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The various theories of ore genesis explain how the various types of mineral deposits form within the Earth's crust. In Geology, a crust is the outermost solid shell of a planet or moon Ore genesis theories are very dependent on the mineral or commodity. A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific

Ore genesis theories generally involve three components: source, transport or conduit, and trap. This also applies to the petroleum industry, which was first to use this methodology. Petroleum ( L petroleum, from Greek πετρέλαιον, lit

The biggest deposits are formed when the source is large, the transport mechanism is efficient, and the trap is active and ready at the right time. An ore is a volume of rock containing components or Minerals in a mode of occurrence that renders it valuable for mining

Contents

Ore genesis processes

Evans (1993) divides ore genesis into the following main categories based on physical process. These are internal processes, hydrothermal processes, metamorphic processes and surficial processes.

Internal processes

These processes are integral physical phenomena and chemical reactions internal to magmas, generally in plutonic or volcanic rocks. Igneous rocks (etymology from Latin ignis, fire are rocks formed by solidification of cooled Magma (molten rock Igneous rocks (etymology from Latin ignis, fire are rocks formed by solidification of cooled Magma (molten rock These include;

Hydrothermal processes

These processes are the physico-chemical phenomena and reactions caused by movement of hydrothermal waters within the crust, often as a consequence of magmatic intrusion or tectonic upheavals. Hydrothermal circulation in its most general sense is the circulation of hot water 'hydros' in the Greek meaning water and 'thermos' meaning heat The foundations of hydrothermal processes are the source-transport-trap mechanism.

Sources of hydrothermal solutions include seawater, formational brines (water trapped within sediments at deposition) and metamorphic fluids created by dehydration of hydrous minerals during metamorphism. Brine (lat saltus) is Water saturated or nearly saturated with Salt (NaCl Metamorphism can be defined as the solid state recrystallisation of pre-existing rocks due to changes in heat and/or pressure and/or introduction of fluids i

Metal sources may include a plethora of rocks. However most metals of economic importance are carried as trace elements within rock-forming minerals, and so may be liberated by hydrothermal processes. This happens because of

Transport by hydrothermal solutions usually requires a salt or other soluble species which can form a metal-bearing complex. Halite is the Mineral form of Sodium chloride, Na[[chlorine Cl]] commonly known as rock salt. Cerussite (also known as lead carbonate or White lead ore) is a Mineral consisting of Lead Carbonate (PbCO3 In Geology, the Mineral monazite is a reddish-brown Phosphate -containing rare earth metals and an important source of Thorium Thorianite is a rare mineral originally discovered by Ananda Coomaraswamy in 1904 as uraninite but recognized as a new species by W Baryte ( Ba[[Sulfur S]] O 4 is a Mineral consisting of Barium sulfate. These metal-bearing complexes facilitate transport of metals within aqueous solutions, generally as hydroxides, but also by processes similar to chelation. Chelation is the binding or complexation of a bi- or multidentate Ligand.
This process is especially well understood in gold metallogeny where various thiosulfate, chloride and other gold-carrying chemical complexes (notably tellurium-chloride/sulfate or antimony-chloride/sulfate). Tellurium (tɪˈlʊəriəm/ /tɛl- is a Chemical element that has the symbol Te and Atomic number 52 The majority of metal deposits formed by hydrothermal processes include sulfide minerals, indicating sulfur is an important metal-carrying complex. The term sulfide ( sulphide in British English) refers to several types of Chemical compounds containing Sulfur in its lowest Oxidation

Sulfide deposition:
Sulfide deposition within the trap zone occurs when metal-carrying sulfate, sulfide or other complexes become chemically unstable due to one or more of the following processes;

Metal can also become precipitated when temperature and pressure or oxidation state favour different ionic complexes in the water, for instance the change from sulfide to sulfate, oxygen fugacity, exchange of metals between sulfide and chloride complexes, et cetera. In Chemistry, the oxidation state is an indicator of the degree of Oxidation of an Atom in a Chemical compound. Mafic is an adjective describing a Silicate mineral or rock that is rich in magnesium and iron the term was derived by contracting "magnesium" and "ferric" Ultramafic (also referred to as ultrabasic) rocks are igneous and meta -igneous rocks with very low Silica content (less than 45% generally In Chemistry, a carbonate is a salt or Ester of Carbonic acid. Fugacity is a measure of a Chemical potential in the form of 'adjusted pressure

Metamorphic processes

Lateral secretion:
Ore deposits formed by lateral secretion are formed by metamorphic reactions during shearing, which liberate mineral constituents such as quartz, sulfides, gold, carbonates and oxides from deforming rocks and focus these constituents into zones of reduced pressure or dilation such as faults. Study of geological shear is related to the study of Structural geology, Rock microstructure or rock texture and fault mechanics. In Geology a fault, or fault line, is a planar rock fracture which shows evidence of relative movement This may occur without much hydrothermal fluid flow, and this is typical of podiform chromite deposits.

Metamorphic processes also control many physical processes which form the source of hydrothermal fluids, outlined above.

Surficial processes

Surficial processes are the physical and chemical phenomena which cause concentration of ore material within the regolith, generally by the action of the environment. Regolith ( Greek: "blanket rock" is a layer of loose Heterogeneous material covering solid rock. This includes placer deposits, laterite deposits and residual or eluvial deposits. Placer mining (pronounced "plass-er" refers to the mining of alluvial deposits for Minerals This may be done by open-pit (also called open-cast Laterite (from the Latin word "later" meaning brick or tile is a surface formation in hot and wet tropical areas which is enriched in Iron and Aluminium In Geology, eluvium or eluvial deposits are those geological deposits and Soils that are derived by in situ Weathering or weathering The physical processes of ore deposit formation in the surficial realm include;

Classification of ore deposits

Ore deposits are usually classified by ore formation processes and geological setting. Erosion is the carrying away or displacement of solids ( Sediment, Soil, rock and other particles usually by the agents of currents such as wind Wind winnowing is an agricultural method developed by ancient cultures for separating grain from Chaff. Weathering is the decomposition of earth rocks, Soils and their Minerals through direct contact with the planet's Atmosphere. Manto orebodies are stratabound irregular to rod shaped Ore occurrences usually horizontal or near horizontal in attitude For example, SEDEX deposits, literally meaning "sedimentary exhalative" are a class of ore deposit formed on the sea floor (sedimentary) by exhalation of brines into seawater (exhalative), causing chemical precipitation of ore minerals when the brine cools, mixes with sea water and loses its metal carrying capacity. Sedimentary exhalative deposits (abbreviated as SEDEX from SED imentary EX halative are Ore deposits which are interpreted to have been formed by release

Ore deposits rarely fit snugly into the boxes in which geologists wish to place them. Many may be formed by one or more of the basic genesis processes above, creating ambiguous classifications and much argument and conjecture. Often ore deposits are classified after examples of their type, for instance Broken Hill Type lead-zinc-silver deposits or Carlin-type Gold deposits. For the Local Government Area of Broken Hill see City of Broken Hill Broken Hill is an isolated Mining city and Local Government Area Carlin is a town located near the western border of Elko County in northeast Nevada, 23 miles (37 km west of the city of Elko.

Classification of hydrothermal ore deposits is also achieved by classifying according to the temperature of formation, which roughly also correlates with particular mineralising fluids, mineral associations and structural styles. This scheme, proposed by Waldemar Lindgren (1933) classified hydrothermal deposits as hypothermal, mesothermal, epithermal and telethermal. Waldemar Lindgren ( February 14 1860 - November 3 1939) was a Swedish-American economic geologist.

Genesis of common ores

This page has been organised by metal commodity; it is also possible to organise theories according to geological criteria of formation, as well as by metal association. The M acro E xpansion T emplate A ttribute L anguage complements TAL, providing macros which allow the reuse of code across A commodity is anything for which there is demand but which is supplied without qualitative differentiation across a market Geology (from Greek γη gê, "earth" and λόγος Logos, "speech" lit Often ores of the same metal can be formed by multiple processes, and this is described by commodity.

Iron

Main article: Iron ore

Iron ores are overwhelmingly derived from ancient sediments known as banded iron formations (BIFs). Iron ores are rocks and Minerals from which Metallic Iron can be economically extracted Sediment is any particulate matter that can be transported by fluid flow and which eventually is deposited as a layer of solid particles on the bed or bottom of a body of Banded iron formations (also known as banded ironstone formations or BIF s are a distinctive type of rock often found in primordial ( Precambrian) Sedimentary These sediments are composed of iron oxide minerals deposited on the sea floor. Altogether there are sixteen known Iron Oxides and oxyhydroxides Particular environmental conditions are needed to transport enough iron in sea water to form these deposits, such as acidic and oxygen-poor atmospheres within the Proterozoic Era. The Proterozoic (ˌproʊtərəˈzoʊɪk is a geological eon representing a period before the first abundant complex life on Earth.

Often, more recent weathering during the Tertiary or Eocene is required to convert the usual magnetite minerals into more easily processed hematite. Weathering is the decomposition of earth rocks, Soils and their Minerals through direct contact with the planet's Atmosphere. The chuprichondira geological time interval covers roughly the time span between the demise of the non- avian Dinosaurs and beginning of the most recent Ice Age, approximately The Eocene epoch (558 ± 02 - 339 ± 01 Ma) is a major division of the Geologic timescale and the second epoch of the Palaeogene period in Magnetite is not to be confused with Magnesite or Maghemite. Magnetite is a ferrimagnetic Mineral with chemical Hematite, also spelt hæmatite, is the Mineral form of Iron(III oxide (Fe2O3 one of several Iron oxides Some iron deposits within the Pilbara of West Australia are placer deposits, formed by accumulation of hematite gravels called pisolites which form channel-iron deposits. For the Fly Genus, see Pilbara (fly. The Pilbara is a Western Australia is a state occupying the entire western third of the Australian continent. Channel iron deposits, also known as pisolitic iron ore are a major source of cheap high grade Iron ore exploited primarily in the Pilbara and Murchison These are preferred because they are cheap to mine.

Lead zinc silver

Main article: Sedimentary exhalative deposits
Main article: Carbonate hosted lead zinc ore deposits

Lead-zinc deposits are generally accompanied by silver, hosted within the lead sulfide mineral galena or within the zinc sulfide mineral sphalerite. Sedimentary exhalative deposits (abbreviated as SEDEX from SED imentary EX halative are Ore deposits which are interpreted to have been formed by release Carbonate-hosted lead-zinc ore deposits are important and highly valuable concentrations of lead and zinc sulfide Ores hosted within carbonate ( Limestone Characteristics Lead has a dull luster and is a dense, Ductile, very soft highly Zinc (ˈzɪŋk from Zink is a Metallic Chemical element with the symbol Zn and Atomic number 30 Silver (ˈsɪlvɚ is a Chemical element with the symbol " Ag " (argentum from the Ancient Greek: ἀργήντος - argēntos gen Galena is the natural mineral form of Lead sulfide. It is the most important Lead Ore mineral Sphalerite (( Zn, Fe) S) is a Mineral that is the chief Ore of Zinc.

Lead and zinc deposits are formed by discharge of deep sedimentary brine onto the sea floor (termed sedimentary exhalative or SEDEX), or by replacement of limestone, in skarn deposits, some associated with submarine volcanoes (called volcanogenic massive sulfide ore deposits or VMS) or in the aureole of subvolcanic intrusions of granite. Brine (lat saltus) is Water saturated or nearly saturated with Salt (NaCl Sedimentary exhalative deposits (abbreviated as SEDEX from SED imentary EX halative are Ore deposits which are interpreted to have been formed by release Limestone is a Sedimentary rock composed largely of the Mineral Calcite ( Calcium carbonate: CaCO3 Skarn is a Metamorphic rock that is usually variably colored green or red occasionally grey black brown or white Volcanogenic massive sulfide ore deposits or VMS are a type of Metal Sulfide ore deposit, mainly Cu - Zn which are associated with and An aureola or aureole (diminutive of Latin aurea, "golden" is the radiance of luminous cloud which in Paintings of sacred personages The vast majority of SEDEX lead and zinc deposits are Proterozoic in age, although there are significant Jurassic examples in Canada and Alaska. The Proterozoic (ˌproʊtərəˈzoʊɪk is a geological eon representing a period before the first abundant complex life on Earth.

The carbonate replacement type deposit is exemplified by the Mississippi valley type (MVT) ore deposits. Carbonate-hosted lead-zinc ore deposits are important and highly valuable concentrations of lead and zinc sulfide Ores hosted within carbonate ( Limestone MVT and similar styles occur by replacement and degradation of carbonate sequences by hydrocarbons, which are thought important for transporting lead. In Organic chemistry, a hydrocarbon is an Organic compound consisting entirely of Hydrogen and Carbon.

Gold

Gold deposits are formed via a very wide variety of geological processes. Geology (from Greek γη gê, "earth" and λόγος Logos, "speech" lit Deposits are classified as primary, alluvial or placer deposits, or residual or laterite deposits. Placer mining (pronounced "plass-er" refers to the mining of alluvial deposits for Minerals This may be done by open-pit (also called open-cast Laterite (from the Latin word "later" meaning brick or tile is a surface formation in hot and wet tropical areas which is enriched in Iron and Aluminium Often a deposit will contain a mixture of all three types of ore.

Plate tectonics is the underlying mechanism for generating gold deposits. Plate tectonics (from Greek τέκτων tektōn "builder" or "mason" describes the large scale motions of Earth 's Lithosphere The majority of primary gold deposits fall into two main categories: lode gold deposits or intrusion-related deposits. In Geology a lode is the metalliferous Ore that fills a Fissure in a rock or a vein of ore deposited between layers of In Geology, an intrusion is a body of Igneous rock that has Crystallized from molten Magma below the surface of the Earth.

Lode gold deposits are generally high-grade, thin, vein and fault hosted. They are comprised primarily of quartz veins also known as lodes or reefs, which contain either native gold or gold sulfides and tellurides. Quartz (from German) is the most abundant Mineral in the Earth 's Continental crust (although Feldspar is more common in The term sulfide ( sulphide in British English) refers to several types of Chemical compounds containing Sulfur in its lowest Oxidation Lode gold deposits are usually hosted in basalt or in sediments known as turbidite, although when in faults, they may occupy intrusive igneous rocks such as granite. Basalt (bəˈsɔːlt ˈbeisɔːlt ˈbæsɔːlt is a common Extrusive Volcanic rock. Turbidite Geological formations have their origins in Turbidity current deposits, which are deposits from a form of underwater Avalanche that In Geology a fault, or fault line, is a planar rock fracture which shows evidence of relative movement Granite (ˈɡrænɪt is a common and widely occurring type of intrusive, Felsic, igneous rock.

Lode-gold deposits are intimately associated with orogeny and other plate collision events within geologic history. Orogeny (Greek for "mountain generating" is the process of natural Mountain building and may be studied as a tectonic structural event as a geographical event and Most lode gold deposits sourced from metamorphic rocks because it is thought that the majority are formed by dehydration of basalt during metamorphism. Metamorphic rock is the result of the transformation of an existing rock type the protolith, in a process called Metamorphism, which means "change Dehydration ( hypohydration) is the removal of Water ( hydro in ancient Greek) from an object Basalt (bəˈsɔːlt ˈbeisɔːlt ˈbæsɔːlt is a common Extrusive Volcanic rock. The gold is transported up faults by hydrothermal waters and deposited when the water cools too much to retain gold in solution. Hydrothermal circulation in its most general sense is the circulation of hot water 'hydros' in the Greek meaning water and 'thermos' meaning heat

Intrusive related gold (Lang & Baker, 2001) is generally hosted in granites, porphyry or rarely dikes. Porphyry is a variety of Igneous rock consisting of large-grained Crystals such as Feldspar or Quartz, dispersed in a fine-grained A dike or dyke in Geology is a type of Sheet intrusion referring to any geologic body that cuts Discordantly ' across planar Intrusive related gold usually also contains copper, and is often associated with tin and tungsten, and rarely molybdenum, antimony and uranium. Copper (ˈkɒpɚ is a Chemical element with the symbol Cu (cuprum and Atomic number 29 Tin is a Chemical element with the symbol Sn (stannum and Atomic number 50 Tungsten (ˈtʌŋstən also known as wolfram (/ˈwʊlfrəm/ is a Chemical element that has the symbol W and Atomic number 74 Molybdenum (məˈlɪbdənəm from the Greek word for the metal " Lead " is a Group 6 Chemical element with the symbol Mo Antimony (IPA (Received Pronunciation, /ˈæntɪmoʊni/ (US is a Chemical element with the symbol Sb (stibium meaning "mark" and Uranium (jʊˈreɪniəm is a silvery-gray Metallic Chemical element in the Intrusive-related gold deposits rely on gold existing in the fluids associated with the magma (White, 2001), and the inevitable discharge of these hydrothermal fluids into the wall-rocks (Lowenstern, 2001). Magma (Plurals magmas and magmata) is molten rock that sometimes forms beneath the surface of the Earth (or any other Terrestrial planet Hydrothermal circulation in its most general sense is the circulation of hot water 'hydros' in the Greek meaning water and 'thermos' meaning heat Skarn deposits are another manifestation of intrusive-related deposits. Skarn is a Metamorphic rock that is usually variably colored green or red occasionally grey black brown or white

Placer deposits are sourced from pre-existing gold deposits and are secondary deposits. Placer deposits are formed by alluvial processes within rivers, streams and on beaches. Alluvium (from the Latin, alluvius, from alluere, "to wash against" is Soil or Sediments deposited by a river or other running Beaches (also known as Forever Friends) is a 1988 Academy Award -nominated movie adapted by Mary Agnes Donoghue from the Placer gold deposits form via gravity, with the density of gold causing it to sink into trap sites within the river bed, or where water velocity drops, such as bends in rivers and behind boulders. Gravitation is a natural Phenomenon by which objects with Mass attract one another The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different Often placer deposits are found within sedimentary rocks and can be billions of years old, for instance the Witwatersrand deposits in South Africa. The Witwatersrand is a low sedimentary range of hills at an elevation of 1700-1800 metres above sea-level which runs in an east-west direction through Gauteng in The Republic of South Africa (also known by other official names) is a country located at the southern tip of the continent of Africa Sedimentary placer deposits are known as 'leads' or 'deep leads'.

Placer deposits are often worked by fossicking, and panning for gold is a popular pastime. Fossicking is a term found in Cornwall and Australia referring to Prospecting.

Laterite gold deposits are formed from pre-existing gold deposits (including some placer deposits) during prolonged weathering of the bedrock. Laterite (from the Latin word "later" meaning brick or tile is a surface formation in hot and wet tropical areas which is enriched in Iron and Aluminium Gold is deposited within iron oxides in the weathered rock or regolith, and may be further enriched by reworking by erosion. Altogether there are sixteen known Iron Oxides and oxyhydroxides Regolith ( Greek: "blanket rock" is a layer of loose Heterogeneous material covering solid rock. Some laterite deposits are formed by wind erosion of the bedrock leaving a residuum of native gold metal at surface.

Platinum

Platinum and palladium are precious metals generally found in ultramafic rocks. Ultramafic (also referred to as ultrabasic) rocks are igneous and meta -igneous rocks with very low Silica content (less than 45% generally The source of platinum and palladium deposits is ultramafic rocks which have enough sulfur to form a sulfide mineral while the magma is still liquid. Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16 The term sulfide ( sulphide in British English) refers to several types of Chemical compounds containing Sulfur in its lowest Oxidation This sulfide mineral (usually pentlandite, pyrite, chalcopyrite or pyrrhotite) gains platinum by mixing with the bulk of the magma because platinum is chalcophile and is concentrated in sulfides. Pentlandite is an Iron - Nickel sulfide ( Fe, Ni)9 S 8 Pentlandite usually has a NiFe ratio of close to 11 Chalcopyrite (ˌkælkoʊˈpaɪraɪt kal-co-pie-right —"kal" as in " cal endar" "co" as in co de is a Copper Pyrrhotite is an unusual Iron Sulfide mineral with a variable iron content Fe(1-xS (x = 0 to 0 The Goldschmidt classification, developed by Victor Goldschmidt, is a geochemical classification which groups the Chemical elements according to their preferred Alternatively, platinum occurs in association with chromite either within the chromite mineral itself or within sulfides associated with it. Chromite is iron magnesium chromium oxide (Fe MgCr2O4 It is an Oxide Mineral belonging to the Spinel group

Sulfide phases only form in ultramafic magmas when the magma reaches sulfur saturation. This is generally thought to be nearly impossible by pure fractional crystallisation, so other processes are usually required in ore genesis models to explain sulfur saturation. These include contamination of the magma with crustal material, especially sulfur-rich wall-rocks or sediments; magma mixing; volatile gain or loss.

Often platinum is associated with nickel, copper, chromium, and cobalt deposits. Platinum (ˈplætɪnəm is a Chemical element with the Atomic symbol Pt and an Atomic number of 78 Nickel (ˈnɪkəl is a metallic Chemical element with the symbol Ni and Atomic number 28 Copper (ˈkɒpɚ is a Chemical element with the symbol Cu (cuprum and Atomic number 29 Chromium (ˈkroʊmiəm is a Chemical element which has the symbol Cr and Atomic number 24 Cobalt (ˈkoʊbɒlt is a hard lustrous silver-grey Metal, a Chemical element with symbol Co.

Nickel

Main article: Kambalda type komatiitic nickel ore deposits
Main article: Lateritic nickel ore deposits

Nickel deposits are generally found in two forms, either as sulfide or laterite. Kambalda type nickel ore deposits are a class of magmatic Nickel - Copper Ore deposit in which the physical processes of Komatiite volcanology Lateritic nickel ore deposits are surficial Weathered rinds formed on Ultramafic rocks

Sulfide type nickel deposits are formed in essentially the same manner as platinum deposits. Platinum (ˈplætɪnəm is a Chemical element with the Atomic symbol Pt and an Atomic number of 78 Nickel is a chalcophile element which prefers sulfides, so an ultramafic or mafic rock which has a sulfide phase in the magma may form nickel sulfides. The best nickel deposits are formed where sulfide accumulates in the base of lava tubes or volcanic flows — especially komatiite lavas. Lava tubes are natural conduits through which Lava travels beneath the surface of a lava flow expelled by a Volcano during an eruption Plate tectonics and hotspots Divergent plate boundaries At the Komatiites are Ultramafic mantle-derived Volcanic rocks They have low SiO2 low K2O low Al2O3 and high to extremely high

Komatiitic nickel-copper sulfide deposits are considered to be formed by a mixture of sulfide segregation, immiscibility, and thermal erosion of sulfidic sediments. The sediments are considered to be necessary to promote sulfur saturation.

Some subvolcanic sills in the Thompson Belt of Canada host nickel sulfide deposits formed by deposition of sulfides near the feeder vent. Sulfide was accumulated near the vent due to the loss of magma velocity at the vent interface. The massive Voisey's Bay nickel deposit is considered to have formed via a similar process. Voisey's Bay is a Canadian Bay in the province of Newfoundland and Labrador.

The process of forming nickel laterite deposits is essentially similar to the formation of gold laterite deposits, except that ultramafic or mafic rocks are required. Ultramafic (also referred to as ultrabasic) rocks are igneous and meta -igneous rocks with very low Silica content (less than 45% generally Mafic is an adjective describing a Silicate mineral or rock that is rich in magnesium and iron the term was derived by contracting "magnesium" and "ferric" Generally nickel laterites require very large olivine-bearing ultramafic intrusions. The Mineral olivine (when gem-quality also called Peridot) is a Magnesium Iron silicate with the formula ( Mg Minerals formed in laterite nickel deposits include gibbsite. Gibbsite, Al(OH3 is one of the mineral forms of Aluminium hydroxide.

Copper

Main article: Porphyry copper
Main article: Manto ore deposits

Copper is found in association with many other metals and deposit styles. Porphyry copper deposits are Copper Orebodies which are associated with porphyritic Intrusive rocks Manto orebodies are stratabound irregular to rod shaped Ore occurrences usually horizontal or near horizontal in attitude Commonly, copper is either formed within sedimentary rocks, or associated with igneous rocks. Igneous rocks (etymology from Latin ignis, fire are rocks formed by solidification of cooled Magma (molten rock

The world's major copper deposits are formed within the granitic porphyry copper style. Porphyry copper deposits are Copper Orebodies which are associated with porphyritic Intrusive rocks Copper is enriched by processes during crystallisation of the granite and forms as chalcopyrite — a sulfide mineral, which is carried up with the granite. Chalcopyrite (ˌkælkoʊˈpaɪraɪt kal-co-pie-right —"kal" as in " cal endar" "co" as in co de is a Copper

Sometimes granites erupt to suface as volcanoes, and copper mineralisation forms during this phase when the granite and volcanic rocks cool via hydrothermal circulation. Plate tectonics and hotspots Divergent plate boundaries At the Hydrothermal circulation in its most general sense is the circulation of hot water 'hydros' in the Greek meaning water and 'thermos' meaning heat

Sedimentary copper forms within ocean basins in sedimentary rocks. Generally this forms by brine from deeply buried sediments discharging into the deep sea, and precipitating copper and often lead and zinc sulfides directly onto the sea floor. Brine (lat saltus) is Water saturated or nearly saturated with Salt (NaCl Characteristics Lead has a dull luster and is a dense, Ductile, very soft highly Zinc (ˈzɪŋk from Zink is a Metallic Chemical element with the symbol Zn and Atomic number 30 This is then buried by further sediment.

Often copper is associated with gold, lead, zinc and nickel deposits. Gold (ˈɡoʊld is a Chemical element with the symbol Au (from its Latin name aurum) and Atomic number 79 Characteristics Lead has a dull luster and is a dense, Ductile, very soft highly Zinc (ˈzɪŋk from Zink is a Metallic Chemical element with the symbol Zn and Atomic number 30 Nickel (ˈnɪkəl is a metallic Chemical element with the symbol Ni and Atomic number 28

Uranium

Main article: Uranium ore deposits

Uranium deposits are usually sourced from radioactive granites, where certain minerals such as monazite are leached during hydrothermal activity or during circulation of groundwater. Uranium ore deposits are Ore deposits which constitute economically recoverable concentrations of Uranium within the Earth's crust Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. In Geology, the Mineral monazite is a reddish-brown Phosphate -containing rare earth metals and an important source of Thorium Hydrothermal circulation in its most general sense is the circulation of hot water 'hydros' in the Greek meaning water and 'thermos' meaning heat Groundwater is Water located beneath the Ground surface in Soil pore spaces and in the Fractures of lithologic formations The uranium is brought into solution by acidic conditions and is deposited when this acidity is neutralised. Generally this occurs in certain carbon-bearing sediments, within an unconformity in sedimentary strata. An unconformity is a buried Erosion surface separating two rock masses or strata of different ages indicating that Sediment deposition was not The majority of the world's nuclear power is sourced from uranium in such deposits. Nuclear power is any Nuclear technology designed to extract usable Energy from atomic nuclei via controlled Nuclear reactions

Uranium is also found in nearly all coal at several parts per million, and in all granites. "Parts-per" notation is used especially in Science and Engineering, to denote Ratios (relative proportions in measured quantities particularly Radon is a common problem during mining of uranium as it is a radioactive gas. Radon (ˈreɪdɒn is the Chemical element that has the symbol Rn and Atomic number 86

Uranium is also found associated with certain igenous rocks, such as granite and porphyry. Granite (ˈɡrænɪt is a common and widely occurring type of intrusive, Felsic, igneous rock. Porphyry is a variety of Igneous rock consisting of large-grained Crystals such as Feldspar or Quartz, dispersed in a fine-grained The Olympic Dam deposit in Australia is an example of this type of uranium deposit. Olympic Dam is a mining centre in South Australia located some 550 km NNW of Adelaide the capital city of South Australia. It contains 70% of Australia's share of 40% of the known global low-cost recoverable uranium inventory.

Titanium and zirconium

Main article: Heavy mineral sands ore deposits

Mineral sands are the predominant type of titanium, zirconium and thorium deposit. Heavy mineral Sands are a class of Ore deposit which is an important source of Zirconium, Titanium, Thorium, Tungsten, Titanium (taɪˈteɪniəm is a Chemical element with the symbol Ti and Atomic number 22 Zirconium (zɚˈkoʊniəm /ˌzɝˈkoʊniəm/ is a Chemical element with the symbol Zr and Atomic number 40 Thorium (ˈθɔːriəm is a Chemical element with the symbol Th and Atomic number 90 They are formed by accumulation of such heavy minerals within beach systems, and are a type of placer deposits. Heavy mineral Sands are a class of Ore deposit which is an important source of Zirconium, Titanium, Thorium, Tungsten, In Geology, a placer deposit or placer is an accumulation of valuable minerals formed by deposition of dense mineral phases in a trap site The minerals which contain titanium are ilmenite, rutile and leucoxene, zirconium is contained within zircon, and thorium is generally contained within monazite. Leucoxene is a fine Granular alteration product of Titanium Minerals It varies in color from yellow to brown Zircon is a Mineral belonging to the group of nesosilicates. Its chemical name is Zirconium silicate and its corresponding chemical formula is In Geology, the Mineral monazite is a reddish-brown Phosphate -containing rare earth metals and an important source of Thorium These minerals are sourced from primarily granite bedrock by erosion and transported to the sea by rivers where they accumulate within beach sands. Granite (ˈɡrænɪt is a common and widely occurring type of intrusive, Felsic, igneous rock. Erosion is the carrying away or displacement of solids ( Sediment, Soil, rock and other particles usually by the agents of currents such as wind "Riverine" redirects here For the use of that term in Maritime geography, see there Rarely, but importantly, gold, tin and platinum deposits can form in beach placer deposits. Gold (ˈɡoʊld is a Chemical element with the symbol Au (from its Latin name aurum) and Atomic number 79 Tin is a Chemical element with the symbol Sn (stannum and Atomic number 50 Platinum (ˈplætɪnəm is a Chemical element with the Atomic symbol Pt and an Atomic number of 78

Tin, tungsten, and molybdenum

These three metals generally form in a certain type of granite, via a similar mechanism to intrusive-related gold and copper. Granite (ˈɡrænɪt is a common and widely occurring type of intrusive, Felsic, igneous rock. They are considered together because the process of forming these deposits is essentially the same. Skarn type mineralisation related to these granites is a very important type of tin, tungsten and molybdenum deposit. Skarn is a Metamorphic rock that is usually variably colored green or red occasionally grey black brown or white Skarn deposits form by reaction of mineralised fluids from the granite reacting with wall rocks such as limestone. Limestone is a Sedimentary rock composed largely of the Mineral Calcite ( Calcium carbonate: CaCO3 Skarn mineralisation is also important in lead, zinc, copper, gold and occasionally uranium mineralisation. Characteristics Lead has a dull luster and is a dense, Ductile, very soft highly Zinc (ˈzɪŋk from Zink is a Metallic Chemical element with the symbol Zn and Atomic number 30 Copper (ˈkɒpɚ is a Chemical element with the symbol Cu (cuprum and Atomic number 29 Gold (ˈɡoʊld is a Chemical element with the symbol Au (from its Latin name aurum) and Atomic number 79 Uranium (jʊˈreɪniəm is a silvery-gray Metallic Chemical element in the

Greisen granite is another related tin-molybdenum and topaz mineralisation style. Greisen is a highly altered granitic rock or Pegmatite. Greisen is formed by autogenic alteration of a granite and is a class of endoskarn.

Rare earth elements, niobium, tantalum, lithium

The overwhelming majority of rare earth elements, tantalum and lithium are found within pegmatite. Rare earth elements and rare earth metals are according to IUPAC, the collection of seventeen Chemical elements in the Periodic table, namely Tantalum (ˈtæntələm (formerly tantalium /tænˈtæliəm/ is a Chemical element with the symbol Ta and Atomic number 73 Lithium (ˈlɪθiəm is a Chemical element with the symbol Li and Atomic number 3 Pegmatite is a very coarse-grained Igneous rock that has a grain size of 20 mm or more such rocks are referred to as pegmatitic. Ore genesis theories for these ores are wide and varied, but most involve metamorphism and igneous activity. Metamorphism can be defined as the solid state recrystallisation of pre-existing rocks due to changes in heat and/or pressure and/or introduction of fluids i Igneous rocks (etymology from Latin ignis, fire are rocks formed by solidification of cooled Magma (molten rock Lithium is present as spodumene or lepidolite within pegmatite. Lithium (ˈlɪθiəm is a Chemical element with the symbol Li and Atomic number 3 "Kunzite" redirects here For the Sailor Moon character see Shitennou. Lepidolite (KLi2Al(AlSi3O10(FOH2 is a lilac or rose-violet colored phyllosilicate Mineral of the Mica group

Carbonatite intrusions are an important source of these elements. Carbonatites (kɑrˈbɒnətaɪt are Intrusive or extrusive Igneous rocks defined by mineralogy that comprises more than 50 volume-% Carbonate Ore minerals are essentially part of the unusual mineralogy of carbonatite.

Phosphate

Phosphate is used in fertilisers. A phosphate, an Inorganic chemical, is a salt of Phosphoric acid. Immense quantities of phosphate rock or phosphorite occur in sedimentary shelf deposits, ranging in age from the Proterozoic to currently forming environments. A phosphorite or phosphate rock is a non-detrital Sedimentary rock which contains high amounts of Phosphate bearing minerals The Proterozoic (ˌproʊtərəˈzoʊɪk is a geological eon representing a period before the first abundant complex life on Earth. [1] Phosphate deposits are thought to be sourced from the skeletons of dead sea creatures which accumulated on the seafloor. Similar to iron ore deposits and oil, particular conditions in the ocean and environment are thought to have contributed to these deposits within the geological past.

Phosphate deposits are also formed from alkaline igneous rocks such as nepheline syenites, carbonatites and associated rock types. Nephelene syenite is a Holocrystalline plutonic rock that consists largely of Nepheline and Alkali Feldspar. Carbonatites (kɑrˈbɒnətaɪt are Intrusive or extrusive Igneous rocks defined by mineralogy that comprises more than 50 volume-% Carbonate The phosphate is, in this case, contained within magmatic apatite, monazite or other rare-earth phosphates. In Geology, the Mineral monazite is a reddish-brown Phosphate -containing rare earth metals and an important source of Thorium

See also

References

  1. ^ Guilbert, John M. Mineral exploration is the process undertaken by companies partnerships or corporations in the endeavour of finding Ore (commercially viable concentrations of minerals to Currently the most common source of Copper Ore is the mineral Chalcopyrite (CuFeS2 which accounts for about 50% of copper production Hydrothermal circulation in its most general sense is the circulation of hot water 'hydros' in the Greek meaning water and 'thermos' meaning heat Economic geology is concerned with earth materials that can be utilized for economic and/or industrial purposes In geology a redox buffer is an assemblage of minerals or compounds that constrains oxygen Fugacity as a function of temperature Metasomatism is the chemical alteration of a rock by Hydrothermal and other fluids Igneous differentiation is an umbrella term for the various processes by which Magmas undergo bulk chemical change during the Partial melting process cooling and Charles F. Park, The Geology of Ore Deposites, 1986, Freeman, pp. 715-720, ISBN 0-7167-1456-6

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