The ICP is centered within the Idaho Cobalt Belt – a unique example of sea-floor hydrothermal brines that vented along an ancient rift within a deep-water setting, providing for an interesting and distinctive geochemistry. The Idaho Cobalt Belt is a northwest-trending zone of Co-Cu-Au occurrences, at least 64 km long and up to 10 km wide. It is an exceptional metallogenic province in which cobalt occurs in sufficiently high concentrations to make it the primary metal in the deposits.
The deposits are mostly strata-bound and appear to have formed during a mafic volcanogenic-exhalative mineralizing event on a paleo-sea-floor ca1600 million years ago. More recent regional metamorphic events have remobilized Cu and, to a lesser extent, Co in varying degrees throughout the belt. The deposits are unusually rich in Co, Cu, Fe, As, Au, B, Bi and light rare earths, but low in Ni (relative to Co), Ag, Pb, and Zn. The synsedimentary controls, mineralogy and geochemistry are unusual among ore deposits, though similar features in some other deposits are known. Sediment-hosted deposits are major ore producers in the world, but unlike the Idaho Cobalt Belt, most tend to be Pb and Zn rich.Some sediment-hosted deposits that contain Cu also contain Co - notably, the deposits of the Katanga province of the Democratic Republic of the Congo and the adjoining Zambian Copperbelt deposits. Significant differences exist between deposits in West Africa and the Idaho Cobalt Belt, whereas many intriguing similarities are found between Idaho Cobalt Beltdeposits and Sullivan, Canada, and Mount Isa and Broken Hill, Australia.
The Idaho Cobalt Beltis currently known to host several Co-Cu deposits within various sequences of metamorphosed, mafic volcanoclastic rocks.
Mineralization at the ICP is closely associated with the mafic sequences of the middle unit of the Apple Creek Formation. Dominant ore minerals include cobaltite (CoAsS) and chalcopyrite (CuFeS2), with lesser, variable occurrences of gold. Other minerals present in small quantities are pyrite (FeS2), pyrrhotite (FeS), arsenopyrite (FeAsS), linnaeite ((Co Ni)3S4), loellingite (FeAs2), safflorite (CoFeAs2), enargite (Cu3AsS4) and marcasite (FeS2).