徐多勋,魏立勇,张振,寇少磊,常亮,曹龙.西秦岭临潭地区隆务河组碎屑锆石U-Pb年龄、地球化学特征及沉积环境分析[J].西北地质,2020,53(2):102-125 U Duoxun,WEI Liyong,ZHANG Zhen,KOU Shaolei,CHANG Liang,CAO Long.U-Pb Age, Geochemical Characteristics and Sedimentary Environment Analysis of Detrital Zircons from the Longwuhe Formation in Lintan area, West Qinling[J].Northwestern Geology,2020,53(2):102-125
西秦岭临潭地区隆务河组碎屑锆石U-Pb年龄、地球化学特征及沉积环境分析
U-Pb Age, Geochemical Characteristics and Sedimentary Environment Analysis of Detrital Zircons from the Longwuhe Formation in Lintan area, West Qinling
投稿时间:2019-12-02  修订日期:2020-04-03
DOI:10.19751/j.cnki.61-1149/p.2020.02.006
中文关键词:  隆务河组;碎屑锆石物源分析;沉积环境;西秦岭
英文关键词:Longwuhe Formation;detrital zircon analysis of sediment source;sedimentary environment;West Qinling
基金项目:中国地质调查局地质调查项目“甘肃美武—临潭地区1∶5万区域地质矿产调查”(DD2016007901)
作者单位
徐多勋 中国地质调查局西安矿产资源调查中心(原中国人民武装警察黄金第五支队), 陕西 西安 710000 
魏立勇 中国地质调查局西安矿产资源调查中心(原中国人民武装警察黄金第五支队), 陕西 西安 710000 
张振 中国地质调查局西安矿产资源调查中心(原中国人民武装警察黄金第五支队), 陕西 西安 710000 
寇少磊 中国地质调查局西安矿产资源调查中心(原中国人民武装警察黄金第五支队), 陕西 西安 710000 
常亮 中国地质调查局西安矿产资源调查中心(原中国人民武装警察黄金第五支队), 陕西 西安 710000 
曹龙 中国地质调查局西安矿产资源调查中心(原中国人民武装警察黄金第五支队), 陕西 西安 710000 
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中文摘要:
      以西秦岭造山带临潭地区早三叠世隆务河组碎屑岩为研究对象,进行LA-ICP-MS锆石U-Pb年代学研究,探讨其形成时代和源区,推断其沉积环境。所获得碎屑锆石年龄可划分为259~418 Ma(16.8%)、448~474 Ma(2.9%)、848~1 115 Ma(2.9%)和1 701~2 672 Ma(77.4%)四组,最小年龄为259 Ma,说明隆务河组沉积时代不早于晚二叠世。综合区域资料限定隆务河组沉积时代为早三叠世,物源总体来自隆务河盆地北侧新太古代-古元古代火山岩基底,包括华北板块、西秦岭造山带北缘、祁连造山带东段。结合地球化学及沉积相特征推断隆务河组砂岩主体形成于活动大陆边缘,为扩张阶段的弧后裂陷盆地。
英文摘要:
      Taking the clastic rocks of the early Triassic Longwuhe Formation in Lintan area, West Qinling orogenic belt, as the research object, the LA-ICP-MS zircon U-Pb geochronology was carried out to explore its formation age and source, and to infer its sedimentary environment. The ages of the obtained detrital zircon can be divided into 4 groups:259-418 Ma(16.8%),448-474 Ma(2.9%),848-1 115 Ma(2.9%)and 1 701-2 672 Ma(77.4%). The minimum age is 259 Ma, indicating that the sedimentary age of the Longwuhe Formation is not earlier than the Late Permian. The comprehensive regional data define the sedimentary age of the Longwuhe Formation as early Triassic. Sediment source is generally from Neo-archean-Paleoproterozoic volcanic basement in the northern side of the Longwuhe basin, including the North China Plate, the northern margin of the Western Qinling orogenic belt, and the eastern section of the Qilian orogenic belt. Combined with geochemical and sedimentary facies characteristics, it is concluded that the main body of the Longwuhe Formation sandstone formed in the active continental margin. The prototype of the basin should be the post-arc rift basin in the expansion stage.
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