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

volcanic A volcano is commonly defined as a vent or fissure 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 fo ...

object created when

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma (sometimes colloquially but incorrectly referred to as ''lava'') is found beneath the surface of the Earth, and evidence of magmatism has also ...

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 eve ...

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 A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

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. If a plug is preserved,

erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...

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 in the

Far North Province The Far North Region, also known as the Extreme North Region (from ), is the northernmost and most populous constituent province of Cameroon, the Republic of Cameroon. It borders the North Region (Cameroon), North Region to the south, Chad to ...

Cameroon Cameroon, officially the Republic of Cameroon, is a country in Central Africa. It shares boundaries with Nigeria to the west and north, Chad to the northeast, the Central African Republic to the east, and Equatorial Guinea, Gabon, and the R ...

, 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 La Gomera () is one of Spain's Canary Islands, in the Atlantic Ocean off the coast of Africa. With an area of , it is the third-smallest of the archipelago's eight main islands. It belongs to the province of Santa Cruz de Tenerife. La Gomer ...

island in the

Canary Islands The Canary Islands (; ) or Canaries are an archipelago in the Atlantic Ocean and the southernmost Autonomous communities of Spain, Autonomous Community of Spain. They are located in the northwest of Africa, with the closest point to the cont ...

archipelago, within the

Garajonay National Park Garajonay National Park (, ) is located in the center and north of the island of La Gomera, one of the Canary Islands (Spain). It was declared a national park in 1981 and a World Heritage Site by UNESCO in 1986. It occupies 40 km2 (15 sq m ...

. 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 663 m (2,175 ft) above sea level, and it rises about 370 m (1,210 ft) over the surrounding terrain. Roque Bentayga visto desde Artenara

Asia

Sigiriya is an ancient rock fortress near the town of Dambulla in

Sri Lanka Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, also known historically as Ceylon, is an island country in South Asia. It lies in the Indian Ocean, southwest of the Bay of Bengal, separated from the Indian subcontinent, ...

. Approximately 180m high, it is now a UNESCO listed

World Heritage Site World Heritage Sites are landmarks and areas with legal protection under an treaty, international treaty administered by UNESCO for having cultural, historical, or scientific significance. The sites are judged to contain "cultural and natural ...

Europe

Borgarvirki 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 Le Puy-en-Velay (, ; , before 1988: ''Le Puy'') is the Prefectures in France, prefecture of the Haute-Loire Departments of France, department in the Auvergne-Rhône-Alpes Regions of France, region of south-central France. Located near the rive ...

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, also known as Czechia, and historically known as Bohemia, is a landlocked country in Central Europe. The country is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the south ...

. Strombolicchio, the northernmost of the

Aeolian Islands The Aeolian Islands ( ; ; ), 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 Aeolus, the mythical ruler of ...

, and Rockall, a small, uninhabited, remote

islet An islet ( ) is generally a small island. Definitions vary, and are not precise, but some suggest that an islet is a very small, often unnamed, island with little or no vegetation to support human habitation. It may be made of rock, sand and/ ...

in the North

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

, 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 Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

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

Edinburgh Edinburgh is the capital city of Scotland and one of its 32 Council areas of Scotland, council areas. The city is located in southeast Scotland and is bounded to the north by the Firth of Forth and to the south by the Pentland Hills. Edinburgh ...

, Scotland, and Deganwy Castle,

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

. The Law, Dundee, Ailsa Craig, Bass Rock, North Berwick Law and Dumgoyne hill are other examples of volcanic plugs located in

Scotland Scotland is a Countries of the United Kingdom, country that is part of the United Kingdom. It contains nearly one-third of the United Kingdom's land area, consisting of the northern part of the island of Great Britain and more than 790 adjac ...

. There are over 30 volcanic plugs in

Northern Ireland Northern Ireland ( ; ) is a Countries of the United Kingdom, part of the United Kingdom in the north-east of the island of Ireland. It has been #Descriptions, variously described as a country, province or region. Northern Ireland shares Repub ...

, including Slemish in

Ballymena Ballymena ( ; from , meaning 'the middle townland') is a town in County Antrim, Northern Ireland. It had a population of 31,205 people at the 2021 United Kingdom census, making it the List of localities in Northern Ireland by population, seven ...

, Tievebulliagh, Scawt Hill, Carrickarede, Scrabo and

Slieve Gallion Slieve Gallion () is a mountain in County Londonderry, Northern Ireland. It is the easternmost of the Sperrin Mountains. It reaches a height of and dominates the western shore of Lough Neagh. Its prominent northeastern summit has a transm ...

.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 (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, including Morro Rock in

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

, Devils Elbow located in the Heceta Head Lighthouse Scenic State Park on the

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

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

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

. Devils Tower in

Wyoming Wyoming ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States, Western United States. It borders Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho t ...

and Little Devils Postpile in

Yosemite National Park Yosemite National Park ( ) is a List of national parks of the United States, national park of the United States in California. It is bordered on the southeast by Sierra National Forest and on the northwest by Stanislaus National Forest. The p ...

, California, are also believed, by many

geologist A geologist is a scientist who studies the structure, composition, and History of Earth, history of Earth. Geologists incorporate techniques from physics, chemistry, biology, mathematics, and geography to perform research in the Field research, ...

s, to be volcanic plugs. In Canada, 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 is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

, which last erupted during the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

. The southern coast of

Saint Lucia Saint Lucia is an island country of the West Indies in the eastern Caribbean. Part of the Windward Islands of the Lesser Antilles, it is located north/northeast of the island of Saint Vincent (Saint Vincent and the Grenadines), Saint Vincent ...

is dominated by the iconic Pitons, a

UNESCO The United Nations Educational, Scientific and Cultural Organization (UNESCO ) is a List of specialized agencies of the United Nations, specialized agency of the United Nations (UN) with the aim of promoting world peace and International secur ...

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

Caribbean The Caribbean ( , ; ; ; ) is a region in the middle of the Americas centered around the Caribbean Sea in the Atlantic Ocean, North Atlantic Ocean, mostly overlapping with the West Indies. Bordered by North America to the north, Central America ...

South America

Pinnacle Rock, Galápagos, Ecuador.

Oceania

There are several volcanic plugs in the

North Island The North Island ( , 'the fish of Māui', historically New Ulster) is one of the two main islands of New Zealand, islands of New Zealand, separated from the larger but less populous South Island by Cook Strait. With an area of , it is the List ...

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

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

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

* St. Paul's Rock at Whangaroa Harbour * Piha's Lion Rock, which hosted a fortified Maori

pā The word pā (; often spelled pa in English) can refer to any Māori people, Māori village or defensive settlement, but often refers to hillforts – fortified settlements with palisades and defensive :wikt:terrace, terraces – and also to fo ...

* Mount Pohaturoa near the village of Ātiamuri, a distinctive sight for travelers along State Highway 1 In New Zealand's

South Island The South Island ( , 'the waters of Pounamu, Greenstone') is the largest of the three major islands of New Zealand by surface area, the others being the smaller but more populous North Island and Stewart Island. It is bordered to the north by ...

, Onawe Peninsula on Banks Peninsula is a prominent volcanic plug, and erosion of Saddle Hill near

Dunedin Dunedin ( ; ) is the second-most populous city in the South Island of New Zealand (after Christchurch), and the principal city of the Otago region. Its name comes from ("fort of Edin"), the Scottish Gaelic name for Edinburgh, the capital of S ...

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 country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

, The Nut in

Tasmania Tasmania (; palawa kani: ''Lutruwita'') is an island States and territories of Australia, state of Australia. It is located to the south of the Mainland Australia, Australian mainland, and is separated from it by the Bass Strait. The sta ...

are further examples, along with Mount Warning and the several peaks in the Warrumbungles in New South Wales. The 11 peaks of the Glasshouse Mountains National Park including Mount Beerwah, Mount Tibrogargan, Mount Coonowrin, Mount Cooroora, Mount Ngungun, Mount Tibberoowuccum, Mount Tunbubudla, and Mount Beerburrum, in

South East Queensland South East Queensland (SEQ) is a Bioregion, bio-geographical, Megalopolis, metropolitan and Statistics, statistical Regions of Queensland, region of the States and territories of Australia, state of Queensland in Australia, with a population of ...

are volcanic plugs.

Gallery

Edinburgh Castle From Princes Street Garden 001.jpg,

Edinburgh Castle Edinburgh Castle is a historic castle in Edinburgh, Scotland. It stands on Castle Rock (Edinburgh), Castle Rock, which has been occupied by humans since at least the Iron Age. There has been a royal castle on the rock since the reign of Malcol ...

is built upon an ancient volcanic plug. Mt Popa.jpg, Taung Kalat, Burma. Strombolicchio2.jpg, Strombolicchio Island and its lighthouse, close to Stromboli Island (

, Italy). RoqueNublo2.jpg, Roque Nublo, symbol of

Gran Canaria Gran Canaria (, ; ), also Grand Canary Island, is the third-largest and second-most-populous island of the Canary Islands, a Spain, Spanish archipelago off the Atlantic coast of Northwest Africa. the island had a population of that constitut ...

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

, is traditionally associated with St Patrick. TroskyCastle.JPG, Trosky Castle ("Panna" Tower), Czech Republic. Devils_Tower.jpg, Devils Tower, 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, landmark volcanic plug peak on

São Tomé Island São Tomé Island, at , is the largest island of São Tomé and Príncipe and is home in May 2018 to about 193,380 or 96% of the nation's population. The island is divided into six districts of São Tomé and Príncipe, districts. It is located ...

(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, France. File:Crater Bluff Warrumbungles.jpg, Crater Bluff in the Warrumbungles, New South Wales

References

{{Earth's landforms Volcanic landforms