A complete structural model and kinematic history for distributed deformation in the Wharton Basin
A complete structural model and kinematic history for distributed deformation in the Wharton Basin
The equatorial eastern Indian Ocean hosts a diffuse plate boundary, where widespread deformation accommodates the relative motion between the Indian, Australian and Capricorn sub-plates. We integrate IODP Expedition 362 borehole data, which for the first time provides an accurate, ground-truthed chronostratigraphy of the sedimentary sequence east of the Ninety East Ridge (NER), with 2D seismic reflection profiles and multibeam bathymetry to assess the styles of faulting between the NER and the Sunda subduction zone, timing of activity and comparison with physical and rheological properties. We identify four distinct fault sets east of the NER in the northern Wharton Basin. N-S (350-010°) orientated faults, associated with the N-S fracture zones formed at the now extinct Wharton spreading centre, are still active and have been continuously active since at least 10 Ma. NNE- and WNW-trending fault fabrics develop between the fracture zones. The orientations and likely sense of displacement on these three sets of faults defines a Riedel shear system responding to ∼NNE-SSW left-lateral strike-slip activity at depth, demonstrated by the recent 2012 great intraplate earthquakes. We also find evidence of ∼NE-SW reverse faults, similar in style to E-W reverse faults observed west of the NER, where reverse faulting is more dominant. We show that the activity of this strike-slip system increased ca. 7-9 Ma, contemporaneous with reverse faulting and intraplate deformation west of the NER.
IODP, Indian Ocean, diffuse plate boundary, intraplate deformation
Stevens, Duncan, Eliott
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Mcneill, Lisa
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Henstock, Timothy
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Delescluse, Matthias
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Chamot-Rooke, Nicolas
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Bull, Jonathan
974037fd-544b-458f-98cc-ce8eca89e3c8
15 May 2020
Stevens, Duncan, Eliott
d8a1aedd-186d-47d5-a849-6c39fc9f0a1d
Mcneill, Lisa
1fe6a1e0-ca1a-4b6f-8469-309d0f9de0cf
Henstock, Timothy
27c450a4-3e6b-41f8-97f9-4e0e181400bb
Delescluse, Matthias
54e1642b-965b-46a4-a87e-10174c21cba9
Chamot-Rooke, Nicolas
4ff9e1d0-d0d6-46c5-9ca9-c7b15377a209
Bull, Jonathan
974037fd-544b-458f-98cc-ce8eca89e3c8
Stevens, Duncan, Eliott, Mcneill, Lisa, Henstock, Timothy, Delescluse, Matthias, Chamot-Rooke, Nicolas and Bull, Jonathan
(2020)
A complete structural model and kinematic history for distributed deformation in the Wharton Basin.
Earth and Planetary Science Letters, 538, [116218].
(doi:10.1016/j.epsl.2020.116218).
Abstract
The equatorial eastern Indian Ocean hosts a diffuse plate boundary, where widespread deformation accommodates the relative motion between the Indian, Australian and Capricorn sub-plates. We integrate IODP Expedition 362 borehole data, which for the first time provides an accurate, ground-truthed chronostratigraphy of the sedimentary sequence east of the Ninety East Ridge (NER), with 2D seismic reflection profiles and multibeam bathymetry to assess the styles of faulting between the NER and the Sunda subduction zone, timing of activity and comparison with physical and rheological properties. We identify four distinct fault sets east of the NER in the northern Wharton Basin. N-S (350-010°) orientated faults, associated with the N-S fracture zones formed at the now extinct Wharton spreading centre, are still active and have been continuously active since at least 10 Ma. NNE- and WNW-trending fault fabrics develop between the fracture zones. The orientations and likely sense of displacement on these three sets of faults defines a Riedel shear system responding to ∼NNE-SSW left-lateral strike-slip activity at depth, demonstrated by the recent 2012 great intraplate earthquakes. We also find evidence of ∼NE-SW reverse faults, similar in style to E-W reverse faults observed west of the NER, where reverse faulting is more dominant. We show that the activity of this strike-slip system increased ca. 7-9 Ma, contemporaneous with reverse faulting and intraplate deformation west of the NER.
Text
Stevens_el_al-Structure_of_the_Wharton_Basin
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More information
Accepted/In Press date: 9 March 2020
e-pub ahead of print date: 23 March 2020
Published date: 15 May 2020
Additional Information:
Funding Information:
This research used data provided by the International Ocean Discovery Program (IODP) ( www.iodp.org/access-data-and-samples ) and was supported by the Natural Environmental Research Council [grant numbers NE/P012817/1 and NE/L002531/1 ]. We thank the JOIDES Resolution crew, IODP technical team and science party for their contributions during Expedition 362. We also thank Dave Sanderson for useful discussions, the two anonymous reviewers for their comments, which helped to improve this manuscript and editor Jean-Philippe Avouac.
Publisher Copyright:
© 2020 The Author(s)
Keywords:
IODP, Indian Ocean, diffuse plate boundary, intraplate deformation
Identifiers
Local EPrints ID: 438727
URI: http://eprints.soton.ac.uk/id/eprint/438727
ISSN: 0012-821X
PURE UUID: 9757984a-931d-4a15-b7b5-45b46d764825
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Date deposited: 23 Mar 2020 17:31
Last modified: 17 Mar 2024 05:24
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Contributors
Author:
Matthias Delescluse
Author:
Nicolas Chamot-Rooke
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