Sedimentary rocks (Great Artesian Basin)

Sedimentary rocks (Great Artesian Basin)

• Sedimentary basins
• Geology
• Hydrology
• GDEs

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Sedimentary rocks of the Great Artesian Basin (and other adjoining and underlying basins)

The Great Artesian Basin is a hydrogeological basin containing layered formations of Cretaceous, Jurassic and Triassic sedimentary rocks of variable grain size and permeability. The Great Artesian Basin is composed of various geological basins and sub-basins. Sedimentary rocks may store and transmit groundwater through inter-granular pore space, fractures and weathered zones. The geological formations shown in the cross-section of this model will apply to the Queensland Lake Eyre Basin (drainage basin) footprint.

Sedimentary rocks with coarser grain size (for example, the Precipice Sandstone) are generally more permeable than those with finer grain size (such as the Wallumbilla Formation). Groundwater can discharge locally (e.g. springs) at the surface from the sedimentary rock aquifers typically along footslopes, fault or fractures. Younger geological material such as those that comprise the Lake Eyre Basin (drainage basin) may overlie the sedimentary rocks of the Great Artesian Basin and these landscapes are depicted in other conceptual models.

Sedimentary rock aquifers may provide a range of ecosystems with water required to support their fauna and flora communities, ecological processes and delivery of ecosystem services.

• Palustrine (e.g. swamps), lacustrine (e.g. lakes) and riverine (e.g. streams and rivers) wetlands may depend on the surface expression of groundwater from the underlying sedimentary rock aquifers.
• Terrestrial vegetation may depend on the subsurface presence of groundwater, typically using deep roots to access groundwater in the capillary zone above the water table.
• Unconfined sedimentary rock aquifers may support aquifer ecosystems which can be indicated by the presence of stygofauna.

Additional Information

• Queensland's plan to protect our Great Artesian Basin
• The Hydrology of the Great Artesian Basin - YouTube
• Pictorial conceptual model PDF

Last updated: 31 January 2022