Gregory, LC orcid.org/0000-0001-5525-5447, Mac Niocaill, C, Walker, RT et al. (2 more authors) (2018) Vertical axis rotation (or lack thereof) of the eastern Mongolian Altay Mountains: implications for far-field transpressional mountain building. Tectonophysics, 736. pp. 31-46. ISSN 0040-1951
Abstract
The Altay Mountains of Western Mongolia accommodate 10–20% of the current shortening of the India-Asia collision in a transpressive regime. Kinematic models of the Altay require faults to rotate anticlockwise about a vertical axis in order to accommodate compressional deformation on the major strike slip faults that cross the region. Such rotations should be detectable by palaeomagnetic data. Previous estimates from the one existing palaeomagnetic study from the Altay, on Oligocene and younger sediments from the Chuya Basin in the Siberian Altay, indicate that at least some parts of the Altay have experienced up to 39 ± 8° of anticlockwise rotation. Here, we present new palaeomagnetic results from samples collected in Cretaceous and younger sediments in the Zereg Basin along the Har-Us-Nuur fault in the eastern Altay Mountains, Mongolia. Our new palaeomagnetic results from the Zereg Basin provide reliable declinations, with palaeomagnetic directions from 10 sites that pass a fold test and include magnetic reversals. The declinations are not significantly rotated with respect to the directions expected from Cretaceous and younger virtual geomagnetic poles, suggesting that faults in the eastern Altay have not experienced a large degree of vertical axis rotation and cannot have rotated >7° in the past 5 m.y. The lack of rotation along the Har-Us-Nuur fault combined with a large amount of rotation in the northern Altay fits with a kinematic model for transpressional deformation in which faults in the Altay have rotated to an orientation that favours the development of flower structures and building of mountainous topography, while at the same time the range widens at the edges as strain is transferred to better oriented structures. Thus the Har-Us-Nuur fault is a relatively young fault in the Altay, and has not yet accommodated significant rotation.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2018 Elsevier B.V. This is an author produced version of a paper published in Tectonophysics. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Vertical axis rotation; Strike slip faults; Active faulting; Palaeomagnetism; Central Asian tectonics |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst of Geophysics and Tectonics (IGT) (Leeds) |
Funding Information: | Funder Grant number Royal Commission For Exhibition of 1851 No external ref |
Depositing User: | Symplectic Publications |
Date Deposited: | 24 Apr 2018 10:50 |
Last Modified: | 07 Apr 2019 00:38 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.tecto.2018.03.020 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:129978 |