caa a22 4500 606149775 CHVBK 20210128100535.0 cr unu---uuuuu 210128e20151101xx s 000 0 eng 10.1007/s00531-015-1207-x doi (NATIONALLICENCE)springer-10.1007/s00531-015-1207-x Geochemical composition, petrography and 40Ar/39Ar age of the Heldburg phonolite: implications on magma mixing and mingling [Elektronische Daten] [Michael Abratis, Lothar Viereck, Jörg Pfänder, Roland Hentschel] Differentiated magmatic rocks such as trachyte and phonolite are volumetrically subordinate to mafic volcanic rocks within the Cenozoic Central European Volcanic Province (exceptions are the East Eifel and the Rhön volcanic fields). Within the volcanic field of the "Heldburg dike swarm” (Heldburger Gangschar), the phonolite of the Burgberg near Heldburg represents the only known occurrence of differentiated magmatic rocks. However, the Heldburg phonolite is famous foremost for containing mantle xenoliths (spinel lherzolite). Former studies proposing a cogenetic relationship between the phonolite and the peridotites concluded that the phonolite magma must have evolved under upper mantle conditions. Herewith, we present petrographic and geochemical evidence for magma mixing and mingling in the Heldburg phonolite melt due to the intrusion of mantle-derived basanitic magma, which is exposed today as dikes at the foot of the Heldburg Burgberg. During this process, the mantle xenoliths were introduced into the phonolite melt as they all contain rims of basanitic magma. Extensive mingling features (e.g., schlieren layers, load casts, flame structures, mafic enclaves) are developed, indicating that the basanite and the zoned phonolitic body were melts at the time of mixing. These petrographic and geochemical indications of two coeval melts of different composition are substantiated by 40Ar/39Ar dating, revealing identical ages of ca. 15Ma. Springer-Verlag Berlin Heidelberg, 2015 Central European Volcanic Province nationallicence Heldburg phonolite nationallicence 40Ar/39Ar dating nationallicence Whole rock and mineral geochemistry nationallicence Magma mixing and mingling nationallicence Abratis Michael Institut für Geowissenschaften, Friedrich-Schiller-Universität Jena, Burgweg 11, 07749, Jena, Germany aut Viereck Lothar Institut für Geowissenschaften, Friedrich-Schiller-Universität Jena, Burgweg 11, 07749, Jena, Germany aut Pfänder Jörg Geologisches Institut, Technische Universität - Bergakademie Freiberg, Bernhard-von-Cotta Str. 2, 09599, Freiberg, Germany aut Hentschel Roland Institut für Geowissenschaften, Friedrich-Schiller-Universität Jena, Burgweg 11, 07749, Jena, Germany aut International Journal of Earth Sciences Springer Berlin Heidelberg 104/8(2015-11-01), 2033-2055 1437-3254 104:8<2033 2015 104 531 https://doi.org/10.1007/s00531-015-1207-x text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00531-015-1207-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Abratis Michael Institut für Geowissenschaften, Friedrich-Schiller-Universität Jena, Burgweg 11, 07749, Jena, Germany aut NATIONALLICENCE 700 1- Viereck Lothar Institut für Geowissenschaften, Friedrich-Schiller-Universität Jena, Burgweg 11, 07749, Jena, Germany aut NATIONALLICENCE 700 1- Pfänder Jörg Geologisches Institut, Technische Universität - Bergakademie Freiberg, Bernhard-von-Cotta Str. 2, 09599, Freiberg, Germany aut NATIONALLICENCE 700 1- Hentschel Roland Institut für Geowissenschaften, Friedrich-Schiller-Universität Jena, Burgweg 11, 07749, Jena, Germany aut NATIONALLICENCE 773 0- International Journal of Earth Sciences Springer Berlin Heidelberg 104/8(2015-11-01), 2033-2055 1437-3254 104:8<2033 2015 104 531