Review of Nd isotopic data and xenocrystic and detrital zircon ages from the pre-Variscan basement in the eastern Bohemian Massif: speculations on palinspastic reconstructions

Hegner, E.; Kröner, Alfred

doi:10.1144/gsl.sp.2000.179.01.09

Cited by 58 publications

(53 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Inherited zircons from protoliths of Ordovician granitoids from Gory Sowie, in the eastern Bohemian Massif, yielded ages of 1.1 -1.3, 1.6-1.8, and 2.2 -2.6 Ga with a scatter of 0.86 -1.56-Ga Nd model ages (Kröner and Hegner, 1998). Hegner and Kröner (2000) report mainly 1.7 -1.4-Ga Nd model ages for the areas of the northeastern Bohemian Massif, and U -Pb ages of detrital zircons or zircon xenocrysts clustering from 600 to 850 Ma, 1.0 to 1.3 Ga, and 1.7 to 2.3 Ga. Following the model of Fernández-Suárez et al (2000), they place most of the source areas in an active margin setting along the Amazonian craton, only few areas showing Grenvillian sources.…”

Section: Provenance Of Detrital Sedimentsmentioning

confidence: 98%

Gondwana-derived microcontinents — the constituents of the Variscan and Alpine collisional orogens

2003

View full text Add to dashboard Cite

The European Variscan and Alpine mountain chains are collisional orogens, and are built up of pre-Variscan ''building blocks'' which, in most cases, originated at the Gondwana margin. Such pre-Variscan elements were part of a preOrdovician archipelago-like continental ribbon in the former eastern prolongation of Avalonia, and their present-day distribution resulted from juxtaposition through Variscan and/or Alpine tectonic evolution. The well-known nomenclatures applied to these mountain chains are the mirror of Variscan resp. Alpine organization. It is the aim of this paper to present a terminology taking into account their pre-Variscan evolution at the Gondwana margin. They may contain relics of volcanic islands with pieces of Cadomian crust, relics of volcanic arc settings, and accretionary wedges, which were separated from Gondwana by initial stages of Rheic ocean opening. After a short-lived Ordovician orogenic event and amalgamation of these elements at the Gondwanan margin, the still continuing Gondwana-directed subduction triggered the formation of Ordovician Al-rich granitoids and the latest Ordovician opening of Palaeo-Tethys. An example from the Alps (External Massifs) illustrates the gradual reworking of Gondwana-derived, pre-Variscan elements during the Variscan and Alpine/ Tertiary orogenic cycles.

show abstract

Section: Provenance Of Detrital Sedimentsmentioning

confidence: 98%

Gondwana-derived microcontinents — the constituents of the Variscan and Alpine collisional orogens

2003

View full text Add to dashboard Cite

show abstract

“…There is no zircon phase which can be clearly attributed to a Mesoproterozoic episode, such as for example the Grenvillian zircons reported from the Bohemian Massif or the Mid-German Crystalline Rise (Gebauer et al 1989;Zeh et al 2001;Linnemann et al 2000;Hegner et al 2000;Friedl et al 2000). This 'Mesoproterozoic gap' is typical for Gondwana sediment sources such as for example the West Africa Craton (WAC; e.g.…”

Section: Discussion Of General Trendsmentioning

confidence: 99%

“…In the Variscan fold belt detritus ages have been successfully used to detect ancient terranes and to reconstruct the geodynamic and geotectonic evolution of Europe during the Palaeozoic (e.g. Franke 2000;Hegner and Kro¨ner 2000;Linnemann et al 2000;So¨llner et al 1997;Tichomirova et al 2001;von Raumer et al 2002von Raumer et al , 2003. The contribution of detrital zircon dating is most important in the understanding of the internal parts of orogens where complex internal nappe structures and high-grade metamorphism often impede the application of palaeomagnetic, stratigraphic and palaeontological methods.…”

Section: Introductionmentioning

confidence: 99%

SHRIMP dating of zircons from high-grade metasediments of the Schwarzwald/SW-Germany and implications for the evolution of the Moldanubian basement

Kober

Kalt

Hanel

et al. 2004

Contributions to Mineralogy and Petrology

View full text Add to dashboard Cite

Four metasedimentary zircon populations from different tectonometamorphic units of the Central and the Northern Schwarzwald (Variscan belt, SWGermany) were investigated using SEM, cathodoluminescence and SHRIMP dating. Despite partially strong modifications of primary internal morphologies during Variscan metamorphism at amphibolite (750°C, 0.4-0.6 GPa) and granulite-facies conditions (950-1,000°C, 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 Cambrian/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.

show abstract

“…The Neoproterozoic protolith ages of 540-580 Ma are typical of granitoids and orthogneisses of the Brunovistulian (van Breemen et al 1982;Scharbert and Batík 1985;Fritz et al 1996;Friedl et al 2000Friedl et al , 2004; see Leichmann and Höck 2008 for review) as well as Saxothuringian and Lugian domains (Hegner and Kröner 2000;Tichomirowa et al 2001;Linnemann et al 2008 and references therein) and they only rarely appear as protolith ages of Moldanubian orthogneisses (Schulmann et al 2005). Importantly, Cambrian ages of 500-520 Ma are absent in the Moravo-Silesian Domain (Brunia), but they are known as the most frequent protolith ages of the Moldanubian orthogneisses, as well as of some ortho gneisses in the Saxothuringian and Lugian domains (Vrána and Kröner 1995;Hegner and Kröner 2000;Tichomirowa et al 2001;Friedl et al 2004;Schulmann et al 2005). Zircons of this age found in the studied samples can be interpreted either as clastic grains coming directly from eroded Cambrian granitoids or volcanics, or they represent recycled crystals from sediments rich in clastic material of Cambrian age.…”

Section: Geochronological Datamentioning

confidence: 99%

“…Zircons of this age found in the studied samples can be interpreted either as clastic grains coming directly from eroded Cambrian granitoids or volcanics, or they represent recycled crystals from sediments rich in clastic material of Cambrian age. Ages older than 650 Ma are known from xenocrystic cores of younger zircons in Brunovistulian, Saxothuringian and Lugian orthogneisses as well as from orthogneisses and granulites of the Moldanubian Domain (Hegner and Kröner 2000;Kröner et al 2000;Tichomirowa et al 2001;Friedl et al 2004 and references therein).…”

Section: Geochronological Datamentioning

confidence: 99%

Metamorphic history of skarns, origin of their protolith and implications for genetic interpretation; an example from three units of the Bohemian Massif

Pertoldová¹,

Týcová²,

Verner³

et al. 2012

Jour. Geosci.

View full text Add to dashboard Cite

Skarns in the Svratka Unit, in the neighbouring part of the Moldanubian Zone and in the Kutná Hora Complex were studied with respect to their metamorphic evolution, major-and trace-element geochemistry, oxygen isotopic composition and zircon ages. Skarns form competent lenses and layers in metamorphosed siliciclastic rocks and preserve some early deformation structures and several equilibrium assemblages representing the products of successive metamorphic reactions. The main rock-forming minerals, garnet and clinopyroxene, are accompanied by less abundant magnetite, amphibole, plagioclase, epidote ± quartz. In the Svratka Unit the early prograde M 1 , prograde/peak M 2 , and retrograde M 3 metamorphic stages have been distinguished. Metamorphic conditions in skarns of the Moldanubian Zone are limited to a relatively narrow interval of amphibolite facies. The prograde and retrograde events in the Kutná Hora Complex skarns probably took place under amphibolite-facies conditions. The presence of magnetite and the increasing proportion of the andradite component in the garnet indicate locally increased oxygen fugacity. Skarn geochemistry does not show systematic differences in the skarn composition among the three units. The regional variations are exceeded by differences among samples from individual localities. The Al 2 O 3 /TiO 2 , Al 2 O 3 /Zr, TiO 2 /Nb ratios point to the variable proportion of the detrital material, combined in skarn protoliths with CaO and FeO, the major non-detrital components. The skarns exhibit elevated abundances of Cu, Zn, Sn and As. The Eu/Eu* ratio varies in the range of 0.5-8.6, the total REE contents vary from 8 to 345 ppm. The lowest ΣREE values (< 100 ppm) occur in skarns with magnetite mineralization. The wide intervals of ΣREE and Eu/Eu* values are interpreted to indicate variations in the temperature and redox conditions among layers of the same locality and at various localities. The oxygen isotope compositions of garnets, pyroxenes and amphiboles from skarns of the Svratka Unit exhibit a range of δ 18 O = 0.1 to 4.1 ‰. In situ (laser-ablation ICP-MS) U-Pb dating of zircon from one of the Svratka Unit skarn bodies yielded a wide range of ages (0.5-2.6 Ga), supporting the detrital origin of this zircon population. The skarn protoliths were probably rocks of mixed detrital-exhalative origin deposited on the sea floor. The geological position of skarns, with their structural and metamorphic record, probably reflect tectono-metamorphic evolution shared with that of their host rocks. The geochemical characteristics, including oxygen isotopic compositions and the presence of detrital zircons with a wide range of ages exclude metasomatic, and point to a sedimentary-exhalative mode of origin for the studied skarns.

show abstract

Review of Nd isotopic data and xenocrystic and detrital zircon ages from the pre-Variscan basement in the eastern Bohemian Massif: speculations on palinspastic reconstructions

Cited by 58 publications

References 58 publications

Gondwana-derived microcontinents — the constituents of the Variscan and Alpine collisional orogens

Gondwana-derived microcontinents — the constituents of the Variscan and Alpine collisional orogens

SHRIMP dating of zircons from high-grade metasediments of the Schwarzwald/SW-Germany and implications for the evolution of the Moldanubian basement

Metamorphic history of skarns, origin of their protolith and implications for genetic interpretation; an example from three units of the Bohemian Massif

Contact Info

Product

Resources

About