Provenance Analysis of the Upper Triassic Langjiexue Group in the Southern Tibet, China
Provenance Analysis of the Upper Triassic Langjiexue Group in the Southern Tibet, China
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发表时间：
2004
影响因子：
2.1
通讯作者：
Li Xiang
中科院分区：
文献类型：
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作者：
Li Xiang
本文对藏南琼界、贡嘎地区上三叠统复理石朗杰雪群的物源进行了分析。从碎屑组分上看，砂体多为再生型和混合型造山物源。与Bhatia（1995）的观点相比，稀土元素和微量元素数据显示了造山带再循环构造中的混合母质。阴极发光下石英发出的棕色、淡紫色和蓝色或绿色光，证明了变质、火山和深成源区的可能性。因此，认为朗杰雪群的陆源沉积物来自于曾受再造造山带控制的母源，在此期间，结晶基底可能暴露于空气中，并与混杂岩复合体一起附着于大陆之上。朗杰雪群物源为混合物源。在上述物源讨论的基础上，我们提出了一个有争议的假设：（1）朗杰雪群可能是裂谷或残留海下的海底扇，甚至是前陆盆地前渊中的产物;（2）晚三叠世在印度次大陆与拉萨地块之间可能存在一个地块或微板块，并伴随着一条同时代的造山带。
Provenance of the flysch Langjiexue Group of Upper Triassic in Qiongjie and Gongga area of southern Tibet, China, is analyzed in the paper. By clastic component, most of sands fall in recycled and mixed orogenic provenances. REE and trace element data show a mixture of parent source in recycled orogen tectonics by comparison with those proposed by Bhatia (1995). Either brown, or pale violet and blue, or green light of Quartz under cathode luminescence proves possibilities of metamorphic, volcanic and plutonic sources. Therefore, it is proposed that terrigenous sediments in the Langjiexue Group are derived from a parent source where had ever been in control of recycled orogen, during which crystalline basement could be exposed under air and attached on to a continent with some complexes of melange. The provenance of the Langjiexue Group is of mixture. On the basis of discussion of provenance above, we disputably suppose that: (1) the Langjiexue Group could be a product generated in submarine fan under a rift or remnant sea, even in a foredeep of foreland basin; (2) there might be a block or microplate placed between Indian Subcontinent and Lhasa Block during Late Triassic, where a coeval orogenic belt should be accessory.