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Journal: |
Journal of Geophysical Research 2019 No.1
clicks:150 |
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Title:
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Author:
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Weiwei Bian1,2, Tianshui Yang1,2 , Yiming Ma1,2,3 , Jingjie Jin1,2, Feng Gao1,2, Suo Wang1,2, Wenxiao Peng1,2, Shihong Zhang1,2 , Huaichun Wu1 , Haiyan Li1 , Liwan Cao1 , and Yuruo Shi4 |
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Abstract:
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The breakup of eastern Gondwana is among the hottest topics in the Earth sciences because of
its effect on global climate during the Jurassic-Cretaceous, its influence on the evolution of life, and its
importance to paleogeographic reconstruction. To better constrain the Jurassic and Cretaceous
paleogeographic position of the Tethyan Himalaya and the breakup of eastern Gondwana, a combined
paleomagnetic and geochronological study was performed on the Zhela and Weimei Formations lava flows,
dated at ~138–135 Ma, in the Luozha area of the eastern Tethyan Himalaya. Both positive fold and reversal
tests together with a maximum grouping at 100% unfolding indicate that the characteristic remanent
magnetization directions are primary magnetizations acquired before folding. The tilt-corrected directions
yielded a paleopole at 0.9°N, 293.4°E with A95 = 7.0° and a corresponding paleolatitude of 53.5°S ± 7.0°S for
the Luozha sampling area (28.9°N, 91.3°E), validating that the original erupted position of the Zhela and
Weimei Formations lava flows was located in the center of the Kerguelen mantle plume. Our new results,
together with the published paleomagnetic, geochronological, and geochemical results, demonstrate that
the Comei-Bunbury large igneous province originated from the Kerguelen mantle plume. The temporal and
spatial relationships between the Comei-Bunbury large igneous province and the Kerguelen mantle plume
indicate that eastern Gondwana initially rifted at ~147 Ma and that the Indian Plate fully separated from the
Australian-Antarctic Plate before ~124 Ma. |
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