Author(s): Štědrá V | Nahodilová R
Journal: Journal of Geosciences
ISSN 1802-6222
Volume: 54;
Issue: 2;
Start page: 135;
Date: 2009;
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ABSTRACT
Eclogites from the inner part of the KHC (Roztěž, Bořetice) mostly had a Mg-rich tholeiitic protolith. Chemical, mineralogical and metamorphic data reveal that these eclogites are petrologically similar to the eclogite samples from the better known Běstvina Unit. Eclogites from Bořetice, Poličany and Roztěž preserve relict mineral assemblage from a pre-eclogite stage, enclosed in garnet with prograde zoning pattern. They bear mineralogical evidence of a very high-pressure history, even substantially higher (maximum 8.4 wt. % of Na2O in Cpx, P˜ 4.3 GPa) than the previously described eclogites from Spačice and Úhrov in the Běstvina Unit.A set of three eclogites from the northern margin of the Moldanubian Zone south of Chotěboř was used for comparison (Bída, Borovský Creek, Krátká Ves). They preserve also a peak pressure record that corresponds to minimum pressures above 2.0 GPa.Better understanding of regional relationships amongst the discussed units can be achieved only using isotopic and geochronological data. ]]>
Journal: Journal of Geosciences
ISSN 1802-6222
Volume: 54;
Issue: 2;
Start page: 135;
Date: 2009;
VIEW PDF
DOWNLOAD PDF Original pageABSTRACT
Eclogites from the inner part of the KHC (Roztěž, Bořetice) mostly had a Mg-rich tholeiitic protolith. Chemical, mineralogical and metamorphic data reveal that these eclogites are petrologically similar to the eclogite samples from the better known Běstvina Unit. Eclogites from Bořetice, Poličany and Roztěž preserve relict mineral assemblage from a pre-eclogite stage, enclosed in garnet with prograde zoning pattern. They bear mineralogical evidence of a very high-pressure history, even substantially higher (maximum 8.4 wt. % of Na2O in Cpx, P˜ 4.3 GPa) than the previously described eclogites from Spačice and Úhrov in the Běstvina Unit.A set of three eclogites from the northern margin of the Moldanubian Zone south of Chotěboř was used for comparison (Bída, Borovský Creek, Krátká Ves). They preserve also a peak pressure record that corresponds to minimum pressures above 2.0 GPa.Better understanding of regional relationships amongst the discussed units can be achieved only using isotopic and geochronological data. ]]>
