Science to lift veil on ancient valleys
16 November 2011
An unprecedented application of geoscientific disciplines and tools is helping in the search for potential water resources in some of Australia's driest regions.
Scientists are using the airborne electromagnetic and radiometric imagery, high-resolution one second digital elevation model data and processed satellite imagery in the search for ancient waterways, or paleovalleys in Western Australia, South Australia and the Northern Territory. The work is being carried as part of a groundwater project funded by the National Water Commission .
The palaeovalley sediments were deposited when the climate was a lot wetter and although the rivers themselves may have disappeared, the remaining sediments can contain important groundwater resources. These aquifers frequently provide the only available water for remote indigenous communities, the pastoral industry and mining activities as well as arid zone ecosystems.
Geoscience Australia researcher, Dr Pauline English, said that in the Paterson region of the Great Sandy Desert where palaeovalleys are a legacy of deglaciation and are buried beneath sand dunes, airborne electromagnetic imagery has delineated the ancient valley systems in three dimensions.
"This is helping to resolve long-standing questions about palaeo-flow directions, confluences, divides and watersheds, as well as prospectivity for groundwater resources," Dr English said.
"Elsewhere, the high-resolution digital elevation model data has been processed to reduce the influence of sand dune topography to reveal the underlying palaeovalley networks. At the same time, processed satellite imagery has provided information on mineral and moisture contents in the landscape, giving a clearer picture of the location and composition of palaeovalleys and shallow water tables," she said.
"The innovative use of this array of geoscience disciplines has allowed Geoscience Australia to help develop a better understanding of the precious groundwater resources in arid parts of Australia and provide benefits for remote communities and the mining and exploration industry," Dr English said.
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