The Strýtan vent field is a

hydrothermal vent Hydrothermal vents are fissures on the seabed from which geothermally heated water discharges. They are commonly found near volcanically active places, areas where tectonic plates are moving apart at mid-ocean ridges, ocean basins, and hot ...

field located in the northern

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

at a depth of . It is located within Iceland's northern fjord Eyjafördur near

Akureyri Akureyri (, ) is a town in northern Iceland, the country's fifth most populous Municipalities of Iceland, municipality (under the official name of Akureyrarbær , 'town of Akureyri') and the largest outside the Capital Region (Iceland), Capital R ...

. As of 2024, it is the only known

alkaline In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The ...

hydrothermal vent field hosted on

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

rock. It is a popular site for divers.

History

The oldest reports of the Strýtan vent field date back hundreds of years to fishermen using dive weights. However, the

Icelandic Coast Guard The Icelandic Coast Guard (, or simply ) is the Icelandic defence service responsible for search and rescue, maritime safety and security surveillance, national defense, and law enforcement. The Coast Guard maintains the Iceland Air Defence ...

did not detect the vent chimneys and declared them as non-existent in 1987. Only in 1997 was the Strýtan vent field reported by divers Erlendur Bogason and Árni Halldósson and identified as a real geologic feature. It was also explored by GEOMAR in 1997, using the HOV ''JAGO'', a German research

submersible A submersible is an underwater vehicle which needs to be transported and supported by a larger ship, watercraft or dock, platform. This distinguishes submersibles from submarines, which are self-supporting and capable of prolonged independent ope ...

. In 2001, Strýtan was designated as a protected Icelandic preserve.

Geology and location

Strýtan is in the vicinity of the Dalvík Lineament, which connects to the Eyjafjarðaráll Rift which extends to the Kolbeinsey Ridge. Strýtan is among the shallowest vent fields known and is among the few coastal hydrothermal systems known. The vent field is composed of three primary venting sites. Big Strýtan, Arnarnesstrýtur (sometimes referred to as Little Strýtan), and Hrisey. The Big Strýtan cone is composed prodominantly of

anhydrite Anhydrite, or anhydrous calcium sulfate, is a mineral with the chemical formula CaSO4. It is in the orthorhombic crystal system, with three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with the ...

and

saponite Saponite is a trioctahedral mineral of the smectite group. Its chemical formula is . It is soluble in sulfuric acid. It was first described in 1840 by Lars Fredrik Svanberg, Svanberg. Varieties of saponite are griffithite, bowlingite and sobotk ...

, with some chimneys as tall as . Samples from the site indicate an extensive series of mineral phases within the mounds with fibrous, crystalline minerals establishing pore spaces for fluids to travel through.

Geochemistry

Unlike

Lost City In the popular imagination, a lost city is a real, once-prosperous and well-populated area of human habitation that fell into terminal decline and whose location was later forgotten. Lost City, The Lost City, or Lost Cities may also refer to: Pl ...

, another alkaline field to the south in the Atlantic, Strýtan is hosted on 6-12 MA

Mid-ocean ridge A mid-ocean ridge (MOR) is a undersea mountain range, seafloor mountain system formed by plate tectonics. It typically has a depth of about and rises about above the deepest portion of an ocean basin. This feature is where seafloor spreading ...

basalts and recharge is primarily from freshwater contributions of terrestrial origin, with fluid stable isotopes ( ''δ''¹⁸O, δ²H) and

radiocarbon Carbon-14, C-14, C or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic matter is the basis of the radiocarbon dating method pioneered by Willard Libby and coll ...

matching that of terrestrial reservoirs. Venting fluids are moderate at a temperature of ~ and are highly alkaline at a pH of about 10.2. Venting is most profuse at Big Strýtan, where the discharge rate is estimated at 50 meters per second. Silica, magnesium, calcium, and oxygen are abundant in venting fluids and salinity is 0.5 - 14% of that of seawater. Silicon dioxide concentrations are elevated relative to seawater and consume magnesium in the

precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls from clouds due to gravitational pull. The main forms of precipitation include drizzle, rain, rain and snow mixed ("sleet" in Commonwe ...

of tall saponite chimneys. A 2024 study found

brucite Brucite is the mineral form of magnesium hydroxide, with the chemical formula Magnesium, Mg(hydroxyl, OH)2. It is a common alteration product of periclase in marble; a low-temperature hydrothermal Vein (geology), vein mineral in metamorphosed li ...

within the chimneys at Strýtan, suggesting the possibility of ferrobrucite (containing iron) and therefore

prebiotic chemistry Abiogenesis is the natural process by which life arises from non-living matter, such as simple organic compounds. The prevailing scientific hypothesis is that the transition from non-living to living entities on Earth was not a single even ...

reactions like those seen at Lost City.

Biology

Strýtan has an abundance of mussels, bryozoans, sponges, hydroids, brittlestars, and polychete worms. '' Metridium'' anemones, nudibranchs, and

sea spider Sea spiders are marine arthropods of the class (biology), class Pycnogonida, hence they are also called pycnogonids (; named after ''Pycnogonum'', the type genus; with the suffix '). The class includes the only now-living order (biology), order P ...

s have also been reported.

History

Geology and location

Geochemistry

Biology

References

See also