摘要
柴达木盆地北缘绿梁山地区的辉长岩侵入到古生代滩间山群及超基性岩中 ,地球化学、微量元素、稀土元素显示出源幔特征。选自其中的锆石明显具岩浆型锆石特点 ,4个单颗粒锆石U -Pb同位素年龄均为谐和年龄 ,2 0 6 Pb 2 38U表面年龄统计权重平均值为 (496 .3± 6 .2 )Ma ,代表了该岩体的结晶年龄 ,从而间接地否定了本区滩间山群的时代为晚奥陶世 -志留纪的认识。辉长岩与滩间山群是柴北缘活动大陆边缘火山岛弧的组成部分。此类岩体同位素地质年龄的确定对柴北缘榴辉岩。
The gabbros intrude into the Tanjianshan group of the Paleozoic and the ultrabasic rocks in Luliangshan area on the northern margin of the Qaidam basin. The geochemical data show that the gabbros came from the upper mantle. A fresh gabbro sample was selected for the U Pb isotopic dating of zircon resently. Four U Pb isotopic concordant data of single grain zircon yield only on age (496.3±6.2)Ma, which represents the crystallizing age of the gabbros. The large subduction related collision in Cambrian Ordovician was related to the consumption of the volcanic arc inluding the gabbros and other rocks.
出处
《前寒武纪研究进展》
2002年第1期36-40,共5页
Progress in Precambrian Research
基金
中国地质调查局区域地质调查项目 (2 0 0 0 130 0 0 10 0 81)资助
