GEOCHEMISTRY AND PROTOLITHS OF THE METABASITE-ENDERBITE ASSOCIATION OF THE DZHUGDZHUR BLOCK, ALDAN SHIELD

Abstract

The bottom of the stratigraphic sequence of the Dzhugdzhur deep-seated granulite complex was determined to consist of a stratified metabasite-enderbite association. The distributions of major and trace elements indicate that the protoliths of the association were volcanic rocks of the calc-alkaline, komatiite-tholeiite, and picrite series. The model assumed for the genesis of the protolithic volcanics of the metabasite-enderbite association includes two stages. The first of them was responsible for the decompression-induced partial melting of the material of an ascending mantle plume with the derivation of melts of the komatiite-tholeiite series. During the second stage, the volcanics of the calc-alkaline series were produced by the partial melting of the metabasite crust under the effect of the heat of the ascending mantle plume. The protoliths of the metabasite-enderbite association were formed in the Early Proterozoic. © Pleiades Publishing, Ltd. 2007.