A mantle plume is a proposed mechanism of convection within the Earth's mantle, hypothesized to explain anomalous volcanism. Because the plume head partially melts on reaching shallow depths, a plume is often invoked as the cause of volcanic hotspots, such as Hawaii or Iceland, and large igneous provinces such as the Deccan and Siberian Traps. Some such volcanic regions lie far from tectonic plate boundaries, while others represent unusually large-volume volcanism near plate boundaries.
In geology, hotspots are volcanic locales thought to be fed by underlying mantle that is anomalously hot compared with the surrounding mantle. Examples include the Hawaii, Iceland, and Yellowstone hotspots. A hotspot's position on the Earth's surface is independent of tectonic plate boundaries, and so hotspots may create a chain of volcanoes as the plates move above them.
A large igneous province (LIP) is an extremely large accumulation of igneous rocks, including intrusive and extrusive, arising when magma travels through the crust towards the surface. The formation of LIPs is variously attributed to mantle plumes or to processes associated with divergent plate tectonics. The formation of some of the LIPs in the past 500 million years coincide in time with mass extinctions and rapid climatic changes, which has led to numerous hypotheses about causal relationships. LIPs are fundamentally different from any other currently active volcanoes or volcanic systems.
The Iceland hotspot is a hotspot which is partly responsible for the high volcanic activity which has formed the Iceland Plateau and the island of Iceland.
The East Australia hotspot is a volcanic province in southeast Australia which includes the Peak Range in central Queensland, the Main Range on the Queensland-New South Wales border, Tweed Volcano in New South Wales, and the Newer Volcanics Province (NVP) in Victoria and South Australia. A number of the volcanoes in the province have erupted since Aboriginal settlement. The most recent eruptions were about 5,600 years ago, and memories of them survive in Aboriginal folklore. These eruptions formed the volcanoes Mount Schank and Mount Gambier in the NVP. There have been no eruptions on the Australian mainland since European settlement.
The New England hotspot, also referred to as the Great Meteor hotspot and sometimes the Monteregian hotspot, is a volcanic hotspot in the North Atlantic Ocean. It created the Monteregian Hills intrusions in Montreal and Montérégie, the White Mountains intrusions in New Hampshire, the New England and Corner Rise seamounts off the coast of North America, and the Seewarte Seamounts east of the Mid-Atlantic Ridge on the African Plate, the latter of which include its most recent eruptive center, the Great Meteor Seamount. The New England, Great Meteor, or Monteregian hotspot track has been used to estimate the movement of the North American Plate away from the African Plate from the early Cretaceous period to the present using the fixed hotspot reference frame.
The Eifel hotspot is a volcanic hotspot in Western Germany. It is one of many recent volcanic formations in and around the Eifel mountain range and includes the volcanic field known as Volcanic Eifel. Although the last eruption occurred around 10,000 years ago, the presence of escaping volcanic gases in the region indicates that it is still weakly active.
The Marquesas hotspot is a volcanic hotspot in the southern Pacific Ocean. It is responsible for the creation of the Marquesas Islands – a group of eight main islands and several smaller ones – and a few seamounts. The islands and seamounts formed between 5.5 and 0.4 million years ago and constitute the northernmost volcanic chain in French Polynesia.
The Macdonald hotspot is a volcanic hotspot in the southern Pacific Ocean. The hotspot was responsible for the formation of the Macdonald Seamount, and possibly the Austral-Cook Islands chain. It probably did not generate all of the volcanism in the Austral and Cook Islands as age data imply that several additional hotspots were needed to generate some volcanoes.
Ocean island basalt (OIB) is a volcanic rock, usually basaltic in composition, erupted in oceans away from tectonic plate boundaries. Although ocean island basaltic magma is mainly erupted as basalt lava, the basaltic magma is sometimes modified by igneous differentiation to produce a range of other volcanic rock types, for example, rhyolite in Iceland, and phonolite and trachyte at the intraplate volcano Fernando de Noronha. Unlike mid-ocean ridge basalts (MORBs), which erupt at spreading centers (divergent plate boundaries), and volcanic arc lavas, which erupt at subduction zones (convergent plate boundaries), ocean island basalts are the result of intraplate volcanism. However, some ocean island basalt locations coincide with plate boundaries like Iceland, which sits on top of a mid-ocean ridge, and Samoa, which is located near a subduction zone.
Cape Verde is a volcanic archipelago situated above an oceanic rise that puts the base of the islands 2 kilometers (1.2 mi) above the rest of the seafloor. Cape Verde has been identified as a hotspot and the majority of geoscientists have argued that the archipelago is underlain by a mantle plume and that this plume is responsible for the volcanic activity and associated geothermal anomalies.
Kunlun Volcanic Group, also known as Ashikule Volcanic Field, is a volcanic field in northwestern Tibet. Eight other volcanic fields are also in the area. The field is within a basin that also contains three lakes.
Arago hotspot is a hotspot in the Pacific Ocean, presently located below the Arago seamount close to the island of Rurutu, French Polynesia.
Cerro de los Chenques is a monogenetic volcano in the Chubut Province, Argentina, which was considered to be of Holocene age but was later re-dated to be of lower Pleistocene age. The volcano developed on a basement formed by Mesoproterozoic and Neoproterozoic rocks and more recent volcanic and granitic formations.
The Discovery Seamounts are a chain of seamounts in the Southern Atlantic Ocean, including Discovery Seamount. The seamounts are 850 kilometres (530 mi) east of Gough Island and once formed islands. Various volcanic rocks as well as glacial dropstones and sediments have been dredged from the Discovery Sseamounts.
Gharyan volcanic field is a volcanic field in northwestern Libya, with the towns of Bani Walid, Gharyan, Mizdah and Tarhunah close by.
The Rarotonga hotspot is a volcanic hotspot in the southern Pacific Ocean. The hotspot is claimed to be responsible for the formation of Rarotonga and some volcanics of Aitutaki but an alternative explanation for these islands most recent volcanics has not been ruled out. Recently alternatives to hotspot activity have been offered for several other intra-plate volcanoes that may have been associated with the Rarotonga hotspot hypothesis.
South Arch volcanic field is an underwater volcanic field south of Hawaiʻi Island. It was active during the last 10,000 years, and covers an area of 35 by 50 kilometres at a depth of 4,950 metres (16,240 ft).
North Arch volcanic field is an underwater volcanic field north of Oahu, Hawaii. It covers an area of about 25,000 square kilometres (9,700 sq mi) and consists of large expanses of alkali basalt, basanite and nephelinite that form extensive lava flows and volcanic cones. Some lava flows are longer than 100 kilometres (62 mi).
Intraplate volcanism is volcanism that takes place away from the margins of tectonic plates. Most volcanic activity takes place on plate margins, and there is broad consensus among geologists that this activity is explained well by the theory of plate tectonics. However, the origins of volcanic activity within plates remains controversial.
