Principles of Shortening in Salt Basins Containing Isolated Minibasins

This is a Preprint and has not been peer reviewed. The published version of this Preprint is available: https://doi.org/10.1111/bre.12550. This is version 2 of this Preprint.

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Authors

Oliver B. Duffy, Timothy Dooley, Michael Hudec, Naiara Fernandez, Christopher Aiden-Lee Jackson , Juan I. Soto

Abstract

Shortening styles in salt-influenced basins can vary markedly, with the volume and distribution of salt prior to shortening being a key control. Here we use a suite of physical models to examine styles of thin-skinned regional shortening in settings where the pre-shortening structure comprised minibasins surrounded by salt (‘isolated-minibasin’ provinces). Our models show that the high volume of mechanically-weak salt localizes lateral regional shortening, with shortening inducing salt flow towards the foreland that subsequently contributes to three key processes - translation, tilting and rotation of minibasins. First, we demonstrate that the flowing salt pushes against minibasins, propelling them in the regional shortening direction. Minibasin translation is enhanced by fast-flowing salt streams and impeded by basal friction due to welding and base-salt buttresses. Second, we show how minibasin tilt directions and magnitudes vary spatially and temporally during regional shortening. Minibasins tilt away from zones of pressurized salt, the locations of which may shift due to changes in salt flow regimes. Tilt directions may also change as minibasins pivot on primary welds, or due to forces associated with minibasin collision. Third, minibasins can rotate around sub-vertical axes during regional shortening. We speculate that this rotation is caused by a combination of: i) traction imparted on the minibasin boundary by differential horizontal flow of adjacent salt; and ii) pivoting on primary and secondary welds. We synthesize our results in a series of 3-D conceptual models, before we compare and contrast regional shortening styles and processes in salt-influenced basins with different pre-shortening salt configurations. Our findings contribute to the understanding of the geometry and kinematics of shortened salt basins, as well as a deeper understanding of the tectono-stratigraphic evolution of minibasins.

DOI

https://doi.org/10.31223/osf.io/n59z4

Subjects

Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure

Keywords

salt tectonics; minibasins; shortening; fold-and-thrust belts; welding; structural style

Dates

Published: 2020-07-16 06:55

Last Updated: 2022-06-15 08:56

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License

CC BY Attribution 4.0 International

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