地质通报Issue(9)：1284-1292,9.
内蒙古西乌旗地区大石寨组火山岩时代及地球化学特征
Age and geochemical characteristics of the Dashizai Formation vol-canic rocks in Xi Ujimqin Banner, Inner Mongolia
摘要
Abstract
The Dashizai Formation volcanic rocks in Xi Ujimqin Banner area consist mainly of rhyolite. LA-ICP-MS zircon U-Pb dating and whole-rock major, trace and rare earth elements analyses show that the age of the rhyolite in this area is 280.3Ma±1.4Ma, implying early Permian. Dashizhai volcanic rocks belong to high potassium peraluminous calc-alkaline volcanic rocks, and the con-tent of SiO2, K2O and Al2O3 is high. Chondrite-normalized REE patterns are generally right-oblique with the enrichment of the LREE, Eu exhibits negative anomalies, there exists no significant loss of HREE, Rb, Th, U, K and other LILE elements show signifi-cant enrichment, Ba exhibits weak losses, HFSE exhibit obvious Ta, Sr, P and Ti losses, and Zr, Hf shows relative enrichment. It is held that the rhyolite of this area was probably formed by fractional crystallization of basalt, andesite and other basic volcanic rocks, and the tectonic environment for the formation of the rhyolite in this area was continental marginal arc.关键词
流纹岩/锆石U-Pb年龄/岩石地球化学/西乌旗地区Key words
rhyolite/zircon U-Pb age/petrochemistry/Xi Ujimqin Banner area分类
天文与地球科学引用本文复制引用
樊航宇,李明辰,张全,黄猛,张晓飞,李继军..内蒙古西乌旗地区大石寨组火山岩时代及地球化学特征[J].地质通报,2014,(9):1284-1292,9.基金项目
中国地质调查局项目 （）
