DOCSLIB.ORG

Mapping Alteration Systems in the Eastern Gawler Craton

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Mapping Alteration Systems in the Eastern Gawler Craton Mapping alteration systems in the eastern Gawler Craton Adrian Fabris Geological Survey of South Australia #GSSADD17 Mapping alteration systems in the eastern Gawler Craton Key points 1. Na and K alteration provides broad alteration footprints around IOCG’s and that there are distinct trends in the eastern Gawler that demonstrate a range of crustal depths. 2. Magnetics and gravity map alteration associated with IOCG’s. Magnetic data map the roots of an IOCG system and provide an understanding of fluid pathways. 3. Trace element geochemistry can be used to map footprints and vector in IOCG systems. #GSSADD17 Eastern Gawler Craton Mineral Systems New data from exiting Dh’s 1. Re-assaying of select intervals (>2700) from 112 diamond drillholes (2012-2015) 2. Multi-element geochemistry (65 elements) 3. Spectral mineralogy (>300 dh’s HyLogged) 4. Petrophysical properties Sampled dh’s #GSSADD17 Residual gravity IOCG Deposit Class • Fe oxide-Cu-Au breccia deposits e.g. Olympic Dam • Magnetite-apatite deposits (Kiruna-type) • Iron sulfide Cu-Au deposits Loose classification leads to confusion both to the genetic model and to • Sediment-hosted Fe oxide-Cu-Au deposits understanding the alteration system • Ironstone replacement Au-Cu deposits • Cu-Au-Fe skarn deposits • Carbonatite-Fe-oxide-F-REE deposits #GSSADD17• Cu-Au-Fe porphyry (alkalic) deposits Alteration Model Alteration facies Deposit styles Silicification Epithermal (<250°C) • Provides explanation Hematite-group IOCG Low T K-Fe-H-CO2 of why we see an Hem-Kfs/Musc-Carb-Chl- Cu-Au-Ag-REE-U-Mo array of deposit sulfides e.g. Olympic Dam (<350°C) styles IOCG Mag to Hem transition Polymetallic skarn IOCG Distal to heat source heat to Distal • late shallow, T, Low Based on Great Bear Kfs/Cpx-Grt-Kfs-sulfides Cu-Pb-Zn polymetallic IOCG terrain Potassic e.g. Pernatty Lagoon prospects • Evolving fluid High T K-Fe Magnetite-group IOCG Mag-Bt/Kfs-sulfides Cu-Au-Co e.g. Manxman, Cloncurry elements at each stage stage each at elements IOA Magnetite-apatite High T Ca-Fe ± Mg (+skarn) ealier Amp-Mag ± Cpx-Ap-Ttn IOA Fe, P, V, Th, REE Corriveau, L., Montreuil, J.-F., and Potter, E.G., 2016, Alteration facies (largely barren of sulfides) or recharges/discharges evolves Fluid e.g. Kiruna type, ?Cairn Hill linkages among iron oxide copper-gold, iron (<800°C) oxide-apatite, and affiliated Na ± Ca (albities) deposits in the Great Bear Magmatic zone, Northwest Territories, Canada: Ab-Scp-Qz-Zrn-Rt High T, deeper, deeper, T, High Economic Geology, v. 111, p. 2045–2072. core Thermal #GSSADD17 Sodic (<600°C) After Corriveau et al., 2016 What are the implications? Coober Pedy Mapping sodic and potassic alteration in the eastern Gawler Craton Olympic Dam • Sodic and potassic alteration will provide evidence for this process and give broad footprints Potassic Sodic Background #GSSADD17 Mapping regional potassic and sodic alteration MALD1 – Alford West HyLogger#GSSADD17TM Wallaroo Group Spectral data available Spectral data compiled • Spectral data provides a powerful tool for mapping alteration mineralogy. It is now available within a single spreadsheet making it more user friendly (Simon van der Wielen) • Spreadsheets – TIR 143 columns (>125 000 metre intervals), SWIR/VNIR 112 columns (>209 000 metre intervals) #GSSADD17 Alteration Model Alteration facies Deposit styles Implications Silicification Epithermal • Early stages of alteration (<250°C) provide crucial ground Hematite-group IOCG Low T K-Fe-H-CO2 preparation Hem-Kfs/Musc-Carb-Chl- Cu-Au-Ag-REE-U-Mo sulfides e.g. Olympic Dam • All IOCG’s will have a (<350°C) magnetic response related to IOCG Polymetallic skarn IOCG Distal to heat source heat to Distal early magnetite-alteration late shallow, T, Low Cu-Pb-Zn polymetallic phase (magnetics ideal Mag to Hem transition e.g. Pernatty Lagoon prospects mapping tool). Kfs/Cpx-Grt-Kfs-sulfides High T K-Fe Magnetite-group IOCG Mag-Bt/Kfs-sulfides Cu-Au-Co e.g. Manxman, Cloncurry elements at each stage stage each at elements IOA Magnetite-apatite High T Ca-Fe ± Mg (+skarn) ealier Amp-Mag ± Cpx-Ap-Ttn IOA Fe, P, V, Th, REE Corriveau, L., Montreuil, J.-F., and Potter, Fluid evolves or recharges/discharges or recharges/discharges evolves Fluid E.G., 2016, Alteration facies Magnetite (largely barren of sulfides) e.g. Kiruna type, ?Cairn Hill linkages among iron oxide copper-gold, iron (<800°C) oxide-apatite, and affiliated Na ± Ca (albities) deposits in the Great Bear Magmatic zone, Northwest Territories, Canada: Ab-Scp-Qz-Zrn-Rt High T, deeper, deeper, T, High Economic#GSSADD17 Geology, v. 111, p. 2045–2072. (<600°C) core Thermal After Corriveau et al., 2016 Mapping alteration through magnetic response Olympic Dam 10km 10km #GSSADD17 Residual gravity Residual magnetics Mapping alteration through magnetic response Emmie Bluff/Intercept Hill Intercept Hill Intercept Hill Structure and probably source Emmie Bluff Emmie Bluff North North Selected Dh’s Selected Dh’s Emmie Bluff Emmie Bluff South South 10km 5km 5km #GSSADD17 Residual gravity Residual magnetics Mapping alteration through magnetic response Punt Hill Groundhog Groundhog Groundhog Punt Hill Red Lake 5km 500m Residual magnetics Selected Dh’s Residual gravity Residual magnetics #GSSADD17 Magnetic inversion Mapping alteration through magnetic response Take home message • Magnetics and gravity data are critical in mapping alteration in IOCG systems. Magnetics also provide an understanding of the fluid pathways and regions that have seen the paragenetically early or deeper part of an IOCG system. 5km Residual magnetic s #GSSADD17 Magnetic inversion Scale reduction How to determine if it’s a significant system? • Sodic and potassic alteration give regional trends • Magnetics and gravity narrow down the search space but…. one of the challenges is not just understanding where we are in the alteration system, but whether it is a significant system • Trace element chemistry can certainly help! #GSSADD17 Forming trace element halos • Process of feldspar alteration in these systems leads to porosity that is filled with numerous and varied inclusions including Fe oxides, Fe sulfides. E.g. pyrite = mechanism of forming trace element footprints • Widespread alteration = large trace element ‘footprints’. Kontonikas-Charos A, Ciobanu CL, Cook NJ, Ehrig K, Krneta A and Kamenetsky VS 2017. Feldspar evolution in the Roxby Downs Granite, host to Fe- #GSSADD17oxide Cu-Au-(U) mineralization at Olympic Dam, South Australia. Ore Geology Reviews 80 p. 838-859. Mapping trace element halos Trace element associations • Integration of alteration and chemistry can be used to define elements associated with each deposit style (Fabris et al., 2013) • Hematite-dominated IOCG: Au, Ag, As, Ba, Bi, Cd, Ce, Co, Cu, Fe, La, Mn, Mo, Nd, REE, Re, S, Sb, Se, Te, W± U • Magnetite-dominated IOCG: Au, Ca, Ce, Co, Cu, Fe, Mo, Nd, P, Pb, REE, Re, S, Se, Te, U, Zn • Magnetite-dominated systems lack strong association with As, Ag, Bi, Sb and W i.e. elements typically associate with lower T fluids in hydrothermal systems. #GSSADD17 Prominent Hill Mapping trace element halos Carrapateena Sb Trace element associations Emmie Bluff • As, Bi, Sb and W show widespread anomalism in the central Olympic Cu-Au Province (cooler phase) #GSSADD17 Prominent Hill Mapping trace element halos Carrapateena Ce Trace element associations Emmie Bluff • Elements such as Ce (LREE), Te, Nd, Re are associated with the centre of the system. Tea Tree Glen #GSSADD17 Mapping trace element halos IHAD3 Cu IHAD6 • Widespread Cu anomalism (no clear vector). IHAD5 IHAD2 #GSSADD172km Mapping trace element halos IHAD3 Sb IHAD6 • low T elements give high values across all holes {As, IHAD5 Bi, Sb, W} IHAD2 #GSSADD172km Mapping trace element halos IHAD3 Ce IHAD6 • Elements associated with both mag-dom and hem IHAD5 dom mineralisation, and IHAD2 don’t tend to be mobile {Ce, Nd, Re +/- Te). • May demonstrate a greater proportion of magmatic- hydrothermal fluids in the east. #GSSADD172km Mapping alteration systems in the eastern Gawler Craton Conclusions 1. Na and K alteration trends demonstrate the range of crustal depths in the eastern Gawler and therefore style of IOCG’s to look for. 2. Magnetic data map the roots of an IOCG system and provide an understanding of fluid pathways. 3. Trace element geochemistry can be used to vector within an IOCG system with certain elements potentially indicating the source of low T and high T fluids. #GSSADD17 Disclaimer The information contained in this presentation has been compiled by the Department of the Premier and Cabinet (DPC) and originates from a variety of sources. Although all reasonable care has been taken in the preparation and compilation of the information, it has been provided in good faith for general information only and does not purport to be professional advice. No warranty, express or implied, is given as to the completeness, correctness, accuracy, reliability or currency of the materials. DPC and the Crown in the right of the State of South Australia does not accept responsibility for and will not be held liable to any recipient of the information for any loss or damage however caused (including negligence) which may be directly or indirectly suffered as a consequence of use of these materials. DPC reserves the right to update, amend or supplement the information from time to time at its discretion. #GSSADD17 Contact minerals.dpc.sa.gov.au/gssa_dd Department of the Premier and Cabinet - Mineral Resources Division Geological Survey of South Australia Level 4, 101 Grenfell Street Adelaide, South Australia 5000 T: +61 8 8463 3000 E: [email protected] #GSSADD17.
Load more

Recommended publications
  • What Lies Beneath the Western Gawler Craton? Interpretations and Implications from Deep Crustal Seismic Reflection Profile 13GA-EG1
    What lies beneath the western Gawler Craton? Interpretations and implications from deep crustal seismic reflection profile 13GA-EG1 Wise, Tom 1; Dutch, Rian 1,2 ; Pawley, Mark 1; Doublier, Michael 3, Kennett, Brian 4, Fraser, Geoff 3, Clark, Dan 3 and Thiel, Stephan 1,2 1Geological Survey of South Australia, Department of State Development, Adelaide, South Australia 2 School of Physical Sciences, University of Adelaide, Adelaide, South Australia 3Resources Division, Geoscience Australia, Canberra, ACT 4 Research School of Earth Sciences, Australian National University, Canberra, ACT The eastern section of deep seismic reflection profile 13GA-EG1, here referred to as 13GA-EG1E, starts at Tarcoola in the central Gawler Craton and extends west across the predominantly covered western Gawler Craton, and into the thickly covered Coompana Province. Limited control on the crystalline basement imaged by this seismic transect is available to aid seismic interpretation, as outcrop and drilling are sparse. Neoproterozoic-recent cover thickens to the western end of 13GA-EG1E, with the Neoproterozoic-Ordovician Officer Basin and Cenozoic Eucla Basin combining to provide a cover thickness of up to ~2.5 km. Hence, the seismic profile is a crucial tool for understanding the geology and crustal evolution of this area. The upper crust of the Gawler Craton can be sub-divided into three distinct domains, corresponding to domains previously defined by aeromagnetics. The Wilgena Domain, at the eastern end of the profile, is characterised by apparent east-dipping structures, whereas the Christie and Nawa Domains predominantly contain apparent west-dipping structures. Some of these upper crustal structures can be traced to greater depths, where they either flatten out in the lower crust, or in several cases, offset the Moho.
    [Show full text]
  • View Annual Report
    ANNUAL REPORT OZ MINERALS ANNUAL REP MINERALSOZ ANNUAL 2012 OZ MINERALS LIMITED ABN 40 005 482 824 O RT 2012 RT A MODERN MINING COMPANY CONTENTS 1 Results for Announcement to the Market 3 Chairman and Managing Director & CEO’s Letter 4 Corporate Governance Statement 10 Directors’ Report 23 Remuneration Overview 27 Remuneration Report 45 Auditor’s Independence Declaration 46 Consolidated Income Statement 47 Consolidated Statement of Comprehensive Income 48 Consolidated Statement of Changes in Equity 49 Consolidated Balance Sheet 50 Consolidated Statement of Cash Flows 51 Notes to the Consolidated Financial Statements 92 Directors’ Declaration 93 Independent Auditor’s Report 95 Shareholder Information IBC Contact Details Computer generated wire frame Front cover: Front model of the Prominent Hill underground development. RESULTS FOR ANNOUNCEMENT TO THE MARKET Provided below are the results for announcement to the market in accordance with Australian Securities Exchange (‘ASX’) Listing Rule 4.2A and Appendix 4E for the Consolidated Entity (‘OZ Minerals’ or the ‘Consolidated Entity’) comprising OZ Minerals Limited (‘OZ Minerals Limited’ or the ‘Company’) and its controlled entities for the year ended 31 December 2012 (the ‘financial year’) compared with the year ended 31 December 2011 ('comparative year'). Highlights • Safety programs continue to drive improved safety performance at Prominent Hill • A solid operational performance for the year with OZ Minerals’: o Revenue of $985.7 million; 1 o Underlying EBITDA of $334.1 million; and o Net
    [Show full text]
  • GSA TODAY North-Central, P
    Vol. 9, No. 10 October 1999 INSIDE • 1999 Honorary Fellows, p. 16 • Awards Nominations, p. 18, 20 • 2000 Section Meetings GSA TODAY North-Central, p. 27 A Publication of the Geological Society of America Rocky Mountain, p. 28 Cordilleran, p. 30 Refining Rodinia: Geologic Evidence for the Australia–Western U.S. connection in the Proterozoic Karl E. Karlstrom, [email protected], Stephen S. Harlan*, Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131 Michael L. Williams, Department of Geosciences, University of Massachusetts, Amherst, MA, 01003-5820, [email protected] James McLelland, Department of Geology, Colgate University, Hamilton, NY 13346, [email protected] John W. Geissman, Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131, [email protected] Karl-Inge Åhäll, Earth Sciences Centre, Göteborg University, Box 460, SE-405 30 Göteborg, Sweden, [email protected] ABSTRACT BALTICA Prior to the Grenvillian continent- continent collision at about 1.0 Ga, the southern margin of Laurentia was a long-lived convergent margin that SWEAT TRANSSCANDINAVIAN extended from Greenland to southern W. GOTHIAM California. The truncation of these 1.8–1.0 Ga orogenic belts in southwest- ern and northeastern Laurentia suggests KETILIDEAN that they once extended farther. We propose that Australia contains the con- tinuation of these belts to the southwest LABRADORIAN and that Baltica was the continuation to the northeast. The combined orogenic LAURENTIA system was comparable in
    [Show full text]
  • The Crustal Geophysical Signature of a World-Class Magmatic Mineral System
    www.nature.com/scientificreports OPEN The crustal geophysical signature of a world-class magmatic mineral system Received: 29 January 2018 Graham Heinson 1, Yohannes Didana1, Paul Soefy1, Stephan Thiel 1,2 & Tom Wise2 Accepted: 2 July 2018 World-class magmatic mineral systems are characterised by fuid/melt originating in the deep crust and Published: xx xx xxxx mantle. However, processes that entrain and focus fuids from a deep-source region to a kilometre-scale deposit through the crust are unclear. A magnetotelluric (MT) and refection seismic program across the margin of the Gawler Craton, Australia yield a distinct signature for a 1590 Ma event associated with emplacement of iron-oxide copper gold uranium (IOCG-U) deposits. Two- and three-dimensional MT modelling images a 50 km wide lower-crustal region of resistivity <10 Ωm along an accreted Proterozoic belt. The least resistive (~1 Ωm) part terminates at the brittle-ductile transition at ~15 km, directly beneath a rifted sedimentary basin. Above the brittle-ductile transition, three narrow low- resistivity zones (~100 Ωm) branch to the surface. The least resistive zone is remarkably aligned with the world-class IOCG-U Olympic Dam deposit and the other two with signifcant known IOCG-U mineral occurrences. These zones are spatially correlated with narrow regions of low seismic refectivity in the upper crust, and the deeper lower-crust conductor is almost seismically transparent. We argue this whole-of-crust imaging encapsulates deep mineral system and maps pathways of metalliferous fuids from crust and mantle sources to emplacement at discrete locations. World-class magmatic ore systems are ofen characterised by fuids/melts that are derived from deep lithosphere, mostly located at the margins of ancient craton1–6.
    [Show full text]
  • Collaboration Delivers NEW INFORMATION to Support MINERAL EXPLORATION
    ISSUE 78 June 2005 Collaboration delivers NEW INFORMATION to support MINERAL EXPLORATION As part of the National Geoscience Accord, Geoscience Australia is collaborating closely with its state and territory counterparts in regional geoscientific studies to encourage mineral exploration. GA is partnering with the Northern Territory Geological Survey (NTGS) and the Geological Survey of Western Australia (GSWA) on the North Australia and Tanami projects. In the Gawler Craton, we are collaborating with Primary Industry and Resources, South Australia (PIRSA) on the Gawler Project. The recently released NTGS Report 18, ‘Gold mineral system of the Tanami region’, by Wygralak et al (order at www.minerals.nt.gov.au/ntgs/) documents the results of a joint NTGS–GA study on the genesis and geological controls on lode gold deposits in the Tanami region. This report emphasises the importance of second-order structures associated with the D5 deformation event dated at younger than 1815 million years, and emphasises the range of pressures and temperatures of ore formation and the role of fluid reduction as a gold trapping mechanism. More joint reports to come Forthcoming joint reports with the NTGS include ‘Geology and origin of some Cu–Pb–Zn (–Au–Ag) deposits in the Strangways Metamorphic Complex, Arunta Region, Northern Territory’ by Hussey et al, which will document the geology and genesis of Zn–Pb–Cu–Ag and Cu–Au deposits in the eastern Arunta to the east-north-east of Alice Springs. A series of reports by Worden and co-workers will summarise the results of joint geochronology studies through the Northern Territory. Joint work with GSWA on prospects in the western Tanami region will also be released as a GSWA report entitled ‘Preliminary studies of the geologic setting of lode gold deposits in the western Tanami region, Western Australia’ by Bagas et al.
    [Show full text]
  • The Olympic Cu-Au Province, Gawler Craton: a Review of the Lithospheric Architecture, Geodynamic Setting, Alteration Systems, Cover Successions and Prospectivity
    minerals Review The Olympic Cu-Au Province, Gawler Craton: A Review of the Lithospheric Architecture, Geodynamic Setting, Alteration Systems, Cover Successions and Prospectivity Anthony Reid 1,2 1 Geological Survey of South Australia, Department for Energy and Mining, Adelaide, SA 5001, Australia; [email protected]; Tel.: +61-8-8463-3000 2 Department of Earth Sciences, University of Adelaide, Adelaide, SA 5005, Australia Received: 29 May 2019; Accepted: 19 June 2019; Published: 20 June 2019 Abstract: The Olympic Cu-Au Province is a metallogenic province in South Australia that contains one of the world’s most significant Cu-Au-U resources in the Olympic Dam deposit. The Olympic Cu-Au Province also hosts a range of other iron oxide-copper-gold (IOCG) deposits including Prominent Hill and Carrapateena. This paper reviews the geology of the Olympic Cu-Au Province by investigating the lithospheric architecture, geodynamic setting and alteration systematics. In addition, since the province is almost entirely buried by post-mineral cover, the sedimentary cover sequences are also reviewed. The Olympic Cu-Au Province formed during the early Mesoproterozoic, ca. 1.6 Ga and is co-located with a fundamental lithospheric boundary in the eastern Gawler Craton. This metallogenic event was driven in part by melting of a fertile, metasomatized sub-continental lithospheric mantle during a major regional tectonothermal event. Fluid evolution and multiple fluid mixing resulted in alteration assemblages that range from albite, magnetite and other higher temperature minerals to lower temperature assemblages such as hematite, sericite and chlorite. IOCG mineralisation is associated with both high and low temperature assemblages, however, hematite-rich IOCGs are the most economically significant.
    [Show full text]
  • The Coompana Province: Regional Context
    The Coompana Province Regional Context R.A. Dutch Coompana Exploration Release Areas Industry Information Session, Tonsley, May 2016 The Coompana Province • Covers an area of approximately 200 000 km2, straddling the border between South Australia and Western Australia • Bound to the west by the Mundrabilla shear zone, the north by the Musgrave Province, the east by the Gawler Craton and likely extends off shore to the continental margin Arunta Province Musgrave Province Yilgarn Craton Coompana Province AFO Gawler Craton Department of State Development 2 The Coompana Province • There are no known exposed basement rocks of the Coompana Province, with the region being extensively covered by sediments of the Officer, Denman, Bight and Eucla basins Department of State Development 3 The Coompana Province • Due to the often unknown thickness of cover in many places, and the lack of exploration or stratigraphic drilling, very little is known about the basement units Currently • 6 cored basement intersections • 8 percussion basement intersections Mulyawara 1 • 4 intersections into younger basalt Kutjara 1 Lake Maurice E FOR 010 Adi 1 Ooldea 1, 2 & 3 FOR 011 FOR 008 BN 1 & 2 Nullarbor Plains 7 FOR 012FOR 004 CD 1KN 1 Guinewarra Bore Malabie 1 Alballa-Karoo Eucla 1 Potoroo 1 – Off shore Department of State Development 4 Regional Time-Space Plot Department of State Development 5 Regional Time-Space Plot Department of State Development 6 Regional Time-Space Plot Department of State Development 7 Oceanic pre-cursors • No direct evidence of rocks of
    [Show full text]
  • Geomorphology of the Acraman Impact Structure, Gawler Ranges, South Australia
    Cadernos Lab. Xeolóxico de Laxe Coruña. 2010. Vol. 35, pp. 209 - 220 ISSN: 0213-4497 Geomorphology of the Acraman impact structure, Gawler Ranges, South Australia WILLIAMS, G.E.1 and GOSTIN, V.A. 1 (1) Discipline of Geology and Geophysics, School of Earth and Environmental Sciences, University of Adelaide, SA 5005, Australia Abstract The late Neoproterozoic Acraman impact structure occurs mostly in felsic volcanic rocks (Mesoproterozoic Gawler Range Volcanics) in the Gawler Ranges, South Australia, and strongly influences the topography of the region. The structure is expressed topographically by three main features: a near-circular, 30 km diameter low-lying area (Acraman Depression) that includes the eccentrically placed Lake Acraman playa; a partly fault-controlled arcuate valley (Yardea Corridor) at 85–90 km diameter; and arcuate features at 150 km diameter that are visible on satellite images. Geological and geomorphological observations and apatite fission-track data indicate that Acraman is eroded several kilometres below the crater floor, with the structure originally comprising a transient cavity about 40 km in diameter and a final structural rim 85–90 km in diameter. Ejecta of shock- deformed fragments of felsic volcanic rock up to 20 cm across derived from the Acraman impact form an extensive horizon ≤40 cm thick in Ediacaran (about 580 Ma) shale in the Adelaide Geosyncline 240–370 km to the east of the impact site. A correlative band ≤7 mm thick of sand-sized ejecta occurs in mudstone in the Officer Basin up to 540 km to the northwest of Acraman. The dimensions of the impact structure and the geochemistry of the ejecta horizon imply that the bolide was a chondritic asteroid >4 km in diameter.
    [Show full text]
  • 12 Groundwater 12
    GROUNDWATER 12 12.1 INTRODUCTION and the potential impact on users of the groundwater resources 12 and other sensitive receptors. Olympic Dam is located in an area of low rainfall, low rates of groundwater flow and recharge, and low topographic relief. No groundwater affecting activities would occur as a result of As a consequence, most groundwater within 50 km or more of construction or operation of the proposed concentrate handling the current operation is saline (i.e. salty) and little-used. facilities at the Port of Darwin. These facilities would be Olympic Dam currently uses less than 1 ML/d of local constructed within the reclaimed area of the East Arm where groundwater for dust suppression, and there are three known groundwater is not naturally occurring. Consequently, the local shallow groundwater wells within 50 km that use saline and regional groundwater systems of the Darwin area are not groundwater for stock (all three are within pastoral leases held discussed here. Information relating to the risk to groundwater by BHP Billiton). from accidental spills or leaks is discussed in Appendix E4. The primary water supply for the existing Olympic Dam Groundwater in the vicinity of the desalination plant would not operation is groundwater extracted from Wellfields A and B be used and the proposed expansion would not affect the located in the Great Artesian Basin (GAB), about 120 and natural interactions between groundwater and seawater. 200 km north of Olympic Dam, respectively. These wellfields supply an average of 37 ML/d to the existing operation. The The potential for, and implications of, water accumulating in extraction of groundwater is monitored extensively to the bottom of the open pit after mine closure are discussed demonstrate compliance with licence conditions and to prevent in Chapter 11, Surface Water.
    [Show full text]
  • Chapter 2 Tectonic Setting of Australia
    Chapter 2 Tectonic Setting of Australia The Australian continent comprises a number of different tectonic blocks: Archaean and Proterozoic blocks in the western and central parts and rela- tively younger units (Phanerozoic) in the east. The Archaean Cratons are some of the Earth’s oldest regions and carry information from the very early geological history of the Earth when the supercontinents were present and the tectonic processes possibly different from today (Betts et al., 2002). The sep- aration of Australia and Antarctica, once part of the supercontinent Gond- wana, began around 160 Ma ago along the southern margin of the Australian continent. The process led to crustal thinning at the margin and the sepa- ration was complete by around 95 Ma ± 5 Ma. Another important feature of the continent is the geological boundary, between the Precambrian units in central Australia and Phanerozoic units in the east. This boundary is referred to as the Tasman Line. Since there is limited outcrop much of the transition has to be inferred from indirect evidence such as gravity and magnetic lineations. The Tasman Line concept is still a major source of debate regarding its age, current position and past position in Gondwana reconstructions (Direen & Crawford, 2003; Kennett et al., 2004). A geological summary map of the Australia is given at figure 2.1 which emphasizes the major blocks, with their age and inferred boundaries under sedimentary cover (heavy dashed lines). 2.1 Archaean Cratons 2.1.1 West Australia The Pilbara and Yilgarn Cratons located in the west cover the majority of West Australia.
    [Show full text]
  • Evidence for Early Mesoproterozoic Arc Magmatism in the Musgrave Block, Central Australia: Implications for Proterozoic Crustal
    Evidence for Early Mesoproterozoic Arc Magmatism in the Musgrave Block, Central Australia: Implications for Proterozoic Crustal Growth and Tectonic Reconstructions of Australia B. P. Wade, K. M. Barovich, M. Hand, I. R. Scrimgeour,1 and D. F. Close1 Continental Evolution Research Group, Geology and Geophysics, University of Adelaide, Adelaide, South Australia 5005, Australia (e-mail: [email protected]) ABSTRACT The Musgrave Block in central southern Australia separates the dominantly Paleoproterozoic North Australian Craton from the Late Archean to early Mesoproterozoic Gawler Craton in southern Australia. Geochemical and Nd isotopic data from ∼1.59–1.55-Ga felsic rocks in the Mann Ranges suggest that the early history of the Musgrave Block was linked to the development of subduction along the northern margin of the Gawler Craton. Characteristic geochemical patterns of these felsic rocks include negative anomalies in Nb, Ti, and Y and are accompanied by steep light rare ␧ Ϫ earth element patterns and comparatively juvenile Nd isotopic compositions ( Nd(1550) values from 1.2 to 0.9). The geochemical and isotopic signatures of these early Mesoproterozoic felsic rocks have similarities with island arc systems involving residual Ti-bearing minerals and garnet. We propose that the 1.59–1.55-Ga arclike rocks in the Musgrave Block indicate the presence of an active margin between the North Australian Craton and the South Australian Craton, with subsequent suturing of the Australian continent during the early Mesoproterozoic. The existence of arclike magmatism in the Musgrave Block during the early Mesoproterozoic suggests a period of major crustal growth in the Australian Proterozoic that has important implications for current Proterozoic reconstructions of Australia and Australia’s fit within the supercontinent Rodinia.
    [Show full text]
  • Performance Report 2020 2020
    St Barbara's Parish School St Barbara's Parish School Performance Report Performance Report 2020 2020 In 2020 8 classes were operating at the end of the year with a total staff of FTE 11.4 teachers and further support from several ESOs. Classes range from Foundation to Yr 9. In 2020 8 classes were operating at the end of the year with a total staff of FTE 11.4 teachers and further support from several ESOs. Classes range from Foundation to Yr 9. St Barbara's Parish School continues to provide Catholic Education for students in remote South Australia. Outstanding teaching practises combined with well-resourced classrooms, offers an St Barbaraexcellent's Parish education School continues for students to provide in Roxby Catholic Downs. Education for students in remote South Australia. Outstanding teaching practises combined with well-resourced classrooms, offers an excellent education for students in Roxby Downs. Contents Section One: School Context Section Two: Student Profile Section Three: Staffing Profile Section Four: Catholic Identity Section Five: Curriculum Section Six: Student Performance Section Seven: Continuous School Improvement Section Eight: Parent, Student and Teacher Satisfaction Section Nine: Finance Section One: School Context St Barbara's Parish School is a Catholic school situated in Roxby Downs remote mining town, 560 kilometres north of Adelaide. St Barbara's is now structured as an F to 6 primary and 7 to 9 middle school to maximise the use of the Australian Curriculum Framework. The school enjoys excellent facilities, especially in the ICT area with every student having 1:1 iPad access and offers a robust pastoral care program, emphasising the faith formation of students in the Catholic tradition and close involvement of families and a safe, supportive learning environment.
    [Show full text]