Kema terrane: A fragment of a back-arc basin of the early Cretaceous Moneron-Samarga island-arc system, East Sikhote-Alin range, Russian Far East

摘要

The Kema terrane is a suite of Barremian(?)-Aptian to Albian volcano-sedimentary rocks of Sikhote-Alin that are interpreted as deposits of the back-arc basin of the Moneron-Samarga island-arc system. Compositional features of the different-type deposits indicate a near-slope depositional environment influenced by volcanic processes. Studies of slump fold orientation testify to the accumulation of material from southeast to northwest by gravitational sliding. Compositional characteristics of terrigenous rocks suggest the major provenance for detrital material was an ensialic volcanic island arc. Petrochemical characteristics of basaltic rocks indicate that the formations studied were confined to the back part of the arc.