Yilgarn Craton
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The Yilgarn Craton is a large
craton A craton (, , or ; from grc-gre, κράτος "strength") is an old and stable part of the continental lithosphere, which consists of Earth's two topmost layers, the crust and the uppermost mantle. Having often survived cycles of merging an ...
that constitutes the bulk of the
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 th ...
n land mass. It is bounded by a mixture of
sedimentary basins Sedimentary basins are region-scale depressions of the Earth's crust where subsidence has occurred and a thick sequence of sediments have accumulated to form a large three-dimensional body of sedimentary rock. They form when long-term subsiden ...
and Proterozoic
fold and thrust belt A fold and thrust belt (FTB) is a series of mountainous foothills adjacent to an orogenic belt, which forms due to contractional tectonics. Fold and thrust belts commonly form in the forelands adjacent to major orogens as deformation propagates o ...
s.
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 t ...
grains in the
Jack Hills The Jack Hills are a range of hills in Mid West Western Australia. They are best known as the source of the oldest material of terrestrial origin found to date: Hadean zircons that formed around 4.39 billion years ago. These zircons have enabl ...
, Narryer Terrane have been dated at ~4.27 Ga, with one
detrital Detritus (; adj. ''detrital'' ) is particles of rock derived from pre-existing rock through weathering and erosion.Essentials of Geology, 3rd Ed, Stephen Marshak, p G-7 A fragment of detritus is called a clast.Essentials of Geology, 3rd Ed, Stephe ...
zircon dated as old as 4.4 Ga. The Murchison Province of the craton contains the oldest dated
meteorite A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or Natural satellite, moon. When the ...
impact crater An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact crater ...
, at 2229 ± 5 Ma.


Geology

The Yilgarn Craton appears to have been assembled between ~2.94 and 2.63 Ga by the accretion of a multitude of formerly present blocks or
terrane In geology, a terrane (; in full, a tectonostratigraphic terrane) is a crust (geology), crust fragment formed on a tectonic plate (or broken off from it) and Accretion (geology), accreted or "Suture (geology), sutured" to crust lying on another pla ...
s of existing
continental crust Continental crust is the layer of igneous, sedimentary, and metamorphic rocks that forms the geological continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called '' sial'' be ...
, most of which formed between 3.2 Ga and 2.8 Ga. This accretion event is recorded by widespread
granite Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies under ...
and
granodiorite Granodiorite () is a coarse-grained ( phaneritic) intrusive igneous rock similar to granite, but containing more plagioclase feldspar than orthoclase feldspar. The term banatite is sometimes used informally for various rocks ranging from gr ...
intrusions, which comprise over 70% of the Yilgarn craton; voluminous
tholeiitic The tholeiitic magma series is one of two main magma series in subalkaline igneous rocks, the other being the calc-alkaline series. A magma series is a chemically distinct range of magma compositions that describes the evolution of a mafic magma ...
basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...
and komatiite
volcanism Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the surface called ...
; regional
metamorphism Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of ch ...
and deformation as well as the emplacement of the vast majority of the craton's endowment in
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 met ...
mineralisation. These accretion events occurred in several phases, probably by accretion of continental fragments separated by pauses in
subduction Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...
, with renewed activity occurring episodically. The craton is primarily composed of approximately 2.8 billion year old (~2.8 Ga) granite-gneiss metamorphic terrain (the Southwestern Province and Western Gneiss Belt), and three granite- greenstone terrains (the North-East Goldfields, the Southern Cross and the greenschist
metamorphic Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causi ...
Murchison Provinces). Some greenstone belts and granites are as old as 3.1-2.9 Ga, and some are younger, at ~2.75-2.65 Ga. The craton is one of the distinct physiographic provinces of the West Australian Shield physiographic division, which comprises the Stirling-Mount Barren Block, Darling Hills, and Recherche Shelf sections.


Western Gneiss Terrane

The Western Gneiss Terrane is a series of polydeformed high-grade early Archaean metamorphic belts, composed predominantly of
feldspathic Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldsp ...
leucocratic
granulite Granulites are a class of high-grade metamorphic rocks of the granulite facies that have experienced high-temperature and moderate-pressure metamorphism. They are medium to coarse–grained and mainly composed of feldspars sometimes associated ...
gneisses, which represent some of the oldest crustal fragments on Earth. The Western Gneiss Terrane is distinct from the remainder of the Yilgarn Craton in that the latter has a predominance of metavolcanic rocks, both felsic and
mafic A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks incl ...
, whereas the former consists of high-grade metasediments and
gneiss Gneiss ( ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. Gneiss forms at higher temperatures a ...
es of unknown
protolith A protolith () is the original, unmetamorphosed rock from which a given metamorphic rock is formed. For example, the protolith of a slate is a shale or mudstone. Metamorphic rocks can be derived from any other kind of non-metamorphic rock and ...
. The Western Gneiss Terrane is exposed along the western half of the northern margin of the Yilgarn Craton as the
Narryer Gneiss Terrane The Narryer Gneiss Terrane is a geological complex in Western Australia that is composed of a tectonically interleaved and polydeformed mixture of granite, mafic intrusions and metasedimentary rocks in excess of 3.3 billion years old, with the ...
, a composite of heavily polydeformed feldspathic metagranite and metasedimentary amphibolite-grade gneisses and
migmatite Migmatite is a composite rock found in medium and high-grade metamorphic environments, commonly within Precambrian cratonic blocks. It consists of two or more constituents often layered repetitively: one layer is an older metamorphic rock th ...
s, dated at greater than 3.3 Ga and up to 3.8 Ga in age, flanked by the Murgoo Gneiss Terrane (2.95 Ga), as well as sheets of 2.75 Ga to 2.6 Ga granite, obducted
ophiolite An ophiolite is a section of Earth's oceanic crust and the underlying upper mantle that has been uplifted and exposed above sea level and often emplaced onto continental crustal rocks. The Greek word ὄφις, ''ophis'' (''snake'') is found ...
sheets (the Trillbar Complex) and some 2.4 Ga to 2.0 Ga Proterozoic gneiss belts. On the western edge of the Yilgarn Craton, partially covered by Phanerozoic sedimentary basins and in faulted contact with the 2.7 Ga to 2.55 Ga Yilgarn tectonic domains, lies the Jumperding Gneiss Complex of 2.75 to 2.65 Ga age, composed primarily of micaceous
quartzite Quartzite is a hard, non- foliated metamorphic rock which was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tec ...
, quartz-feldspar-biotite-garnet gneiss,
andalusite Andalusite is an aluminium nesosilicate mineral with the chemical formula Al2SiO5. This mineral was called andalousite by Delamétehrie, who thought it came from Andalusia, Spain. It soon became clear that it was a locality error, and that the spe ...
and
sillimanite Sillimanite is an aluminosilicate mineral with the chemical formula Al2SiO5. Sillimanite is named after the American chemist Benjamin Silliman (1779–1864). It was first described in 1824 for an occurrence in Chester, Connecticut. Occurrence ...
schist Schist ( ) is a medium-grained metamorphic rock showing pronounced schistosity. This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes ...
s,
banded iron formation Banded iron formations (also known as banded ironstone formations or BIFs) are distinctive units of sedimentary rock consisting of alternating layers of iron oxides and iron-poor chert. They can be up to several hundred meters in thickness ...
and other exotics, intruded by minor masses of porphyritic granite. Detrital zircons in the Jumperding Gneiss Complex range in age from 3267 ± 30 Ma to 3341 ± 100 Ma, with metamorphic overgrowth dated at 3180 Ma. On the southwest of the Yilgarn Craton the Balingup Gneiss Complex is situated inboard from the Early Proterozoic Leeuwin Complex of metamorphic rocks. The Balingup Complex consists primarily of metasedimentary paragneiss, granite orthogneiss, with minor layers of calc-silicate, ultramafic and ortho-amphibolite gneiss. The metamorphic grade is considered to be peak granulite facies, but the majority has preserved peak amphibolite facies assemblages. In total, the Western Gneiss Terrane sub-blocks represent an earlier substrate upon which the majority of the Yilgarn Craton's about 2.70 to 2.55 Ga greenstone metavolcanic belts have been deposited and into which the voluminous Archaean trondhjemite-tonalite-granodiorite suite and
trondhjemite Trondhjemite is a leucocratic (light-colored) intrusive igneous rock. It is a variety of tonalite in which the plagioclase is mostly in the form of oligoclase. Trondhjemites that occur in the oceanic crust or in ophiolites are usually called pla ...
-
tonalite Tonalite is an igneous, plutonic ( intrusive) rock, of felsic composition, with phaneritic (coarse-grained) texture. Feldspar is present as plagioclase (typically oligoclase or andesine) with alkali feldspar making up less than 10% of the total ...
-
diorite Diorite ( ) is an intrusive igneous rock formed by the slow cooling underground of magma (molten rock) that has a moderate content of silica and a relatively low content of alkali metals. It is intermediate in composition between low-sili ...
suite granites were emplaced.


Murchison Province

The Murchison Province is exposed in the western and northern third of the Yilgarn Craton. The Province is bounded by major transcrustal structures which separate it from the surrounding tectonic provinces of the craton and the Western Gneiss Belt. The Murchison Province Stratigraphy, after Watkins (1990), is divided into six basic structural-stratigraphic components - two greenstone belt metavolcanic-metasedimentary sequences and four suites of granitoids. * Luke Creek Group metavolcanics * Mount Farmer Group * Early granodiorite-monzogranite intrusive suite (now pegmatite-banded orthogneiss) * Monzogranite Suite (now folded, metagranite) * Two post-tectonic differentiated suites of granitoid rocks The structural framework in the northeastern Yilgarn craton was largely shaped by transpression that led to the development of folds, reverse faults, sinistral strike-slip movement on NNW-trending regional shear zones, followed by regional folding and shortening. The later occurred in overlapping tectonic processes. The first deformation event is poorly understood but appears to have involved N-S thrusting. The Murchison Province contains the Yarrabubba crater, which is the oldest dated
meteorite A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or Natural satellite, moon. When the ...
impact crater An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact crater ...
, at 2229 ± 5 Ma. The crater is heavily eroded and nothing remains of the original structure. There is an elliptical aero-magnetic anomaly, measuring approximately 20km by 11km. This impact may have ended the
Huronian glaciation The Huronian glaciation (or Makganyene glaciation) was a period where several ice ages occurred during the deposition of the Huronian Supergroup, rather than a single continuous event as it is commonly misrepresented to be. The deposition of th ...
period of the Snowball Earth geologic era.


Southern Cross Province

The Southern Cross Province lies in the central area of the Yilgarn craton. The Marda–Diemals greenstone belt in the Southern Cross Terrane can be divided into three layers: the lower greenstone belt (ca. 3.0 Ga) characterized by mafic volcanic rock and banded iron formation, a felsic-intermediate volcanism layer, and an upper sedimentary layer (ca. 2.73 Ga) of calc-alkaline volcanic (Marda Complex) and clastic sedimentary rocks ( Diemals Formation). East–West orogeny (ca. 2730–2680 Ma) occurred in two stages; an earlier folding phase and a late phase that resulted in deposition and deformation of the Diemals Formation. Subsequent orogeny (ca. 2680–2655 Ma) resulted in shear zones and arcuate structures. The lithostratigraphy of the Marda–Diemals greenstone belt are similar to the northern Murchison Terrane, but has older greenstones and deformation events than the southern Eastern Goldfields Terrane. This indicates that the Eastern Goldfields Terrane may have accreted to an older Murchison–Southern Cross granite–greenstone nucleus.


Eastern Goldfield Province

The Archaean Norseman-Wiluna Greenstone Belt in the Eastern Goldfield Province contains most of Australia's lode gold deposits, including the famous Kalgoorlie Golden Mile containing the Super Pit. These gold deposits are generally of large tonnage and are confined to the volcanic-intrusive-sedimentary sequences of the greenstone belts and not the granites. There is a pattern of gold distribution along the Archean Boulder-Lefroy shear zone. Extrusive komatiites (ultramafic volcanic rocks) occur along the Norseman-Wiluna Greenstone Belt. A change from volcanic-dominated to plutonic-dominated magmatism occurred in the Norseman-Wiluna Greenstone Belt approximately 2685–2675 Ma. Voluminous high-Ca granite intrusions occurred 2670–2655 Ma. Much of the gold was deposited between 2650–2630 Ma, with much of this associated with strike-slip reactivation of earlier faults (normal and reverse). An earlier gold event 2660-2655 Ma was associated with major extension (normal faulting and granite doming) resulting in the formation of late basins and the intrusion of mantle-derived magmas (syenites and Mafic-type granites/porphyries) and tight anticlockwise PTt paths.


Bounding terranes

The Yilgarn Craton is bound on all sides by younger terranes of various ages, but predominantly of Proterozoic age. The boundaries between the various flanking terranes provide considerable evidence of the post-Archaean events which have involved the Yilgarn Craton.


Perth Basin

The Yilgarn Craton is bound on the western side by the
Perth Basin The Perth Basin is a thick, elongated sedimentary basin in Western Australia. It lies beneath the Swan Coastal Plain west of the Darling Scarp, representing the western limit of the much older Yilgarn Craton, and extends further west offshore. C ...
, of
Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...
age, and is separated from this basin by the Darling Fault. The Perth Basin is considered to be a rift fill basin formed on a passive margin.


Gascoyne Complex

The Perth Basin is bound on the north by the Gascoyne Complex, Glengarry Basin and Yerrida Basin, which are all part of a middle Proterozoic mobile belt which leads east to the
Musgrave Block The Musgrave Block (also known as the Musgrave Province) is an east-west trending belt of Proterozoic granulite-gneiss basement rocks approximately long. The Musgrave Block extends from western South Australia into Western Australia. The Musgra ...
. The Gascoyne complex and other metamorphic belts of this age including reactivation of the Yarlarweelor Gneiss and
Narryer Gneiss Terrane The Narryer Gneiss Terrane is a geological complex in Western Australia that is composed of a tectonically interleaved and polydeformed mixture of granite, mafic intrusions and metasedimentary rocks in excess of 3.3 billion years old, with the ...
, indicate prolonged multi-phased strike-slip movement (relative to the Yilgarn Craton margin) from the late Archaean through to neoproterozoic and even into the Palaeozoic.


Albany-Fraser Orogen

The Yilgarn Craton is bounded on the east-southeast by the ~1,300 Ma Albany-Fraser Orogen, composed primarily of amphibolite to greenschist facies sedimentary
protolith A protolith () is the original, unmetamorphosed rock from which a given metamorphic rock is formed. For example, the protolith of a slate is a shale or mudstone. Metamorphic rocks can be derived from any other kind of non-metamorphic rock and ...
gneisses, migmatites and granites. The Albany-Fraser Orogen displays both subduction-related and prolonged strike-slip tectonic structures and is intimately interconnected with the other Proterozoic basins and mobile belts of Australia.


Sedimentary basin cover

The Yilgarn Craton is partially covered by onlapping sedimentary basins of Palaeozoic and Phanerozoic age in the east and north-east, including the Canning Basin. It is bounded on the western edge by the
Darling Scarp The Darling Scarp, also referred to as the Darling Range or Darling Ranges, is a low escarpment running north–south to the east of the Swan Coastal Plain and Perth, Western Australia. The escarpment extends generally north of Bindoon, to t ...
and Darling Fault which separate the Yilgarn Craton from the Perth Basin to the west, and is covered by several remnant sedimentary basins of Jurassic age such as the Collie Sub-Basin. The Yilgarn Craton also has a considerable Tertiary and younger sedimentary veneer of
palaeochannel A palaeochannel, also spelt paleochannel and also known as palaeovalley or palaeoriver, is a geological term describing a remnant of an inactive river or stream channel that has been filled or buried by younger sediment. The sediments that the ...
deposits derived from prolonged erosion, sedimentation and redeposition of older cover sequences and regolith as well as the Archaean basement itself. Recognised Tertiary cover sequences include the Bremer Basin,
Officer Basin The Officer Basin is an intracratonic sedimentary basin that covers roughly 320,000 km2 along the border between southern and western Australia. Exploration for hydrocarbons in this basin has been sparse, but the geology has been examined f ...
and others.


Regolith

The Yilgarn craton is believed to have remained at or above sea level for a considerable length of time. Some of the Yilgarn
regolith Regolith () is a blanket of unconsolidated, loose, heterogeneous superficial deposits covering solid rock. It includes dust, broken rocks, and other related materials and is present on Earth, the Moon, Mars, some asteroids, and other terrestr ...
is the oldest in the world, recording
weathering Weathering is the deterioration of rocks, soils and minerals as well as wood and artificial materials through contact with water, atmospheric gases, and biological organisms. Weathering occurs ''in situ'' (on site, with little or no movement), ...
events as early as the
Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
Period. This has been created by the generally subtropical latitudes and conditions of the Yilgarn craton, with minimal to no glaciation and generally flat topographical relief resulting in comparatively minor erosion. The regolith is extremely deeply weathered, in some areas completely converted to saprolite up to 100 metres below surface. This is considered to have been produced during Caenozoic to Palaeocene tropical conditions, as evidenced by mottled duricrust which records fossilised tree roots, some over 60 million years old. Previous weathering events have been recorded in magnetically remnant
ferruginous The adjective ferruginous may mean: * Containing iron, applied to water, oil, and other non-metals * Having rust on the surface * With the rust (color) See also * Ferrous, containing iron (for metals and alloys) or iron(II) cations * Ferric, cont ...
laterite of a
Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...
age, at about 180 Ma. The regolith of the Yilgarn impacts directly on the flora and fauna, as some of the soil is essentially fossilised. Much of the groundwater of the Yilgarn is hypersaline, with some being supersaturated in salt. This renders swathes of land barren, with significant salt lakes, and high saline water tables. The origin of this salt is thought to be from precipitation of sea salt carried over the Australian landmass for the past several dozen million years, and the high evaporation rate leaving the salt behind. The greenstone belts of the Yilgarn Craton include: * Southern Cross Greenstone Belt * Norseman-Wiluna Belt * Duketon Belt * Gullewa Greenstone Belt


Economic geology

The Yilgarn Craton is Australia's premier mineral province. It attracts more than half of Australia's minerals exploration expenditure, and produces two thirds of all gold and most of the nickel mined in Australia. The craton contains some 30% of the world's known gold reserves, about 20% of the world's
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 ...
reserves, 80% of the world's
tantalum Tantalum is a chemical element with the symbol Ta and atomic number 73. Previously known as ''tantalium'', it is named after Tantalus, a villain in Greek mythology. Tantalum is a very hard, ductile, lustrous, blue-gray transition metal that ...
reserves, considerable
iron ore Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in color from dark grey, bright yellow, or deep purple to rusty red. The iron is usually found in the fo ...
,
copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
,
zinc Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...
and minor
lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...
reserves. The craton contains significant
platinum Platinum is a chemical element with the symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Its name originates from Spanish , a diminutive of "silver". Pla ...
,
vanadium Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery-grey, malleable transition metal. The elemental metal is rarely found in nature, but once isolated artificially, the formation of an oxide layer ( pas ...
, hard-rock
titanium Titanium is a chemical element with the symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...
and considerable iron ore resources.
Mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic via ...
is conducted mostly in the greenstone belts around mining centres such as Kalgoorlie,
Kambalda Kambalda is a small mining town about from the mining city of Kalgoorlie in Western Australia, within the Goldfields. It is split into two townsites apart, Kambalda East and Kambalda West; and is located on the western edge of a giant salt ...
, Norseman, Meekatharra and Wiluna, and minor centres such as Laverton,
Leinster Leinster ( ; ga, Laighin or ) is one of the provinces of Ireland, situated in the southeast and east of Ireland. The province comprises the ancient Kingdoms of Meath, Leinster and Osraige. Following the 12th-century Norman invasion of Ir ...
, Leonora and
Southern Cross Crux () is a constellation of the southern sky that is centred on four bright stars in a cross-shaped asterism commonly known as the Southern Cross. It lies on the southern end of the Milky Way's visible band. The name ''Crux'' is Latin for ...
. Ore concentrates or finished product are transported by rail or road to
Perth Perth is the capital and largest city of the Australian state of Western Australia. It is the fourth most populous city in Australia and Oceania, with a population of 2.1 million (80% of the state) living in Greater Perth in 2020. Perth i ...
, Fremantle, Esperance, Albany or
Geraldton Geraldton ( Wajarri: ''Jambinu'', Wilunyu: ''Jambinbirri'') is a coastal city in the Mid West region of the Australian state of Western Australia, north of the state capital, Perth. At June 2018, Geraldton had an urban population of 37,648. ...
.


Iron ore

Iron ore Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in color from dark grey, bright yellow, or deep purple to rusty red. The iron is usually found in the fo ...
is currently recovered from several areas in the Yilgarn Craton, although it is a much smaller set of mines than those in the
Pilbara Craton The Pilbara Craton is an old and stable part of the continental lithosphere located in the Pilbara region of Western Australia. The Pilbara Craton is one of only two pristine Archaean 3.6–2.7 Ga (billion years ago) crusts identified on the ...
. Iron ore is mined at Koolyanobbing, north of Kalgoorlie from hematite weathered
banded iron formation Banded iron formations (also known as banded ironstone formations or BIFs) are distinctive units of sedimentary rock consisting of alternating layers of iron oxides and iron-poor chert. They can be up to several hundred meters in thickness ...
, at Mount Gibson, Weld Range and
Jack Hills The Jack Hills are a range of hills in Mid West Western Australia. They are best known as the source of the oldest material of terrestrial origin found to date: Hadean zircons that formed around 4.39 billion years ago. These zircons have enabl ...
in the Western Gneiss Terrane from hematite banded iron formation to produce direct-shipping ore. The Karara Iron Ore Project is the only operational magnetite mine in the Yilgarn Craton, however, other magnetite iron ore deposits are being investigated as a source of
magnetite Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe2+Fe3+2O4. It is one of the oxides of iron, and is ferrimagnetic; it is attracted to a magnet and can be magnetized to become a permanent magnet itself. With th ...
ore in the Albany-Fraser Complex, where a large deposit is being proposed at Southdown. The Jack Hills, Weld Range and Mount Gibson banded iron formations, as well as banded iron formations around Yalgoo, are also considered potential sources of magnetite iron ore, although no operations are as yet running on this type of ore. Further away from the coast, deposits of banded iron formation at Wiluna and Laverton are also under investigation, although infrastructure is considered too poor to render these deposits economic.


Gold

The Yilgarn Craton is host to around 4% of the world's economically demonstrably recoverable reserves (EDR) of gold. Major gold deposits occur at Kalgoorlie, Kambalda, Mount Magnet, Boddington, Laverton and Wiluna, and are hosted in greenstone belts. These form linear belts of mafic, ultramafic and felsic volcanics, intercalated with sedimentary sequences, and have been deformed and metamorphosed. The mode of occurrence of the gold mineralisation tends to be small- to medium-sized structurally controlled lodes, shears, and quartz veins. A key feature beneath many of the region's gold deposits are granite-cored domes at a range of scales. These provided an architecture that focussed fluid metals into the upper crust's depositional sites. Signatures of the mantle are found in many large deposits, including melts from metasomatised mantle wedge as well as lamprophyres. Debate continues whether these mantle rocks were a fluid and/or metal source, or simply reflect a favourable pathway.


Nickel-PGE deposits

The greater Kambalda district hosts a world-class nickel-sulfide mining district with a total pre-mining resource of 2 megatons (Mt) of nickel metal. Approximately 1.1 Mt of nickel metal has been produced since 1967, at an average rate of 35,000 tons of nickel per year. The Kambalda Dome is located in the south-central part of the Archaean Norseman-Wiluna greenstone belt in the southeastern Yilgarn Craton.
Kambalda type komatiitic nickel ore deposits Kambalda type komatiitic nickel ore deposits are a class of magmatic iron-nickel-copper-platinum-group element ore deposit in which the physical processes of komatiite volcanology serve to deposit, concentrate and enrich a Fe-Ni-Cu-(PGE) sulfide ...
are the primary source of nickel metal within the Yilgarn Craton.Hill R. E. T, Barnes S. J., Gole M. J., and Dowling S. E., 1990. ''Physical volcanology of komatiites; A field guide to the komatiites of the Norseman-Wiluna Greenstone Bel, Eastern Goldfields Province, Yilgarn Block, Western Australia'', Geological Society of Australia. .


Base metals

Copper, lead and zinc are currently mined from Golden Grove and the newly developed Jaguar zinc mine. Minor amounts of copper have been recovered from several copper-bearing gold deposits such as those in the Gullewa Greenstone Belt, at Burtville south of Laverton, at Granny Smith and elsewhere. The desert area encircling Kalgoorlie, with an area of 500,000 square kilometres, is theorised to host a 100 million tonne copper-zinc deposit. The geology of several volcanic belts in the Yilgarn Craton are strikingly similar to the world's great base-metal mines at
Kidd Creek Kidd Mine or Kidd Creek Mine is an underground base metal mine north of Timmins, Ontario, Canada. It is owned and operated by Swiss multinational Glencore Inc. The mine was discovered in 1963 by Texas Gulf Sulfur Company. In 1981 it was sold to ...
in Northern
Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...
,
Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
. Exploration for copper is continuing in several areas around Ravensthorpe, Balagundi, in the Yandall Belt, and the Duketon Belt, where large felsic volcanic packages are known to exist.


Rare-earth elements

The Yilgarn Craton may host up to 60% of the world's recoverable
rare-earth element The rare-earth elements (REE), also called the rare-earth metals or (in context) rare-earth oxides or sometimes the lanthanides ( yttrium and scandium are usually included as rare earths), are a set of 17 nearly-indistinguishable lustrous silv ...
s, primarily in the
Mount Weld Mount Weld mine is a rare earth mine in Western Australia, located about south of Laverton and east of Leonora. It ranks as one of the richest major rare-earth deposits in the world. Rare earths are contained in secondary phosphates and a ...
Carbonatite Carbonatite () is a type of intrusive or extrusive igneous rock defined by mineralogic composition consisting of greater than 50% carbonate minerals. Carbonatites may be confused with marble and may require geochemical verification. Carbonati ...
. Smaller carbonatite occurrences at Ponton, near Laverton, and regionally within the eastern granite-gneiss and greenstone belts, may also prove economic.


Uranium

The Yilgarn Craton and its cover sequences are host to a significant percentage of the world's endowment in economically demonstrable and recoverable reserves (EDR) of uranium. Most uranium is hosted within palaeochannels derived from granites of the Yilgarn Craton and/or its flanking Proterozoic orogens, and this metal is deposited within Tertiary or younger palaeodrainage and current drainage systems. Examples include Yeelirrie, Mulga Rock and Lake Way-Centipede.


Partial list of ore deposits and mines

World-class deposits in the eastern Yilgarn Craton include: Mount Charlotte, Norseman, Sunrise Dam,
Sons of Gwalia Sons of Gwalia was a Western Australian mining company that mined gold, tantalum, spodumene, lithium and tin. It was Australia's third-largest gold producer and also controlled more than half the world's production of tantalum,St Ives-Kambalda, Tarmoola,
Wallaby A wallaby () is a small or middle-sized macropod native to Australia and New Guinea, with introduced populations in New Zealand, Hawaii, the United Kingdom and other countries. They belong to the same taxonomic family as kangaroos and som ...
and Wiluna. World-class nickel deposits include: Mount Keith, Kambalda and * Cosmos Nickel Projects, Cosmos Pit, Cosmos Deeps, Alec Mairs and Tapinos high-grade massive sulphides. * Murrin Murrin lateritic nickel. *
Kambalda Kambalda is a small mining town about from the mining city of Kalgoorlie in Western Australia, within the Goldfields. It is split into two townsites apart, Kambalda East and Kambalda West; and is located on the western edge of a giant salt ...
nickel mines, Kambalda Dome and Widgiemooltha * Miitel, Mariners, Redross and Wannaway nickel mines,
Widgiemooltha Dome The Widgiemooltha Komatiite is a formation of komatiite in the Yilgarn Craton of Western Australia. Stratigraphy The stratigraphy of the Widgiemooltha Komatiite is well known to be part of the regional komatiite magmatic event also seen at the ...
*
Emily Ann and Maggie Hays nickel mines The Emily Ann and Maggie Hays nickel deposits are situated 117 km west of the town of Norseman, Western Australia, within the Lake Johnston Greenstone Belt.Hill R.E.T, Barnes S.J., Gole M.J., and Dowling S.E., 1990. ''Physical volcanology ...
, Lake Johnston Greenstone Belt * Super Pit or Fimiston Open Cut, Kalgoorlie * Golden Grove Mine Cu-Zn-Au mine *
Bronzewing Gold Mine The Bronzewing Gold Mine is a gold mine located approximately 83 km north-east of Leinster, Western Australia. The mine, owned by Navigator Resources Limited, has been in care and maintenance since March 2013, after its owner went into adm ...
* Jundee-Nimary Gold Mine * Kanowna Belle Gold Mine * Windimurra vanadium resource,
Windimurra Intrusion The Windimurra Igneous Complex is a giant ultramafic-mafic intrusion emplaced within the Yilgarn craton of Western Australia. It is located approximately 100 kilometres south east of the town of Mount Magnet. Setting The Windimurra Igneous Compl ...
,
Mount Magnet Mount is often used as part of the name of specific mountains, e.g. Mount Everest. Mount or Mounts may also refer to: Places * Mount, Cornwall, a village in Warleggan parish, England * Mount, Perranzabuloe, a hamlet in Perranzabuloe parish, C ...
* Greenbushes Lithium mine * Mt Cattlin Lithium-Tantalum mine * Bald Hill Lithium and Tantalum Mine


See also

* * * * * * * * *


References

{{Physical geography topics Geology of Western Australia Archean Precambrian Australia Economic geology Cratons Structural geology Historical geology Physiographic provinces