The Dreiser Weiher near

Dreis-Brück Dreis-Brück is an ''Ortsgemeinde'' – a municipality belonging to a ''Verbandsgemeinde'', a kind of collective municipality – in the Vulkaneifel district in Rhineland-Palatinate, Germany. It belongs to the ''Verbandsgemeinde'' of Daun, whose s ...

in the vicinity of

Daun Daun is a town in the Vulkaneifel district in Rhineland-Palatinate, Germany. It is the district seat and also the seat of the ' of Daun. Geography Location The town lies in the , a part of the Eifel known for its volcanic history, geogra ...

in the German state of

Rhineland-Palatinate Rhineland-Palatinate ( , ; german: link=no, Rheinland-Pfalz ; lb, Rheinland-Pfalz ; pfl, Rhoilond-Palz) 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 ...

is a tub-shaped

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 ...

in the

Eifel The Eifel (; lb, Äifel, ) is a low mountain range in western Germany and eastern Belgium. It occupies parts of southwestern North Rhine-Westphalia, northwestern Rhineland-Palatinate and the southern area of the German-speaking Community of ...

mountains. It is up to 1,360 metres long and 1,160 metres wide. It is the second largest maar in the Eifel.

Formation

The dry maar is located on a hillside and belongs 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). It follows the Neogene Period and spans from 2.58 million years ...

volcano A volcano is a rupture 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 often found where tectonic plates are ...

es of the

West Eifel The West Eifel (german: Westeifel) refers to that part of the Eifel mountains in Germany that is centred on the town of Prüm and reaches as far as the border with Belgium and Luxembourg. It is not geographically precisely defined however, overla ...

. It is surrounded by a crater rim of between 36 and 120 metres high. From the analysis of volcanic

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 cont ...

f, which were ejected from the maar during an eruption, and from

geomagnetic Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from the Sun. The magnetic fi ...

measurements, five tuff fields and four volcanic centres on the edge of the bowl were identified. In the centre of the maar an eruption site was identified, hence the maar is probably an eruption funnel. The tuffs of the Dreiser Weiher lies above the depositions of the surrounding volcanoes, the maar is thus younger than the others. An exact date for the formation of the maars using

pollen analysis Palynology is the "study of dust" (from grc-gre, παλύνω, palynō, "strew, sprinkle" and ''-logy'') or of "particles that are strewn". A classic palynologist analyses particulate samples collected from the air, from water, or from deposits ...

could not be done for the Dreiser Weiher since there is no bog here. So-called olivinite bombs, from the time when the maar was formed, occur in the vicinity. Due to the many, mainly rare minerals and rocks that occur here, the Dreiser Weiher achieved scientific renown early on. It is not clear whether the material here is from the

earth's mantle Earth's mantle is a layer of silicate rock between the crust and the outer core. It has a mass of 4.01 × 1024 kg and thus makes up 67% of the mass of Earth. It has a thickness of making up about 84% of Earth's volume. It is predominantly sol ...

or whether it is due to

magmatic differentiation In geology, igneous differentiation, or magmatic differentiation, is an umbrella term for the various processes by which magmas undergo bulk chemical change during the partial melting process, cooling, emplacement, or eruption. The sequence of (u ...

. Discussions are still ongoing in scientific circles about the origin of the material.

History of use

The former maar lake was drained in the early 19th century. Today its basin is drained by artificial ditches into the Ahbach stream. In the Dreiser Weiher is a commercially used

mineral spring Mineral springs are naturally occurring springs that produces hard water, water that contains dissolved minerals. Salts, sulfur compounds, and gases are among the substances that can be dissolved in the spring water during its passage underg ...

, the

Nürburg Spring Nürburg () is a town in the German district of Ahrweiler, in the state of Rhineland-Palatinate. It is also the name of the local castle, Nürburg Castle, which was built in the High Middle Ages. The name is derived from Latin ''niger'', meaning ...

. The Dreiser Weiher is part of the nature reserve of ''Dreiser Weiher mit Döhmberg und Börchen''. The Dreiser Weiher is a popular area for

paraglider Paragliding is the recreational and competitive adventure sport of flying paragliders: lightweight, free-flying, foot-launched glider aircraft with no rigid primary structure. The pilot sits in a harness or lies supine in a cocoon-like 'po ...

s with exceptionally good thermal conditions all year round.

Literature

* Werner P. D´hein: ''Vulkanland Eifel. Natur- und Kulturführer, mit 26 Stationen der "Deutschen Vulkanstraße"''. Gaasterland-Verlag, Düsseldorf 2006, , . * Wilhelm Meyer: ''Geologie der Eifel''. Schweizerbathsche Verlagsbuchhandlung, 3. Auflage, Stuttgart 1994, . {{Coord, 50, 15, 51.6, N, 06, 46, 38.4, E , type:waterbody _region:DE-RP Maars of the Eifel Vulkaneifel