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Skarn-type deposits are formed in a similar process to porphyry orebodies. Skarn deposits are developed due to replacement, alteration, and contact metasomatism of the surrounding country rocks by ore-bearing hydrothermal solution adjacent to a mafic, ultramafic, felsic, or granitic intrusive body.Skarn-type deposits are formed in a similar process to porphyry orebodies. Skarn deposits are developed due to replacement, alteration, and contact
Metasomatism – Wikipedia
of the surrounding country rocks by ore-bearing hydrothermal solution adjacent to a mafic, ultramafic, felsic, or granitic intrusive body.
What is skarn used for?
Skarn deposits are economically valuable as sources of metals such as tin, tungsten, manganese, copper, gold, zinc, lead, nickel, molybdenum and iron.
What minerals are in a skarn deposit?
Garnet and pyroxene are the dominant minerals in calcic exosk~s. Skarn deposits are also classified based on the dommant economic metal they contain; the principal types are iron, tungsten, copper, zinc-lead, and tin (Einaudi and Burt, 1982).
How skarn deposits are formed?
Skarn-type deposits are formed in a similar process to porphyry orebodies. Skarn deposits are developed due to replacement, alteration, and contact metasomatism of the surrounding country rocks by ore-bearing hydrothermal solution adjacent to a mafic, ultramafic, felsic, or granitic intrusive body.
What are marble rocks?
marble, granular limestone or dolomite (i.e., rock composed of calcium-magnesium carbonate) that has been recrystallized under the influence of heat, pressure, and aqueous solutions. Commercially, it includes all decorative calcium-rich rocks that can be polished, as well as certain serpentines (verd antiques).
What is shale rock?
Shale, any of a group of fine-grained, laminated sedimentary rocks consisting of silt- and clay-sized particles. Shale is the most abundant of the sedimentary rocks, accounting for roughly 70 percent of this rock type in the crust of the Earth. Shales are often found with layers of sandstone or limestone.
What is garnet schist?
Garnet schist (5.5 cm across) has conspicuous, large or small garnet crystals. Garnets in schists are typically very deep red-colored. The surrounding matrix is often a grayish and mica-rich. The garnet-muscovite schist shown above is early Late Cretaceous in age (89 to 92 million years).
What does schist look like?
Schist (/ʃɪst/ shist) 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 or plates.
What kind of rock can be a Protolith?
The original rock that has undergone metamorphism is called the protolith. Protolith can be any type of rock and sometimes the changes in texture and mineralogy are so dramatic that is difficult to distinguish what the protolith was. Note that diagenesis and weathering are also a changes in form that occur in rocks.
What is skarn made up of?
The minerals commonly present in a skarn include iron oxides, calc-silicates (wollastonite, diopside, forsterite), andradite and grossularite garnet, epidote, and calcite. Many skarns also include ore minerals; several productive deposits of copper or other base metals have been found in and adjacent to skarns.
What is skarn metamorphism?
Skarn is a metamorphic rock that has been chemically and mineralogically altered by metasomatism. Metasomatism is the alteration of rocks by hot, chemically-active fluids that flow or diffuse through the rocks and cause recrystallization and compositional change.
How do you identify Hornfels?
Under a microscope the structure of hornfels is very distinctive, with small, generally equigranular, mineral grains fitting closely together like the fragments of a mosaic or a rough pavement. Texture – granular, platy or elongate crystals randomly oriented so no foliation evident.
What is amphibolite rock?
Amphibolite, a rock composed largely or dominantly of minerals of the amphibole group. The term has been applied to rocks of either igneous or metamorphic origin. In igneous rocks, the term hornblendite is more common and restrictive; hornblende is the most common amphibole and is typical of such rocks.
Is coal a mineral?
Coal is very different from mineral rocks, which are made of inorganic material. Coal is made of fragile plant matter, and undergoes many changes before it becomes the familiar black and shiny substance burned as fuel.
What is Hornfels rock?
Hornfels is medium-to-coarse crystalline metamorphic rocks formed out of contact metamorphism, dark color, and rich in silicates with granoblastic and porphyroblastic texture.
How is scheelite formed?
Scheelite is formed by contact metamorphic skarn type environment, in high-temperature hydrothermal veins, and less commonly in granite and pegmatite rocks.
Is platinum found in skarn deposits?
The occurrence of platinum group elements is reported in some skarns (e.g. Knopf, 1942). These deposits have not been well documented in the literature and most appear to represent metasomatism of ultramafic rocks (e.g. Yu, 1985).
What is the color of skarn?
Genetically, skarnoid is intermediate between a purely metamorphic hornfels and a purely metasomatic, coarse-grained skarn. Due to typical compositions of sedimentary protoliths it generally is pale in color and Fe poor in composition.
Is schist a bad word?
Schist. Nope, not a curse word. It’s actually a common type of metamorphic rock that can be split easily into sheets.
What causes Metasomatism?
In the metamorphic environment, metasomatism is created by mass transfer from a volume of metamorphic rock at higher stress and temperature into a zone with lower stress and temperature, with metamorphic hydrothermal solutions acting as a solvent.
Is Mica rock worth anything?
Sheet mica prices vary with grade and can range from less than $1 per kilogram for low-quality mica to more than $2,000 per kilogram for the highest quality.
What are epithermal deposits?
➢ Epithermal Gold refers to a type of gold deposit formed from hydrothermal fluids. at shallow levels in the earth’s crust. “Epithermal” is an old term used to classify. hydrothermal deposits based on temperature and depth of deposition.
Are schist rocks worth anything?
Schist may be worth mining if it contains useful minerals in large concentration. Common minerals extracted from schistose metamorphic rocks are garnet, kyanite, talc and graphite. A heap of quartz schist slabs demonstrating platy habit which is caused by the abundance of platy minerals.
What rock contains pyroxene?
Minerals in the pyroxene group are abundant in both igneous and metamorphic rocks. Their susceptibility to both chemical and mechanical weathering makes them a rare constituent of sedimentary rocks. Pyroxenes are classified as ferromagnesian minerals in allusion to their high content of magnesium and iron.
