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Communication Dans Un Congrès Année : 2017

Paleomagnetism of Cretaceous limestones from western Tarim basin suggests negligible latitudinal offset yet significant clockwise rotation

Résumé

Large northward translation of central Asian crustal blocks has been reported from paleomagnetism of Cretaceous and Tertiary terrestrial sediments. This motion was initially taken as evidence of deformation occurred in the Asian interior as a result of indentation of the Indian Plate. However, because the amount of motion is far greater than geological observations, accuracy of the paleomagnetic record has become a controversial issue. To solve the problem, it has been shown that the latitudinal offset can be entirely attributed to inclination shallowing during deposition and compaction processes (Tan et al., 2003; Tauxe and Kent, 2004). On the other hand, coeval volcanic rocks from central Asia did record steeper paleomagnetic inclinations than terrestrial rocks (Gilder et al., 2003). To extend the effort of solving the controversy, we report paleomagnetic results of Cretaceous limestones from western Tarim basin. Our results show that the majority of our collections have been overprinted. Fortunately, a special type of limestones preserved stable characteristic remanence. Fold tests suggest a primary origin of the magnetization. Comparison of the paleomagnetic direction with the coeval expected direction from reference poles indicates a negligible amount of northward movement consistent with previous result of inclination correction based on magnetic fabrics, and a pattern of clockwise rotation symmetric with the style observed in the western flank of the Pamir ranges. Rock magnetic data will also be presented to support the accurate paleomagnetic record.
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Dates et versions

hal-03552721 , version 1 (02-02-2022)

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X. Tan, S. Gilder, Yan Chen, J. P. Cogné, V. E. Courtillot, et al.. Paleomagnetism of Cretaceous limestones from western Tarim basin suggests negligible latitudinal offset yet significant clockwise rotation. American Geophysical Union, 2017, San Francisco, United States. ⟨hal-03552721⟩
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