Geochronology of the Spessart Crystalline Complex, Mid-German Crystalline Rise

S. Nasir, M. Okrusch, H. Kreuzer, H. Lenzt, A. Höhndorf

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

New Rb-Sr and K-Ar datings help to clarify the geologic history of the Spessart Crystalline Complex, Mid-German Crystalline Rise. The oldest dates, refined by new measurements, are recorded by whole-rock Rb-Sr analyses of the orthogneisses of the Rotgneiss Complex. These confirm a late Ordovician to Silurian age which is interpreted as the time of intrusion of the granitic precursors. Hornblendes, muscovites. and biotites from different lithostratigraphic units and rock types of the Spessart Crystalline Complex yielded K-Ar dates mainly in the range 324 to 318 Ma, an interval which conforms to the analytical precision. Two hornblendes and one muscovite show slightly older dates up to 328 Ma. On the other hand, there is a tail of younger hornblende dates towards 311 Ma, and two hornblendes gave dates as low as 293 and 274 Ma for no immediately obvious reason. The concordant dates around 324 Ma on the three different minerals may be interpreted as marking the time of a rapid uplift and cooling at about the boundary between Early and Late Carboniferous, presumably soon after culmination of the Variscan deformation and amphibolite facies metamorphism.

Original languageEnglish
Pages (from-to)39-55
Number of pages17
JournalMineralogy and Petrology
Volume44
Issue number1-2
DOIs
Publication statusPublished - Mar 1991

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

Fingerprint Dive into the research topics of 'Geochronology of the Spessart Crystalline Complex, Mid-German Crystalline Rise'. Together they form a unique fingerprint.

  • Cite this