GEOCHEMICAL FEATURES OF THE VOLCANIC ROCKS OF LINZIZONG GROUP IN CHUOQIN BASIN

Violent volcanic eruption occurred in the Chuoqin Basin of Qinghai-Tibetan Plateau during Cenozoic era, resulting in volcanic rocks consisting of andesite, rhyolite, intemediate-acid lava flow and pyroclastics known as the Linzizong Group which are distributed mainly in the Gangdise tectono-volcanic belt of the central uplift in the Chuoqin Basin but sparsely scattered in the north depression. Petrochemical study suggests the volcanics are of calc-alkalic to high potassium calc-alkalic suite; Geochemical study indicates that they are akin to the island are type formed by collision of the Himalayian plate with the Gangdis-Nianqing Tangula plate.