西昆仑阿卡阿孜山杂岩体的特征和成因  

Characteristics and Origin of the Akaraz Shan Complex in the Western Kunlun Mountains

作　　者：谌宏伟[1] 罗照华[2,3] 莫宣学[2,3] 詹华明[2] 

机构地区：[1]中国地质大学水资源与环境学院,北京100083 [2]中国地质大学地球科学与资源学院,北京100083 [3]中国地质大学"岩石圈构造,深部过程及探测技术"教育部重点实验室

出　　处：《现代地质》2005年第2期189-197,共9页Geoscience

基　　金：中国地质调查局"东;西昆仑地质构造对比研究"项目 (200113900069 4 3);中国地质调查局"东昆仑造山带岩浆混合花岗岩及其填图方法基础研究"项目 (200113900018 5)。

摘　　要：阿卡阿孜山杂岩体位于西昆仑昆南地体南侧, 被新藏公路横切出一条南北长约2km的剖面。在剖面范围内可见二长闪长岩、石英二长闪长岩、花岗闪长岩、二长花岗岩、正长花岗岩和碱长花岗岩等多种岩石类型出露。通过详细研究岩体的野外地质特征、地球化学和同位素地球化学特征发现: 岩体中出现不平衡矿物组合; 镁铁质微粒包体中可见石英和长石捕虏晶; 各岩石样品的痕量元素配分型式呈现相似性; 岩体的Sr、Nd、Pb同位素体系同时具有地幔和下地壳的贡献等, 认为岩体形成于壳幔岩浆混合作用, 幔源岩浆底侵作用可能是混合作用的直接原因。由此推测, 幔源岩浆底侵作用是西昆仑地区印支晚期岩浆活动的重要诱发机制。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

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 

分 类 号：P588.1[天文地球—岩石学]