浙皖晚中生代仙霞岩体锆石UPb年代学、地球化学及成岩地质意义
DOI:
作者:
作者单位:

浙江省地质调查院,浙江省地质调查院,浙江省地质调查院,浙江省地质调查院,浙江省地质调查院,浙江省地质调查院,浙江省地质调查院,浙江省地质调查院

作者简介:

通讯作者:

中图分类号:

基金项目:

国土资源部中国地质调查局项目 (编号:1212011220527)资助


Zircon UPb Geochronology and Geochemistry of the Late Mesozoic Xianxia Rock in Zhejiang and Anhui Provinces and Diagenetic Geological Significance
Author:
Affiliation:

Zhejiang Institute of Geological Survey,Zhejiang institute of geological survey,Zhejiang institute of geological survey,Zhejiang institute of geological survey,Zhejiang institute of geological survey,Zhejiang institute of geological survey,Zhejiang institute of geological survey,Zhejiang institute of geological survey

Fund Project:

  • 摘要
  • |
  • 图/表
  • |
  • 访问统计
  • |
  • 参考文献
  • |
  • 相似文献
  • |
  • 引证文献
  • |
  • 资源附件
  • |
  • 文章评论
    摘要:

    仙霞岩体是浙北和皖南交界区域明显受北东向学川-孝丰断裂构造带控制的大岩体,其内部岩性复杂,主要由早期中粒二长花岗岩、巨斑状二长花岗岩和晚期中粗粒正长花岗岩、细粒正长花岗岩组成,后期有大量细晶岩、石英正长岩、闪长玢岩、安山岩、辉绿岩等脉岩侵入。锆石UPb年龄数据显示早期二长花岗岩大约侵位于1451~1442Ma,晚期正长花岗岩大约侵位于131.7~130.8Ma,后期辉绿岩脉侵位于128.3Ma。两期岩石均具高SiO2、高K2O+Na2O和低P2O5特征;早期二长花岗岩为准铝质、高钾钙碱系列岩石,稀土配分曲线强右倾,中等负Eu异常,富集Rb、Th、U、K,亏损Ba、Nb、Sr、P、Ti等特征;晚期正长花岗岩为准铝质-过铝质、钾玄岩系列岩石,稀土配分曲线弱右倾、强负Eu异常,同样富集Rb、Th、U、K,强亏损Sr、P、Ti等特征;均属高分异I型花岗岩类。两期岩石均具有相对高的(86Sr/87Sr)i值(0.70807~0.70988)和εNd(t)值(-8.87~-5.14),Nd二阶段模式年龄为1.36~1.65 Ga。成岩可能与古太平洋板块俯冲角度的改变,构造背景由中晚侏罗世(165±5~145±5Ma)的挤压环境向早白垩世早期(145±5~125Ma)的伸展拉张环境转变有关,致使古老江南造山带地壳物质熔融并可能混染扬子岩石圈地幔物质形成的两期岩浆经高程度结晶分离作用先后侵位,也表明浙西北乃至华南地区晚中生代构造转换时间为145Ma左右,且在早白垩世发生了多期次伸展拉张作用。

    Abstract:

    Xianxia rock is mass rocks that are obviously controlled by the NE tectonic in Zhejiang and Anhui, with complicated lithology content mainly composed of early medium grain monzogranite porphyritic monzogranite and late medium coarsegrain,fine grained syenogranite, and later intrusded by a large number of vein rocks, such as fine crystal rock, quartz syenite, diorite, andesite, diabase,etc.Zircon UPb age data indicate that early monzogranite emplaced about in 1451~1442Ma,late syenogranite emplaced about in 1317~1308Ma,the late diabase dikes emplaced in 1283Ma. Both periods rocks belong to highly fractionated Itype granitoids, with the characterictic of high SiO2and low P2O5; early monzogranite belongs to the metaluminous, highk calc alkaline series, with the characteristic of strong right tendency REE curve, moderate negative Eu anomalies, enrichment of Rb, Th, U, K,and depletion of Ba, Nb,Sr,P,Ti,etc; late syenogranite belongs to metaluminousaluminum, shoshonitic series, with the characteristic of weak right tendency REE curve, strong negative Eu anomalies, enrichment of Rb, Th, U, K,and strong depletion of Sr,P,Ti,etc. Both rocks show relatively high(86Sr/87Sr)ivalue (0.70807~0.70988) and epsilon Nd(t) values (-8.87~-5.14),two stage Nd model age is between 1.36~1.65 Ga.The Early Cretaceous Diagenesis in Zhejiang and Anhui may be related to the changing of the Pacific plate subduction angle, a tectonic background changing from MiddleLate Jurassic(165±5~145±5Ma)compressive environment into earlyearly Cretaceous (145±5~125Ma) extensive environment, resulting in a highdegree crystallization and differentiation the two stage magma which formed by the partial melting of the ancient Jiangnan orogenic belt crustal and may be contaminatedly the Yangtze lithospheric mantle materials.

    参考文献
    相似文献
    引证文献
引用本文

张建芳,龚瑞君,汪隆武,蔡晓亮,徐双辉,陈津华,陈小友,汪建国.2017.浙皖晚中生代仙霞岩体锆石UPb年代学、地球化学及成岩地质意义[J].地质学报,91(1):198-212.
ZHANG Jianfang, GONG Ruijun, WANG Longwu, CAI Xiaoliang, XU Shuanghui, CHEN Jinhua, CHEN Xiaoyou, WANG Jianguo.2017. Zircon UPb Geochronology and Geochemistry of the Late Mesozoic Xianxia Rock in Zhejiang and Anhui Provinces and Diagenetic Geological Significance[J]. Acta Geologica Sinica,91(1):198-212.

复制
分享
文章指标
  • 点击次数:
  • 下载次数:
  • HTML阅读次数:
  • 引用次数:
历史
  • 收稿日期:2015-09-17
  • 最后修改日期:2016-01-06
  • 录用日期:2017-01-12
  • 在线发布日期: 2017-01-16
  • 出版日期: