A major challenge that bedrock mineral exploration faces in many parts of South Australia is exploring efficiently and effectively through extensive and thick regolith cover. The SGRV regolith map aims to provide a broad-scale framework for...

A major challenge that bedrock mineral exploration faces in many parts of South Australia is exploring efficiently and effectively through extensive and thick regolith cover. The SGRV regolith map aims to provide a broad-scale framework for guiding geochemical prospecting for a wide range of minerals and materials, as a basis for guiding mineral exploration, and to provide a useful dataset for addressing other land use issues like groundwater.

More +

Mapping was based on the 1:100 000-scale geology layer (SARIG) using the RTMAP scheme (after Pain et al, 2007). The regolith polygon linework was newly compiled for the YARDEA and PORT AUGUSTA 1:250,000 scale map sheets using ArcGIS 10.1. For each...

Mapping was based on the 1:100 000-scale geology layer (SARIG) using the RTMAP scheme (after Pain et al, 2007). The regolith polygon linework was newly compiled for the YARDEA and PORT AUGUSTA 1:250,000 scale map sheets using ArcGIS 10.1. For each regolith polygon ten attributes were captured during the mapping process including regolith materials and landforms name, description, RTMAP code and map symbol, as well as the TI (transported or in-situ) and RED (residual-erosional-depositional) scheme. Mapping and map compilation was based on a variety of data, with the 1:100,000 State geology datasets, Landsat TM5 and ETM7 images, 1sec and 3sec DEM, radiometrics, Google Earth (3D view) and existing CRCLEME regolith maps for the area representing the key datasets. Spatial accuracy and linework detail was in parts improved in comparison to the 100k State geology dataset, due to the availability of higher resolution images. It should be noted that the SGRV regolith map represents the surface distribution and expression of the regolith and it does not include any information about regolith thickness, stratigraphy and age. Very limited information about bedrock weathering intensity was available from existing datasets. Therefore, outcropping bedrocks has only been subdivided into several map units based on their geological province, lithology and stratigraphy. Material that has a close association with the underlying bedrock and has not experienced a large degree of transport has been mapped as residual material.
Piggyback codes have been used for some polygons where it was known that different regolith overlies other regolith material. 
As mineralisation in regolith is often related to intense induration, e.g. uranium and gold in calcretes, induration of regolith material has also been mapped on the SGRV Regolith Map. Information about induration has been extracted from the existing 1:100 000-scale geology data layer in SARIG.
Positional accuracy:Nominal scale 1:250 000 highly variable since the map was digitised at various scales. For the regolith layer the polygon linework was digitised at scales between 1:25k and 1:250k.
Attribute accuracy:Variable due to regolith attributes being derived from geological and regolith mapping work done by a series of authors based on the 1:250,000-scale geological map series, complemented by the 1:2,000,000 State Geology Map and existing information from various datasets such as geology, topographic, geophysical and multispectal and hyperspectral remote sensing data. The attributes were assessed against current regolith science mapping codes and authority tables and were modified and standardised with current information.
Logical consistency:Several geoscientists visually inspected the finished dataset to make sure the attributes were accurate and the data were consistent spatially with current scientific information.
Completeness: Complete for South Australia, subject to update.

More +