In marine geology, a guyot, also known as a tablemount, is an isolated underwater volcanic mountain (seamount) with a flat top more than 200 m (660 ft) below the surface of the sea. The diameters of these flat summits can exceed 10 km (6.2 mi). Guyots are most commonly found in the Pacific Ocean, but they have been identified in all the oceans except the Arctic Ocean.
The fifteen volcanoes that make up the eight principal islands of Hawaii are the youngest in a chain of more than 129 volcanoes that stretch 5,800 kilometres (3,600 mi) across the North Pacific Ocean, called the Hawaiian–Emperor seamount chain. Hawaiʻi's volcanoes rise an average of 4,600 metres (15,000 ft) to reach sea level from their base. The largest, Mauna Loa, is 4,169 metres (13,678 ft) high. As shield volcanoes, they are built by accumulated lava flows, growing a few meters or feet at a time to form a broad and gently sloping shape.
In geology, the places known as hotspots or hot spots are volcanic regions 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.
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 Bowie hotspot is a volcanic hotspot, located 180 kilometres (110 mi) west of the Queen Charlotte Islands in the Pacific Ocean.
Bowie Seamount is a large submarine volcano in the northeastern Pacific Ocean, located 180 km (110 mi) west of Haida Gwaii, British Columbia, Canada.
The Tuzo Wilson Seamounts, also called J. Tuzo Wilson Knolls and Tuzo Wilson Knolls, are two young active submarine volcanoes off the coast of British Columbia, Canada, located 200 km (124 mi) northwest of Vancouver Island and south of the Haida Gwaii archipelago The two seamounts are members of the Kodiak-Bowie Seamount chain, rising 500 m (1,640 ft) to 700 m (2,297 ft) above the mean level of the northeastern Pacific Ocean and is a seismically active site southwest of the southern end of the Queen Charlotte Fault. They are named after Canadian geologist John Tuzo Wilson.
The Easter hotspot is a volcanic hotspot located in the southeastern Pacific Ocean. The hotspot created the Sala y Gómez Ridge which includes Easter Island and the Pukao Seamount which is at the ridge's young western edge. Easter Island, because of its tectonomagmatic features, represents an end-member type of hotspot volcano in this chain.
The Cobb-Eickelberg seamount chain is a range of undersea mountains formed by volcanic activity of the Cobb hotspot located in the Pacific Ocean. The seamount chain extends to the southeast on the Pacific Plate, beginning at the Aleutian Trench and terminating at Axial Seamount, located on the Juan de Fuca Ridge.The seamount chain is spread over a vast length of approximately 1800 km. The location of the Cobb hotspot that gives rise to these seamounts is 46° N -130° W. The Pacific plate is moving to the northwest over the hotspot, causing the seamounts in the chain to decrease in age to the southeast. Axial is the youngest seamount and is located approximately 480 km west of Cannon Beach, Oregon. The most studied seamounts that make up this chain are Axial, Brown Bear, Cobb, and Patton seamounts. There are many other seamounts in this chain which have not been explored.
The Hawai’i hotspot is a volcanic hotspot located near the namesake Hawaiian Islands, in the northern Pacific Ocean. One of the best known and intensively studied hotspots in the world, the Hawaii plume is responsible for the creation of the Hawaiian–Emperor seamount chain, a 6,200-kilometer (3,900 mi) mostly undersea volcanic mountain range. Four of these volcanoes are active, two are dormant; more than 123 are extinct, most now preserved as atolls or seamounts. The chain extends from south of the island of Hawaiʻi to the edge of the Aleutian Trench, near the eastern coast of Russia.
Hodgkins Seamount is a seamount in the Kodiak-Bowie Seamount chain, located south of Pierce Seamount and north of Bowie Seamount. It has apparently experienced two generically different episodes of volcanism, separated by about 12 million years. Like the rest of the Kodiak-Bowie seamounts, it was formed by the Bowie hotspot.
Peirce Seamount, also called Pierce Seamount, is a seamount located in the Pacific Ocean west of the Queen Charlotte Islands, British Columbia, Canada. It lies between Denson Seamount and Hodgkins Seamount and is member of the Kodiak-Bowie Seamount chain, a chain of seamounts in southeastern Gulf of Alaska stretching from the Aleutian Trench in the north to Bowie Seamount in the south.
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 Fogo Seamounts, also called the Fogo Seamount Chain, are a group of undersea mountains southeast of the Grand Banks of Newfoundland in the North Atlantic Ocean. This seamount chain, lying approximately 500 km (310 mi) offshore from the island of Newfoundland, consists of several submarine volcanoes that have been extinct for millions of years. They are one of the few seamount chains located in Canadian waters off the coast of Atlantic Canada.
The Newfoundland Seamounts are a group of seamounts offshore of Eastern Canada in the northern Atlantic Ocean. Named for the island of Newfoundland, this group of seamounts formed during the Cretaceous period and are poorly studied.
The volcanology of Eastern Canada includes the hundreds of volcanic areas and extensive lava formations in Eastern Canada. The region's different volcano and lava types originate from different tectonic settings and types of volcanic eruptions, ranging from passive lava eruptions to violent explosive eruptions. Eastern Canada has very large volumes of magmatic rock called large igneous provinces. They are represented by deep-level plumbing systems consisting of giant dike swarms, sill provinces and layered intrusions. The most capable large igneous provinces in Eastern Canada are Archean age greenstone belts containing a rare volcanic rock called komatiite.
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.
Undersea mountain ranges are mountain ranges that are mostly or entirely underwater, and specifically under the surface of an ocean. If originated from current tectonic forces, they are often referred to as a mid-ocean ridge. In contrast, if formed by past above-water volcanism, they are known as a seamount chain. The largest and best known undersea mountain range is a mid-ocean ridge, the Mid-Atlantic Ridge. It has been observed that, "similar to those on land, the undersea mountain ranges are the loci of frequent volcanic and earthquake activity".
The Tasmantid hotspot is a volcanic hotspot located in the South Pacific Ocean. Due to plate tectonics the hotspot was under different parts of the seabed in the past. It was initially centered under what is now the southern Coral Sea 60 million years ago where the first Tasmantid volcano was created. As the Indo-Australian Plate continued to drift northwards the hotspot was positioned in the northern Tasman Sea 20 million years ago, eventually reaching its current location east of Tasmania in response to ongoing northward plate motion.
