caa a22 4500 475827740 CHVBK 20180406123833.0 cr unu---uuuuu 170329e20000301xx s 000 0 eng 10.1007/s005310050306 doi (NATIONALLICENCE)springer-10.1007/s005310050306 Zircon ages and Nd isotopic and chemical compositions of orthogneisses from the Black Forest, Germany: evidence for a Cambrian magmatic arc [Elektronische Daten] [F. Chen, E. Hegner, W. Todt]  Single zircon U-Pb dating combined with 207Pb/206Pb ages obtained by the evaporation method constrains the emplacement of tonalitic, trondhjemitic, and granodioritic orthogneisses of the Moldanubian zone in the Black Forest between 500 and 510 Ma. Two detrital zircon populations of 1.9 and 1.6 Ga indicate Early-Middle Proterozoic material in the former setting of the basement. The initial eNd values range from -0.1 to -3.4 and mean crustal residence ages of 1.0-1.4 Ga are consistent with involvement of Early-Middle Proterozoic crust, and a subordinate juvenile component probably originating from subduction-related melting of the mantle. The orthogneisses have fractionated REE patterns and slightly higher K2O/Na2O ratios than typical low-K tonalite-trondhjemite-granite suites. The chemical data are interpreted as evidence for melting of amphibolite and contributions from evolved crust. The emplacement of the orthogneisses was superceded by a high-temperature metamorphic event at ∼480 Ma which we interpret as a result of lithospheric thinning in a marginal basin behind a Cambrian magmatic arc. Springer-Verlag Berlin Heidelberg, 2000 Key words Variscan belt nationallicence Moldanubian zone nationallicence Black Forest nationallicence Orthogneiss nationallicence Zircon dating nationallicence ¶Nd isotopes nationallicence Geochemistry nationallicence Chen F. Institut für Mineralogie, Petrologie und Geochemie, Universität Tübingen, Wilhelmstrasse 56, D-72074 Tübingen, Germany e-mail: fukun.chen@uni-tuebingen.de Fax: +49-7071-295713, DE aut Hegner E. Institut für Mineralogie, Petrologie und Geochemie, Universität Tübingen, Wilhelmstrasse 56, D-72074 Tübingen, Germany e-mail: fukun.chen@uni-tuebingen.de Fax: +49-7071-295713, DE aut Todt W. Max-Planck-Institut für Chemie, Postfach 3060, D-55020 Mainz, Germany, DE aut https://doi.org/10.1007/s005310050306 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s005310050306 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Chen F. Institut für Mineralogie, Petrologie und Geochemie, Universität Tübingen, Wilhelmstrasse 56, D-72074 Tübingen, Germany e-mail: fukun.chen@uni-tuebingen.de Fax: +49-7071-295713, DE aut NATIONALLICENCE 700 1- Hegner E. Institut für Mineralogie, Petrologie und Geochemie, Universität Tübingen, Wilhelmstrasse 56, D-72074 Tübingen, Germany e-mail: fukun.chen@uni-tuebingen.de Fax: +49-7071-295713, DE aut NATIONALLICENCE 700 1- Todt W. Max-Planck-Institut für Chemie, Postfach 3060, D-55020 Mainz, Germany, DE aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer