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Minerals Division North Pilbara, AGSO Record 2001/10 Gold Deposits of the Pilbara Craton: Results of AGSO Research, 1998-2000 David Huston, Richard Blewett, Terrence Mernaugh, Shen-Su Sun and Julienne Kamprad AGSO GEOSCIENCE AUSTRALIA ~ www.agso.gov.au~ AGSO – GEOSCIENCE AUSTRALIA Chief Executive Officer: Neil Williams Copyright Commonwealth of Australia 2001 This work is copyright. Apart from any fair dealings for the purposes of study, research, criticism or review, as permitted under the Copyright Act, no part may be reproduced by any process without written permission. Inquiries should be directed to the Communications Unit, AGSO – Geoscience Australia, GPO Box 378, Canberra City, ACT, 2601. ISSN 1039–0073 ISBN 0 642 39888 7 Bibliographic reference: David Huston, Richard Blewett, Terrence Mernagh, Shen-Su Sun and Julienne Kamprad 2001. Gold Deposits of the Pilbara Craton: Results of AGSO Research, 1998- 2000. AGSO – Geoscience Australia, Record 2001/10. AGSO – Geoscience Australia has tried to make the information in this product as accurate as possible. However, it does not guarantee that the information is totally accurate or complete. THEREFORE YOU SHOULD NOT RELY SOLELY ON THIS INFORMATION WHEN MAKING A COMMERCIAL DECISION. Table of Contents INTRODUCTION .............................................................................................................................................................1 ANALYTICAL TECHNIQUES.......................................................................................................................................1 THE GEOLOGY AND STRUCTURE OF THE NORTH PILBARA TERRANE......................................................2 SUPRACRUSTAL ROCKS....................................................................................................................................................2 GRANITOID COMPLEXES ..................................................................................................................................................3 REGIONAL STRUCTURAL GEOLOGY.................................................................................................................................3 AN OVERVIEW OF GOLD MINERALISATION IN THE PILBARA ......................................................................4 TIMING OF MINERALISATION............................................................................................................................................4 LODE AU AND SB-AU DEPOSITS OF THE INDEE DISTRICT ..............................................................................6 STRUCTURAL GEOLOGY ..................................................................................................................................................6 aD deformation.........................................................................................................................................................6 1 aD2 deformation.........................................................................................................................................................7 aD deformation.........................................................................................................................................................7 3 Extension....................................................................................................................................................................7 aD deformation.........................................................................................................................................................7 4 Faults .........................................................................................................................................................................7 SELECTED DEPOSITS OF THE INDEE DISTRICT ...................................................................................................................7 The Withnell deposit...................................................................................................................................................7 Structural geology.....................................................................................................................................................................8 Veining, mineralisation and alteration......................................................................................................................................8 Fluid inclusion studies. .............................................................................................................................................................8 The Camel deposits ....................................................................................................................................................9 Antimony-gold deposits..............................................................................................................................................9 Fluid inclusion studies ..............................................................................................................................................................9 Other lode gold deposits ..........................................................................................................................................10 EPITHERMAL VEIN DEPOSITS IN THE CENTRAL PILBARA TECTONIC ZONE ........................................10 BECHER PROSPECT.........................................................................................................................................................11 Fluid inclusion studies. ............................................................................................................................................11 ORANGE ROCK PROSPECT..............................................................................................................................................11 VEINS IN THE OPALINE WELL GRANITE.........................................................................................................................12 Fluid inclusion studies. ............................................................................................................................................12 THE SAMS RIDGE VEIN SYSTEM .....................................................................................................................................12 GEOCHEMISTRY OF THE HIGH LEVEL VEINS ...................................................................................................................13 THE MT YORK-LYNAS FIND DISTRICT.................................................................................................................13 REGIONAL GEOLOGY .....................................................................................................................................................13 STRUCTURAL GEOLOGY ................................................................................................................................................14 MINERALISATION...........................................................................................................................................................14 Zakanaka South deposit. ..........................................................................................................................................14 McPhees North deposit ............................................................................................................................................15 Birthday Gift deposit................................................................................................................................................15 Lynas Find Pb-fluorite deposit.................................................................................................................................15 LODE GOLD DEPOSITS FROM THE WARRAWOONA DISTRICT....................................................................15 STRUCTURAL GEOLOGY ................................................................................................................................................16 FLUID INCLUSIONS .........................................................................................................................................................17 Microthermometry....................................................................................................................................................17 Raman microprobe analysis.....................................................................................................................................17 Discussion ................................................................................................................................................................17 SELECTED DEPOSITS OF THE WARRAWOONA DISTRICT ..................................................................................................18 AGE OF MINERALISATION ..............................................................................................................................................18 LODE GOLD DEPOSITS OF THE SOUTHWEST MOSQUITO CREEK BELT ..................................................18 INTRODUCTION ..............................................................................................................................................................18 REGIONAL GEOLOGY.....................................................................................................................................................19
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