Discovery of the first Quaternary maar in the Bohemian Massif, Central Europe, based on combined geophysical and geological surveys

0330220 - GFÚ 2010 RIV NL eng J - Journal Article
Mrlina, Jan - Kämpf, H. - Kroner, C. - Mingram, J. - Stebich, M. - Brauer, A. - Geissler, W.H. - Kallmeyer, J. - Matthes, H. - Seidl, Michal
Discovery of the first Quaternary maar in the Bohemian Massif, Central Europe, based on combined geophysical and geological surveys.
Journal of Volcanology and Geothermal Research. Roč. 182, č. 1-2 (2009), s. 97-112. ISSN 0377-0273. E-ISSN 1872-6097
R&D Projects: GA AV ČR IAA300460602
Institutional research plan: CEZ:AV0Z30120515
Keywords : Eger Rift * Quaternary maar volcanism * geophysical survey * Saalian lake sediments * volcanic hazard potential
Subject RIV: DC - Siesmology, Volcanology, Earth Structure
Impact factor: 1.921, year: 2009

Based on results of previous investigations of tephra-tuff volcaniclastic deposits and a geophysical survey in the surroundings of the Železná hůrka Quaternary volcano, West Bohemia, we performed detailed geophysical surveys using gravimetry, magnetometry and electrical conductivity techniques. Striking anomalies were revealed in a morphological depression near Mýtina,West Bohemia, as a strong evidence of the assumed maar-diatreme structure. The sharp isometric gravity low of−2.30 mGal, aswell as the corresponding positive magnetic anomaly of 200 nT with a negative rim on its northern side indicate a steeply dipping geological body of low density and containing magnetic rocks/minerals. Magnetic survey also showed pronounced local anomalies outside the depression that can reflect relicts of the tephra rim of the maar.
Permanent Link: http://hdl.handle.net/11104/0176062