CLASTIC HEAVY MINERAL ASSEMBLAGES IN PERMIAN-MESOZOIC ACCRETIONARY CHERTY AND SILICEOUS-CLAYEY COMPLEXES OF SIKHOTE ALIN

Abstract

The paper presents results of the study of assemblages of clastic heavy minerals and geochemical features of some assemblages in several Permian-Mesozoic cherty and siliceous-clayey sequences of Sikhote Alin. They are composed of pelagic and hemipelagic sediments of the Panthalassa (Paleopacific) Ocean. Four typical mineral assemblages and their environments are established. In one of the ocean segments, where sedimentary cover formed during the Late Paleozoic-Early Cretaceous, the Permian pelagic domain was characterized by the amphibole-pyroxene assemblage with heavy minerals derived from ophiolites. The Triassic-Jurassic stage was marked by development of the clinopyroxene assemblage with heavy minerals derived from intraplate alkaline volcanic complexes. Middle-Late Jurassic hemipelagic sediments host the zircon-clinopyroxene assemblage with a greater role of continental environments and the presence of volcanic products of the convergence zone. Another segment of the ocean accumulated red cherts and siliceous-clayey sediments during the Jurassic-Early Cretaceous under the influence of island-arc volcanism. © Pleiades Publishing, Inc. 2006.