ГЕОХИМИЧЕСКИЕ ОСОБЕННОСТИ И ПАЛЕОГЕОДИНАМИЧЕСКИЕ ОБСТАНОВКИ НАКОПЛЕНИЯ ПЕРМСКИХ И ТРИАСОВЫХ ОТЛОЖЕНИЙ ЮГА ЛАОЕЛИН-ГРОДЕКОВСКОГО ТЕРРЕЙНА (ПРИМОРЬЕ)

Abstract

New geochemical data on the Late Paleozoic and Early Mesozoic sandy rocks of the southern part of the Laoeling-Grodekovo terrane of the South-Western Primorye are presented. It is shown that terrane deposits differ significantly in geochemical parameters: sandstones of the Barabash and Mangugai formations most closely correspond to the graywackes, those of the Kazachka formation to the lithite arenites, and those of the Reshetnikovka formation to arkoses. The rocks are characterized by a rather high degree of maturity of the terrigenous material and contain mainly fragments of acidic igneous rocks in the clastic part. The geochemical data obtained were generalized and interpreted based on their comparison with the compositions of modern sediments and ancient deposits accumulated in the known geodynamic settings. The results of the studies, in general, suggest the formation of terrane deposits in a basin associated with the setting of transform slip of lithospheric plates. The main source of detrital material was eroded acid igneous rocks, to which a small fraction of products of disintegration of basic-middle volcanics and sedimentary rocks enriched in ancient components was added.