SOUTHWEST PACIFIC EPITHERMAL GOLD - A ROCK-GEOCHEMISTRY PERSPECTIVE

The bedrock geochemical response to epithermal gold mineralization has implications for genetic modelling and secondary media exploration, as well as for rock-geochemistry exploration programmes. Although there is little documentation of the geochemical signatures of these deposits for the Southwest Pacific, combining the limited data with results from studies of North American epithermal precious-metal deposits and Southwest Pacific active geothermal systems can generate sufficient information for empirical modelling. Rock-geochemistry data support the genetic analogy between geothermal fields and epithermal deposits. The known lateral extent of geothermal fields indicates that geochemical haloes of epithermal deposits may be extensive, thus representing significant exploration targets. Recent studies of a number of Southwest Pacific deposits support this expectation. Rock-geochemical responses are considered to be an indispensible aid in designing stream-sediment and soil-geochemical surveys for Southwest Pacific epithermal gold deposits. No single element, except possibly Au itself, is a definitive indicator, and a multi-element approach reduces the possibility of erroneous interpretation. © 1990.