ORIGINAL PAPER

International Journal of Earth Sciences

, Volume 88, Issue 1, pp 49-59

Determining sedimentation ages of high-grade metamorphic gneisses by their palynological record: a case study in the northern Schwarzwald (Variscan Belt, Germany)

  • M. HanelAffiliated withMineralogisches Institut, Im Neuenheimer Feld 236, D-69120 Heidelberg, Germany Fax: +49 6221 544805 e-mail: mhanel@classic.min.uni-heidelberg.de
  • , M. MontenariAffiliated withGeologisches Institut, Albertstrasse 23b, D-79104 Freiburg, Germany
  • , A. KaltAffiliated withMineralogisches Institut, Im Neuenheimer Feld 236, D-69120 Heidelberg, Germany Fax: +49 6221 544805 e-mail: mhanel@classic.min.uni-heidelberg.de

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

 In the northern Schwarzwald (Moldanubian Zone of the Variscan belt), paragneisses drilled from approximately 2500 m depth at the Bühl-1 drilling site have experienced amphibolite-facies metamorphism and were later partly transformed to mylonites under greenschist-facies conditions. Completely graphitised acritarchs and chitinozoans were recovered from these paragneisses and mylonitic gneisses. Whereas both groups of palynomorphs give evidence of a marine depositional environment, only the chitinozoans are stratigraphically useful in this case and indicate a Paleozoic age. Previous findings of acritarchs in a different high-grade metamorphic gneiss unit within the Schwarzwald indicate an Upper Proterozoic marine sedimentation age. The spectrum of palynomorphs found thus far in the Schwarzwald in combination with petrological data suggests that within the Moldanubian domain of the Armorican microplate, rocks with different sedimentary records later experienced diverging prograde metamorphic histories. In general, the results reveal that palynological studies in combination with petrological data are a promising tool for reconstructing pre-orogenic settings in collisional belts.

Key words Palynology Sedimentation age Amphibolite-facies gneisses Schwarzwald Variscan belt