Early Cenozoic faulting of the northern Tibetan Plateau margin from apatite (U-Th)/He ages
Early Cenozoic faulting of the northern Tibetan Plateau margin from apatite (U-Th)/He ages
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DOI：
10.1016/j.epsl.2010.04.051
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发表时间：
2010-07-15
影响因子：
5.3
通讯作者：
Duvall, Alison R.
中科院分区：
文献类型：
--
作者：
Clark, Marin K.;Farley, Kenneth A.;Duvall, Alison R.
解释大陆变形分布性质的模型预测了应变和高地形远离板块边界的传播。然而，西藏造山带中越来越多的证据表明，在造山带历史的早期，现代高原的远北方范围发生了变形，因此我们目前对造山高原发育的力学认识是不完整的。新的磷灰石（U-Th）/He年龄从四个海拔断面记录的快速折返期有关的主要逆冲构造的上盘岩石的侵蚀脉冲。加速侵蚀被用来作为断层时间的代理，并在邻近前陆盆地的结构数据和沉积物积累的更大背景下进行解释。综合已有的地质、热年代学和沉积学资料，得到了西藏北方始新世中晚期区域挤压变形的发展图象。尽管板块边界位于南部>3000公里处，但我们将新生代早期的变形与印度和欧亚大陆之间碰撞的开始联系起来。无论这种变形是否同时形成了高地形，新生代早期的应变表明，自大陆碰撞开始以来，造山带的现代界限一直相对稳定，变形没有明显地传播到远离板块边界的地方。(C)2010 Elsevier B. V.保留所有权利。
Models to explain the distributed nature of continental deformation predict the propagation of strain and high topography away from the plate boundary. Yet a growing body of evidence in the Tibetan orogen suggests that deformation occurred at the far northern extent of the modern plateau early in the orogen's history and thus our current mechanical understanding of orogenic plateau development is incomplete. New apatite (U-Th)/He ages from four elevation transects document periods of rapid exhumation related to erosion pulses in hanging wall rocks of major thrust structures. Accelerated erosion is used as a proxy of fault timing, and is interpreted in a larger context of structural data and sediment accumulation in adjacent foreland basins. Helium results are synthesized with published geologic, thermochronometric, and sedimentologic data from which a growing picture of regional compressional deformation in Middle to Late Eocene time in northern Tibet emerges. We relate the early Cenozoic period of deformation to the initiation of collision between India and Eurasia, despite the fact that the plate boundary was located >3000 km to the south. Regardless of whether or not high topography was built simultaneously as a result of this deformation, early Cenozoic strain signifies that the modern limit of the orogen has been relatively stationary since continental collision began and that deformation has not significantly propagated farther away from the plate boundary in time. (C) 2010 Elsevier B.V. All rights reserved.