Sequence Stratigraphic and Geochemical Records of Paleo-Sea Level Changes in Upper Carboniferous Mixed Clastic–Carbonate Successions in the Eastern Qaidam Basin

The Upper Carboniferous strata in the eastern Qaidam Basin, comprising several hundred meters of thick, mixed clastic–carbonate successions that have been little reported or explained, provide an excellent geological record of paleoenvironmental and paleo-sea level changes during the Late Carbonifer...

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Main Authors: Yifan Li, Xiaojie Wei, Kui Liu, Kening Qi
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Journal of Marine Science and Engineering
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Online Access:https://www.mdpi.com/2077-1312/13/7/1299
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author Yifan Li
Xiaojie Wei
Kui Liu
Kening Qi
author_facet Yifan Li
Xiaojie Wei
Kui Liu
Kening Qi
author_sort Yifan Li
collection DOAJ
description The Upper Carboniferous strata in the eastern Qaidam Basin, comprising several hundred meters of thick, mixed clastic–carbonate successions that have been little reported or explained, provide an excellent geological record of paleoenvironmental and paleo-sea level changes during the Late Carboniferous icehouse period. This tropical carbonate–clastic system offers critical constraints for correlating equatorial sea level responses with high-latitude glacial cycles during the Late Paleozoic Ice Age. Based on detailed outcrop observations and interpretations, five facies assemblages, including fluvial channel, tide-dominated estuary, wave-dominated shoreface, tide-influenced delta, and carbonate-dominated marine, have been identified and organized into cyclical stacking patterns. Correspondingly, four third-order sequences were recognized, each composed of lowstand, transgressive, and highstand system tracts (LST, TST, and HST). LST is generally dominated by fluvial channels as a result of river juvenation when the sea level falls. The TST is characterized by tide-dominated estuaries, followed by retrogradational, carbonated-dominated marine deposits formed during a period of sea level rise. The HST is dominated by aggradational marine deposits, wave-dominated shoreface environments, or tide-influenced deltas, caused by subsequent sea level falls and increased debris supply. The sequence stratigraphic evolution and geochemical records, based on carbon and oxygen isotopes and trace elements, suggest that during the Late Carboniferous period, the eastern Qaidam Basin experienced at least four significant sea level fluctuation events, and an overall long-term sea level rise. These were primarily driven by the Gondwana glacio-eustasy and regionally ascribed to the Paleo-Tethys Ocean expansion induced by the late Hercynian movement. Assessing the history of glacio-eustasy-driven sea level changes in the eastern Qaidam Basin is useful for predicting the distribution and evolution of mixed cyclic succession in and around the Tibetan Plateau.
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spelling doaj-art-ca540a90eedd4d13bc2571a2d5c6be542025-08-20T03:58:26ZengMDPI AGJournal of Marine Science and Engineering2077-13122025-07-01137129910.3390/jmse13071299Sequence Stratigraphic and Geochemical Records of Paleo-Sea Level Changes in Upper Carboniferous Mixed Clastic–Carbonate Successions in the Eastern Qaidam BasinYifan Li0Xiaojie Wei1Kui Liu2Kening Qi3School of Energy Resources, China University of Geosciences (Beijing), 29th Xueyuan Rd., Haidian, Beijing 100083, ChinaInstitute of Geomechanics, Chinese Academy of Geological Sciences, 11th Renmin University South Rd., Haidian, Beijing 100081, ChinaChinese Academy of Geological Sciences, 26th Baiwanzhuang St., Haidian, Beijing 100044, ChinaExploration and Development Research Institute, Zhongyuan Oilfield Company, SINOPEC, Puyang 457001, ChinaThe Upper Carboniferous strata in the eastern Qaidam Basin, comprising several hundred meters of thick, mixed clastic–carbonate successions that have been little reported or explained, provide an excellent geological record of paleoenvironmental and paleo-sea level changes during the Late Carboniferous icehouse period. This tropical carbonate–clastic system offers critical constraints for correlating equatorial sea level responses with high-latitude glacial cycles during the Late Paleozoic Ice Age. Based on detailed outcrop observations and interpretations, five facies assemblages, including fluvial channel, tide-dominated estuary, wave-dominated shoreface, tide-influenced delta, and carbonate-dominated marine, have been identified and organized into cyclical stacking patterns. Correspondingly, four third-order sequences were recognized, each composed of lowstand, transgressive, and highstand system tracts (LST, TST, and HST). LST is generally dominated by fluvial channels as a result of river juvenation when the sea level falls. The TST is characterized by tide-dominated estuaries, followed by retrogradational, carbonated-dominated marine deposits formed during a period of sea level rise. The HST is dominated by aggradational marine deposits, wave-dominated shoreface environments, or tide-influenced deltas, caused by subsequent sea level falls and increased debris supply. The sequence stratigraphic evolution and geochemical records, based on carbon and oxygen isotopes and trace elements, suggest that during the Late Carboniferous period, the eastern Qaidam Basin experienced at least four significant sea level fluctuation events, and an overall long-term sea level rise. These were primarily driven by the Gondwana glacio-eustasy and regionally ascribed to the Paleo-Tethys Ocean expansion induced by the late Hercynian movement. Assessing the history of glacio-eustasy-driven sea level changes in the eastern Qaidam Basin is useful for predicting the distribution and evolution of mixed cyclic succession in and around the Tibetan Plateau.https://www.mdpi.com/2077-1312/13/7/1299eastern Qaidam BasinUpper Carboniferous stratamixed clastic–carbonate successioncarbon isotopesglacio-eustasy
spellingShingle Yifan Li
Xiaojie Wei
Kui Liu
Kening Qi
Sequence Stratigraphic and Geochemical Records of Paleo-Sea Level Changes in Upper Carboniferous Mixed Clastic–Carbonate Successions in the Eastern Qaidam Basin
Journal of Marine Science and Engineering
eastern Qaidam Basin
Upper Carboniferous strata
mixed clastic–carbonate succession
carbon isotopes
glacio-eustasy
title Sequence Stratigraphic and Geochemical Records of Paleo-Sea Level Changes in Upper Carboniferous Mixed Clastic–Carbonate Successions in the Eastern Qaidam Basin
title_full Sequence Stratigraphic and Geochemical Records of Paleo-Sea Level Changes in Upper Carboniferous Mixed Clastic–Carbonate Successions in the Eastern Qaidam Basin
title_fullStr Sequence Stratigraphic and Geochemical Records of Paleo-Sea Level Changes in Upper Carboniferous Mixed Clastic–Carbonate Successions in the Eastern Qaidam Basin
title_full_unstemmed Sequence Stratigraphic and Geochemical Records of Paleo-Sea Level Changes in Upper Carboniferous Mixed Clastic–Carbonate Successions in the Eastern Qaidam Basin
title_short Sequence Stratigraphic and Geochemical Records of Paleo-Sea Level Changes in Upper Carboniferous Mixed Clastic–Carbonate Successions in the Eastern Qaidam Basin
title_sort sequence stratigraphic and geochemical records of paleo sea level changes in upper carboniferous mixed clastic carbonate successions in the eastern qaidam basin
topic eastern Qaidam Basin
Upper Carboniferous strata
mixed clastic–carbonate succession
carbon isotopes
glacio-eustasy
url https://www.mdpi.com/2077-1312/13/7/1299
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