内蒙古西伯地区蛇绿-构造混杂岩带岩石学及地球化学特征

Petrology and geochemical characteristics of ophiolite-tectonic melange belt in Xibo area,Inner Mongolia

文章对内蒙古西伯地区蛇绿混杂岩带岩石学、岩石地球化学、微量元素、稀土元素、U-Pb同位素年龄测定的综合研究表明:1该混杂岩体以变质橄榄岩、橄榄辉长岩、细粒辉长岩为主;2变质橄榄岩具有低铬、钛、贫钙和高镁的特点,辉长岩类具有富铝、钛含量中等的特点;3微量元素富、稀土元素含相容元素Cr、Ni、Co,而贫大离子亲石元素LILE(不相容元素)K、Rb、Sr、Ba、Zr、Y、P、Ti等;4本区超基性岩的形成时代大约在早泥盆世早期。

The study on petrology,petrogeochemistry,trace elements,rare earth elements and U-Pb isotopic dating of ophiolite m＆#233;lange belt in Xibo area of Inner Mongolia shows that：1）the ophiolite belt primarily in-cludes metamorphic peridotite,olivine gabbro and fine-grained gabbro,2）the metamorphic peridotite is char-acterized by low chromium and titanium,poor calcium and high magnesium,and the gabbro is characterized by rich aluminum and medium titanium,3）the trace elements are rich,and rare earth elements contain com-patible elements such as Cr,Ni and Co,while Large Ion Lithophile Elements （LTLE）such as K,Rb,Sr, Ba,Zr,Y,P and Ti are poor,4）the Early Devonian System witnesses the formation of ultrabasic rocks in this area.