 115 35 686270 6296075 SR si bed 125 45 686275 6296061 SR si bed 105 60 686275 6296053 SR si bed 235 15 686275 6296020 SR si bed 80 35 686279 6296021 SR si bed 355 20 686287 6296011 SR ss bedfault 40 90 686256 6295803 SR si bed 30 85 686259 6295800 SR si?turb? bed 70 40 686232 6296281 SR siturb bed 200 70 686207 6296294 SR siturb bed 175 30 686198 6296305 SR siturb bed 155 20 686196 6296302 SR si? bed 155 40 686188 6296305 SR siturb bed 175 20 686171 6296310 SR siturb bed 160 20 686155 6296306 SR ssturb bed 160 20 686148 6296312 SR siturb bed 170 10 686130 6296321 SR ss?turb? bed 160 10 686112 6296324 SR ss bed 190 40 686105 6296328 SR siturb bed 180 25 686197 6296294 SR ss?turb? bed? 60 40 686175 6296265 SR ss bed 65 50 686151 6296206 SR siturb bed 55 70 686180 6296166 SR si? bed? 55 60 686172 6296140 SR ss bed 40 30 686162 6296133 SR si bed 45 50 686159 6296084 SR si bed 45 45 686159 6296090 SR ss bed 45 45 686172 6296070 SR ss bed 35 40 686185 6296063 CG ss bed? 165 20 687597 6296618 CG ss bed? 175 25 687554 6296626 CG ss bed 155 30 687556 6296626 CG ss bed? 10 60 687561 6296629 CG ss bed? 10 70 687559 6296637 130 station lithology measurement strike dip Easting Northing CG ss bed 210 30 687558 6296662 CG ss bed 210 40 687562 6296670 CG ss bed 30 60 687563 6296719 CG ss bed 150 45 687577 6296725 CG ss bed 150 55 687573 6296732 CG ss bed 280 55 687582 6296734 CG ss bed 135 60 687585 6296738 CG siturb? bed?fault? 325 75 687689 6296667 CG siturb bed 145 90 687688 6296674 CG si? bed 205 30 687690 6296577 CG si? bed? 165 60 687753 6296747 CG siturb? bed? 20 80 687741 6296747 CG ssturb? bed? 310 40 687734 6296769 CG ssturb bed 310 45 687726 6296775 CG ssturb bed 125 50 687718 6296797 CG ssturb bed 320 45 687727 6296798 CG si? bed 315 40 687723 6296784 CG siturb? bed 290 35 687723 6296774 CG siturb bed 270 45 687725 6296767 CG ss bed 290 40 687718 6296759 CG siturb bed 295 50 687718 6296755 CG si?turb? bed 290 40 687715 6296735 RC si bed 220 25 687680 6296514 RC si bed 190 35 687680 6296518 RC si bed 130 25 687678 6296512 RC si bed 185 35 687675 6296508 RC si bed 205 35 687677 6296500 RC si bed 245 35 687674 6296491 RC si? bed 200 20 687673 6296477 RC siturb? bed 240 55 687674 6296478 RC ssturb? bed 230 55 687673 6296468 RC ssturb? bed 155 35 687674 6296459 RC si?turb? bed 140 30 687674 6296459 RC si bed 215 60 687638 6296458 RC ss bed 150 45 687639 6296450 RC ssturb bed 70 80 687636 6296434 EW mss bed 185 40 685973 6296609 EW siturb bed 175 30 685959 6296608 EW ss bed 155 30 685936 6296606 EW mss bedfault 175 30 685866 6296587 SW ss bed? 95 20 685495 6295452 SW bc_ord bedcontact 110 45 685779 6295558 EW si bedfault 80 65 686034 6296154 CG si? bed 275 40 686511 6295846 CG mss bed 160 30 686395 6295779 CG ss bed 145 20 686360 6295638 DP ss bed 140 25 686452 6295218 131 station lithology measurement strike dip Easting Northing DP ss bed 140 25 686530 6295300 DP sst bed 195 35 686550 6295394 DP sst bed 140 20 686635 6295418 DP si bed 150 10 686673 6295294 DP si bed 140 30 686727 6295273 RC ss bed 215 15 687017 6294691 CE ss bed? 250 25 686590 6294952 CE ss_si bedcontact? 240 15 686556 6294898 CE sst bed 210 30 686740 6294957 CE si bed 215 25 686567 6294992 CE ssturb? bed 155 20 686470 6295058 CE sst bed 165 30 686344 6295076 CE ssi bed 200 60 686327 6295079 CE si? bed 165 25 686325 6295104 CE ssturb bed 150 70 686291 6295097 EW sst bed 220 45 685993 6296461 EW sst bed 115 40 685992 6296458 CE mss bed 180 35 686097 6295063 CE mss bed 190 45 686017 6295262 CE mss bed 215 45 686048 6295298 CE ss bed 185 35 686126 6295227 CE ss bed 55 10 686099 6295305 CE ss bed 210 40 686073 6295204 CE ss bed 175 20 686175 6295537 CE mss bed 205 20 686243 6295580 CE ss bed 185 30 686359 6295463 CE si? bed? 270 25 686425 6295634 CE si? bed 175 30 686501 6295661 CE ss bed 190 45 686414 6295550 CE ss bed 20 25 686392 6295393 CE mss bed 200 35 686539 6295453 CE mss bed 180 40 686575 6295503 SR mss bed? 15 30 686534 6296273 SR ss bed? 5 70 686510 6296206 SR mss bed? 330 25 686459 6296102 SR mss bed? 350 70 686435 6296055 SR ssturb bed 45 60 686367 6296041 SR mss bed? 315 55 686344 6296077 SR mss bed 120 35 686337 6296093 SR ssturb bed 45 60 686412 6296115 SR mss bed 185 30 686406 6296139 SR mss bed 140 45 686398 6296140 SR mss bed 135 15 686124 6296255 SR mss bed 50 30 686156 6296125 SR mss bed 35 40 686168 6296072 SR siturb bed 30 45 686202 6296046 SR blksi? bed 105 60 686261 6296048 132 station lithology measurement strike dip Easting Northing SR blksi bed 45 15 686286 6296033 SR si bed 55 20 686282 6296036 SR ss bed 65 60 687044 6296654 SR ss bed 60 60 687011 6296610 SR ss bed? 125 25 686992 6296602 SR ss bed 60 60 686960 6296607 SR ss bed 60 35 686913 6296535 SR ss bed 65 20 686882 6296579 SR ss bed 100 20 686849 6296514 SR ss bed? 275 40 686725 6296452 SR ss bed 60 50 686675 6296469 SR ss bed? 280 30 686575 6296454 SR ss bed 65 30 686431 6296486 SR ss bed 225 25 686396 6296402 SR ss bed 235 25 686413 6296364 SR si bed 70 20 686228 6296277 SR si bed 185 30 686195 6296280 SR ss bed 65 60 686196 6296264 SR ss bed 165 15 686125 6296267 SR ss bed 170 15 686135 6296290 RC ss bed 205 20 687064 6294700 CG mss bed 175 25 687596 6296612 CG mss bed 145 30 687557 6296620 CG mss bed 140 30 687554 6296631 CG mss bed 175 35 687558 6296603 CG mss bed 170 40 687545 6296590 CG mss bed 205 45 687546 6296575 CG mss bed 145 20 687503 6296565 CG mss bed 125 20 687402 6296538 CG mss bed 155 30 687480 6296537 CG mss bed 150 20 687473 6296530 CG mss bed 120 25 687459 6296528 CG mss bed 225 25 687455 6296527 CG mss bed 175 70 687454 6296522 CG mss bed 220 35 687451 6296522 CG mss bed 140 25 687451 6296527 CG mss bed 180 20 687450 6296520 CG mss bed 170 20 687436 6296523 CG mss bed 230 40 687432 6296520 CG mss bedfault 145 40 687430 6296520 CG mss bed 140 20 687427 6296522 CG mss bed 220 25 687412 6296518 CG mss bed 335 45 687420 6296504 CG mss bed 275 50 687413 6296518 CG mss_siturb bedcontact 230 45 687395 6296504 CG ss_siturb bedcontact 225 40 687409 6296498 CG ss_siturb bedcontact 220 25 687406 6296498 133 station lithology measurement strike dip Easting Northing CG ss_siturb bedcontact 220 35 687387 6296494 CG ss_siturb bedcontact 210 35 687394 6296475 CG ss_siturb bedcontact 205 35 687384 6296475 CG ss_siturb bedcontact 220 25 687384 6296476 CG ss_siturb bedcontact 215 25 687371 6296451 CG mss? bed 210 35 687365 6296411 CG ssturb bedcontact 185 25 687364 6296428 CG mss bed 210 25 687350 6296413 CG mss bed 215 40 687392 6296394 CG mss bed 220 25 687381 6296392 CG mss bed 210 50 687354 6296372 CG mss bed 200 45 687342 6296343 CG mss bed 90 75 687334 6296315 CG mss bedfault 80 65 687344 6296319 CG si bedfault 85 70 687326 6296293 CG siturb? bed 195 15 687319 6296282 CG siturb? bed 225 60 687178 6296268 CG ss? bed 115 50 687155 6296365 CG ss bed 180 20 687198 6296211 CG ss bed 105 60 686756 6296117 CG ss bed 100 45 686731 6296113 CG si_bc? bedcontact 290 50 686715 6296007 CG ss? bed 220 35 686184 6295693 CG siturb? bed 50 85 686215 6295786 CG mss? bed 235 70 686221 6295780 CG bc bed? 155 20 686207 6295875 CG mss bed? 70 40 686116 6296005 CG mss bed 125 30 686144 6295862 CG si bed 210 35 686143 6295612 CG mss bed 195 30 686193 6295569 CG mss bed 165 30 686228 6295559 CG mss bed 190 35 686234 6295635 CG mss bed 150 35 686139 6295610 CG mss_ssturb bedcontact 45 85 686258 6295796 CG siturb? bed 255 50 687309 6296288 CG ss bedfault 290 45 687307 6296300 CG mss bed 175 35 687555 6296625 EW mss bed 90 60 686016 6296154 RC siturb bed 230 15 686331 6294893 RC si bed 240 30 686366 6294877 RC si bed 165 10 686548.6 6294764 RC ssturb_si bedcontact 205 15 686507.6 6294791 RC ssturb? bed 215 20 686460.8 6294817 RC si bed? 110 10 686714.8 6294686 RC ssturb? bed? 60 15 686695.4 6294696 RC ss? bed?fault? 210 15 686648.5 6294720 CG si bed 290 45 686465.6 6295863 134 station lithology measurement strike dip Easting Northing CG si bed 145 10 686435.7 6295850 CG si bed 155 20 686371 6295753 EW ssturb? bed 310 10 685980 6296393 EW mss bed 195 25 685960.9 6296435 EW mss bed 215 40 685941.7 6296490 CG sst bed 205 45 686340.9 6295749 CG mss bed 205 25 686265 6295748 CG mss bed 180 20 686213.3 6295712 DP sst bed 200 35 686381 6295277 DP ssturb bed 210 40 686701 6295432 RC ssturb bed 220 50 687650.3 6296458 RC ss bed 205 20 687658.8 6296382 CE si bed 185 30 686534.6 6294967 CE si bed 155 15 686505 6295055 CE ssturb bed 145 20 686534 6295147 CE sst bed 170 30 686345.1 6294958 CE sst bed 175 20 686405 6295141 RC si? bed 180 20 687263 6295092 RC sst bed 180 65 685995.9 6295054 RC si bed 190 15 686061 6295043 RC ssturb bed 160 35 686127 6295025 EW ssturb bed 190 20 685989 6296447 EW si bed 90 10 686003.5 6296379 EW ssturb_si_ord bedcontact? 275 10 686016 6296332 EW ssturb bed 210 50 686035 6296382 EW mss bed 225 45 685971 6296500 CE ss_siturb bedcontact 215 55 686077.3 6295282 CE si bed 85 15 686121 6295310 CE si bed 210 30 686123 6295232 CE ss_siturb bedcontact 85 30 686123 6295157 CE ss bed 155 20 686271 6295308 CE mss bed 180 25 686197 6295366 CE mss bed 185 20 686135 6295359 CE ss bed 205 20 686183 6295562 CE mss bed 190 25 686268 6295483 CE ss bed 205 35 686332 6295481 CE mss bed 180 40 686320 6295567 CE mss bed 180 25 686385 6295566 CE ss bed 190 20 686442 6295566 CE si_ssturb bedcontact 170 20 686409 6295501 CE ss bedcontact 110 15 686342 6295411 CE ss bed 185 30 686424 6295353 CE mss bed 175 35 686464 6295402 CE mss bed 175 30 686513 6295483 CE mss bed 190 25 686461 6295218 SR mss bed 45 25 686508 6296146 SR ssturb bed 75 40 686189 6296140 135 station lithology measurement strike dip Easting Northing SR ssturb_si bedcontact 50 35 686187.9 6296161 SR mss bed 75 45 686163.3 6296192 SR siturb bed 70 50 686154 6296095 SR ssturb bed 55 40 686160 6296085 SR mss bed 45 35 686194 6296060 SR ssturb bed? 95 55 686260.6 6296082 SR si_ssturb bedcontact? 80 30 686268.3 6296082 SR siturb bed 265 80 686284.4 6296030 SR mss bed 180 60 686270 6295965 SR mss bed 155 55 686270 6295944 SR si bed 50 50 686188 6296152 SW ssturb bed 140 50 685481 6295409 SW mss_siturb bedcontact 65 15 685576 6295445 SW redsi bed 145 50 685767 6295499 SW siturb bed 195 35 685730 6295463 SW ssturb bed 195 35 685721 6295460 SW ss bed 200 10 685660 6295441 SW siturb bed 180 15 685644 6295434 SW mss bed 190 30 685674 6295445 SW ssturb bed 160 90 685389 6295449 SW mss_ord bedcontact 95 15 685488 6295453 SW ss bed 195 15 685638 6295477 SW siturb bed 170 20 685686 6295494 RC ss bed 190 25 686288.6 6294911 RC ss bed 220 25 686303.5 6294905 RC ss bed 230 15 686313.5 6294901 RC ss bed 225 20 686321.8 6294896 RC siturb bed 215 15 686341.9 6294885 RC ssturb bed 220 25 686116.4 6295028 RC si bed 205 25 686106.7 6295030 RC si bed 180 15 686099 6295031 RC si bed 180 10 686080.8 6295035 RC si bed 180 15 686070.3 6295036 RC si bed 170 25 686039.2 6295044 RC si bed 170 20 686020.4 6295049 RC si bed 150 15 686005.2 6295052 RC si bed 185 20 686533.3 6294772 RC si bed 190 20 686516.7 6294783 RC ss bed 220 15 686491.9 6294795 RC si bed? 150 10 686701.2 6294693 RC si bed 160 20 686682.4 6294703 RC mss bed? 125 20 686674.1 6294706 RC si? bed 200 20 687254.5 6295061 RC si? bed 170 20 687233 6294993 RC si? bed 190 15 687243.4 6295027 RC si bed 120 30 687657.5 6296385 RC si bed 120 60 687654.6 6296397 136 station lithology measurement strike dip Easting Northing RC si bed 175 25 687650.7 6296401 RC si bed 105 30 687649.9 6296399 RC si bed 120 50 687651.5 6296398 RC si bed 185 25 687648.4 6296407 RC ss bed 165 40 687644.3 6296417 RC ss bed 150 25 687645.2 6296419 RC ss bed 190 40 687644.1 6296430 RC si bed 250 85 687644.8 6296440 RC ss bed 105 55 687647.2 6296450 CG ss bed 185 30 686316.2 6295751 CG si bed 185 25 686421.8 6295789 CG si bed 150 25 686418 6295786 CG si bed 105 35 686400.3 6295766 CG si bed 125 20 686392.2 6295760 CG si bed 150 20 686377.9 6295754 CG ss bed 205 30 686293.5 6295755 CG ss bed 200 35 686281.9 6295749 CG ss bed 190 25 686258.4 6295734 CG ss bed 65 20 686234.9 6295714 CG ss bed 205 30 686224.1 6295720 CG ss bed 125 10 686221 6295712 SW ss bed 125 50 685415.1 6295452 SW ss bed 140 55 685425.1 6295452 SW ss bed 115 45 685439.3 6295453 SW ss bed 135 30 685457.9 6295453 SW ss bed 135 35 685484.1 6295451 SW ss bed 150 25 685516 6295456 SW ss bed 150 25 685578.7 6295465 SW ss bed 150 10 685616.8 6295470 SW ss bed 310 10 685653.5 6295482 SW redsi bed 150 35 685708.2 6295503 SW redsi bed 190 30 685744 6295521 SW siturb bed 150 20 685520.9 6295426 SW ss bed 140 25 685497.4 6295417 SW ssturb bed 140 20 685540.1 6295433 SW mss bed 180 35 685564 6295440 SW ss bed 150 20 685595.3 6295450 SW siturb bed 140 20 685616.1 6295454 SW mss bed 140 15 685640 6295459 SW mss bed 155 15 685669.6 6295468 SW siturb bed 180 25 685695.5 6295475 SW siturb bed 175 30 685717.8 6295484 SW redsi bed 180 30 685754.4 6295495 DP mss bed 185 20 686382.3 6295284 DP ssturb bed 240 60 686700.4 6295421 CE si bed 290 25 686541.5 6294979 CE si bed 290 5 686546.3 6294982 137 station lithology measurement strike dip Easting Northing CE si bed 350 35 686549.7 6294985 CE si bed 175 45 686556.4 6294983 CE si bed 200 25 686560.5 6294977 CE si bed 120 35 686509.7 6295059 CE si bed 220 45 686518.5 6295056 CE ssturb bed? 10 55 686540.2 6295143 CE mss bed 215 20 686357.9 6294964 CE mss bed 150 25 686407.4 6295145 CE mss bed 200 25 686409.4 6295148 CE mss bed 195 30 686413.5 6295148 CE mss bed 210 30 686418.9 6295147 CE mss bed 180 20 686423 6295146 CE si bed 200 80 686079.6 6295280 CE si bed 235 30 686076.6 6295280 CE si bed 195 50 686075.2 6295283 CE siturb bed 205 70 686072.8 6295283 CE siturb bed 190 60 686073.2 6295285 CE ss bed 210 20 686074.2 6295288 CE ssturb bed 355 35 686077.6 6295278 CE si bed 170 25 686122.4 6295304 CE si bed 165 20 686122.7 6295296 CE si bed 165 20 686123.7 6295286 CE si bed 180 30 686127.4 6295269 CE si bed 200 30 686129.8 6295258 CE si bed 210 30 686129.8 6295249 CE si bed 155 20 686128.8 6295239 CE si bed 170 30 686123.4 6295156 CE siturb bed 205 40 686126.1 6295153 CE siturb bed 200 45 686127.8 6295151 CE siturb bed 210 60 686125.7 6295150 CE si bed 190 45 686122.7 6295160 CE si bed 195 40 686125.7 6295162 CE mss bed 155 30 686200.6 6295366 CE mss bed 165 40 686203.6 6295363 CE mss bed 185 20 686137.9 6295353 CE mss bed 185 25 686131.5 6295362 CE mss bed 175 20 686129.1 6295363 CE mss bed 185 30 686136.6 6295356 CE mss bed 185 45 686127.6 6295363 CE mss bed 200 20 686120.7 6295362 CE ss bed 210 30 686180.6 6295566 CE ss bed 200 10 686186.7 6295557 CE mss bed 185 25 686264.6 6295464 CE mss bed 170 30 686266.6 6295475 CE mss bed 185 25 686269.4 6295493 CE mss bed 185 30 686273.1 6295504 CE ss bed 195 25 686447.5 6295571 138 station lithology measurement strike dip Easting Northing CE ss bed 200 15 686453 6295578 CE ss bed 200 25 686438.7 6295559 CE si bed 155 25 686409.4 6295506 CE ss bed 140 30 686408.7 6295496 CE si bedcontact 90 15 686341.3 6295415 SR ss bed 55 45 686186.7 6296166 SR ss bed 60 45 686182.3 6296168 SR ssturb? bed 85 40 686154.5 6296093 SR siturb bed 40 40 686155.9 6296090 SR siturb bed 50 45 686157.3 6296089 SR ssturb bed 50 40 686163.1 6296081 SR ssturb bed 35 40 686200.8 6296059 SR ssturb bed? 175 45 686256.1 6296081 SR si bed? 145 30 686270.3 6296077 SR siturb bed 255 85 686288.6 6296030 SR si bed 235 45 686289.9 6296029 SR si bed 65 45 686292 6296023 SR ssturb bed 60 65 686292.8 6296019 SR ssturb bed 65 50 686293.3 6296015 SR ssturb bed 70 45 686293.5 6296012 SR mss bed 185 65 686270 6295958 SR mss bed 195 80 686269.6 6295954 SR mss bed 190 75 686269.4 6295949 SR mss bed 170 50 686269.6 6295947 SW ssturb bed 190 30 685716.8 6295459 SW ssturb bed 190 25 685709.3 6295455 SW ssturb bed 200 30 685705.3 6295453 EW ssturb bed 95 10 686039.3 6296364 EW ssturb bed 275 5 686043 6296344 EW mss bed 215 45 685969.6 6296498 EW mss bed 210 40 685967.1 6296494 EW mss bed 110 75 686023.5 6296136 EW mss bed 90 50 686023.1 6296139 EW ssturb? bed 230 15 685978.1 6296399 EW ssturb? bed 150 25 685971.4 6296417 EW ssturb? bed 205 15 685968.6 6296422 EW ssturb? bed 225 15 685966.6 6296427 EW mss bed 230 45 685956.4 6296450 EW mss bed 175 20 685944.3 6296482 EW mss bed 200 30 685939.9 6296496 EW ssturb bed 210 20 685988.6 6296441 EW ssturb bed 140 20 685988.6 6296437 EW ssturb bed 210 5 685990 6296426 EW si bed 165 15 685993.7 6296411 EW si bed 190 5 685999.5 6296396 EW si bed 300 5 686000.8 6296385 EW si bed 240 5 686008.3 6296365 139 station lithology measurement strike dip Easting Northing EW si bed 230 25 686013 6296350 RC ss bed 210 45 686119.8 6295022 RC ss bed 180 45 686123 6295021 RC ss bed 160 35 686125.9 6295023 RC ss bed 190 38 686117.9 6295026 RC ss bed 220 22 686114.7 6295030 RC si bed 170 35 686112.8 6295025 RC si bed 205 15 686110.5 6295028 RC si bed 205 23 686106.3 6295029 RC si bed 180 15 686098.3 6295030 RC si bed 202 55 686094.5 6295031 RC si bed 190 12 686085.8 6295031 RC si bed 175 15 686085.8 6295033 RC si bed 180 10 686083.5 6295036 RC si bed 185 30 686075.7 6295036 RC si bed 180 15 686073.4 6295031 RC si bed 180 15 686070.8 6295035 RC si bed 190 15 686061.8 6295038 RC si bed 160 20 686052.9 6295040 RC si bed 180 20 686038.1 6295044 RC si bed 165 20 686045.5 6295042 RC si bed 185 15 686044.7 6295042 RC si bed 170 25 686043.2 6295042 RC si bed 165 25 686049.5 6295037 RC si bed 175 40 686030.7 6295045 RC si bed 170 30 686028 6295046 RC si bed 170 20 686020.6 6295048 RC si bed 170 25 686016.8 6295049 RC si bed 220 15 686013.2 6295050 RC si bed 193 35 686011.3 6295050 RC si bed 155 15 686009 6295051 RC si bed 150 15 686006.9 6295051 RC si bed 170 40 686000.6 6295053 RC si bed 180 55 685998 6295053 RC ss bed 180 20 687262.9 6295091 RC ss bed 200 20 687255.7 6295056 RC ss bed 190 20 687252.8 6295047 RC ss bed 180 20 687249.6 6295036 RC ss bed 190 15 687241.8 6295015 RC ss bed 170 20 687230.8 6294981 RC siturb bed 210 40 686285.2 6294913 RC ss bed 190 25 686287.8 6294912 RC ss bed 195 35 686292.6 6294911 RC ss bed 200 20 686295.1 6294911 RC ss bed 180 15 686299 6294911 RC ss bed 235 20 686299.7 6294907 RC ss bed 285 25 686301.6 6294906 140 station lithology measurement strike dip Easting Northing RC ss bed 220 25 686304.2 6294907 RC ss bed 25 60 686305.3 6294904 RC ss bed 225 15 686307.6 6294903 RC ss bed 80 15 686310.2 6294904 RC ss bed 230 15 686312.5 6294903 RC ss bed 175 30 686316.2 6294904 RC ss bed 235 35 686318.2 6294901 RC ss bed 165 15 686322.5 6294905 RC ss bed 225 20 686322.5 6294898 RC ss bed 230 15 686333.6 6294896 RC siturb bed 235 15 686335.1 6294892 RC siturb bed 205 5 686336.6 6294887 RC siturb bed 215 15 686341.3 6294886 RC siturb bed 210 15 686351.1 6294882 RC siturb bed 240 15 686356.5 6294879 RC siturb bed 230 20 686360.6 6294878 RC siturb bed 240 30 686365.1 6294872 RC ssturb bed 215 20 686500.7 6294791 RC si bed 165 10 686550.2 6294763 RC si bed 190 20 686547.2 6294764 RC si bed 170 10 686543.5 6294767 RC si bed 185 20 686533.7 6294769 RC si bed 175 75 686530.8 6294768 RC si bed 205 15 686530.1 6294772 RC si bed 195 5 686523.9 6294777 RC si bed 190 20 686517.6 6294783 RC ssturb bed 205 15 686504.2 6294791 RC ssturb bed 35 5 686499.6 6294791 RC ssturb bed 220 15 686497.6 6294794 RC ss bed 220 15 686488 6294799 RC ss bed 215 20 686480.8 6294802 RC si bed 110 10 686716.2 6294686 RC ss bed 125 20 686677.5 6294704 RC si bed 150 10 686702 6294692 RC si bed? 60 15 686700.4 6294693 RC si bed? 270 50 686700.3 6294693 RC si bed 160 20 686682.6 6294702 RC ss bed 110 15 686667.8 6294709 RC ss bed 125 25 686659 6294713 RC ss bed 100 25 686653.4 6294716 RC ss bed? 210 15 686649.9 6294718 RC ss bed? 280 40 686650.2 6294718 RC mss bed 205 20 687659 6296383 RC siturb bed 250 85 687646.4 6296443 RC ssturb bed 220 50 687653.4 6296459 RC ssturb bed 215 55 687650.4 6296457 RC ssturb bed 200 35 687648.9 6296455 141 station lithology measurement strike dip Easting Northing RC ssturb bed 170 30 687648.7 6296454 RC ssturb bed 140 40 687648.4 6296454 RC ssturb bed 170 30 687648.9 6296452 RC ssturb bed 145 30 687648.7 6296451 RC ssturb bed 105 55 687648.2 6296450 RC ssturb bed 160 30 687649.4 6296448 RC ssturb bed 110 40 687647.2 6296447 RC ssturb bed 100 60 687646.9 6296445 RC ssturb bed 135 40 687643.4 6296438 RC ssturb bed 195 45 687647.1 6296436 RC ssturb bed 190 30 687644.6 6296436 RC ssturb bed 210 45 687643.9 6296433 RC ssturb bed 140 30 687645.9 6296432 RC ssturb bed 190 30 687642.1 6296430 RC mss bed 190 40 687646.4 6296428 RC siturb bed 180 25 687647.6 6296407 RC mss bed 190 50 687645.1 6296426 RC mss bed 145 40 687644.9 6296424 RC mss bed 195 25 687644.9 6296423 RC mss bed 150 25 687645.7 6296420 RC mss bed 120 80 687647.6 6296419 RC mss bed 165 40 687645.7 6296418 RC mss bed 170 30 687645.9 6296416 RC siturb bed 185 25 687646.2 6296405 RC siturb bed 175 25 687651.4 6296401 RC siturb bed 105 30 687649.9 6296399 RC siturb bed 195 25 687650.7 6296399 RC siturb bed 120 55 687650.4 6296398 RC siturb bed 135 25 687651.1 6296398 RC siturb bed 120 50 687651.5 6296398 RC siturb bed 95 90 687651.4 6296397 RC siturb bed 100 75 687654.4 6296397 RC siturb bed 230 15 687653.7 6296395 RC siturb bed 120 60 687656.2 6296396 RC siturb bed 115 25 687654.6 6296393 RC siturb bed 120 40 687656.1 6296388 RC siturb bed 125 40 687655.5 6296387 RC siturb bed 120 30 687657.2 6296386 RC siturb bed 130 10 687657.5 6296384 CG si bed 290 45 686470.3 6295861 CG ss bed 205 45 686343.8 6295749 CG si bed 240 45 686462.7 6295856 CG si bed? 65 45 686444.5 6295852 CG si bed 145 10 686439 6295847 CG si bed 80 20 686420 6295800 CG si bed 185 25 686419.7 6295791 CG si bed 150 25 686419.2 6295788 142 station lithology measurement strike dip Easting Northing CG si bed 115 10 686417 6295784 CG si bed 105 35 686395.8 6295766 CG si bed 125 20 686389.3 6295761 CG si bed 150 20 686377.8 6295755 CG si bed 155 20 686370.2 6295754 CG ss bed 205 35 686343 6295752 CG ss bed 210 45 686343 6295754 CG ss bed 210 35 686322.1 6295750 CG ss bed 185 30 686313.7 6295756 CG ss bed 220 35 686297.4 6295759 CG ss bed 205 35 686293.3 6295758 CG ss bed 195 30 686286.8 6295754 CG ss bed 200 35 686280.8 6295751 CG ss bed 185 25 686264.2 6295744 CG ss bed 205 25 686261.5 6295743 CG ss bed 190 20 686260.1 6295742 CG ss bed 190 25 686258.2 6295741 CG ss bed 65 20 686236.7 6295720 CG ss bed 205 30 686222.3 6295720 CG ss bed 125 10 686221.2 6295713 CG ss bed 180 20 686214.2 6295712 EW ss bed 110 75 686024.6 6296135 EW ss bed 90 50 686024.4 6296139 EW ss bed 90 60 686017.6 6296152 EW ss bed 90 55 686017.6 6296157 EW ss_ord bedcontact 90 75 686017.8 6296159 EW ssturb bed? 300 15 685996.6 6296357 EW ssturb bed 310 10 685988.2 6296388 EW ssturb bed 225 5 685984.9 6296400 EW ssturb bed 230 15 685982.8 6296404 EW ssturb bed 335 15 685982.5 6296405 EW ssturb bed 150 25 685974.6 6296418 EW ssturb bed 205 15 685969.7 6296424 EW ssturb bed 225 15 685972.7 6296428 EW ssturb bed 185 15 685967.8 6296428 EW mss bed 220 25 685966.4 6296432 EW mss bed 195 25 685963.2 6296441 EW mss bed 155 30 685961.3 6296444 EW mss bed 215 35 685963.5 6296449 EW mss bed 230 45 685963.7 6296455 EW mss bed 175 20 685948.8 6296484 EW mss bed 200 30 685945.8 6296489 EW mss bed 215 40 685943.9 6296493 EW mss bed 200 30 685941.7 6296496 EW ssturb bed 115 40 685990.1 6296452 EW ssturb bed 190 20 685993.1 6296444 EW ssturb bed 210 20 685994.5 6296440 143 station lithology measurement strike dip Easting Northing EW ssturb bed 140 20 685993.1 6296436 EW ssturb bed 205 50 685992.8 6296432 EW ssturb bed 210 5 685993.9 6296427 EW siturb bed 215 10 685992 6296420 EW siturb bed 55 15 685995.5 6296416 EW siturb bed 165 15 685996.1 6296412 EW siturb bed 215 25 685997.7 6296408 EW siturb bed 195 10 685998.8 6296405 EW siturb bed 175 10 685999.6 6296398 EW siturb bed 190 5 686000.7 6296393 EW siturb bed 260 2 686001.3 6296389 EW siturb bed 300 5 686003.4 6296382 EW siturb bed 90 10 686003.4 6296378 EW siturb bed 255 35 686006.4 6296372 EW siturb bed 270 10 686008.1 6296368 EW siturb bed 240 5 686009.8 6296362 EW siturb bed 50 15 686010.2 6296361 EW siturb bed 230 25 686012 6296355 EW siturb bed 230 25 686013.1 6296351 EW siturb bed 290 20 686015.3 6296347 EW ssturb bed 275 10 686023.3 6296337 SW siturb bed 150 10 685513 6295423 SW ss bed 140 50 685482 6295407 SW ss bed 160 55 685488.1 6295409 SW ss bed 120 65 685489 6295410 SW ssturb bed 160 30 685493.5 6295414 SW ssturb bed 140 25 685497.2 6295416 SW ssturb bed 145 20 685505.2 6295420 SW siturb bed 150 20 685520.1 6295425 SW siturb bed 155 20 685525 6295427 SW siturb bed 155 20 685530.4 6295429 SW ss bed 170 30 685533.8 6295430 SW ss bed 140 20 685542.9 6295433 SW siturb bed 140 20 685548.4 6295435 SW siturb bed 140 20 685555 6295435 SW ss bed 180 35 685565 6295437 SW ss bed 200 50 685570.6 6295440 SW mss bed 65 15 685572.2 6295443 SW ssturb bed 150 30 685575.2 6295445 SW ssturb bed 130 50 685577.5 6295445 SW ssturb bed 115 25 685588.7 6295447 SW mss bed 150 20 685598.5 6295445 SW ssturb bed 135 25 685605.2 6295450 SW siturb bed 115 30 685609.6 6295452 SW siturb bed 140 20 685615.9 6295453 SW siturb bed 145 25 685624.4 6295455 SW mss bed 140 15 685635.8 6295457 144 station lithology measurement strike dip Easting Northing SW mss bed 130 15 685649.6 6295459 SW mss bed 140 10 685661.4 6295463 SW mss bed 155 15 685669.4 6295464 SW mss bed 190 10 685673.4 6295467 SW mss bed 160 15 685680 6295469 SW siturb bed 175 20 685691.4 6295474 SW mss bed 180 25 685702.8 6295478 SW ssturb bed 190 25 685711.6 6295481 SW siturb bed 175 30 685716.6 6295483 SW siturb bed 175 35 685730.8 6295488 SW redsi bed 180 30 685752.3 6295494 SW redsi bed 155 35 685760.8 6295496 SW redsi bed 145 50 685771.5 6295498 SW redsi bed 160 35 685729.1 6295512 SW si bed 160 90 685392.5 6295449 SW si bed 150 90 685394 6295449 SW si bed 150 90 685395.4 6295449 SW mss bedcontact 125 50 685414.2 6295450 SW mss bedcontact 130 60 685416.3 6295450 SW si bed 140 80 685418.2 6295451 SW si bed 140 55 685423.8 6295451 SW mss bed 150 50 685436.6 6295451 SW mss_turb bedfault 115 45 685439.8 6295450 SW mss bed 135 35 685447.7 6295451 SW mss bed 135 40 685452.3 6295451 SW siturb bed 135 30 685460.8 6295451 SW siturb bed 140 25 685469.2 6295451 SW siturb bed 140 35 685475.1 6295451 SW siturb bed 135 30 685481 6295451 SW mss_ord bedcontact 135 35 685484.4 6295451 SW mss_ord bedcontact 95 15 685490 6295451 SW mss_ord bedcontact 190 5 685497 6295451 SW mss_ord bedcontact 355 10 685502.4 6295451 SW mss_ord bedcontact 150 25 685518.4 6295452 SW mss_ord bedcontact 20 40 685573.6 6295462 SW ssturb bed 150 25 685580.1 6295464 SW ssturb bed 140 10 685588.7 6295465 SW ssturb bed 150 10 685615.8 6295469 SW ssturb bed 195 15 685633.6 6295475 SW ssturb bed 310 10 685652.1 6295481 SW ssturb bed 180 5 685667.1 6295486 SW ssturb bed 220 25 685671.7 6295488 SW siturb bed 170 20 685685.6 6295493 SW siturb bed 175 35 685696.7 6295499 SW si bed 155 35 685706.2 6295503 SW si bed 155 35 685710.6 6295505 SW si bed 150 35 685708.6 6295504 145 station lithology measurement strike dip Easting Northing SW redsi bed 170 30 685724.3 6295510 SW redsi bed 155 40 685730.6 6295513 SW redsi bed 90 30 685745.9 6295519 SW redsi bed 230 40 685756 6295524 SW redsi bed 145 40 685760.8 6295526 SW redsi_ord bedcontact 165 20 685761.6 6295527 RC si bed 210 40 686285 6294913   146 Appendix II: Fault Measurements   The following data table represents a compilation of measurements gathered over both the 2006 and 2007 field season.  Measurements (in degrees) and corresponding coordinates (given as Easting and Northing) are in Australia Map Grid projection, using the datum AGD66.  Strike and dip was measured with a Brunton compass, and measurements were rounded in the field to the nearest 5o.  Strike measurements were always taken so that the plane being measured dipped to the right (for example, N- striking planes dip to the E).  Where measurement or lithology was uncertain, it is indicated with a question mark. The “station” column indicates a general geographic area for measurement location.  CE=Cadia East, CG=Copper Gully, RC=roadcutting from the Cadia Hill access road, SR=Sharps Ridge, SW=southern wall of Cadia Hill pit, EW=eastern wall of Cadia Hill pit, DP=drill pad (Cadia East or Sharps Ridge). The “lithology” column indicates what rock type bedding was measured in.  Units on either side of the fault are separated with an underscore, and the upper unit is listed first.  Abbreviations are as follows: si=siltstone, ss=sandstone (undifferentiated), siturb=siltstone-dominant interbedded siltstone and sandstone, ssturb=sandstone- dominant interbedded siltstone and sandstone, mss=massive sandstone, redsi=red siltstone, blksi=black shale, bc=boulder conglomerate, sibx=brecciated siltstone, ord=Ordovician basement (undifferentiated), ark=arkose. The “measurement” column indicates what feature was measured at each location. Abbreviations used are: fault_bed=bedding parallel fault, fault_contact=faulted contact within the cover rocks (i.e. juxtaposing different stratigraphic units), fault_unconf=fault at the unconformity between the basement and cover rocks.  The “sense” column indicates the general sense of separation on the measured fault observed in the field. Normal separation is indicated by “N”, reverse separation by “R”.  Although faults fitting in either of these categories may have experienced motion in the third dimension, faults which appear to display a strong strike-slip component are indicated by “X”.  Faults measured in the Ordovician basement rocks were mostly undifferentiated in the field, due to poor stratigraphic control, and are marked with “U”. 147 The “class” column shows information about the estimated magnitude of displacement along the measured fault, with 1 being the most and 3 being the least.  In general, quantifying displacement was not possible due to lack of marker horizons and the prevalence of faults at a low angle to bedding, but a qualitative assessment based on the estimated width and infill (if any) of the damage zone, juxtaposition of stratigraphic units, and other related disruption (e.g. folds) was attempted.  Displacement on class 3 faults was estimated to be on the mm-cm scale.  Displacement on class 1 faults was estimated to exceed 20m, while class 2 faults were categorized as having experienced displacement on the meter scale.  While this classification is somewhat arbitrary, it allows for division of recognized faults into groups which accommodated relatively major (10s of meters) vs. minor (less than 1 m) amounts of shortening.  Faults in the Ordovician basement were not classified, and were assigned a class of 0.                    148 station lithology measurement sense class strike dip Easting Northing EW ord fault_unconf U 0 95 75 686031 6296106 EW ord fault U 0 105 50 686014 6296212 EW ord fault U 0 110 50 686006 6296254 CE mss fault N 2 90 90 686133 6295359 SR si fault N 2 25 90 686290.9 6296025.9 SR mss fault N 3? 75 80 686269.8 6295962.3 EW ss fault N 2? 50 60 686014 6296360.6 EW si fault N 2 75 75 685990.3 6296443.3 RC si? fault N? 3 180 85 687207 6294924 SW mss fault R 2 165 65 685708 6295453 SW ss_si fault_contact R 2? 180 25 685690 6295449 SW si fault_unconf R 1? 165 20 685764 6295535 CE si fault_contact R 1? 195 55 686559.1 6294986.7 CE si fault R 2 120 45 686517.1 6295059.9 CE si fault R 2 135 40 686513.1 6295057.2 CE ss_siturb fault N 2 180 55 686078.9 6295278.5 CE ss_siturb fault_contact R 1 200 30 686073.9 6295286.3 CE si fault N 2 205 50 686122.7 6295157.8 CE ss fault R 2? 155 45 686343 6295408.4 SW ssturb fault R 2 175 70 685719.5 6295458.9 CE si fault N 2? 250 90 686545.6 6294977.2 CE si fault N 3 250 90 686550.3 6294979.9 CE ss_siturb fault R 3 220 90 686077.3 6295282.1 CE si fault R 3 290 90 686123.7 6295153.4 CE mss fault N 2 275 90 686126.7 6295365.4 SR si fault R? 1 265 90 686286.5 6296030.4 EW mss fault N 2? 230 85 685964.4 6296430 EW mss fault R 2? 230 50 685964.6 6296429 EW ss_si fault R 2 280 45 686019.5 6296340.3 EW si fault R 2 270 60 686002.2 6296390.8 EW ssf fault R? 1 80 80 686035 6296382 SR ss? fault R? 3 15 60 686177 6296104 SW mss fault R 2 165 65 685708 6295453 CG mss fault R? 3 120 55 687434 6296525 CG mss fault R? 2? 145 40 687430 6296520 CG mss fault R 2? 170 60 687416 6296515 CG mss fault R? 2? 80 65 687344 6296319 CG si fault_contact R 2? 85 70 687326 6296293 CG mss_ssturb fault_contact X 1 220 90 686254.1 6295797.1 CG ord? fault U 0 170 55 686117 6295953 CG mss_ssturb fault_contact X 1 225 85 686249.8 6295798.9 CG ss fault_contact R 2? 290 45 687307.4 6296300 RC ss_si fault_contact R 1 160 50 686113.7 6295027.6 RC ss fault N 3 220 70 686118.7 6295025.9 RC ss fault X 2 217 75 686120 6295025.7 RC si fault N? 3? 170 45 686073.6 6295029.3 RC si fault N 3 235 70 686071.3 6295035.2 149 station lithology measurement sense class strike dip Easting Northing RC si fault N 3 260 90 686071.7 6295035 RC si fault R 2? 170 40 686067.5 6295036.5 RC si fault R 1 170 40 686078.4 6295033.3 RC si fault R 3 185 45 686095.1 6295023.6 RC si fault X 2 265 90 686086.2 6295031.2 RC si fault R 3 180 65 686097 6295029.9 RC si fault N 3 245 85 686107.8 6295027.6 RC si fault_contact R 1 165 60 685994.9 6295053.3 RC si fault N? 3 155 40 686008.6 6295049.3 RC si fault R? 2 150 45 686018.5 6295046.6 RC si fault N 3 250 90 686031 6295045.5 RC si fault N 3 220 90 686039.6 6295043.2 RC si fault N 2 90 50 686043.6 6295042.2 RC si fault N 3 75 60 686047.2 6295041.5 RC si fault N 2 255 90 686048.5 6295040.9 RC si fault N 3 160 90 686047.6 6295039 RC si fault N 3 280 90 686051.9 6295036.5 RC ss fault N 3 80 90 687263.1 6295087.9 RC ss fault N 3 250 80 687261.4 6295077 RC ss fault N 3 150 35 687258.2 6295060.5 RC ss fault N 3 250 80 687253.4 6295053.1 RC ss fault N 3 50 90 687250.9 6295040 RC ss fault N 3 180 90 687251.1 6295045.1 RC siturb_ss fault_contact R 1 165 40 686287.6 6294913 RC ss fault N 2 70 90 686297 6294908.6 RC ss fault R 2 235 35 686304.9 6294904.3 RC ss fault R 3? 255 30 686313.7 6294908.3 RC ss fault R 2 240 65 686310.5 6294905.3 RC ss fault R 2 230 45 686313.5 6294903.8 RC ss fault R 2 280 40 686319.7 6294901 RC ss_siturb fault_contact X 1 85 90 686330.8 6294891.4 RC siturb fault R 1 255 50 686334.2 6294893.2 RC siturb fault R 1 250 35 686330.2 6294893.5 RC siturb fault N 3 70 90 686334.2 6294889.2 RC siturb fault R 3 85 85 686337.7 6294889.8 RC siturb fault R 3 260 85 686338.5 6294888.8 RC siturb fault N 3 75 90 686341.8 6294884.9 RC siturb fault N 3 355 55 686346.3 6294884.5 RC si fault N 3 5 55 686356.2 6294875.7 RC si fault_contact R 2? 250 40 686365.9 6294882.3 RC si fault N 3 65 90 686360.6 6294875.5 RC si fault R 3 25 45 686363.4 6294875.1 RC si fault R? 3? 185 20 686368.2 6294871 RC si fault R? 2? 180 50 686546.5 6294764.2 RC si fault N 3 220 90 686542.3 6294766.5 RC si fault N 3 195 90 686538.6 6294768.1 RC si fault N 3 235 90 686531.4 6294772.1 150 station lithology measurement sense class strike dip Easting Northing RC si fault N 3 175 90 686528.5 6294775.9 RC si fault R 3 20 30 686526.5 6294776.7 RC si fault R 3 20 30 686525.2 6294777.9 RC si fault N 2 20 40 686519 6294778.9 RC si fault R 2? 195 20 686514.9 6294782.9 RC si fault N 2 30 40 686512.4 6294784.1 RC si fault R 2 160 85 686511.9 6294786.7 RC si fault N 3 50 60 686510.8 6294787.1 RC ss fault R 3 205 70 686500.4 6294789.4 RC ss fault R 3 225 90 686501.1 6294792.6 RC ss fault R 3 230 90 686498.6 6294792 RC ss fault R 2 215 20 686480.8 6294798.5 RC si fault N 3 155 90 686702.1 6294690.6 RC si fault N 3 300 60 686700.7 6294692.2 RC si fault N 3 170 90 686699.1 6294692.2 RC si fault R? 2 40 45 686694.7 6294695.6 RC si fault N? 3 230 90 686693.8 6294696.8 RC si_ss fault_contact R 2 200 45 686681.3 6294700.8 RC si_ss fault_contact R 2 250 30 686678.8 6294704.3 RC ss fault N 3 240 90 686673.2 6294705.5 RC ss fault N 3 240 90 686664.7 6294710 RC ss fault R 2 235 50 686661.7 6294711.7 RC ss fault N 3 195 70 686655.7 6294714.8 RC ssturb fault R 3 60 70 687648.2 6296451.4 RC ssturb fault R 3 250 70 687648 6296449.6 RC ssturb fault R 2 65 80 687648.7 6296447.8 RC ssturb fault_contact R 2 250 85 687644.1 6296438.9 RC ssturb fault R 3 90 75 687643.9 6296434.6 RC mss fault R 2 275 80 687643.4 6296430 RC mss fault N 2 270 50 687643.4 6296427.8 RC mss fault R 3 130 30 687644.6 6296422.6 RC mss fault R? 2 85 85 687646.5 6296417 RC mss fault R? 1 165 45 687645.7 6296415 RC siturb fault N? 3 10 90 687649.5 6296403.8 RC siturb fault R? 3 35 80 687650.5 6296403.4 RC siturb fault R 1? 275 75 687648.7 6296402.6 RC siturb fault R? 1? 190 30 687650.7 6296402.1 RC siturb fault R? 3 270 55 687652.6 6296400.6 RC siturb fault N 2 100 90 687652.5 6296397.4 RC siturb fault N 2 95 90 687654.6 6296394.4 RC siturb fault R 2 240 10 687655.4 6296392.4 RC siturb_ss fault_contact R 1 65 90 687658.7 6296383.7 EW ord fault_unconf R 1 95 75 686030.3 6296111.4 EW mss fault R? 1 315 75 686029 6296117.9 EW mss fault_contact R 2? 10 50 686025.7 6296132 EW mss fault_contact R 2? 115 75 686025.7 6296136.9 EW mss fault R 2? 105 45 686021.9 6296146.2 151 station lithology measurement sense class strike dip Easting Northing EW mss fault_contact R 2 80 60 686019.5 6296155.1 EW mss_ord fault_unconf R 1 90 75 686019.2 6296160.6 EW ord fault U 0 105 50 686017 6296211.7 EW ord fault U 0 95 35 686011 6296216.9 EW ord fault U 0 90 75 686010 6296219 EW ord fault U 0 130 70 686009.1 6296226.9 EW ord fault U 0 285 75 686011.6 6296234.3 EW ord fault U 0 5 80 686012.4 6296242.7 EW ord fault U 0 65 60 686008 6296253.6 EW ord fault U 0 110 50 686008.3 6296256.8 EW ord fault U 0 270 80 686011.6 6296274.2 EW ord fault U 0 80 90 686012.4 6296276.4 EW ord fault U 0 85 90 686012.7 6296280.5 EW ord fault U 0 110 55 686015.4 6296281.3 EW ord fault U 0 65 35 685998.3 6296338.9 EW ord fault U 0 285 30 686009.1 6296310.4 EW ord fault U 0 65 40 686006.4 6296318.8 EW ord fault U 0 355 50 686002.6 6296329.2 EW ord fault U 0 265 35 686013.8 6296299.5 EW ord fault U 0 355 35 685992.5 6296355.5 EW ord fault U 0 125 60 685992.3 6296363.7 EW ord fault U 0 110 20 685989.3 6296374.3 EW ord fault U 0 160 5 685975.1 6296411.8 EW mss_turb fault_contact R 1 230 50 685967.8 6296429.2 EW mss_turb fault_contact R 1 225 40 685965.6 6296430 EW mss_turb fault N 2? 230 85 685968.1 6296431.4 EW mss_turb fault_contact R? 1 215 25 685963.7 6296431.4 EW mss_turb fault R 1 210 65 685964.3 6296438.2 EW si_ord fault N 3 90 90 686020.1 6296336.7 EW si_ss fault R 2 280 45 686020.4 6296338.9 EW si_ord fault_unconf R 1 290 35 686014.2 6296346.9 EW si fault R 3 50 60 686011.6 6296360 EW si fault R 3 20 75 686008.1 6296370.4 EW si fault R 2 270 50 686001 6296390.6 EW ss fault_contact R 2 75 75 685992.1 6296439.3 SW si fault R 2 170 35 685751.3 6295493.4 SW redsi_turb fault_contact R 1 240 90 685745.4 6295492 SW siturb fault N? 3 145 60 685718.2 6295483.4 SW siturb fault N? 3 210 75 685696 6295475.1 SW ss fault N? 3 185 65 685597.3 6295449.2 SW ss fault N 3 200 70 685589.9 6295447.6 SW ss fault N 3 170 90 685578.5 6295442.8 SW ss fault N? 3 150 85 685542.3 6295431.7 SW siturb fault R 2 345 45 685557.6 6295437.1 SW siturb fault R 2 320 40 685558.4 6295437.9 SW ss fault N? 2 20 45 685567.9 6295440.9 SW siturb_ss fault N? 2 340 40 685517.2 6295423.6 152 station lithology measurement sense class strike dip Easting Northing SW ssturb fault R 2 345 35 685507 6295419.1 SW ssturb fault R 2 140 45 685497.8 6295413 SW ssturb fault R? 1 330 80 685494.6 6295412.3 SW ssturb fault R 1 140 70 685485.4 6295408.8 SW ssturb fault R 1 160 45 685483 6295407.7 SW ssturb fault N 3 345 70 685484.6 6295407.9 SW si fault R 1 145 90 685393.2 6295449.1 SW mss_turb fault_contact R 2 115 45 685439.8 6295450.3 SW si fault N 3 325 50 685394.8 6295448.9 SW si fault_contact R 1 140 90 685397.7 6295449.4 SW si_mss fault_contact R 1 140 90 685411.5 6295450 SW si_mss fault_contact R 2 125 75 685424.6 6295450.8 SW ss_mss fault_contact R 2 65 30 685434 6295450.8 SW ssturb fault N 3 210 85 685483.2 6295451.1 SW ssturb fault R 2 75 20 685483.7 6295445.7 SW ss fault N 3 195 80 685571.5 6295461.7 SW ss fault N 3 185 70 685585.5 6295464.2 SW ss fault R 2 205 80 685641.6 6295477.8 SW ss fault R 2 200 90 685665.9 6295485.8 SW ss fault R 2 230 80 685670.3 6295487.1 SW si_cong fault_contact R 2 190 90 685695.5 6295497.7 SW si_cong fault_contact R 2 170 45 685697.4 6295495.8 SW si fault N 2 200 45 685707.2 6295502.5 SW si fault R? 3 50 15 685725.3 6295509.2 SW si fault N 2 220 90 685729.2 6295510 SW si fault N? 2 210 90 685758.6 6295525.1 CE siturb_si fault X 3 215 80 686734 6294815 CE ss_siturb fault N 3 60 60 685819 6295246 CG ss fault? R? 2? 205 90 687569 6296732 CG ss fault R 1 100 80 687562 6296712 CG ss fault_bed R 2? 40 85 687557 6296666 CG SKARN fault U 0 285 80 687292 6296205 CE ss fault? R 1 190 50 686526 6295309 CG bc_sibx fault? R? 1 135 85 686815 6295945 CG bc fault? R 1 130 85 686811 6295948 CG bc?bx? fault? R? 1? 255 65 686715 6295908 CG bc? fault? R? 2? 175 85 686455 6295852 CG ord fault U 0 1 85 686454 6295838 CG ord fault U 0 225 65 686433 6295826 CG si fault R? 2? 10 90 686399 6295783 CG siturb fault R 2 150 80 686307 6295725 CG ssturb fault? R? 1 220 85 686241 6295796 CG sibx fault? R? 1? 180 85 686708 6296072 CG sibx? fault R? 1? 5 60 686730 6296100 RC si fault_bed R 2 185 70 686600 6294751 RC ssturb fault? R 2 15 45 686508 6294779 RC si fault R 2 250 45 686511 6294808 153 station lithology measurement sense class strike dip Easting Northing RC si?turb? fault R 1 220 70 686424 6294872 RC si?turb? fault? R 2? 95 85 686435 6294878 SR si fault R 2? 265 80 686291 6296016 SR ss? fault? R? 2? 20 90 686094 6296090 SR ord fault U 0 275 60 686090 6296078 SR si fault R 1 30 90 686253 6295798 SR ss fault_bed R 1 40 90 686256 6295803 SR bc fault R 1 45 90 686212 6295907 SR ss fault R 2? 40 80 686109 6296333 SR si fault R 1? 260 70 686193 6296156 CG ss fault? R? 2? 95 80 687599 6296612 CG ss fault? R 2? 80 85 687563 6296651 CG ss fault? R 2? 40 65 687563 6296662 CG ss fault? R 2? 50 80 687570 6296704 CG ssbx fault R 1? 10 65 687574 6296713 CG siturb? fault_bed? R 1? 325 75 687689 6296667 CG ssturb? fault? R 1 195 75 687739 6296772 RC si fault R 2 35 60 687673 6296494 RC si fault R 2 30 90 687673 6296486 RC ss? fault R 2 100 50 687638 6296445 RC ss? fault R 2 80 75 687639 6296445 EW ssturb fault R 1 205 60 685939 6296606 EW mss fault_bed R 1 175 30 685866 6296587 WW ord fault U 0 170 75 684760 6295938 WW ord fault U 0 140 40 684730 6295968 WW ord fault U 0 110 70 684750 6295971 WW ord fault U 0 330 40 684763 6296016 WW ord fault U 0 140 55 684762 6296011 WW ord fault U 0 175 80 684771 6296051 WW ord fault U 0 115 80 684760 6296137 WW ord fault U 0 140 75 684764 6296145 WW ord fault U 0 340 40 684764 6296153 WW ord fault U 0 165 75 684763 6296160 WW ord fault U 0 140 65 684737 6296203 WW ord fault U 0 340 60 684746 6296227 WW ord fault U 0 350 85 684748 6296234 WW ord fault U 0 80 55 684756 6296257 WW ord fault U 0 350 50 684764 6296277 WW ord fault U 0 170 70 684765 6296295 WW ord fault U 0 100 60 684799 6296393 WW ord fault U 0 110 65 684808 6296409 WW ord fault U 0 355 50 684827 6296443 EW si_ord fault_unconf R 1 90 65 685983 6296103 EW si fault R 1 110 70 686024 6296148 EW sibx fault R 1 75 35 686030 6296149 EW si fault_bed R 2? 80 65 686034 6296154 EW si fault R 1 110 85 686023 6296164 154 station lithology measurement sense class strike dip Easting Northing EW ord fault U 0 95 80 686032 6296160 EW ord fault U 0 100 75 686023 6296174 EW ord fault U 0 95 90 686024 6296170 EW ord fault U 0 115 90 686018 6296191 EW ord fault U 0 95 35 686017 6296197 EW ord fault U 0 170 80 686014 6296227 EW ord fault U 0 100 50 686014 6296228 EW ss_ssturb fault_contact R 1 180 70 685972 6296426 WW ord fault U 0 145 50 684835 6296464 WW ord fault U 0 195 65 684827 6296466 WW ord fault U 0 15 80 684843 6296483 WW ord fault U 0 90 50 684871 6296513 WW ord fault U 0 55 40 684878 6296521 WW ord fault U 0 160 75 684891 6296538 WW ord fault U 0 175 70 684891 6296536 WW ord fault U 0 165 80 684896 6296543 WW ord fault U 0 185 60 684899 6296557 WW ord fault U 0 135 65 684921 6296581 WW ord fault U 0 20 40 684933 6296600 WW ord fault U 0 250 75 684950 6296564 WW ord fault U 0 210 40 684932 6296558 WW ord fault U 0 130 60 684929 6296551 WW ord fault U 0 160 70 684922 6296542 WW ord fault U 0 195 50 684923 6296544 WW ord fault U 0 160 65 684919 6296537 WW ord fault U 0 65 70 684947 6296624 WW ord fault? U 0 105 60 684944 6296623 WW ord fault U 0 350 35 684969 6296648 WW ord fault U 0 100 75 684960 6296643 WW ord fault? U 0 170 70 684969 6296648 WW ord fault U 0 5 60 684974 6296661 WW ord fault? U 0 70 40 684989 6296677 WW ord fault U 0 50 80 684996 6296721 WW ord fault U 0 150 50 684995 6296759 WW ord fault U 0 320 35 684995 6296782 WW ord fault U 0 110 50 684985 6296832 WW ord fault U 0 190 60 684973 6296854 WW ord fault U 0 115 65 684942 6296898 WW ord fault U 0 125 40 684928 6296916 WW ord fault U 0 110 40 684925 6296918 WW ord fault U 0 35 60 684911 6296935 WW ord fault U 0 100 65 684907 6296941 WW ord fault U 0 130 70 684906 6296950 WW ord fault U 0 180 60 684881 6296977 WW ord fault U 0 110 75 684880 6296977 WW ord fault U 0 35 60 684873 6297007 WW ord fault U 0 290 40 684867 6297025 155 station lithology measurement sense class strike dip Easting Northing WW ord fault U 0 15 40 684866 6297026 WW ord fault U 0 290 45 684866 6297037 WW ord fault U 0 40 65 684863 6297041 WW ord fault U 0 290 60 684860 6297048 WW ord fault U 0 270 45 684857 6297053 WW ord fault U 0 350 35 684858 6297070 WW ord fault U 0 315 55 684858 6297074 WW ord fault U 0 60 50 684855 6297084 WW ord fault U 0 120 45 684857 6297107 WW ord fault U 0 135 35 684856 6297116 WW ord fault U 0 40 35 684857 6297115 WW ord fault U 0 310 75 684860 6297123 WW ord fault U 0 285 55 684850 6297138 WW ord fault U 0 115 30 684845 6297145 WW ord fault U 0 70 40 684835 6297159 WW ord fault U 0 60 35 684824 6297173 WW ord fault U 0 340 55 684820 6297180 WW ord fault U 0 305 55 684819 6297189 WW ord fault U 0 15 50 684830 6297203 WW ord fault U 0 90 55 684852 6297213 WW ord fault U 0 195 70 684855 6297220 WW ord fault U 0 165 50 684843 6297229 WW ord fault U 0 180 65 684851 6297251 WW ord fault U 0 355 60 684863 6297258 WW ord fault U 0 25 50 684876 6297273 WW ord fault U 0 155 65 684878 6297275 WW ord fault U 0 20 60 684894 6297288 WW ord fault U 0 110 50 684900 6297294 WW ord fault U 0 140 60 684907 6297300   156 Appendix III: Drillcore Logs  The Silurian Waugoola Group was examined in drillcore, and the following graphic core logs were produced.  Drillcore was logged both on-site and from digital photographs provided by Newcrest Mining Ltd. in order to differentiate lithology and identify major structures.  Detail was recorded at the 1:200 scale.  These logs were used to constrain cross sections and better understand the Waugoola Group architecture, specifically at Cadia East. A reference map is provided to show the locations of drillhole collars. Abbreviations used are as follows: Bst = Mesozoic basalt cover; Ss = Waugoola Group sandstone; Ss-Si = Waugoola Group interbedded siltstone and sandstone; Si = Waugoola Group siltstone; Cgl = Waugoola Group conglomerate; CIC = Cadia Intrusive Complex; FRV = Forest Reefs Volcanics; Skn = magnetic skarn; Wm = Weemalla Formation. 157 0 0.1 0.2 km Projection:  Australian Map Grid Datum:  AGD66 Zone 55 G ib b Powerlin e Cop per Gull y Cat Cadiangullong CADIA HILL CADIA EAST N Faults Bst Ss Ss-Si Si Cgl CIC FRV Skn Wm CADIA HILL + + + ++ + + + + + + + + + + + + + + + + + + + + + + + + + ++ + + + + + + + + + + + + + + + + + NC464 NC205 NC482 CE159 CE150 CE136 CE134 CE131 CE108 CE096 CE092 CE087 CE075 CE073 CE069 CE064 CE055 CE053 CE040 CE009 CE007 CE006 CE003 CE002 CE001 NC363 NC255 NC242NC195 CE161 CE139 CE114 CE113 CE109 CE106 CE105 CE100 CE098 CE097 CE079 CE076 CE070 CE065CE04905 CE004 PC404 PC403 PC402 PC400 Figure  3.21 Figure 2.11 Fig ure  2.1 3 158 20 40 60 80 10 0 12 0 14 0 16 0 18 0 20 0 22 0 24 0 26 0 28 0 SCALE (m) TRUE DEPTH Sa n d st o n e Si lt st o n e B la ck  S h al e A rk o se C o n g lo m er at e Li m es to n e U n d iff er en ti at ed B as em en t Fa u lt U n co n fo rm it y B re cc ia LE G EN D D ri llc o re  L o g s:   C E H o le s 0 0 1 -0 4 0 C E0 40 C E0 09 C E0 07 C E0 06 C E0 03 C E0 02 C E0 01 ?? 159 20 40 60 80 10 0 12 0 14 0 16 0 18 0 20 0 22 0 24 0 26 0 28 0 SCALE (m) TRUE DEPTH Sa n d st o n e Si lt st o n e B la ck  S h al e A rk o se C o n g lo m er at e Li m es to n e U n d iff er en ti at ed B as em en t Fa u lt U n co n fo rm it y B re cc ia LE G EN D D ri llc o re  L o g s:   C E H o le s 0 5 3 -0 7 3 C E0 73 C E0 69 C E0 64 C E0 55 C E0 53 C E0 70 C E0 65 160 20 40 60 80 10 0 12 0 14 0 16 0 18 0 20 0 22 0 24 0 26 0 28 0 SCALE (m) TRUE DEPTH D ri llc o re  L o g s:   C E H o le s 0 7 5 -0 9 7 C E0 96 C E0 92 C E0 87 C E0 75 C E0 97 C E0 79 C E0 76 Sa n d st o n e Si lt st o n e B la ck  S h al e A rk o se C o n g lo m er at e Li m es to n e U n d iff er en ti at ed B as em en t Fa u lt U n co n fo rm it y B re cc ia LE G EN D 161 20 40 60 80 10 0 12 0 14 0 16 0 18 0 20 0 22 0 24 0 26 0 28 0 SCALE (m) TRUE DEPTH D ri llc o re  L o g s:   C E H o le s 0 9 8 -1 3 4 Sa n d st o n e Si lt st o n e B la ck  S h al e A rk o se C o n g lo m er at e Li m es to n e U n d iff er en ti at ed B as em en t Fa u lt U n co n fo rm it y B re cc ia LE G EN D C E1 34 C E1 31 C E1 09 C E1 06 C E1 05 C E1 00 C E0 98 162 20 40 60 80 10 0 12 0 14 0 16 0 18 0 20 0 22 0 24 0 26 0 28 0 SCALE (m) TRUE DEPTH D ri llc o re  L o g s:   C E H o le s 1 0 8 -1 5 9 C E1 59 C E1 50 C E1 36 C E1 08 C E1 39 C E1 14 C E1 13 Sa n d st o n e Si lt st o n e B la ck  S h al e A rk o se C o n g lo m er at e Li m es to n e U n d iff er en ti at ed B as em en t Fa u lt U n co n fo rm it y B re cc ia LE G EN D 163 20 40 60 80 10 0 12 0 14 0 16 0 18 0 20 0 22 0 24 0 26 0 28 0 SCALE (m) TRUE DEPTH N C 46 4 N C 20 5 N C 48 2 N C 36 3 N C 25 5 N C 24 2 N C 19 5 Sa n d st o n e Si lt st o n e B la ck  S h al e A rk o se C o n g lo m er at e Li m es to n e U n d iff er en ti at ed B as em en t Fa u lt U n co n fo rm it y B re cc ia LE G EN D D ri llc o re  L o g s:   N C  H o le s 164 D ri llc o re  L o g s:   P C  H o le s PC 40 4 PC 40 3 ? PC 40 2 PC 40 0 20 40 60 80 10 0 12 0 14 0 16 0 18 0 20 0 22 0 24 0 26 0 28 0 SCALE (m) TRUE DEPTH Sa n d st o n e Si lt st o n e B la ck  S h al e A rk o se C o n g lo m er at e Li m es to n e U n d iff er en ti at ed B as em en t Fa u lt U n co n fo rm it y B re cc ia LE G EN D 165

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