The Great Victoria Desert is Australia's largest desert: a belt of red sand ridges, spinifex plains, gibber (stony) flats and salt lakes covering about 348,750 km² (134,650 sq mi) across Western Australia and South Australia. It runs more than 700 km from the Eastern Goldfields near Kalgoorlie to the Gawler Ranges in South Australia, with the Gibson Desert to the north and the treeless Nullarbor Plain separating it from the Southern Ocean. Rainfall is only 200 to 250 mm a year, arriving irregularly and often in thunderstorms, of which the desert averages 15 to 20 a year. Ernest Giles, the first European to cross it, named it after Queen Victoria in 1875. Its surface is young, but it rests on some of the oldest crust on Earth, and the story of how it formed runs from Archaean granite to sand dunes shaped by Pleistocene winds.
Archaean and Proterozoic Basement: Yilgarn, Musgrave and Gawler Blocks
Three ancient crustal blocks frame the desert. On its western edge lies the Yilgarn Craton, which makes up much of the Western Australian landmass. It was assembled between about 2.94 and 2.63 billion years ago, when older fragments of continental crust were welded together; granite and granodiorite now make up more than 70% of the craton, and the same accretion delivered most of its gold. The goldfields around Kalgoorlie and Laverton, where the desert's western tracks begin, sit on this Archaean rock.
To the north-east runs the Musgrave Block, an east-west belt of granulite and gneiss about 500 km long that crosses from South Australia into Western Australia. Its oldest high-grade rocks date from about 1,550 to 1,300 million years ago, and the mafic-ultramafic Giles Complex intruded around 1,080 million years ago. In the south-east the Gawler Craton, which covers about 440,000 km² of South Australia, became a stable block between roughly 1,550 and 1,450 million years ago. Just before that, around 1,595 to 1,592 million years ago, the Gawler Range Volcanics poured out roughly 30,000 km³ of rhyolite and dacite lava, one of the largest felsic eruptions preserved anywhere. Their eroded stumps are the Gawler Ranges that mark the desert's eastern limit. Between these blocks, buried under younger rock, lies the Proterozoic link that once joined the Yilgarn and Gawler cratons.
The Officer Basin: Six Kilometres of Neoproterozoic Sediment
Along the state border, the desert country overlies the Officer Basin, a sedimentary basin of about 320,000 km² straddling the border between South Australia and Western Australia. For roughly 350 million years during the Neoproterozoic it collected sediment, and in places the pile is more than 6 km thick, deepest along the northern edge and thinning southwards. Its lowest major unit, the Browne Formation of about 800 million years ago, is shale, dolomite and thick evaporite laid down in tidal flats and lagoons. Later compression squeezed that salt upwards into diapirs that buckle the overlying strata. The Kanpa Formation above it carries stromatolites, a sign of shallow, warm carbonate seas, and zircon grains in its top sandstone give a maximum age of 725 million years.
Around 630 to 520 million years ago the Petermann Orogeny forced the Musgrave Block upwards by 30 to 40 km along the Woodroffe Thrust and other faults. Debris stripped from the rising mountains spread into the surrounding basins, and the same pulse of sediment built the arkose of Uluru and the conglomerate of Kata Tjuta to the north. The Officer Basin probably behaved as a foreland basin during this event, and deposition ended around 490 million years ago with the Delamerian Orogeny. Lava flows and the younger Gunbarrel Basin were later laid over it. Fewer than 20 exploration wells had been drilled into the basin by 2020, which is one measure of how remote this country still is.
Rifting from Antarctica and the Eucla Basin to the South
For hundreds of millions of years the Great Victoria country lay deep inside Gondwana, joined to Antarctica along what is now the southern coast. Rifting between the two continents began in the Jurassic, a mid-ocean ridge developed offshore through the Cretaceous, and separation is dated to around 84 million years ago, though the final break-up is placed in the Eocene. South of the desert lies the Eucla Basin, a Cenozoic depression of about 1,141,000 km² onshore and offshore, made mostly of carbonate sediments, that slopes south to the Great Australian Bight.
The Nullarbor Plain on its surface is a former shallow seabed: its limestone is built from the skeletons of bryozoans, foraminifera, echinoids and red algae, laid down in formations from the mid-Eocene to the Miocene. The plain is the world's largest single exposure of limestone bedrock at about 200,000 km², and it lies directly south of the Great Victoria Desert, separating the sand country from the Southern Ocean.
Serpentine Lakes and the Dead Rivers of the Palaeo-Drainage
Water once flowed across this plateau in large river systems that have since stopped running. Their former valleys, called palaeochannels, survive as chains of salt lakes. The clearest example is the Serpentine Lakes, which wind for almost 100 km along the South Australia–Western Australia border, mostly inside Mamungari Conservation Park. When full they cover about 97 km², but normally their beds are dry clay, silt and quartz sand under a salt crust, at about 264 m above sea level. They form the main channel of a now-inactive palaeo-drainage system dating from the Palaeozoic; its other channels are buried under sand dunes and hard to trace. Magnesium-rich tektites, glassy debris from ancient meteorite impacts, have been found on their beds.
Salt lakes of the same kind dot the rest of the region, such as those protected in the Yeo Lake and Plumridge Lakes nature reserves in Western Australia, and Lake Gairdner beyond the desert's eastern fringe. Lake Gairdner is more than 160 km long, its salt more than 1.2 m thick in places, and in flood it is counted as Australia's third-largest salt lake. Because the land is so flat and the climate so dry, rain that does fall drains into these closed basins and evaporates, concentrating salt rather than flushing it to the sea. Across Australia's deserts this pattern of playa lakes, salt lakes and short-lived streams is the normal state of drainage.
Pleistocene Wind and the Dune Ridges of the Great Victoria
The youngest layer of the landscape is the sand. On the Musgrave Block, wide calcrete plains are covered by Pleistocene wind-blown dunes, and further south thin Tertiary sands and recent dunes overlie the Fowler Domain on the north-western flank of the Gawler Craton. The pattern repeats across the desert: many small sandhills and sand ridges with wooded flats between them, grassland plains, salt lakes and patches of gibber, a closely packed pebble surface. In the north-east of Queen Victoria Spring Nature Reserve, for example, sand plains and dunes alternate with occasional salt pans on red-brown soils.
Climate keeps the dunes in place today. Summer days reach 32 to 40 °C and winter days fall to 18 to 23 °C, and the rainfall, though higher than in many of the world's deserts, is lost quickly to heat and evaporation. Sand dunes predominate along most of the Anne Beadell Highway, where summer temperatures can approach 50 °C.
What the Rocks and Sand Built: Spinifex, Mulga and Marsupial Moles
Poor, sandy soils on stable ground produced a distinctive desert woodland. In the swales between the ridges grow the eucalypts Eucalyptus gongylocarpa and Eucalyptus youngiana and mulga (Acacia aneura) shrubs, scattered over hummocks of spinifex, especially Triodia basedowii. Large animals are few, mainly emus, red kangaroos and dingoes, since the desert lies north of the Dingo Fence. Reptiles do far better, among them the vulnerable great desert skink, the perentie and sand goanna, and the Central Ranges taipan, discovered in 2007.
The deep sand is a refuge in its own right. The southern marsupial mole spends its life burrowing through it, and the water-holding frog waits out droughts underground. Small marsupials include the endangered sandhill dunnart and the crest-tailed mulgara, and the malleefowl nests in Mamungari Conservation Park. Because farming never took hold here, much of the habitat is intact, and about 31% of the desert lies in protected areas, from the Great Victoria Desert Nature Reserve in Western Australia to Yellabinna and Tallaringa in South Australia.
Mamungari, Maralinga and the Tracks of Len Beadell
Aboriginal people lived in this country long before Europeans arrived, and most residents today are Aboriginal Australians, including Kogara, Mirning and Pitjantjatjara people. Water dictated every journey. When Giles reached Queen Victoria Spring in September 1875 on the first successful east-west crossing to the Western Australian coast, he found it full after 17 days without water; the Elder Scientific Exploring Expedition arrived in 1891 and found it dry. The spring now lies in a nature reserve of about 212,600 ha gazetted in 1970.
The desert's remoteness drew the British nuclear programme. It began with two tests at Emu Field, 480 km north-west of Woomera: Totem 1 on 15 October 1953, which William Penney estimated at about 10 kilotons, and Totem 2 on 27 October, later measured at 8 kilotons. Testing moved south to Maralinga, where Operation Buffalo began on 27 September 1956 and Operation Antler followed in 1957, leaving areas contaminated with plutonium-239. Spinifex people were removed from their homelands before the tests, and the community of Tjuntjuntjara, 560 km north-east of Kalgoorlie, was founded in 1988 after a water bore was drilled.
Surveyor Len Beadell cut the tracks that still cross the dunes. The Anne Beadell Highway runs 1,325 km from Coober Pedy to Laverton and was built in stages between 1953 and 1962; the Connie Sue Highway, about 650 km from Warburton to Rawlinna, was finished in 1962 and named after his infant daughter. In May 2004, South Australia handed back title to 21,000 km² of land, including the Serpentine Lakes and the conservation park, to the Maralinga Tjarutja and Pila Nguru people. The park, a UNESCO biosphere reserve since 1977, was renamed Mamungari on 30 November 2006 and is jointly managed by its traditional owners. To follow the limestone country that borders the desert to the south, read our guide to the Nullarbor Plain, or place both within the continent's wider landforms in our overview of Australia's geography.