underwater volcanoes. Underwater Vesuvius: Volcanoes on the seabed can kill all life
Life in surface waters ocean, on which the volume of greenhouse gases absorbed by the ocean depends, is supported by the activity of underwater volcanoes.
This happens because underwater volcanoes supply phytoplankton with iron compounds necessary for photosynthesis. This is stated in an article by American scientists in the journal Nature Geoscience. Iron particles, a necessary element for most food chains, are very rare in surface ocean waters.
Previously, it was believed that they get there mainly with the waters of rivers and streams. Scientists from the University of Minnesota have shown that most of the iron needed for phytoplankton can come to the surface from the very bottom. “Deep volcanoes at the bottom of the ocean supply its waters with a large amount of iron, but whether this iron gets into the upper layers of the ocean and whether it is absorbed by living organisms depends on the chemical form of iron. At the bottom, we managed to find iron in a completely unexpected form,” said the head of the study, Professor Brandi Tonera.
Previously, scientists believed that most of the iron ejected by underwater volcanoes settles to the bottom in inorganic form.
With the help of remote control deep-sea vehicles researchers collected particle samples from different volcanically active regions Pacific Ocean. Volcanoes create so-called hydrothermal jets - the water in them reaches a temperature of several hundred degrees, but due to the enormous pressure it does not turn into steam. These hydrothermal jets contain a large number of dissolved substances, including iron ions.
These ions, as the researchers were able to show, further react with organic compounds dissolved in water, form small particles of submicron size, and are carried away by underwater currents.
Unlike iron, which enters the ocean from rivers and streams in a more oxidized form of Fe, hydrothermal plumes create large quantity more suitable for the assimilation by living organisms of ferrous iron Fe.
The authors of the article hope that their discovery will lead to a revision of existing opinions about the cycle of iron and carbon in the ocean. It is likely that such a revision will affect experimental work on the "fertilization" of the ocean with iron compounds in order to combat global warming.
underwater volcanoes
Underwater volcanoes are located at the bottom of the ocean and are much larger and more energetic than terrestrial ones. They are the main source of tsunamis on Earth.
On our planet, volcanoes located under water produce ¾ of all magma ejected from the bowels of the planet per year. Most active volcanoes are located at the junction of tectonic plates in the so-called oceanic ridges. These ridges pass in their mass deep under water, so most of the eruptions are not visible to humans. Yes, and it is often not possible to notice the eruption that has occurred with the help of acoustic equipment. This is related to the fact that great depths, when magma is ejected into cold water, it immediately cools down, turning into volcanic glass, so it does not boil, so it is impossible to hear it.
Underwater volcanoes grow in height. As they erupt, they are overgrown with volcanic mass, which does not scatter far, as on the surface of the earth. Over time, the volcano goes out, having used up the reserves of its magma. If during its life the volcano reaches the surface of the water, then it gives birth to a volcanic island. and disappears over time. Scientists estimate that most of the 30,000 known seamounts are extinct volcanoes.
Despite the destructive power of volcanoes, it is reliably known that the eruption releases organic compounds into the water, which are necessary for the development of phytoplankton. This, in turn, supports the diversity of the entire animal world.
Due to the fact that volcanoes give life to ocean flora, it has been suggested that the greater activity of volcanoes could give impetus to a large increase in the population of marine animals and plants. With the death and decomposition of such an amount of live mass, all the oxygen dissolved in water was absorbed, which led to the extinction of 70% of animal species from suffocation.
This theory has many controversial points: Firstly, a uniform increase in animal weight will not lead to an excess of decomposing animals, because. they will be devoured by scavengers, who live in abundance at the bottom. Secondly, the found evidence of volcanic activity only confirms that it was, but does not prove that there was so much of it. how much is needed for such a mass extinction.
Another young volcano formed in 1973 as a result of an eruption on the outskirts of the city of Heimaey. The eruption of Eldfetl was both for scientists and for local residents complete surprise. Emissions from the volcano continued until July 1974, after which Eldfell lost activity. New eruptions, according to experts, are unlikely. The height of Eldfell is about 200 meters.
It's about the Yasur volcano. This is very old volcano, which scientists believe formed about a million years ago, but was discovered only in 1774, when the first documented eruption occurred. Yasur is also considered one of the most active volcanoes. Last eruption was not so long ago, in 2008, and in 2010 signs were found that the volcano was becoming active again. The volcano is located southeast of high volcano Tukosmera, but last time erupted in the Pleistocene.
In Sumatra, which is located west of Indonesia, there is a fairly large number of volcanoes - 90, fifteen of which are active. The undersea earthquake in Sumatra is the main cause of the 2004 Asian tsunami.
And by the way, one more interesting fact, regarding Sumatra: about 73 thousand years ago, a giant explosion of the Toba volcano occurred on this island. As a result, a funnel with a diameter of about 100 km was formed at the site of the explosion, and 800 cubic kilometers of dust and ash fell into the atmosphere. This event had, according to scientists, dramatic consequences, since it provoked an 1800-year ice age.
underwater volcano- A type of volcano. These volcanoes are located at the bottom of the ocean.
Most modern volcanoes are located within three main volcanic belts: the Pacific. Mediterranean-Indonesian and Atlantic. As evidenced by the results of studying the geological past of our planet, submarine volcanoes in terms of their scale and volume of ejecta products coming from the bowels of the Earth significantly exceed volcanoes on land. If on land annually from 20-30 volcanic eruptions an average of up to one and a half cubic kilometers of molten magma per year comes out, then during the same time 12-15 times more material erupts from underwater volcanoes.
This happens because underwater volcanoes supply phytoplankton with iron compounds. necessary for photosynthesis. Iron particles, a necessary element for most food chains, are very rare in surface ocean waters. Previously, it was believed that they get there mainly with the waters of rivers and streams. Scientists from the University of Minnesota have proven that most of the iron needed for phytoplankton. can come to the surface from the bottom.
Previously, scientists believed that most of the iron ejected by underwater volcanoes settles to the bottom in inorganic form. Using remotely controlled deep-sea vehicles, the researchers collected particle samples from various volcanically active regions of the Pacific Ocean. Volcanoes create so-called hydrothermal jets - the water in them reaches a temperature of several hundred degrees, but due to the enormous pressure it does not turn into steam. These hydrothermal jets contain a large amount of dissolved substances, including iron ions.
These ions, as the researchers were able to show, further react with organic compounds. dissolved in water, form small particles of submicron size, and are carried away by underwater currents.
Unlike iron, which is more suitable for assimilation by living organisms, ferrous iron Fe. The authors of the article hope that their discovery will lead to a revision of existing opinions about the cycle of iron and carbon in the ocean. It is likely that such a revision will affect experimental work on the "fertilization" of the ocean with iron compounds in order to combat global warming.
Underwater volcanic eruptions
If a reservoir is located above the volcanic chamber, during the eruption, the pyroclastic material is saturated with water and spreads around the chamber. Deposits of this type, first described in the Philippines, were formed as a result of the eruption in 1968 of the Taal volcano. located at the bottom of the lake; they are often represented by thin, wavy layers of pumice. As a result of the activity of underwater volcanoes, islands can form, for example, Reunion, a volcanic island in the Indian Ocean.
It is generally accepted that all major geographical discoveries on Earth have already been made. But in fact, more than half of the surface of our planet remains completely unexplored, primarily the bottom of the ocean. This confirms the discovery made by the last expedition.
A team of Americans and Indonesians on a research vessel studied the anomaly in the sea between Indonesia and the Philippines. The anomaly was identified several years after the analysis satellite imagery Earth.
Only a satellite could notice this, because the depth of the sea in this area is 5-6 kilometers, but from the pictures it immediately became clear that a mountain of a regular conical shape rises above a relatively flat bottom, no less than 1855 meters high.
Alone standing mountain- This underwater volcano . To test this assumption, the Argus deep-sea platform was lowered from the ship, and a small Hercules self-propelled vehicle with a searchlight and a video camera was launched from it.
The frames obtained from a depth of 1855 meters show a pronounced volcanic activity: powerful hot jets carry out a transparent liquid in some places, and white or black "smoke" in others. Yellow and black deposits of molten sulfur are visible near them. And around, in the complete absence sunlight, life is in full swing: a forest of worms sways, shrimp and crustaceans scurry about. All of them receive nutrients and energy from the bowels of the earth.
On land, volcanologists have identified almost all volcanoes that have ever erupted, but in underwater world- at best, every fifth. So the era geographical discoveries continues.
Sources: www.sunhome.ru, www.inokean.ru, relaxic.net, dic.academic.ru, zemlyanin.info
The secret of the Rosicrucians. Protocols of the Elders of Zion
Medveditskaya ridge
Perm anomalous zone
Jerusalem - City of God
Qumran scrolls - the ancient secrets of the Dead Sea
Mount Gladenkaya
Enthusiasm foreign resorts, both summer and winter, imperceptibly left its own scenic spots. And what is very important...
Give a feeling of happiness
Dolls, cars, gadgets, books - this is a far from complete list of what comes to mind when thinking about a gift for a child...
Artificial heart AbioCor
IN modern world filled with stress, mortality from cardiovascular disease occupies a leading position. At the same time, the percentage of people suffering from problems ...
Inca Empire
The Inca Empire has gone into the distant past, its splendor can only be judged by archaeological evidence, which, however, raises more questions than it gives ...
Mutnovskaya GeoPP in Kamchatka
Mutnovskaya GeoPP is the country's largest power plant of this type, which uses the geothermal resources of Kamchatka. The first unit of the Mutnovskaya GeoPP with a capacity of 25 MW...
Asteroid hazard and super-heavy launch vehicles
The fall in February 2013 of a meteorite near Chelyabinsk intensified discussions in Russia on the issue of creating a system to counter asteroids. Asteroid hazard...
Thailand beaches
In Thailand, you will find a huge number of beaches, but we still decided to highlight the most beautiful beaches Thailand. Of course you can...
Man fish from Spain
Inhabitant American city St. Petersburg, Florida put up an unusual lot for the eBay online auction. We are talking about the corpse of a one and a half meter marine ...
Employees of the University of Alberta have found a fundamentally new way to generate electricity from...
underwater volcanism
Rocks of igneous origin - erupted lavas, eruption products, magmatic bodies frozen at a depth - make up more than 2/3 of the volume of the earth's crust. According to seismic studies, the so-called "second layer" of the oceanic crust underlying the sediments is almost entirely composed of underwater basalt lavas.
Thus, volcanoes serve as the main suppliers of matter from the bowels of the Earth to its surface.
Types of underwater volcanism
At present, it is customary to distinguish four main types of modern volcanism of the ocean floor and its framing:
- oceanic rift volcanism, characteristic of mid-ocean ridges,
- volcanism of island arcs and active continental margins,
- volcanism of inland ocean islands,
- volcanism of marginal seas.
Areas of terrestrial and underwater volcanism spatially coincide with seismically active areas and areas of increased heat flow from the Earth's interior. In other words, volcanoes are characteristic of the tectonically most mobile, mechanically weakened zones of the earth's crust.
Oceanic rift volcanism.
Rift volcanism of the oceans is characteristic of rift zones of mid-ocean ridges and is localized at the boundary between moving plates.
Rift zones are dominated by lava eruptions fissure type . It is they who form long chains of volcanic domes 200-300 m high and 2-4 km long with a width of about 0.5 km.
The products of modern underwater volcanic activity in rift zones are mainly represented by basalts homogeneous in chemical composition.
As a result of effusive (outpouring) oceanic rift volcanism, second layer of oceanic crust with an average thickness of about 1.5 km.
Layer 1: formed at a distance from the ROC axis due to slow sedimentation
Layer 2: is formed directly in the rift zone of the MOR due to the intrusion (2С) and outpouring (2А-В) of basalt melt during crustal spreading
Sublayer 3A: is formed under the axial zone of the ROC due to
crystallization of basalt melt along the walls
magma chamber
Sublayer 3B: formed at a small distance from the ROC axis for
account of hydrothermal circulation and serpentinization of part
upper mantle
Volcanism of intra-oceanic islands.
Virtually all islands and seamounts in the interior of the oceans are either active volcanoes or have been in the past. They usually form linear chains of islands and seamounts. Moreover, active volcanism manifests itself at one end of such a chain, and with distance from the active center, the age of volcanoes increases. For example, Hawaiian Islands together with the Imperial underwater ridge form a single chain. This chain stretches from the island of Hawaii to the zone where the Kurile-Kamchatka and Aleutian island arcs converge. Active volcanoes in this chain are found only on the island of Hawaii and in the east of the island of Maui. To the northwest of the island of Hawaii, the age of volcanic rocks gradually increases, reaching 40-43 million years in the place where the Hawaiian Islands and the Imperial underwater ridge converge. If you move north along the Imperial Range, their age will increase even more. The volcanic rocks recovered by a borehole in the northern part of the Imperial Range are older than 72 million years.
The increase in the age of the volcanic rocks of the Hawaiian Ridge was the starting point for the development of the "hot spots" hypothesis. This hypothesis was proposed by J. Wilson and substantiated by W. Morgan. According to Morgan, "hot spots" are fixed and are rounded areas. In these zones mantle jets rising from the mantle reach the Earth's surface. Active underwater volcanoes arise above such mantle jets.
The buildup of volcanoes leads to the formation of volcanic islands. These islands, like on a conveyor belt, move along with the plate lithosphere, moving away from the rift zone. As a result of such movement, the connection between the island and the fixed mantle jet is interrupted, and the volcano ceases its active existence. At the same time, a new volcano grows again above the mantle jet. Thus, the mantle jet, as it were, burns through the moving lithospheric plate, leaving a seam on it in the form of a volcanic ridge, or rather a chain of volcanoes. This creates the effect of migration of volcanism in the direction opposite to the movement of the plate. Bends in the chains of volcanoes have arisen as a result of a change in the direction in which the plate moves.
"Hot spots" can also be located on the border between the sliding plates. In this case, they represent areas of increased volcanic activity within rift zones. Iceland and the Azores are examples of such hotspots. Volcanic ridges formed as a result of the activity of such volcanoes extend in both directions from the rift zone.
In the development of individual volcanoes of the "hot spots" type, one can single out the main period and the period of rejuvenation. The period of rejuvenation usually occurs after a break of several million years.
Island formation. At the first stage, the volcano rises from a depth of 4-5 km and reaches the surface of the ocean. Calm eruptions of lavas are characteristic of this stage. These lavas have a low viscosity and therefore spread over large area, forming gently sloping volcanic structures - shield volcanoes.
When the volcano reaches the surface of the ocean, calm lava outpourings are replaced by volcanic explosions. These volcanic explosions are called hydromagmatic. But as soon as the volcano rises above the ocean level and the erupting melt no longer comes into direct contact with water, the eruptions become calm again. There is an outpouring of lavas of low viscosity. This type of eruptions is called Hawaiian.
The period of rejuvenation is characterized by the outpouring of lava through small side cones on the slopes of shield volcanoes. In the future, the volcanic islands are destroyed and, sinking, turn into atolls.
In the South Pacific Ocean there is a whole belt of island and submarine volcanoes of the "hot spots" type. At least 10 volcanoes in this belt were active during the Pleistocene and Holocene. The belt consists of several closely spaced chains of volcanoes. This volcanic belt is located perpendicular to the rift zone of the East Pacific Rise and is confined to the area where the expansion rate in both directions from the rift zone is maximum. In such areas, convective currents can occur, which is probably the reason for the formation of this belt of “hot spots”.
Volcanism of island arcs and active continental margins.
These volcanoes are the most widely known, as they make up the vast majority of volcanoes that rise above sea level. In addition, their eruptions are often catastrophic. Most of active volcanoes known on Earth (according to the calculations of A. Ritman, about 62%) is located on the periphery of the Pacific Ocean. They form the so-called Pacific "fire" ring.
From the point of view of supporters of the theory of plate tectonics, island arc volcanoes are located on the edge of a plate advancing on the continent. The centers of melting of the magma that feeds the volcanoes are concentrated in the layer where the earthquake sources are located (the seismic focal layer) and, probably, in the upper mantle above the seismic focal layer.
Some island arc volcanoes went through an underwater stage in their early development. An example of modern underwater volcanoes is the Mariana arc.
Both underwater and terrestrial volcanoes of island arcs are characterized by volcanic igneous rocks.
Terrestrial volcanoes of island arcs are characterized by both calm eruptions of the Hawaiian type and catastrophic explosions, as a result of which a huge amount of volcanic material is ejected.
Moreover, the volume of volcanic material delivered to the surface by island arc volcanoes is much lower than that of mid-ocean ridge volcanoes.
Volcanism of marginal seas
It has been poorly studied, since information on the manifestation of volcanic activity is extremely scarce. Shallow-water volcanoes are located on the crust of the continental type.
Paleomagnetism
Lamont scale
Hydrothermal circulation in the oceanic crust, serpentinization of the upper mantle (sublayer 3B), "black smokers"
underwater volcano- A type of volcano. These volcanoes are located at the bottom of the ocean.
Most modern volcanoes are located within the three main volcanic belts: Pacific, Mediterranean-Indonesian and Atlantic. As evidenced by the results of studying the geological past of our planet, submarine volcanoes in terms of their scale and volume of ejecta products coming from the bowels of the Earth significantly exceed volcanoes on land. If on land annually from 20-30 volcanic eruptions an average of up to one and a half cubic kilometers of molten magma per year enters, then during the same time 12-15 times more material erupts from underwater volcanoes. In total, there are about 32 thousand underwater volcanoes.
At the very big volcano The solar system - the Martian Olympus - has a competitor. They found it not on other planets, but on Earth under the water column - at the bottom of the Pacific Ocean. The results of the study by American geophysicists were published in an article in the journal Nature Geoscience.
A volcano the size of Britain has been discovered in the northwestern Pacific Ocean, on a massif Tamo, where several tectonic plates. The results of drilling of the bottom in this area showed that it consists entirely of lava deposits, but so far it has not been clear whether Tamo is a single volcano or there were several eruption points. It turned out that the lava flows came from one point, which means that there is a single central vent.
"Before that, we were not sure that we were dealing with a single volcano capable of growing to such a size. Now we are sure," said William Sager, lead author of the study. "Thus, the Tamo massif is the largest shield volcano ever discovered on Earth," he added.
Tamo, which belongs to the class of shield volcanoes, very large in area and with gentle slopes, reaches 4 km in height, and its diameter is approximately 625 kilometers. For comparison: the diameter of the largest Mauna loa volcano does not even reach ten kilometers. Tamo formed about 145 million years ago and has not erupted for 140 million years.
The discovery will allow scientists to learn more about how much magma can accumulate underground and slosh to the surface. Experts also noted that Tamo's shape is different from other underwater volcanoes, and expressed the hope that its study will give them a clue to understanding how such massive volcanic formations are formed.
Scientists have discovered 12 previously unknown underwater volcanoes in Antarctica. The authors spoke about their discovery at the 11th International Symposium on Antarctic Studies. Briefly, the essence of the report is given in a press release on the website of the British Antarctic Survey.
The researchers studied the bottom topography in the area of the South Sandwich Islands from 2007 to 2010. With the help of sonars, they were able to detect new volcanoes - the height of some of them reaches three kilometers. Seven of the found volcanoes are active and visible above the surface of the water - they look like a chain of islands. In addition, scientists discovered a funnel with a diameter of about five kilometers, which remained after the destruction of one of the volcanoes.
The authors note that on this moment specialists know very little about the characteristics of submarine volcanoes at high latitudes and their influence on the biology of these areas. Active volcanoes heat the water around them and can thus create favorable conditions for the habitat of many living organisms.
volcanic island- an island formed as a result of volcanic activity at the bottom of the sea.
In practice, a series of volcanic islands usually arise, which are the upper part of the volcanic ridge, located with a certain pattern (Hawaiian Islands, Canary Islands, Kurile Islands etc.)
The island is the top of an underwater volcano, raised above the surface of the ocean. The formation of the island occurs in several phases.
Darwin suggested that growth coral islands(atolls) occurs in the process of gradual subsidence of volcanic islands. He noted that atolls are usually formed by fouling of a volcanic island. coral reef forming an annular belt.
Iceland is the largest volcanic island. The second largest island of Hawaii ( Big Island). In third place is the island of Bali. In Russia, the largest volcanic island is Iturup. The largest island crater - 4.5 km in diameter - has Kilauea in the Hawaiian archipelago.
End of work -
This topic belongs to:
Volcanism on earth and its geographical consequences
Volcanoes are a geological formation above channels and cracks in the earth's crust through which lava erupts hot gases of ash and water to the surface.
If you need additional material on this topic, or you did not find what you were looking for, we recommend using the search in our database of works:
What will we do with the received material:
If this material turned out to be useful for you, you can save it to your page on social networks:
In the light of recent events in Iceland, the topic of volcanoes has become extremely popular and, of course, keeping up with the times, we decided to make a selection about underwater volcanoes. After all, terrestrial, after becoming famous volcano Eyyafyatlayokudl, you will not surprise anyone.
Coast of Tonga
Thirty kilometers from Falcon Island is an underwater volcano called Hunga Tonga-Hunga Haʻapai or Hunga-Tonga for short. The volcano is located 100 kilometers from an area with high seismological activity. It should be noted that relatively recently, in March 2009, the volcano began throwing pillars of smoke and ash thousands of feet above the ocean.
Hawaii
Loihi - underwater active volcano, located 35 kilometers southeast of the island of Hawaii on the slope of Mauna Loa, the largest shield volcano in the world. Loihi is one of the youngest volcanoes Hawaiian ridge. It was first discovered in 1970, but began to act later - the first activity was noted in 1996.
Iceland
They did not expect? Another young volcano formed in 1973 as a result of an eruption on the outskirts of the city of Heimaey. The eruption of Eldfell was a complete surprise for both scientists and local residents. Emissions from the volcano continued until July 1974, after which Eldfell lost activity. New eruptions, according to experts, are unlikely. The height of Eldfell is about 200 meters.
Vanuatu
We are talking about the volcano Yasur (Yasur). This is a very old volcano, which scientists believe formed about a million years ago, but was discovered only in 1774, when the first documented eruption occurred. Yasur is also considered one of the most active volcanoes. The last eruption was not so long ago, in 2008, and in 2010 there were signs that the volcano was becoming active again. The volcano is located southeast of the higher volcano Tukosmera, which last erupted in the Pleistocene.
Sumatra
In Sumatra, which is located west of Indonesia, there is a fairly large number of volcanoes - 90, fifteen of which are active. The undersea earthquake in Sumatra is the main cause of the 2004 Asian tsunami.
And, by the way, one more interesting fact about Sumatra: about 73 thousand years ago, a giant explosion of the Toba volcano occurred on this island. As a result, a funnel with a diameter of about 100 km was formed at the site of the explosion, and 800 cubic kilometers of dust and ash fell into the atmosphere. This event had, according to scientists, dramatic consequences, since it provoked an 1800-year ice age.
Based on Wikipedia, the free encyclopedia
