Arafura Basin hydrogeological inventory

This Arafura 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 Arafura Basin is a large intracratonic sedimentary basin along the northern continental margin of Australia. Over 90% of the basin occurs offshore in relatively shallow marine waters of the Arafura Sea, with the basin extending northwards beyond Australia's territorial claim. The southern part of the basin is onshore in northern Arnhem Land. Older Paleo- to Mesoproterozoic rocks of the northern Macarthur Basin underlie most of the onshore basin, whereas Mesozoic and Cenozoic sediments of the Money Shoal Basin unconformably overlie the offshore basin. The sedimentary record of the Arafura Basin spans greater than 250 million years, from the late Neoproterozoic to the early Permian. However, subsidence was episodic and restricted to four main phases of regional subsidence interspersed with relatively long periods of tectonic quiescence. Consequently, the entire sedimentary succession of the basin is relatively structurally conformable. The oldest rocks are the Neoproterozoic to Cambrian Wessel Group. These are overlain by the Middle Cambrian to early Ordovician Goulburn Group, followed by the Late Devonian Arafura Group. The uppermost sequence is Late Carboniferous to early Permian (an equivalent of the Kulshill Group from the neighbouring Bonaparte Basin). The sedimentary rocks of the Arafura Basin are clastic-dominated and include sandstone, shale, limestone, dolostone and minor coal and glacial deposits. Most of the Arafura Basin formed within shallow marine environments, with evidence for fluvial conditions largely restricted to the Carboniferous to Permian rocks. There are no detailed basin-scale studies on the hydrogeology and groundwater systems of the Arafura Basin. Previous hydrogeological investigations by the Northern Territory Government during the 1980s and 1990s focused on groundwater supplies for remote communities such as Maningrida, Galiwinku and Millingimbi. Groundwater for these communities is sourced from fractured rock sandstone aquifers, most likely units of the Arafura Basin such as the Marchinbar Sandstone and Elcho Island Formation of the Wessel Group. The aquifers are fractured and extensively weathered up to 100 metres below surface.