藏北班戈江错地区侵入岩体形成时代与岩石地球化学特征

详细信息    查看全文 | 推荐本文 |

英文篇名：Formation Age and Petrogeochemical Characteristics of Intrusive Rocks in Baingoin Area,Northern Tibet 作者：孔维华 ; 卢海波 ; 刘双江 ; 方明 ; 方洁 ; 肖霞 英文作者：Kong Weihua;LU Haibo;Liu ShuanJiang;Fang Ming;Fang Jie;Xiao Xia;Sixth Geological Brigade of Hubei Geological Bureau; 关键词：班—怒结合带 ; 地球化学 ; 岛弧 ; 同碰撞 英文关键词：Baingoin-Nujiang junction zone;;geochemistry;;island arc;;syn-collision 中文刊名：资源环境与工程 英文刊名：Resources Environment & Engineering 机构：湖北省地质局第六地质大队; 出版日期：2019-06-15 出版单位：资源环境与工程 年：2019 期：02 基金：西藏1∶5万班戈江错地区H46E002003等6幅区域地质矿产调查项目(项目编号:1212011221082) 语种：中文; 页：12-18+29 页数：8 CN：42-1736/P ISSN：1671-1211 分类号：P588.12;P59

摘要

班—怒结合带中部班戈江错地区存在大面积侵入岩,该岩体主要岩性为花岗闪长岩及二长花岗岩、斑状二长花岗岩。样品LA-ICP-MS锆石U-Pb年龄为114. 94±0. 93 Ma和115. 5±1. 1 Ma,形成时代为早白垩世。花岗闪长岩大离子亲石元素Rb、Th、K富集,呈现正异常,明显亏损高场强元素Nb、Ti、Ta,形成环境为俯冲环境下的岛弧—陆缘弧环境;斑状二长花岗岩大离子亲石元素Rb、Th、K富集,呈现正异常,Sr、Ti强烈亏损,形成环境为同碰撞构造环境,表明该地区洋—陆转换作用过程于早白垩世完成,中特提斯洋闭合,进入陆—陆碰撞阶段。
        There are large-scale intrusive rocks in Baingoin area in the middle of Baingoin-Nujiang junction zone. The main lithologies of the intrusive rocks are granodiorite,monzonitic granite and porphyry monzonitic granite. The LA-ICPMS zircon U-Pb ages of the samples are 114. 94 ± 0. 93 and 115. 5 ± 1. 1 Ma,forming in the Early Cretaceous. Large ion lithophile elements Rb,Th and K in granodiorite are enriched showing positive anomalies,and high field strength elements Nb,Ti and Ta are obviously depleted,forming an island arc-continental margin arc environment in subduction environment. Large ion lithophile elements Rb,Th and K in porphyritic monzonitic granite are enriched,showing positive anomalies,while Sr and Ti are strongly depleted. The formation environment is a syn-collisional tectonic environment,indicating that the process of ocean-land conversion was completed in the Early Cretaceous,and the Middle Tethyan Ocean closed and entered the stage of land-land collision.

引文

[1]潘桂棠,李兴振,王立全,等.青藏高原及邻区大地构造单元初步划分[J].地质通报,2002,21(11):701-707.
    [2] Tapponnier P,Zhiqin X,Roger F,et al. Oblique Stepwise Rise and Growth of the Tibet Plateau[J]. Science,2001,294(5547):1671-1677.
    [3] Yin A,Harrison T M. Geologic evolution of the Himalayan-Tibetan Orogen[J]. Annual Review of Earth and Planetary Sciences,2000,28(1):211-280.
    [4]潘桂棠,莫宣学,侯增谦,等.冈底斯造山带的时空结构及演化[J].岩石学报,2006,22(3):521-533.
    [5]潘桂棠,丁俊,王立全.青藏高原及邻区地质图说明书[M].成都:成都地图出版社,2004:1-133.
    [6]陈玉禄,陈国荣,张宽忠,等. 1∶25万班戈幅区域地质调查报告[R].北京:中国地质调查局,2002.
    [7] Wilson M. Igneous Petrogenesis[M]. London:Unwin Hyman,1989.
    [8]黄瀚霄,李光明,董随亮,等.西藏班戈地区青龙花岗闪长岩SHRIMP锆石U-Pb年龄及其地球化学特征[J].地质通报,2012,31(6):852-859.
    [9]李彬,向树元,冯德新,等.藏东察雅县察拉地区中生代花岗岩LAICP-MS锆石U-Pb年龄和构造环境[J].地质通报,2012,31(5):696-706.
    [10]潘桂棠,王立全,朱弟成.青藏高原区域地质调查中几个重大科学问题的思考[J].地质通报,2004,23(1):12-19.
    [11]肖序常,李廷栋.青藏高原的构造演化与隆升机制[M].广州:广东科技出版社,2000:239-268.
    [12]邱瑞照,周肃,邓晋福,等.西藏班公湖—怒江西段舍马拉沟蛇绿岩中辉长岩年龄测定:兼论班公湖—怒江蛇绿岩带形成时代[J].中国地质,2004,31(3):262-268.
    [13]康志强,许继峰,王保弟,等.拉萨地块北部白垩纪多尼组火山岩的地球化学形成的构造环境[J].地球科学——中国地质大学学报,2009,34(1):89-104.
    [14]李华亮.班公湖—怒江缝合带西段洋陆转换的标志及时间[D].武汉:中国地质大学(武汉),2014.