caa a22 4500 445839236 CHVBK 20180317145338.0 cr unu---uuuuu 170323e20110501xx s 000 0 eng 10.1007/s00015-010-0048-7 doi (NATIONALLICENCE)springer-10.1007/s00015-010-0048-7 Discovery of Ordovician-Silurian metamorphic monazite in garnet metapelites of the Alpine External Aiguilles Rouges Massif [Elektronische Daten] [Bernhard Schulz, Jürgen von Raumer] The pre-Mesozoic, mainly Variscan metamorphic basement of the Col de Bérard area (Aiguilles Rouges Massif, External domain) consists of paragneisses and micaschists together with various orthogneisses and metabasites. Monazite in metapelites was analysed by the electron microprobe (EMPA-CHIME) age dating method. The monazites in garnet micaschists are dominantly of Variscan age (330-300Ma). Garnet in these rocks displays well developed growth zonations in Fe-Mg-Ca-Mn and crystallized at maximal temperatures of 670°C/7kbar to the west and 600°C/7-8kbar to the east. In consequence the monazite is interpreted to date a slightly pressure-dominated Variscan amphibolite-facies evolution. In mylonitic garnet gneisses, large metamorphic monazite grains of Ordovician-Silurian (~440Ma) age but also small monazite grains of Variscan (~300Ma) age were discovered. Garnets in the mylonitic garnet gneisses display high-temperature homogenized Mg-rich profiles in their cores and crystallized near to ~800°C/6kbar. The Ordovician-Silurian-age monazites can be assigned to a pre-Variscan high-temperature event recorded by the homogenised garnets. These monazite age data confirm Ordovician-Silurian and Devonian-Carboniferous metamorphic cycles which were already reported from other Alpine domains and further regions in the internal Variscides. Swiss Geological Society, 2011 Ordovician nationallicence Variscan nationallicence External Massiv nationallicence Garnet metapelites nationallicence EMP monazite age dating nationallicence P-T path nationallicence Polyphase metamorphism nationallicence Schulz Bernhard TU Bergakademie Freiberg, Institute of Mineralogy, Brennhausgasse 14, 09596, Freiberg, Germany aut von Raumer Jürgen Department of Geosciences, Université de Fribourg, Chemin du Musée 6, 1700, Fribourg, Switzerland aut Swiss Journal of Geosciences SP Birkhäuser Verlag Basel 104/1(2011-05-01), 67-79 1661-8726 104:1<67 2011 104 15 https://doi.org/10.1007/s00015-010-0048-7 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00015-010-0048-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Schulz Bernhard TU Bergakademie Freiberg, Institute of Mineralogy, Brennhausgasse 14, 09596, Freiberg, Germany aut NATIONALLICENCE 700 1- von Raumer Jürgen Department of Geosciences, Université de Fribourg, Chemin du Musée 6, 1700, Fribourg, Switzerland aut NATIONALLICENCE 773 0- Swiss Journal of Geosciences SP Birkhäuser Verlag Basel 104/1(2011-05-01), 67-79 1661-8726 104:1<67 2011 104 15 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer