Prospectivity Analysis of the Lachlan Fold Belt, New South Wales
The Lachlan Fold Belt is a structural unit that forms the southeastern part of the Tasmanides in New South Wales, Australia. It is a Middle Paleozoic accretionary orogen and hosts one of the world's major gold provinces. The first major discovery of gold was in 1851 at the Ophir Gold Diggings. Later discoveries used geophysical surveys and deep drilling methods such as those at the Cobar and East Cadia mine sites.
Kenex has now completed GIS and mineral prospectivity models for porphyry, skarn, orogenic and VMS mineralisation styles within the LFB.
Predictive maps have been developed that map source, transport, trap and metal deposition mechanisms for the four types of mineralisation. The spatial analysis used geophysics data, geochemistry data of rock, drill hole and stream samples, and detailed lithology and structural data. For each mineralisation style, different geological parameters were identified as important for predicting gold mineralisation, including:
- Porphyry: proximity to felsic to intermediate intrusive and extrusive lithologies; Au, Ag and Cu geochemistry of drill holes and rock chips; proximity to high magnetic gradient.
- Skarn: proximity to Paleozoic calcareous lithology; N-S trending faults; proximity to areas of high competency contrast.
- Orogenic: proximity to Paleozoic clastic sediments; correlation with fault splays and intersections; proximity to magnetic lows.
- VMS: correlation with density of faults; proximity to synvolcanic lithologies; Ag, As, Bi, Cu, Zn geochemistry of host rocks.
Using weights of evidence techniques, prospectivity maps were produced that assessed the probability of finding mineral deposits based on input predictive maps that represent all stages of the relevant mineral system model.
These prospectivity maps and exploration GIS would be a valuable tool for your company to accelerate exploration if you already hold tenements, or to get ahead of your competitors if you want to identify potential opportunities in NSW's most productive goldfield. Moreover, models can be tailored to your needs using your prospect scale exploration data to prioritise targets within your tenement portfolio.