'Beneath the Sand of the Tanami Desert'
‘Beneath the sand of the Tanami Desert’ ARGA 2018, Wallaroo, SA Nadir de Souza Kovacs Ngururrpa program The program area covers Parna Ngururrpa people invited GSWA to the traditional land of the survey their country aiming to stimulate Parna Ngururrpa People in mineral exploration a remote part of the Tanami Desert in WA • gravity survey • regolith landform map 1:250 000 • geochemical soil sampling Geomorphology The landscape is flat, with variably weathered, low lying rock outcrops, and extensive eolian dune fields, sandplain NW-SE Stansmore Range, max 510m asl –to the west lies the and lacustrine - playa terrain. Canning Plain and the Great Sandy Dessert Semi-arid, sandy soils, spinifex, E-W longitudinal dunes and spinifex sparse small shrubs and covered interdunes scattered small trees Salt lakes and Neoproterozoic sandstone ridges covered by silcrete veneers are common to the East Regolith sampling GSWA 2015 regional regolith geochemistry program collected 637 soil samples at 5 km grid, up to 90 cm depth. Geology Phanerozoic Canning Basin -Eastern margin –sandstone, siltstone, minor conglomerate, coal, limestone ProterozoicCentralia Murraba Basin –sandstone, wacke, conglomerate, siltstone, shale, limestone, dolomite, chert, and glauconitic sandstone Proterozoic NAC -N border Granites-Tanami Orogen; granitic and S border Arunta Orogen; meta-igneous and meta-sedimentary Regional faults and linear structures Stansmore Fault Minor linear structures Beneath the sand…but how far beneath… At the Surface Surface to 30 –45 cm deep Near surface –deeper (?) (1 m to 90 m) Orthophotos, Digital Elevation Models Radiometric KTU, LANDSAT AGSO ratios Magnetic VD1, Gravity ….depends on the information provided by… Direct observation 2015 sampling –rock and residual regolith at less than 1 m deep Geophysical image -expression of regolith Inference from shallow stratigraphic holes in the neighbouring area (regolith thickness 1m to 90m) top 30-45 cm of the surface.
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