Authors / CoAuthors
Draper, J.J. | Jensen, A.R.
Abstract
Lake Frome, a large playa in southeast South Australia, lies at the centre of an internal drainage basin. Sediments and brines in the lake were studied to determine if the movement of fluids and sediments into an internal drainage basin in an arid environment could concentrate metal ions through evaporation or the action of sulphate reducing bacteria. Secondary objectives were the study of continental brines, playa sedimentation, and mound springs. Stratigraphic analysis based on samples from a series of shallow auger holes shows that over the last 17000 years medium to fine sand accumulated on the margins of the lake and mud in the centre. The sediment has issued from streams entering the lake on all but the eastern sides, mainly in delta fans. Three informal stratigraphic units were recognised - upper and lower sandy units, and a muddy unit which is regarded as a lateral equivalent. A salt crust up to 20 cm thick overlies the clastic sediment in the centre of the lake. At the time of the survey about 10 per cent of the lake was covered with water. Both surface and sub-surface waters are hypersaline (26 to 34 percent) and characterized by high concentrations of sodium and chloride ions. The major ions have probably been derived from marine sediments. No enrichment of minor elements was detected in the brines, but lead appears to be leached from the sediments as soluble chloride complexes. Clastic sediments from the lake have been analysed for major and minor elements. Statistical analysis of the results indicates that the upper and lower sands are geochemically similar and that they differ from the muds, which have higher concentrations of organic carbon and certain minor elements. There is no evidence of concentration of metal ions although manganese appears to have been concentrated on the surface of the lake by algae. Mound springs in the northeastern part of the lake differ from those of the southeast in composition of the mound and the water. The composition of the water reflects mixing of artesian water with lake brines.
Product Type
document
eCat Id
80870
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
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2601
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Keywords
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- GA PublicationJournal
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- SA
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_External
Publication Date
1976-01-01T00:00:00
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unknown
Topic Category
geoscientificInformation
Series Information
BMR Journal of Australian Geology and Geophysics 1:2:83-104
Lineage
Unknown
Parent Information
Extents
[-31.5, -29.0, 138.0, 141.0]
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Spatial Resolution
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