The western Pilbara region south of Karratha has been a focus for gold explorers thanks to the emergence of “watermelon seed” shaped coarse gold nuggets found at or near surface.

The gold is typically located in the Archean rocks of the Pilbara around what is considered to be the unconformity between Mesoarchean Western Pilbara basement and overlying Neoarchean Fortescue Group rocks.

The CSIRO study will focus on answering questions such as:

• What lithology or litholigies host the gold deposits?
• What is the sedimentological setting of these units?
• What is the relationship between host units, gold mineralisation and igneous intrusions or extrusives?
• What is the background mineralogy and geochemistry of the host rocks?
• What is the alteration mineralogy associated with gold mineralisation? and 
• What evidence is there of high temperature versus low temperature microstructures in the gold nuggets.

The CSIRO team will be primarily composed of mineralogy and microstructures expert Dr Mark Pearce, geochemist Dr Alistair White, hyperspectral geologist Dr Carsten Laukamp, and sedimentologist Dr Sam Spinks.

Support from other CSIRO staff with experience in igneous geochemistry, economic geology and regional geology will be on hand as required.

Artimis executive director and head of exploration Ed Mead said it was important Artemis engaged with independent leading industry specialists to seek a deeper understanding as to why the gold existing in the conglomerates south of Karratha and how these unique “watermelon seed” nuggets were formed.