%0 Journal Article
%T Comparison of lithology and tectonometamorphic evolution of units at the northern margin of the Moldanubian Zone: implications for geodynamic evolution in the northeastern part of the Bohemian Massif
%A Pertoldov¨˘ J
%A Verner K
%A Vr¨˘na S
%A Buri¨˘nek D
%J Journal of Geosciences
%D 2011
%I 
%R 10.3190/jgeosci.083
%X Multidisciplinary research evaluates structural, metamorphic and petrochemical data of selected rock types in different units located in the northeastern part of the Bohemian Massif, Czech Republic: (1) the Str¨˘ ek Unit in the northeastern part of the Moldanubian Zone, (2) the Svratka and Kutn¨˘ Hora units correlated with the Orlice-Sn¨§ n¨Şk Unit in Western Sudetes as well as (3) the Poli ka, Hlinsko and Z¨˘b eh units belonging to the Tepl¨˘-Barrandian Zone. Petrochemical data of metasediments of the Poli ka, Hlinsko and Z¨˘b eh units are mutually comparable and confirm a lithological affinity to the upper-crustal Tepl¨˘-Barrandian Zone. The FeO<sub>t</sub>/MnO ratios in metasediments of the Str¨˘ ek Unit and the Svratka Unit indicate differences in the origin of sedimentary protolith rocks.<br>Relict pre-Variscan structures, including extensive migmatization, and high-grade mineral assemblages with peak metamorphic pressures of  1.4 GPa in skarn bodies, are preserved in the Svratka Unit. The evidence for Palaeo-Variscan (390-355 Ma) HP and UHP events, recorded in the high-grade Kutn¨˘ Hora and Orlice-Sn¨§ n¨Şk units, was observed neither in the NE part of the Moldanubian Zone (Str¨˘ ek Unit) nor the Tepl¨˘-Barrandian Zone (Poli ka and Z¨˘b eh units). The Variscan orogenic event imprinted in the Svratka, Poli ka and Z¨˘b eh units was the right-lateral slip along WNW-ESE trending shear zones. This deformation was accompanied by metamorphism at T =  580-650 ˇăC and P =  0.5-0.7 GPa (350-345 Ma) and intrusion of numerous small bodies of syn-deformation calc-alkaline granitoids in the Poli ka and Z¨˘b eh units. The younger metamorphic fabrics in the northeastern part of the Moldanubian Zone reflect a fast exhumation of deep-seated high-grade complexes at  340 Ma. <br>Metamorphic development in felsic granulites of the Str¨˘ ek Unit, metamorphosed c. 340 Ma ago at 850 ˇăC and 1.8 GPa, was followed by decompression to T   790 ˇăC and P = 1.3 GPa and finally T   700 ˇăC and P =  0.4 GPa. In contrast, B¨§stvina granulite in the Kutn¨˘ Hora Unit, with the  360 Ma high-grade metamorphism at 800-920 ˇăC and 1.8-2.1 GPa, is free of such a HT-LP overprint. Thus the data indicate that the Svratka and Kutn¨˘ Hora units, exhibiting numerous mutual differences, should not be considered as belonging to the Moldanubian Zone as they evolved as independent entities. <br>The geochemical data on garnet-clinopyroxene skarns from the Moldanubian Zone, the Svratka and Kutn¨˘ Hora units do not provide mutually distinguishing features. This is largely due to a very wide compositional variation in rocks in
%U http://www.jgeosci.org/content/jgeosci.083_2010_4_pertoldova.pdf