Publisher © Czech Geological Survey, ISSN: 2336-5757 (online), 0514-8057 (print)

Some results of comparative research of durbachitic plutonic rocks from the Bohemian Massif, the Vosges and the Black Forest (Schwarzwald)

 

František Holub

Geoscience Research Reports 38, 2005 (GRR for 2004), pages 101–102

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Abstract

Durbachitic rocks are ultrapotassic plutonic rocks corresponding to amphibole-biotite melasyenite (durbachite), quartz melasyenite and melagranite (the Čertovo břemeno type in the Bohemian Massif and Granite des Cretes in the Vosges). This rock group is highly typical for some parts of the Hercynian orogenic belt of central to western Europe and is associated with exhumed lower-crustal metamorphic rocks of the former orogenic root. Our research comprising a new set of whole-rock analyses including more than 40 trace elements has demonstrated that durbachitic rocks from the Moldanubian part of the Bohemian Massif are petrographically and geochemically identical to those from the Vosges and from the classical locality at Durbach in the Black Forest (Schwarzwald). Therefore, any plausible petrogenetic model should be appropriate for all these rocks regardless the area of their occurrences. The data are compatible with the hypothesis that the „durbachite series" can be derived from mafic ultrapotassic magma of mantle origin due to intense mixing (hybridization) with granite melts derived from the continental crustal rocks.