Volcanism of the Eifel,
Germany Region

James S. Aber
GO 326/ES 767

Introduction

The Eifel volcanic field is located in western Germany, near the Rhine River—see handout maps. This region has been subject to various Cenozoic tectonic events. The Rhenish Shield, a large lithospheric block, experienced several episodes of uplift, while the Rhine Graben formed as a continental rift zone. The Eifel volcanic zone is separated into two portions--east and west, which developed during the Quaternary uplift of the Rhenish Shield. The volcanic deposits are dominated by potassium-rich, silica-poor scoria cones, which are typical for intraplate, continental settings (van den Bogaard 1995). Many xenoliths are included in Eifel volcanic deposits; they were derived from lower crustal and upper mantle sources.

The West Eifel Volcanic Field (WEVF) is about 600 km² and contains around 240 individual volcanoes. It is more mafic (Mg-Fe rich), less silicic, and has larger peridotite xenoliths compared to the smaller East Eifel Volcanic Field (EEVF). The EEVF has about 100 volcanoes, including Laacher See, the youngest volcano (13,000 years old). Four well-defined eruptive phases are documented along with older volcanic eruptions in the Eifel region (van den Bogaard 1995).

  1. Rieden volcanic complex – 380,000 to 430,000 years old in the WEVF. It consists of plagioclase-free fallout, flow deposits, and scoria cones in various compositional types (leucite-phonolite, nephelinite, leucitite).

  2. Southeastern sector of EEVF – around 215,000 to 225,000 years old. Basaltic (basanite and tephrite) scoria cones.

  3. Niedermendiger lava flow – between 100,000 to 150,000 years old. Major basaltic (tephrite) lava flow along with lesser alkalic (phonolite) eruptions in the EEVF.

  4. Laacher See eruption – about 13,000 years ago. Major eruption of alkalic (phonolite) tephra and pumice at the Laacher See volcano in the EEVF. Volume of erupted magma was approximately 5 km³, which equals or exceeds all mafic eruptions in the WEFV.

Photo Gallery

The following photographs were taken in connection with an INQUA field trip on Quaternary volcanism in the Eifel region of western Germany. The trip was organized and led by Paul van den Bogaard (1995). Click on each photo for a full-size display; all photos © J.S. Aber.

Wannenköpfe scoria cone. Panoramic view showing a complete section across the scoria cone, as exposed in an active quarry. Basaltic (basanite-tephrite) volcano in the southeastern sector EEVF.
Wannenköpfe scoria cone. Closeup view of vesicular scoria fragments. Pocket knife for scale.
Wannenköpfe scoria cone. Flank of scoria cone in which clay dikes (red) can be seen. These dikes were derived from underlying sediments that were mobilized by high-pressure ground water. Note people standing in front of a large dike.
Eppelsberg scoria cone. This cone contains spectacular growth faults. These faults formed as scoria accumulated on flanks of the volcano. Note people at bottom for scale. Typical of hybrid scoria cones in the EEVF; dated at 223,000 years old.
Eppelsberg scoria cone. Finely bedded tephra layers near the top of the cone preserve tree molds. These near-vertical hollows formed when tephra accumulated around tree trunks.
Rieden tephra deposits in the WEVF. Consolidated tuff was deposited as phonolitic pumice (highly vesicular glass) from fiery ash clouds. Zeolite minerals were created by later alteration of the pumice in contact with ground water.
Closeup view of the Rieden tephra (tuff). This rock has been quarried for centuries for building stone, and the rock forms an important aquifer in the surrounding basin. Pocket knife for scale.
Tephra layers in rim of Leyendecker volcano, WEVF. Note the uniform layering, fining upward texture, and dip away from the volcanic vent (located to right of view). The tephra contains many xenoliths (next photo).
Selection of peridotite xenoliths from the Leyendecker tephra. These fragments are composed of olivine derived from the upper mantle. Pocket knife for scale.
Niedermendiger basalt lava flow exposed in an old quarry. Columnar jointing is displayed prominently. The lava flow has an average thickness of 12 m and an areal extent of 1.4 km². The basalt was quarried in medieval time for manufacturing mill stones; it is quarried today for construction material.
Closeup view of the Niedermendiger basalt showing numerous xenolith inclusions. Pocket knife for scale.
Overview of Laacher See volcanic crater with lake in center and tephra ring visible on the far horizon. Laacher See was the latest eruption in the Eifel volcanic zone. It was a Plinian style eruption—extremely explosive degassing of the magma chamber.
Laacher See tephra exposed in a quarry. The tephra is rich in pumice and glassy ash shards. Tephra from the Laacher See eruption is found throughout central Europe, where it forms an important marker bed within late glacial sediments and archeologic sites of Allerød age.
A portion of the volcanological map of the East Eifel region. The lake near map center occupies the caldera of the Laacher See volcano, which erupted about 13,000 years ago. The blue region (near map bottom) is the Niedermendiger lava flow, which formed between 100,000 to 150,000 years ago. Green hills around Laacher See are older scoria cones, erupted 190,000 to 225,000 years ago. Taken from Bogaard and Schmincke (1990).

Tectonic Setting

The Eifel volcanic region is closely associated with the Rhine Graben, a continental rift zone of Cenozoic age—see handout maps. The Rhine Graben became active in the Eocene, and fault movements intensified during the Miocene. Major basaltic eruptions of the Vogelsburg vicinity also took place in the Miocene, when a "Dead Sea" type situation existed in the rift valley. Since the Miocene, tectonic activity of the Rhine Graben and other rift zones of western Europe has continued at a lower level—minor fault movement, occasional earthquakes, and Quaternary volcanism at Eifel. Cenozoic continental rifting of western Europe thus appears to have "failed" or been arrested from continued development. Eifel is probably not a hot-spot manifestation, as the volcanism does not show a consistent migration in location through time.

Related website

References

Return to tectonics syllabus.
GO 326/ES 767 © J.S. Aber (2012).