Early tectonic uplift of the northern Tibetan Plateau

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	Early tectonic uplift of the northern Tibetan Plateau
	Dai, SA ; Fang, XM ; Song, CH ; Gao, JP ; Gao, DL; Li, JJ
	2005-08-01
发表期刊	CHINESE SCIENCE BULLETIN
ISSN	1001-6538
卷号	50 期号:15 页码:1642-1652
关键词	Hexi Corridor Huoshaogou Formation Cenozoic Magnetostratigraphy Tibet Uptift
摘要	The Hexi Corridor is the northmost foreland basin of the Tibetan Plateau and its formation is controlled by the northern marginal fault of Tibet, Altyn Tagh Fault (ATF)-North Qilian Shan marginal Fault (NQF), and the southern Kuantan Shan-Longshou Shan Fault (KLF). So its study is important to understanding the mechanism of Tibet formation and its influence on global climate change. The oldest Cenozoic sediments in the Corridor is the Huoshaogou Formation which consists of terrigenous fine conglomerate, sandstone, sandy mudstone and mudstone, depositing in alluvial to lacustrine and fan delta sedimentary environments. Detailed paleomagnetic measurements of this sequence at Yumen clearly reveal eleven pairs of normal and reversed polarities. Fossil mammals found around the section support that most of the observed polarities can be well correlated with chrons between 13n and 18r of the standard geomagnetic polarity time scale, yielding ages of 40.2-33.35 Ma. The mean declinations of this sequence and its immediately above stratigraphy indicate an 18.3 degrees rapid clockwise rotation of the Hexi Corridor. Since this sequence has been strongly folded and is capped by an angular unconformity, we think that the presence of the thick alluvial fan conglomeration at the bottom of the foreland basin may indicate the initial deformation and uplift of the northern Qilian Shan. This process could occur at latest at 40.2 Ma, driven by the faults NQF and KLF that thrust onto the Hexi corridor respectively from its southern and northern margins. These faults are in an early response to the collision of India with Asia, while the unconformable termination and rotation of the Huoshaogou Formation at similar to 33.35 Ma indicate other early episode of rapid tectonic deformation and uplift of the northern Tibet. The Hexi Corridor is the northmost foreland basin of the Tibetan Plateau and its formation is controlled by the northern marginal fault of Tibet, Altyn Tagh Fault (ATF)-North Qilian Shan marginal Fault (NQF), and the southern Kuantan Shan-Longshou Shan Fault (KLF). So its study is important to understanding the mechanism of Tibet formation and its influence on global climate change. The oldest Cenozoic sediments in the Corridor is the Huoshaogou Formation which consists of terrigenous fine conglomerate, sandstone, sandy mudstone and mudstone, depositing in alluvial to lacustrine and fan delta sedimentary environments. Detailed paleomagnetic measurements of this sequence at Yumen clearly reveal eleven pairs of normal and reversed polarities. Fossil mammals found around the section support that most of the observed polarities can be well correlated with chrons between 13n and 18r of the standard geomagnetic polarity time scale, yielding ages of 40.2-33.35 Ma. The mean declinations of this sequence and its immediately above stratigraphy indicate an 18.3 degrees rapid clockwise rotation of the Hexi Corridor. Since this sequence has been strongly folded and is capped by an angular unconformity, we think that the presence of the thick alluvial fan conglomeration at the bottom of the foreland basin may indicate the initial deformation and uplift of the northern Qilian Shan. This process could occur at latest at 40.2 Ma, driven by the faults NQF and KLF that thrust onto the Hexi corridor respectively from its southern and northern margins. These faults are in an early response to the collision of India with Asia, while the unconformable termination and rotation of the Huoshaogou Formation at similar to 33.35 Ma indicate other early episode of rapid tectonic deformation and uplift of the northern Tibet.; The Hexi Corridor is the northmost foreland basin of the Tibetan Plateau and its formation is controlled by the northern marginal fault of Tibet, Altyn Tagh Fault (ATF)-North Qilian Shan marginal Fault (NQF), and the southern Kuantan Shan-Longshou Shan Fault (KLF). So its study is important to understanding the mechanism of Tibet formation and its influence on global climate change. The oldest Cenozoic sediments in the Corridor is the Huoshaogou Formation which consists of terrigenous fine conglomerate, sandstone, sandy mudstone and mudstone, depositing in alluvial to lacustrine and fan delta sedimentary environments. Detailed paleomagnetic measurements of this sequence at Yumen clearly reveal eleven pairs of normal and reversed polarities. Fossil mammals found around the section support that most of the observed polarities can be well correlated with chrons between 13n and 18r of the standard geomagnetic polarity time scale, yielding ages of 40.2-33.35 Ma. The mean declinations of this sequence and its immediately above stratigraphy indicate an 18.3 degrees rapid clockwise rotation of the Hexi Corridor. Since this sequence has been strongly folded and is capped by an angular unconformity, we think that the presence of the thick alluvial fan conglomeration at the bottom of the foreland basin may indicate the initial deformation and uplift of the northern Qilian Shan. This process could occur at latest at 40.2 Ma, driven by the faults NQF and KLF that thrust onto the Hexi corridor respectively from its southern and northern margins. These faults are in an early response to the collision of India with Asia, while the unconformable termination and rotation of the Huoshaogou Formation at similar to 33.35 Ma indicate other early episode of rapid tectonic deformation and uplift of the northern Tibet.
语种	英语
引用统计
文献类型	期刊论文
条目标识符	http://ir.isl.ac.cn/handle/363002/2323
专题	青海盐湖研究所知识仓储中国科学院青海盐湖研究所
作者单位	1.Minist Educ China, Key Lab Western Chinas Environm Syst, Lanzhou 730000, Peoples R China 2.Lanzhou Univ, Coll Resources & Environm, Lanzhou 730000, Peoples R China 3.Chinese Acad Sci, Inst Tibetan Plateau Res, Beijing 100085, Peoples R China 4.Chinese Acad Sci, Qinghai Inst Salt Lakes, Xining 810008, Peoples R China
推荐引用方式 GB/T 7714	Dai, SA,Fang, XM,Song, CH,et al. Early tectonic uplift of the northern Tibetan Plateau[J]. CHINESE SCIENCE BULLETIN,2005,50(15):1642-1652.
APA	Dai, SA,Fang, XM,Song, CH,Gao, JP,Gao, DL,&Li, JJ.(2005).Early tectonic uplift of the northern Tibetan Plateau.CHINESE SCIENCE BULLETIN,50(15),1642-1652.
MLA	Dai, SA,et al."Early tectonic uplift of the northern Tibetan Plateau".CHINESE SCIENCE BULLETIN 50.15(2005):1642-1652.