投稿时间：2018-09-24
修订日期：2019-02-09
网络发布日期：2019-07-03
中文摘要:姚安干沟金矿是三江铜金多金属成矿带上的一个重要矿床，处于金沙江-哀牢山-红河富碱斑岩带中段，大地构造隶属于扬子板块西缘内部。通过对干沟金矿深部煌斑岩开展锆石LA-ICP-MS U-Pb定年及Hf同位素分析，结果表明煌斑岩成岩时代为（31.12±0.88） Ma，样品锆石176Hf/177Hf值为0.282 217~0.282 476，对应的εHf（t）值范围变化在-7.70到-18.94之间。通过与区域同期岩体同位素综合对比分析，认为姚安干沟金矿床深部煌斑岩起源于交代富集岩石圈地幔的部分熔融与加厚下地壳部分熔融的混合岩浆，干沟煌斑岩以及区域上北衙、马厂箐等晚期煌斑岩均是对印度-欧亚大陆后碰撞时期岩石圈地幔发生拆沉的响应，产在应力场环境由压扭挤压向张扭伸展逐渐过渡的动力学背景下，为杂岩体晚期岩浆活动的产物。
Abstract:Located in the middle domain of the Jinshajiang-Ailaoshan-Red River alkaline porphyry belt as well as on the western margin of the Yangtze Block, the Gan'gou gold deposit is an important deposit in the Sanjiang CuAu polymetallic ore belt. In this paper, zircon LA-ICP-MS U-Pb isotopic dating and Hf isotopic analysis of lamprophyre samples collected from the deeper tunnel in the Gan'gou gold deposit were carried out. The results show that the formation age of the lamprophyre is (31.12±0.88) Ma, and the 176Hf/177Hf ratios range from 0.282 217 to 0.282 476, with εHf(t) values varying from -7.70 to -18.94. Based on these isotopic results and analyses of the lamprophyre from other areas of this region, the authors believe that the lamprophyre of the Gan'gou gold deposit was derived from the mixed magma by partial melting of metasomatic enrichment of lithospheric mantle and thickened lower crust. The regional tectonic geodynamics suggest that the lamprophyre in the Yao'an, Beiya, and Machangqin areas of this region all resulted from both of the delamination of the over-thickened CLM and transition from compressional to extensional setting after the post-collision between the India and Eurasia continents. It was also formed by the later magmatism of the alkaline volcanic-plutonic complex.
keywords:geochemistry lamprophyre gold deposit Hf isotope Yao'an
文章编号：
中图分类号：P618.51
文献标志码：
基金项目:本文得到国家自然科学基金项目（编号：41673060）和国家重点基础研究发展计划（973）项目（编号：2015CB452605）的联合资助
引用文本：
严清高,郭忠林,李超,江小均,王忠强,李亚东.2019.滇中姚安干沟金矿床煌斑岩锆石LA-ICP-MS U-Pb年代学及Hf同位素特征[J].矿床地质,38(3):526~540YAN QingGao,GUO ZhongLin,LI Chao,JIANG XiaoJun,WANG ZhongQiang,LI YaDong.2019.Zircon LA-ICP-MS U-Pb geochronology and Hf isotopes of lamprophyre in Gan'gou gold deposit, Yao'an County, Central Yunnan Province[J].Mineral Deposits38(3):526~540
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