Trace element quantification in gold as a means of distinguishing the genesis of placer gold

Abstract

Analyses of placer gold has largely been restricted to the major components, Au, Ag, Cu, Hg from electron microprobe analysis (EMPA) due to the relatively high detection limits for other minor elements. LA-ICP-MS has sub-ppm detection limits for most elements in gold, but by comparison with EMPA is both destructive and penetrates the gold to much greater in depth. We have analysed gold grains for a suite of elements to assess which are present in sufficient concentration to form a basis for the discrimination of gold from different localities and different styles of mineralization. High resolution multi element maps of selected grains, analysed by icpTOF-MS, reveal some elements are controlled by crystal structure, grain boundaries or random events.