关键词: 西昆仑, 阿卡阿孜山杂岩体, 印支晚期, 岩浆混合作用, 岩浆底侵作用

Abstract:

Akaraz Shan complex is located in the south zone of the Western Kunlun Mountains, cropping out a 2 km long section along the Xinjiang-Tibet road, which including some rock types such as monzodiorite, quartzmonzodiorite, granodiorite, monzogranite, syenogranite and alkaline feldspar granite. By studying the geological, geochemical and isotopic geochemical characteristics of the complex, the disequilibrium mineral assemblages, appearance of the quartz and feldspar xenocrysts in the mafic microgranular enclaves, similarity of the trace element distribution patterns of the rock samples, and contribution of the mantle and lower crust to the complex's Sr, Nd and Pb isotopic systems were found. It was concluded that the complex originated from crust-and mantle-derived magma mixing, and the mantle-derived magma underplating was the efficient amse of the magma mixing.Therefore, the mantle-derived magma underplating was probably an important mechanism that resulted in the magmatic activities of the Late Indosinian in the Western Kunlun area.

Key words: the Western Kunlun Mountains, Akaraz Shan complex, Late Indosinian, magma mixing, magma underplating