Geology, magmatism, metallogeny, and geodynamics of the South Kuril islands

Abstract

Intense fluid thermal fluxes in the continental lithosphere and crust from sub- and supra-subduction asthenospheric zones were the root cause of the formation of magmatic chambers and the development of volcanism and multimetal ores. We demonstrate this phenomenon using the example of the South Kuril. The southern chain (including the large Kunashir, Iturup, and Urup islands) of the Greater Kuril Ridge of the “island arc-trench” system is confined to the northwestern Pacific subduction megazone. Inherited transform faults (Nosappu, Iturup, and Urup) occur in the oceanward part of the SSE segment of the Kuril-Kamchatka trench. Repeated movements of the oceanic region sandwiched between the fault zones were accompanied by earthquakes and low-volume petit-spot-type submarine eruptions of highly alkaline basaltic rocks. The latter were sourced from an asthenospheric mantle beneath the oceanic slab. Recurrent manifestations of compressional to extensional stresses in the subduction zone during the Oligocene-Neogene and Pleistocene-Holocene were accompanied by under and overthrusting and earthquakes.