Layer parallel stretching? Characterising magnetic and pore-fabric styles at a rifted continental margin: New insights from the Otway Ranges, Australia

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dc.contributor.authorBurgin, H.B.
dc.contributor.authorRobion, P.
dc.contributor.authorAmrouch, K.
dc.date.issued2021
dc.descriptionAvailable online 25 June 2021
dc.description.abstractThis study presents the first analysis of the anisotropy of magnetic susceptibility (AMS) coupled with anisotropy of P-wave velocity (APV) in sedimentary rocks from a passive continental margin. In the Otway Ranges, Australia, the Lower Cretaceous sediments deposited during a period of subsidence and structural quiescence display triaxial-magnetic fabrics typical of extensional deformation. The extensional interpretation from AMS is also supported by the orientation of the pore fabric measured using APV. The inferred extensional azimuths from both AMS and APV analyses are in good agreement with axes for renewed Late Cretaceous rifting and the continental break up of Gondwana, a period of structural evolution characterised by abnormally-high levels of paleostress in the Otway Basin. Predicated on this we introduce the concept of layer parallel stretching (LPSt), a process that describes pore-scale structuring representative of the first phase of extensional deformation during periods of intense tectonic extension, in this case the LPSt was oriented NE-SW. These extensional structural fabrics in the Otway Basin were preserved during NE-SW oriented basin inversion, a process that involved reactivation of the local detachment, the partitioning of strain, and low levels of coupling between the basement and the cover. The results highlight the applicability of AMS and APV for characterising rock anisotropy in sedimentary basins at continental margins and have distinct outcomes with respect to the structural framework of the study area in the Otway Ranges.
dc.description.statementofresponsibilityHugo B. Burgin, Philippe Robion, Khalid Amrouch
dc.identifier.citationTectonophysics, 2021; 815:1-21
dc.identifier.doi10.1016/j.tecto.2021.228975
dc.identifier.issn0040-1951
dc.identifier.issn1879-3266
dc.identifier.orcidAmrouch, K. [0000-0001-7180-3386]
dc.identifier.urihttp://hdl.handle.net/2440/131559
dc.language.isoen
dc.publisherElsevier
dc.relation.granthttp://purl.org/au-research/grants/arc/DP160101158
dc.relation.granthttp://purl.org/au-research/grants/arc/DP190103457
dc.rights© 2021 Elsevier B.V. All rights reserved.
dc.source.urihttps://doi.org/10.1016/j.tecto.2021.228975
dc.titleLayer parallel stretching? Characterising magnetic and pore-fabric styles at a rifted continental margin: New insights from the Otway Ranges, Australia
dc.typeJournal article
pubs.publication-statusPublished

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