【摘要】 根据花岗岩同源岩浆演化序列,将唐古拉山北坡木乃复式花岗岩体划分为5个单元,归并为木乃超单元。岩石类型依次为紫苏辉石石英二长岩、石英二长岩、二长花岗岩和石英二长斑岩,精确的锆石U-Pb法测年及磷灰石裂变径迹定年表明,它们侵位于晚白垩世晚期,冷却于古新世末。岩石地球化学以贫硅、富钾、贫铝、轻稀土强烈富集、δEu负异常较明显为特征,初始锶同位素比值(87Sr/86Sr)为0.706039～0.711251,上述岩石及岩石地球化学和同位素组成揭示了一个壳幔混熔的物源区。研究表明,中生代末花岗岩浆起源于壳幔混熔,为印-亚早期碰撞的产物,属同碰撞-晚造山期壳幔型花岗岩。更多还原

【Abstract】 According to the theory of the consanguineous evolution order, the multiple granite in the northern slope of Tanggula Mts. can be divided into five units which are grouped into a Munai super-unit. The rock type includes hypersthene-adamellite,adamellite,monzonite granite and beschtanite.Zircon U-Pb and apatite fission tracks dating indicate that these granite intruded in the latest stage of Cretaceous and cooled in the latest stage of Paleocene.The lithogeochemistry is characterized by the richment of K and LREE, the dilution of Si and Al and the apparent neglect anomalies in δEu,with the isotopic ratios of initial strontium (（）⁸⁷Sr/（）⁸⁶Sr )ranging from 0.706 039 to 0.711 251.The rocks,lithogeochemistry and isotopics reveal the existence of a crust-mantle mixture melting provenance. The research results indicate that the granite magma from late Mesozoic originates from the crust-mantle mixture melting.The granite is resulted from the Indo-asia collision and belongs to syncollision-late orogenic crust-mantle type granite.更多还原