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A Late Eocene-Oligocene Through-Flowing River Between the Upper Yangtze and South China Sea
Geochemistry, Geophysics, Geosystems Số 7, năm 2020 (Tập 21, trang -)
ISSN: 15252027
ISSN: 15252027
DOI: 10.1029/2020GC009046
Tài liệu thuộc danh mục: ISI, Scopus
Article
English
Từ khóa: Binary alloys; Catchments; Erosion; Lead alloys; Offshore oil well production; Rivers; Sedimentology; Silicate minerals; Uranium alloys; Zircon; Detrital zircon; Detrital zircon grains; Erosion and sedimentation; Late Oligocene; Plateau uplift; Potential sources; South China sea; Tibetan Plateau; Sedimentary rocks; bedrock; detrital deposit; Eocene-Oligocene boundary; erosion; Paleogene; river flow; sedimentary rock; uranium-lead dating; zircon; China; Pacific Ocean; Qinghai-Xizang Plateau; South China Sea; Yangtze Basin
Tóm tắt tiếng anh
We test the hypothesis of a major Paleogene river draining the SE Tibetan Plateau and the central modern Yangtze Basin that then flowed south to the South China Sea. We test this model using U-Pb dated detrital zircon grains preserved in Paleogene sedimentary rocks in northern Vietnam and SW China. We applied a series of statistical tests to compare the U-Pb age spectra of the rocks in order to highlight differences and similarities between them and with potential source bedrocks. Monte Carlo mixing models imply that erosion was dominantly derived from the Indochina and Songpan-Garz Blocks and to a lesser extent the Yangtze Craton. Some of the zircon populations indicate local erosion and sedimentation, but others show close similarity both within northern Vietnam, as well as more widely in the Eocene Jianchuan, Paleocene-Oligocene Simao, and Oligocene-Miocene Yuanjiang basins of China. The presence of younger (<200Ma) zircons from the Qamdo Block of Tibet is less easily explicable in terms of recycling by erosion of older sedimentary rocks and implies a regional drainage linking SE Tibet and the South China Sea in the Late Eocene-Oligocene. Detrital zircons from offshore in the South China Sea showed initial local erosion, but with a connection to a river stretching to SE Tibet in the Late Oligocene. A change from regional to local sources in the Early Miocene in the Yuanjiang Basin indicates the timing of disruption of the old drainage driven by regional plateau uplift. 2020. American Geophysical Union. All Rights Reserved.