DOCSLIB.ORG

The Thermochronological Evolution of the Northern Gawler Craton and Adelaide Rift Complex, and Their Relation with the Structural Architecture

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Thermochronological Evolution of the Northern Gawler Craton and Adelaide Rift Complex, and Their Relation with the Structural Architecture The thermochronological evolution of the northern Gawler Craton and northern Adelaide Rift Complex James William Hall Department of Earth Sciences School of Physical Sciences The University of Adelaide October 2018 Table of contents Abstract v List of Figures vii List of Tables x Declaration xi Journal Articles xii Acknowledgements xiii Introduction and outlines 1 Introduction 1 Thesis outline 4 Chapter 1 – Apatite U-Pb map for the northern Gawler Craton 10 Statement of authorship 11 Abstract 13 1.1 Introduction 13 1.2 Geological setting 14 1.3 Methodology 19 1.4 Results 20 1.4.1 Nawa Domain 20 1.4.2 Coober Pedy Ridge & Mt. Woods Inlier 21 1.4.3 Christie Domain 26 1.4.4 Fowler Domain 28 1.4.5 Wilgena & Nuyts domains 29 1.5 Discussion 31 1.5.1 Palaeoproterozoic cooling 31 1.5.2 Mesoproterozoic cooling 32 1.5.3 Comparisons to pre-existing 40Ar-39Ar datasets and interpolation maps 34 1.6 Conclusions 35 1.7Acknowledgements 36 1.8 References 36 Chapter 2 – Thermal history of the northern Olympic Domain 41 Statement of authorship 42 Abstract 44 2.1 Introduction 44 2.2 Geological setting 45 2.2.1 Gawler Craton 45 2.2.2 Olympic Domain 45 2.2.3 Pandurra Formation, Stuart Shelf and Delamerian Orogeny 46 2.2.4 Post-Delamerian tectonics 48 i 2.2.5 Current regional geothermal gradient 48 2.3 Methodology 49 2.3.1 Rock sampling strategy 49 2.3.2 Apatite thermochronology methods 49 2.3.2.1 Apatite fission track method 52 2.3.2.2 Apatite U-Pb method 52 2.3.3 Potassium feldspar and muscovite 40Ar/39Ar dating 54 2.3.4 (U-Th-Sm)/He analysis 55 2.3.5 Radial plots and modelling 55 2.4 Results 59 2.4.1 Apatite U-Pb age data 59 2.4.2 40Ar/39Ar data 60 2.4.3 Apatite fission track, zircon (U-Th-Sm)/He and apatite (U-Th-Sm)/He data 62 2.4.4 Low-temperature thermochronological modelling 64 2.5 Discussion 65 2.5.1 Proterozoic 65 2.5.2 Palaeozoic 66 2.5.3 Mesozoic 67 2.5.4 Thermal anomalies within the Olympic Domain 69 2.5.5 Comparisons with neighbouring regions 70 2.6 Conclusions 70 2.7 Acknowledgements 71 2.8 References 71 Chapter 3 – Fault reactivation at the northern margin of the Gawler Craton 78 Statement of authorship 79 Abstract 81 3.1 Introduction 81 3.2 Geological setting 82 3.2.1 Gawler Craton 82 3.2.2 Karari Shear Zone 83 3.2.3 Phanerozoic tectonics 83 3.2.4 Offier and Arckaringa Basins 84 3.3 Methodology 84 3.3.1 Apatite fission track dating 84 3.3.2 Radial plots and thermal history modelling 87 3.4 Results 87 3.4.1 Mt. Woods Inlier 87 3.4.2 Nawa Domain 88 3.4.3 Coober Pedy Ridge and Christie Domain 91 3.4.4 Fowler Domain 95 ii 3.4.5 Thermal history modelling 96 3.5 Discussion 96 3.6 Conclusions 99 3.7 Acknowledgements 99 3.8 References 99 Chapter 4 - Constraining (hydro)thermal activity within the Willouran Ranges 105 Statement of authorship 106 Abstract 108 4.1 Introduction 108 4.2 Geological Setting 109 4.2.1 Stratigraphy of the Adelaide Rift Complex 109 4.2.2 Phanerozoic tectonics and hydrothermal activity 109 4.2.3 Domain sub-division 111 4.3 Methodology 114 4.3.1 Apatite fission track analysis 114 4.3.2 Apatite U-Pb analysis 114 4.3.3 Time-temperature models 115 4.4 Results 115 4.4.1 West Mount Domain 115 4.4.2 Rocky Point Sub-Domain and Berlina Domain 115 4.4.3 Kingston and Trial Hole Domains 116 4.4.4 Time-temperature models 125 4.5 Discussion 125 4.5.1 Regional cooling 125 4.5.2 Hydrothermally reset data 126 4.5.3 Comparisons with surrounding regions 127 4.6 Conclusions 128 4.7 Acknowledgements 129 4.8 References 129 Chapter 5 – Exhumation of the Peake and Denison Inliers 133 Statement of authorship 134 Abstract 136 5.1 Introduction 136 5.2 Geological Setting 138 5.3 Methodology 142 5.3.1 Apatite fission track dating 142 5.3.2 Apatite (U–Th–Sm)/He (AHe) and zircon (U–Th–Sm)/He (ZHe) dating 143 5.3.3 Titanite U-Pb dating 143 5.3.4 Radial plots and thermal history modelling 143 iii 5.4 Results 145 5.4.1 Apatite fission track data 145 5.4.2 (U–Th–Sm)/He thermochronology 147 5.4.3 Titanite U-Pb dating 148 5.4.4 Thermal history modelling 149 5.5 Discussion 151 5.5.1 Late Cambrian–Early Carboniferous 152 5.5.2 Middle Carboniferous–Middle Triassic 154 5.5.3 Mesozoic–Cenozoic 154 5.5.4 Comparison with exhumation studies within the Flinders Ranges 155 5.6 Conclusions 156 5.7 Acknowledgements 156 5.8 References 156 Summary and conclusions 163 References 166 Appendices 169 Appendix 1 169 iv Abstract Cratons preserve information about the deformation history of the surrounding terrains and the thermal history of mineral deposits. This thesis aims to constrain the effects on the Gawler Craton of various deformation events from surrounding terrains and the thermal evolution of mineralization within the Craton. Multi-method thermochronology was applied to samples throughout the northern Gawler Craton and Willouran Ranges of the Adelaide Rift Complex to unravel the thermal evolution of the northern Gawler Craton and Willouran Ranges. The subsequent thermal histories are compared and the differences between them highlighted. Apatite U-Pb data reveal distinct spatial patterns within the high temperature cooling history of the Gawler Craton. These spatial patterns correspond to the thermal response of a region to different magmatic and metamorphic events. The eastern Gawler Craton cooled to mid-crustal temperatures from high temperatures following magmatism of the ~1850 Ma Donington Suite and ~1590 Ma Hiltaba Suite while the central Gawler Craton cooling following the ~2500 Ma Sleaford and ~1700 Ma Kimban orogenies. The north-western Gawler Craton preserved evidence for deformation that post-dates cooling relating to magmatism with ages relating to the amalgamation of western and southern Australia at ~1300 Ma. In addition to the apatite U-Pb data, muscovite 39Ar/40Ar preserve post magmatic cooling within the Olympic Domain of the Hiltaba Suite at ~1530 Ma within the Olympic Domain. A second hydrothermally altered muscovite 39Ar/40Ar age from the same sample is recorded at ~1380 Ma. Potassium feldspar 39Ar/40Ar data from numerous samples all preserve altered spectra during the Neoproterozoic which corresponds to the deposition of the Adelaide Rift Complex. The region first cooled to low temperatures (<200 °C) at ~1000 Ma before minor reheating during the Neoproterozoic. The main low temperature regional cooling period is preserved at ~430 – 350 Ma and is interpreted to be caused by deformation relating to the 450 – 300 Ma Alice Springs Orogeny. Younger apatite fission track ages are only preserved in close proximity to major Iron- Oxide-Copper-Gold (IOCG) deposits and form a young thermal corridor linking the IOCG deposits. Apatite fission track data along the Karari Shear Zone of the northern Gawler Craton preserves evidence for regional Neoproterozoic cooling and a deformation event during the Carboniferous. The Nawa Domain preserves Carboniferous apatite fission track ages, whereas the Christie Domain preserves older Neoproterozoic – Cambrian ages. This is interpreted to be resultant from southward compression from the Alice Springs Orogeny and caused the Nawa Domain, to the north of the Karari Shear Zone, to thrust over the Christie Domain to the south. Additionally, this thrusting is interpreted to have ceased deposition of the Officer Basin sediments, which overlies the rocks to the north of the Karari Shear Zone. The deposition of the ~300 Ma Arckaringa Basin sediments indicates that once the compressional event stopped, deposition recommenced in the region. East of the Torrens Hinge Zone, apatite fission track analysis from sedimentary samples within the Willouran Ranges revealed cooling ranging from 550 to 100 Ma. U-Pb data records either detrital v Proterozoic ages or ages at ~250 Ma. This younger age is interpreted to be caused by hydrothermal activity located proximally to the major fault zones in the region. Samples which preserve this younger U-Pb age also preserve apatite fission track ages of ~100 Ma that is interpreted to be cooling. This hydrothermal activity correlates well with hydrothermal activity in the Mt. Painter Inlier, a region of established high heat flow ~150 km to the east. This hints toward a broader zone of hydrothermal activity related cooling during this time. Regional deformation events are consistently present throughout the study region, yet local thermal histories contain inconsistencies. These inconsistencies can be accounted for by differing key geological factors which are unique to each region. The thickness of any overlying sedimentary packages and the geothermal gradient are greatly important at any location as they considerably influence the local thermal histories. Major structures around the rim of the craton tend to control the thermal histories at both high and low temperatures, however, their orientation within the stress regime is important. The prior thermal history of a region can be reset and overprinted by hydrothermal activity as has been recorded in this study for regions within the Olympic Domain and the northern Adelaide Rift Complex. vi List of figures Chapter 1 Fig. 1.1 Simplified geological map of the Gawler Craton 15 Fig. 1.2 Simplified time-space plot of the Gawler Craton 17 Fig.
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]
  • EARLY COOBER PEDY SHOW HOME/DUGOUT - for SALE Coober Pedy Is a Town Steeped in the Rich History of Early Opal Mining and Its Related Industry Tourism
    ISSN 1833-1831 Tel: 08 8672 5920 http://cooberpedyregionaltimes.wordpress.com Thursday 19 May 2016 EARLY COOBER PEDY SHOW HOME/DUGOUT - FOR SALE Coober Pedy is a town steeped in the rich history of early opal mining and its related industry tourism. The buying and selling of dugouts is a way of life in the Opal Capital of the World where the majority of family homes are subterranean. A strong real-estate presence has always been evident in Coober Pedy, but opal mining family John and Jerlyn Nathan with their two daughters are self-selling their historic dugout in order to buy an acreage just out of town that will suit their growing family’s needs better. The Nathan family currently live on the edge of town, a few minutes from the school and not far from the shops. Despite they brag one of most historic homes around with a position and a view from the east side of North West Ridge to be envied, John tells us that his growing family needs more space outside. “Prospector’s Dugout has plenty of space inside, with 4 bedrooms plus,” said John. “But the girls have grown in 5 years and we have an opportunity, once this property is sold, to buy an acreage outside of town, and where my daughters can have a trail bike and other outdoor activities where it won’t bother anyone.” “I will regret relinquishing our location and view but I think kids need the freedom of the outdoors when they are growing up,’ he said. John and Jeryln bought the 1920’s dugout at 720 Russell John and Jerlyn Nathan with daughters De’ Arna and Darna on the patio at Prospector’s Dugout.
    [Show full text]
  • Safety in Opal Mining Guide
    Safety in Opal Mining Opal Miner’s Guide Coober Pedy Mine Rescue emergency phone number is 8672 5999. Andamooka Mine Rescue emergency phone numbers are (Police) 8672 7072, (Clinic) 8672 7087, (Post office) 8672 7007. Mintabie Mine Rescue emergency phone numbers are (clinic) 8670 5032, (SES) 8670 5162, 8670 5037 A.H. South Australia Opal Fields Disclaimer Information provided in this publication is designed to address the most commonly raised issues in the workplace relevant to South Australian legislation such as the Occupational Health Safety and Welfare Act 1986 and the Workers Rehabilitation and Compensation Act 1986. They are not intended as a replacement for the legislation. In particular, WorkCover Corporation, its agents, officers and employees : • make no representations, express or implied, as to the accuracy of the information and data contained in the publication, • accept no liability for any use of the said information or reliance placed on it, and make no representations, either expressed or implied, as to the suitability of the said information for any particular purpose. Awards recognition 1999 S.A Resources Industry Awards. Judges Citation for Safety Culture Development Awarded to Safety in Opal Mining Project. ISBN: 0 9585938 5 X Cover: Opals. Black Opals Majestic Opals Safety in Opal Mining Opal miner’s guide A South Australian Project. Funded by: The Mining and Quarrying Occupational Health and Safety Committee. Project Officer: Sophia Provatidis. With input from the miners of Coober Pedy, Mintabie, Andamooka and Lambina.
    [Show full text]
  • Coober Pedy, South Australia
    The etymology of Coober Pedy, South Australia Petter Naessan The aim of this paper is to outline and assess the diverging etymologies of ‘Coober Pedy’ in northern South Australia, in the search for original and post-contact local Indigenous significance associated with the name and the region. At the interface of contemporary Yankunytjatjara and Pitjantjatjara opinion (mainly in the Coober Pedy region, where I have conducted fieldwork since 1999) and other sources, an interesting picture emerges: in the current use by Yankunytjatjara and Pitjantjatjara people as well as non-Indigenous people in Coober Pedy, the name ‘Coober Pedy’ – as ‘white man’s hole (in the ground)’ – does not seem to reflect or point toward a pre-contact Indigenous presence. Coober Pedy is an opal mining and tourist town with a total population of about 3500, situated near the Stuart Highway, about 850 kilometres north of Adelaide, South Australia. Coober Pedy is close to the Stuart Range, lies within the Arckaringa Basin and is near the border of the Great Victoria Desert. Low spinifex grasslands amounts for most of the sparse vegetation. The Coober Pedy and Oodnadatta region is characterised by dwarf shrubland and tussock grassland. Further north and northwest, low open shrub savanna and open shrub woodland dominates.1 Coober Pedy and surrounding regions are arid and exhibit very unpredictable rainfall. Much of the economic activity in the region (as well as the initial settlement of Euro-Australian invaders) is directly related to the geology, namely quite large deposits of opal. The area was only settled by non-Indigenous people after 1915 when opal was uncovered but traditionally the Indigenous population was western Arabana (Midlaliri).
    [Show full text]
  • Dimdimaapril2020.Pdf
    2 In this issue: Comics Open House Stories 12 Boomslayer: The Mist 29 The Math Tutor 6 The Blackmailer 28 Secret Agent Zero 34 Vijay and the 36 The Wise Carpenter Anniversary Melon Plant 50 Haddiraj 23 50th Earth Day First & Foremost 32 Fastest Mammal Quest 26 Living Underground Fact-o-Meter 46 Q & A 42 Exotic Foods India File Nature Watch Movie Watch 44 The Ancient City of Lakes 24 My Winter Friend 29 Pawfect Entertainment Hall of Fame 9 Champion of the Curiosities Downtrodden 41 Book Bandit Bhavan’s Turning Point Dimdima Bring out the Winner in You 43 The Star Stroker April 2020 Vol. 4 Issue 11 PUBLISHED BY DR. A VENUGOPALAN, ON BEHALF OF Brain Power BHARATIYA VIDYA BHAVAN, 18, 20, EAST MADA STREET, MYLAPORE, CHENNAI-600 004 AND PRINTED BY 10 Teasers & Puzzles SHRI B. RAJ KUMAR AT RASI GRAPHICS, (P) LTD., NO. 40, PETERS ROAD, ROYAPETTAH, CHENNAI–600 014. 49 Word Whiz EDITOR: MAHUA GUHA 33 Poetry Nook CONSULTING EDITOR: MEERA NAIR ASSISTANT EDITOR: SHWETA MITTAL 45 It Happened to Me COPYRIGHTS: BHARATIYA VIDYA BHAVAN. ALL RIGHTS RESERVED THROUGHOUT THE WORLD. 47 Jokeshop EDITORIAL, CIRCULATION & DIMDIMA SUBSCRIPTION NEW DELHI OFFICE ADVERTISEMENTS Rs. 375/- for 12 issues. Bharatiya Vidya Bhavan Bharatiya Vidya Bhavan, Rs. 725/- for 24 issues. Mehta Sadan, K. G. Marg, Gora Gandhi Compound, Rs. 1050/- for 36 issues. New Delhi 110001 505, Sane Guruji Marg, Postage Free. Payment by MO or DD in favour Phone: 011-23381847 Tardeo, Mumbai 400034 of Bharatiya Vidya Bhavan payable at Mumbai. Phone: 022–23526025 & 23531991 Please include Rs.100/- extra if you want Email: [email protected] your copy to be sent by courier in Mumbai, CHENNAI OFFICE [email protected] Rs.200/- extra for outside Mumbai.
    [Show full text]
  • Derailment of Freight Train 4DA2 Near Cadney Park, South Australia
    Australian Transport Safety Bureau ATSB TRANSPORT SAFETY REPORT (ATSB) is an independent Rail Occurrence Investigation RO-2010-012 Commonwealth Government statutory Agency. The Bureau is governed by a Final Commission and is entirely separate from transport regulators, policy makers and service providers. The ATSB's function is to improve safety and public confidence in the aviation, Derailment of freight train 4DA2 marine and rail modes of transport through excellence in: • independent investigation of transport accidents and other near Cadney Park, South Australia safety occurrences • safety data recording, analysis and research • fostering safety awareness, 25 November 2010 knowledge and action. The ATSB does not investigate for the Figure 1: Derailment site looking towards Adelaide purpose of apportioning blame or to provide a means for determining liability. The ATSB performs its functions in accordance with the provisions of the Transport Safety Investigation Act 2003 and, where applicable, relevant international agreements. When the ATSB issues a safety recommendation, the person, organisation or agency must provide a written response within 90 days. That response must indicate whether the person, organisation or agency accepts the recommendation, any reasons for not accepting part or all of the recommendation, and details of any proposed safety action to give effect to the recommendation. © Commonwealth of Australia 2011 In the interests of enhancing the value of the information contained in this publication you may download, print, reproduce and distribute this material acknowledging the Australian Transport Safety Bureau as the source. However, copyright in the Direction of material obtained from other agencies, train travel private individuals or organisations, belongs to those agencies, individuals or organisations.
    [Show full text]
  • But Why: a Podcast for Curious Kids Are There Underground Cities
    But Why: A Podcast for Curious Kids Are There Underground Cities? January 5, 2018 [00:00:20] This is [00:00:21] But Why: A Podcast For Curious Kids from Vermont Public Radio. On this show we take your questions on anything from science to art to history to ethics. And we find interesting people to help answer them. [00:00:37] Sometimes we answer them ourselves and sometimes we get to go on field trips to answer your questions. That's my favorite. I'll tell you how to ask your own question at the end of the episode. I am actually outside right now and I am not going to stay outside for very long. I am in Montreal, in Canada, and it is minus 5 degrees out. That's Fahrenheit. If you live here in Canada you'd say it's minus 20 Celsius. I am freezing. My toes are froze. This is the kind of weather that freezes the little hairs inside your nostrils. So I'm going to go inside but that's perfect because that's where we need to go [00:01:22] to answer today's question. My name is Wyatt and I live Los Angeles. And I am five years old. [00:01:32] I want to know if there is underground cities? Well it just so happens I am standing outside a sign that says "Reseau" which in Montreal represents the underground city. Let's go in. [00:01:49] Okay. I am now inside the McGill metro station. But this is more than a subway or a tube stop.
    [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]