Formation of the Great Bend and Enhanced Quaternary Incision of the Upper Yangtze River: New Insights from Low-Temperature Thermochronology and Tributary Morphology
The occurrence of a sharp turn along the upper course of the Yangtze River is referred to as the “Great Bend” and represents a large-scale drainage reorganization in response to the surface rise of the Tibetan Plateau. However, the timing and mechanism of the formation of the Great Bend remain dispu...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
GeoScienceWorld
2024-03-01
|
| Series: | Lithosphere |
| Online Access: | https://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/2023/Special%2014/1/6330617/lithosphere_2023_244.pdf |
| _version_ | 1797205818347618304 |
|---|---|
| author | Yong Zheng Jiawei Pan Haibing Li Yang Wang Zheng Gong Mingkun Bai |
| author_facet | Yong Zheng Jiawei Pan Haibing Li Yang Wang Zheng Gong Mingkun Bai |
| author_sort | Yong Zheng |
| collection | DOAJ |
| description | The occurrence of a sharp turn along the upper course of the Yangtze River is referred to as the “Great Bend” and represents a large-scale drainage reorganization in response to the surface rise of the Tibetan Plateau. However, the timing and mechanism of the formation of the Great Bend remain disputed. In this paper, we report new (U–Th)/He and apatite fission track thermochronological data from the deep river valley in the Great Bend area of the southeastern margin of the Tibetan Plateau. Compared with the adjacent Jianchuan Basin, two phases of younger rapid cooling for the Great Bend area are identified based on thermal-history modeling, namely, Miocene (ca. 17 to 11–8 Ma) and Quaternary, with the former phase being contemporaneous with the formation of the anticline in the Tiger Leaping Gorge. Progressive increases in the normalized channel steepness (ksn) and the degree of river-valley incision with increasing distance downstream for tributaries of the Yangtze River in the Tiger Leaping Gorge indicate that river rerouting and formation of the Great Bend occurred during the Miocene. Samples located at the bottom of the Tiger Leaping Gorge also reveal a phase of rapid cooling since ca. 1.9 Ma, with an exhumation rate of 1.5 ± 0.2 mm/year. We hypothesize that enhanced Quaternary exhumation in the southeastern margin of the Tibetan Plateau occurred mainly within the narrow region between the Sichuan Basin and the Eastern Himalayan Syntaxis, corresponding to an episode of widespread extensional deformation superimposed above middle- to upper-crustal flexure in this region. |
| first_indexed | 2024-04-24T08:57:10Z |
| format | Article |
| id | doaj.art-0fc9104630674375bb39f49da21a7872 |
| institution | Directory Open Access Journal |
| issn | 1941-8264 1947-4253 |
| language | English |
| last_indexed | 2024-04-24T08:57:10Z |
| publishDate | 2024-03-01 |
| publisher | GeoScienceWorld |
| record_format | Article |
| series | Lithosphere |
| spelling | doaj.art-0fc9104630674375bb39f49da21a78722024-04-16T05:46:30ZengGeoScienceWorldLithosphere1941-82641947-42532024-03-012023Special 1411810.2113/2023/lithosphere_2023_244Formation of the Great Bend and Enhanced Quaternary Incision of the Upper Yangtze River: New Insights from Low-Temperature Thermochronology and Tributary MorphologyYong Zheng0https://orcid.org/0000-0002-8166-8912Jiawei Pan1https://orcid.org/0000-0003-3201-3706Haibing Li2https://orcid.org/0000-0001-8110-0545Yang Wang3Zheng Gong4Mingkun Bai5Key Laboratory of Continental Dynamics of Ministry of Natural Resources, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037, ChinaKey Laboratory of Continental Dynamics of Ministry of Natural Resources, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037, ChinaKey Laboratory of Continental Dynamics of Ministry of Natural Resources, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037, ChinaSouthern Marine Science and Engineering Guangdong Laboratory, Guangzhou, 511458, ChinaInstitute of Geophysics, China Earthquake Administration, Beijing, 100081, ChinaState Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing, 100029, ChinaThe occurrence of a sharp turn along the upper course of the Yangtze River is referred to as the “Great Bend” and represents a large-scale drainage reorganization in response to the surface rise of the Tibetan Plateau. However, the timing and mechanism of the formation of the Great Bend remain disputed. In this paper, we report new (U–Th)/He and apatite fission track thermochronological data from the deep river valley in the Great Bend area of the southeastern margin of the Tibetan Plateau. Compared with the adjacent Jianchuan Basin, two phases of younger rapid cooling for the Great Bend area are identified based on thermal-history modeling, namely, Miocene (ca. 17 to 11–8 Ma) and Quaternary, with the former phase being contemporaneous with the formation of the anticline in the Tiger Leaping Gorge. Progressive increases in the normalized channel steepness (ksn) and the degree of river-valley incision with increasing distance downstream for tributaries of the Yangtze River in the Tiger Leaping Gorge indicate that river rerouting and formation of the Great Bend occurred during the Miocene. Samples located at the bottom of the Tiger Leaping Gorge also reveal a phase of rapid cooling since ca. 1.9 Ma, with an exhumation rate of 1.5 ± 0.2 mm/year. We hypothesize that enhanced Quaternary exhumation in the southeastern margin of the Tibetan Plateau occurred mainly within the narrow region between the Sichuan Basin and the Eastern Himalayan Syntaxis, corresponding to an episode of widespread extensional deformation superimposed above middle- to upper-crustal flexure in this region.https://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/2023/Special%2014/1/6330617/lithosphere_2023_244.pdf |
| spellingShingle | Yong Zheng Jiawei Pan Haibing Li Yang Wang Zheng Gong Mingkun Bai Formation of the Great Bend and Enhanced Quaternary Incision of the Upper Yangtze River: New Insights from Low-Temperature Thermochronology and Tributary Morphology Lithosphere |
| title | Formation of the Great Bend and Enhanced Quaternary Incision of the Upper Yangtze River: New Insights from Low-Temperature Thermochronology and Tributary Morphology |
| title_full | Formation of the Great Bend and Enhanced Quaternary Incision of the Upper Yangtze River: New Insights from Low-Temperature Thermochronology and Tributary Morphology |
| title_fullStr | Formation of the Great Bend and Enhanced Quaternary Incision of the Upper Yangtze River: New Insights from Low-Temperature Thermochronology and Tributary Morphology |
| title_full_unstemmed | Formation of the Great Bend and Enhanced Quaternary Incision of the Upper Yangtze River: New Insights from Low-Temperature Thermochronology and Tributary Morphology |
| title_short | Formation of the Great Bend and Enhanced Quaternary Incision of the Upper Yangtze River: New Insights from Low-Temperature Thermochronology and Tributary Morphology |
| title_sort | formation of the great bend and enhanced quaternary incision of the upper yangtze river new insights from low temperature thermochronology and tributary morphology |
| url | https://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/2023/Special%2014/1/6330617/lithosphere_2023_244.pdf |
| work_keys_str_mv | AT yongzheng formationofthegreatbendandenhancedquaternaryincisionoftheupperyangtzerivernewinsightsfromlowtemperaturethermochronologyandtributarymorphology AT jiaweipan formationofthegreatbendandenhancedquaternaryincisionoftheupperyangtzerivernewinsightsfromlowtemperaturethermochronologyandtributarymorphology AT haibingli formationofthegreatbendandenhancedquaternaryincisionoftheupperyangtzerivernewinsightsfromlowtemperaturethermochronologyandtributarymorphology AT yangwang formationofthegreatbendandenhancedquaternaryincisionoftheupperyangtzerivernewinsightsfromlowtemperaturethermochronologyandtributarymorphology AT zhenggong formationofthegreatbendandenhancedquaternaryincisionoftheupperyangtzerivernewinsightsfromlowtemperaturethermochronologyandtributarymorphology AT mingkunbai formationofthegreatbendandenhancedquaternaryincisionoftheupperyangtzerivernewinsightsfromlowtemperaturethermochronologyandtributarymorphology |