Clarence-Moreton Basin hydrogeological inventory

This Clarence-Moreton 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 formation of the Clarence-Moreton Basin initiated during the Middle Triassic due to tectonic extension. This was followed by a prolonged period of thermal cooling and relaxation throughout the Late Triassic to the Cretaceous. Deposition of a non-marine sedimentary succession occurred during this time, with the Clarence-Moreton Basin now estimated to contain a sedimentary thickness of up to 4000 m. There were three main depositional centres within the basin, and these are known as the Cecil Plain Sub-basin, Laidley Sub-basin and Logan Sub-basin.

The Clarence-Moreton Basin sediments were originally deposited in non-marine environments by predominantly northward flowing rivers in a relatively humid climate. The sedimentary sequences are dominated by a mixed assemblage of sandstone, siltstone, mudstone, conglomerate and coal. Changing environmental conditions due to various tectonic events resulted in deposition of interbedded sequences of fluvial, paludal (swamp) and lacustrine deposits.

Within the Clarence-Moreton Basin, coal has been mined primarily from the Jurassic Walloon Coal Measures, including for the existing mines at Commodore and New Acland. However, coal deposits also occur in other units, such as the Grafton Formation, Orara Formation, Bundamba Group, Ipswich Coal Measures, and Nymboida Coal Measures.

Overlying the Clarence-Moreton Basin in various locations are Paleogene and Neogene volcanic rocks, such as the Main Range Volcanics and Lamington Volcanics. The thickness of these volcanic rocks is typically several hundred metres, although the maximum thickness of the Main Range Volcanics is about 900 m. Quaternary sediments including alluvial, colluvial and coastal deposits also occur in places above the older rocks of the Clarence-Moreton Basin.