 | This articleneeds additional citations forverification. Please helpimprove this article byadding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Volcanic plug" – news ·newspapers ·books ·scholar ·JSTOR(June 2013) (Learn how and when to remove this message) |
Avolcanic plug, also called avolcanic neck orlava neck, is avolcanic object created whenmagma hardens within avent on an active volcano. When present, a plug can cause an extreme build-up of high gaspressure if risingvolatile-chargedmagma is trapped beneath it, and this can sometimes lead to an explosive eruption. In aplinian eruption the plug is destroyed and ash is ejected.[1]
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 calledcrag and tail. If a plug is preserved,erosion may remove the surrounding rock while the erosion-resistant plug remains, producing a distinctive upstanding landform.
Near the village ofRhumsiki in theFar North Province ofCameroon, Kapsiki Peak is an example of a volcanic plug and is one of the most photographed parts of theMandara Mountains. Spectacular volcanic plugs are present in the center ofLa Gomera island in theCanary Islands archipelago, within theGarajonay National Park.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,[1] and it rises about 370 m (1,210 ft) over the surrounding terrain.[2]
Sigiriya is an ancient rock fortress near the town ofDambulla inSri Lanka. Approximately 180m high, it is now a UNESCO listedWorld Heritage Site.[2]
Borgarvirki is a volcanic plug located in north Iceland.
A volcanic plug is situated in the town ofMotta Sant'Anastasia in Italy.
Saint Michel d'Aiguilhe chapel, whose construction started in 969,[3] nearLe Puy-en-Velay in France. The volcanic plug rises about 85 metres (279 ft) above the surroundings. Another building on a volcanic plug is the 14th centuryTrosky Castle in theCzech Republic.Strombolicchio, the northernmost of theAeolian Islands, andRockall, a small, uninhabited, remoteislet in the NorthAtlantic Ocean, are also volcanic plugs.
In theUnited Kingdom, two examples of a building on a volcanic plug are theCastle Rock inEdinburgh, Scotland, andDeganwy Castle,Wales. TheLaw, Dundee,Ailsa Craig,Bass Rock,North Berwick Law andDumgoyne hill are other examples of volcanic plugs located inScotland. There are over 30 volcanic plugs inNorthern Ireland, includingSlemish inBallymena,Tievebulliagh,Scawt Hill,Carrickarede,Scrabo andSlieve Gallion.[4]
There are several volcanic plugs in theUnited States, includingMorro Rock inCalifornia, Devils Elbow located in theHeceta Head Lighthouse Scenic State Park on theOregon coast, Thumb Butte in theSierra Prieta of Arizona and Agathla Peak nearMonument Valley, andShiprock inNew Mexico.Devils Tower inWyoming andLittle Devils Postpile inYosemite National Park, California, are also believed, by manygeologists, to be volcanic plugs. In Canada, theNorthern Cordilleran Volcanic Province gives rise to several confirmed and suspected plugs. Chief among these isCastle Rock, located inBritish Columbia, which last erupted during thePleistocene. The southern coast ofSaint Lucia is dominated by the iconicPitons, aUNESCOWorld Heritage Site. The twin peaks, Gros Piton and Petit Piton, steeply rise more than 770 metres (2,530 ft) above theCaribbean.
Pinnacle Rock, Galápagos, Ecuador.
There are several volcanic plugs in theNorth Island ofNew Zealand, including:
In New Zealand'sSouth Island,Onawe Peninsula onBanks Peninsula is a prominent volcanic plug, and erosion ofSaddle Hill nearDunedin has also revealed a plug. Dunedin'sMount Cargill displays two plugs: its main summit and the subsidiary summit of Buttar's Peak.
InAustralia,The Nut inTasmania are further examples, along withMount Warning and the several peaks in theWarrumbungles in New South Wales. The 11 peaks of theGlasshouse Mountains National Park includingMount Beerwah,Mount Tibrogargan,Mount Coonowrin,Mount Cooroora,Mount Ngungun, Mount Tibberoowuccum, Mount Tunbubudla, and Mount Beerburrum, inSouth East Queensland are volcanic plugs.[5][6]
_-_geograph.org.uk_-_834986.jpg)
