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Peñasquito Mine
The Peñasquito Polymetallic Mine is the fifth largest silver mine in the world and the second largest in Mexico. It is located in north-eastern corner of the State of Zacatecas and is wholly owned by Newmont Goldcorp. It is an open pit operation which began operations in March 2010, but still managed to produce 13,952,600 ounces of silver that year. Estimated reserves for the Peñasquito Mine are 17.82 million oz of gold, 1,070.1 million oz of silver, 3,214 tons of lead and 7,098 million tons of zinc. The mine has its own radio station, XHESP-FM 98.9 "Radio Peñasco". Geology The country rock consists of Mesozoic sediments that were deposited in the Basin of Mexico (Mexico Geosyncline). These sediments were intruded by quartz-feldspar porphyries, quartz monzonite porphyries, and other feldspar-phyric intrusives in the late Eocene to the mid- Oligocene, which form sills, dikes, and stocks. The primary ore for the Peñasquito Polymetallic Mine is in two diatreme breccias, named t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zacatecas
, image_map = Zacatecas in Mexico (location map scheme).svg , map_caption = State of Zacatecas within Mexico , coordinates = , coor_pinpoint = , coordinates_footnotes = , subdivision_type = Country , subdivision_name = Mexico , subdivision_type1 = Capital , subdivision_name1 = Zacatecas , subdivision_type2 = Municipalities , subdivision_name2 = 58 , established_title = Admission , established_date = December 23, 1823 , established_title2 = Order , established_date2 = 10th , founder = , seat_type = , seat = , government_footnotes = , leader_party = , leader_title = Governor , leader_name = David Monreal Ávila , leader_title1 = Senators , leader_name1 = , leader_title2 = Deputies , leader_name2 = , unit_pref ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diatreme
A diatreme, sometimes known as a maar-diatreme volcano, is a volcanic pipe formed by a gaseous explosion. When magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ... rises up through a crack in Earth's crust and makes contact with a shallow body of groundwater, rapid expansion of heated water vapor and volcanic gases can cause a series of explosions. A relatively shallow crater (known as a ''maar'') is left, and a rock-filled fracture (the actual diatreme) in the crust. Diatremes breach the surface and produce a steep, inverted cone shape. The term ''diatreme'' has been applied more generally to any concave body of broken rock formed by explosive or hydrostatics, hydrostatic forces, whether or not it is related to volcanism. The word comes . Global distribution Maar-diatreme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. About 20% to 25% of sedimentary rock is carbonate rock, and most of this is limestone. The remaining carbonate rock is mostly dolomite, a closely related rock, which contains a high percentage of the mineral dolomite, . ''Magnesian limestone'' is an obsolete and poorly-defined term used variously for dolomite, for limes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrothermal Alteration
Metasomatism (from the Greek μετά ''metá'' "change" and σῶμα ''sôma'' "body") is the chemical alteration of a rock by hydrothermal and other fluids. It is the replacement of one rock by another of different mineralogical and chemical composition. The minerals which compose the rocks are dissolved and new mineral formations are deposited in their place. Dissolution and deposition occur simultaneously and the rock remains solid. Synonyms to the word metasomatism are metasomatose and metasomatic process. The word metasomatose can also be used as a name for specific varieties of metasomatism (for example '' Mg-metasomatose'' and '' Na-metasomatose''). Metasomatism can occur via the action of hydrothermal fluids from an igneous or metamorphic source. In the igneous environment, metasomatism creates skarns, greisen, and may affect hornfels in the contact metamorphic aureole adjacent to an intrusive rock mass. In the metamorphic environment, metasomatism is created by mass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epidote
Epidote is a calcium aluminium iron sorosilicate mineral. Description Well developed crystals of epidote, Ca2Al2(Fe3+;Al)(SiO4)(Si2O7)O(OH), crystallizing in the monoclinic system, are of frequent occurrence: they are commonly prismatic in habit, the direction of elongation being perpendicular to the single plane of symmetry. The faces are often deeply striated and crystals are often twinned. Many of the characters of the mineral vary with the amount of iron present for instance, the color, the optical constants, and the specific gravity. The color is green, grey, brown or nearly black, but usually a characteristic shade of yellowish-green or pistachio-green. It displays strong pleochroism, the pleochroic colors being usually green, yellow and brown. Clinozoisite is green, white or pale rose-red group species containing very little iron, thus having the same chemical composition as the orthorhombic mineral zoisite. The name, due to Haüy, is derived from the Greek word "epidos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorite Group
The chlorites are the group of phyllosilicate minerals common in low-grade metamorphic rocks and in altered igneous rocks. Greenschist, formed by metamorphism of basalt or other low-silica volcanic rock, typically contains significant amounts of chlorite. Chlorite minerals show a wide variety of compositions, in which magnesium, iron, aluminium, and silicon substitute for each other in the crystal structure. A complete solid solution series exists between the two most common end members, magnesium-rich clinochlore and iron-rich chamosite. In addition, manganese, zinc, lithium, and calcium species are known. The great range in composition results in considerable variation in physical, optical, and X-ray properties. Similarly, the range of chemical composition allows chlorite group minerals to exist over a wide range of temperature and pressure conditions. For this reason chlorite minerals are ubiquitous minerals within low and medium temperature metamorphic rocks, some igneous r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propylitic Alteration
Propylitic alteration is the chemical alteration of a rock, caused by iron and magnesium bearing hydrothermal fluids, altering biotite or amphibole within the rock groundmass. It typically results in epidote–chlorite–albite alteration and veining or fracture filling with the mineral assemblage along with pyrite. The alteration occurs due to hot fluids that have a high sodium ion composition. This is typically due to fluids that have lost potassium ions in potassic alteration and gained sodium ions. See also * Metasomatism Metasomatism (from the Greek μετά ''metá'' "change" and σῶμα ''sôma'' "body") is the chemical alteration of a rock by hydrothermal and other fluids. It is the replacement of one rock by another of different mineralogical and chemical com ... References * {{Citation , publisher = Springer , isbn = 978-3-642-01782-7 , last = Taylor , first = Roger , title = Ore Textures: Recognition and Interpretation , year = 2009 , page = 58 Geologica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO2. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar. Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation from α-quartz to β-quartz takes place abruptly at . Since the transformation is accompanied by a significant change in volume, it can easily induce microfracturing of ceramics or rocks passing through this temperature threshold. There are many different varieties of quartz, several of which are classified as gemstones. Since antiquity, varieties of quartz have been the most commonly used minerals in the making of jewelry and hardstone carvings, especially in Eurasia. Quartz is the mineral defining the val ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrite
The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Iron, FeSulfur, S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic Luster (mineralogy), luster and pale brass-yellow hue give it a superficial resemblance to gold, hence the well-known nickname of ''fool's gold''. The color has also led to the nicknames ''brass'', ''brazzle'', and ''Brazil'', primarily used to refer to pyrite found in coal. The name ''pyrite'' is derived from the Greek language, Greek (), 'stone or mineral which strikes fire', in turn from (), 'fire'. In ancient Roman times, this name was applied to several types of stone that would create sparks when struck against steel; Pliny the Elder described one of them as being brassy, almost certainly a reference to what we now call pyrite. By Georgius Agricola's time, , the term had become a generic term for all of the pyrite group, sulfide minerals. Pyrite is usua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sericite
Sericite is the name given to very fine, ragged grains and aggregates of white (colourless) micas, typically made of muscovite, illite, or paragonite. Sericite is produced by the alteration of orthoclase or plagioclase feldspars in areas that have been subjected to hydrothermal alteration typically associated with copper, tin, or other hydrothermal ore deposits. Sericite also occurs as the fine mica that gives the sheen to phyllite and schistose metamorphic rocks. The name comes from Latin ''sericus'', meaning "silken" in reference to the location from which silk was first utilized, which in turn refers to the silky sheen of rocks with abundant sericite. File:Granite pmg ss 2006.jpg, Granite in thin section under cross-polarized light in which feldspar crystals exhibit sericite alteration. File:Staurolite garnet schist 3mm xp 2007.jpg, Staurolite-garnet schist in thin section under cross-polarized light with sericite. References External linksMindat [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phyllic Alteration
Phyllic alteration is a hydrothermal alteration zone in a permeable rock that has been affected by circulation of hydrothermal fluids. It is commonly seen in copper porphyry ore deposits in calc-alkaline rocks. Phyllic alteration is characterised by the assemblage of quartz + sericite + pyrite, and occurs at high temperatures and moderately acidic (low pH) conditions. Hydrogen-ion metasomatism is the process that causes phyllic alteration. While the mineralogy of the rock is altered throughout, texture is preserved and primary porphyry structure (including position of original veins) may still be visible. If a rock undergoes phyllic alteration, then orthoclase feldspar, biotite and various silicates are altered in addition to plagioclase. Plagioclase will be altered to sericite (a fine-grained white mica) by sericitic alteration, and mafic minerals are replaced by quartz. Tourmaline may appear as radiating aggregate or prismatic crystals between the quartz-sericite assemblage ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfosalt
Sulfosalt minerals are sulfide minerals with the general formula , where *A represents a metal such as copper, lead, silver, iron, and rarely mercury, zinc, vanadium *B usually represents semi-metal such as arsenic, antimony, bismuth, and rarely germanium, or metals like tin and rarely vanadium *X is sulfur or rarely selenium and/or tellurium. The Strunz classification includes the sulfosalts in a ''sulfides and sulfosalts'' superclass. A group which have similar appearing formulas are the sulfarsenides (for example cobaltite (Co,Fe)AsS). In sulfarsenides the arsenic substitutes for sulfide anions whereas in the sulfosalts the arsenic substitutes for a metal cation.Klein, Cornelis and Cornelius S. Hurlbut (1985). ''Manual of Mineralogy'', 20th ed., John Wiley and Sons, New York . About 200 sulfosalt minerals are known. Examples include: File:Proustite (long prismatic crystal) - Chanarcillo, Copiapo Province, Atacama Region, Chile.jpg, As illustrated by this specimen of proustite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
