HYDROLOGICAL PROCESSES IN THE TYRRELL BASIN, SOUTHEASTERN AUSTRALIA

The Tyrrell Basin in semi-arid southeastern Australia provides an ideal setting where saline-acid groundwaters, evaporites, redbeds, syngenetic sulphides and thick groundwater brine bodies are all present and, in many instances, are actively forming today. The relatively flat landscape and the associated regional groundwater systems with their concomitantly low hydraulic gradients create a setting in which is developed a clearer than normal aerial separation of a wide range of complex interwoven physico-chemical processes. Detailed work in the Tyrrell Basin over a number of years has enabled the establishment of a hydrogeological framework which forms the basis for unravelling otherwise complicated hydrochemical interactions between groundwater systems and salt lakes. Indeed, the interactions between groundwater flow systems and the regional groundwater discharge landscape in general, and the spring zones of salt lakes in particular, have important implications, bearing upon the solution, migration, deposition and concentration of salts and metals by regional groundwater systems in arid and semi-arid areas.