Controls on the geometry and evolution of thin-skinned fold-thrust belts, and applications to the Makran accretionary prism and Indo-Burman Ranges

Ball, T. V. and Penney, C. E. and Neufeld, J. A. and Copley, A. C. (2019) Controls on the geometry and evolution of thin-skinned fold-thrust belts, and applications to the Makran accretionary prism and Indo-Burman Ranges. Geophysical Journal International, 218 (1). pp. 247-267. ISSN ISSN: 0956-540X, ESSN: 1365-246X DOI https://doi.org/10.1093/gji/ggz139

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Abstract

The formation of fold-thrust belts at convergent margins is a dynamic process. Accretion of weak sediments to the front of the overriding plate results in crustal thickening and continued flexural subsidence of the underthrusting plate. Fold-thrust belts are often treated as a Coulomb wedge having self-similar geometries with a critical taper, and either a rigid or isostatically compensated base. In this paper we build upon this work by developing a new dynamic model to investigate both the role of the thickness and material properties of the incoming sediment, and the flexure in the underthrusting plate in controlling the behaviour and evolution of fold-thrust belts. Our analysis shows that the evolution of fold-thrust belts can be dominated by either gravitational spreading or vertical thickening, depending on the relative importance of sediment flux, material properties and flexure. We apply our model to the Makran accretionary prism and the Indo-Burman Ranges, and show that for the Makran flexure must be considered in order to explain the dip of the sediment-basement interface from seismic reflection profiles. In the Indo-Burman Ranges, we show that incoming sediment thickness has a first-order control on the variations in the characteristics of the topography from north to south of the Shillong Plateau.

Item Type:	Article
Uncontrolled Keywords:	2019AREP; IA74
Subjects:	02 - Geodynamics, Geophysics and Tectonics
Divisions:	02 - Geodynamics, Geophysics and Tectonics 12 - PhD
Journal or Publication Title:	Geophysical Journal International
Volume:	218
Page Range:	pp. 247-267
Identification Number:	https://doi.org/10.1093/gji/ggz139
Depositing User:	Sarah Humbert
Date Deposited:	08 Apr 2019 11:38
Last Modified:	11 Mar 2021 18:48
URI:	http://eprints.esc.cam.ac.uk/id/eprint/4449

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