摘要
通过对四川冕宁沙坝及康定—泸定地区的斜长角闪岩 -TTG片麻岩的系统Sm -Nd同位素的测定 ,在该区首次获得 70 6Ma的Sm -Nd等时线年龄 .据此等时线年龄及其他样品的Nd亏损地幔模式年龄证明长期以来这套被当作太古宙 -古元古代的变质岩系是新元古代大陆裂解与其后紧接着的地幔柱引起的热变质作用的产物 .与已有数据相结合 ,初步认为扬子克拉通目前所出露的基底没有统一演化历史 。
The Kangding Group, outcropping around the northern segment of the western Yangtze craton, has been regarded as a typical Archean high-grade terrain for a long time. The Kangding-Luding and Mianning complexes are representatives of the group. An Sm-Nd isochron of 706 Ma was first obtained through the systematic determination of Sm-Nd isotopic composition in the amphibolites-TTG gneisses from the Shaba, Mianning county, Sichuan Province. The isochron and Nd depleted mantle model ages of other samples show that the complexes were metamorphic and anatectic products of Neoproterozoic mafic-ultra-mafic rocks after breakup of Rodinia by a mantle plume. All these evidences suggest that the present outcropping basements of the Yangtze craton are free of a united evolutionary history. Therefore, further study should be made of the basements of the Yangtze craton.
出处
《地球科学（中国地质大学学报）》
EI
CAS
CSCD
北大核心
2001年第3期279-285,共7页
Earth Science-Journal of China University of Geosciences
基金
国家自然科学基金项目!(No .49773183)
国土资源部"九五"重大基础项目!(No .95 0 110 5 )
