Abstrakt
We have analyzed 35 new samples of well-characterized mantle xenoliths hosted by Cenozoic lavas from several different localities in the BM: the České Středohoří Volcanic complex (CSVC) located in the central part of the Ohře/Eger rift, NE Bavaria representing the western continuation of the rift system, volcanoes in the NE continuation of the rift system (Lusatia, Lower Silesia) and an isolated volcano in E Bohemia representing the off-rift settings. We aimed at using Os isotopes in mantle xenoliths to assess differences between individual mantle domains of major tectonic units of the BM and link them with their potential source mantle signatures.When previously published Re-Os data for Kozákov xenoliths (NE Bohemia, [6]) are included, suite of 49 samples can be examined for their Rhenium-depletion ages (TRD).
Among them, 25 samples exhibit TRD <0.5 Ga, 15 samples lie in the range of ~0.5-1 Ga and TRD ages in nine samples yield vary from 1.0 to 2.0 Ga. The ages show high scatter even in the individual localities suggesting rather heterogeneous lithospheric mantle beneath the BM with likely no clear connection to different tectonic units.