Horst Peter Hann

Kinematic evolution of the Romanian Carpathians

Abstract The regional pattern of contraction and extension directions and the evolution of the strain field from Paleogene to Neogene times enabled a reconstruction of the migration path of the Carpathian collision front. The Carpathian nappes were thrust around the Moesian Plate during Paleogene and Early Neogene times and protruded into a small oceanic embayment between the Moesian and European plates. The arc structure of the Carpathian fold-thrust belt was formed in Late Neogene times as a result of the eastward-escaping Tisza–Dacia block, due to N-directed convergence of the Adriatic plate and the retreating subduction of an oceanic slab. Brittle deformation structures in the Romanian Carpathians suggest three tectonic events related to major plate motions: (1) Paleogene to Middle Miocene NE to ENE contraction caused right-lateral curved strike-slip faults; (2) Middle Miocene to Pliocene fan-shaped orientations of contraction directions were caused by right-lateral oblique convergence in the Southern Carpathians, frontal convergence in the southern Eastern Carpathians and left-lateral convergence in the northern Eastern Carpathians; (3) Pleistocene to Holocene general E–W extension and N–S contraction in the Carpathian arc and local ESE–WNW contraction in the Vrancea area is related to the late roll back stage and break-off of the subducted slab in the bend area.

Late Cambrian–Ordovician northeastern Gondwanan terranes in the basement of the Apuseni Mountains, Romania

Abstract: The pre-Alpine basement of the Apuseni Mountains (Romanian Carpathians) comprises three terranes: Someş, Baia de Arieş and Biharia. Metaigneous rocks within these terranes record Late Cambrian–Ordovician U–Pb zircon crystallization ages. Two samples from an orthogneiss layer in the Someş terrane yielded an age of 459.8 ± 2.7 Ma. In the Baia de Arieş terrane, an augen gneiss yielded an age of 470.8 ± 3.8 Ma, a porphyroid yielded an age of 467.8 ± 3.8 Ma and two metagranites yielded ages of 467.8 ± 4.7 Ma and 467.1 ± 3.9 Ma, respectively. Three samples from a metagranitoid outcrop located in the lower part of the Biharia terrane yielded an age of 495.0 ± 2.1 Ma. Three other samples from a metabasite layer situated lithostratigraphically several hundred metres above the metagranitoid yielded an age of 477.8 ± 3.2 Ma. Detrital U/Pb zircon ages from a paragneiss interlayered within the Baia de Arieş terrane scatter between 548 and 3518 Ma. Detrital zircon ages together with the inherited ages recorded by magmatic zircon populations suggest a northeastern Gondwanan provenance for the Someş, Baia de Arieş and Biharia terranes, adjacent to the Arabian–Nubian Shield. Lead loss in some zircons is interpreted to have taken place during the Variscan orogeny. Supplementary material: Coordinates for samples from the Apuseni Mountains, Palaeozoic palaeogeographical models of Gondwana, Laurentia and Baltica to the formation of Pangaea, sample preparation and analytical procedures, sample description, and age measurements of zircon grains are available at http://www.geolsoc.org.uk/SUP18425.

Zircon and Garnet Geochronology of Eclogites from the Moldanubian Zone of the Black Forest, Germany

The Moldanubian zone of the Black Forest, Germany, part of the internal zone of the central European Variscan belt, exposes high‐pressure metamorphic rocks as small eclogite lenses in host gneisses. We report zircon U‐Pb and Pb‐Pb ages and garnet Sm‐Nd and Pb‐Pb ages for five eclogites. The less mobile trace element contents of these eclogites are similar to those of mid‐ocean ridge basalts but have moderate to highly fractionated concentrations of the rare earth elements, enrichments in the incompatible elements, and negative anomalies in the high‐field strength elements. Initial εNd values range from \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape

Testing tectonic models with geochemical provenance parameters in greywacke

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Ordovician and Silurian protolith ages of metamorphosed clastic sedimentary rocks from the southern Schwarzwald, SW Germany: a palynological study and its bearing on the Early Palaeozoic geotectonic evolution

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Alpine polyphase tectono-metamorphic evolution of the South Carpathians: A new overview

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