Mike Caccetta

Satellite-derived mineral mapping and monitoring of weathering, deposition and erosion

The Earth’s surface comprises minerals diagnostic of weathering, deposition and erosion. The first continental-scale mineral maps generated from an imaging satellite with spectral bands designed to measure clays, quartz and other minerals were released in 2012 for Australia. Here we show how these satellite mineral maps improve our understanding of weathering, erosional and depositional processes in the context of changing weather, climate and tectonics. The clay composition map shows how kaolinite has developed over tectonically stable continental crust in response to deep weathering during northwardly migrating tropical conditions from 45 to 10 Ma. The same clay composition map, in combination with one sensitive to water content, enables the discrimination of illite from montmorillonite clays that typically develop in large depositional environments over thin (sinking) continental crust such as the Lake Eyre Basin. Cutting across these clay patterns are sandy deserts that developed <10 Ma and are well mapped using another satellite product sensitive to the particle size of silicate minerals. This product can also be used to measure temporal gains/losses of surface clay caused by periodic wind erosion (dust) and rainfall inundation (flood) events. The accuracy and information content of these satellite mineral maps are validated using published data.

Quantifying dust loading on mangroves using hyperspectral techniques

Dust derived from mining and handling of ore is a major problem in Australia and may be critical to the future viability of some resource industries. This paper reports the results of a study to derive quantitative measurements of dust loading on mangroves using remotely-sensed hyperspectral and proximal spectrometry techniques. The results show that it is possible to detect and quantitatively map the iron oxide dust distribution based on properly calibrated airborne and laboratory visible to short wave infrared (VNIR-SWIR) data. Operational techniques to derive accurate measurements of dust are necessary for the long-term management and monitoring of the environment at the iron ore handling facility at Port Hedland, WA.

Continent-scale mineral information from ASTER multispectral satellite data

Continent-scale digital maps of mineral information of the Earths land surface are now achievable using geoscience-tuned remote sensing systems. Multispectral ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) data and mineral information derived from it provide the opportunity for characterization of geological and soil processes, including the nature of soils and regolith (weathered) cover and the alteration footprints of hydrothermal ore deposits. This paper describes work from the Western Australian (WA) Centre of Excellence for 3D Mineral Mapping, which is part of CSIROs Minerals Down Under Flagship and supported by the WA State Government, Geoscience Australia and other Australian Geological Surveys, to generate a series of ASTER mineral group maps (both content and composition) for the whole Australian continent at a 30 m pixel resolution.

Preparation of analysis ready polsar data for the Australian Geoscience Data Cube

This paper describes a CSIRO investigation into the potential use of Sentinel-1 (S1) radar data with the Australian Geosciences Data Cube (AGDC) and in particular the necessity of polarimetric analysis of S1 dual-polarization data within AGDC. As a collaboration between Geoscience Australia, CSIRO and the National Computational Infrastructure, the AGDC provides a new collaborative information technology environment which combines an image database, high performance computing resources, software Application Programming Interfaces (API) to popular analysis tools and libraries, as well as an environment for custom algorithm development. It was created with the view to analysing the increasingly vast quantities of satellite imagery and other Earth observations. With the increasing availability of Earth observation data, especially freely accessed, globally covered and frequently revisited Copernicus Program data, the AGDC provides a potential resource for the analysis and processing of these data, especially where joint analysis with other archives is required. Here we investigate the preparation and necessity of including Sentinal-1 dual-pol SAR data polarimetric processing for the purpose of ingestion into the AGDC.