The Genetic Type and Tectonic Significance of Hongshishan Basic-Ultrabasic Rocks in Beishan, Gansu Province

Basic-ultrabasic rocks of Hongshishan is plate tectonics researchers focus on one of therock.The genetic type and tectonic setting of Hongshishan basic-ultrabasic rocks are discussed by the rock chemistry, trace elements,rareelements.Studies have shown that rock types based on combination of rock,compared with the output relations,segregation dunite body′s development, the internal flow structure rock, late dykes and chromite mineralization of various types of rock should be akinds of intrusions of magma types; from petrochemistry, trace, rareearth element geochemistry of the rock is reflected in the late Paleozoic (Carboniferous-Permian) period and the Paleo-Asian Ocean closed in the south and eliminate the meantime, the birdchildren Mountain-British andesitic island arc developed on the southern marginofarift basin,the type of arc magma mantle product,its mechanism or dynamic environment as a backarc spreading and mantle upwelling of continental rift magmatismmechanism.