Timing of extension-related uplift and erosion in the Dampier Sub-basin

Sarah Vivien Kerr

    Research output: ThesisMaster's Thesis

    254 Downloads (Pure)

    Abstract

    This study presents a structural analysis and Mesozic tectonostratigraphic history for the
    Dampier Sub-basin, located in the Northern Carnarvon Basin on the North-West Shelf of
    Australia. Regional unconformities, seismic stratigraphic packages and rift-related
    extensional structures were interpreted from the Demeter 3D seismic survey, integrated with
    biostratigraphic ages and lithostratigraphy from exploration well data. Structural analysis
    identified four populations of Triassic-aged syn-rift extensional faults; (1) NNE-striking
    basin-oblique faults comprising the NE-oriented Rankin Trend, (2) NE-striking basinparallel
    faults comprising the Madeleine Trend, (3) southern NE-striking sinuous basinparallel
    faults, and (4) N/S-striking oblique-normal faults. A 3D fault model was produced
    that reveals the syn-rift topography of the sub-basin in the Mesozoic. Fault orientations and
    geometries indicate coeval evolution of the Mesozoic basin fault architecture, driven by
    WNW-oriented oblique extension focused on reactivated Paleozoic rift structures. All fault
    populations are linked to form a greater fault system accommodating extensional strain
    across the basin. Six seismic stratigraphic packages were interpreted, separated by regional
    unconformities. These packages correspond to changes in relative sea level, sedimentation
    rates and accommodation associated with the progressive breakup of Gondwana and allow
    correlation of basin-scale events to plate-scale tectonic events. Five phases of Mesozoic
    rifting were distinguished; (1) Triassic pre-rift thermal subsidence and sedimentation, (2)
    Upper Triassic rifting establishing the structural architecture of the sub-basin, forming the
    Lewis and Kendrew Troughs, Rankin Platform and Madeleine Trend, (3) Upper Jurassic to
    Lower Cretaceous rifting following a major erosional event, punctuated by minor inversion,
    (4) Cretaceous post-rift thermal sag and conformable sedimentation of dominantly carbonate
    successions, (5) Cenozoic passive margin settling with prograding carbonate sedimentation.
    Original languageEnglish
    QualificationMasters
    Awarding Institution
    • The University of Western Australia
    DOIs
    Publication statusUnpublished - 2016

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