Hydrogeochemical Mapping of the Australian Continent

[摘要] This Report is prepared as a foundation document for the hydrogeochemical database of Australia. The use of groundwater chemistry has extensive value in mineral exploration, water resources management, environmental monitoring, agriculture and many other industries. Over the past decades CSIRO has sampled and analysed thousands of groundwaters in many regions of Australia. In addition, other agencies, industry and various individuals have gathered similar samples and results. In a major effort, CSIRO has compiled their data with others and performed extensive quality control to ensure the results are comparable and useable for future public benefit.This report outlines the sources and results of this data and demonstrates how to access the resource of a continental scale hydrogeochemistry data base. Chapter 1 is an introduction, Chapter 2 reports the data sources broken down by state and with links to source data and publications or references. Chapter 3 demonstrates the current process to extract the data from CSIRO’s Data Access Portal (DAP) that is available to all. Chapter 4 explains the key considerations and management of quality control of the data, especially with data that was sampled or analysed in slightly different or unspecified ways. This is probably the most important aspect of the report as it demonstrates the process of making these many data sources interoperable as one and also, importantly, where the data is not comparable and how it has been filtered or censored for use. The data modelling in Chapter 5 is principally concerned with pH-Eh and other variants of activity-activity diagrams to support modelling of solute chemistry, and in turn, geochemical distribution. Similarly, individual modelling of every sample and calculation of mineral solubilities is an additional mapping and analysis tool. These calculations may vary depending on thermodynamic data bases used, however, the trends observed are robust for future application. Additional ratios and indices created from CSIRO are also added to this section.Chapters 6, 7 8 and 9 report the chemistry results. These are mostly presented as maps on a continental-scale. However, it is important to note that in many cases this data can be used at much closer scale, with many samples collected around key sites of interest (for examples mine sites) and these may be spaced 10s of metres apart in some cases. The results in this report focus mostly on the mineral exploration potential of this data-rich collection of groundwater results. Chapter 7 discusses major groundwater processes, Chapter 8 covers major elements and associated minerals progressing through to trace inorganic analytes measured. Chapter 9 presents the isotope results for O, H, S and Sr where there were enough samples to warrant discussion. Some groundwater samples have been subject to less common analyses (e.g. Pb, N, Zn isotopes) but these are not reported as it was niche, specific site results.Results show that there are clear patterns in the groundwater that can be observed at the continental scale. Parameters like pH, salinity and nitrate clearly demonstrates this, whereas trace metals like Au are excellent predictors of gold-rich mineral resource areas. General results are presented at the country scale and comments pertaining to mineral exploration potential are added primarily due to the focus of CSIRO Mineral Resources’ expertise and research focus. References throughout the text provide much more detailed specific information. Water quality for drinking water or stock requirements are also commonly referenced in the text where relevant.

[发布机构] CSIRO

[学科分类] 地球科学(综合)