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 algebra Ore algebra In computer algebra, an Ore algebra is a special kind of iterated Ore extension that can be used to represent linear functional operators, including linear differential and/or recurrence operators. The concept is named after Øystein Ore. Let formula_1 be a (commutative) field and formula_2 be a commutative polynomial ring (with formula_3 when formula_4). The iterated skew polynomial ring formula_5 is called an Ore algebra when the formula_6 and formula_7 commute for formula_8, and satisfy formula_9, formula_10 for formula_11. Ore algebras satisfy the Ore condition, and thus can be embedded in a (skew) field of fractions. The constraint of