Authors / CoAuthors
Magee, J.W. | Gibson, D.L. | Clarke, J.D.A. | Halas, L. | Tan, K.P. | Pain, C.F.
Abstract
Multiple new geophysical (airborne electromagnetics, borehole gamma and NMR), geospatial (LiDAR), sonic drilling and geochronological datasets have been used to map and resolve the nature of Quaternary fluvial deposition in the Lower Darling Valley (LDV), NSW. The LDV Cenozoic sequence contains Paleogene and Neogene shallow marine, fluvial and shoreline sediments overlain by Quaternary lacustrine, aeolian and fluvial units. In the LDV Quaternary fluvial sequence, multiple scroll-plain tracts are incised into higher, older more featureless floodplains. Prior to this study, these were respectively correlated to the Coonambidgal and Shepparton Formations of the Riverine Plain in the eastern Murray Basin and associated with the subsequently discarded Prior Stream/Ancestral River chronosequence of different climatically controlled depositional styles. In contrast to that proposition, we ascribe all LDV Quaternary fluvial deposition to lateral-migration depositional phases of one style, though with more variable stream discharges and channel and meander-scroll dimensions. Successively higher overbank-mud deposition through time obscures scroll traces and provides the main ongoing morphologic difference. A new morphostratigraphic unit, the Menindee Formation, refers to the mostly older and higher floodplain sediments, where scroll traces are obscured by overbank mud which continues to be deposited by the highest modern floods. Younger inset scroll-plain tracts, with visible scroll-plain traces, are still referred to the Coonambidgal Formation. Another new stratigraphic unit, the Willotia beds, refers to even older fluvial sediments, now above modern floodplain levels and mostly covered by aeolian sediments. This work provides important insights into hydrogeological processes and the nature of Australian Quaternary fluvial deposition.
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nonGeographicDataset
eCat Id
73630
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
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- External PublicationAbstract
- ( Theme )
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- hydrogeology
- ( Theme )
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- groundwater
- ( Theme )
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- geochronology
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
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2012-01-01T00:00:00
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[-33.159278, -31.814781, 141.958071, 143.284724]
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