鹰峰岩体时代对柴北缘滩间山地区万洞沟群时代的制约  

Constraints of the Age of Yingfeng Rock Mass on the Age of Wandonggou Group in Tanjianshan Area of the Northern Margin of Qaidam

作　　者：余吉远 李向民 计波 王毅智[2] 祁栋 YU Jiyuan;LI Xiangmin;JI Bo;WANG Yizhi;QI Dong(Xi an Center of China Geological Survey,Northwest China Center for Geoscience Innovation,Centre for Orogenic Belt Geology,Xi an 710054,Shaanxi,China;Qinghai Geological Survey Institute,Xining 810012,Qinghai,China;The First Exploration Institute of Geology and Mineral Resources in Qinghai Province,Haidong 810600,Qinghai,China)

机构地区：[1]中国地质调查局西安地质调查中心/西北地质科技创新中心/中国地质调查局造山带地质研究中心,陕西西安710054 [2]青海省地质调查院,青海西宁810012 [3]青海省第一地质矿产勘查院,青海海东810600

出　　处：《西北地质》2021年第3期1-9,共9页Northwestern Geology

基　　金：国家自然科学基金“中天山阿拉塔格环状杂岩体成因研究”(41202045);中国地质调查局地质矿产调查项目“祁连成矿带肃南—大柴旦地区地质矿产调查”(DD20160012)。

摘　　要：万洞沟群岩石组合主要为碳酸盐岩、片岩和千枚岩,具有良好的金矿找矿地质背景,但是其形成时代的不确定性及其与达肯达坂群的区分困难,对万洞沟群的展布规律没有形成统一认识,导致柴北缘滩间山地区的金矿找矿工作进展缓慢。通过对侵入其中的鹰峰环斑花岗岩的时代开展锆石U-Pb年代学研究,获得(1773.1±3.7)Ma的加权平均年龄,并收集到鹰峰环斑花岗岩与直接围岩的侵入接触关系证据、万洞沟群产出的中元古代化石等的形成时代,与达肯达坂群进行区域对比,将鹰峰环斑花岗岩岩体的直接围岩万洞沟群b段重新厘定为达肯达坂群,优化了万洞沟群的现实定义,这对柴北缘滩间山地区金矿找矿工作部署将起到积极的作用。Wandonggou Group is mainly composed of carbonate,schist and phyllite,preferable geologically for gold deposit prospecting.However,there has not been a unified understanding on the distribution law of the Wandonggou Group because of the uncertainty of its forming age and the difficulty in distinguishing it from Daken Daban Group,which results in slow proceeding in gold deposit prospecting in Tanjianshan area of the northern margin of Qaidam.This paper carried out zircon U-Pb chronology research on the age of the intruding Yingfeng rapakivi granite and obtained the weighted average age of(1773.1±3.7)Ma.The intrusive contact of Yingfeng rapakivi granit with the direct surrounding rock,the formation age of Mesoproterozoic fossils from Wandonggou Group and the regional comparison with Daken Daban Group redefined segment B of Wandonggou Group,the direct surrounding rock of Yingfeng rapakivi granite,as Daken Daban Group.The optimized definition of Wandonggou Group provides a basis for the deployment of the gold deposit prospecting in the northern margin of Qaidam and the Tanjianshan Area.

关 键 词：万洞沟群 鹰峰环斑花岗岩 锆石U-PB 柴北缘 

分 类 号：P534[天文地球—古生物学与地层学]