Precambrian volcanic-associated massive sulfide deposits

Phanerozoic volcanic-associated massive sulfide deposits (VMSD) were subdivided into the Kuroko, Besshi, Cyprus, and Ural types, which differ in their ore geochemistry and mineralogy, in their composition of volcanic ore-hosting rock associations, and in the proportions of felsic and basaltic volcanics and sedimentary rocks in the volcanic successions. The earliest deposits that can be reliably attributed to the above types originated during the Neoproterozoic during the Pangea supercontinental cycle. Archean and Paleoproterozoic VMSD can be accepted as analogues of these types, resembling them in many respects, although differing from the classic deposits of these types in some characteristics. The formation history of Cyprus-type VMSD is traceable to the Paleoproterozoic when deposits in the Outocumpu area dated at approximately 1970 Ma originated during the early stage of Pangea-I amalgamation, whereas the most ancient Besshi-type deposits 1440 million years old originated during the breakup of that supercontinent. Most of the Neoarchean and Paleoproterozoic VMSD are similar in some of their principal features to those of the Ural and Kuroko types. Deposits of both these types and their ancient analogues evolved in the process of the Earth’s evolution and demonstrated unidirectional changes in their ore composition.