Geochronology and the initiation of Altyn Fault, western China
Geochronology and the initiation of Altyn Fault, western China
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DOI：
10.3126/hjs.v2i4.875
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发表时间：
2008-02
期刊：
影响因子：
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通讯作者：
Yong‐jiang Liu;F. Neubauer;J. Genser;Xiaohong Ge;A. Takasu;Sihua Yuan
中科院分区：
文献类型：
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作者：
Yong‐jiang Liu;F. Neubauer;J. Genser;Xiaohong Ge;A. Takasu;Sihua Yuan
奥地利萨尔茨堡大学地质与古生物研究所的同位素测年实验室- argonaut的Ar/ 39ar方法与激光聚变40ar / 39ar测年系统。得到了几个年龄组。葛市断谷早中侏罗世黑云母等时年龄为92±2.7 Ma。在阿克塞—唐金关剖面中，远离阿尔金断裂带中部剪切带的样品显示出461 ~ 445.2 Ma和414.9 ~ 342.8 Ma两个高原年龄组。北断裂带的变形花岗质片麻岩样品具有178.4 ~ 137.5 Ma和89.2±1.6 Ma两个高原年龄，阿尔金断裂带中剪切带样品具有36.4 Ma和26.3 Ma两个高原年龄。461 ~ 445.2 Ma和414.9 ~ 342.8 Ma分别代表了晚奥陶世—早志留世和泥盆世阿尔金走滑断层移位的岩石中记录的构造-热事件。这两个年龄群应该与南北祁连洋的闭合有关，而与阿尔金断裂的活动无关。178.4 ~ 137.5 Ma被解释为中晚侏罗世—早白垩世阿尔金断裂的活动年龄，并与拉萨地块向北的增生有关。（92±2.7 ~ 89.2±1.6）Ma和（26.3 ~ 36.4）Ma的年龄组表明，晚侏罗世-晚始新世阿尔金断裂带发生了绿片岩相变质作用强烈的走滑运动。研究表明，在印度大陆与欧亚大陆交汇的构造背景下，阿尔金断裂具有多次脉冲式活动的特征。最近有一些关于……的建议或想法
Ar/ 39 Ar method in the Isotopic Dating Laboratory-ARGONAUT with a laser fusion 40 Ar/ 39 Ar dating system in the Institute of Geology and Paleontology, Salzburg University, Austria. Several age groups were obtained. Biotites of the Early-Middle Jurassic samples from Geshi fault-valley yield an isochron age of 92±2.7 Ma. In Aksay- Dangjin Pass profile, samples away from the middle shear zone of the Altyn fault belt yield two plateau age groups in the range of 461-445.2 Ma and 414.9-342.8 Ma. But the samples of deformed granitic gneiss from northern belt give two plateau age groups of 178.4-137.5 Ma and 89.2±1.6 Ma, while the sample from middle shear zone of Altyn fault belt yields two plateau ages of 36.4 Ma and 26.3 Ma. The age groups of 461-445.2 Ma and 414.9-342.8 Ma represent the tectono-thermal events that had been recorded in the rocks that were displaced by Altyn strike-slip fault in late Ordovician-Early Silurian and Devonian respectively. These two age groups should be related to the closures of Northern and Southern Qilian Oceans, not to the activities of Altyn fault. The ages of 178.4-137.5 Ma are interpreted as the active ages of Altyn fault in the Middle-Late Jurassic-Early Cretaceous, and should be related to the accretion of Lhasa Block to the north. The age groups of 92±2.7-89.2±1.6 Ma and 26.3-36.4 Ma suggest the strike- slip movements with strong metamorphism of greenschist facies along the Altyn fault in the Late Jurassic and Late Eocene. These tectonic thermal events occurred in most areas of northern Tibet Plateau and should be the response of the collision between Indian and Eurasian continents along the north margin. The study shows that the Altyn fault is characterized by multiple pulse-style activities under the tectonic setting of convergence between Indian and Eurasian continents. Recently there are several suggestions or ideas about the