These deposits are characterized by invisible (typically microscopic and/or dissolved) gold in arsenic rich pyrite and arsenopyrite.
The Carlin type deposits show enrichment in the elements gold, arsenic, antimony, mercury, thallium and barium.
[5] During the Eocene, fluids flowed through the lower plate of thrust faults and the underlying fractured carbonates.
A low Ph in the fluids allowed for a significant amount of carbonate rocks to dissolve.
Later, when the Basin and Range began its extension, normal faulting took place, and the ore deposits were downfaulted and buried under alluvial sediment.