The Booser Doppelmaar ("Double Maar of Boos") comprises two

maar A maar is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption (an explosion which occurs when groundwater comes into contact with hot lava or magma). A maar characteristically fills with water to form a relatively shallow ...

s that have silted up and, today, form shallow depressions in the countryside. They lie on the territory of the village of Boos (in the collective municipality of

Vordereifel Vordereifel is a ''Verbandsgemeinde'' ("collective municipality") in the district of Mayen-Koblenz, in Rhineland-Palatinate, Germany. It is situated on the eastern edge of the Eifel, west of Mayen Mayen () is a town in the Mayen-Koblenz, Mayen-Ko ...

), a few hundred metres west of the village itself. The two maars were formed 10,150 to 14,160 years ago and belong to the

Quaternary The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the ...

volcano field of the Volcanic Eifel.Volcanic Eifel in the sense of a natural historical space or a region, not in the sense of a natural regional unit. From a

natural region A natural region (landscape unit) is a basic geographic unit. Usually, it is a region which is distinguished by its common natural features of geography, geology, and climate. From the ecological point of view, the naturally occurring flora and ...

perspective it lies in the south of the Hohe Acht Upland (which belongs to the natural regional major unit of the Eastern High Eifel), ca. 7.8 km south (more precisely half west-by-south or 185.625º) of the summit of the Hohe Acht.

The maars

The two maars form large, circular basins surrounded by

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock co ...

embankments that lie on a line running west-southwest to east-northeast and thus follow the

Variscan The Variscan orogeny, or Hercynian orogeny, was a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica (Laurussia) and Gondwana to form the supercontinent of Pangaea. Nomenclature The name ''Variscan ...

strike Strike may refer to: People *Strike (surname) * Hobart Huson, author of several drug related books Physical confrontation or removal *Strike (attack), attack with an inanimate object or a part of the human body intended to cause harm * Airstrike, ...

of the terrain. The west-southwestern maar has a diameter of about 700 metres and is between 30 and 60 metres deep; its north-northeastern counterpart is between 650 and 700 metres across and from 50 to 87 metres deep. The two hollows are very wet, so that there are still places that are permanently under water. These wet areas were formerly used as

fish pond A fish pond or fishpond is a controlled pond, small artificial lake or retention basin that is stocked with fish and is used in aquaculture for fish farming, for recreational fishing, or for ornamental purposes. Fish ponds are a classical g ...

s, but later silted up and became meadows and arable fields. Today there is a fish pond again in the west-southwestern maar known as the Booser Weiher. In the vicinity of the maars are tuff pits in which the volcanic tuff, formed during the eruption of the maars, was mined.

Formation and rocks

Volcanism Volcanism, vulcanism, volcanicity, or volcanic activity is the phenomenon where solids, liquids, gases, and their mixtures erupt to the surface of a solid-surface astronomical body such as a planet or a moon. It is caused by the presence of a he ...

in the Eifel began about 600,000 years ago and led to the formation of numerous volcanic landforms. What was probably the last eruption, which led to the formation of the Ulmener Maar, was about 11,000 years ago. Within those timeframes the Boos maars belong to the youngest formations in the Volcanic Eifel. C¹⁴ dating of rocks from the maars as well as of organic material have suggested an age of 14,160 years for the eastern maar. The tuffs, which have been dated to 10,150 years ago, cannot be positively associated with the formation of the two maars. The tuffs contain

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 ...

bombs A bomb is an explosive weapon that uses the Exothermic process, exothermic reaction of an explosive material to provide an extremely sudden and violent release of energy. Detonations inflict damage principally through ground- and atmosphere-tra ...

with host rock and large

olivine The mineral olivine () is a magnesium iron Silicate minerals, silicate with the chemical formula . It is a type of Nesosilicates, nesosilicate or orthosilicate. The primary component of the Earth's upper mantle (Earth), upper mantle, it is a com ...

crystals. The tuffs consist partly only of

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma (sometimes colloquially but incorrectly referred to as ''lava'') is found beneath the surface of the Earth, and evidence of magmatism has also ...

tic crystals (crystal tuffs) and contain broken pieces of wehrlite and

syenite Syenite is a coarse-grained intrusive igneous rock with a general composition similar to that of granite, but deficient in quartz, which, if present at all, occurs in relatively small concentrations (< 5%). It is considered a lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...

have intruded into the tuffs. In the immediate vicinity of the Booser Doppelmaar there is a total of eight

cinder cone A cinder cone or scoria cone is a steep, volcanic cone, conical landform of loose pyroclastic rock, pyroclastic fragments, such as volcanic ash, clinkers, or scoria that has been built around a volcanic vent. The pyroclastic fragments are forme ...

s, that were formed more or less simultaneously about 35,000 years ago. A lava stream flowed from one of these volcanic cones westwards reaching the valley of the Nitz.

Nature reserve and Volcano Park station

The two maars lie within the "Booser Maar" Nature Reserve, which with 152 or 157.7136 haExtract from Osiris Rheinland-Pfalz about the NSG-7137-004 Booser Maar
in a

Rhineland-Palatinate Rhineland-Palatinate ( , ; ; ; ) is a western state of Germany. It covers and has about 4.05 million residents. It is the ninth largest and sixth most populous of the sixteen states. Mainz is the capital and largest city. Other cities are ...

website. Retrieved 7 May 2015. one of the largest

nature reserves A nature reserve (also known as a wildlife refuge, wildlife sanctuary, biosphere reserve or bioreserve, natural or nature preserve, or nature conservation area) is a protected area of importance for flora, fauna, funga, or features of geolog ...

. In the reserve, on the hill of the Schneeberg (on the embankment on the eastern side of the east-northeastern maar) is the Eifel Tower. The reserve is also a station in the Volcano Park (in

Mayen-Koblenz Mayen-Koblenz is a district (''Kreis'') in the north of Rhineland-Palatinate, Germany. Neighboring districts are (from north clockwise) Ahrweiler (district), Ahrweiler, Neuwied (district), Neuwied, Westerwaldkreis, district-free Koblenz, Rhein-Lahn ...

), VULKANPARK with its head office in

Koblenz Koblenz ( , , ; Moselle Franconian language, Moselle Franconian: ''Kowelenz'') is a German city on the banks of the Rhine (Middle Rhine) and the Moselle, a multinational tributary. Koblenz was established as a Roman Empire, Roman military p ...

Footnotes

References

Literature

* Wilhelm Meyer: ''Geologie der Eifel.'' Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, 1986, .

.
Booser Doppelmaar tour
nbsp;– Eifel Dream Footpath of th
Dream Footpath Project Office
of the Rhine-Moselle-Eifel Tourism Office (REMET) – Tourist Association of

.
Booser Doppelmaar
nbsp;– station in the Volcano Park (in

), VULKANPARK, head office in