With high signal-to-noise, groundwater chemistry is a useful medium for geological sensing and mineral exploration in specific environments. Additionally, they are sensitive to faults and other geological structures. Hydrogeochemistry may also add value to mineral exploration where prospective rocks are covered within basin margins.
Uptake of this technology is being encouraged through the development of a robust and cost-effective methodology with field guides, notebooks, and field apps. Site studies have tested hydrogeochemical responses to mineralisation, and sensitivity and normalisation of sampling methods.
CSIRO has obtained publicly available groundwater databases, and processed them using robust QA/QC measures to develop ‘seamless’ data across Australia. Datasets include anything from single salinity measurements up to 60+ elements per sample. This data has now been combined with datasets from Geoscience Australia and launched on the Bureau of Meteorology Explorer portal.
At the Terrane scale, specific indices can delineate large scale lithologies and major mineral camps. Other large systems, such as IOCG’s or Cu Porphyries may also be observable. At the Prospect scale, indicator elements (e.g., Au, Ni, Cu, Zn, W, As) are commonly valuable, with commodity indices developed for smaller targets such as Ni or VHMS.
In many areas across inland Australia, groundwater is commonly used by humans and livestock for consumption. Mapping of health sensitive solutes such as nitrate can inform water usage and treatment requirements.
Thus, hydrogeochemistry can positively assist exploration at varying scales, and now it has been combined and is publicly available, provide baseline chemical data for human and agricultural health.