This Eromanga 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 Eromanga Basin, part of the Great Artesian Basin (GAB) in Australia, is an extensive Mesozoic sedimentary basin filled with a mix of non-marine and marine rocks. The GAB covers about 22% of the Australian land surface, including areas in Queensland, New South Wales, South Australia, and the Northern Territory. The Eromanga Basin is the largest among the basins that form the GAB.
Spanning over 1,250,000 square kilometres in central and eastern Australia, the Eromanga Basin contains rocks ranging from Jurassic to Cretaceous in age. The sedimentary deposits consist of three main basin successions: Early Jurassic to Early Cretaceous fluvial and lacustrine, Early to mid-Cretaceous marine, and Late Cretaceous fluvial-lacustrine successions. The basin's stratigraphic architecture results from a complex interplay between subsidence-controlled accommodation, sediment supply rates, and changing sediment provenance. These controls were influenced by various factors, such as intra-plate stress fields, eustatic sea-level fluctuations, and dynamic mantle-driven topography during the breakup of the Gondwana supercontinent.
During the Jurassic and Early Cretaceous, regional uplift of the Australian continent led to an influx of fluvial sand-rich sediments in the western Eromanga Basin. Subsequent rapid subsidence and global high sea levels during the Early Cretaceous allowed marine sediments to spread across much of Australia, including the Eromanga Basin. The basin later returned to non-marine sedimentation during the Late Cretaceous with deposition of the Winton Formation, followed by closure due to an east-directed Late Cretaceous compressional event.
This rapid deposition of the Late Cretaceous Winton Formation played a crucial role in generating and expelling hydrocarbons from various source intervals. The movement of the Australian continent significantly impacted the basin, causing most tectonic activity to occur on the southern side of a prominent keel near Innamincka in the southern half of the GAB. Additionally, variations in the mechanical properties of the sub-lithospheric mantle affected stress distribution, leading to changes in surface elevation and the expression of discharge from aquifers, potentially influencing the location and pattern of spring sites within the South Australian part of the GAB.
