|alluviated||Alluvium: An unconsolidated accumulation of stream-deposited sediments, including sands, silts, clays or gravels.|
|aquifer||A subsurface rock or sediment unit that is porous and permeable. To be an aquifer it must have these traits to a high enough degree that it stores and transmits useful quantities of water.|
|gawler craton||The Gawler Craton covers approximately 440,000 square kilometres of central South Australia. Its Precambrian crystalline basement crustal block was cratonised ca. 1550-1450 Ma. Prior to 1550 Ma the craton comprised a number of active Proterozoic orogenic belts extending back in time to at least 2450 Ma.
The Craton can be subdivided into a number of tectonic subdomains on the basis of structure and tectonostratigraphic history The south-central Eyre Peninsula straddles the boundary between the Archaean to early Palaeoproterozoic Coulta Subdomain and the Cleve Subdomain, a Palaeoproterozoic orogenic belt ("mobile zone") probably representing a shelf or basinal depository for the Hutchison Group (ca. 1900-1845 Ma) prior to its deformation during the Kimban Orogeny (ca. 1845-1710 Ma). On northeastern Eyre Peninsula, the Cleve Subdomain is bounded by the slightly younger Moonta Subdomain which is characterised by less intensely deformed metamorphosed acid volcanics and sediments ranging from the Myola Volcanics and Moonta Porphyry to the Moonabie Formation and Wandearah Metasiltstone.
Subsequent deformation on the craton has been largely epeirogenic forming shallow fault-bounded intracontinental depressions represented by Cainozoic basins, the southern continental margin and Spencer Gulf.
|artisian basin||An aquifer that is bounded above and below by impermeable rock or sediment layers. The water in the aquifer is also under enough pressure that, when the aquifer is tapped by a well, the water rises up the well bore to a level that is above the top of the aquifer. The water may or may not flow onto the land surface.|
|leaching||The removal of soluble constituents from a rock or soil by moving ground water or hydrothermal fluids.|
|Phanerozoic||The Phanerozoic Eon is the current eon in the geologic timescale, and the one during which abundant animal life has existed. It covers roughly 545 million years and goes back to the time when diverse hard-shelled animals first appeared.|
|Precambrian||The Precambrian (Pre-Cambrian) is an informal name for the supereon comprising the eons of the geologic timescale that came before the current Phanerozoic eon. It spans from the formation of Earth around 4500 Ma (million years ago) to the evolution of abundant macroscopic hard-shelled animals, which marked the beginning of the Cambrian, the first period of the first era of the Phanerozoic eon, some 542 Ma. It is named after the Roman name for Cymru/Wales - Cambria - where rocks from this age were first studied.|
|subterranean||below ground, under the earth, underground|
|unconfined aquifer||An aquifer that is not overlain by an impermeable rock unit. The water in this aquifer is under atmospheric pressure and is recharged by precipitation that falls on the land surface directly above the aquifer.|