论文部分内容阅读
对原划为新太古代古元古代康定杂岩的雅江桥片麻状奥长花岗岩、花滩奥长花岗岩和磨盘山花岗岩的地球化学分析表明,其具有低Mg#、Na2O>K2O,轻重稀土元素强烈分异,无或略具微弱的负Eu异常,低YbN、Cr、Ni、V、Nb、Ta、Ti,高Ba,Sr变化较大,与TTG类似。雅江桥奥长花岗岩的SHRI MP锆石U-Pb年龄测定结果为778±11Ma。初步认为本次工作所选的康定杂岩为形成于新元古代的TTG花岗岩。结合TTG的形成环境和前人研究成果,认为扬子地台西缘新元古代花岗岩是板块俯冲环境体制下玄武质洋壳部分熔融的产物。
The geochemical analyzes of the Yajiangqiao gneissic granite, Huatanian granite and Mopanshan granite, which were originally designated as Proterozoic kandong complex, show that they have low Mg #, Na2O> K2O, light and heavy rare earth The elements are highly differentiated and have no or slightly weak negative Eu anomaly. The variations of low YbN, Cr, Ni, V, Nb, Ta, Ti and high Ba, Sr are quite similar and similar to that of TTG. The SHRI MP zircon U-Pb dating of Yajiangqiao opal granite was 778 ± 11Ma. It is initially believed that the Kangding complex selected for this work is TTG granite formed in the Neoproterozoic. Combined with the forming environment of TTG and the previous research results, it is concluded that the Neoproterozoic granites on the western margin of Yangtze platform are the products of partial melting of basaltic oceanic crust under the plate-subduction environment.