6533b7d2fe1ef96bd125e8fb

RESEARCH PRODUCT

Maars of the Westeifel, Germany

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description

Within the Westeifel Volcanic Field 27% of the 250 Quaternary eruptive centers are maars. Maars form as a result of a highly explosive interactive process between rising melt and groundwater. In the Westeifel, probably thermal water plays an important role for the productive phreatomagmatic interaction process and, con-sequently, the high number of maars. The Westeifel maars show all transitions to scoria cones. Only the youngest maars are filled by a maar lake or a raised bog, and are well preserved. The older maars show a low diameter to depth ratio. Nearly one third of the Westeifel maars were formed during the Weichselian glaciation period. The isostatic movements during the increasing and decreasing glaciation generated tectonic stress in front of the ice cap and, probably, caused the inten-sive volcanic activity during the last glaciation. This assumed to be the reason why for the last 10 000 years BP (Ulmen maar activity) no volcanic activity has happened.