How long did the Tethyan one-way train operate?
Abstract
Tethys is a giant and long-lived oceanic system between what once was Gondwana in the south and what has become Laurasia in the north. Its evolution can be broadly represented by the Proto-, Paleo-, and Neo-Tethys oceans, formed in the Early Paleozoic, Late Paleozoic, and Mesozoic, respectively. The final oceanic closure in the Cenozoic resulted in formation of the Alps, the Turkish-Iranian plateau, and the Himalayan-Tibetan plateau, representing the development of elevated topography within the tropical-to-subtropical climate belts. The Proto-Tethys formed by the first rifting of the northern Gondwana margin at c. 500 Ma, and the blocks drifted northward and collided with Tarim and North China, and formed the Proto-Tethyan orogeny at c. 440-420 Ma, with a wide Longmucuo-Shuanghu ocean located to the south. This scenario is comparable with the Appalachian-Caledonian orogeny between the Gondwana-derived Avalonian terrane and Laurentia and Baltic. Northward subduction of the Paleo-Tethys along the Longmucuo-Shuanghu trench made opening of the previously closed Kuangxiwa-Anemaqen ocean at ca. 380 Ma and spreading of the Jingshajiang-Ailaoshan ocean as a back-arc basin. During the Late Paleozoic, the western Paleo-Tethys (Rheic Ocean) was manifested by collision of Africa with Europe along the Variscan orogenic belt at 360-330 Ma; whereas in the east, the Paleo-Tethyan oceans among the North China, South China, and Indochina closed simultaneously at c. 250 Ma, with formation of the Cathaysian continent. Together with Laurasia to the north, Gondwana to the south, and the Variscan orogen to the west, a residual Paleo-Tethys ocean was trapped, and the final eustatic regression took place in the Late Triassic-Early Jurassic. Meanwhile, the northern Gondwanan margin resumed rifting with a series of blocks to form the Neo-Tethyan Ocean, which was subsequently closed in the Cenozoic. The above synthesis indicates that the Tethyan evolution is characterized by northward drift of the rifted continental blocks from Gondwana, and subsequently collision with Eurasia continuously throughout Phanerozoic time. Such northward drifting and subduction strongly suggests that the slab pull is a dominant geodynamic force of plate movement, and the role of mantle plume as a driving force needs further investigation.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMT025.0001W
- Keywords:
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- 1031 Subduction zone processes;
- GEOCHEMISTRY;
- 7218 Lithosphere;
- SEISMOLOGY;
- 8104 Continental margins: convergent;
- TECTONOPHYSICS;
- 8120 Dynamics of lithosphere and mantle: general;
- TECTONOPHYSICS