GSWA Annual Review 1998–99
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GEOLOGICAL SURVEY OF WESTERN AUSTRALIA ANNUAL REVIEW 1998–99 GEOLOGICAL SURVEY OF WESTERN AUSTRALIA GEOLOGICAL SURVEY OF WESTERN AUSTRALIA ANNUAL REVIEW 1998–99 Perth 1999 MINISTER FOR MINES The Hon. Norman Moore, MLA DIRECTOR GENERAL L. C. Ranford DIRECTOR, GEOLOGICAL SURVEY OF WESTERN AUSTRALIA David Blight Coordinating editor: D. P. Reddy Technical papers editor: L. Day The recommended reference for this publication is: (a) For reference to an individual contribution MARTIN, D. McB., THORNE, A. M., and COPP, I. M., 1999, A provisional revised stratigraphy for the Bangemall Group on the EDMUND 1:250 000 sheet: Western Australia Geological Survey, Annual Review 1998–99, p. 51–55. (b) For general reference to the publication GEOLOGICAL SURVEY OF WESTERN AUSTRALIA, 1999, Geological Survey of Western Australia Annual Review 1998–99: Western Australia Geological Survey, 127p. ISBN 0 7309 6660 7 ISSN 1324–504 X The locations of points mentioned in this publication are referenced to the Australian Geodetic Datum 1984 (AGD84) Printed by Quality Press, Perth, Western Australia Cover: Prismatic barite crystals in ferruginous chert, Dresser Formation, from the North Pole area on the NORTH SHAW 1:100 000 sheet, in the northern part of the Pilbara Craton. The barite crystals are approximately 2 cm in length. Frontispiece: Evidence of early life — 3.45 Ga fossil stromatolites from near Marble Bar in the eastern Pilbara region, Western Australia. The surface consists of three-dimensionally preserved conical stromatolites, and was recently presented to the Western Australian Museum for public display (photograph by Tyrone Knights Photography). Contents Contents GSWA mission statement ...................................................... 1 The year in review by David Blight.......................................................................... 3 Selected highlights of mineral and petroleum exploration and development in Western Australia in 1998–99 by D. J. Flint, Gao Mai, P. B. Abeysinghe, D. B. Townsend, and R. H. Bruce ........................................................................ 7 Inside the GSWA................................................................... 26 Staff profiles ....................................................................... 26 Obituary: Joseph Henry Lord, 1919–1999......................... 30 Staff list (30 June 1999) ..................................................... 32 Staff movements (1 July 1998 to 30 June 1999) ............... 34 Organizational chart and key contacts .............................. 35 Technical papers .................................................................. 37 Neoproterozoic successions of the northwestern Officer Basin: a reappraisal by L. Bagas, K. Grey, R. M. Hocking, and I. R. Williams..... 39 High-Mg diorite from the Archaean Pilbara Craton; anorogenic magmas derived from a subduction- modified mantle by R. H. Smithies and D. C. Champion............................... 45 A provisional revised stratigraphy for the Bangemall Group on the EDMUND 1:250 000 sheet by D. McB. Martin, A. M. Thorne, and I. A. Copp ................ 51 v Geological Survey of Western Australia 1998–99 Annual Review The nature of c. 2.0 Ga crust along the southern margin of the Gascoyne Complex by S. Sheppard, S. A. Occhipinti, I. M. Tyler, and D. R. Nelson ................................................................ 56 Geology and alteration of the Merrie greenstone belt by T. R. Farrell and N. G. Adamides ................................... 62 Structural evolution of the Marda–Diemals area, Southern Cross Province by J. E. Greenfield and S. F. Chen...................................... 67 Neoproterozoic glacigene successions, western Officer Basin, Western Australia by K. Grey, S. N. Apak, C. Eyles, N. Eyles, M. K. Stevens, and G. M. Carlsen .............................................................. 73 Program review..................................................................... 81 Appendices ......................................................................... 115 List of acronyms and abbreviations ................................. 117 Planned achievements and publications released .......... 118 External papers published by GSWA staff in 1998–99.... 123 Geological Survey Liaison Committee ............................. 126 vi GSWA mission statement GSWA mission statement Our vision is to make Western Australia the focus of international mineral and petroleum exploration by becoming the benchmark for the delivery of prospectivity-enchancing, high-quality geoscientific products and services that meet the needs of our customers. Our commitment is to provide, in a timely and courteous manner, up to date, quality regional geoscientific data, information, and advice to the mining and petroleum industries, Government, and the public to encourage and support resource exploration and facilitate informed landuse planning and State development. Our role is to elucidate the geological framework of Western Australia and reveal the potential for mineral and petroleum resources by providing spatially related geoscientific information, and regional geological, geophysical, and geochemical map products and reports. These products are based on the acquisition and analysis of field data, including submitted statutory exploration reports. As well, the Geological Survey evaluates mineral and petroleum resources as a basis for decision making by Government, and assists and advises on a variety of community needs, including urban planning and landuse matters. Our strengths are in field-based research, particularly regional geological mapping in both the Precambrian and Phanerozoic provinces of the State. The Survey also has prowess in the fields of structural geology, basin studies, carbonate sedimentology, mineralization studies, geochemistry and regolith studies, geochronology, palaeontology, petrology, and geoscientific computer applications including database compilation. Other areas of expertise include mineral economics, and financial modelling and evaluation of resources projects. As a result of the application of these skills for over 100 years, and of its role as the depository of mineral and exploration reports, the Geological Survey is the custodian of an immense volume of information on the geology of the State and has become the premier pool of geoscientific expertise in Western Australia. 1 Geological Survey of Western Australia 1998–99 Annual Review 2 The year in review The year in review by David Blight For industry-based geologists 1998–99 has been a particularly tough year. Confidence in the ability of explorationists to succeed has been eroded by sentiments fuelled by low commodity prices, particularly gold, perceived problems with the Asian economy, the difficulties of land access associated with the native title process, and the difficulties being experienced by smaller public companies in raising risk capital. Anecdotal evidence suggests that the resultant unemployment amongst geologists is now worse than that experienced at the end of the nickel boom in the early 1970s. There are several risks to Australia associated with this downturn. Apart from the personal issues associated with employment, the country runs a real risk of losing valuable expertise both in the short-term, as geologists seek employment overseas, and in the long-term as geologists pursue alternative employment or business opportunities. Another long-term concern is that because exploration spending is low now, the real effect will impact in 10–15 years, as reserves currently being depleted are not replaced through discovery. While the mining industry is a large direct employer, it also has a significant effect on the general population and the Western Australian economy through a 3.5-times multiplier effect. Furthermore, its impact on the regional communities is far greater than on urban communities. Such employment crises affecting geologists in the exploration industry are thankfully cyclic in nature, and there is no doubt in my mind that employment prospects will improve given time. In the meantime, the Geological Survey of Western Australia (GSWA) has varied its program and plan where possible to provide assistance in these difficult times. It is also pleasing to note the emergence of a self-help group called AGSEAN (Australian Geologist Skills and Employment Advancement Network). This apolitical group has highlighted, to the wider community, the poor state of the industry and the ramifications of unemployment among geoscientists. The Australian Geological Survey Organisation (AGSO) has also suffered during this downturn. Federal funding to this organization has been reduced substantially, resulting in the need to shed approximately 90 positions. The most significant impact of this reduction on Western Australia was cuts to the Minerals Program and, in particular, the commitment to the National Geoscience Mapping Accord (NGMA). Nearly half the staff reductions were associated with the Minerals Program and NGMA activities for 1999–2000 have been put on hold to fund redundancies. The GSWA will endeavour to pick up much of the work not undertaken by AGSO, but will need to do this in the light of its own program and funding issues. Highlights Despite this gloom, I can report that 1998–99 was a productive year for GSWA. We published 28 maps (at various scales), 57 manuscripts, and five digital datasets, including topographical, geological, geophysical, 3 Geological Survey of Western Australia