摘要
大通沟南山北闪长岩岩体位于柴达木地块西北缘,岩石类型为石英闪长岩、闪长岩、花岗闪长岩,具有高硅、富碱、富铝、贫钛特征。A/CNK值为1.52~1.57,均大于1.10,为强过铝质花岗岩;轻稀土富集,重稀土亏损,具负Eu异常,标准化曲线呈明显的右倾型;富集Rb、Th、K等大离子亲石元素和轻稀土元素,相对亏损Nb、Ti、Y、Yb等高场强元素,Sr、P、Ti元素呈“V”型谷,具有明显亏损。通过对地球化学研究,表明岩浆来源于以砂屑岩为主的壳幔混合源,岩体成因类型属Ⅰ-型花岗岩;LA-ICP-MS锆石U-Pb定年结果为(270±3)Ma(MSWD=0.076),系早—中二叠世岩浆活动的产物,形成于俯冲环境下的岛弧花岗岩。
The Datonggou Nanshanbei diorite body is located in the northwest Qaidam basin, with the main rock types quartz diorite, diorite and granodiorite, and it is characterized by high silicon, rich alkali, rich aluminum and poor titanium. A/CNK ranges from 1.52 to 1.57, more than 1.10, and belongs to strong peraluminous granite type. Light rare earth elements(LREE) is enriched while heavy rare earth elements is depleted, and there is negative Eu anomaly. The normalized curve is obviously right inclined, with the feature of enrichment of large ion lithophile elements Rb, Th, K and LREE and the relative depletion of high field strength elements Nb, Ti, Y, Yb. The elements such as Sr, P and Ti show a “V” shaped valley with obvious depletion. The geochemical study shows that the magma is derived from the crust-mantle mixed source mainly composed of arenaceous rocks, and the genetic type belongs to I-type granite. LA-ICP-MS zircon U-Pb dating shows that the zircon formation age is(270±3) Ma(MSWD=0.076), which is the product of magmatic activity in the Middle to Early Permian, and was formed in the island arc granite under subduction environment.
作者
刘军
息朝庄
黄波
杨涛
夏浩东
邓会娟
LIU Jun;XI Chaozhuang;HUANG Bo;YANG Tao;XIA Haodong;DENG Huijuan(Xi'an Northwest Noferrous Geophysical-Geochemical Corps Ltd.,Xi'an 710068,Shaanxi,China;School of Civil Engineering,Hunan City University,Yiyang 413000,Hunan,China;Geophysical Nonferrous Metals and Geochemical Survey,Non-ferrous Metals and Nuclear Industry Geological Exploration Bureau of Guizhou,Duyun 558000,Guizhou,China;College of Architecture and Urban Planning,Guizhou Institute of Technology,Guiyang 550000,Guizhou,China;Cores and Samples Center of Natural Resources,CGS,Yanjiao 065201,Hebei,China)
出处
《西北地质》
CAS
CSCD
北大核心
2022年第2期93-105,共13页
Northwestern Geology
基金
国家自然科学基金和贵州喀斯特科学研究中心联合项目(U1812402)
贵州理工学院高层次人才科研启动项目“贵州实物地质资料汇聚与服务体系建设研究”(XJGC20161101)
湖南省教育厅科学研究一般项目“湘东北万大型金矿床毒砂Re-Os年代学研究”(20C0381)
益阳市社科联项目(2021YS133)。
