Isolated alkaline basalt occurrences in the northern Spessart, Germany: Outposts of the Early Miocene Vogelsberg shield volcano?

Okrusch M, Schuessler U, Van Den Bogaard P, Koglin N, Brätz H, Lorenz J, Karbusicka C, Spiegl T (2020)

Publication Type: Journal article

Publication year: 2020

Journal

Neues Jahrbuch für Mineralogie-Abhandlungen Schweizerbart und Borntraeger

Book Volume: 196

Pages Range: 199-219

Journal Issue: 3

DOI: 10.1127/njma/2020/0194

Abstract

Four isolated occurrences of Tertiary volcanic rocks in the northern Spessart at Beilstein, Hoher Berg, Madstein and Kasselgrund are relics of volcanic vents or dikes. They display alkaline basalts (s.l.) with mainly trachybasaltic composition, which, from nonnative mineral contents, may be designated as nepheline-bearing alkali-olivine basalts and basanites. In part, centimetre-sized xenoliths of spinel lherzolite occur. According to Ar-Ar dating, the alkaline basalts (s.l.) from Kasselgrund have erupted at 18.1 +/- 0.3 or 19.3 +/- 0.4 Ma, those of Hoher Berg between c. 18 and c. 21 Ma. These ages correspond to the Vogelsberg eruption stage I.A slightly younger Ar-Ar age of 16.8 +/- 0.3 Ma was recorded for the Beilstein basalt, which is in chronological accordance to the turn of Vogelsberg eruption stages II and III. Samples of all four occurrences reveal major and trace element compositions, which are different from those of the Vogelsberg basalts. Compositions of basalts of the stage III from Vogelsberg coincide most with the Spessart basalts. This signals a special position of the northern Spessart volcanic rocks either as a discrete spatial part of the Vogelsberg volcanic suite or as smaller, independent eruption centres.

Authors with CRIS profile

Helene Brätz Geozentrum Nordbayern

Involved external institutions

Julius-Maximilians-Universität Würzburg DE Germany (DE) GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel DE Germany (DE)

How to cite

APA:

Okrusch, M., Schuessler, U., Van Den Bogaard, P., Koglin, N., Brätz, H., Lorenz, J.,... Spiegl, T. (2020). Isolated alkaline basalt occurrences in the northern Spessart, Germany: Outposts of the Early Miocene Vogelsberg shield volcano? Neues Jahrbuch für Mineralogie-Abhandlungen, 196(3), 199-219. https://dx.doi.org/10.1127/njma/2020/0194

MLA:

Okrusch, Martin, et al. "Isolated alkaline basalt occurrences in the northern Spessart, Germany: Outposts of the Early Miocene Vogelsberg shield volcano?" Neues Jahrbuch für Mineralogie-Abhandlungen 196.3 (2020): 199-219.

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