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Neil Phillips
University of Melbourne, Stellenbosch University (RSA), Phillipsgold P/L
21 March 2018
Nibbles : 6.30pm
Presentation: 6.50pm (approx.)
Basement on View
50 View St, Bendigo VIC 3550
Neil Phillips is an honorary professor at the University of Melbourne and at Stellenbosch University in South Africa, and has been co-leading the Melbourne Geology of GOLD course since 1996. He was the editor of the 2017 Australian Ore Deposit monograph. This GPIC presentation in Bendigo combines his on-going research on gold and mapping of Victorian granites
Undergraduate teaching of granite intrusions says that they have gently-curving, vertical sides and plunge deep into the Crust; this concept is borne out on published maps. A contrary view is proposed by Cruden, Clemens and others who suggest that granite intrusions might be sheet-like and close to horizontal. They cite classic examples from the Himalayas and Andes where there is extreme vertical exposure, but convincing field examples from SE Australia have been lacking.The Strathbogie granite was intruded at 372 My and dominates 2000 km-2 of central Victoria. Across the batholith, the boundary of granite with Siluro-Devonian hornfels varies from 150m to 930m asl, and it varies 450m on single hillsides. Furthermore, the boundary can be mapped to better than 10m accuracy for much of the southern edge. Mapping with the advantage of this topography revises the published remotely-sensed boundary by several hundred metres. The net result is an accurate boundary trace across the topography that indicates a complex geometry of straight sections, right angle corners, steep and shallow dips, inward and outward dips, but no uniform gently-curving, near-vertical margins. The Tallarook plateau at the far SW end of the Strathbogie batholith illustrates all these boundary varieties in its 60km of mapped contact. Many parts are quite accessible and documented in the new Tallarook Guide
Australian Ore Deposit monograph: hard copies and USBs of this volume will be available at the GPIC meeting [and you will save postage]. If you want to ensure your copy then advise Eliza Sannerman at the AusIMM esannerman@ausimm.com.au or Brendan Rodway brodway@ausimm.com.au well beforehand and copies will be set aside for you. (AOD Order Form 2018)
To support our Victorian Branch and ongoing future events we kindly ask for a small admission fee from our attendees:
AIG & AusIMM Members $10
Non-Members $15
Students Free
AIG Victoria will supply refreshments and nibblies.
Rodney Boucher rodney@linex.com.au
