Geology of australia

Australia is located on an ancient platform , bounded in the east by the Hercynian folded region - the Tasmanian geosyncline , or the Tasmanian belt of Paleozoic folding. In the western part of the platform, within two large shields (Yilgarn and Pilbara) and several scattered speeches (Goler, Musgrave, Aranta and others). the Archean crystalline foundation is exposed. It includes ancient granite – gneiss and granulite complexes, whose age is estimated at 2700–3400 Ma, as well as less metamorphosed complexes of green-stone belts (age from 3300 to 2600 Ma). The latter are represented by basic and ultrabasic metavolcanites, meta-sedimentary and interbedded rocks - ferruginous quartzites, graywackes, and siliceous rocks. The foundation of the eastern part of the platform is composed of metamorphosed volcanic-sedimentary formations of the Lower Proterozoic (Georgetown and others)., Which are associated with pyrite lead-zinc mineralization (Broken Hill region). Deposits of lithium, tantalum, niobium, beryllium and other rare metals , as well as precious stones , are confined to granite shield complexes and performances of the platform foundation. Of the Precambrian formations, the Upper Archean series of greenstone belts of Western Australia are of the greatest mineralogical value, with gold ore deposits associated with metabasalts and diabases, sulfide nickel deposits, as well as deposits of titanomagnetite vanadium ores, chrysotile and amphibole asbestos . Sedimentary and volcanogenic complexes of the cover lie on the crystalline basement.

In Western Australia, the oldest cover horizons belong to the Lower Proterozoic and are represented by sandstones, interbedded with basalts , a ferruginous-siliceous rock (the largest deposits of iron ore are confined to it - the Hamersley Basin), dolomites and acidic effusives.

In the north of the country, the Lower Proterozoic terrigenous strata of the cover transform into sedimentary formations of the mine geosynclinal troughs Pine Creek (which are associated with uranium stratiform deposits), Tennant Creek, etc., which are overlain by terrigenous formations and acidic volcanic-plutomic complexes. The Upper Proterozoic and Paleozoic horizons of the cover are represented by terrigenous clay-carbonate deposits that fill the syneclises of Carnarvon, Canning, and the Amadies, MacArthur, Georgina, and other troughs. Horizons of phosphorites, gypsum, rock salt, and manganese ore deposits are known in these deposits, as well as stratiform polymetric deposits.

In South Australia, similar strata make up the Adelaide folded system, extended in the meridional direction. The Mesozoic and Cenozoic sequences of the platform cover are predominantly sandy-clay, often coal-bearing sediments; only in the Perth graben in the western part of the continent, besides them, are marine sediments of the Triassic and Cretaceous known.

The eastern part of the Australian platform and the zone of its junction with the Tasmanian belt of Paleozoic folding are overlain by the Meso-Cenozoic cover, which fills the cavity of the inland East Australian basin (the Great Artesian basin ). Most of the Tasmanian belt is occupied by the Laclan fold system. The base complex of the Tasmanian geosyncline is exposed in several isolated blocks and consists of gneisses and quartzites of the Lower Proterozoic (Georgetown region) or Upper Proterozoic-Lower Paleozoic crystalline schists (Brisbane region).

Powerful geosynclinal formations of the Lower and Middle Paleozoic - Cambrian ophiolites, conglomerates, sandstones and filites, carbonate rocks of Ordovician and Silurian , Lower and Middle Devonian thickerrigenous rocks covered with effusives and tuffs are widespread within the Laclan system. Folding at the end of the Middle Devonian was accompanied by powerful manifestations of magmatism. Deposits of tin, tungsten, molybdenum, bismuth, copper, lead and zinc are associated with deposits of the Middle Devonian. Continental red-colored deposits and acidic volcanogenic strata of the Upper Devonian, Carboniferous, and Perm fill individual grabens and orogenic depressions. In the folded system of New England on the rocks of the base complex, thick graywackes of the sequence are found with interlayers of spilites, keratophirs, andesites and lenses of organogenic limestones of the Devonian period. Carbon deposits are represented by sand-siltstones, containing layers of limestone, siliceous shales and conglomerates; Permo-Triassic deposits - by horizons of volcanic rocks of acidic and alkaline compositions (which are associated with gold-copper, tin-tungsten, molybdenum-bismuth vein deposits), as well as marine and continental coal-bearing sandy-clay strata that fill grabens and troughs (the largest Bouensky and Sydney).

The folded region of eastern Australia and Tasmania during the Cenozoic period was captured by the processes of volcanism, resulting in the formation of a series of basalt plateaus that form a belt from Queensland to Tasmania . In the volcanic strata, in addition to basalts, alkaline rocks are present. In the post-trade period, the continent experienced intensive development of the weathering crust , often of the lateritic type - deposits of bauxite, nickel silicate and uranium ores are associated with it. The formation of coastal-sea beaches, in the deposits of which developed deposits of heavy sand, enriched with zircon, monazite, ilmenite, rutile.

• Hydrogeology of Australia
• Australia Minerals
• The history of the development of mineral resources in Australia
• Mining Australia
• Australian economy
• Geology of Victoria

• Mountain Encyclopedic Dictionary, vol. 3. / Ed. V.S. Beletsky. - Donetsk: Eastern Publishing House, 2004. - 752 p. ISBN 966-7804-78-X