Hello all,
I wondered if the chargeability shown on the survey could potentially be Pyrite (fools gold). I asked a geo I know and this is his reply. In summary, he said the proof will be in the drill. He also asked if their was any record of Pyrite in the area - I thought I read on this board somewhere that no pyrite has been found in this area (though I could be wrong on that).
Chargeability is the ability of the subsurface to act as a capacitor. Any highly conductive material inter bound by more resistive material will enable the accumulation of positive and negative charges within the conductive material and kept separated by the more resistive material. This separation of charge creates and voltage potential. Because the subsurface is not a perfect insulator or conductor, this charge will gradually dissipate. IP chargeability is measuring how the voltage potential decays with time after electricity is injected in to the subsurface. The more the conductive the material, the larger the amount of charge that can be built up and therefore the longer the decay time. Unfortunately, like all geophysics this method is plagued by the ambiguity problem. Multiple subsurface scenarios/materials can result in identical measured parameters. Meaning that gold interbound by more resistive materials could create these anomalies, however other conductive materials could also yield very similar results. I can’t remember if Pyrite is conductive, one of the rock hound witch doctors will have to pipe up on that one. If you’re lucky gold may have a unique band of IP chargeability that are different from the band of IP chargeabilities making the differentiation of the two easier. Unfortunately, they will likely overlap and lead you back to the ambiguity problem. The only sure fire way to get around this is to use another geophysical method that measures a physical property that differs between gold and pyrite or if this property is not known, utilize a few different geophysical methods that are unrelated.
Simply put, if Pyrite is highly conductive, it could very well produce the same hot spots. The only reality is ground truthing.