RDM ahead of BHP in Nullarbor, page-2

Most probably have seen this. It is off RDMs website, it may be of interest to everyone except cash hound.

Oct 26th, 2015
Drilling of the basement under the Nullarbor Plain has revealed a wide expanse of oceanic crust, and remnants of primitive arc and rift-related magmatic rocks, defying all predictions about the nature of our continent between the Yilgarn and Gawler Cratons.
The remarkable discovery was announced last month by the Geological Survey of Western Australia at a workshop on the results of its eight-hole, Exploration Incentive Scheme (EIS) stratigraphic drilling program, conducted in 2013 and 2014.
The drilling was designed to investigate the greenfield Madura and Coompana provinces that
are overlain by up to 500 metres of cover rocks in the Bight and Eucla Basins.
The results have put to rest any hopes of a repetition of the Albany-Fraser Orogen further east under cover. But explorers have new reasons to be excited, including the potential for exhalative and VMS deposits, and giant copper-gold deposits like those in the Pacific Rim. Another exciting aspect of the drill results was the intersection of sulphides in every hole in the program, despite the fact GSWA was not aiming for economic targets.
GSWA’s manager for the Albany-Fraser project, Catherine Spaggiari, told
Greenfieldexplorer it was encouraging to encounter sulphides over such a large geographic area, and in most of the rock types of different ages encountered by the drilling. “The presence of anomalous copper is also encouraging, and it’s possible that we may be seeing signs of a number of mineral systems.

Catherine Spaggiari, GSWA Project Manager, Albany-Fraser Orogen
She said the surprising results highlighted the importance of going under the deep cover to see what’s there. “We still have large tracts of buried geology in Australia that comprise missing links in our understanding of the exposed regions. These under-cover regions are where big unknown deposits might be hiding, so it is important that we learn how to efficiently explore for them. The more we understand what we might be looking for, what the geology is, the better we can apply modern exploration techniques.”
Catherine said the presence of such a large tract of oceanic and oceanic arc crust was significant because it was rare for a large, relatively intact piece of this type of crust to be preserved. “We would argue that it’s essentially an ophiolite. Ancient oceanic crust tends to be preserved only as ophiolites, as most oceanic crust gets subducted. This preservation means that, if there are any ore deposits within that crust, they would also probably be preserved.” The discovery of preserved oceanic and oceanic arc crust created potential for a wide variety of deposit styles, including exhalative, VMS, and subduction- or arc-related Ni-PGE deposits. “We see potential for these styles in the Madura Province, while further west in the Forrest Zone, rift-related tectonics at about 1500 Ma have produced a high-K suite of volcanics and granites formed from melting alkali-metasomatised, subduction-related crust. This suggests potential for VMS or IOCG in the Forrest Zone.”
She said the discovery of a belt of shoshonitic rocks aged about 1180 Ma in the northern Forrest Zone also created potential for another major style of orebody. “Shoshonites are well known to have potential for Cu-Au, and the Forrest Zone shoshonites show close compositional similarities with Cu-Au mineralised shoshonites in the Early Silurian Macquarie Arc in NSW.”
Catherine said the stratigraphic drilling added significantly to our understanding of the basement under the Nullarbor, but there was still much to learn.
She said explorers could focus on what’s there, rather than try to look for correlations with other regions or other deposits. “If you narrow your ideas, you might miss something. Having said that, we think it is worth looking for Nova-style mineralisation in the eastern Nornalup Zone of the Albany-Fraser Orogen, which is partly under the edge of the Nullarbor, but the cover is shallower.”
Catherine added that the stratigraphic drilling program had not only taught us about the basement geology, but how best to approach exploring and drilling in the Nullarbor region. “We encourage people to contact us regarding this, and to apply for EIS co-funded drilling grants. While we understand the costs and risk of exploring there, particularly in the current climate, GSWA is keen to see further work in this region and where possible, will provide information and assistance.”