The Zuidwal volcano is an extinct

volcano A volcano is a rupture in the Crust (geology), crust of a Planet#Planetary-mass objects, planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and volcanic gas, gases to escape from a magma chamber below the surface. On Ear ...

in the

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

at more than below ground under the Wadden Sea, between Harlingen and

Vlieland Vlieland (; fry, Flylân) 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 Frisia ...

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

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

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

sedimentary rock Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

, most of it shale and

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

from the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

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 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 presence ...

that a

seismic Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other ...

survey had indicated. To their surprise they hit

volcanic rock Volcanic rock (often shortened to volcanics in scientific contexts) is a rock formed from lava erupted from a volcano. In other words, it differs from other igneous rock by being of volcanic origin. Like all rock types, the concept of volcanic ...

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 presence ...

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

gas Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma). A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or ...

. 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 Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent boundary, convergent plate margin when plate motion compresses the margin. An ''orogenic belt'' or ''orogen'' develops as the compressed plate crumpl ...

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 far away from the volcano. During the Cimmerian Orogeny, the

Cimmerian Plate Cimmeria was an ancient continent, or, rather, a string of microcontinents or terranes, that rifted from Gondwana in the Southern Hemisphere and was accreted to Eurasia in the Northern Hemisphere. It consisted of parts of present-day Turkey, Ir ...

collided with

Kazakhstania Kazakhstania ( kk, Qazaqstaniya), 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 ...

, sending shock waves through the

Eurasian Plate The Eurasian Plate is a tectonic plate that includes most of the continent of Eurasia (a landmass consisting of the traditional continents of Europe and Asia), with the notable exceptions of the Indian subcontinent, the Arabian subcontinent and ...

, 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 Magnetic anomalies Stratovolcanoes

Discovery

Volcano

See also

References

External links