Alluvial gold is an ideal exploration tracer to bedrock source and indicator of bedrock mineralisation style because (i) gold
occurs in a wide range of deposit types, (ii) primary composition is sensitive to style of mineralisation, and (iii) it is a
heavy resistate mineral that is readily preserved and easily sampled. In regional exploration of the Central Ranges of Irian
Jaya, alluvial gold mineralogy has been applied to maximise the information return from panned concentrate sampling and
to focus exploration effort. Primary gold is a solid solution of Au+AgCuHg, trace Pd, Te, and Sb. In general AgHg
increase and Cu decreases with inferred decreasing temperature of formation, and gold from particular mineralisation
styles has signature compositions that can be used as indicators of bedrock mineralisation type. Furthermore, the
abundance of alluvial gold is an indicator of the economic potential of a catchment. The convergent continental-oceanic
plate geology of the Central Ranges is conducive to a wide range of mineralisation styles. Mineralogy of gold in ophiolite,
skarn, porphyry, mesothermal vein and possible VHMS environments is characterised from alluvial and bedrock samples,
and the use of gold mineralogy in prospecting at regional scale through prospect definition to drilling is demonstrated.