Tuff (from the Italian "tufo") is a type of rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption. Italian ( or lingua italiana) is a Romance language spoken by about 63 million people as a First language, primarily in Italy. In Geology, rock is a naturally occurring aggregate of Minerals and/or Mineraloids The Earth's outer solid layer the ‘ Lithosphere Volcanic ash consists of small Tephra, which are bits of pulverized rock and glass created by volcanic eruptions less than in diameter (Note that tuff is a type of rock entirely different from tufa. Tufa article--> Tufa is the name for an unusual geological )
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Volcanic ash
The products of a volcanic eruption are volcanic gases, lava, steam, and tephra. Plate tectonics and hotspots Divergent plate boundaries At the Lava is molten rock expelled by a Volcano during an eruption When first expelled from a volcanic vent it is a Liquid at Temperatures Uses A Steam engine uses the expansion of steam in order to drive a Piston or Turbine to perform Mechanical work. Tephra is air-fall material produced by a volcanic eruption regardless of composition or fragment size Magma is blown apart when it interacts violently with volcanic gases and steam. Solid material produced and thrown into the air by such volcanic eruptions is called tephra, regardless of composition or fragment size. Tephra is air-fall material produced by a volcanic eruption regardless of composition or fragment size If the resulting pieces of ejecta are small enough, the material is called volcanic ash, defined as such particles less than 2 mm in diameter, sand-sized or smaller. Sand is a naturally occurring Granular material composed of finely divided rock and Mineral particles These particles are small, slaggy pieces of magma and rock that have been tossed into the air by outbursts of steam and other gases; magma may have been torn apart as it became vesicular by the expansion of the gases within it. Slag is the By-product of Smelting Ore to purify Metals They can be considered to be a mixture of metal Oxides however Magma (Plurals magmas and magmata) is molten rock that sometimes forms beneath the surface of the Earth (or any other Terrestrial planet Vesicular texture is a Volcanic rock texture characterised by or containing many vesicles
Breccias
Among the loose beds of ash that cover the slopes of many volcanoes, three classes of materials are represented. Plate tectonics and hotspots Divergent plate boundaries At the In addition to true ashes of the kind described above, there are lumps of the old lavas and tuffs forming the walls of the crater, etc. , which have been torn away by the violent outbursts of steam, and pieces of sedimentary rocks from the deeper parts of the volcano that were dislodged by the rising lava and are often intensely baked and recrystallized by the heat to which they have been subjected. Sedimentary rock is one of the three main rock types (the others being igneous and Metamorphic rock) Recrystallization (see also Crystallization) is a physical process that has meanings in Chemistry, Metallurgy and Geology.
In some great volcanic explosions nothing but materials of the second kind were emitted, as at Mount Bandaisan in Japan in 1888. For a topic outline on this subject see List of basic Japan topics. Year 1888 ( MDCCCLXXXVIII) was a Leap year starting on Sunday (click on link for calendar of the Gregorian calendar (or a There have been many eruptions also in which the quantity of broken sedimentary rocks that mingled with the ash is very great; as instances we may cite the volcanoes of the Eifel and the Devonian tuffs, known as "Schalsteins," in Germany. The Eifel is a low mountain range in western Germany. It occupies parts of southwestern North Rhine-Westphalia and northwestern Rhineland-Palatinate The Devonian is a geologic period and system of the Paleozoic era spanning from to million years ago. Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. In the Scottish coalfields some old volcanoes are plugged with masses consisting entirely of sedimentary debris: in such a case we must suppose that no lava was ejected, but the cause of the eruption was the sudden liberation and expansion of a large quantity of steam. Scotland ( Gaelic: Alba) is a Country in northwest Europethat occupies the northern third of the island of Great Britain. These accessory or adventitious materials, however, as distinguished from the true ashes, tend to occur in angular fragments; and when they form a large part of the mass the rock is more properly a "volcanic breccia" than a tuff. Breccia (ˈbrɛtʃiə ˈbrɛʃiə breach is a rock composed of angular fragments of several Minerals or rocks in a matrix, that is a cementing material The ashes vary in size from large blocks twenty feet or more in diameter to the minutest impalpable dust. The large masses are called "volcanic bombs"; they have mostly a rounded, elliptical or pear-shaped form owing to rotation in the air while they were still viscous. A volcanic bomb is a globe of molten rock ( Tephra) larger than 65 mm (2 Many of them have ribbed or nodular surfaces, and sometimes they have a crust intersected by many cracks like the surface of a loaf of bread. Any ash in which they are very abundant is called an agglomerate. Agglomerates (from the Latin 'agglomerare' meaning 'to form into a ball' are coarse accumulations of large blocks of volcanic material that contain at least
In those layers and beds of tuff that have been spread out over considerable tracts of country and which are most frequently encountered among the sedimentary rocks, smaller fragments preponderate greatly and bombs more than a few inches in diameter may be absent altogether. A tuff of recent origin is generally loose and incoherent, but the older tuffs have been, in most cases, cemented together by pressure and the action of infiltrating water, making rocks which, while not very hard, are strong enough to be extensively used for building purposes (e. g. in the neighborhood of Rome). Rome ( Roma ˈroma Roma is the capital city of Italy and Lazio, and is Italy's largest and most populous city with more than 2 If they have accumulated subaerially, like the ash beds found on Mt. Etna or Vesuvius at the present day, tuffs consist almost wholly of volcanic materials of different degrees of fineness with pieces of wood and vegetable matter, land shells, etc. The term subaerial, mainly used in Geology, describes events or structures located at the Earth 's surface "under the air" Mount Vesuvius (in Italian Monte Vesuvio and in Latin Mons Vesuvius) is an active Stratovolcano east of Naples But many volcanoes stand near the sea, and the ashes cast out by them are mingled with the sediments that are gathering at the bottom of the waters. In this way ashy muds or sands or even in some cases ashy limestones are being formed. In computer gaming, a MUD ( Multi-User Dungeon, Domain or Dimension) is a multi-player computer game that combines elements of Sand is a naturally occurring Granular material composed of finely divided rock and Mineral particles Limestone is a Sedimentary rock composed largely of the Mineral Calcite ( Calcium carbonate: CaCO3 As a matter of fact most of the tuffs found in the older formations contain admixtures of clay, sand, and sometimes fossil shells, which prove that they were beds spread out under water. Clay is a naturally occurring material composed primarily of fine-grained Minerals which show plasticity through a variable range of Water content, and FOSSIL is a standard protocol for allowing serial communication for Telecommunications programs under the DOS Operating system.
During some volcanic eruptions a layer of ashes several feet in thickness is deposited over a considerable district, but such beds thin out rapidly as the distance from the crater increases, and ash deposits covering many square miles are usually very thin. The showers of ashes often follow one another after longer or shorter intervals, and hence thick masses of tuff, whether of subaerial or of marine origin, have mostly a stratified character. Stratigraphy, a branch of Geology, studies rock layers and layering ( stratification) The coarsest materials or agglomerates show this least distinctly; in the fine beds it is often developed in great perfection.
Igneous rock
Apart from adventitious material, such as fragments of the older rocks, pieces of trees, etc. , the contents of an ash deposit may be described as consisting of more or less crystalline igneous rocks. In Materials science, a crystal is a Solid in which the constituent Atoms Molecules or Ions are packed in a regularly ordered repeating Igneous rocks (etymology from Latin ignis, fire are rocks formed by solidification of cooled Magma (molten rock If the lava within the crater has been at such a temperature that solidification has commenced, crystals are usually present. They may be of considerable size like the grey, rounded leucite crystals found on the sides of Vesuvius. Leucite is a rock -forming Mineral composed of Potassium and Aluminium tectosilicate K Many of these are very perfect and rich in faces because they grew in a medium that was liquid and not very viscous. Good crystals of augite and olivine are also to be obtained in the ash beds of Vesuvius and of many other volcanoes, ancient and modern. Augite is a single chain inosilicate Mineral described chemically as (CaMgFeSiO3 or Calcium Magnesium Iron The Mineral olivine (when gem-quality also called Peridot) is a Magnesium Iron silicate with the formula ( Mg Blocks of these crystalline minerals (anorthite, olivine, augite and hornblende) are common objects in the tuffs of many of the West Indian volcanoes. Anorthite is a compositional variety of Plagioclase Feldspar. Hornblende is a complex inosilicate series of Minerals Hornblende is not a recognized mineral in its own right but the name is used as a general or field term to India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country Where crystals are very abundant the ashes are called "crystal tuffs. " In St. Vincent and Martinique in 1902, much of the dust was composed of minute crystals enclosed in thin films of glass because the lava at the moment of eruption had very nearly solidified as a crystalline mass. Year 1902 ( MCMII) was a Common year starting on Wednesday (link will display calendar of the Gregorian calendar (or a Common year starting Glass in the common sense refers to a Hard, Brittle, transparent Solid, such as that used for Windows many Some basaltic volcanoes, on the other hand, have ejected great quantities of black glassy scoria, which, after consolidation, weather to a red soft rock known as palagonite; tuffs of this kind occur in Iceland and Sicily. Basalt (bəˈsɔːlt ˈbeisɔːlt ˈbæsɔːlt is a common Extrusive Volcanic rock. Scoria is a textural term for macrovesicular Volcanic rock. It is commonly but not exclusively Basaltic or andesitic in composition Palagonite is an alteration product from the interaction of water with Volcanic glass of chemical composition similar to Basalt. Iceland, officially the Republic of Iceland ( ( Ísland or Lýðveldið Ísland ( Sicily ( Italian and Sicilian: Sicilia) is an autonomous region of Italy. In the Lipari Islands and Hungary there are acid (rhyolitic) tuffs, of pale grey or yellow color, largely composed of lumps and fragments of pumice. The Aeolian Islands ( Italian Isole Eolie) are a Volcanic Archipelago in the Tyrrhenian Sea north of Sicily. Hungary (Magyarország 'mɔɟɔrorsaːg) officially in English the Republic of Hungary ( Magyar Köztársaság, literally Magyar (Hungarian Republic In Computer science, ACID ( Atomicity Consistency Isolation Durability) is a set of properties that guarantee that Database transactions are This page is about a volcanic rock For the ghost town see Rhyolite Nevada, and for the satellite system see Rhyolite/Aquacade. Pumice is a textural term for a volcanic rock that is a solidified frothy lava composed of highly microvesicular glass Pyroclastic with very thin translucent Over a large portion of the sea bottom the beds of fine mud contain small, water-worn, rounded pebbles of very spongy volcanic glass; these have been floated from the shore or cast out by submarine volcanoes, and may have travelled for hundreds of miles before sinking; it has been proved by experiment that some kinds of pumice will float on sea-water for more than a year. The deep sea-deposit known as the "red clay" is largely of volcanic origin and might be suitably described as a "submarine tuff-bed. "
Welded tuff
Welded tuff is a pyroclastic rock, of any origin, that was sufficiently hot at the time of deposition to weld together. Pyroclastic rocks or pyroclastics (derived from the Greek πῦρ, meaning fire and κλαστός, meaning broken are Clastic rocks Strictly speaking, if the rock contains scattered pea-sized fragments or fiamme in it, it is called a welded lapilli-tuff. Welded tuffs (and welded lapilli-tuffs) can be of fallout origin, or deposited from pyroclastic density currents, as in the case of ignimbrites. During welding, the glass shards and pumice fragments adhere together (necking at point contacts), deform, and compact together, resulting in a 'eutaxitic fabric' (see image and contrast with the ash shapes in unwelded tuff).
Welded ignimbrites can be highly voluminous, such as the Lava Creek Tuff erupted from Yellowstone Caldera in Wyoming 640,000 years ago. Lava Creek Tuff is a Tuff formation created when the Yellowstone Caldera erupted about 640000 years ago The Yellowstone Caldera is the volcanic Caldera in Yellowstone National Park in the United States. The State of Wyoming ( is a sparsely populated state in the western region of the United States. Lava Creek Tuff is known to be at least 1000 times as large as the deposits of Mount St. Helens's May 18, 1980 eruption, and it had a Volcanic Explosivity Index (VEI) of 8 -- greater than any eruption known in the last 10,000 years. Lava Creek Tuff is a Tuff formation created when the Yellowstone Caldera erupted about 640000 years ago Mount St Helens is an active Stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States The Volcanic Explosivity Index (VEI was devised by Chris Newhall of the U The intensity of welding may decrease towards the upper margin of a deposit, may decrease towards areas in which the deposit is thinner, and with distance from source. Welded tuff is commonly rhyolitic in composition, but examples of all compositions are known.
Rhyolite tuffs
For petrographical purposes tuffs are generally classified according to the nature of the volcanic rock of which they consist; this may be the same as the accompanying lavas if any were emitted during an eruption, and if there is a change in the kind of lava which is poured out, the tuffs also indicate this equally clearly. In Geology, petrology (from Greek πέτρα petra, rock and λόγος logos, knowledge is the study of rocks and the conditions on which Rhyolite tuffs contain pumiceous, glassy fragments and small scoriae with quartz, alkali feldspar, biotite, etc. Quartz (from German) is the most abundant Mineral in the Earth 's Continental crust (although Feldspar is more common in In Chemistry, an alkali (from Arabic: Al-Qaly القلي القالي) is a basic, ionic salt of an Alkali metal Feldspar is the name of a group of rock-forming Minerals which make up as much as 60% of the Earth 's crust. Biotite is a common phyllosilicate Mineral within the Mica group with the approximate chemical formula K(Mg Fe3AlSi3O10(F Iceland, Lipari, Hungary, the Basin and Range of the American southwest, and New Zealand are among the areas where such tuffs are prominent. Basin and range is a geologic term for a type of Topography characterized by a series of separate and parallel mountain ranges with broad valleys interposed extending New Zealand is an Island country in the south-western Pacific Ocean comprising two main landmasses (the North Island and the South Island The broken pumice is clear and isotropic, and very small particles commonly have crescentic, sickle-shaped, or biconcave outlines, showing that they are produced by the shattering of a vesicular glass, sometimes described as ash-structure. The tiny glass fragments derived from broken pumice are called shards; the glass shards readily deform and flow when the deposits are sufficiently hot, as shown in the accompanying image of welded tuff.
In the ancient rocks of Wales, Charnwood, the Pentland Hills, etc. The Pentland Hills are a range of hills to the south-west of Edinburgh, Scotland. , similar tuffs are known, but in all cases they are greatly changed by silicification (which has filled them with opal, chalcedony and quartz) and by devitrification. OPAL ( Open Pool Australian Lightwater reactor) is a 20 megawatt pool-type nuclear research reactor that was officially opened in April 2007 Chalcedony is a Cryptocrystalline form of Silica, composed of very fine intergrowths of the minerals Quartz and Moganite. The frequent presence of rounded corroded quartz crystals, such as occur in rhyolitic lavas, helps to demonstrate their real nature.
Trachyte tuffs
Trachyte tuffs contain little or no quartz but much sanidine or anorthoclase and sometimes oligoclase feldspar, with occasional biotite, augite and hornblende. Sanidine is the high temperature form of potassium Feldspar (KNa(SiAl4O8 See also List of minerals In weathering they often change to soft red or yellow clay-stones, rich in kaolin with secondary quartz. Kaolinite is a Clay mineral with the chemical composition Al 2 Si 2 O 5( OH)4 Recent trachyte tuffs are found on the Rhine (at Siebengebirge), in Ischia, near Naples, Hungary, etc. The Rhine (Rhein Rijn Rhin Reno Rain Rhenus is one of the longest and most important Rivers in Europe at 1320 kilometres (820 mi with an average discharge The Siebengebirge (lit "seven mountains" in German) is a German Range of hills to the East of the Rhine, southeast of Bonn For the comune see Ischia (comune. For the part of the human hip see Ischium Ischia is a Volcanic Island in the Naples ( Napoli, Neapolitan: Nàpule) is a historic City in southern Italy, the Capital of the Hungary (Magyarország 'mɔɟɔrorsaːg) officially in English the Republic of Hungary ( Magyar Köztársaság, literally Magyar (Hungarian Republic
Andesitic tuffs
Andesitic tuffs are exceedingly common. They occur along the whole chain of the Cordilleras and Andes, in the West Indies, New Zealand, Japan, etc. The American cordillera consists of an essentially continuous sequence of Mountain ranges that form the western "backbone" of North America, Central The Andes form the world's longest exposed Mountain range. They lie as a continuous chain of highland along the western coast of South America. The Caribbean (ˌkærəˡbiən kæ'rəbiən Cariben|Caraïben or Caraïben; Caraïbe or more commonly Antilles; Caribe is a Region consisting In the Lake district, North Wales, Lorne, the Pentland Hills, the Cheviots and many other districts of Great Britain, ancient rocks of exactly similar nature are abundant. See also Kingdom of Great Britain Great Britain (Breatainn Mhòr Prydain Fawr Breten Veur Graet Breetain is the larger of the two main islands In color they are red or brown; their scoriae fragments are of all sizes from huge blocks down to minute granular dust. The cavities are filled up with many secondary minerals, such as calcite, chlorite, quartz, epidote, chalcedony: but in microscopic sections the nature of the original lava can nearly always be made out from the shapes and properties of the little crystals which occur in the decomposed glassy base. Calcite is a carbonate mineral and the most stable polymorph of Calcium carbonate ( Ca[[carbon C]] O 3 The chlorites are a group of phyllosilicate Minerals Chlorites can be described by the following four endmembers based on their chemistry via substitution Epidote is a Calcium Aluminium Iron sorosilicate Mineral, Ca2Al2(Fe3+Al(SiO4(Si2O7O(OH Even in the smallest details these ancient tuffs have a complete resemblance to the modern ash beds of Cotopaxi, Krakatoa and Mont Pelé. Cotopaxi is a Stratovolcano in the Andes Mountains, located about 75 kilometres (50 mi south of Quito, Ecuador, South America Krakatoa ( Indonesian: Krakatau) also spelled Krakatao or Krakatowa, is a volcanic island in the Sunda Strait
Basaltic tuffs
Basaltic tuffs are also of wide spread occurrence both in districts where volcanoes are now active and in lands where eruptions have long since ended. They are found in Skye, Mull, Antrim and other places, where there are tertiary volcanic rocks; in Scotland, Derbyshire and Ireland among the carboniferous strata; and among the still older rocks of the Lake District, southern uplands of Scotland and Wales. Skye or the Isle of Skye ( Scottish Gaelic An t-Eilean Sgitheanach əɲ tʰʲelan s̪kʲiə The Isle of Mull (or simply Mull; Muile in Scottish Gaelic) is the second largest Island of the Inner Hebrides, off the County Antrim ( Contae Aontroma or simply Aontroim in Irish) is one of six counties that form Northern Ireland, and one of nine counties The chuprichondira geological time interval covers roughly the time span between the demise of the non- avian Dinosaurs and beginning of the most recent Ice Age, approximately Scotland ( Gaelic: Alba) is a Country in northwest Europethat occupies the northern third of the island of Great Britain. History The area that is now Derbyshire was first visited probably briefly by humans 200000 years ago during the Aveley Interglacial as evidenced by a Middle Ireland (pronounced /ˈaɾlənd/ Éire) is the third largest island in Europe, and the twentieth-largest island in the world The Carboniferous is a geologic period and system that extends from the end of the Devonian period about 359 The Lake District, also known as The Lakes or Lakeland, is a rural area in North West England. They are black, dark green or red in colour; vary greatly in coarseness, some being full of round spongy bombs a foot or more in diameter, and, being often submarine, may contain shale, sandstone, grit and other sedimentary material, and are occasionally fossiliferous. Recent basaltic tuffs are found in Iceland, the Faroe Islands, Jan Mayen, Sicily, Sandwich Islands, Samoa, etc. The Faroe Islands or Faeroe Islands or simply Faroe(s or Faeroes (Føroyar meaning " Sheep Islands" Færøerne Old Norse Jan Mayen Island is a 55 km (34 miles long (southwest-northeast and 373 km² (144 mi²) in area Arctic Volcanic island in the "Sandwich Island" redirects here Sandwich Island is also an early name for the Cook Islands island of Manuae, and for the island of Efate Samoa, officially the Independent State of Samoa, is a country governing the western part of the Samoan Islands Archipelago in the South Pacific Ocean When weathered they are filled with calcite, chlorite, serpentine and, especially where the lavas contain nepheline or leucite, are often rich in zeolites, such as analcite, prehnite, natrolite, scolecite, chabazite, heulandite, etc. The serpentine group describes a group of common rock-forming hydrous Magnesium Iron phyllosilicate (()3 Minerals they Nepheline, also called nephelite (from Greek: nephos, "cloud" is a Feldspathoid: a silica-undersaturated aluminosilicate Na Leucite is a rock -forming Mineral composed of Potassium and Aluminium tectosilicate K Zeolites (Greek zein, "to boil" lithos, "a stone" are hydrated Aluminosilicate Minerals and have a micro-porous structure Analcime or analcite (from the Greek analkimos - "weak" is a white grey or colourless tectosilicate Mineral. Prehnite is a phyllosilicate of Calcium and Aluminium with the formula Ca2Al(AlSi3O10(OH2 Natrolite is a tectosilicate Mineral species belonging to the Zeolite group Scolecite is a tectosilicate Mineral belonging to the Zeolite group a hydrated Calcium Silicate, Ca Al 2 Chabazite is a tectosilicate Mineral of the Zeolite group with formula (CaNa2K2MgAl2Si4O12·6H2O Heulandite is the name of a series of tecto-silicate Minerals of the Zeolite group
Ultramafic tuffs
Ultramafic tuffs are extremely rare; their characteristic is the abundance of olivine or serpentine and the scarcity or absence of feldspar and quartz. The Mineral olivine (when gem-quality also called Peridot) is a Magnesium Iron silicate with the formula ( Mg The serpentine group describes a group of common rock-forming hydrous Magnesium Iron phyllosilicate (()3 Minerals they Feldspar is the name of a group of rock-forming Minerals which make up as much as 60% of the Earth 's crust. Quartz (from German) is the most abundant Mineral in the Earth 's Continental crust (although Feldspar is more common in Rare occurrences may include unusual surface deposits of maars of kimberlites of the diamond-fields of southern Africa and other regions. A maar is a broad low- Relief Volcanic crater that is caused by a Phreatomagmatic eruption, an Explosion caused by Groundwater Kimberlite is a type of potassic Volcanic rock best known for sometimes containing Diamonds It is named after the town of Kimberley in South Africa In Mineralogy, diamond is the allotrope of carbon where the carbon atoms are arranged in The principal rock of kimberlite is a dark bluish green serpentine-rich breccia (blue-ground) which when thoroughly oxidized and weathered becomes a friable brown or yellow mass (the "yellow-ground"). Kimberlite is a type of potassic Volcanic rock best known for sometimes containing Diamonds It is named after the town of Kimberley in South Africa These breccias were emplaced as gas-solid mixtures and are typically preserved and mined in diatremes that form intrusive pipe-like structures. A diatreme is a breccia filled Volcanic pipe that was formed by a gaseous explosion At depth, some kimberlite breccias grade into root zones of dikes made of unfragmented rock. At the surface, ultramafic tuffs may occur in maar deposits. A maar is a broad low- Relief Volcanic crater that is caused by a Phreatomagmatic eruption, an Explosion caused by Groundwater Because kimberlites are the most common igneous source of diamonds, the transitions from maar to diatreme to root-zone dikes have been studied in detail. Diatreme-facies kimberlite is more properly called an ultramafic breccia rather than a tuff.
Folding and metamorphism
In course of time other changes than weathering may overtake tuff deposits. Sometimes they are involved in folding and become sheared and cleaved. Many of the green slates of the lake district in Cumberland are fine cleaved ashes. Slate is a fine-grained foliated homogeneous, Metamorphic rock derived from an original Shale -type Sedimentary rock composed of Clay Cumberland is one of the 39 Historic counties of England. It formed an administrative county from 1889 to 1974 (excluding Carlisle from 1915 and now forms part of In Charnwood forest also the tuffs are slaty and cleaved. The green color is due to the large development of chlorite. Among the crystalline schists of many regions green beds or green schists occur, which consist of quartz, hornblende, chlorite or biotite, iron oxides, feldspar, etc. The schists form a group of medium-grade Metamorphic rocks chiefly notable for the preponderance of lamellar Minerals such as Micas chlorite Altogether there are sixteen known Iron Oxides and oxyhydroxides , and are probably recrystallized or metamorphosed tuffs. Metamorphism can be defined as the solid state recrystallisation of pre-existing rocks due to changes in heat and/or pressure and/or introduction of fluids i They often accompany masses of epidiorite and hornblende-schists which are the corresponding lavas and sills. In Geology, a sill is a tabular Pluton that has intruded between older layers of Sedimentary rock, beds of Volcanic Some chlorite-schists also are probably altered beds of volcanic tuff. The "Schalsteins" of Devon and Germany include many cleaved and partly recrystallized ash-beds, some of which still retain their fragmental structure though their lapilli are flattened and drawn out. Devon is a large county in the South West of England. The county is also referred to as Devonshire, but that is an entirely unofficial name Their steam cavities are usually filled with calcite, but sometimes with quartz. The more completely altered forms of these rocks are platy, green chloritic schists; in these, however, structures indicating their original volcanic nature only sparingly occur. These are intermediate stages between cleaved tuffs and crystalline schists.
Practical uses
In the ancient world, tuff's relative softness meant that it was commonly used for construction where it was available. Tufa is common in Italy, and the Romans used it for many buildings and bridges. Italy (Italia officially the Italian Republic, (Repubblica Italiana is located on the Italian Peninsula in Southern Europe, and on the two largest Ancient Rome was a Civilization that grew out of a small agricultural community founded on the Italian Peninsula as early as the 10th century BC For example, the whole port of the island of Ventotene (still in use), was carved out from tuff. Ventotene is an island in the Tyrrhenian Sea, off the coast of Campania, Italy. The Servian Wall, built to defend the city of Rome in the 4th century BC, is also built almost entirely from tuff. The Servian Wall (in Latin: Murus Servii Tullii) was a defensive barrier constructed around the city of Rome in the early 4th century BC. Rome ( Roma ˈroma Roma is the capital city of Italy and Lazio, and is Italy's largest and most populous city with more than 2 The 4th century BC started the first day of 400 BC and ended the last day of 301 BC. The Romans also cut tuff into small rectangular stones that they used to create walls in a pattern known as opus reticulatum. Opus reticulatum (also known as reticulated work) is a form of Brickwork used in ancient Roman architecture.
The Romans thought bees nested in tuff. The substance is mentioned in the Aeneid (Book XII, ln 805). For the group of nine Ancient Egyptian deities see Ennead. The Aeneid (əˈniːɪd in
Economic importance
Yucca Mountain Repository, a U. S. Department of Energy terminal storage facility for spent nuclear reactor and other radioactive waste, is in tuff and ignimbrite in the Basin and Range Province in Nevada. Ignimbrite is a Volcanic Pyroclastic rock often of Dacitic or Rhyolitic composition The Basin and Range Province is a large geologic province which includes parts of the southwestern United States and northwestern Mexico, typified by Basin and Nevada ( is a state located in the western region of the United States of America. In Napa valley and Sonoma valley, California, areas made out of tuff are routinely excavated for storage of wine barrels. Napa County is a County located north of the San Francisco Bay Area in the U California ( is a US state on the West Coast of the United States, along the Pacific Ocean.
Tuff from Rano Raraku was used by the Rapa Nui people of Easter Island to make the vast majority of their famous Moai (statues). Rano Raraku is a volcanic crater formed of consolidated Volcanic ash, or Tuff, and located on the lower slopes of Terevaka in the Rapa Nui National Moai (or mo‘ai) (ˈmoʊаɪ are Monolithic human figures carved from rock on the Polynesian island of Rapa Nui (Easter Island
Otherwise, tuffs are not of much importance in an economic sense. The peperino, much used at Rome and Naples as a building stone, is a trachyte tuff. Peperino is an Italian name applied to a brown or grey Volcanic Tuff, containing fragments of Basalt and Limestone, with disseminated Trachyte is an Igneous, Volcanic rock with an Aphanitic to Porphyritic texture Pozzolana also is a decomposed tuff, but of basic character, originally obtained near Naples and used as a cement, but this name is now applied to a number of substances not always of identical character. Pozzolana, also known as pozzolanic ash is a fine sandy Volcanic ash, originally discovered and dug in Italy at Pozzuoli in the region around Naples ( Napoli, Neapolitan: Nàpule) is a historic City in southern Italy, the Capital of the In the most general sense of the word a cement is a binder a substance which sets and hardens independently and can bind other materials together In the Eifel region of Germany a trachytic, pumiceous tuff called trass has been extensively worked as a hydraulic mortar. The Eifel is a low mountain range in western Germany. It occupies parts of southwestern North Rhine-Westphalia and northwestern Rhineland-Palatinate Trass is the local name of a Volcanic Tuff occurring in the Eifel, where it is worked for hydraulic mortar. Mortar is a workable paste formed by mixture of Cement, Water and fine aggregate Masonry to bind construction blocks together and fill the gaps between
See also
References
This article incorporates text from the Encyclopædia Britannica Eleventh Edition, a publication now in the public domain. This is a List of Minerals for which there are Wikipedia articles Scoria is a textural term for macrovesicular Volcanic rock. It is commonly but not exclusively Basaltic or andesitic in composition Lava is molten rock expelled by a Volcano during an eruption When first expelled from a volcanic vent it is a Liquid at Temperatures Sillar is a whitish Volcanic stone from which many colonial buildings in the city of Arequipa, Peru, are made Lapilli is a size classification term for Tephra, which is material that falls out of the air during a volcanic eruption. A pyroclastic flow (also known as a pyroclastic density current) is a common and devastating result of some volcanic eruptions. The Bishop Tuff is located in the Owens Valley, southeast of Mammoth Lakes California. The Encyclopædia Britannica Eleventh Edition (1910–1911 is a 29-volume reference work that marked the beginning of the Encyclopædia Britannica The public domain is a range of abstract materials &ndash commonly referred to as Intellectual property &ndash which are not owned or controlled by anyone
Dictionary
tuff
-noun
- (geology) A rock composed of compacted volcanic ash varying in size from fine sand to coarse gravel.
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