| Silurian Sedimentation in the South Qilian Belt: Arc-Continent Collision-related Deposition in the NE Tibet Plateau? |
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| 作者姓名： | YAN Zhen FU Changlei Jonathan C. AITCHISON ZHOU Renjie Solomon BUCKMAN CHEN Lei |
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| 作者单位： | Institute of Geology;School of Earth and Environmental Sciences;School of Earth&Environmental Science |
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| 基金项目： | the National Natural Science Foundation of China(Grants 41672221,41872241);China Geological Survey(Grants DD20190006,DD2016020104);IGGCAS Open Research Foundation(SKLK201702)。 |
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| 摘 要： | The South Qilian belt mainly comprises an early Paleozoic arc-ophiolite complex, accretionary prism, microcontinental block, and foreland basin. These elements represent accretion-collision during Cambrian to Silurian time in response to closure of the Proto-Tethyan Ocean in the NE of the present-day Tibet Plateau. Closure of the Proto-Tethyan Ocean between the Central Qilian block and the Oulongbuluke block and the associated collision took place from NE to SW in a zipper-like style. Sediment would have been dispersed longitudinally SW-ward with a progressive facies migration from marginal alluvial sediments toward slope deep-water and deep-sea turbidites. This migration path indicates an ocean basin that shrank toward the SW. The Balonggongga'er Formation in the western South Qilian belt represents the fill of a latest Ordovician-Silurian remnant ocean basin that separated the Oulongbuluke block from the Central Qilian block, and records Silurian closure of the Proto-Tethyan Ocean and subduction beneath the Central Qilian block. However, alluvial deposits in the Lajishan area were accumulated in a retro-foreland basin, indicating that continent-continent collision in the eastern South Qilian belt occurred at c. 450–440 Ma. These results demonstrate that the Proto-Tethyan Ocean closed diachronously during early Paleozoic time.
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| 关 键 词： | remnant ocean basin Qilian Orogen arc-continental collision Proto-Tethyan Ocean |
| 收稿时间： | 2020/4/5 0:00:00 |
| 修稿时间： | 2020/6/15 0:00:00 |
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