The Zuidwal volcano is an extinct

volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...

in the

Netherlands , Terminology of the Low Countries, informally Holland, is a country in Northwestern Europe, with Caribbean Netherlands, overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Nether ...

at more than below ground under the

Wadden Sea The Wadden Sea ( ; ; or ; ; ; ) is an intertidal zone in the southeastern part of the North Sea. It lies between the coast of northwestern continental Europe and the range of low-lying Frisian Islands, forming a shallow body of water with tida ...

, between Harlingen and

Vlieland (; ) is a municipality and island in the northern Netherlands. The municipality of Vlieland is the second most sparsely populated municipality in the Netherlands, after Schiermonnikoog. Vlieland is one of the West Frisian Islands, lying in t ...

, just south west of the island Griend. The volcano was last active during the late

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. ...

, (about 160 - 148 Ma ago) and has since been covered by about of

sedimentary rock Sedimentary rocks are types of rock (geology), rock formed by the cementation (geology), cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or de ...

, most of it

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...

and

sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...

from the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

Discovery

The volcano was discovered in 1970 when the French oil company

Elf Aquitaine Elf Aquitaine is a French brand of oils and other motor products (such as brake fluids) for automobiles and trucks. Elf is a former petroleum company which merged with TotalFina to form "TotalFinaElf". The new company changed its name to Total ...

was doing test drills in the Wadden Sea, hoping to find a gas field that a

seismic Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes (or generally, quakes) and the generation and propagation of elastic ...

survey had indicated. To their surprise they hit

volcanic rock Volcanic rocks (often shortened to volcanics in scientific contexts) are rocks formed from lava erupted from a volcano. Like all rock types, the concept of volcanic rock is artificial, and in nature volcanic rocks grade into hypabyssal and me ...

beneath the

reservoir rock A petroleum reservoir or oil and gas reservoir is a subsurface accumulation of hydrocarbons contained in porous or fractured rock formations. Such reservoirs form when kerogen (ancient plant matter) is created in surrounding rock by the presenc ...

, which turned out to be an extinct volcano. The gas field went in production in 1988 and is still producing

gas Gas is a state of matter that has neither a fixed volume nor a fixed shape and is a compressible fluid. A ''pure gas'' is made up of individual atoms (e.g. a noble gas like neon) or molecules of either a single type of atom ( elements such as ...

. Another clue indicating the presence of the volcano was the temperature. While the usual temperature at that depth is about , they found .

Volcano

The volcano has a height of approximately and a circumference of several kilometers. The volcano was formed about 160 million years ago, during a time of orogenesis on the European continent. The eruptions were short and severe with heavy explosions. This, along with the mineral composition, points to volcanic activity as a result of

subduction Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second p ...

far away from the volcano. During the Cimmerian Orogeny, the Cimmerian Plate collided with

Kazakhstania Kazakhstania (), the Kazakh terranes, or the Kazakhstan Block, is a geological region in Central Asia which consists of the area roughly centered on Lake Balkhash, north and east of the Aral Sea, south of the Siberian craton and west of the Alta ...

, sending shock waves through the Eurasian Plate, resulting in volcanism. The volcano is covered by layers of sandstone from the early Cretaceous that act as

for the gas. The seal rock consists of shale. The volcanic rock is magnetic, creating a

magnetic anomaly In geophysics, a magnetic anomaly is a local variation in the Earth's magnetic field resulting from variations in the chemistry or magnetism of the rocks. Mapping of variation over an area is valuable in detecting structures obscured by overlying ...

References

External links

Vulkaan in Nederland
– Wetenschap24.nl {{DEFAULTSORT:Zuidwal Volcano Volcanoes of the Netherlands Wadden Sea Jurassic volcanoes Extinct volcanoes of Europe Magnetic anomalies Stratovolcanoes

Discovery

Volcano

See also

References

External links