Authors / CoAuthors
Cathro, D.L. | Austin, J.A., Jr. | Moss, G.D.
Abstract
We combine two- and three-dimensional seismic stratigraphic interpretation with paleobathymetric analysis from benthic foraminifera to understand the genetic significance of prominent seismic discontinuity surfaces typically mapped as "sequence boundaries" and "flooding surfaces" in the late Paleogene-early Neogene Northern Carnarvon Basin. The progradational succession, dominated by heterozoan carbonate sediments, is divided into five northwest-prograding clinoformal sequences and 19 sub-sequences. Clinoform fronts progress from smooth to highly dissected, with intense gullying apparent only after the mid Miocene optimum. Once initiated, gullies become the focus for sediment distribution across the front. Bottomsets remain relatively sediment-starved without the development of aprons on the lower slope and basin. Small-scale variability suggests heterogeneous sediment dispersal through the slope conduits. Along-strike sediment transport superimposed on progradation changes from south-directed in the late Oligocene to north-directed in the late mid-Miocene suggesting a major reorganization of circulation in the southeastern Indian Ocean. Prominent seismic discontinuity surfaces represent both intervals of shallow paleo-water depth and flooding of the shelf. Partial exposure of the shelf indicated by karst morphology is coeval with middle to outer neritic paleo-water depths on the outer shelf. Rather than build to sea-level, progradation occurs with shelf paleo-water depths at the clinoform rollover >100 m. Therefore, in the Northern Carnarvon Basin onlap onto the clinoform front is not coastal and the sensitivity of the clinoforms to sea-level changes is muted.
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nonGeographicDataset
eCat Id
47376
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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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- sequence stratigraphy
- ( Theme )
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- carbonate
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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
2003-01-01T00:00:00
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geoscientificInformation
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[-22.0, -18.0, 113.0, 119.0]
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