| 阿尔金北缘沟口泉古元古代蛇绿混杂岩(绿岩)地质特征及意义 |
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| 引用本文： | 曹福根,董富荣.阿尔金北缘沟口泉古元古代蛇绿混杂岩(绿岩)地质特征及意义[J].西北地质,2014(4):47-60. |
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| 作者姓名： | 曹福根 董富荣 |
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| 作者单位： | 新疆地矿局第一区域地质调查大队,新疆乌鲁木齐830013 |
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| 基金项目： | 中国地质调查局项目“新疆1：5万若羌县阿尔金山沟口泉等四幅区域地质调查”（1212010781050） |
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| 摘 要： | 近年经过区域地质调查,在阿尔金北缘沟口泉地区新识别出一套古元古代蛇绿混杂岩,其由洋壳岩块、上覆岩系及外来岩块等组成,洋壳岩块包括变质橄榄岩-堆晶超镁铁质岩、辉长质杂岩、斜长岩、斜长花岗岩、辉绿岩和镁铁质火山熔岩等,为一层序较完整的蛇绿岩套。根据对其各组成单元分布、岩石组合、岩石学、地球化学、同位素年代学等方面的研究以及在变质辉橄岩、斜长岩、辉长岩和玄武岩等岩石中获得锆石U-Pb SHRIMP定年加权平均值年龄(1 889±27)Ma、(1 869±27)Ma、(1 836±40)Ma、(1 818±25)Ma及数个2 200~2 600Ma单点年龄数据,证实了阿尔金北缘地区新太古宙末-古元古代存在一洋盆,并于古元古代末俯冲碰撞闭合形成了沟口泉蛇绿混杂岩,初步判定其为地幔柱型(P型)蛇绿岩。该发现为塔里木南缘阿北-敦煌地块与阿尔金造山带新太古宙末—古元古代构造演化提供了充分依据,对早前寒武纪地壳演化研究具有重要的地质意义。
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| 关 键 词： | 蛇绿混杂岩 古元古代 地幔柱型(P型) 沟口泉 |
Geology and Tectonic Significance of the Paleproterozoic Ophiolitic Melange in Goukouquan,Northern Margin of Altun |
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| CAO Fu-gen,DONG Fu-rong.Geology and Tectonic Significance of the Paleproterozoic Ophiolitic Melange in Goukouquan,Northern Margin of Altun[J].Northwestern Geology,2014(4):47-60. |
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| Authors: | CAO Fu-gen DONG Fu-rong |
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| Institution: | (No. 1 Regional Geological Survey Team, Bureau of Geology and Mineral Resources, Urumqi 830013, China) |
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| Abstract: | After regional geological surveys in recent years, a new ophiolitic melange of Paleprot- erozoic Era was identified in Goukouquan, northern margin of Altun, which consists of oceanic crust block, overlying rock series and exotic blocks. The oceanic crust rock is a complete sequence of ophiolite including metamorphic peridotite-ultramafic cumulates, gabbroic complex rock, anorthosite, plagiogranite, diabase, mafic volcanic lava and other components. Studies of the rock combination, petrology, geochemistry, isotopic geochronology and Zircon U-Pb SHRIMP dating on metamorphic iherzolite, anorthosite, gabbro, basalt specify their average ages as （1 889±27） Ma, （1 869±27） Ma, （1 836±40） Ma, （1 818±5） Maandseveral2 200 Ma- 2 600 Ma age data as isolated points, confirming that there is an ocean basin from late Neoarchean Era to Paleproterozoic Era in northern Altun area, which then dived, collided and closed to form the ophiolitic melange of Goukouquan, which can be speculated as mantle plume （P-Type） ori- gin. This discovery provided a sufficient basis for tectonic evolution from late Neoarchean Era to Paleproterozoic Era in Dunhuang block and Altun orogenic belt and will be of great significance for the research on Cambrian crustal evolution. |
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| Keywords: | ophiolilic melange Paleproterozoic Era mantle plume origin Goukouquan |
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