黑龙江二克山及其邻区富钾火山岩系的地球化学探讨

基于12个微量元素、10个稀土元素和24个同位素分析结果,作者认为本区钾质火山岩系中超基性岩和极大多数基性岩有接近原生岩浆的成分,岩浆都是地幔岩石低程度部分熔融形成的,其源岩成分为受流体交代的金云母石榴石二辉橄榄岩。综地球化学、地球物理及地质三方面资料分析,论证本区火山活动的构造背景是大陆裂谷。

DISCUSSION ON GEOCHEMISTRY OF K-RICH VOLCANIC ROCKS SERIES FROM ERKESHAN AND ITS NEIGHBOURINA AREA,HEILONGJIANG PROVENCE

Cenozoic K-rick volcanics of Erkeshan, Wudalianchi and Keluo areas in Heilongjiang province are ultrabasic-basic volcanic rocks rare in the world, They consist of three volcanic groups in Erekeshan, Wuaalianchi and Keluo,Analyses of 12 trace elements, 10 REE and 21 isotopes of the volcanic rocks show that the K -rich volcanic rocks in this area are slightly differentiated and evolved, and have the composition near to primary magma The author suggests that magmas in this area having very low pb isotope ratios should be reslted from the magmas assimilating the low Pb rocks above it, which still belonged to. upper mantle. According to the geochemical characters of the volcanic rocks the author discusses the source rocks of the magma and believes its source rocks are phlogopite garnet Iherzolite matasomatized by the fluids from deeper mantle, which are rich in LREE and incompatible elements.Further, based on geochemical data and so on , the author analysises the tectonic setting, and suggesses that it be contintal rift.