gibbsite

Cryolite (Na3AlF6, sodium aluminium fluoride) is an uncommon mineral of very limited natural distribution. It is mostly identified with the once large deposit at Ivigtût on the west coast of Greenland. It was historically used as an ore of aluminium and later in the electroytic processing of the aluminium rich oxide ore, bauxite, which is a combination of aluminium oxide minerals such as gibbsite, boehmite and diaspore. The difficulty of removing aluminium from oxygen in the oxide ores was overcome by the ...

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Bauxite is a naturally occurring, heterogeneous material composed primarily of one or more aluminium hydroxide minerals, plus various mixtures of silica, iron oxide, titania, aluminium silicates, and other impurities in minor or trace amounts. Bauxite is a sedimentary rock produced by in situ chemical weathering typically under tropical to subtropical climate conditions. The principal aluminium hydroxide minerals found in varying proportions with bauxites are gibbsite and the polymorphs boehmite and diaspore. Bauxites are typically classified according to their intended commercial application: abrasive, cem ...

Including:

• Bauxite - History
• Bauxite - World Bauxite Mine Production Reserves and Reserve Base

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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. Ore genesis - Internal processes. These processes are integral physical phenomena and chemical reactions internal to magmas, generally in plutonic or volcanic rocks. These include; Fractional crystallization, either creating monominerallic cumulate ores or contributing to the enrichment of ore mineral ...

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Ore genesis, Ore genesis - Ore genesis processes, Ore genesis - Internal processes, Ore genesis - Hydrothermal processes, Ore genesis - Metamorphic processes, Ore genesis - Surficial processes, Ore genesis - Classification of ore deposits, Ore genesis - Common classification groupings, Ore genesis - Genesis of common ores, Ore genesis - Iron, Ore genesis - Lead zinc silver, Ore genesis - Gold, Ore genesis - Platinum, Ore genesis - Nickel, Ore genesis - Copper, Ore genesis - Uranium, Ore genesis - Titanium, Ore genesis - Mineral sands, Ore genesis - Tin tungsten and molybdenum, Ore genesis - Rare earth elements niobium tantalum lithium, Ore genesis - Phosphate

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Bauxite was named after the village Les Baux de Provence in southern France, where it was first discovered in 1821 by the geologist Pierre Berthier. Knighted in 1832, Sir Berthier went on to establish the Berthier Museum of Geology in Tours. Due to the exhaustion of its bauxite mines, France has almost completely ceased the exploitation of bauxite since 1991. French mines were located in the Var, Bouches-du-Rhôn ...

See also:

Bauxite, Bauxite - History, Bauxite - World Bauxite Mine Production Reserves and Reserve Base

Read more here: » Bauxite: Encyclopedia II - Bauxite - History

Copper is found in association with many other metals and deposit styles. Commonly, copper is either formed within sedimentary rocks, or associated with igneous rocks. The world's major copper deposits are formed within the granitic porphyry copper style. The source of the copper is generally considered to be the lower crust or mantle where the granite melt forms. The copper is enriched by processes during crystallisation of the granite and forms as chalcopyrite — a sulfide mineral, ...

See also:

Ore genesis, Ore genesis - Ore genesis processes, Ore genesis - Internal processes, Ore genesis - Hydrothermal processes, Ore genesis - Metamorphic processes, Ore genesis - Surficial processes, Ore genesis - Classification of ore deposits, Ore genesis - Common classification groupings, Ore genesis - Genesis of common ores, Ore genesis - Iron, Ore genesis - Lead zinc silver, Ore genesis - Gold, Ore genesis - Platinum, Ore genesis - Nickel, Ore genesis - Copper, Ore genesis - Uranium, Ore genesis - Titanium, Ore genesis - Mineral sands, Ore genesis - Tin tungsten and molybdenum, Ore genesis - Rare earth elements niobium tantalum lithium, Ore genesis - Phosphate

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Uranium deposits are usually sourced from radioactive granites, where certain minerals such as monazite are leached during hydrothermal activity or during circulation of groundwater. 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. The majority of the world's nuclear power is ...

See also:

Ore genesis, Ore genesis - Ore genesis processes, Ore genesis - Internal processes, Ore genesis - Hydrothermal processes, Ore genesis - Metamorphic processes, Ore genesis - Surficial processes, Ore genesis - Classification of ore deposits, Ore genesis - Common classification groupings, Ore genesis - Genesis of common ores, Ore genesis - Iron, Ore genesis - Lead zinc silver, Ore genesis - Gold, Ore genesis - Platinum, Ore genesis - Nickel, Ore genesis - Copper, Ore genesis - Uranium, Ore genesis - Titanium, Ore genesis - Mineral sands, Ore genesis - Tin tungsten and molybdenum, Ore genesis - Rare earth elements niobium tantalum lithium, Ore genesis - Phosphate

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These three metals generally form in a certain type of granite, via a similar mechanism to intrusive-related gold and copper. 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 deposits form by reaction of mineralised fluids from the granite reacting with wall rocks such as limestone. Skarn mineralisation is also important in lead, zinc, copper, gold and occasionally uranium mineralisation. Greisen granite is ano ...

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Ore genesis, Ore genesis - Ore genesis processes, Ore genesis - Internal processes, Ore genesis - Hydrothermal processes, Ore genesis - Metamorphic processes, Ore genesis - Surficial processes, Ore genesis - Classification of ore deposits, Ore genesis - Common classification groupings, Ore genesis - Genesis of common ores, Ore genesis - Iron, Ore genesis - Lead zinc silver, Ore genesis - Gold, Ore genesis - Platinum, Ore genesis - Nickel, Ore genesis - Copper, Ore genesis - Uranium, Ore genesis - Titanium, Ore genesis - Mineral sands, Ore genesis - Tin tungsten and molybdenum, Ore genesis - Rare earth elements niobium tantalum lithium, Ore genesis - Phosphate

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Nickel deposits are generally found in two forms, either as sulfide or laterite. Sulfide type nickel deosits are formed in essentially the same manner as platinum deposits. 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 deposits. The best nickel deposits are formed where sulfide accumulates, much like in a placer gold deposit, in the base of lava tubes or volcanic ...

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Ore genesis, Ore genesis - Ore genesis processes, Ore genesis - Internal processes, Ore genesis - Hydrothermal processes, Ore genesis - Metamorphic processes, Ore genesis - Surficial processes, Ore genesis - Classification of ore deposits, Ore genesis - Common classification groupings, Ore genesis - Genesis of common ores, Ore genesis - Iron, Ore genesis - Lead zinc silver, Ore genesis - Gold, Ore genesis - Platinum, Ore genesis - Nickel, Ore genesis - Copper, Ore genesis - Uranium, Ore genesis - Titanium, Ore genesis - Mineral sands, Ore genesis - Tin tungsten and molybdenum, Ore genesis - Rare earth elements niobium tantalum lithium, Ore genesis - Phosphate

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The overwhelming majority of rare earth elements, tantalum and lithium are found within pegmatite. Ore genesis theories for these ores are wide and varied, but most involve metamorphism and igneous activity. Lithium is present as spodumene or lepidolite within pegmatite. Carbonatite intrusions are an important source of these elements. Ore minerals are essentially part of the unusual carbonatite mineralogy. ...

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Ore genesis, Ore genesis - Ore genesis processes, Ore genesis - Internal processes, Ore genesis - Hydrothermal processes, Ore genesis - Metamorphic processes, Ore genesis - Surficial processes, Ore genesis - Classification of ore deposits, Ore genesis - Common classification groupings, Ore genesis - Genesis of common ores, Ore genesis - Iron, Ore genesis - Lead zinc silver, Ore genesis - Gold, Ore genesis - Platinum, Ore genesis - Nickel, Ore genesis - Copper, Ore genesis - Uranium, Ore genesis - Titanium, Ore genesis - Mineral sands, Ore genesis - Tin tungsten and molybdenum, Ore genesis - Rare earth elements niobium tantalum lithium, Ore genesis - Phosphate

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Lead-zinc deposits are generally accompanied by silver, hosted within the lead sulfide galena or within the zinc sulfide sphalerite. 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 volcanic-hosted massive sulfide or VHMS) or in t ...

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Ore genesis, Ore genesis - Ore genesis processes, Ore genesis - Internal processes, Ore genesis - Hydrothermal processes, Ore genesis - Metamorphic processes, Ore genesis - Surficial processes, Ore genesis - Classification of ore deposits, Ore genesis - Common classification groupings, Ore genesis - Genesis of common ores, Ore genesis - Iron, Ore genesis - Lead zinc silver, Ore genesis - Gold, Ore genesis - Platinum, Ore genesis - Nickel, Ore genesis - Copper, Ore genesis - Uranium, Ore genesis - Titanium, Ore genesis - Mineral sands, Ore genesis - Tin tungsten and molybdenum, Ore genesis - Rare earth elements niobium tantalum lithium, Ore genesis - Phosphate

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Ore deposits are usually classified by ore formation processes and geological setting. 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. 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 ge ...

See also:

Ore genesis, Ore genesis - Ore genesis processes, Ore genesis - Internal processes, Ore genesis - Hydrothermal processes, Ore genesis - Metamorphic processes, Ore genesis - Surficial processes, Ore genesis - Classification of ore deposits, Ore genesis - Common classification groupings, Ore genesis - Genesis of common ores, Ore genesis - Iron, Ore genesis - Lead zinc silver, Ore genesis - Gold, Ore genesis - Platinum, Ore genesis - Nickel, Ore genesis - Copper, Ore genesis - Uranium, Ore genesis - Titanium, Ore genesis - Mineral sands, Ore genesis - Tin tungsten and molybdenum, Ore genesis - Rare earth elements niobium tantalum lithium, Ore genesis - Phosphate

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Iron ores are overwhelmingly derived from ancient sediments known as banded iron formations (BIFs). These sediments are composed of iron oxide minerals deposited on the sea floor. 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. Often, more recent weathering during the Tertiary or Eocene is required to convert the usual magnetite minerals into more easily processed hematite. Some iron deposits withi ...

See also:

Ore genesis, Ore genesis - Ore genesis processes, Ore genesis - Internal processes, Ore genesis - Hydrothermal processes, Ore genesis - Metamorphic processes, Ore genesis - Surficial processes, Ore genesis - Classification of ore deposits, Ore genesis - Common classification groupings, Ore genesis - Genesis of common ores, Ore genesis - Iron, Ore genesis - Lead zinc silver, Ore genesis - Gold, Ore genesis - Platinum, Ore genesis - Nickel, Ore genesis - Copper, Ore genesis - Uranium, Ore genesis - Titanium, Ore genesis - Mineral sands, Ore genesis - Tin tungsten and molybdenum, Ore genesis - Rare earth elements niobium tantalum lithium, Ore genesis - Phosphate

Read more here: » Ore genesis: Encyclopedia II - Ore genesis - Iron

Gold deposits are formed via a very wide variety of geological processes. Deposits are classified as primary, alluvial or placer deposits, or residual or laterite deposits. Often a deposit will contain a mixture of all three types of ore. Plate tectonics is the underlying mechanism for generating gold deposits. The majority of primary gold deposits fall into two main categories: lode gold dep ...

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Ore genesis, Ore genesis - Ore genesis processes, Ore genesis - Internal processes, Ore genesis - Hydrothermal processes, Ore genesis - Metamorphic processes, Ore genesis - Surficial processes, Ore genesis - Classification of ore deposits, Ore genesis - Common classification groupings, Ore genesis - Genesis of common ores, Ore genesis - Iron, Ore genesis - Lead zinc silver, Ore genesis - Gold, Ore genesis - Platinum, Ore genesis - Nickel, Ore genesis - Copper, Ore genesis - Uranium, Ore genesis - Titanium, Ore genesis - Mineral sands, Ore genesis - Tin tungsten and molybdenum, Ore genesis - Rare earth elements niobium tantalum lithium, Ore genesis - Phosphate

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Platinum and palladium are precious metals generally found in ultramafic rocks. 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. 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. Alternatively, platinum occurs in association with chromite either within the chromite mineral itsel ...

See also:

Ore genesis, Ore genesis - Ore genesis processes, Ore genesis - Internal processes, Ore genesis - Hydrothermal processes, Ore genesis - Metamorphic processes, Ore genesis - Surficial processes, Ore genesis - Classification of ore deposits, Ore genesis - Common classification groupings, Ore genesis - Genesis of common ores, Ore genesis - Iron, Ore genesis - Lead zinc silver, Ore genesis - Gold, Ore genesis - Platinum, Ore genesis - Nickel, Ore genesis - Copper, Ore genesis - Uranium, Ore genesis - Titanium, Ore genesis - Mineral sands, Ore genesis - Tin tungsten and molybdenum, Ore genesis - Rare earth elements niobium tantalum lithium, Ore genesis - Phosphate

Read more here: » Ore genesis: Encyclopedia II - Ore genesis - Platinum