|
Fenite
Fenite is a metasomatic alteration associated particularly with carbonatite intrusions and created, very rarely, by advanced carbon dioxide alteration (carbonation) of felsic and mafic rocks. It is characterised by the presence of alkali feldspar, sodic pyroxene and sodic amphibole. Fenite alteration is known, but restricted in distribution, around high-temperature metamorphic talc carbonates, generally in the form of an aureole around ultramafic rocks. Such examples include biotite-rich zones, amphibolite-calcite-scapolite alteration and other unusual skarn assemblages. The process is called fenitization. The type locality for fenite is the Fen Complex (Norwegian: Fensfeltet) in Nome, Telemark, Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t .... References External li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fenite (Late Devonian; Selsurt Mountain, Kola Peninsula, Russia) 1
Fenite is a metasomatic alteration associated particularly with carbonatite intrusions and created, very rarely, by advanced carbon dioxide alteration (carbonation) of felsic and mafic rocks. It is characterised by the presence of alkali feldspar, sodic pyroxene and sodic amphibole. Fenite alteration is known, but restricted in distribution, around high-temperature metamorphic talc carbonates, generally in the form of an aureole around ultramafic rocks. Such examples include biotite-rich zones, amphibolite- calcite-scapolite alteration and other unusual skarn assemblages. The process is called fenitization. The type locality for fenite is the Fen Complex (Norwegian: Fensfeltet) in Nome, Telemark, Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and the .... References Externa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbonatite
Carbonatite () is a type of intrusive rock, intrusive or extrusive rock, extrusive igneous rock defined by mineralogic composition consisting of greater than 50% carbonate minerals. Carbonatites may be confused with marble and may require geochemical verification. Carbonatites usually occur as small volcanic plug, plugs within zoned alkalic intrusive complexes, or as dike (geology), dikes, sill (geology), sills, breccias, and vein (geology), veins. They are almost exclusively associated with continental rift-related tectonic settings. It seems that there has been a steady increase in the carbonatitic igneous activity through the Earth's history, from the Archean Eon (geology), eon to the present. Nearly all carbonatite occurrences are intrusives or subvolcanic rock, subvolcanic intrusives. This is because carbonatite lava flows, being composed largely of soluble carbonates, are easily weathered and are therefore unlikely to be preserved in the geologic record. Carbonatite erupti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fen Complex
The Fen Complex ( no, Fensfeltet) in Nome, Telemark, Norway is a region noted for an unusual suite of igneous rocks. Several varieties of carbonatite are present in the area as well as lamprophyre, ijolite and other highly alkalic rocks. It is the type locality for fenite, a metasomatic rock commonly found around carbonatite and alkali intrusives.http://www.mindat.org/loc-14357.html Mindat location description The Fen Complex is a roughly circular area about three kilometres in diameter. It is located just west of the Oslo graben. Radiometric age dating on the carbonatites gave an age of 539 +/- 14 Myr. The host rocks for the intrusions are middle Proterozoic granites and gneiss and the complex was associated with the Cambrian rifting of the cratonic rocks.Faure, Gunter (2000) ''Origin of Igneous Rocks'', Springer, pp. 319-321 The complex is a protected location because of the rare minerals and rock types found there. The rocks were first described by Waldemar Christofer Brø ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Talc Carbonate
Talc carbonates are a suite of rock and mineral compositions found in metamorphosed ultramafic rocks. The term refers to the two most common end-member minerals found within ultramafic rocks which have undergone talc-carbonation or carbonation reactions: talc and the carbonate mineral magnesite. Talc carbonate mineral assemblages are controlled by temperature and pressure of metamorphism and the partial pressure of carbon dioxide within metamorphic fluids, as well as by the composition of the host rock. Compositional controls In a general sense, talc carbonate metamorphic assemblages are diagnostic of the magnesium content of the ultramafic protolith. * Lower-magnesian ultramafic rocks (12-18% MgO as a rule of thumb) tend to favor talc-chlorite assemblages * Medium-MgO rocks (15-25% MgO) tend to produce talc-amphibole assemblages. * High-MgO rocks with in excess of 25% MgO tend to form true talc-magnesite metamorphic assemblages. Thus, the MgO content of a metamorphosed ultram ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scapolite
The scapolites (Gr. σκάπος, rod, and λίθος, stone) are a group of rock-forming silicate minerals composed of aluminium, calcium, and sodium silicate with chlorine, carbonate and sulfate. The two endmembers are meionite () and marialite (). Silvialite is also a recognized member of the group. Properties The group is an isomorphous mixture of the meionite and marialite endmembers. The tetragonal crystals are hemihedral with parallel faces (like scheelite), and at times of considerable size. They are distinct and usually have the form of square columns, some cleavages parallel to the prism-faces. Crystals are usually white or greyish-white and opaque, though meionite is found as colorless glassy crystals in the ejected limestone blocks of Monte Somma, Vesuvius. The hardness is 5–6, and the specific gravity varies with the chemical composition between 2.7 (meionite) and 2.5 (marialite). The scapolites are especially liable to alteration by weathering processes, wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telemark
Telemark is a traditional region, a former county, and a current electoral district in southern Norway. In 2020, Telemark merged with the former county of Vestfold to form the county of Vestfold og Telemark. Telemark borders the traditional regions and former counties of Vestfold, Buskerud, Hordaland, Rogaland and Aust-Agder. The name ''Telemark'' means the "mark of the Thelir", the ancient North Germanic tribe that inhabited what is now known as Upper Telemark in the Migration Period and the Viking Age. In the Middle Ages, the agricultural society of Upper Telemark was considered the most violent region of Norway. Today, half of the buildings from medieval times in Norway are located here. The dialects spoken in Upper Telemark also retain more elements of Old Norse than those spoken elsewhere in the country. Upper Telemark is also known as the birthplace of skiing. The southern part of Telemark, Grenland, is more urban and influenced by trade with the Low Countries, no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nome, Norway
Nome is a municipality in Telemark in the county of Vestfold og Telemark in Norway. It is a part of the traditional region of Midt-Telemark and historically of Grenland region. The administrative centre of the municipality is the village of Ulefoss. The municipality of Nome was created on 1 January 1964 when the two former municipalities of Holla and Lunde were merged. Nome consists of a number of villages including Lunde, Ulefoss, Helgen, Flåbygd, and Svenseid. The area of the farmlands is 26.8 square kilometers (as of 2013); barley is farmed on 4.9 sq.kilometers. General information Name The municipality of Nome was created in 1964 and the name was taken from a lake in the river of '' Eidselva''. The meaning of the name is unknown (maybe related to the first element in the name Numedal). Coat-of-arms The coat-of-arms is from modern times. They were granted in 1989. The arms are silver and blue and are divided ''party per bend sinister'' to look like steps. It is me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type Locality (geology)
Type locality, also called type area, is the locality where a particular rock type, stratigraphic unit or mineral species is first identified. If the stratigraphic unit in a locality is layered, it is called a stratotype, whereas the standard of reference for unlayered rocks is the type locality. The term is similar to the term type site in archaeology or the term type specimen in biology. Examples of geological type localities Rocks and minerals * Aragonite: Molina de Aragón, Guadalajara, Spain * Autunite: Autun, France * Benmoreite: Ben More (Mull), Scotland * Blairmorite: Blairmore, Alberta, Canada * Boninite: Bonin Islands, Japan * Comendite: Comende, San Pietro Island, Sardinia * Cummingtonite: Cummington, Massachusetts * Dunite: Dun Mountain, New Zealand. * Essexite: Essex County, Massachusetts, US * Fayalite: Horta, Fayal Island, Azores, Portugal * Harzburgite: Bad Harzburg, Germany * Icelandite: Thingmuli (Þingmúli), Iceland * Ijolite: Iivaara, Kuusamo, Finl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skarn
Skarns or tactites are hard, coarse-grained metamorphic rocks that form by a process called metasomatism. Skarns tend to be rich in calcium-magnesium-iron-manganese-aluminium silicate minerals, which are also referred to as calc-silicate minerals.Ray, G.E., and Webster, I.C.L. (1991): An Overview of Skarn Deposits; in Ore Deposits, Tectonics and Metallogeny in the Canadian Cordillera; McMillan, W.J., compiler, B. C. Ministry of Energy, Mines and Petroleum Resources, Paper 1991-4, pages 213-252.Meinert, L.D., 1992. Skarns and Skarn Deposits; Geoscience Canada, Vol. 19, No. 4, p. 145-162.Hammarstrom, J.M., Kotlyar, B.B., Theodore, T.G., Elliott, J.E., John, D.A., Doebrich, J.L., Nash, J.T., Carlson, R.R., Lee, G.K., Livo, K.E., Klein, D.P., 1995. Cu, Au, and Zn-Pb Skarn Deposits, Chapter 12; United States Geological Survey: Preliminary Compilation of Descriptive Geoenvironmental Mineral Deposit Models: https://pubs.usgs.gov/of/1995/ofr-95-0831/CHAP12.pdf. These minerals form as a res ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphibolite
Amphibolite () is a metamorphic rock that contains amphibole, especially hornblende and actinolite, as well as plagioclase feldspar, but with little or no quartz. It is typically dark-colored and dense, with a weakly foliated or schistose (flaky) structure. The small flakes of black and white in the rock often give it a salt-and-pepper appearance. Amphibolite frequently forms by metamorphism of mafic igneous rocks, such as basalt. However, because metamorphism creates minerals entirely based upon the chemistry of the protolith, certain 'dirty marls' and volcanic sediments may also metamorphose to an amphibolite assemblage. Deposits containing dolomite and siderite also readily yield amphibolite (tremolite-schist, grunerite-schist, and others) especially where there has been a certain amount of contact metamorphism by adjacent granitic masses. Metamorphosed basalt (metabasalt) creates ''ortho-amphibolite'' and other chemically appropriate lithologies create ''para-amphibolite''. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcite
Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on Scratch hardness, scratch hardness comparison. Large calcite crystals are used in optical equipment, and limestone composed mostly of calcite has numerous uses. Other polymorphs of calcium carbonate are the minerals aragonite and vaterite. Aragonite will change to calcite over timescales of days or less at temperatures exceeding 300 °C, and vaterite is even less stable. Etymology Calcite is derived from the German ''Calcit'', a term from the 19th century that came from the Latin word for Lime (material), lime, ''calx'' (genitive calcis) with the suffix "-ite" used to name minerals. It is thus etymologically related to chalk. When applied by archaeology, archaeologists and stone trade pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 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] |
