Ore mineralization is the process of formation of minerals in ore deposits role in a rock. In the formation of these minerals are also associated with other minerals minerals. Formation of these minerals show credentials such as shape, appearance parts, twinning and others. Some minerals form a well-developed crystals (euhedral) pyrite, hematite, wolframite, arsenopyrite, cobalt, magnetite. Standard forms crystals in mineralogy: Cubic, octahedral, tabular, accicular, columnar, bladed, fibrous, colloform, micaceous, prismatic
The crust consists of rocks-igneous, sedimentary, and metamorphic. Understanding is the deposits of mineral ore that can be extracted (taken) economically valuable minerals, and ore in a deposit is dependent on two main factors, namely the level of concentrated (precious metal content in the sediment), the location and size (dimensions) precipitate. To achieve the levels of economic, minerals ore or valuable mineral components are naturally concentrated in the crust until a certain minimum level depends on the type of ore or mineral.
The Process Of Formation Of Mineral Deposits Of Primary
The primary ore mineral formation can be broadly classified into five types of deposits, namely:
A . Magmatic Liquid Phase
Magmatic Liquid phase is a phase of formation of minerals, where minerals are formed directly on the magma (magma differentiation), for example by means of gravitational settling. Many minerals formed in this way is chromite, titamagnetit, and petlandit. Magmatic liquid phase can be divided into:
- Components of rocks, minerals that are formed will be spread evenly throughout the rock. Examples of diamonds and platinum.
- Segregation, a mineral that is formed is not spread evenly, but only less concentrated in the rocks.
Injection, a mineral that forms no longer located in the magma (igneous rocks), but has been pushed out of the magma.
Pegmatites is igneous rock formed from magma injection. As a result of magmatic crystallization at the beginning and the pressure around the magma, the residual liquid is injected and the mobile will break through the surrounding rock as a dyke, sill, and stockwork.
Crystals from pegmatites be large, due to the absence of pressure and temperature contrast between magma with rocks around it, so that freezing was slow. Pegmatites minerals include: light metals (Li-silicate, Be-silicate (Beal-silicates), Al-rich silicate), heavy metals (Sn, Au, W, and Mo), rare elements (Niobium, Iodine (Y), Ce, Zr, La, Tantalum, Th, U, Ti), gems (ruby, sapphire, beryl, topaz, rose tourmaline, rose quartz, smoky quartz, rock crystal).
C. Phase Pneumatolitik
Pneumatolitik is the process of chemical reactions of gases and liquids of the magma in an environment close to the magma. From this point of geology, this is called contact-metamorphism, because of the symptoms of contact between older rocks by younger magma. Mineral contact can occur when the hot steam with high temperature of the magma in contact with a reactive wall rocks. Contact minerals formed include: wolastonit (CaSiO3), amphibol, quartz, epidote, garnet, vesuvianit, tremolit, topaz, aktinolit, tourmaline, diopsit, and skarn. Symptoms of contact metamorphism appears with the change at the edges of igneous intrusions and especially in the intruded rocks, namely: baking (roasting) and hardening (hardening).
Igneous metamorfism is any kind of alteration (alteration) associated with igneous breakthrough. Rocks are intruded by the rock in general will was recrystallized, modified (Altered), and replaced (replaced). These changes are caused by heat and fluids are dispersed or activated by the breakthrough earlier. Therefore, these deposits belong to the contact metamorphism.
Pneomatolitis process is more emphasized the role of the temperature of the water vapor activity. Pirometamorfisme emphasize only the effect of temperature on the reaction while pirometasomatisme replacement (replacement), and contact metamorphism at about the contact. Location of the process is generally in the depths of the earth, the environmental pressures and high temperatures.
Ore minerals in the sediment contact metasomatisme generally simple sulfides and oxides such as spalerit, galena, chalcopyrite, bornite, and some molybdenite. Few deposits of this type is really the absence of iron, will generally contain a lot of pyrite or magnetite and hematite. Scheelit also found in deposits of this type
D. Hydrothermal Phase
Is the residual magma hydrothermal solution that is "aqueous" as a result of magma differentiation. Is rich hydrothermal metals are relatively mild, and is the largest source (90%) of the process of forming a precipitate. Based on how the formation of deposits, recognized two types of hydrothermal deposits, namely:
- Cavity filing, filling the holes that already exist in the rocks.
- Metasomatisme, replacing the elements that already exist in rocks with new elements from hydrothermal solutions.
Paragenesis and mineral deposits hipothermal gangue are: gold (Au), magnetite (Fe3O4), hematite (Fe2O3), chalcopyrite (CuFeS2), arsenopyrite (FeAsS), pirrotit (FeS), galena (PbS), pentlandite (NIS), wolframit: Fe (Mn) WO4, Scheelit (CaWO4), kasiterit (SnO2), Mo-sulphide (MoS2), Ni-Co sulfide, nikkelit (Nias), spalerit (ZnS), with gangue minerals include: topaz, feldspar-feldspar, quartz, tourmalin, silicates, carbonates
While the mesothermal deposits paragenesis and gangue minerals are: stanite (Sn, Cu) sulfide, sulfides: spalerit, enargit (Cu3AsS4), Cu sulfide, Sb sulfides, stibnit (Sb2S3), tetrahedrit (Cu, Fe) 12Sb4S13, bornite (Cu2S ), galena (PbS) and chalcopyrite (CuFeS2), with minerals gangue: kabonat-carbonate, quartz, and pyrite.
Paragenesis and mineral deposits ephitermal ganguenya are: native copper (Cu), argentite (AGS), type Ag-Pb sulfide complexes, markasit (FeS2), pyrite (FeS2), cinabar (HgS), realgar (ASS), antimonit (Sb2S3) , stannit (CuFeSn), with minerals gangue: Chalcedon (SiO2), Mg carbonates, rhodokrosit (MnCO3), barite (BaSO4), zeolite (Al-silicate).
E. Volcanic Phase
Volcanic sediment phase is the end product of the primary ore formation processes. As a result of volcanic activity phases are:
- Lava flow
- Exhalation
- Geyser
If viewed in terms of economic, economical deposition of the volcanic phase are: sulfur (sulfur crystals and mud sulfur), iron oxides (eg hematite, Fe2O3). Volkanogenik massive sulphide associated with submarine volcanism, for example, deposits of copper-lead-zinc Kuroko in Japan, and most base metals deposits in Canada.
The Process Of Formation Of Sedimentary Deposits
Sedimentary ore mineral is a mineral ore in connection with sedimentary rock, formed by the influence of water, life, the air during the sedimentation, or formed by weathering or hydrothermal processes. Sedimentary ore minerals generally follow the layer (stratiform) or adjacent to a particular lithology (stratabound).
Y. B. Chaussier (1979), divides the formation of sedimentary minerals by source metal and based on its host rock. Based on the source of metal divided into two supergene deposits of metal deposition from the proceeds of rock or ore rombakan primary), as well as hipogen sediment (sediment metal derived from the magma activity / epithermal). While based on host-rock (with the deposition of sedimentary rocks) into two parts, namely singenetik deposits (deposits that formed simultaneously with the formation of rocks) as well as epigenetic deposits (mineral deposits formed after the rocks there).
Y. B. Chaussier (1979), divides the formation of sedimentary minerals by source metal and based on its host rock. Based on the source of metal divided into two supergene deposits of metal deposition from the proceeds of rock or ore rombakan primary), as well as hipogen sediment (sediment metal derived from the magma activity / epithermal). While based on host-rock (with the deposition of sedimentary rocks) into two parts, namely singenetik deposits (deposits that formed simultaneously with the formation of rocks) as well as epigenetic deposits (mineral deposits formed after the rocks there).
The occurrence of secondary mineral deposits or deposits influenced four factors: the source of the minerals, metals or metalloids, supergene or hypogene (primary or secondary), the erosion of the mineralized area which is then deposited in the basin (supergene), from biochemistry due to bacteria, organisms such as sediment diatomae , coal, and petroleum, as well as from the magma in the crust or volcanism (hypogene).
1. Ore Minerals Formed by The Chemical Processes Of Change And As a Result Of Surface Weathering And Transport
Normally the material earth can not sustain its existence and will have geochemical transport is distributed back and mixed with other materials. The process by which elements move to the location of the new geochemical and environmental geochemistry called dispersion. In contrast to mechanical dispersion, the dispersion of chemical chemically get to know the cause of a dispersion.
In this case the geochemical dispersion of primary and secondary geochemical dispersion. Primary geochemical dispersion is the dispersion of chemicals that occur in the crust of the earth, including the placement of the elements during the formation of ore deposits, regardless of how the ore body formed. Secondary geochemical dispersion is the dispersion of chemical that occurs in the earth's surface, including the re-distribution of primary dispersion patterns by a process that usually occurs on the surface, among others, the process of weathering, transport, and deposition. Material transported to the sedimentation process can be either particles or ions, and finally deposited in a place. Greatly affect the mobility element of the dispersion. Elements with low mobility tend to be close to the ore body, while the elements with high mobility tend to be relatively far from the ore body. It also depends on the chemical nature of Eh and pH environments such as Cu in an acidic condition would have high mobility whereas in alkaline conditions will have low mobility.
As an example can be given to the process of secondary enrichment in the sediment lateritik. Weathering resulting from the oxidation reaction with oxygen from the air source or water surface. Oxidation runs downward to the extent of ground water. As a result of this oxidation process, several specific minerals dissolve and are carried seep under the surface of the ground, then deposited (in the reduction zone). The surface is not soluble, will be hollow, reddish yellow, and often referred to as gossan. Examples of these deposits is laterite nickel deposits.
2 Mineral Deposits Formed by Mechanical Weathering
Here Minerals formed by mechanical concentration of mineral ores and solution of the residue. Sorting process which involves the deposition of hanging by the grain size and weight of the type referred to as sediment placer. Minerals are important placer Pt, Au, kasiterit, magnetite, monazite, ilmenite, zircon, diamond, garnet, tantalum, rutile, etc
Based on the place where deposited, put placer or minerals can be divided into:
- The precipitate placer eluvium, found near or around the primary ore mineral resources. They are formed from only a few trips residue (scratches), were weathered material after washing. As an example of the platinum deposits in the Urals.
- Placer alluvium, it is important placer sediment. Formed by the continuous moving river water, because the separation of specific gravity, the heavy mineral ore will move down the river. The intensity of enrichment would be obtained if the flow rate decreases, as beside the meanders, the river estuary and so on. Examples of these types of deposits are Au-placer in California.
- Placer ocean / beach, the precipitate is formed by the waves hitting the beach due to the activity and washed sand beach. Minerals are common here are ilmenite, magnetite, monazite, rutile, zircon, and diamond
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Fossil placer, an ancient primary sediment that has become fossilized and sometimes as metamorphic. As an example of this is the Proterozoic sediments Witwatersand, South Africa, is the world's largest gold region, production is more third world. Gold and uranium occur in some layers of conglomerate. Mineralization spread along 250 km. Deepest mines in the world up to 3000 meters, was made possible because there geotermis
a. Environmental Land
Clastic rocks that formed in dry climates are characterized by a red color due to oxidation of Fe in the literature and is commonly called "red beds". If the concentration of metallic elements near the surface of the ground or below ground where high precipitation allows concentration of the solution occurs and experienced metal leaching (leaching) soak the soil with water and then fill in between the grains of clastic sediments. Colloids ore would rather place by cation exchange between Fe and clay minerals or clay minerals due to absorption by itself.
b. Marine Environment
Genesis of mineral deposits in the marine environment is very different from terrestrial environments generally have a water supply with high levels of elements in the ocean compared to the womb. Content of sea water has a low element. For example, sea water levels for Fe 2 x 10-7% concentration of minerals that make up the precious metal this can happen if you have special circumstances (especially Fe and Mn) as:
a. The existence of one source of metals derived from weathering of rocks on land or under sea hydrothermal systems.b. Transport in solution, possibly as colloids. Iron is the dominant metal and carried along as Fe (OH) soil particles.
c. Sediment in sedimentary deposits, as Fe (OH) 3, or Fe-silicate FeCO3 dependent differences in reduction potential (Eh).
Ore in the marine environment can be olit, colloidal solution formed by wrapping another material such as sand or fossil fragments. Symmetrical form of skin caused by changes in the composition (Fe, Al, SiO2). With continuing growth, olit will be stable on the seabed which is embedded in the material containing clay Carbonat some good iron. On the seabed may olit is reworked. With the state of the iron ore and manganese as an example of ferro manganese nodules that now cover the vast area of ocean.
Ore mineralization is the process of formation of minerals in ore deposits role in a rock. In the formation of these minerals are also associated with other minerals minerals. Formation of these minerals show credentials such as shape, appearance parts, twinning and others. Some minerals form a well-developed crystals (euhedral) pyrite, hematite, wolframite, arsenopyrite, cobalt, magnetite. Standard forms crystals in mineralogy: Cubic, octahedral, tabular, accicular, columnar, bladed, fibrous, colloform, micaceous, prismatic
Minerals In The Rock Formation In 3 Parts Formers:
- Igneous rock-forming minerals: Composed of primary minerals such as quartz, plagioclase, biotite,orthoclase, muscovite, amfibol, pyroxene, and olivine. And there are also secondary minerals derived from analteration of primary minerals such as chlorite, sericite, kaolinite, calcite and serpentinite. But sometimes there are additional minerals that appear in these rocks such as corundum, hematite, apatite, and limonite.
- Mineral formation consists of sedimentary rocks: Calcite, dolomite is the main mineral of limestone. However, clay minerals such as kaolinite clays, monmorilonit, haloysit, anhydrite, illite, and gypsum are often also seen as the rock itself.
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