A seamount is a large geologic landform that rises from the ocean floor but that does not reach to the water's surface (sea level), and thus is not an island, islet or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abruptly and are usually found rising from the seafloor to in height. They are defined by oceanographers as independent features that rise to at least above the seafloor, characteristically of conical form. The peaks are often found hundreds to thousands of meters below the surface, and are therefore considered to be within the deep sea. During their evolution over geologic time, the largest seamounts may reach the sea surface where wave action erodes the summit to form a flat surface.
Introduction
Seamount
Seamount | Introduction
Seamount A seamount Seamount Seamount.
what is a chain of underwater mountains called
user
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".
Undersea mountain range | Introduction
Seamount – A mountain rising from the ocean seafloor that does not reach to the water's surface
Outline of oceanography | Seamounts
Lamont seamount chain is a chain of submarine mountains in the eastern Pacific Ocean which are named "Sasha", "MIB", "MOK", "DTD" and "NEW". They are located close to the East Pacific Rise and reach a minimum depth of . These seamounts are submarine volcanoes of Pleistocene to Holocene age that are usually capped off by summit calderas and craters. They have erupted lava flows of tholeiitic composition; the last eruption may have occurred less than 8,000 years ago.
Lamont seamount chain | Introduction
A seamount is a large geologic landform that rises from the ocean floor but that does not reach to the water's surface (sea level), and thus is not an island, islet or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abruptly and are usually found rising from the seafloor to in height. They are defined by oceanographers as independent features that rise to at least above the seafloor, characteristically of conical form. The peaks are often found hundreds to thousands of meters below the surface, and are therefore considered to be within the deep sea. During their evolution over geologic time, the largest seamounts may reach the sea surface where wave action erodes the summit to form a flat surface.
Seamount | Introduction
A number of flat-topped seamounts rise from the floor of the western Pacific Ocean to depths of below sea level. They are called guyots and are clustered in an elongated region with and between the Marshall Islands and the Tuamotus. It is presumed that hotspots generated most of these seamounts. The Marshall Islands are grouped in two chains and three groups, the Ratak Chain including Limalok Guyot, the Ralik Chain including Wōdejebato Guyot and an isolated cluster farther west including Eniwetok Island.
Ruwitūn̄tūn̄ | Geological context
The New England Seamounts is a chain of over twenty underwater extinct volcanic mountains known as seamounts. This chain is located off the coast of Massachusetts in the Atlantic Ocean and extends over 1,000 km from the edge of Georges Bank. Many of the peaks of these mountains rise over 4,000 m from the seabed. The New England Seamounts chain is the longest such chain in the North Atlantic and is home to a diverse range of deep sea fauna. Scientists have visited the chain on various occasions to survey the geologic makeup and biota of the region. The chain is part of the Great Meteor hotspot track and was formed by the movement of the North American Plate over the New England hotspot.
New England Seamounts | Introduction
The Hawaiian–Emperor seamount chain is a mostly undersea mountain range in the Pacific Ocean that reaches above sea level in Hawaii. It is composed of the Hawaiian ridge, consisting of the islands of the Hawaiian chain northwest to Kure Atoll, and the Emperor Seamounts: together they form a vast underwater mountain region of islands and intervening seamounts, atolls, shallows, banks and reefs along a line trending southeast to northwest beneath the northern Pacific Ocean. The seamount chain, containing over 80 identified undersea volcanoes, stretches about from the Aleutian Trench in the far northwest Pacific to the Loʻihi seamount, the youngest volcano in the chain, which lies about southeast of the Island of Hawaiʻi.
Hawaiian–Emperor seamount chain | Introduction
This is a list of Seamounts in the Southern Ocean. A seamount is a mountain rising from the ocean seafloor that does not reach to the water's surface (sea level), and thus is not an island, islet or Cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abruptly and are usually found rising from the seafloor to in height. They are defined by oceanographers as independent features that rise to at least above the seafloor, characteristically of conical form.
List of seamounts in the Southern Ocean | Introduction
The shallowest part of the chain is on one of the western seamounts and lies at depth while Sasha reaches to , "MIB" to depth, "MOK" to and "NEW" to ; in general the seamounts shallow westward and their outline changes from conical to more elongated.
Lamont seamount chain | Geography and geomorphology
Seamounts can be found in every ocean basin in the world, distributed extremely widely both in space and in age. A seamount is technically defined as an isolated rise in elevation of or more from the surrounding seafloor, and with a limited summit area, of conical form. There are more than 14,500 seamounts. In addition to seamounts, there are more than 80,000 small knolls, ridges and hills less than 1,000 m in height in the world's oceans. Most seamounts are volcanic in origin, and thus tend to be found on oceanic crust near mid-ocean ridges, mantle plumes, and island arcs.
Seamount | Geography
A further sampling cruise by the United States Geological Survey (USGS) recovered pillow lava and hyaloclastite from 4 of the 8 volcanoes. The samples seemed to be of more primitive origin then those erupted elsewhere on the ridge. In 1998, the Monterey Bay Aquarium Research Institute conducted two dives on a cone cluster located southeast of the main structure. The chain consists of eight volcanoes. Of these, four are self-dependent, whereas the other four form twin fused, morphalogically complex, flat-topped structures. The volcanoes form a linear chain, and are relatively small, measuring less than in diameter, and are nearly circular in shape.
President Jackson Seamounts | Introduction
Otherwise, seamounts tend not to form distinctive chains in the Indian and Southern Oceans, but rather their distribution appears to be more or less random. Isolated seamounts and those without clear volcanic origins are less common; examples include Bollons Seamount, Eratosthenes Seamount, Axial Seamount and Gorringe Ridge.
Seamount | Grouping
The seamount lies in the Mid-Pacific Mountains on their southern side and is a submarine mountain with a flat top that rises over to a depth of -. The flat top has an oval shape and a surface area of ; it is characterized by a limestone dome on the summit, buried beneath sediments; in turn a volcanic hill is buried within the limestone dome. The top of the seamount has a hummocky appearance which has been interpreted as a sediment cover and its southeastern sector has a bank-like shape that resembles that of an atoll. Cape Johnson Guyot is considered to be of Middle Cretaceous age with an age of 120 million years reported and shallow-water fossils were emplaced on it at that time.
Cape Johnson Guyot | Geography and geology
The Foundation chain eventually becomes a set of three ridges close to the Pacific-Antarctic Ridge, the northern two of which are the more voluminous ones. These northern ridges are probably the main ones; the southern one may have formed through cracks in the crust induced by the northern ridge, but it might also be a "paired" expression of a hotspot similar to the Kea and Loa trends in Hawaii. The seamounts reach depths of beneath sea level (the highest seamount is located at ), and contain typical volcanic features such as smaller volcanic cones, calderas and individual rift zones. Some of the seamounts close to the ridge have flat tops and show evidence of having formed islands above sea level in the past.
Foundation Seamounts | Geography
These tops must be or more below the surface of the sea; the diameters of these flat summits can be over . Knolls are isolated elevation spikes measuring less than . Lastly, pinnacles are small pillar-like seamounts.
Seamount | Structure
Hebrides Terrace Seamount is a seamount in the Atlantic Ocean, west-southwest from the Hebrides, Scotland. It formed through volcanism during the early Cenozoic in the Rockall Trough 60 million to 67 million years ago and afterwards sank below sea level. Presently, it is a flat-topped underwater mountain that rises to about 980 metres (3,220 ft) depth. "Coral gardens" that host a number of animals are found on its slopes.
Hebrides Terrace Seamount | Introduction
The Lamont seamount chain is a group of five seamounts in the Pacific Ocean; from southeast to northwest they are known as "Sasha", "MIB", "MOK", "DTD" and "NEW" and there is an additional unnamed seamount southwest from "NEW". The seamounts were discovered in 1983 and named later. The seamounts reach heights of and have summit craters/calderas, that on "DTD", "MOK" and "NEW" form nested, complex calderas. Horseshoe-shaped volcanic ridges accompany the calderas and lava effusion appears to have preferentially occurred on the margins of the calderas, along with mass wasting. The Lamont seamount chain forms a long chain and the individual seamounts surrounded by lava cones high.
Lamont seamount chain | Geography and geomorphology
Global Census of Marine Life on Seamounts (commonly CenSeam) is a global scientific initiative, launched in 2005, that is designed to expand the knowledge base of marine life at seamounts. Seamounts are underwater mountains, not necessarily volcanic in origin, which often form subsurface archipelagoes and are found throughout the world's ocean basins, with almost half in the Pacific. There are estimated to be as many as 100,000 seamounts at least one kilometer in height, and more if lower rises are included. However, they have not been explored very much—in fact, only about half of one percent have been sampled—and almost every expedition to a seamount discovers new species and new information.
Global Census of Marine Life on Seamounts | Introduction
The St. Helena Seamount chain, also known as the St. Helena Seamounts, is an underwater chain of seamounts in the southern Atlantic Ocean. The chain has been formed by the movement of the African Plate over the Saint Helena hotspot.
St. Helena Seamount chain | Introduction
Seamounts are often found in groupings or submerged archipelagos, a classic example being the Emperor Seamounts, an extension of the Hawaiian Islands. Formed millions of years ago by volcanism, they have since subsided far below sea level. This long chain of islands and seamounts extends thousands of kilometers northwest from the island of Hawaii. There are more seamounts in the Pacific Ocean than in the Atlantic, and their distribution can be described as comprising several elongate chains of seamounts superimposed on a more or less random background distribution. Seamount chains occur in all three major ocean basins, with the Pacific having the most number and most extensive seamount chains.
Seamount | Grouping
The New England Seamounts were once at or above sea level. As time passed, however, and the chain moved farther away from the New England hotspot, the crust cooled and contracted, and the chain sank into the ocean. All the peaks are now a kilometer or more below the surface.
New England Seamounts | Formation
After a period of explosive activity near the ocean surface, the eruptions slowly die away. With eruptions becoming infrequent and the seamount losing its ability to maintain itself, the volcano starts to erode. After finally becoming extinct (possibly after a brief rejuvenated period), they are ground back down by the waves. Seamounts are built in a far more dynamic oceanic setting than their land counterparts, resulting in horizontal subsidence as the seamount moves with the tectonic plate towards a subduction zone. Here it is subducted under the plate margin and ultimately destroyed, but it may leave evidence of its passage by carving an indentation into the opposing wall of the subduction trench.
Seamount | Geochemistry and evolution
While the official name for these features refers to knolls, researchers in different disciplines see these features in different terms. These features are often referred to as seamounts where a seamount is described as any geographic isolated topographic feature on the seafloor taller than , including ones whose summit regions may temporarily emerge above sea level, but not including features that are located on continental shelves or that are part of other major landmasses. The seamounts are the site of volcanism from the late Cenozoic era. The knolls are high, stand deep at their base and at their summit. Many of the seamounts bear marks of tidal scour from water erosion, the result of millions of years of wear by a current moving at per second.
Graveyard Seamounts | Geography and geology
Guyots show evidence of having once been above the surface, with gradual subsidence through stages from fringed reefed mountain, coral atoll, and finally a flat-topped submerged mountain. Seamounts are made by extrusion of lavas piped upward in stages from sources within the Earth's mantle, usually hotspots, to vents on the seafloor. The volcanism invariably ceases after a time, and other processes dominate. When an undersea volcano grows high enough to be near or breach the ocean surface, wave action and/or coral reef growth tend to create a flat-topped edifice. However, all ocean crust and guyots form from hot magma and/or rock, which cools over time.
Guyot | Formation
They average ± in volume, but range from to . In addition to the eight main seamounts, there is a scattered disk of minor volcanic cones and flows about southeast of the chain.
President Jackson Seamounts | Introduction
All the seamounts in the group are complex northeast-southwest trending structures, consisting of parallel ridges separated by sediment-filled troughs. The ridges constructed run parallel to an ancient spreading center which has since been replaced in its role by the San Andreas Fault system. They are unique in this origin, as they are formed from the remnants of an old ocean-ridge spreading center. A series of "knobs" are aligned with the ridges; however the distinctive summit crater, evident in many oceanic volcanoes, is absent. This lack of a collapse crater suggests that magma was never stored in a chamber within the structure, as with most other volcanoes.
Davidson Seamount | Geology
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.
Cobb–Eickelberg Seamount chain | Introduction
Researcher Ridge is an underwater ridge in the Northern Atlantic Ocean. It appears to be a chain of seamounts named "Gollum Seamount", "Vayda Seamount", "Bilbo Seamount", "Gandalf Seamount", "The Shire Seamount", "Pippin Seamount", "Merry Seamount", "Molodezhnaya Seamount", "Frodo Seamount", "Sam Seamount" and "Mount Doom Seamount" that were likely formed by a hotspot.
Researcher Ridge | Introduction
Seamounts are underwater mountains that rise from the depths of the ocean, and whose summits can sometimes be found just a few hundred metres below the sea surface. To be classified as a seamount the summit must be 1000 m higher than the surrounding seafloor, and under this definition there are an estimated 1000–2800 seamounts in the Atlantic Ocean and around 60 in the Mediterranean Sea. Seamounts enhance water flow through localised tides, eddies, and upwelling, and these physical processes may enhance primary production. Seamounts may therefore be considered as hotspots of marine life; fauna benefit from the enhanced hydrodynamics and phytoplankton supply, and thrive on the slopes and summits.
Hotspot Ecosystem Research and Man's Impact On European Seas | Seamounts
The Tuscaloosa Seamount is an undersea mountain in the Hawaiian archipelago. It is located about northeast of the island Oʻahu. In contrast to the overwhelming majority of seamounts, the Tuscaloosa Seamount is not a submarine volcano. It is a huge block of rocks that broke off about two million years ago at the Nuʻuanu submarine landslide when the volcano Koʻolau collapsed. The Tuscaloosa Seamount is long and wide. Its shallow summit rises across the sea bottom but is below sea level.
Tuscaloosa Seamount | Introduction
They appear to have been formed under the influence both of fracture zones and of a melt anomaly that also formed a topographic anomaly west of the Lamont seamount chain along with elongated volcanic structures; a bathymetric swell is also noted around the seamounts as well as a deep depression that may be an isostatic moat. The volcanism may be ultimately the consequence of hotspot activity.
Lamont seamount chain | Geology
The President Jackson Seamounts are a series of seamounts (underwater volcanoes) located on the Pacific Plate, off of California. It consists of 8 seamounts, 4 independent and 4 morpohologically fused, just west of the northern Gorda Ridge. They are generally very small, and arranged linearly. The assembly consists of 8 seamounts arranged in a chain. The easternmost of the seamounts is located about east of the axial ridge that spawned the volcanoes, Gorda Ridge. The chain was mapped initially with SeaBeam equipment in 1985, however its incomplete coverage limited its usefulness. A GLORIA sidescan survey conducted in 1986 further established the rough size and locations of the seamounts.
President Jackson Seamounts | Introduction
In marine geology, a guyot (pronounced ), also known as a tablemount, is an isolated underwater volcanic mountain (seamount) with a flat top more than below the surface of the sea. The diameters of these flat summits can exceed . Guyots are most commonly found in the Pacific Ocean, but they have been identified in all the oceans except the Arctic Ocean.
Guyot | Introduction
Daikakuji Seamount is a seamount (underwater volcano) and the southwesternmost volcanic feature in the Hawaiian Emperor chain bend area.
Daikakuji Guyot | Introduction
Tropic Seamount is a Cretaceous seamount southwest of the Canary Islands, north of Cape Verde and west of the Western Sahara, one of a number of seamounts (a type of underwater volcanic mountain) in this part of the Atlantic Ocean. It was probably formed by volcanic processes triggered by the proximity to the African continent. Tropic Seamount is located at a depth of and has a summit platform with an area of . Tropic Seamount is formed by volcanic rocks including basalt and trachyte and was probably an island at first; for reasons unknown it sank to its present-day depth.
Tropic Seamount | Introduction
Gascoyne Seamount, also called Gascoyne Guyot or Gascoyne Tablemount, is a guyot in the Tasman Sea of the South Pacific Ocean. Located east of the Australian coastal town of Bermagui, Gascoyne Seamount is the southernmost and youngest seamount of the Tasmantid Seamount Chain. This is an underwater mountain range extending some to the north. The Tasmantid Seamount Chain has resulted from the Indo-Australian Plate moving northward over a stationary hotspot. The seamount is about 7 million years old. It incorporates a tropical to subtropical, very shallow water calcareous algal/encrusting foraminiferid biota, suggesting deposition in water deep. Age diagnostic forms have not been recovered.
Gascoyne Seamount | Introduction
A mountain chain is a row of high mountain summits, a linear sequence of interconnected or related mountains, or a contiguous ridge of mountains within a larger mountain range. The term is also used for elongated fold mountains with several parallel chains ("chain mountains"). While in mountain ranges, the term mountain chain is common, in hill ranges a sequence of hills tends to be referred to a ridge or hill chain. Elongated mountain chains occur most frequently in the orogeny of fold mountains, (that are folded by lateral pressure), and nappe belts (where a sheetlike body of rock has been pushed over another rock mass).
Mountain chain | Introduction
Guide Seamount is a seamount in the eastern Pacific Ocean, about 16.6±0.5 million years old. It is similar in shape and orientation to the nearby Davidson, Pioneer, Rodriguez, and Gumdrop seamounts. It is named for the United States Coast and Geodetic Survey survey ship "USC&GS Guide". Guide Seamount is constructed of four nearly parallel volcanic ridges, separated by sediment-filled throughs. These are aligned parallel to magnetic anomalies in the underlying oceanic crust. It is very similar in shape and structure to the nearby Davidson Seamount, except that it is smaller, at approximately by . It rises about above the seafloor and sits at depth of .
Guide Seamount | Introduction
The crust underneath these seamounts tends to subside as it cools, and thus the islands and seamounts sink. Continued subsidence balanced by upward growth of the reefs led to the formation of thick carbonate platforms. Sometimes volcanic activity continued even after the formation of the atoll or atoll-like structure, and during episodes where the platforms rose above sea level erosional features such as channels and blue holes developed. The formation of many seamounts has been explained by the hotspot theory, which suggests that the chains of volcanoes become progressively older along the length of the chain, with an erupting volcano only at one end of the system.
Resolution Guyot | Regional setting
In addition there are long gullies formed either by erosional or volcanic processes, as well as parasitic vents and volcanic ridges.
Tropic Seamount | Local
Crough Seamount (named after the geologist Thomas Crough) is a seamount in the Pacific Ocean, within the exclusive economic zone of Pitcairn. It rises to a depth of and is paired with a taller but overall smaller seamount to the east. This seamount has a flat top and probably formed an island in the past. It is about 7-8 million years old, although a large earthquake recorded at its position in 1955 may indicate a recent eruption. The seamount appears to be part of a long geological lineament with the neighbouring Henderson and Ducie islands, as well as the southern Tuamotus and Line Islands.
Crough Seamount | Introduction
The Cobb hotspot has created an underwater mountain range that extends to the northwest and ends at the Aleutian Trench. The oldest mount in the chain is the Marchland Seamount, at 30 to 43 Ma (million years old). The old, northwestern end of the chain collides with a subduction zone; therefore, the true age of the hotspot is difficult to determine as the oceanic crust is being consumed. Axial Seamount is the hotspot's most recent eruptive center, which last erupted in 2015, 2011 and 1998. The central ridge of the hotspot is thicker than the surrounding crust by a few kilometers and may be accumulated buildup from the magma released at the hotspot, which is essentially a submarine volcano with a root in diameter, reaching a depth of beneath the volcano.
Cobb hotspot | Cobb Seamount chain
The Pacific Ocean seafloor, especially the Mesozoic seafloor, contains most of the world's guyots (also known as tablemounts). These are submarine mountains which are characterized by steep slopes, a flat top and usually the presence of corals and carbonate platforms. While there are some differences to present-day reef systems, many of these seamounts were formerly atolls. Some atolls still exist, for example at Pikinni. All these structures originally formed as volcanoes in the Mesozoic ocean. Fringing reefs may have developed on the volcanoes, which then became barrier reefs as the volcano subsided and turned into an atoll. The crust underneath these seamounts tends to subside as it cools, and thus the islands and seamounts sink.
Wōdejebato | Regional setting
After they have subsided and sunk below the sea surface such flat-top seamounts are called "guyots" or "tablemounts". The Earth's oceans contain more than 14,500 identified seamounts of which 9,951 seamounts and 283 guyots, covering a total area of , have been mapped but only a few have been studied in detail by scientists. Seamounts and guyots are most abundant in the North Pacific Ocean, and follow a distinctive evolutionary pattern of eruption, build-up, subsidence and erosion. In recent years, several active seamounts have been observed, for example Loihi in the Hawaiian Islands. Because of their abundance, seamounts are one of the most common marine ecosystems in the world.
Seamount | Introduction
This seamount is about 90 x 40 km, it rises from ocean depths of about 4500 m well into the euphotic zone. The summit topography is rather disturbed with a summit plateau ~ 6 x 3 km in about 120 m and a peak reaching up to 55 m below the water surface.
Ampère Seamount | Introduction
The seamount is very close to the "V"-shaped bend in the Hawaiian-Emperor seamount chain, and thus would be useful in understanding the exact age of the bend. Although few dredge samples are available, they have all been reliably dated at 47 million years (Sharp and Clague, Science, 313, 1281-84, 2006), during the Eocene epoch of the Paleogene period. During the cruise SO112 of the "R/V SONNE", high resolution bathymetric mapping was conducted, showing that Daikakuji is nearly in diameter and nearly in height, with a summit lying underwater. Because of its flat capped top, Daikakuji is considered a guyot. A smaller, younger, secondary guyot just east of the main mass overlaps its slope.
Daikakuji Guyot | Geology
The Pacific Ocean is characterized by long island chains, which typically extend from the southeast to the northwest in direction of the motion of the Pacific Plate. Often, such chains begin in the southeast with volcanoes such as Hawaii that become progressively more eroded northwestward and eventually end as series of atolls. This has led to the suggestion that they are formed by deep sources over which the Pacific Plate drifts and eventually carries the volcano away from its magma source. These sources are known as "hotspots", and their total number has been estimated to be between 42 and 117.
Macdonald seamount | Regional setting
Possibly, as such a seamount or a seamount chain subducted it indented the trenches, forming a re-entrant.
Erimo Seamount | Regional
The seamount is elongated in about northeast-south-southwest direction, with ridges radiating from its northern sector and the lower southern sector spreading southwestward like a tongue. This elongation matches the trend of magnetic lineations on the surrounding seafloor, implying that it may be controlled by the surrounding tectonic environment. The submarine slopes of the seamount are quite steep and show two benches at and depth. The seamount has dimensions of on the seafloor. About 15–20 parasitic vents dot the deeper flanks of the seamount and reach height, and small ridges en echelon to Vesteris are found on the southeastern flank. The total volume of the seamount is about .
Vesteris Seamount | Geography and geology
The Bear Seamount is a guyot or flat-topped underwater volcano in the Atlantic Ocean. It is the oldest of the New England Seamounts, which was active more than 100 million years ago. It was formed when the North American Plate moved over the New England hotspot. It is located inside the Northeast Canyons and Seamounts Marine National Monument, which was proclaimed by President of the United States Barack Obama to protect the seamount's biodiversity.
Bear Seamount | Introduction
Alternative names for the Tasmantid Seamount Chain include the Tasmantid Seamounts, Tasman Seamounts, Tasman Seamount Chain, Tasmantide Volcanoes or simply the Tasmantids.
Tasmantid Seamount Chain | Introduction
Bowie Seamount is a large submarine volcano in the northeastern Pacific Ocean, located west of Haida Gwaii, British Columbia, Canada. The seamount is also known as Bowie Bank. In the Russian language, Bowie is called Гора Бауи (Gora Baui), which literally means Mount Bowie. In Haida language it is called SG̱aan Ḵinghlas, meaning Supernatural One Looking Outward. It is named after William Bowie of the U.S. Coast and Geodetic Survey. The volcano has a flat-topped summit rising about above the seabed, to below sea level. The seamount lies at the southern end of a long underwater volcanic mountain range called the Pratt-Welker or Kodiak-Bowie Seamount chain, stretching from the Aleutian Trench in the north almost to Haida Gwaii in the south.
Bowie Seamount | Introduction
The Bear Seamount is the first guyot in a chain of about 30 extinct volcanoes extending in a straight line south-eastwards from the edge of the continental shelf near Woods Hole, Massachusetts to north-east of Bermuda. These seamounts resulted from the movement of a mantle plume hotspot. This hotspot is now under the Great Meteor Seamount. The chain rises about above the surrounding Sohm Abyssal Plain. Over time they have been eroded and have developed flat table-like summits surrounded by slopes with an inclination of about 20°. The currents in the vicinity of the Bear Seamount include the warm water Gulf Stream flowing towards the north east, the deep boundary current flowing along the continental shelf towards the south west, and the deep, icy cold Arctic bottom water that flows past the lower flanks of the chain.
Bear Seamount | Formation
The Fogo Seamounts, also called the Fogo Seamount chain, are a group of seamounts located about offshore of Newfoundland and southwest of the Grand Banks of Newfoundland. They consist of basaltic submarine volcanoes that formed during the Early Cretaceous period. The volcanic activity that formed the Fogo Seamounts could have originated in two ways. They may have formed as a result of magma rising along a linear fault zone or from the North American Plate passing over the Canary or Azores hotspots.
Fogo Seamounts | Introduction
Resolution Guyot is part of the western Mid-Pacific Mountains, located west of Hawaii, north-northeast of the Marshall Islands. Unlike conventional Pacific Ocean island chains, the Mid-Pacific Mountains are a group of oceanic plateaus with guyots (also known as tablemounts)) that become progressively younger towards the east. Other guyots in the Mid-Pacific Mountains are Sio South, Darwin, Thomas, Heezen, Allen, Caprina, Jacqueline and Allison. The seamount is about high and rises from a raised seafloor to a depth of about . At a depth of it is capped off by a wide rather flat and roughly circular summit platform with a high rim and a moat inside of this rim.
Resolution Guyot | Local setting
This flat summit is covered by high volcanic cones and features terraces at the margin of the summit as well as ridges that point due north, east, south and west. Volcanic cones are concentrated in the southern and eastern parts of the summit platform. The seamount has a volume of about , similar to other Atlantic Ocean volcanoes. Raised beaches have been reported from Tropic Seamount. The outer slopes of the seamount become steeper to the summit perhaps due to geochemical differences between the rocks that form the lower slopes and these of the upper slopes. They are cut by curved flank collapses that open to the northeast, southeast, southwest and northwest; these collapses have cut into the volcanic edifice and have left ridges between the individual collapses which give the seamount its four-point star form and deposited debris around the seamount, although the deposits are not recognizable probably because they are old and buried beneath sediments.
Tropic Seamount | Local
The Condor seamount is a submarine mountain located at 17 km west-southwest of Faial Island in the Azores , about 1800 m high, 39 km long and 23 km wide, stretching from the 185 m depth up to 2003 m. It is an elongated shaped volcano, oriented East-West, with the top relatively flat with smooth sedimentary flanks. Most seamounts lie in deep sea and/or open ocean, and thus are inaccessible and difficult to study. The Condor bank, constitutes an interesting case study due to its accessibility, located close to Faial island, and for that reason is also known by “Condor-Terra”.
Condor seamount | Introduction
A seamount such as Davidson is an underwater volcano; this one rises above the surrounding ocean floor. Although there are over 30,000 seamounts in the Pacific Ocean alone, only about 0.1% of them have been explored. The aqueous environment of the seamount means that it behaves differently from volcanoes on land. Its surface is composed mostly of blocky lava flows, although some pillow lava, which is the typical lava type of a seamount, prevails at the deeper flank. The summit is composed of layered deposits of volcanic ash and pyroclastic material. These rocks indicate mildly explosive eruptions of gas-rich lava near the summit of the volcano.
Davidson Seamount | Geology
On the other end of the ridge, "Buffon" seamount rises to a depth of and likewise shows evidence of having emerged above sea level, as well as of extensive erosion. The seamounts were originally named after letters of the alphabet A-Z followed by Aa-Hh; later they were numbered through from west to east and names based on scientists such as Ampere proposed.
Foundation Seamounts | Geography
Takuyo-Daisan is a guyot that rises to a minimum depth of and is capped by an approximately square-shaped surface platform at about depth which has a surface area of about . Depressions up to deep cover the flat top. The top is surrounded by a wide and up to high ridge, especially on the northeastern and southern sides. It may be either a bioherm or a karst landform. A - high structure may be part of the old volcanic edifice; the interface between the carbonate platform and the volcanic basement has a sloping aspect. Away from the platform, the seamount has steep slopes probably formed by short lava flows that rise above the seafloor.
Takuyo-Daisan | Local
Numerous craters and small volcanic cones dot its flanks which bear evidence of sector collapses.
Cadamosto Seamount | Geography and geomorphology
The ridges contain individual volcanoes and reach lengths of over ; in the Italian and Bach Ridges the volcanoes are high. The Musicians horst and the Southern Ridges are additional features of the Musicians Seamounts. Terrain observed by remotely operated vehicles shows large blocks, pillow lavas, flat terrain, lava flows and talus. The total number of seamounts is about 65, some of which Henry William Menard named after 18th century musicians. Among the seamounts known by name are:
Musicians Seamounts | Geography and geomorphology
A mid-ocean ridge is a general term for an underwater mountain system that consists of various mountain ranges (chains), typically having a valley known as a rift running along its spine, formed by plate tectonics. This type of oceanic ridge is characteristic of what is known as an oceanic spreading center, which is responsible for seafloor spreading.
List of submarine topographical features | Mid-ocean ridges
Most seamounts are built by one of two volcanic processes, although some, such as the Christmas Island Seamount Province near Australia, are more enigmatic. Volcanoes near plate boundaries and mid-ocean ridges are built by decompression melting of rock in the upper mantle. The lower density magma rises through the crust to the surface. Volcanoes formed near or above subducting zones are created because the subducting tectonic plate adds volatiles to the overriding plate that lowers its melting point. Which of these two process involved in the formation of a seamount has a profound effect on its eruptive materials. Lava flows from mid-ocean ridge and plate boundary seamounts are mostly basaltic (both tholeiitic and alkalic), whereas flows from subducting ridge volcanoes are mostly calc-alkaline lavas.
Seamount | Geochemistry and evolution
Yuryaku Seamount (also called "Yuryaku Guyot") is a seamount (underwater volcano) and guyot (flat-topped) located northwest of Hawaii. It is located a little southwest of the V-shaped bend separating the Emperor Seamounts from the older Hawaiian islands, all of the Hawaiian-Emperor seamount chain in the North Pacific Ocean.
Yuryaku Seamount | Introduction
Musicians Seamounts are a chain of seamounts in the Pacific Ocean, north of the Hawaiian Ridge. There are about 65 seamounts, some of which are named after musicians. These seamounts exist in two chains, one of which has been attributed to a probably now-extinct hotspot called the Euterpe hotspot. Others may have formed in response to plate tectonics associated with the boundary between the Pacific Plate and the former Farallon Plate. The seamounts were constructed on young oceanic crust during the Cretaceous, but a second phase of volcanic activity took place during the Eocene. Deep sea coral reefs occur on the seamounts.
Musicians Seamounts | Introduction
The Seewarte Seamounts, also known as the Seewarte Seamount Chain, Atlantis-Great Meteor Seamount Chain and the Atlantis-Plato-Cruiser-Great Meteor Seamount Group, is a north-south trending group of extinct submarine volcanoes in the northern Atlantic Ocean south-southeast of the Corner Rise Seamounts. The Seewarte Seamounts have been interpreted to have formed as a result of the African Plate traveling over the New England hotspot.
Seewarte Seamounts | Introduction
The Western Pacific Ocean features many seamounts with flat tops at depths of below sea level which are known as guyots. They were considered to be remnants of eroded islands before Cretaceous carbonate platforms were discovered on them which resemble present-day atolls although they do not have exactly the same properties. Later similar submarine mountains were identified elsewhere in the Pacific Ocean as well. Menard 1958 suggested that the Western Pacific guyots once were part of an elevated region known as the Darwin Rise, later compared to present day French Polynesia. Many of these seamounts originally formed in the South Pacific, such as in French Polynesia, where a number of recent volcanoes and volcanic chains can be found.
Takuyo-Daisan | Regional
The chain-like arrangement of summits and the formation of long, jagged mountain crests – known in Spanish as sierras ("saws") – is a consequence of their collective formation by mountain building forces. The often linear structure is linked to the direction of these thrust forces and the resulting mountain folding which in turn relates to the fault lines in the upper part of the earth's crust, that run between the individual mountain chains. In these fault zones, the rock, which has sometimes been pulverised, is easily eroded, so that large river valleys are carved out. These, so called longitudinal valleys reinforce the trend, during the early mountain building phase, towards the formation of parallel chains of mountains.
Mountain chain | Formation of parallel mountain chains
Many of the volcanoes are named after former emperors of Japan. The seamount chain extends to the West Pacific, and terminates at the Kuril–Kamchatka Trench, a subduction zone at the border of Russia.
Hawaiian–Emperor seamount chain | Regions
The Eratosthenes Seamount or Eratosthenes Tablemount is a seamount in the Eastern Mediterranean about 100 km south of western Cyprus. Unlike most seamounts, it is a carbonate platform not a volcano. It is a large, submerged massif, about 120 km long and 80 km wide. Its peak lies at the depth of 690 m and it rises 2000 m above the surrounding seafloor, which is located at the depth of up to 2,700 m and is a part of the Herodotus Abyssal Plain. It is one of the largest features on the Eastern Mediterranean seafloor. In 2010 and 2012 the Ocean Exploration Trust's vessel EV Nautilus explored the seamount looking for shipwrecks.
Eratosthenes Seamount | Introduction
Seamounts within the Corner Rise Seamount chain include:
Corner Rise Seamounts | Seamounts
A seamount is a mountain rising from the ocean seafloor that does not reach the ocean surface. They are defined by oceanographers as independent features that rise at least 1,000 meters above the seafloor. Seamounts became interesting during the 1960s, when it was discovered that they can maintain large stocks of commercially important fishes and invertebrates. From 1968 to about 1990, foreign fleets harvested pelagic armorhead across seamounts in the Hawaiian Ridge. Since 1984, fishing has been prohibited there so the stock can recover. Generally, seamounts are found in the high seas, outside the continental shelves, and outside the jurisdiction of any nation's EEZ.
Fishing industry in the United States | Seamounts
Channels, debris flow fronts and levees decorate its slopes. Noticeable ridges emanate from the east-southeastern, southwestern, west-northwestern and north-northeastern corners of the seamount; they appear to be rift zones, and flank cones are found on the eastern slopes. The southern slopes feature slump deposits, and the entire seamount is surrounded by a sediment fan. The volume of the entire seamount is about . Two large seamounts lie west and southwest of Takuyo-Daisan with a smaller seamount between the two; Takuyo-Daini is the western one and Jensen seamount the south-western one. The seafloor underneath Takuyo-Daisan has an age of 143 million years.
Takuyo-Daisan | Local
Coral Patch Seamount is a seamount (underwater mountain) between Madeira and Portugal in the North Atlantic Ocean. It is an elongated long and wide mountain that rises to a depth of about , with nine volcanic cones on its summit. It has steeper southern slopes and a gentle northern slope. To its west lies Ampére Seamount, and together with several neighbouring seamounts it is one of the Horseshoe Seamounts. The seamount was probably formed by the Madeira hotspot in the Miocene, together with buckling processes in the oceanic crust. It was initially probably an island. There is evidence of submarine landslides and active faults which constitute a tsunami hazard; the 1755 Lisbon earthquake may have occurred north of the seamount.
Coral Patch Seamount | Introduction
Seamounts can form in a wide variety of tectonic settings, resulting in a very diverse structural bank. Seamounts come in a wide variety of structural shapes, from conical to flat-topped to complexly shaped. Some are built very large and very low, such as Koko Guyot and Detroit Seamount; others are built more steeply, such as Loihi Seamount and Bowie Seamount. Some seamounts also have a carbonate or sediment cap. Many seamounts show signs of intrusive activity, which is likely to lead to inflation, steepening of volcanic slopes, and ultimately, flank collapse. There are also several sub-classes of seamounts. The first are guyots, seamounts with a flat top.
Seamount | Structure
The Musicians Seamounts lie in the north-central Pacific, north of the Hawaiian Ridge north and northwest of Necker Island, extending over a length of . The seamounts were formerly known as the North Hawaiian Seamount Range and were among the first submarine mountains to be thoroughly researched. The seamounts consist of two separate chains (one trending in north-south direction parallel to the Emperor Seamounts and the other in northwest-southeast direction parallel to the northern Line Islands) of ridges that extend east-west and seamounts. Seamounts have usually an elliptical cross section and heights of and no flat tops like other seamounts south of the Hawaiian Ridge; the highest is Liszt Seamount whose summit has a depth of .
Musicians Seamounts | Geography and geomorphology
The chain has been produced by the movement of the ocean crust over the Hawaii hotspot, an upwelling of hot rock from the Earth's mantle. As the oceanic crust moves the volcanoes farther away from their source of magma, their eruptions become less frequent and less powerful until they eventually cease to erupt altogether. At that point erosion of the volcano and subsidence of the seafloor cause the volcano to gradually diminish. As the volcano sinks and erodes, it first becomes an atoll island and then an atoll. Further subsidence causes the volcano to sink below the sea surface, becoming a seamount and/or a guyot.
Hawaiian–Emperor seamount chain | Aging
The seamount is named after the research vessel and is also known as Horizon Ridge, Horizon Tablemount, Gora Khorayzn and . During the Deep Sea Drilling Project, the drill cores called Site 44 and Site 171 were taken on Horizon Guyot in 1969 and 1971, respectively; a further drill core was obtained north of the seamount at Site 313 in 1973. This seamount is the best studied seamount of the Mid-Pacific Mountains and more is known about its morphology than any other seamount of the Mid-Pacific Mountains.
Horizon Guyot | Name and research history
Compared to mid-ocean ridge seamounts, subduction zone seamounts generally have more sodium, alkali, and volatile abundances, and less magnesium, resulting in more explosive, viscous eruptions. All volcanic seamounts follow a particular pattern of growth, activity, subsidence and eventual extinction. The first stage of a seamount's evolution is its early activity, building its flanks and core up from the sea floor. This is followed by a period of intense volcanism, during which the new volcano erupts almost all (e.g. 98%) of its total magmatic volume. The seamount may even grow above sea level to become an oceanic island (for example, the 2009 eruption of Hunga Tonga).
Seamount | Geochemistry and evolution
Daiichi-Kashima Seamount is a guyot in the Pacific Ocean off Japan. It is about high and reaches a depth of . Daiichi-Kashima formed during the Barremian as a result of volcanic activity; during the Albian reefs formed on the seamount and generated a limestone cap. The seamount later. The seamount has been approaching the Japan Trench and a noticeable vertical offset of about between the eastern and western halves of Daiichi-Kashima appears to be the result of normal faulting as the seamount enters the trench, with the western half dropping down; it may also reflect a past sector collapse when the volcano was still active.
Daiichi-Kashima Seamount | Introduction
The seamount was named for the 58th emperor of Japan, Emperor Koko (A.D. 885-887) by geologist Thomas Davies and his colleagues in 1972, based on the results from a bathymetric expedition and contents of two dredge huals, led by Thomas Washington and undertaken with the ship "Aries-7". The seamount is elongate in shape, aligned northwest-southeast (the same direction as the chain), and has a gentle slope and a large, flat top. Koko Seamount also has a lot of small reefal bodies on its slopes. It rises from the abyssal floor about in height. A prominent south-trending ridge extends about from the summit area in the direction of Kimmei Seamount, to the southeast.
Koko Guyot | Geology and characteristics
Discovery Seamounts are a chain of seamounts in the Southern Atlantic Ocean, which include the Discovery Seamount. The seamounts lie east of Gough Island and once rose above sea level. Various volcanic rocks as well as glacial dropstones and sediments have been dredged from the seamounts. The Discovery Seamounts appear to be a volcanic seamount chain controlled by the Discovery hotspot, which had its starting point either in the ocean, Cretaceous kimberlite fields in southern Namibia or the Karoo-Ferrar large igneous province. The seamounts formed between 41 and 35 million years ago; presently the hotspot is thought to lie southwest of the seamounts, where there are geological anomalies in the Mid-Atlantic Ridge that may reflect the presence of a neighbouring hotspot.
Discovery Seamounts | Introduction
This fault, which appears to be split in two or three subsidiary faults separated by grabens, extends past the Daiichi-Kashima seamount and covers a length of ; evidently Daiichi-Kashima has been split in half by the fault, which is much younger than the ocean floor and moved at a rate of but does not appear to be presently active in light of the sediment cover on the scarp. Aside from a normal motion, the western half of the seamount has also been moved away from the eastern half and is tilted west. The seamount appears to be part of a seamount chain called Joban Seamount Chain or Kashima-Ryofu No.1 that formed during the Cretaceous in the Equatorial Pacific and about 30° south of their present-day position.
Daiichi-Kashima Seamount | Local
The Pacific Ocean contains several long seamount chains, formed by hotspot volcanism. These include the Hawaiian–Emperor seamount chain, the Tasmantid Seamount Chain, the Lord Howe Seamount Chain and the Louisville Ridge.
Geology of the Pacific Ocean | Seamount chains and hotspots
Not all of these hotspots are necessarily fed by a deep continuous mantle plume; some may be nourished by discrete batches of melting material that rise through the mantle. Other chains may be controlled by mantle flow towards a spreading ridge, which has been proposed for the Musicians chain.
Musicians Seamounts | Geologic context
The seamounts in the field are typically less than wide but several kilometres wide; seamounts that are part of a ridge are between high. The total volume of rocks in the seamount province is about .
Rano Rahi seamounts | Geography and geomorphology
Ngatemato seamounts (Name derived from a ruling family in Rapa) are a series of seamounts in the southern Pacific Ocean. These seamounts have the shape of ridges and display calderas. The Aureka () and Make () seamounts are part of the Ngatemato track. Dredged rocks are weakly tholeiitic basalts of Oligocene age. They are about high and wide at their base. Despite being smaller in size than the Macdonald seamounts however the Ngatemato seamounts have larger volumes which is masked by stronger plate deformation; the magma output that created the Ngatemato and Taukina chains when summed up is about .
Ngatemato seamounts | Introduction
Lava flows or landslide deposits appear to surround a number of the seamounts. A number of processes has been proposed to explain the formation of seamounts close to spreading ridges. In the case of Rano Rahi, both line-like sources and point-like sources of magma may be involved, with a common source of magma that results in a tradeoff between the sizes of neighbouring seamount chains. Seismic tomography has identified low-velocity material beneath the seamounts which may be flows in the mantle. The neighbouring Pukapuka ridge appears to be related to the Rano Rahi seamounts, which are located east of its eastern end and form a wedge-shaped extension thereof.
Rano Rahi seamounts | Geology
The Tasmantid and Lord Howe seamount chains are both broadly within the Tasman basin (the abyssal plain between Lord Howe Rise and the Australian continental shelf), and lie on opposite sides of Dampier Ridge (a submerged continental fragment).
Lord Howe Seamount Chain | Introduction
The seamount is located in the Greenland Sea-Norwegian Sea, west of due north from Jan Mayen Island and in between Norway and Greenland. Vesteris Seamount is an isolated volcanic seamount that reaches a depth of below sea level and with two summits that rise from a plateau at depth; it is likely that the summit once emerged from the sea. The summit area of the seamount is flat, probably due to wave erosion during the Weichselian glaciation, and sediment cover is scarce. Lava flows extend from the summit area to depths of almost , and sheet flows, scarps, pillow lavas, lava tubes and lava debris have been observed on the seamount.
Vesteris Seamount | Geography and geology
Jingū Seamount, also called Jingū Guyot, is a guyot of the Hawaiian-Emperor seamount chain in the Pacific Ocean. It erupted 55 million years ago. The seamount is elongated in structure, running north–south, and has an oval shaped crater in the center, which is evidence of collapse when above sea level. The seamount was named in 1954 by Robert S. Dietz, after Japanese Empress Jingū.
Jingū Seamount | Introduction
Meiji Seamount, named after Emperor Meiji, the 122nd Emperor of Japan, is the oldest seamount in the Hawaiian-Emperor seamount chain, with an estimated age of 82 million years. It lies at the northernmost end of the chain, and is perched at the outer slope of the Kuril-Kamchatka Trench. Like the rest of the Emperor seamounts, it was formed by the Hawaii hotspot volcanism, grew to become an island, and has since subsided to below sea level, all while being carried first north and now northwest by the motion of the Pacific Plate. Meiji Seamount is thus an example of a particular type of seamount known as a guyot, and some publications refer to it as Meiji Guyot.
Meiji Seamount | Introduction
Rybin-yaha (1923)- a river, flowing into the Gulf of Ob, Kara Sea( Mouth 69º01' N 72º31’ Е). Rybin was the first person to put the river on the charts (Russian charts 15337, 13335). Rybin seamount (1999)- a seamount in the Atlantic Ocean (31°47'2N, 12°49'4W), north-west of the Canary Islands, with a minimum depth of 412 meters compared to the surrounding depths of 2800–3600 meters.The relative height of the seamount is 2788 meters. In 1999, the Commission for Geographical names of the International Hydrographic Organisation and the Intergovernmental Oceanographic committee named an underwater mount with the smallest depth of 412 meters and the relative height of 2700 meters after Georgy – Rybin seamount.
Georgy Rybin | Memory
The overthrust folds of a nappe belt (e.g. the Central Alps) are formed in a similar way. Although the fold mountains, chain mountains and nappe belts around the world were formed at different times in the earth's history, all during their initial mountain building phases, they are nevertheless morphologically similar. Harder rock forms continuous arêtes or ridges that follow the strike of the beds and folds. The mountain chains or ridges therefore run approximately parallel to one another. They are only interrupted by short, usually narrow, transverse valleys, which often form water gaps. During the course of earth history, erosion by water, ice and wind carried away the highest points of the mountain crests and carved out individual summits or summit chains.
Mountain chain | Formation of parallel mountain chains
The Vance Seamounts are a group of seven submarine volcanoes located west of the Juan de Fuca Ridge. Most of the seamounts contain a caldera. They are the southernmost of several near-ridge chains located on the Pacific Plate, stemming from the Juan de Fuca Ridge. The easternmost five of the seven were surveyed using SeaBeam bathymetry. A chemical analysis of the lavas of the volcanoes indicated that the materials erupted from the volcanoes are relatively primitive. With the exception of one, the volcanoes form a nearly linear chain of circular volcanic cones. The second volcano from the northwest is not discretely shaped like the rest, rather it is a rough structure of lava cones and flows, which cover an area of at least .
Vance Seamounts | Introduction
Monowai is a volcanic seamount to the north of New Zealand. It is formed by a large caldera and a volcanic cone just south-southeast from the caldera. The volcanic cone rises to depths of up to but its depth varies with ongoing volcanic activity, including sector collapses and the growth of lava domes. The seamount and its volcanism were discovered after 1877, but only in 1980 was it named "Monowai" after a research ship of the same name. The subduction of the Pacific Plate beneath the Australia Plate has given rise to volcanic and hydrothermal activity on the Kermadec Ridge that Monowai is part of.
Monowai (seamount) | Introduction
The Tasmantid Seamount Chain is a long chain of seamounts in the South Pacific Ocean. The chain consists of over 16 extinct volcanic peaks, many rising more than from the seabed. It is one of the two parallel seamount chains alongside the East Coast of Australia; the Lord Howe and Tasmantid seamount chains both run north-south through parts of the Coral Sea and Tasman Sea. These chains have longitudes of approximately 159°E and 156°E respectively. Like its neighbour, the Tasmantid Seamount Chain has resulted from the Indo-Australian Plate moving northward over a stationary hotspot. It ranges in age from 40 to 6 million years old.
Tasmantid Seamount Chain | Introduction
The seamount chain provides a unique habitat for deep sea marine creatures. Coral formations grow on the rocky outcrops, resembling underwater forests that provide shelter for invertebrates and fish. Due to the expense and difficulties of studying the deep ocean, little was known of the creatures that inhabited the New England Seamounts. In fact, before recent expeditions, there was only one known coral species in the entire chain. Since 2000, marine biologists, during various exploratory studies, have caught and classified over 203 species of fish and 214 species of invertebrates on the Bear Seamount. This range of diversity suggests that other seamounts may harbour more unknown macro-organisms.
New England Seamounts | Biota
The Pacific Ocean contains several long seamount chains, formed by hotspot volcanism. These include the Hawaiian–Emperor seamount chain and the Louisville Ridge.
Pacific Ocean | Seamount chains