Authors / CoAuthors
Cathro, D.L. | Austin, J.A., Jr. | Karner, G.D. | Moss, G.
Abstract
Two- and three-dimensional (2D and 3D) seismic stratigraphic interpretation, palaeobathymetric analysis from benthic foraminifera, and 2D forward tectonic modelling are combined to understand the genetic significance of prominent seismic discontinuity surfaces typically mapped as ?sequence boundaries? and ?flooding surfaces?, and their intervening sequences. Integration of these data has allowed interpretation of the Tertiary, heterozoan (i.e., non-photozoan) carbonate-dominated succession detailing the evolution of five prograding clinoformal sequences (2-5 m.y. duration), and 19 sub-sequences (<0.5-1 m.y. duration), along the Rankin Trend. Variations in accommodation space as modelled across the Dampier Sub-basin using 2D kinematic and flexural modelling are the combined result of synrift and postrift thermal subsidence, inversion and eustatic variations. The major observations and implications of this study are: ? Onlap onto the clinoform front of primary mappable surfaces is submarine with minimum estimated palaeo-water depths > 100 m at the shelf edge. Exposure surfaces identified in the middle Miocene are seismically less prominent, with potential karstification identified 6-8 km inboard of shelf edges. ? Systems tracts could not be consistently identified in the progradation-dominated succession. Lowstand basin-floor fans/aprons and transgressive systems tracts are largely absent on the seismic scale, resulting in downlap directly onto sequence boundaries. ? Linear, 30-80 km along strike, two-dimensional mapped sequences, are the integration of local sedimentary lobes up to 10 km in diameter. ? Canyon development may be controlled by inclination on gully failure walls rather than variations in sea level. Gully initiation is coincident with the mid-Miocene climatic Optimum. However, once established, erosion paths are maintained and enlarged by downslope sediment flows, derived from headward failure, regardless of proposed sea-level variations. ? The magnitude of inversion-related uplift is small, reaching a maximum of ~50-70 m at anticlinal crests focussed along the Rankin, Madeleine and Rosemary trends. Although this is of a similar scale to postulated eustatic variations that increase or decrease accommodation space across the entire margin, unconformities and onlap discontinuity surfaces related to these inversion structures are areally restricted.
Product Type
nonGeographicDataset
eCat Id
41198
Contact for the resource
Custodian
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Keywords
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- External PublicationAbstract
- ( Theme )
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- bathymetry
- ( Theme )
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- continental margins
- ( Theme )
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- palaeontology
- ( Theme )
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- sequence stratigraphy
- ( Theme )
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- structural geology
- ( Theme )
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- marine
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
Publication Date
2003-01-01T00:00:00
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geoscientificInformation
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Extents
[-22.0, -18.0, 113.0, 119.0]
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