Does pulsed Tibetan deformation correlate with Indian plate motion changes?

Li, S. and van Hinsbergen, D.J.J. and Najman, Y. and Liu-Zeng, J. and Deng, C. and Zhu, R. (2020) Does pulsed Tibetan deformation correlate with Indian plate motion changes? Earth and Planetary Science Letters, 536. ISSN 0012-821X

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Abstract

Models that aim to explain the causes of the significant Indian plate motion acceleration around 70 Ma, and the subsequent deceleration around 52 Ma predict different scenarios regarding crustal shortening of the Tibetan Plateau, which can be tested by precisely determining the timing of regional shortening events in Tibet. Here we attempt to determine this timing by presenting a high-resolution magnetostratigraphy of a ∼3.5 km thick sedimentary sequence in the syn-contractional Gonjo Basin, east-central Tibet. We successfully isolated the primary remanence as confirmed by positive fold and reversal tests. Correlation to the geomagnetic polarity time scale reveals a 69–41.5 Ma age for the Gonjo Basin sedimentary succession. Average sedimentation rates indicate two episodes of enhanced sediment accumulation rate at 69–64 Ma and 52–48 Ma, which coincide with periods of vertical axis rotation recorded in the basin fill. This coincidence suggests a tectonic cause, which given regional structures we interpret as shortening pulses. Our results are similar to those from basins elsewhere in southern, central and northern Tibet, suggesting plateau-wide, synchronous shortening pulses at ∼69–64 Ma and ∼52–48 Ma. These pulses are synchronous with major acceleration and deceleration of India-Asia convergence rate, suggesting that both the acceleration and deceleration of India-Asia convergence may be associated with enhanced crustal deformation in Tibet, which we use to evaluate previous dynamic models explaining the Indian plate motion changes and India-Asia collision processes.

Item Type:
Journal Article
Journal or Publication Title:
Earth and Planetary Science Letters
Additional Information:
This is the author’s version of a work that was accepted for publication in Earth and Planetary Science Letters. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Earth and Planetary Science Letters, 536, 2020 DOI: 10.1016/j.epsl.2020.116144
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1900/1912
Subjects:
ID Code:
141877
Deposited By:
Deposited On:
27 Feb 2020 16:10
Refereed?:
Yes
Published?:
Published
Last Modified:
20 Sep 2020 05:54