Authors / CoAuthors
Hackney, R. | Watts, A.B. | Johnston, S.
Abstract
Basins on the western margin of Australia are both well explored (e.g. North West Shelf) or under-explored frontier basins (e.g. Perth Basin). For many of these basins, knowledge of basement and crustal structure is limited. To provide new insight into these fundamental features of a continental margin, we present the results of process-oriented gravity modelling applied to basins both with (North West Shelf) and without (Perth Basin) constraints on crustal structure. Process-oriented gravity modelling is a method that considers the rifting, sedimentation and magmatic processes that led to the present-day gravity field. By back-stripping the sediment load under different assumptions of isostasy (i.e. range of flexural rigidities), rift-related crustal structure can be inferred. When the rift and sedimentation gravity anomalies are combined and compared to observed free-air gravity, insight into the presence of magmatic underplating, the location of the continent-ocean boundary and the thermal history of a margin can, amongst other factors, be gained. Initial modelling suggests that the Perth Basin maintained a relatively low flexural rigidity throughout its history (effective elastic thickness ~5 km), which may reflect the prevalence of transtensional deformation during Late Jurassic-Early Cretaceous break-up between Australia and Greater India. However, constraining elastic thickness in the Perth Basin is made difficult by uncertainties in resolving the total sediment thickness (particularly in outboard parts of the basin) and crustal structure. Such uncertainties are less of an issue for some North West Shelf basins where seismic refraction data enhance the interpretation of abundant seismic reflection data.
Product Type
nonGeographicDataset
eCat Id
73370
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
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2601
Australia
Keywords
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- External Publication
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- sedimentary basins
- ( Theme )
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- gravity
- ( Theme )
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- model
- ( Theme )
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- continental margins
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
Publication Date
2012-01-01T00:00:00
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