A volcanic plug, also called a volcanic neck or lava neck, is a

volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates a ...

object created 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 ...

hardens within a vent on an active volcano. When present, a plug can cause an extreme build-up of high gas

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and e ...

if rising volatile-charged

is trapped beneath it, and this can sometimes lead to an explosive eruption. In a plinian eruption the plug is destroyed and ash is ejected. Glacial erosion can lead to exposure of the plug on one side, while a long slope of material remains on the opposite side. Such landforms are called

crag and tail A crag (sometimes spelled cragg, or in Scotland craig) is a rocky hill or mountain, generally isolated from other high ground. Origin Crags are formed when a glacier or ice sheet passes over an area that contains a particularly resistant r ...

. If a plug is preserved,

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

may remove the surrounding rock while the erosion-resistant plug remains, producing a distinctive upstanding landform.

Examples of volcanic plugs

Africa

Near the village of

Rhumsiki Rhumsiki, also spelt Rumsiki and Roumsiki, is a village in the Far North Province of Cameroon. Rhumsiki is located in the Mandara Mountains 55 km (34 mi) from Mokolo, and is located 3 km (2 mi) from the border with Michika L ...

in the

Far North Province The Far North Region, also known as the Extreme North Region (from french: Région de l'Extrême-Nord), is the northernmost constituent province of the Republic of Cameroon. It borders the North Region to the south, Chad to the east, and Nig ...

Cameroon Cameroon (; french: Cameroun, ff, Kamerun), officially the Republic of Cameroon (french: République du Cameroun, links=no), is a country in west-central Africa. It is bordered by Nigeria to the west and north; Chad to the northeast; the C ...

, Kapsiki Peak is an example of a volcanic plug and is one of the most photographed parts of the Mandara Mountains. Spectacular volcanic plugs are present in the center of La Gomera island in the

Canary Islands The Canary Islands (; es, Canarias, ), also known informally as the Canaries, are a Spanish autonomous community and archipelago in the Atlantic Ocean, in Macaronesia. At their closest point to the African mainland, they are west of Morocc ...

archipelago, within the Garajonay National Park. Roque Bentayga visto desde Artenara

Europe

Borgarvirki Borgarvirki lies between Vesturhóp and Víðidalur in the north of Iceland, and at 177m above sea level it dominates the surrounding region. Made out of basalt strata, it has been used as a fortress. Borgarvirki is a natural phenomenon, al ...

is a volcanic plug located in north Iceland. A volcanic plug is situated in the town of Motta Sant'Anastasia in Italy. Saint Michel d'Aiguilhe chapel, whose construction started in 969, near Le Puy-en-Velay in France. The volcanic plug rises about above the surroundings. Another building on a volcanic plug is the 14th century Trosky Castle in the

Czech Republic The Czech Republic, or simply Czechia, is a landlocked country in Central Europe. Historically known as Bohemia, it is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the southeast. The ...

. Strombolicchio, the northernmost of the

Aeolian Islands The Aeolian Islands ( ; it, Isole Eolie ; scn, Ìsuli Eoli), sometimes referred to as the Lipari Islands or Lipari group ( , ) after their largest island, are a volcanic archipelago in the Tyrrhenian Sea north of Sicily, said to be named after ...

, and

Rockall Rockall () is an uninhabitable granite islet situated in the North Atlantic Ocean. The United Kingdom claims that Rockall lies within its exclusive economic zone (EEZ) and is part of its territory, but this claim is not recognised by Ireland. ...

, a small, uninhabited, remote islet in the North

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

, are also volcanic plugs. In the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

, two examples of a building on a volcanic plug are the Castle Rock in

Edinburgh Edinburgh ( ; gd, Dùn Èideann ) is the capital city of Scotland and one of its 32 Council areas of Scotland, council areas. Historically part of the county of Midlothian (interchangeably Edinburghshire before 1921), it is located in Lothian ...

, Scotland, and

Deganwy Castle Deganwy Castle ( lat-med, Arx Deganhui;'' s:la:Annales Cambriae'' (B Text), 13th century wlm, Caer Ddegannwy; Modern cy, Castell Degannwy) was an early stronghold of Gwynedd and lies in Deganwy at the mouth of the River Conwy in Conwy, north ...

Wales Wales ( cy, Cymru ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by England to the Wales–England border, east, the Irish Sea to the north and west, the Celtic Sea to the south west and the ...

. The

Law, Dundee Dundee Law is a hill in the centre of Dundee, Scotland, and is the highest point in the city. The Law is what remains of a volcanic sill, which is the result of volcanic activity around 400 million years ago. With a large war memorial at its ...

, Ailsa Craig, Bass Rock,

North Berwick Law North Berwick Law, sometimes abbreviated to Berwick Law, is a conical hill which rises conspicuously from the surrounding landscape (this is the definition of the Lowland Scots word "law"). It overlooks the East Lothian town of North Berwick, ...

and

Dumgoyne Dumgoyne is a hill prominent on the edge of the Campsie Fells and is a well-known landmark visible from Glasgow. It is a volcanic plug and is high. The plug is readily reached from a path beside Glengoyne Distillery or via a water-board track ...

hill are other examples of volcanic plugs located in

Scotland Scotland (, ) is a country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a border with England to the southeast and is otherwise surrounded by the Atlantic Ocean to the ...

. There are over 30 volcanic plugs in

Northern Ireland Northern Ireland ( ga, Tuaisceart Éireann ; sco, label= Ulster-Scots, Norlin Airlann) is a part of the United Kingdom, situated in the north-east of the island of Ireland, that is variously described as a country, province or region. Nort ...

, including Slemish in

Ballymena Ballymena ( ; from ga, an Baile Meánach , meaning 'the middle townland') is a town in County Antrim, Northern Ireland. It is part of the Borough of Mid and East Antrim. The town is built on land given to the Adair family by King Charles I i ...

Tievebulliagh Tievebulliagh () is a mountain in the Glens of Antrim, Northern Ireland. It forms part of the watershed between Glenaan to the north and Glenballyemon to the south. It is situated about 4.4 km from Cushendall. Geology Tievebulliagh is ...

, Scawt Hill, Carrickarede,

Scrabo Scrabo Tower is a high 19th-century lookout tower or folly that stands on Scrabo Hill near Newtownards in County Down, Northern Ireland. It provides wide views and is a landmark that can be seen from afar. It was built as a memorial to Charles ...

and Slieve Gallion.Wilson, H E et al (1986) Geological Survey of Northern Ireland, HMSO

North America and the Caribbean

There are several volcanic plugs in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

, including

Morro Rock Morro Rock (Salinan: ''Le'samo; ''Chumash: ''Lisamu; Spanish: ''El Morro'') is a volcanic plug in Morro Bay, California, on the Pacific Coast at the entrance to Morro Bay harbor. A causeway connects it with the shore, making it a tied is ...

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

, Devils Elbow located in the

Heceta Head Lighthouse Heceta Head Light is a lighthouse on the Oregon Coast north of Florence, and south of Yachats in the United States. It is located at Heceta Head Lighthouse State Scenic Viewpoint, a state park, midway up a 205-foot-tall (62 m) headland. Bui ...

Scenic State Park on the

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

coast, Thumb Butte in the Sierra Prieta of Arizona, and Shiprock in

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ker ...

Devils Tower Devils Tower (also known as Bear Lodge Butte) is a butte, possibly laccolithic, composed of igneous rock in the Bear Lodge Ranger District of the Black Hills, near Hulett and Sundance in Crook County, northeastern Wyoming, above the Belle F ...

Wyoming Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...

and Little Devils Postpile in

Yosemite National Park Yosemite National Park ( ) is an American national park in California, surrounded on the southeast by Sierra National Forest and on the northwest by Stanislaus National Forest. The park is managed by the National Park Service and covers an ar ...

, California, are also believed, by many

geologist A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althou ...

s, to be volcanic plugs. In

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

, the Northern Cordilleran Volcanic Province gives rise to several confirmed and suspected plugs. Chief among these is Castle Rock, located in

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

, which last erupted during the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

. The southern coast of

Saint Lucia Saint Lucia ( acf, Sent Lisi, french: Sainte-Lucie) is an island country of the West Indies in the eastern Caribbean. The island was previously called Iouanalao and later Hewanorra, names given by the native Arawaks and Caribs, two Amerindian ...

is dominated by the iconic Pitons, a

UNESCO The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations (UN) aimed at promoting world peace and security through international cooperation in education, arts, sciences and culture. It ...

World Heritage Site A World Heritage Site is a landmark or area with legal protection by an international convention administered by the United Nations Educational, Scientific and Cultural Organization (UNESCO). World Heritage Sites are designated by UNESCO for h ...

. The twin peaks, Gros Piton and Petit Piton, steeply rise more than above the

Caribbean The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean Se ...

Oceania

There are several volcanic plugs in the

North Island The North Island, also officially named Te Ika-a-Māui, is one of the two main islands of New Zealand, separated from the larger but much less populous South Island by the Cook Strait. The island's area is , making it the world's 14th-largest ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

, including: * the Pinnacles in the Coromandel Peninsula * Bream Head in Northland * Paritutu and the adjacent

Sugar Loaf Islands The Sugar Loaf Islands (often Sugarloaf; mi, Ngā Motu, ) are a collection of five small uninhabited islands and several sea stacks near Port Taranaki, New Zealand. The largest, Moturoa Island, covers approximately . Motumahanga is the island fu ...

Taranaki Taranaki is a region in the west of New Zealand's North Island. It is named after its main geographical feature, the stratovolcano of Mount Taranaki, also known as Mount Egmont. The main centre is the city of New Plymouth. The New Plymouth Dist ...

* St. Paul's Rock at Whangaroa Harbour *

Piha Piha is a coastal settlement in West Auckland, on the western coast of the Auckland Region in New Zealand. It is one of the most popular beaches in the area and a major day-trip destination for Aucklanders throughout the year, and especially ...

's Lion Rock, which hosted a fortified Maori pa. * Mount Pohaturoa near the village of Atiamuri, a distinctive sight for travelers along

State Highway 1 The following highways are numbered 1. For roads numbered A1, see list of A1 roads. For roads numbered B1, see list of B1 roads. For roads numbered M1, see List of M1 roads. For roads numbered N1, see list of N1 roads. For roads numbere ...

In New Zealand's

South Island The South Island, also officially named , is the larger of the two major islands of New Zealand in surface area, the other being the smaller but more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman ...

, Onawe Peninsula on

Banks Peninsula Banks Peninsula is a peninsula of volcanic origin on the east coast of the South Island of New Zealand. It has an area of approximately and encompasses two large harbours and many smaller bays and coves. The South Island's largest cit ...

is a prominent volcanic plug, and erosion of Saddle Hill near

Dunedin Dunedin ( ; mi, Ōtepoti) is the second-largest city in the South Island of New Zealand (after Christchurch), and the principal city of the Otago region. Its name comes from , the Scottish Gaelic name for Edinburgh, the capital of Scotland. Th ...

has also revealed a plug. Dunedin's Mount Cargill displays two plugs: its main summit and the subsidiary summit of Buttar's Peak. In

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

, The Nut in

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

are further examples, along with Mount Warning and the several peaks in the

Warrumbungles The Warrumbungles is a mountain range in the Orana region of New South Wales, Australia. The nearest town is Coonabarabran. The area is easiest accessed from the Newell Highway which is the major road link directly between Melbourne, Victoria ...

in New South Wales. The 11 peaks of the Glasshouse Mountains National Park including

Mount Beerwah Mount Beerwah is the highest of the ten volcanic plugs in the Glass House Mountains range, 22 km north of Caboolture in South East Queensland, Australia. It was formed 26 million years ago during the Oligocene Epoch of the Paleogene Period. ...

Mount Tibrogargan Mount Tibrogargan is a small mountain in the Glass House Mountains National Park, north-northwest of Brisbane, Australia. It is a magma intrusion of hard alkali rhyolite that squeezed up into the vents of an ancient volcano 27 million years ago. ...

Mount Coonowrin Coonowrin is one of the Glass House Mountains, located in Queensland, Australia, located 19 km north of Caboolture or about one hour's drive north of Brisbane. It is easily distinguished because of its rocky formation at the top. It is als ...

Mount Ngungun Mount Ngun Ngun (said as Ngun Ngun) is the sixth tallest of the Glass House Mountains at 253 m. It has a well maintained walking trail to the summit that affords good views. The trail from carpark (with tap) is not as steep as the higher mo ...

, Mount Tibberoowuccum, Mount Tunbubudla, and Mount Beerburrum, in South East Queensland are volcanic plugs.

Gallery

Edinburgh Castle From Princes Street Garden 001.jpg,

Edinburgh Castle Edinburgh Castle is a historic castle in Edinburgh, Edinburgh, Scotland. It stands on Castle Rock (Edinburgh), Castle Rock, which has been occupied by humans since at least the Iron Age, although the nature of the early settlement is unclear. ...

is built upon an ancient volcanic plug. Mt Popa.jpg,

Taung Kalat Taung Kalat ( my, ပုပ္ပါးတောင်ကလပ်) is a Buddhist monastery and temple complex located on Mount Popa in Mandalay Region, Myanmar. The site is built on a tall volcanic plug, and is one of several prominent ''Nat (spir ...

, Burma. Strombolicchio2.jpg, Strombolicchio Island and its lighthouse, close to Stromboli Island (

, Italy). RoqueNublo2.jpg,

Roque Nublo Roque Nublo (''Clouded Rock'', ''Rock in the Clouds'') is a volcanic rock on the island of Gran Canaria, Canary Islands, Spain. It is tall, and its top is above sea level. The Roque Nublo is the third altitude of the island of Gran Canaria, aft ...

, symbol of Gran Canaria island. Slemish (8) - geograph.org.uk - 834986.jpg, Slemish, a volcanic plug in

, is traditionally associated with

St Patrick Saint Patrick ( la, Patricius; ga, Pádraig ; cy, Padrig) was a fifth-century Romano-British Christian missionary and bishop in Ireland. Known as the "Apostle of Ireland", he is the primary patron saint of Ireland, the other patron saints be ...

. TroskyCastle.JPG, Trosky Castle ("Panna" Tower), Czech Republic. Devils_Tower.jpg,

, Wyoming, USA. File:Shiprock.snodgrass3.jpg, Shiprock, New Mexico, USA. File:Whangaroa_Harbour3.JPG, St. Paul's Rock, above Whangaroa Harbour, Northland, New Zealand. São Tomé - Pico Cão Grande.jpg,

Pico Cão Grande The Pico Cão Grande (Portuguese for "Great Dog Peak") is a landmark needle-shaped volcanic plug peak in São Tomé and Príncipe, in the Caué District of São Tomé Island in Parque Natural Obô de São Tomé. Its summit is above sea level, and ...

, landmark volcanic plug peak on São Tomé Island (São Tomé and Príncipe), rising over above the surroundings. Dent_de_la_Rancune,_voie_normale.png, Dent de la Rancune, a challenging climbing site in the

Chaîne des Puys The Chaîne des Puys () is a north-south oriented chain of cinder cones, lava domes, and maars in the Massif Central of France. The chain is about 40 km (25 mi) long, and the identified volcanic features, which constitute a volcanic fie ...

, France. File:Crater Bluff Warrumbungles.jpg, Crater Bluff in the

, New South Wales

References

{{Earth's landforms Volcanic landforms