西秦岭池地山岩体地球化学特征及构造演化意义

Geochemical features and tectonic evolution significance of Chidishan pluton in west Qinling

西秦岭池地山岩体侵位于三叠纪大河坝组,属“S”形花岗岩类型。大离子亲石元素的富集与高场强元素的强烈亏损揭示了上述岩体具有相似的源区特征。锆石U-Pb测年显示,在三叠纪末期,由于板块边缘伸展—收缩造山作用,下地壳岩石重熔上涌与陆壳熔融的岩浆混合形成该岩体,侵入时代为印支期。

The Chidishan rock massem placed in Triassic Daheba Formation,belonging to "S" type granite.The enrichment of large ion lithophile elements and the strong depletion of high field strength elements reveal that the above rocks have similar source characteristics.Zircon U-Pb dating shows that at the end of Triassic,due to plate margin extension-contraction orogenesis,remelting and upwelling lower crust rocks mixed with molten magma of continental crust,and the intrusion occurred in Indosinian period.