Authors / CoAuthors
Tan, K.P. | Halas, L. | Magee, J. | Gibson, D.L. | Clarke, J.D.A.
Abstract
In the Lower Darling Valley (LDV) Quaternary fluvial sequence, multiple scroll-plain tracts (Coonambidgal Formation) are incised into higher, older and more featureless floodplain terrain also underlain by lateral-accretion sediment (Menindee Formation). Bordering the floodplain is the Woorinen Formation regional dune field, which overlies lateral-accretion fluvial sediment of the Willotia beds. Also present are the Menindee Lakes lake-floor sediment and lunettes. Due to the subtlety in surface expression and migration of dunes across the floodplain, the boundary between Menindee Formation and Willotia beds may be difficult to discern. In this case, AEM data, acquired over an area of 7,500 sq km and validated by 100 new boreholes, is used to identify and characterise the stratigraphic units. AEM data was generated as both cross sections along individual flight line and depth slices with increasing thickness with depth, ranging from 0.5m to 11m. From the depth slices and borehole lithological information, the thicknesses of the near surface overbank-mud drape were determined and mapped. Conductive and resistive patterns resembling scroll-bar and abandoned channel fills were identified at 13m to 15.6m depths beneath the featureless floodplain. Large sub-surface tracts of resistive features extending between the Darling and the Talyawalka scroll-plains on the surface help establish the distribution of palaeo-river tracts beneath the floodplain. Towards the south, strand patterns associated with the marginal marine Loxton-Parilla Sands were identified.
Product Type
nonGeographicDataset
eCat Id
74809
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
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2601
Australia
Keywords
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- External PublicationAbstract
- ( Theme )
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- geomorphology
- ( Theme )
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- AEM
- ( Theme )
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- sedimentology
- 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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