Yan, Z. and Tian, Y. and Vermeesch, P. and Sun, X. and Rittner, M. and Carter, Andrew and Shao, C. and Huang, H. and Ji, X. (2018) Late Triassic tectonic inversion in the upper Yangtze Block: insights from detrital zircon U–Pb geochronology from southwestern Sichuan Basin. Basin Research 31 (1), pp. 92-113. ISSN 0950-091X.
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Abstract
The Sichuan Basin and the Songpan-Ganze terrane, separated by the Longmen Shan fold-and-thrust belt (the eastern margin of the Tibetan Plateau), are two main Triassic depositional centers, south of the Qinling-Dabie orogen. During the Middle – Late Triassic closure of the Paleo-Tethys Ocean the Sichuan Basin region, located at the western margin of the Yangtze Block, transitioned from a passive continental margin into a foreland basin. In the meantime, the Songpan-Granze terrane evolved from a marine turbidite basin into a fold-and-thrust belt. To understand if and how the regional sediment routing system adjusted to these tectonic changes, we monitored sediment provenance primarily by using detrital zircon U-Pb analyses of representative stratigraphic samples from the southwestern edge of the Sichuan Basin. Integration of the results with paleocurrent and published detrital zircon data from other parts of the basin identified a marked change in provenance. Early-Middle Triassic samples were dominated by Neoproterozoic (~700-900Ma) zircons sourced mainly from the northern Kangdian basement, whereas Late Triassic sandstones recorded a more diverse range of zircon ages, sourced from the Qinling, Longmen Shan and Songpan-Ganze terrane. This change reflects a major drainage adjustment in response to the Late Triassic closure of the Paleo-Tethys Ocean and significant shortening in the Longmen Shan thrust belt and the eastern Songpan-Ganze terrane. Further, by Late Triassic time, the uplifted northern Kangdian basement had subsided. Considering the eastward paleocurrent and depocenter geometry of the Upper Triassic deposits, subsidence of the northern Kangdian basement probably resulted from eastward shortening and loading of the Songpan-Ganze terrane over the western margin of the Yangtze Block in response to the Late Triassic collision between Yangtze Block, Yidun arc and Qiangtang terrane along the Ganze-Litang and Jinshajiang sutures.
Metadata
| Item Type: | Article |
|---|---|
| Additional Information: | This is the peer reviewed version of the article, which has been published in final form at the link above. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. |
| School: | Birkbeck Faculties and Schools > Faculty of Science > School of Natural Sciences |
| Research Centres and Institutes: | Earth and Planetary Sciences, Institute of |
| Depositing User: | Andy Carter |
| Date Deposited: | 20 Aug 2018 13:09 |
| Last Modified: | 02 Aug 2023 17:43 |
| URI: | https://eprints.bbk.ac.uk/id/eprint/23611 |
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