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云南元谋县黄瓜园花岗岩锆石LA-ICP-MS U-Pb定年和岩石地球化学及其地质意义
  • ISSN号:0371-5736
  • 期刊名称:《地质论评》
  • 时间:0
  • 分类:P588.14[天文地球—岩石学;天文地球—地质学]
  • 作者机构:[1]中山大学海洋学院,广州510275, [2]成都地质矿产研究所,成都610081, [3]中山大学地球科学与地质工程学院,广州510275, [4]广东省海洋资源与近岸工程重点实验室,广州510006
  • 相关基金:本文为国土资源大调查项目(编号1212010911064、1212010813066)、国家自然科学基金资助项目(编号u1302233,40830425,40173025)和国家重点基础研究发展规划(973)项目(编号2009CB421006)的成果.
中文摘要:

康滇地区是我国南方元古宇地层集中出露的地区,元古宙岩浆活动频繁,是研究扬子陆块早期地质构造演化的窗口,也是最近研究的热点.近年本项目组在南北走向的元谋—绿汁江深大断裂北部、云南元谋县黄瓜园地区识别出了中元古代晚期的片麻状花岗岩.花岗岩锆石的LA-ICP-MS U-Pb年龄为1069.4±6.9Ma(MSWD=0.47,n=18).岩石化学表现为较高的SiO2(平均值高达72.79%)和中等Na2O+ K2O(平均为6.62%),低TiO2(平均0.26%)、低CaO(平均0.79%)、低MgO(平均0.52%,Mg#平均值22.13)和高Al2O3(平均12.84%,A/CNK平均值为1.33)含量,总体表现为亚碱性花岗岩的特征.微量元素分析显示稀土元素总量(∑REE)为132.96×10^-6~278.72×10^-6,平均237.00×10^-6,稀土配分曲线明显呈轻稀土富集、重稀土亏损的特点;δEu在0.38 ~0.49之间;微量元素配模式明显亏损Ba、Ta、Nb、Sr、P和Ti,相对富集Rb、Th、U、K等大离子亲石元素和La、Zr、Hf、Y等元素.岩石地球化学特征显示本区花岗岩属于A2亚类,可能源于下地壳基性岩部分熔融,为板块碰撞后伸展构造背景下的产物.花岗岩锆石U-Pb定年和地球化学特征表明在中元古代末期,康滇地区除了发生过南北向的块体汇聚外,可能还可能发生过较大规模东西向的汇聚过程,为全球性格林威尔造山运动的组成部分.此外,该区花岗岩的时代与邻近拉拉IOCG矿床中辉钼矿的Re-Os年龄高度一致,表明拉拉铜铁矿床成矿物质的最终定位富集与中元古代晚期康滇地区微陆块东西方向汇聚后的伸展运动密切相关.

英文摘要:

Abstract: Proterozoic Eonothem stratum of South China are centralized outcropping in Kangdian area. The frequent magmatic activity in Proterozoic is the window of geological tectonic evolution study on Yangtze craton, which is a burning field of research in recent years. Our group have identified the late Mesoproterozoic gneissic granite lately in area of Huangguayuan, Yuanmou, Yunnan Province, located on the north of S--N-trending Yuanmou--Luzhijiang fault. The U-Pb age of zircons in granite is 1069.4±6.9Ma(MSWD =0.47, n = 18). The Huangguayuan granites are characterized by high SiO2 (ave. 72.79% ) , medium alkali contents (ave. Na20 + K20content of 6.62% ) , low TiO2 ( ave. 0.26% ) , low CaO ( ave. O. 79% ) , low MgO ( ave. 0.52% , ave. Mg# 22. 13 ) , and high A1203 ( ave. 12.84% , ave. A/CNK 1.33 ), exhibiting the features of sub-alkaline granite in the mass. The content of EREE is 132.96×10^-6 - 278.72×10^-6 with an averageEREE of 237.00×10^-6. They possess the obvious characteristic of high LREE and low HREE, with a δEu value of 0.38 - 0.49. The chondrite- normalized REE pattern displays right dipping curves. The trace element patterns show that Ba, Ta, Nb, St, P and Ti are obviously depleted, whereas La, Zr, Hf, Y and the large ion lithophile elements such as Rb, Th, U and K are relatively enriched. Petrochemistry shows that, the Huangguayuan granits are A-type granite originating from the partial melting of lower crust basic rock. The formation temperature of Huangguayuan granite is about 750℃, and it is the product of extensional tectonics after plate collision. The U-Pb age and geochemistry of granites indicate that, besides S--N-trending plate convergence, Kangdian area also probably underwent the large-scale E--W-trending convergence process in late Mesoproterozoic, which is a constituent part of global Grenvillian orogenic movement. The age of granite in this area is highly coincident with the Re-Os age of molybdenite in Lala IOCG deposit nearby. It means that ex

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期刊信息
  • 《地质论评》
  • 北大核心期刊(2011版)
  • 主管单位:中国科学技术协会
  • 主办单位:中国地质学会
  • 主编:杨文采
  • 地址:北京阜成门外百万庄路26号中国地质学会期刊处
  • 邮编:100037
  • 邮箱:georeview@cags.ac.cn
  • 电话:010-68999804
  • 国际标准刊号:ISSN:0371-5736
  • 国内统一刊号:ISSN:11-1952/P
  • 邮发代号:2-382
  • 获奖情况:
  • 中国期刊方阵“双效”期刊
  • 国内外数据库收录:
  • 美国化学文摘(网络版),美国地质文献预评数据库,日本日本科学技术振兴机构数据库,中国中国科技核心期刊,中国北大核心期刊(2004版),中国北大核心期刊(2008版),中国北大核心期刊(2011版),中国北大核心期刊(2014版),中国北大核心期刊(2000版)
  • 被引量:23413