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From this period until the uppermost Lower Carboniferous early-variscan metamorphic white micas are present in the sediments.A former extensively distributed crystalline nappe complex located towards the south is favored as the source area for these white micas.Abruptly, without transition late-variscan detrital micas with ages of about 320 Ma appear in Upper Carboniferous sediments. An important exception is the Silurian detrital age of 435 Ma from the Kamm quartzite (cd -) of the Acker- Bruchberg zone.During Lower Carboniferous times the adjoining areas were supplied with early-variscan detritus from southerly regions, whereas the sediments of the Kamm quartzite were derived from the northerly situated Old Red continent.Recent research suggests the provenance could be the Old Red continent.A change of provenances was shown for the sediments in the Rhenohercynian basin in the late Upper Devonian.K1Ar-age determinations on detrital white micas from Cambrian to Upper Carboniferous sediments were carried out, for example, to draw conclusions about the eroded crustal units.The age data indicates potential provenances for the Variscan sediments.
Essential data for the metamorphic evolution in the border area of the Rhenohercynian - Saxothuringian were ascertained by means of K1Ar-age determinations on white micas in fine mineral fractions of very low to low grade metamorphic, pre- to synorogenic sediments.n the Northern Phyllite Zone (here: Wippra Metamorphic Zone), the ages of the metamorphism decrease from SE to NW or 350 to 320 Ma.The exception is the age from the southeasternmost unit of the Wippra Metamorphic Zone at 330 Ma.A Permian post-kinematic thermal event in the Harz Mountains is dated at about 275 Ma. The collision zone of both of these micropiates is represented by the Northern Phyllite Zone, which is the northern margin of the Mid-German Crystalline Rise.geodynamic evolution, geochronology, illite crystallinity, illite polytypes, low grade metamorphism D. The aim of this study was to set timemarks for the tectonometamorphic evolution of both crustal segments during the collisional stage of the Variscan orogeny in Central Europe.