The isotopic age of composite granite mass U-Pb in Caoping,South Qinling is 2.046～2.066 million years,the age is late Triassic-Early Jurassic.Lithogeochemistry shows Caoping rock mass is high-K calc-alkaline quasi-I type peraluminous granite.In the trace amount,elements of Nb,Ti,Ba,Ta and P have negative anomaly,elements of Th,Pb,K and Rb have positive anomaly,the large ion lithophylic element Sr,Ba is relative loss,K,Rb is relatively enriched.The rare earth partition curve shows light rare earth element enrichment,and europium positive anomaly is the relative flat right-leaning curve mode.The specific value of Nb/La is 0.63-1.21,and Nb/Ta is 7.3-11.9,which shows the material sources are the mixed formation of the earth crust and mantle.The formation of Caoping rock mass was caused by delamination of lithosphere in Qinling orogenic belt,the properties of lithosphere of late Indosinian Qinling Orogenic Belt is converted from the squeeze system to the stretch system.
关键词
南秦岭/复式花岗岩/锆石U-Pb定年/地球化学
Key words
south Qinling/composite granite/zircon U-Pb dating/geochemical
维普
万方数据