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Influence of variable decoupling between vertically separated fault populations on structural inheritance – The Laminaria High, NW Shelf of Australia

Phillips, Thomas B.; McCaffrey, Ken; Magarinos, Luke

Influence of variable decoupling between vertically separated fault populations on structural inheritance – The Laminaria High, NW Shelf of Australia Thumbnail


Authors

Thomas B. Phillips

Luke Magarinos



Abstract

When extension events are greatly separated in time, older faults may be buried and stratigraphically separated from newly developing faults at shallower depths. During rifting, the buried structures may reactivate and propagate upwards to be expressed within the shallow system. The degree of linkage between structural levels determines the influence that the deeper structures can exert over the geometry and evolution of the incipient fault system. In this study we use 3D seismic reflection data to examine how a deep fault population across the Laminaria High, NW shelf of Australia influences the development of a younger fault system at shallow depths. These fault populations are non-parallel and decoupled across a mechanically weak interval. The majority of shallow faults are not linked to those at depth. However, the reactivation and upward propagation of some of the deeper faults produce anomalously oriented structures at shallow depths, hard-linked to the deeper structures. One fault in particular shows along-strike variability, with the deep segment reactivated and present at shallow depths in the west. To the east, the shallow and deep fault segments become decoupled across the mechanically weak interval, although some soft-linkage and strain transfer still occurs. We suggest that this switch in the degree of coupling along the fault is due to the geometry of the deeper structure, with the transition corresponding to a prominent relay ramp. We show how the geometry of a deeper fault may affect its propensity to reactivate during subsequent extensional events, ultimately affecting the degree of structural inheritance that is expressed within younger, shallower fault populations.

Citation

Phillips, T. B., McCaffrey, K., & Magarinos, L. (2022). Influence of variable decoupling between vertically separated fault populations on structural inheritance – The Laminaria High, NW Shelf of Australia. Basin Research, 34(1), 440-456. https://doi.org/10.1111/bre.12626

Journal Article Type Article
Acceptance Date Oct 14, 2021
Online Publication Date Nov 10, 2021
Publication Date 2022-02
Deposit Date Dec 16, 2021
Publicly Available Date Dec 16, 2021
Journal Basin Research
Print ISSN 0950-091X
Electronic ISSN 1365-2117
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 34
Issue 1
Pages 440-456
DOI https://doi.org/10.1111/bre.12626
Public URL https://durham-repository.worktribe.com/output/1218715

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Publisher Licence URL
http://creativecommons.org/licenses/by/4.0/

Copyright Statement
© 2021 The Authors. Basin Research published by International Association of Sedimentologists and European Association of Geoscientists and Engineers and John Wiley & Sons Ltd.

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.





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