宝兴厂矿区喜山期复式岩体锆石地球化学特征及其地质意义  

Geochemical Features of Zircons from the Himalayan Complexes in Baoxingchang,Western Yunnan and Their Geological Significances

作　　者：刀艳[1] 李峰[1] 吴静[1] 王蓉[1] 吕俊男 

机构地区：[1]昆明理工大学国土资源工程学院,昆明650093

出　　处：《地质科技情报》2016年第3期28-38,共11页Geological Science and Technology Information

基　　金：国家自然科学基金项目(40872040);云南省科技厅自然科学基金项目(2011FZ035)

摘　　要：对滇西宝兴厂矿区复式岩体锆石进行了阴极发光（Cathodoluminescence）和激光探针等离子质谱（LA-ICP-MS）分析。结果显示锆石发育良好的振荡环带,且Th/U比值〉0.1;大部分锆石REE含量极高,且HREE富集、LREE亏损、强烈的正Ce异常和轻微的负Eu异常,是典型的花岗岩岩浆锆石。锆石Hf同位素结果显示,εHf（t）值变化于-0.4～2.7,二阶段模式年龄（TDM2）介于0.83～1.00Ga,继承锆石年龄为0.93～1.54Ga,指示显著的壳幔混合过程：印度大陆壳与欧亚大陆壳碰撞俯冲,深部地幔岩浆上涌,造成新生代-中生代基底物质部分熔融,形成以壳源为主的壳-幔混源岩浆。Restricted by the NW Jinshajiang-Red River fault and NS Chenghai fault,Baoxingchang complex,one of alkali-rich porphyries in western Yunnan,consists of porphyritic granite,syenite porphyry,granite porphyry and alkali-feldspar granite porphyry.This study has analysed zircons in Baoxingchang complexes by cathodoluminescence and LA-ICP-MS.Cathodoluminescence（CL）images and REE analysis results of these zircons suggest that typical magmatic zircons characterized by oscillatory zoning and the Th/U ratios0.1,have high REE,considerable LREE depletion,HREE enrichment,positive Ce and Eu anomalies in chondrite-normalized REE patterns,which belongs to typical granite magmatic zircon.In addition,the Hf isotopes of zircons spaning anεHf（t）range of-0.4-2.7,and the TDM2（Hf）at an range of0.83-1.00 Ga in magmatic zircons and 0.93-1.54 Ga in inherited zircons,suggest significant crust-mantle interaction process for magma.The partial melting of Cenozioc-Mesozioc crustal basement and mantle magma upwelling along deep fracture occur as a result of collision and indentation of India into Asia,forming crust-derived magma mixed with mantle-derived magma.

关 键 词：微量元素 HF同位素 复式岩体 宝兴厂 

分 类 号：P588.12[天文地球—岩石学] P59[天文地球—地质学]