The Eucla Basin is an artesian depression located in

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to ...

and

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

. The onshore-offshore depression covers approximately 1,141,000 km² and slopes southward to an open bay known as the

Great Australian Bight The Great Australian Bight is a large oceanic bight, or open bay, off the central and western portions of the southern coastline of mainland Australia. Extent Two definitions of the extent are in use – one used by the International Hydro ...

. It extends more than 500 km offshore and about 350 km inland from the coastline. The Eucla Basin is a

Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configu ...

basin consisting mostly of

carbonate A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonat ...

sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sa ...

s and

sedimentary Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

rocks In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition, and the way in which it is formed. Rocks form the Earth's ...

. The basin contains a

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

aquifer An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials ( gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characteri ...

at its base (confined), and an unconfined

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms wh ...

aquifer. The surface area of the basin (and

Nullarbor Plain The Nullarbor Plain ( ; Latin: feminine of , 'no', and , 'tree') is part of the area of flat, almost treeless, arid or semi-arid country of southern Australia, located on the Great Australian Bight coast with the Great Victoria Desert to i ...

) consists mostly of grazing and rangeland, but

nickel Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow ...

and

gold Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile ...

are mined at the western end. Very few people live in this part of the country, with most of the region having fewer than one inhabitant per km². In normal years, the area receives less than 250 mm of

precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hai ...

. Due to a shortage of regional seals and

source rock In petroleum geology, source rock is rock which has generated hydrocarbons or which could generate hydrocarbons. Source rocks are one of the necessary elements of a working petroleum system. They are organic-rich sediments that may have been deposi ...

s, the basin has poor

petroleum Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crude ...

prospects, but it is forming as a major

zircon Zircon () is a mineral belonging to the group of nesosilicates and is a source of the metal zirconium. Its chemical name is zirconium(IV) silicate, and its corresponding chemical formula is Zr SiO4. An empirical formula showing some of th ...

producing area, and includes the Cyclone Zircon Project.

Physiography

The Eucla Basin is one of the distinct physiographic provinces of the larger West Australian Shield. It includes the smaller Eyre Coastal Plain and Eucla Shelf physiographic sections. The physiographic units within the basin are:Chapter 2 Physiography pp. 16 - 36 of * Bunda Plateau - the plateau * Wylie Scarp,

Baxter Cliffs The Baxter Cliffs is a long stretch of coastal cliff on the south coast of Western Australia. The Baxter Cliffs are up to 80 metres high and extend for almost 200 kilometres along the coast, from Point Culver in the west, which marks the no ...

, Hampton Range, and

Bunda Cliffs The Bunda Cliffs, also known as the Nullarbor Cliffs, are a coastal scarp on the southern coast of Australia, extending from the western coast of South Australia to the south-eastern corner of Western Australia. Geography The Bunda Cliffs e ...

- the scarp * Roe Plains and Israelite Plain - the plains * Eucla Shelf - continental shelf

References

{{Authority control Depressions of Australia Geology of Western Australia Physiographic provinces Sedimentary basins of Australia

Physiography

See also

References