GENESIS AND EMPLACEMENT MECHANISM OF THE LATE TRIASSIC ADAMELLITE SERIES IN YICHUN AREA,HEILONGJIANG PROVINCE

The Late Triassic adamellite masses in the Yichun-Yanshou granite zone are a series of rocks with complete texture evolution. According to their textures, the rocks can be divided into types of first stage, second stage and last stage textures. The homoeogene diorite enclaves are broadly developed in the adamellite masses. The rocks show obvious characteristics of Ⅰ-type granite in petrology, petrochemistry and geochemistry. Analysis on the occurring tectonic setting indicates that the granites were generated in the post-collision environment, and the post-orogenic extension system is the main condition for the forming of the granite. The magma emplacement mechanism shows passive characteristics.