Petrogenesis of Cenozoic high-Mg (picritic) volcanic rocks in the České středohoří Mts. (Bohemian Massif, Czech Republic)

0541993 - GLÚ 2022 RIV AT eng J - Článek v odborném periodiku
Krmíček, Lukáš - Ulrych, Jaromír - Jelínek, E. - Skála, Roman - Krmíčková, Simona - Korbelová, Zuzana - Balogh, K.
Petrogenesis of Cenozoic high-Mg (picritic) volcanic rocks in the České středohoří Mts. (Bohemian Massif, Czech Republic).
Mineralogy and Petrology. Roč. 115, č. 2 (2021), s. 193-211. ISSN 0930-0708. E-ISSN 1438-1168
Institucionální podpora: RVO:67985831
Klíčová slova: Ohře/Eger rift * Picrite * Meimechite * Basanite/tephrite * K–Ar ages * Sr–Nd–Pb isotopes
Obor OECD: Geology
Impakt faktor: 2.011, rok: 2021
Způsob publikování: Omezený přístup
https://link.springer.com/article/10.1007/s00710-020-00729-5

Representative samples of high-Mg (picritic) rocks of Eocene to Oligocene age (38 to 21 Ma) from the České středohoří Mts. (CSM) in the Ohře/Eger Rift were studied and compared with Cenozoic high-Mg rocks from the Bohemian Massif. The picritic rocks of the CSM correspond to picrite, meimechite and basanite to tephrite. Individual petrographic types are characterised by the association of mafic minerals: magnesian olivine (Fo_86–80) + clinopyroxene (aluminian diopside) ± amphibole (pargasite/ kaersutite) ± dark mica (ferroan phlogopite). The contents of incompatible elements, such as Nb, Ta, U, Th, the La_N/Yb_N ratios, and the overall Sr–Nd–Pb isotope signatures of the high-Mg rocks partly overlap the basanites of the Ústí Formation, also showing a similar age (44–21 Ma). The Pb isotope signature for all recognised high-Mg rock types is compatible with a variable contribution from an inherited (Variscan) orogenic Pb component preserved in their lithospheric mantle source. Both the high-Mg volcanic rocks from the CSM and from other areas of the Bohemian Massif require the involvement of a heterogenous lithospheric source. Their parental melts were generated by variable degree of melting of an olivine-rich peridotitic mantle, containing clinopyroxene–amphibole (± phlogopite) vein assemblages with highly radiogenic Sr and Pb signatures.
Trvalý link: http://hdl.handle.net/11104/0319498