南秦岭勉略蛇绿构造混杂带辉长辉绿岩类微量稀土元素地球化学

应用元素地球化学方法,研究了勉略带中辉长辉绿岩的相关特征,结果表明,勉略蛇绿构造混杂带内的辉长岩属高铝强碱质辉长岩类,是地幔橄榄岩部分熔融的产物。辉绿岩墙群属强碱铝质基性岩类,过渡族元素蛛网图与辉长岩类几乎完全相同,其不相容元素与辉长岩类总体趋势相一致,反映了一种递进岩浆演化趋势。因此,本区辉长岩与辉绿岩墙群具同源岩浆分异演化的地球化学特征,其均为勉略蛇绿岩的重要组成端元。

Geochemical features of trace and rare earth elements of gabbro-diabase in Mianlue ophiolitic melange zone,South Qinling

This paper studied the geochemical features of the gabbro-diabase in the Mianlue suture by element geochemistry method.The gabbro in the Mianlue ophiolitic melange zone exhibits high Al2O3and Na2O+ K2O contents,indicating an origin from the par-tial melting of the mantle peridotite. The diabase in the melange zone also exhibits high alkaline, showing almost the same distribu-tion pattern of transition metal elements and incompatible elements as the gabbro. It implies that the gabbro and the diabase in thestudied area belong to a comagmatic system. They are the important components of the Mianlue ophiolitic association.