全文快速搜索:          
引用本文:吴昊,翟庆国,胡培远,唐跃,朱志才,王伟,谢超明,强巴扎西. 西藏班戈北部早白垩世火山岩:班公湖—怒江洋闭合的岩浆记录[J]. 中国地质, 2021, 48(5): 1623-1638.
WU Hao,ZHAI Qingguo,HU Peiyuan,TANG Yue,ZHU Zhicai,WANG Wei,XIE Chaoming,QIANGBA Zhaxi. Early Cretaceous volcanic rocks in northern Baingoin, Tibet: Magmatic record of the closure of the Bangong-Nujiang Ocean[J]. Geology in China, 2021, 48(5): 1623-1638(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 121次   下载 367 本文二维码信息
码上扫一扫!
分享到: 微信 更多
西藏班戈北部早白垩世火山岩:班公湖—怒江洋闭合的岩浆记录
吴昊1, 翟庆国1, 胡培远1, 唐跃1, 朱志才1, 王伟1, 谢超明2, 强巴扎西3
1.自然资源部深地动力学重点实验室, 中国地质科学院地质研究所, 北京 100037;2.吉林大学地球科学学院, 吉林 长春 130061;3.西藏地勘局区域地质调查大队, 西藏 拉萨 851400
摘要:
对班戈县北部马前乡地区的早白垩世安山岩和英安岩进行了详细的地质填图及岩石学、年代学、地球化学和Hf同位素研究。锆石U-Pb定年获得安山岩年龄分别为(108.0±1.5)Ma和(113.6±0.9)Ma;英安岩年龄为(106.7±1.9)Ma和(113.6±0.8)Ma。安山岩富集Th和U,亏损Nb、Ta和Ti,具有变化范围较大的Mg#值(25~63),锆石εHft)值(-8.6~+1.5)以负值为主,应当为幔源镁铁质熔体与壳源熔体的混合产物。英安岩具有与安山岩类似的微量元素成分特征及负的锆石εHft)值(-12.3~-8.1),应当是地壳部分熔融的产物。结合前人研究成果认为,这些早白垩世岩浆岩是约110 Ma沿班公湖-怒江缝合带岩浆大爆发的产物,可能与班公湖-怒江洋闭合之后的拉萨与羌塘地块陆-陆碰撞有关。
关键词:  早白垩世火山岩  地球化学  岩石成因  岩浆混合  地质调查工程  班公湖—怒江缝合带
DOI:10.12029/gc20210522
分类号:P588.142;P588.144
基金项目:国家自然科学基金项目(42072268、42002069、41872240)、第二次青藏高原综合科学考察(2019QZKK0703)和中国地质调查局项目(DD20190370、DD20190060)联合资助。
Early Cretaceous volcanic rocks in northern Baingoin, Tibet: Magmatic record of the closure of the Bangong-Nujiang Ocean
WU Hao1, ZHAI Qingguo1, HU Peiyuan1, TANG Yue1, ZHU Zhicai1, WANG Wei1, XIE Chaoming2, QIANGBA Zhaxi3
1.Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China;2.College of Earth Science, Jilin University, Changchun 130061, Jilin, China;3.Regional Geological Survey Party, Tibet Bureau of Geology and Mineral Exploration and Development, Lhasa 851400, Tibet, China
Abstract:
The petrological, zircon U-Pb dating, whole-rock geochemical, and zircon Hf isotopic data of the Early Cretaceous andesites and dacites in the Maqianxiang area of Baingoin County, Tibet, are reported. The zircon U-Pb ages of andesite are (108.0±1.5)Ma and (113.6±0.9) Ma, and those of dacite are (106.7±1.9) Ma and (113.6±0.8) Ma. The andesites are enriched in Th and U and depleted in Nb, Ta, and Ti, have variable Mg# values (25-63), and show mainly negative zircon εHf(t) values (-8.6 to +1.5). They are probably generated by mixing of mantle- and crust-derived melts. Dacite shares similar trace element features with the coeval andesite, and has negative zircon εHf(t) values (-12.3 to -8.1). It is interpreted as a product of partially melting crust. The andesite and dacite are interpreted as a product of the ca.110 Ma magmatism along the Bangong-Nujiang suture zone, and may be related to the continent-continent collision process after the closure of the Bangong-Nujiang Ocean.
Key words:  Early Cretaceous volcanics  geochemistry  petrogenesis  magma mixing  geological survey engineering  Bangong-Nujiang suture zone  Tibet