Voici les éléments 1 - 10 sur 29
- PublicationMétadonnées seulementContact metamorphism in pelitic rocks on the island of Kos (Greece, Eastern Aegean Sea): a test for the Na-in-cordierite thermometer(1998)
; ;Altherr, RainerLudwig, Thomas
- PublicationMétadonnées seulement
- PublicationMétadonnées seulementMetamorphic evolution of cordierite-bearing migmatites from the Bayerische Wald (Variscan Belt, Germany)(1999)
; ;Berger, AlfonsBlumel, Peter
- PublicationMétadonnées seulementP-T Evolution of a Variscan Lower-Crustal Segment: a Study of Granulites from the Schwarzwald, Germany(2003)
;Marschall, Horst R ;Hanel, Michael
- PublicationMétadonnées seulementComplete solid solution between magnesian schorl and lithian excess-boron olenite in a pegmatite from the Koralpe (eastern Alps, Austria)(2001)
; ;Schreyer, Werner ;Ludwig, Thomas ;Prowatke, Stefan ;Bernhardt, Heinz-JürgenErtl, Andreas
- PublicationMétadonnées seulementSHRIMP dating of zircons from high-grade metasediments of the Schwarzwald/SW-Germany and implications for the evolution of the Moldanubian basement(2004)
;Kober, B ; ;Hanel, MichaelPidgeon, R TFour metasedimentary zircon populations from different tectonometamorphic units of the Central and the Northern Schwarzwald (Variscan belt, SW-Germany) were investigated using SEM, cathodoluminescence and SHRIMP dating. Despite partially strong modifications of primary internal morphologies during Variscan metamorphism at amphibolite (750 degreesC, 0.4-0.6 GPa) and granulite-facies conditions (950-1,000 degreesC, 1.4-1.8 GPa), many grains show well-preserved protolith ages. The detritus indicates a northern Gondwana origin and different Palaeozoic episodes of sediment deposition and consolidation. Two of the studied sediments were deposited in Cam brian/early-Ordovician times and consolidated in positions close to northern Gondwana. Late Ordovician and rare Devonian detritus from sediments of two other tectonometamorphic units indicates much later sedimentation close to the leading edge of Gondwana or a terrane assemblage during northern drift towards Laurussia. Subsolidus growth of new zircon due to Variscan granulite facies metamorphism of one of the tectonometamorphic units is precisely dated at 335 +/- 2 Ma.
- PublicationMétadonnées seulementNd, Sr and Pb isotopic evidence for diverse mantle sources of East African carbonatites(1997)
; ;Hegner, ESatir, Muharrem
- PublicationAccès libreContrasting P-T conditions recorded in ultramafic high-pressure rocks from the Variscan Schwarzwald (F.R.G.)(1995)
; ;Altherr, RainerHanel, MichaelThis paper presents mineralogical and textural data as well as thermobarometric calculations on ultramafic high-pressure rocks from the Variscan basement of the Schwarzwald (F.R.G.). The rocks form small isolated bodies within low-pressure / high-temperature gneisses and migmatites. The results of this study constrain contrasting P-T evolutions for four garnet-bearing ultramafic high-pressure rocks. Two magnesian garnet-spinal peridotites sampled near the southern margin of the Central Schwarzwald Gneiss Complex (CSGC) were equilibrated at 670-740° C and 1.4-1.8rGPa. These P-T conditions are similar to those recorded by eclogites intercalated in the same basement unit. Two garnet websterites sampled from the northern part of the CSGC have comparatively low Mg/(Mg+Fe) and low Cr and Ni abundances and are interpreted as former cumulates. These rocks most probably experienced an initial high-temperature stage within the spinel peridotite stability field, followed by re-equilibration at 740-850° C / 3.2-4.3rGPa and subsequent recrystallization at lower pressures. Further petrologic studies have to reveal whether ultramafic high-pressure rocks of the Schwarzwald can generally be assigned to these two groups which are mainly defined by contrasting peak pressures.
- PublicationAccès libreMetamorphic evolution of garnet-spinel peridotites from the Variscan Schwarzwald (Germany)(1996)
;Altherr, RainerGarnet-spinel peridotites form small, isolated, variably retrogressed bodies within the low-pressure high-temperature gneisses and migmatites of the Variscan basement of the Schwarzwald, southwest Germany. Detailed mineralogical and textural studies as well as geothermobarometric calculations on samples from three occurrences are presented. Two of the garnet-spinel peridotites have equilibrated at 680-770vv°C, 1.4-1.8 GPa within the garnet-spinel peridotite stability field, one of the samples having experienced an earlier stage within the spinel peridotite stability field (790vv°C, <1.8 GPa). The third sample, with only garnet and spinel preserved, probably equilibrated within the garnet peridotite stability field at higher pressures. These findings are in line with the distinction of two groups of ultramafic garnet-bearing high-pressure rocks with different equilibration conditions within the Schwarzwald (670-740vv°C, 1.4-1.8 GPa and 740-850vv°C, 3.2-4.3 GPa) which has previously been established (Kalt et al. 1995). The equilibration conditions of 670-770vv°C and 1.4-1.8 GPa for garnet-spinel peridotites from the Central Schwarzwald Gneiss Complex (CSGC) are similar to those for eclogites of the Schwarzwald and also correspond quite well to those for garnet-spinel peridotites from the Moldanubian zone of the Vosges mountains and of eclogites from the Moldanubian s.str. of the Bohemian Massif.
- PublicationAccès libre
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