Darling Basin hydrogeological inventory

This Darling Basin dataset contains descriptive attribute information for the areas bounded by the relevant spatial groundwater feature in the associated Hydrogeology Index map. Descriptive topics are grouped into the following themes: Location and administration; Demographics; Physical geography; Surface water; Geology; Hydrogeology; Groundwater; Groundwater management and use; Environment; Land use and industry types; and Scientific stimulus. The geological Darling Basin, covering approximately 130,000 square kilometres in western New South Wales (with parts in South Australia and Victoria), is filled with over 8,000 m of mainly Devonian sedimentary rocks formed in various environments, from alluvial to marine. It sits atop regional basement structures, coinciding with boundaries between Late Paleozoic Kanmantoo, Lachlan, and Southern Thomson Fold Belts. The basin's outcrops are scarce, obscured by younger rocks and sediments. Sedimentary rocks from Late Silurian to Early Carboniferous periods make up the basin, with marine shales and fluvial quartz-rich sandstones being the most common. The Menindee and Bancannia Troughs rest unconformably over Proterozoic and Lower Paleozoic basement rocks, while eastern sub-basins onlap deformed and metamorphosed Lower Paleozoic rocks. A major tectonic shift at the end of the Ordovician transformed south-eastern Australia's palaeogeography from a marginal marine sea to deep troughs and basins. The Darling Basin's discrete sedimentary troughs formed in areas of maximum tectonic extension, including the Ivanhoe, Blantyre, Pondie Range, Nelyambo, Neckarboo, Bancannia, Menindee troughs, and Poopelloe Lake complex. Spatial variation in sedimentary facies indicates potential interconnections between the troughs. The western basin overlies Proterozoic and Lower Paleozoic rocks of the Paroo and Wonominta basement blocks, while the eastern basin onlaps folded, faulted, and metamorphosed older Paleozoic rocks of the Lachlan Fold Belt. The Darling Basin has seen limited hydrocarbon exploration, with wells mostly situated on poorly-defined structures. Indications of petroleum presence include gas seeping from water bores, potential source rocks in sparsely sampled Early Devonian units, and occasional hydrocarbon shows in wells. Reservoir units boast good porosity and permeability, while Cambrian to Ordovician carbonates and shales beneath the basin are considered potential source rocks.