Nachweis altpaläozoischer Primäralter (Rb-Sr) und karbonischer Abkühlungsalter (K-Ar) der Muskovit-Biotit-Gneise des Spessarts und der Biotit-Gneise des Böllsteiner Odenwaldes

Transformation of a magmatic arc and an orogenic root during oblique collision and it’s consequences for the evolution of the European Variscides (Mid-German Crystalline Rise)

“…PT-conditions are typically Barrovian with upper greenschist to upper amphibolite conditions at 4-8 kb (see Okrusch 1995 for compilation;Willner et al 1991, Franz & Seifert 1997. All geochronologic data measured on hornblende, muscovite, and biotite fall within the same range at 318-324 Ma in the eastern Odenwald, Spessart, and Rho¨n indicating very rapid cooling following peak metamorphism (Nasir et al 1991, Lippolt 1986, Schmidt et al 1986). These ages are identical to peak metamorphic ages dated for the northern Phyllite zone in the juxtaposed southern Rhenish Massif (Klu¨gel 1995).…”

“…The uppermost tectonic unit (Alzenau-Elterhof) consists of a variegated series of amphibolites (partly MORB-type), marbles, calcschists, and metapelites. All metasedimentary piles are intruded prior to their metamorphism by Silurian-Lower Devonian metagranitoids with shallow intrusion depths and with subduction-related affinities (Lippolt 1986, Okrusch and Richter 1986, Henneberg et al 1994, Dombrowski et al 1995. With exception of a diorite in the southern Spessart, no Variscan synorogenic magmatic features like those observed further west have been identified.…”

“…Relics of an earlier NW-directed stacking stage are only reported from the Spessart. This entire period lasted from 360-325 Ma (Kreuzer and Harre 1975, Montigny et al 1983, Lippolt 1986, Schmidt et al 1986, Hess and Schmidt 1989, Nasir et al 1991, Zeh 1995. It is largely finished at the onset of subduction of continental material from the lower plate as reflected from undeformed lamprophyric dykes and granites which intrude the final brittle strike slip fault system.…”

Provenance of Pleistocene Rhine River Middle Terrace sands between the Swiss–German border and Cologne based on U–Pb detrital zircon ages

“…Another option is a derivation from the mid-German crystalline rise. In the Spessart and neighboring areas, Silurian ages such as c. 414 and 439 Ma (Lippolt 1986;Nasir et al 1991) and c. 418 and 410 Ma (Dombrowsky et al 1995) were recorded (Sommermann 1993;Reischmann and Anthes 1996;Siebel et al 1997). Alternatively, this age peak could be connected to the main parts of the Caledonian orogen now underlying northern Germany and being exposed in the British Isles and Scandinavia (McKerrow et al 2000;Krawczyk et al 2008).…”

The role of the Kupferschiefer in the formation of hydrothermal base metal mineralization in the Spessart ore district, Germany: insight from detailed sulfur isotope studies

“…At the end of the metamorphic cycle, the metamorphic rocks were intruded by an igneous complex composed of quartz diorite, granodiorite, and minor granite. Consistent K-Ar and Ar-Ar dates of minerals from various rock types indicate that uplift and cooling of the SCC took place at 325-315 Ma (Lippolt 1986;Nasir et al 1991;Dombrowski et al 1994). During the Permian, several rhyolite bodies were emplaced in the Spessart for which no geochronological data are yet available.…”