Type locality, also called type area, is the

locality Locality may refer to: * Locality, a historical named location or place in Canada * Locality (association), an association of community regeneration organizations in England * Locality (linguistics) * Locality (settlement) * Suburbs and localitie ...

where a particular

rock type In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition, and the way in which it is formed. Rocks form the Earth's o ...

stratigraphic unit A stratigraphic unit is a volume of rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrographic, lithologic or paleontologic features ( facies) that characteriz ...

mineral species In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...

is first identified. If the stratigraphic unit in a locality is layered, it is called a

stratotype In geology, a stratotype or type section is the physical location or outcrop of a particular reference exposure of a stratigraphic sequence or stratigraphic boundary. If the stratigraphic unit is layered, it is called a stratotype, whereas the ...

, whereas the standard of reference for unlayered rocks is the type locality. The concept is similar to

type site In archaeology, a type site (American English) or type-site (British English) is the site used to define a particular archaeological culture or other typological unit, which is often named after it. For example, discoveries at La Tène and H ...

archaeology Archaeology or archeology is the study of human activity through the recovery and analysis of material culture. The archaeological record consists of Artifact (archaeology), artifacts, architecture, biofact (archaeology), biofacts or ecofacts, ...

Examples of geological type localities

Rocks and minerals

Aragonite Aragonite is a carbonate mineral and one of the three most common naturally occurring crystal forms of calcium carbonate (), the others being calcite and vaterite. It is formed by biological and physical processes, including precipitation fr ...

Molina de Aragón Molina de Aragón is a municipality located in the province of Guadalajara, Castile-La Mancha, Spain. According to the 2009 census ( INE), the municipality had a population of 3,671 inhabitants. It held the record (−28.2 °C) for the lowes ...

, Guadalajara, Spain *

Autunite Autunite (hydrated calcium uranyl phosphate), with formula Ca(UO2)2(PO4)2·10–12H2O, is a yellow-greenish fluorescent phosphate mineral with a hardness of 2–. Autunite crystallizes in the orthorhombic system and often occurs as tabular squa ...

Autun Autun () is a Subprefectures in France, subprefecture of the Saône-et-Loire Departments of France, department in the Bourgogne-Franche-Comté Regions of France, region of central-eastern France. It was founded during the Principate era of the e ...

, France *

Benmoreite Benmoreite is a volcanic rock of intermediate composition. It is a silica-undersaturated sodium-rich variety of trachyandesite (the other kind is latite) and belongs to the alkaline suite of igneous rocks. It was named after Ben More, a mount ...

Ben More (Mull) Ben More (, meaning "great mountain") is the highest mountain and only Munro (mountains in Scotland that reach an elevation of at least ) on the Isle of Mull, Scotland. It is also the highest peak in the Islands of Scotland, Scottish isles – a ...

, Scotland * Blairmorite:

Blairmore, Alberta Blairmore is a community in the Rocky Mountains within the Crowsnest Pass, Alberta, Municipality of Crowsnest Pass in Southern Alberta, southwest Alberta, Canada. It was formerly incorporated as a town prior to 1979 when it amalgamated with four o ...

, Canada *

Boninite Boninite is an extrusive rock high in both magnesium and silica, thought to be usually formed in fore-arc environments, typically during the early stages of subduction. The rock is named for its occurrence in the Izu-Bonin arc south of Japan. ...

Bonin Islands The Bonin Islands, also known as the , is a list of islands of Japan, Japanese archipelago of over 30 subtropical and Island#Tropical islands, tropical islands located around SSE of Tokyo and northwest of Guam. The group as a whole has a total ...

, Japan *

Comendite Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite. Phenocrysts are sodic sanidine with minor albite and bipyramidal quartz. Iddings, Joseph Paxson, 1913, ''Igneous rocks: composition, texture and classification'', v ...

: Comende,

San Pietro Island San Pietro Island (Italian language, Italian: ''Isola di San Pietro'', Ligurian (Romance language), Ligurian Tabarchino: ''Uiza de San Pé'', Sardinian language, Sardinian: ''Isula 'e Sàntu Pèdru'') is an island approximately off the South ...

Sardinia Sardinia ( ; ; ) is the Mediterranean islands#By area, second-largest island in the Mediterranean Sea, after Sicily, and one of the Regions of Italy, twenty regions of Italy. It is located west of the Italian Peninsula, north of Tunisia an ...

Cummingtonite Cummingtonite ( ) is a metamorphic amphibole with the chemical composition , magnesium iron silicate hydroxide. Monoclinic cummingtonite is compositionally similar and polymorphic with orthorhombic anthophyllite, which is a much more common ...

Cummington, Massachusetts Cummington is a New England town, town in Hampshire County, Massachusetts, United States. The population was 829 at the 2020 United States census, 2020 census, a decline from the figure of 872 tabulated in 2010. It is part of the Springfield, Mas ...

Dunite Dunite (), also known as olivinite (not to be confused with the mineral olivenite), is an intrusive igneous rock of ultramafic composition and with phaneritic (coarse-grained) texture. The mineral assemblage is greater than 90% olivine, wit ...

Dun Mountain Dun Mountain is a mountain in the Richmond Range near the city of Nelson in the Tasman District of New Zealand's South Island. It is located between the catchments of the Pelorus, Maitai and Roding Rivers. The mountain is named for its brown ( ...

, New Zealand *

Essexite Essexite (), also called nepheline monzogabbro (), is a dark gray or black holocrystalline plutonic igneous rock. Its name is derived from the type locality in Essex County, Massachusetts, in the United States. Modern petrology identifies roc ...

Essex County, Massachusetts Essex County is a County (United States), county in the northeastern part of the U.S. state of Massachusetts. At the 2020 United States census, 2020 census, the total population was 809,829, making it the third-most populous county in the stat ...

, US *

Fayalite Fayalite (, commonly abbreviated to Fa) is the iron-rich endmember, end-member of the olivine solid solution, solid-solution series. In common with all minerals in the olivine, olivine group, fayalite crystallizes in the orthorhombic system (spac ...

: Horta,

Fayal Island Faial Island (), also known as Fayal Island, is a Portugal, Portuguese island of the Central Group or ''Grupo Central'' of the Azores, in the Atlantic Ocean. The Capelinhos volcano is the westernmost point of the island and is considered the we ...

, Azores, Portugal *

Harzburgite Harzburgite, an ultramafic, igneous rock, is a variety of peridotite consisting mostly of the two minerals olivine and low-calcium (Ca) pyroxene ( enstatite); it is named for occurrences in the Harz Mountains of Germany. It commonly contains a ...

Bad Harzburg Bad Harzburg (; Eastphalian dialect, Eastphalian: ''Bad Harzborch'') is a spa town in central Germany, in the Goslar (district), Goslar district of Lower Saxony. It lies on the northern edge of the Harz mountains and is a recognised saltwater spa ...

, Germany * Icelandite: Thingmuli (Þingmúli), Iceland *

Ijolite Ijolite is an igneous rock consisting essentially of nepheline and augite. Ijolite is a rare rock type of considerable importance from a mineralogical and petrological standpoint. The word is derived from the first syllable of the Finnish words su ...

: Iivaara,

Kuusamo Kuusamo (; ; ; ) is a List of cities and towns in Finland, town and municipalities of Finland, municipality in Finland. It is located in Koillismaa, the northeastern part of the Northern Ostrobothnia regions of Finland, region. The municipality h ...

, Finland *

Kimberlite Kimberlite is an igneous rock and a rare variant of peridotite. It is most commonly known as the main host matrix for diamonds. It is named after the town of Kimberley, Northern Cape, Kimberley in South Africa, where the discovery of an 83.5-Car ...

Kimberley, Northern Cape Kimberley is the Capital city, capital and largest city of the Northern Cape province of South Africa. It is located approximately 110 km east of the confluence of the Vaal River, Vaal and Orange Rivers. The city has considerable historica ...

, South Africa *

Komatiite Komatiite is a type of ultramafic mantle-derived volcanic rock defined as having crystallised from a lava of at least 18 wt% magnesium oxide (MgO). It is classified as a 'picritic rock'. Komatiites have low silicon, potassium and aluminium, and ...

Komati River The Komati River, also known as the Inkomati River or Incomati River (in Mozambique, from Portuguese Rio Incomati), is a river in South Africa, Eswatini and Mozambique. Originating in north-western Eswatini, it is joined by the Crocodile Riv ...

, South Africa *

Labradorite Labradorite (( Ca, Na)( Al, Si)4 O8) is a calcium-enriched feldspar mineral first identified in Labrador, Canada, which can display an iridescent effect ( schiller). Labradorite is an intermediate to calcic member of the plagioclase series. It ...

Paul's Island Paul's Island or Paul Island is an island off the coast of Labrador, near the town of Nain in Canada. The island is the geological type area of the mineral labradorite, which is a plagioclase feldspar. Labradorite is the principal component ...

, Labrador, Canada *

Lherzolite Lherzolite is a type of ultramafic igneous rock. It is a coarse-grained rock consisting of 40 to 90% olivine along with significant orthopyroxene and lesser amounts of calcic chromium-rich clinopyroxene. Minor minerals include chromium and alumi ...

Étang de Lers Étang de Lers or Lake of Lers is a natural lake in the Ariège department (France). Geology Lherzolite Lherzolite is a type of ultramafic igneous rock. It is a coarse-grained rock consisting of 40 to 90% olivine along with significant ort ...

, France (Old spelling was: Étang de Lherz.) *

Mimetite Mimetite is a lead arsenate chloride mineral () which forms as a secondary mineral in lead deposits, usually by the Redox, oxidation of galena and arsenopyrite. The name derives from the Greek ''mimetes'', meaning "imitator" and refers to mimeti ...

: ''Treue Freundschaft Mine'',

Johanngeorgenstadt Johanngeorgenstadt (, ) is a mining town in Saxony’s Ore Mountains, 17 km south of Aue, and 27 km northwest of Karlovy Vary. It lies in the district of Erzgebirgskreis, on the border with the Czech Republic, is a state-recognized hea ...

, Germany *

Mugearite Mugearite () is a type of oligoclase-bearing basalt, comprising olivine, apatite, and opaque oxides. The main feldspar in mugearite is oligoclase. Mugearite is a sodium-rich member of the alkaline magma series. In the TAS classification of volc ...

Mugeary Mugeary () is a farm or croft and former settlement on the island of Skye, Scotland. Located southwest of Portree, it is known as the location where the basaltic rock mugearite was first identified. The Gaelic name is derived from Old Norse a ...

, Skye, Scotland *

Mullite Mullite or porcelainite is a rare silicate mineral formed during contact metamorphism of clay minerals. It can form two stoichiometric forms: 3 Al2 O32 SiO2 or 2Al2O3 SiO2. Unusually, mullite has no charge-balancing cations present. As a result ...

Isle of Mull The Isle of Mull or simply Mull ( ) is the second-largest island of the Inner Hebrides (after Skye) and lies off the west coast of Scotland in the Council areas of Scotland, council area of Argyll and Bute. Covering , Mull is the fourth-lar ...

, Scotland] *

Pantellerite Pantellerite is a type of volcanic rock, specifically a peralkaline rhyolite. It has a higher iron and lower aluminium composition than comendite. It is named after Pantelleria, a volcanic island in the Strait of Sicily and the Type locality (geo ...

Pantelleria Pantelleria (; ), known in ancient times as Cossyra or Cossura, is an Italian island and comune in the Strait of Sicily in the Mediterranean Sea, southwest of Sicily and east of the Tunisian coast. On clear days Tunisia is visible from the ...

, off Sicily *

Portlandite Portlandite is a hydroxide-bearing mineral typically included in the oxide mineral class. It is the naturally occurring form of calcium hydroxide (Ca(OH)2) and the calcium analogue of brucite (Mg(OH)2). Occurrence Portlandite occurs in a variety ...

Scawt Hill Scawt Hill is a volcanic plug in County Antrim, Northern Ireland, in the borough of Larne, 5 km from the village of Ballygally. It gets its name from the Ulster Scots "" meaning scaly, scabby or rugged. Alternatively, '' 'scawt' '' meaning ...

, Ballygalley, Larne, County Antrim, Northern Ireland *

Rodingite Rodingite is a metasomatic rock composed of grossular- andradite garnet, calcic pyroxene, vesuvianite, epidote and scapolite. Rodingites are common where mafic rocks are in proximity to serpentinized ultramafic rocks. The mafic rocks are altered ...

Roding River The Roding River is a river of the Tasman Region of New Zealand's South Island. It flows generally southwest from its sources in the hills above the city of Nelson, reaching the Wairoa River five kilometres south of Richmond. The rock type Rodin ...

, New Zealand * Sovite:

Norsjø Norsjø is a lake in the municipalities of Skien, Nome, and Midt-Telemark in Telemark county, Norway. The lake sits at an elevation of above sea level. Norsjø is part of the Telemark Canal. Most rivers in Telemark flow into the lake Norsj� ...

, Norway *

Strontianite Strontianite (Strontium, SrCarbon, COxygen, O3) is an important raw material for the extraction of strontium. It is a rare carbonate mineral and one of only a few strontium minerals. It is a member of the aragonite group. Aragonite group membe ...

Strontian Strontian (; ) is the main village in Sunart, an area in western Lochaber, Scottish Highlands, Highland, Scotland, on the A861 road. Prior to 1975 it was part of Argyllshire. It lies on the north shore of Loch Sunart, close to the head of th ...

, Scotland (also the element

strontium Strontium is a chemical element; it has symbol Sr and atomic number 38. An alkaline earth metal, it is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is exposed to ...

derived from the mineral) *

Temagamite Temagamite is a bright white palladium mercury telluride mineral with a hardness of on the Mohs scale. Its chemical formula is Pd3 Hg Te3. It was discovered at the Temagami Mine on Temagami Island, Lake Temagami in 1973, and it represents a r ...

Copperfields Mine Copperfields Mine, originally known as Temagami Mine, is an abandoned copper and silver mine on Temagami Island in Lake Temagami, Ontario, Canada. The mine opened in 1955 and comprises both underground and surface workings within a sulfide ore bod ...

Temagami Temagami, formerly spelled Timagami, is a municipality in northeastern Ontario, Canada, in the Nipissing District with Lake Temagami at its heart. The Temagami region is known as ''n'Daki Menan'', the homeland of the area's First Nations com ...

, Ontario, Canada *

Tilleyite Tilleyite is a rarely occurring calcium sorosilicate mineral with formula (sometimes represented as ). It is chemically a calcium silicate with additional carbonate ions. Tilleyite crystallizes in the monoclinic crystal system and forms only po ...

: Crestmore Quarry, Riverside County, California *

Tonalite Tonalite is an igneous rock, igneous, plutonic (Intrusive rock, intrusive) rock (geology), rock, of felsic composition, with phaneritic (coarse-grained) texture. Feldspar is present as plagioclase (typically oligoclase or andesine) with alkali fe ...

Tonale Pass Tonale Pass () (el. 1883 m./6178 ft.) is a high mountain pass in northern Italy across the Rhaetian Alps, between Lombardy and Trentino. It connects Valcamonica and Val di Sole. It is delimited by the Ortler Alps to the nort ...

Trondhjemite Trondhjemite is a leucocratic (light-colored) intrusive igneous rock. It is a variety of tonalite in which the plagioclase is mostly in the form of oligoclase. Trondhjemites that occur in the oceanic crust or in ophiolites are usually called pla ...

: Follstad,

Støren is the administrative centre of Midtre Gauldal Municipality in Trøndelag county, Norway. The village is located in the Gauldalen valley at the confluence of the rivers Gaula and ''Sokna''. Støren is located on the European route E06 highw ...

, Norway *

Uraninite Uraninite, also known as pitchblende, is a radioactive, uranium-rich mineral and ore with a chemical composition that is largely UO2 but because of oxidation typically contains variable proportions of U3O8. Radioactive decay of the uranium c ...

: Joachimsthal,

Austria-Hungary Austria-Hungary, also referred to as the Austro-Hungarian Empire, the Dual Monarchy or the Habsburg Monarchy, was a multi-national constitutional monarchy in Central Europe#Before World War I, Central Europe between 1867 and 1918. A military ...

(now

Jáchymov Jáchymov (; or ''Joachimsthal'') is a spa town in Karlovy Vary District in the Karlovy Vary Region of the Czech Republic. It has about 2,300 inhabitants. Jáchymov has a long mining tradition, thanks to which it used to be the second most popu ...

, Czech Republic) *

Websterite Websterite is ultramafic igneous rock, a type of pyroxenite that has less than 5% olivine and roughly equal proportions of orthopyroxene and clinopyroxene. Websterite is named after the town Webster in North Carolina North Carolina ...

: Webster in North Carolina. *

Widgiemoolthalite Widgiemoolthalite is a rare mineral hydration, hydrated nickel(II) carbonate mineral with the chemical formula . Usually bluish-green in color, it is a brittle mineral formed during the weathering of nickel sulfide. Present on gaspéite surfaces, ...

Widgiemooltha, Western Australia Widgiemooltha is an Ghost town, abandoned town in Western Australia east of Perth, Western Australia between Kambalda, Western Australia, Kambalda and Norseman, Western Australia, Norseman in the Goldfields-Esperance region of Western Australi ...

, Australia * Ytterbite (a.k.a. ''gadolinite''):

Ytterby Ytterby () is a village on the Swedish island of Resarö, in Vaxholm Municipality in the Stockholm archipelago. Today the residential area is dominated by suburban homes. The name of the village translates to "outer village". Ytterby is the ...

, Sweden

Formations

Bearpaw Formation The Bearpaw Formation, also called the Bearpaw Shale, is a geologic formation of Late Cretaceous (Campanian) age. It outcrops in the U.S. state of Montana, as well as the Canadian provinces of Alberta and Saskatchewan, and was named for the Bear ...

Bear Paw Mountains The Bears Paw Mountains (Bear Paw Mountains, Bear's Paw Mountains or Bearpaw Mountains) are an insular-montane island range in the Central Montana Alkalic Province in north-central Montana, United States, located approximately 10 miles south of ...

, Montana, US *

Burgess Shale The Burgess Shale is a fossil-bearing deposit exposed in the Canadian Rockies of British Columbia, Canada. It is famous for the exceptional preservation of the soft parts of its fossils. At old (middle Cambrian), it is one of the earliest fos ...

: Burgess Pass on Mount Burgess, Alberta–British Columbia, Canada *

Calvert Formation The Calvert Formation is a Formation (geology), geologic formation in Maryland, Virginia, and Delaware. It preserves fossils dating back to the early to middle Miocene, Miocene epoch of the Neogene Period (geology), period. It is one of the three ...

Calvert Cliffs State Park Calvert Cliffs State Park is a public recreation area in Lusby, Calvert County, Maryland, that protects a portion of the cliffs that extend for 24 miles along the eastern flank of the Calvert Peninsula on the west side of Chesapeake Bay from ...

, Maryland, US *

Chapel Island Formation The Chapel Island Formation is a sedimentary formation from the Burin Peninsula, Newfoundland, Canada. It is a succession of siliciclastic deposits, over thick, that were deposited during the latest Ediacaran and earliest Cambrian. Stratigraph ...

: Newfoundland, Canada *

Chattanooga Shale The Chattanooga Shale is a geological formation in Alabama, Arkansas, Georgia (U.S. state), Georgia, Kansas, Kentucky, Missouri and Tennessee. It preserves conodont fossils dating to the Devonian period. It occurs mostly as a subsurface geologic f ...

Chattanooga, Tennessee Chattanooga ( ) is a city in Hamilton County, Tennessee, United States, and its county seat. It is located along the Tennessee River and borders Georgia (U.S. state), Georgia to the south. With a population of 181,099 in 2020, it is Tennessee ...

, US * Chazy Formation:

Chazy, New York Chazy is a town in northeastern Clinton County, New York, United States. The population was 4,096 at the 2020 census. The closest city is Plattsburgh, to the south. Chazy is south of the Canada–United States border. The ZIP code is 12 ...

, US * Fort Payne Formation:

Fort Payne, Alabama Fort Payne is a city in and county seat of DeKalb County, in northeastern Alabama, United States. It is near Lookout Mountain. At the 2020 census, the population was 14,877. This city developed around a fort of the same name, built in the 183 ...

, US * Gault Formation: Copt Point,

Folkestone Folkestone ( ) is a coastal town on the English Channel, in Kent, south-east England. The town lies on the southern edge of the North Downs at a valley between two cliffs. It was an important harbour, shipping port, and fashionable coastal res ...

, UK *

Holston Formation The Holston Formation, alternately known as the Holston Limestone, is a stratigraphic unit of Ordovician age within the Chickamauga Group in the Ridge-and-Valley physiographic province of the southeastern United States. A long outcrop belt ...

Holston River The Holston River is a river that flows from Kingsport, Tennessee, to Knoxville, Tennessee. Along with its three major forks (North Fork, Middle Fork and South Fork), it comprises a major river system that drains much of northeastern Tennessee ...

, Tennessee, US *

Jacobsville Sandstone Jacobsville Sandstone is a red sandstone formation, marked with light-colored streaks and spots, primarily found in northern Upper Michigan, portions of Ontario, and under much of Lake Superior. Desired for its durability and aesthetics, the sa ...

: Jacobsville, Michigan, US *

Ogallala Formation The Ogallala Formation is a Miocene to early Pliocene geologic formation in the central High Plains of the western United States and the location of the Ogallala Aquifer. In Nebraska and South Dakota it is also classified as the Ogallala Group ...

: High Plains, US *

St. Louis Limestone The St. Louis Limestone is a large geologic formation covering a wide area of the midwest of the United States. It is named after an exposure at St. Louis, Missouri. It consists of sedimentary limestone with scattered chert beds, including the ...

St. Louis, Missouri St. Louis ( , sometimes referred to as St. Louis City, Saint Louis or STL) is an Independent city (United States), independent city in the U.S. state of Missouri. It lies near the confluence of the Mississippi River, Mississippi and the Miss ...

, US * Ste. Genevieve Limestone:

Ste. Genevieve, Missouri Ste. Genevieve ( ) is a city in Ste. Genevieve Township and is the county seat of Ste. Genevieve County, Missouri, United States. The population was 4,999 at the 2020 census. Founded in 1735 by French Canadian colonists and settlers from east ...

, US * Temple Butte Formation: Temple Butte, Grand Canyon, US *

Upper Greensand Formation The Upper Greensand Formation is a Cretaceous formation of Albian to Cenomanian in age, found within the Wessex Basin and parts of the Weald Basin in southern England. It overlies the Gault Clay and underlies the Chalk Group. It varies in thic ...

Weald The Weald () is an area of South East England between the parallel chalk escarpments of the North and the South Downs. It crosses the counties of Hampshire, Surrey, West Sussex, East Sussex, and Kent. It has three parts, the sandstone "High W ...

Sussex Sussex (Help:IPA/English, /ˈsʌsɪks/; from the Old English ''Sūþseaxe''; lit. 'South Saxons'; 'Sussex') is an area within South East England that was historically a kingdom of Sussex, kingdom and, later, a Historic counties of England, ...

Hampshire Hampshire (, ; abbreviated to Hants.) is a Ceremonial counties of England, ceremonial county in South East England. It is bordered by Berkshire to the north, Surrey and West Sussex to the east, the Isle of Wight across the Solent to the south, ...

Waulsortian mudmound A Waulsortian mudmound is a calcareous geographical feature found in Early Carboniferous strata of Central Europe. It is a type of fossil-rich bioconstruction, formed by microbial activity in deep tropical waters during the mid-Dinantian (late Tour ...

: Waulsort, Namur, Belgium

References

{{reflist Stratigraphy

Examples of geological type localities

Rocks and minerals

Formations

See also

References