0000000000602885
AUTHOR
Gerald Anthes
Timing of granitoid magmatism in the eastern mid-German crystalline rise
Abstract The eastern parts of the mid-German crystalline rise (MGCR) are exposed in the Spessart, Ruhla and Kyffhauser crystalline complexes and known from boreholes in the region of Dessau. In this study we determined igneous formation ages of granitoid intrusives and orthogneisses from this part of the MGCR using the Pb/Pb single zircon dating technique. The intrusion ages of the granitoids range from ∼489 to ∼302 Ma (i.e. from lower Ordovician to upper Carboniferous). The grouping of these ages marks several distinct magmatic episodes during the Variscan orogeny, with a major peak at the end of the lower Carboniferous. We tentatively suggest the following geodynamic scenario for the orig…
Geochronology of the mid-German crystalline rise west of the River Rhine
The mid-German crystalline rise has its westernmost exposures at the western margin of the Rhine graben in the southern Pfalz and the northern Alsace. The outcrops are made up of granitoid rocks and minor volcano-sedimentary sequences. Radiometric ages obtained by U/Pb, Pb/Pb, Sm/Nd and Rb/Sr analyses of the igneous rocks from this area range from ∼433 to ∼325 Ma thus covering a time span from the Silurian to the end of the lower Carboniferous. Because the investigated rocks are — according to their chemical composition — largely related to subduction zone environments, the following three geodynamical scenarios are postulated, always taking subduction of oceanic crust beneath the mid-Germa…