Apatite fission track evidence for Neogene uplift in the eastern Kunlun Mountains, northern Qinghai–Tibet Plateau, China

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• 作者：Wanming Yuan ; Jinquan Dong ; Wang Shicheng and Andrew Carter
• 关键词：Apatite fission track ; Neogene ; exhumation ; Kunlun Mountains ; Qaidam Basin
• 刊名：Journal of Asian Earth Sciences
• 出版年：2006
• 出版时间：1 October 2006
• 年：2006
• 卷：27
• 期：6
• 页码：847-856
• 全文大小：646 K

文摘

Forty-one apatite fission track ages (AFT) were determined on samples collected along a N–S section of the eastern Kunlun Mountains across the Middle and South Kunlun Faults between Buqingshan and Dulan. Measured AFT ages lie between 25±2 and 130±10 Ma, and all are significantly younger than their host rock formation or sediment deposition ages. Modelling the AFT data identifies a two stage regional cooling history that spans the last 100 Myrs. The earliest cooling phase occurred between the late Jurassic and early Tertiary and involved a moderate level of cooling between 20 and 40 °C, equivalent to average exhumation rates of =15 m/Myr. The second phase of cooling took place from 20 Ma with cooling rates increasing tenfold. Average exhumation rates for this period are estimated to be in the range of 100–150 m/Myr. The first stage of protracted cooling is consistent with regional evidence from the Qiantang and Lhasa terrans where previous studies have noted low rates of denudation in relation to a back-arc extensional setting. The more recent acceleration in cooling seen in the Kunlun data coincides with an increase in sedimentation rates in the adjacent Qaidam Basin. This points to a phase of Neogene uplift and increased erosion of the Kunlun Range, although contemporaneous monsoon strengthening may also have had a role.