EPR spectra and lithogeochemistry of jasperoids at Carlin, Nevada: distinction between auriferous and barren rocks

The acid insoluble residue of twenty-nine gold-bearing and ten barren jasperoids from Carlin, Nevada, were analysed by electron paramagnetic resonance powder spectroscopy (EPR), and by simultaneous proton-induced X-ray emission (PIXE) and proton-induced gamma ray emission (PIGME) spectroscopy. The mineralised samples are characterised by high Li, F, AI, K, Ti, Rb, V, Y, and Zr values in general and by significantly higher Rb/Al and V/Al ratios in particular. The chemical differences are largely caused by the abundance and type of sericite present. Significant differences in EPR intensity exist between the mineralised and barren jasperoids. © 1995.