Neoproterozoic to Cenozoic magmatism in the central part of the Bohemian Massif (Czech Republic): Isotopic tracking of the evolution of the mantle through the Variscan orogeny

0503956 - GLÚ 2020 RIV NL eng J - Journal Article
Dostal, J. - Murphy, J. B. - Shellnutt, J. G. - Ulrych, Jaromír - Fediuk, F.
Neoproterozoic to Cenozoic magmatism in the central part of the Bohemian Massif (Czech Republic): Isotopic tracking of the evolution of the mantle through the Variscan orogeny.
Lithos. 326/327, February 2019 (2019), s. 358-369. ISSN 0024-4937. E-ISSN 1872-6143
Institutional support: RVO:67985831
Keywords : Bohemian Massif * Variscan orogeny * Nd and Sr isotopes * crust * continental lithospheric mantle * rift/extension-related mafic igneous rocks
OECD category: Volcanology
Impact factor: 3.390, year: 2019
Method of publishing: Limited access
https://www.sciencedirect.com/science/article/pii/S0024493718304900?via%3Dihub

The evolution of the mantle source beneath the Teplá-Barrandian block of the Bohemian Massif (Czech Republic) is tracked from the Late Neoproterozoic to the Cenozoic in order to examine the coupling between the crust and underlying continental lithospheric mantle (CLM) during the Late Paleozoic Variscan orogeny. Late Neoproterozoic mafic rocks occur as two types. The oldest type resembles N-MORB, whereas the youngest is characterized by moderate LREE enrichment and within-plate trace element characteristics. Taken together, the geochemistry of the mafic rocks suggests they were emplaced in an intra-oceanic back-arc basin to within-plate setting. Early Paleozoic (Ordovician to Early Devonian) mafic rocks are alkaline, enriched in LREE and Nb relative to HREE and were probably derived from a garnet lherzolite mantle source. Late Paleozoic mafic magmatism occurred during the extensional collapse phase of the Variscan orogen, in the aftermath of the collision between Gondwana and Laurussia. The basalts are within-plate, and transitional between alkaline and tholeiitic compositions but show a relative depletion of Nb. Cenozoic volcanic rocks in the Teplá-Barrandian zone are local representatives of regionally extensive Late Cretaceous to Cenozoic Central European Volcanic Province. The rocks are within-plate, alkaline basalts enriched in LREE and Nb and were derived from garnet lherzolite mantle. These data suggest significant input from upwelling asthenospheric mantle, implying that part of the Permian CLM mantle was re-fertilized by a juvenile post-Variscan CLM.
Permanent Link: http://hdl.handle.net/11104/0295710