青藏高原北羌塘新生代高钾钙碱岩系火山岩角闪石类型及痕量元素地球化学

Based on the electron microprobe and laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) analyses, the major and trace element features of amphibole from the Cenozoic high-potassium calc-alkaline dacite of north Qiangtang are discussed in this paper. The result indicates that all of the amphiboles belong to calcic series. Their major elements imply that the dacite should be of crustal origin. And the amphiboles show the Sc, Ti, V, Cr, Co, Ni enrichment and the Th, U, Pb, Rb depletion. Especially, the amphiboles exhibit high content in rare earth element but no remarkable Eu depletion. It may imply that the Cenozoic high-potassium calc-alkaline volcanic rocks from north Qiangtang might be originated from the thickened eclogitic deep crust of Tibetan plateau by dehydration partial melting.