Polyphase exhumation in the western Qinling Mountains, China: Rapid Early Cretaceous cooling along a lithospheric-scale tear fault and pulsed Cenozoic uplift

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• 作者：Bianca Heberer^a ; ; Thomas Anzenbacher^a ; Franz Neubauer^a ; Johann Genser^a ; Yunpeng Dong^b ; Istvá ; n Dunkl^c
• 关键词：Qinling Mountain ; Age&ndash ; elevation-relationship ; Thermochronology ; Yanshanian orogeny ; Tibetan Plateau uplift
• 刊名：Tectonophysics
• 出版年：17 March, 2014
• 年：2014
• 卷：617
• 期：Complete
• 页码：31-43
• 全文大小：2377 K

文摘

The western sector of the Qinling-Dabie orogenic belt plays a key role in both Late Jurassic to Early Cretaceous 鈥淵anshanian鈥?intracontinental tectonics and Cenozoic lateral escape triggered by India-Asia collision. The Taibai granite in the northern Qinling Mountains is located at the westernmost tip of a Yanshanian granite belt. It consists of multiple intrusions, constrained by new Late Jurassic and Early Cretaceous U-Pb zircon ages (156 卤 3 Ma and 124 卤 1 Ma). Applying various geochronometers (⁴⁰Ar/³⁹Ar on hornblende, biotite and K-feldspar, apatite fission-track, apatite [U-Th-Sm]/He) along a vertical profile of the Taibai Mountain refines the cooling and exhumation history. The new age constraints record the prolonged pre-Cenozoic intracontinental deformation as well as the cooling history mostly related to India-Asia collision. We detected rapid cooling for the Taibai granite from ca. 800 to 100 掳C during Early Cretaceous (ca. 123 to 100 Ma) followed by a period of slow cooling from ca. 100 Ma to ca. 25 Ma, and pulsed exhumation of the low-relief Cretaceous peneplain during Cenozoic times. We interpret the Early Cretaceous rapid cooling and exhumation as a result from activity along the southern sinistral lithospheric scale tear fault of the recently postulated intracontinental subduction of the Archean/Palaeoproterozoic North China Block beneath the Alashan Block. A Late Oligocene to Early Miocene cooling phase might be triggered either by the lateral motion during India-Asia collision and/or the Pacific subduction zone. Late Miocene intensified cooling is ascribed to uplift of the Tibetan Plateau.