The relation between ore‐deposit formation and subduction: Mass balance considerations

Abstract

Mass balance calculations indicate that the potential supply of metals resulting from subduction of oceanic crust and sediment far exceeds that required for mineralization in island arcs. Subduction of oceanic crust is more important than that of sediment in supplying these metals and the subduction of manganese nodules makes only a negligible contribution. The nature and extent of mineralization in island arcs therefore depend on the nature, geometry and rate of subduction. In the Pacific, two types of subduction system occur: the high-stress (Chilean) type, characterized by shallow subduction and the formation of porphyry copper deposits in andesitic arcs, and the low-stress (Mariana) type, characterized by deep subduction and the formation of Kuroko deposits in the back-arc basin, and porphyry copper and epithermal gold deposits in the island arc. Kuroko deposits are analogous to the epithermal deposits but are formed from saline hydrothermal fluids under much higher hydrostatic pressure.

Magmatic–Hydrothermal Transport of Metals at Arc Plutonic Roots: Insights from the Ildeus Mafic–Ultramafic Complex, Stanovoy Suture Zone (Russian Far East)

“…However, the exact modes of metal transport in subduction zone environments are still subject to vigorous scientific debate. The predominant paradigm suggests that ore metals are preferably transported by dense hydrous fluids associated with magma movement between a range of mantle and crustal geochemical reservoirs [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. Most siderophile and chalcophile elements eagerly partition into an aqueous fluid phase, especially in the presence of sulfur and halogens [27][28][29][30][31][32][33][34][35][36][37][38].…”