Gold in organic matter, Maldon, Victoria, Australia

Submicroscopic mixtures of metallic gold and solid hydrocarbons form aggreg ates of up to 100 mu m in fractures and vugs in loellingite from gold-rich samples from Maldon, Australia. Electron microprobe analyses show that soli d hydrocarbons contain about 1 wt percent S and Fe, up to 3 wt percent O, a nd several wt percent Au. Infrared microscopy indicates that the solid hydr ocarbons comprise mainly conjugated benzene rings with short-chain function al groups composed of carbonyl, groups (C=O), CH3, CH2, and OH. Metals (Fe and Au) are suggested to be bound to aryl ketones, or may be bound to hydro carbons by S-functional groups. It is proposed that metal-bearing solid hyd rocarbons are replaced by siderite, producing spectacular nebular inclusion s of minute gold grains in replacive carbonate forming veinlets in the host quartz.