Lower Silurian deposits of South - Western Primorye: composition and origin

The authors present the results of studying the material composition of terrigenous rocks at the early Silurian Cordonkà formation of the South-Western Primorye. In terms of their parameters, the rocks correspond to petrogenic graywackes formed due to mechanical destruction of rocks of demolition sources. They are characterized by a low degree of the material maturity, weak processing of it, high burial speed. Interpretation of the results showed that sediments accumulated in the basin associated with the oceanic island arc. The sources area was the arc itself, composed of the basic and intermediate volcanic rocks, as well as the igneous and sedimentary formations of its basement.