Authors / CoAuthors
Cathro, D.L. | Karner, G.D.
Abstract
Seismic sequence analysis across the Northern Carnarvon basin of the northwest Australian margin has been combined with a kinematic and flexural model for the deformation of the lithosphere and palaeobathymetric analysis of benthic foraminifera to define the history, distribution and magnitude of inversion within the Dampier Sub-basin during the Cretaceous and Tertiary. The large palaeo-water depths (>1000 m) developed across the outer margin in the late Oligocene-Miocene questions the results from earlier well-based backstripping studies. This accommodation was created by a combination of thermal subsidence engendered primarily by Tithonian-Valanginian extension and continental break-up and sediment loading associated with the progradation of Neogene clinoforms. Discrete inversion events characterize the Santonian, late early Miocene, middle Miocene, late Miocene, latest Miocene, and Plio-Pleistocene of the Northern Carnarvon basin. Compression-induced inversion creates and destroys accommodation space at different spatial wavelengths compared with thermal subsidence, sediment loading and eustatic variations and thus can be spatially separated. While brittle deformation in the upper crust results in relatively short-wavelength uplift, the flexural response to this tectonic loading produces a longer-wavelength regional subsidence adjacent to the inversion anticline. In general, the flexural component is negligible. Inversion tends to be focused along pre-existing rift fault systems. However, the spatial distribution of inversion varied through time, with Cretaceous inversion concentrated along the northeast-southwest oriented Rankin, Madeleine, and Rosemary trends while the locus of Miocene inversion was located ~20 km northwest of the Rosemary Trend. Clearly, different fault zones were involved in the inversion process at different times. We surmise that intraplate stresses generated from the readjustment of the Indo-Australian plate were a possible mechanism for Santonian inversion. Tertiary inversion, interpreted to have commenced in the middle Miocene (~17 Ma), continued to occur through to the Plio-Pleistocene. The onset and continued compression is interpreted to be related to the Australian/Indonesian continent-continent collision. Total shortening of the lithosphere during the Santonian and Tertiary was modelled to be 2.6 and 0.16 km, respectively.
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nonGeographicDataset
eCat Id
41197
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
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Keywords
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- External PublicationScientific Journal Paper
- ( Theme )
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- structural geology
- ( Theme )
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- sequence stratigraphy
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- AU-WA
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
Publication Date
2002-09-30T00:00:00
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geoscientificInformation
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[-22.0, -18.0, 113.0, 119.0]
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