全文快速搜索:          
引用本文:王行军 王根厚 李广栋 吴连亨 李金和 高 雄 张双增 专少鹏 班长勇. 西藏西部札达县东北部帮果日—波库蛇绿岩带的发现及其地质意义[J]. 中国地质, 2013, 40(6): 1749-1761.
WANG Xing-jun, WANG Geng-hou, LI Guang-dong, WU Lian-he, LI Jin-he, GAO Xiong, ZHANG Shuang-zeng, ZHUAN Shao-peng, BAN Chang-yong. The discovery of Banguori-Boku ophiolite belt in northeastern Zanda County of west Tibet and its geological significance[J]. Geology in China, 2013, 40(6): 1749-1761(in Chinese with English abstract).
【打印本页】   【HTML】   【下载PDF全文】   查看/发表评论  下载PDF阅读器  关闭
←前一篇|后一篇→ 过刊浏览    高级检索
本文已被:浏览 1685次   下载 1902 本文二维码信息
码上扫一扫!
分享到: 微信 更多
西藏西部札达县东北部帮果日—波库蛇绿岩带的发现及其地质意义
王行军 王根厚 李广栋 吴连亨 李金和 高 雄 张双增 专少鹏 班长勇1,2,3
1.中国地质大学地球科学与资源学院,北京 100083;2.中国人民武装警察部队黄金地质研究所,河北 廊坊 065000;3.河北省区域地质矿产调查研究所,河北 廊坊 065000
摘要:
提要:帮果日—波库蛇绿岩带位于雅鲁藏布江缝合带的最西段,由帮果日蛇绿岩和波库混杂岩构成,呈北西展布,长128 km,宽5~10 km。帮果日蛇绿岩由方辉橄榄岩和二辉橄榄岩构成,岩石由橄榄石(Fo=85.2~88.0,平均86.6)、顽火辉石(Mg#=89.3~94.3,平均91.2)、透辉石(Mg#=92.0~94.9,平均93.1)构成,以高铝(Al2O3=0.96%~2.10%)、高钛(Ti=173~261μg/g)为特征,微量元素含量与MOR地幔岩的接近,亏损REE,ΣREE仅为球粒陨石的33%~71%,估算其为原始地幔经过6%~12%部分熔融的产物。波库混杂岩基质由板岩、粉砂质板岩构成,岩块有橄榄岩、辉长岩、硅质岩、砂岩、灰岩等。通过对帮果日蛇绿岩同位素测年结果、波库混杂岩之中硅质岩岩块放射虫化石的研究,确定帮果日—波库蛇绿岩带形成于晚白垩世,是新特提斯洋俯冲消减的产物;帮果日蛇绿岩代表了新特提斯洋洋壳的残留,属典型的MOR型蛇绿岩。
关键词:  蛇绿岩  MOR  混杂岩  新特提斯洋  帮果日  波库
DOI:
分类号:
基金项目:中国地质调查局地质调查项目(200213000010)资助。
The discovery of Banguori-Boku ophiolite belt in northeastern Zanda County of west Tibet and its geological significance
WANG Xing-jun, WANG Geng-hou, LI Guang-dong, WU Lian-he, LI Jin-he, GAO Xiong, ZHANG Shuang-zeng, ZHUAN Shao-peng, BAN Chang-yong1,2,3
1. School of Geosciences and Resource, China University of Geology, Beijing 10083, China;2. Gold Geological Institute of CAPF, Langfang 065000, Hebei, China;3. Hebei Institute of Regional Geological and Mineral Resource Survey, Langfang 065000, Hebei, China
Abstract:
Abstract: Located at the westernmost end of Yarlung Zangbo suture zone, the Bangguori-Boku ophiolite belt is composed of NW-striking Bangguori ophiolite and Boku melange 128 km in length and 5-10 km in width. Bangguori ophiolite consists of harzburgite and lherzolite comprising olivine (Fo=85.2~88.0, 86.6 on average), enstatite (Mg# =89.3~94.3, 91.2 on average), and diopside (Mg#=89.3~94.3, 93.1 on average), characterized by high Al2O3 (0.96%~2.10%) and Ti (173~261μg/g), close to the trace element content of MOR mantle rock, and depletion of REE with ΣREE being 0.33~0.71 times that of chondrite. Moreover, major and trace element characteristics indicate that Bangguori ophiolites are restites resulting from 6%~12% partial melting of the primitive mantle. Boku melange consists of groundmass of slate and silty slate, and rock mass of peridotite, gabbro, siliceous rock, sandstone and limestone. Studies show that Baoguori-Boku ophiolite belt was formed during Late Cretaceous, as evidenced by isotope dating of Bangguori ophiolite and radiolarians fossils from the silicolite rock mass of Boku melange. The results obtained by the authors demonstrate that Bangguori-Boku ophiolite belt resulted from Neotethys ocean subduction, and Bangguori ophiolite represents the residuum of Neotethys ocean lithosphere and belongs to the typical MOR-type ophiolite.
Key words:  ophiolite  MOR  melange  Neotethys ocean  Bangguori  Boku