Iron oxide copper gold ore deposits to be within Neoproterozoic to Mesoproterozoic basement. Worldwide, ages of recognised IOCG deposits range from 1.8 Ga to 15 Ma, however, the majority are within the 1.6 Ga to 850 Ma range. Ore minerals in IOCG deposits are typically copper-iron sulfide chalcopyrite and gangue pyrite, forming 10–15% of the rock mass. Supergene profiles can be developed above weathered examples of IOCG deposits, as exemplified by the Sossego deposit, Para State, Brazil, where typical oxidised copper minerals are present, e.g.; malachite, cuprite, native copper and minor amounts of digenite and chalcocite. Alteration is a mixture of sodic-calcic (albite-epidote) to potassic (K-feldspar)
Ore Mountains this is a contract between Boresch of Riesenburg and the Ossegg abbot, Gerwig, in which the division of revenue derived from ore was agreed. Grains of tin ("Zinnkörner" or "Graupen") were obtained at that time in the Seiffen mining area and gave the Bohemian mining town of Graupen (Czech "Krupka") its name. With the further settlement of the Ore Mountains in the 15th century, new, rich, ore deposits were eventually discovered around Schneeberg Annaberg and St. Joachimsthal. The "Second Berggeschrey" started and triggered a massive wave of colonization. In quick succession, new, planned, mining towns were built across the Ore