The National Geochemical Survey of Australia (NGSA) project was launched in 2007 as part of the Australian Government's Energy Security Initiative. Knowledge of the concentrations and distributions of chemical elements in the near-surface environment, used in combination with other datasets, can contribute to making exploration for energy and mineral resources more cost-effective and less risky. As a spin-off, the multi-element dataset can also have applications in environmental fields. During precursor pilot projects, various sampling media, grain-size fractions and analytical methods were tested. It emerged that catchment outlet sediments (from either overbank or floodplain landforms, or from similar low-lying settings) were an ideal sampling medium found across Australia. These sediments are well-mixed composites of the dominant rock and soil types of a catchment, and are typically fine-grained. Results from the pilot projects indicated that catchment outlet sediments could reflect geochemical signatures from basement and mineralisation, even through thick transported overburden. Building on these methods, the NGSA project targeted catchment outlet sediments as a uniform sampling medium. A shallow (0-10 cm) and a deeper (~60-80 cm) sediment sample was collected at the outlet of 1186 catchments covering ~80% of the country. Sampling was carried out by State and Northern Territory geoscience agencies following protocols described in the Field Manual and practiced during in-field training with Geoscience Australia project staff. All sampling equipment (augers, shovels, etc.) and consumables (bags, labels, etc.) were provided centrally. Dry and moist Munsell colours, soil pH, digital photographs, site information and GPS coordinates were recorded in the field. .../...

Many countries around the world have carried out national-scale geochemical surveys, providing important information on the natural concentration of chemical elements and compounds in the near-surface regolith. Resultant data and information layers have been put to a multitude of uses: Identifying targets for mineral exploration; improving land-use management and environmental policy development; and providing information for studies into the health and well-being of humans, animals and plants. Between 2003 and 2007 several regional geochemical pilot surveys were conducted in Australia. These surveys have identified element concentrations that relate to soil acidity and salinity, reflect known areas of mineralisation, or are above or below national and international agricultural soils guidelines. In 2007, following on from the success of the pilot surveys, Geoscience Australia established Australia's first national geochemical survey. Working in collaboration with State and Territory geoscience agencies, ultra low-density sampling of catchment outlet (overbank) sediments from two depths (0-10 cm below surface and from a 10 cm interval at around 60-90 cm) has commenced. Samples are prepared and split into <2 mm and <75 mm fractions before both are analysed using a wide range of analytical techniques including XRF and ICP-MS. To date, 80% of samples have been collected and 50% of the total number of samples have been analysed. Ultimately the National Geochemical Survey of Australia project will rapidly and cost-effectively deliver a national geochemical atlas and a new dataset that will underpin positive outcomes in the exploration and mining, environmental, agricultural, forestry, recreational, and health and well-being sectors.

Map(s) of Sr (strontium) concentration (Total content, Aqua Regia soluble content, and/or Mobile Metal Ion soluble content) in Top Outlet Sediment (TOS) and/or Bottom Outlet Sediment (BOS) samples, dry-sieved to <2 mm and/or <75 um grain size fractions. Source: The Geochemical Atlas of Australia (Caritat and Cooper, 2011)

Map(s) of Ba (barium) concentration (Total content, Aqua Regia soluble content, and/or Mobile Metal Ion soluble content) in Top Outlet Sediment (TOS) and/or Bottom Outlet Sediment (BOS) samples, dry-sieved to <2 mm and/or <75 um grain size fractions. Source: The Geochemical Atlas of Australia (Caritat and Cooper, 2011)

Map(s) of Ho (holmium) concentration (Total content, Aqua Regia soluble content, and/or Mobile Metal Ion soluble content) in Top Outlet Sediment (TOS) and/or Bottom Outlet Sediment (BOS) samples, dry-sieved to <2 mm and/or <75 um grain size fractions. Source: The Geochemical Atlas of Australia (Caritat and Cooper, 2011)

This record describes digital data compilation product, where several individual items are grouped for delivery on single CD-ROM. Content and number of items included in the compilation package can vary, depending on size of the individual items. The contents of this CD-ROM are as follows: Catalog # Title 21285 Bathurst regolith landforms, 1:250 000 scale map 250k 30631 Cobar regolith landforms. A regional overview of regolith landforms 500k 25238 Cootamundra, interpreted geology based on geophysics and previous geological mapping 250k

No abstract available

Map(s) of Cs (caesium) concentration (Total content, Aqua Regia soluble content, and/or Mobile Metal Ion soluble content) in Top Outlet Sediment (TOS) and/or Bottom Outlet Sediment (BOS) samples, dry-sieved to <2 mm and/or <75 um grain size fractions. Source: The Geochemical Atlas of Australia (Caritat and Cooper, 2011)

The Thomson regolith geochemical survey is a multi-agency collaborative project that aims to provide mineral explorers in northwestern NSW with an internally consistent background geochemical dataset. Transported regolith was sampled at 99 catchment outlet sites from the surface and at depth. Element concentrations were determined using XRF and ICP-MS on <75 µm and <180 µm fractions. Preliminary results suggest that higher concentrations of Cu, Sb and Pb are proximal to known mineralisation (1) in the west near outcrop of the Curnamona Province; (2) at the junction of the Koonenberry, Thomson and Lachlan crustal elements; and (3) in the east near the Cobar Basin. Low concentrations in many ore elements coincide with areas of thicker Great Australian Basin cover with no known mineral occurrences. Several anomalous concentrations occur well away from known mineralisation and deserve further investigation. Recent drilling near such an anomaly discovered sulfide mineralisation. Bedrock signatures are clearly detectable in some regolith geochemical patterns.

Map(s) of Re (rhenium) concentration (Total content, Aqua Regia soluble content, and/or Mobile Metal Ion soluble content) in Top Outlet Sediment (TOS) and/or Bottom Outlet Sediment (BOS) samples, dry-sieved to <2 mm and/or <75 um grain size fractions. Source: The Geochemical Atlas of Australia (Caritat and Cooper, 2011)