The continuum between Cadomian orogenesis and opening of the Rheic Ocean: Constraints from LA-ICP-MS U-Pb zircon dating and analysis of plate-tectonic setting (Saxo-Thuringian zone, northeastern Bohemian Massif, Germany)

Abstract

This paper is dedicated to Jean-Jacques Chauvel (1935-2004) ABSTRACT Sediment provenances and magmatic events of Late Neoproterozoic (Ediacaran) and Cambro-Ordovician rock complexes from the Saxo-Thuringian zone are constrained by new laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U-Pb dating of detrital zircons from fi ve sandstones and magmatic zircons from an ignimbrite and one tuffi te. These geochronological results in combination with the analysis of the plate-tectonic setting constrained from fi eld observations, sedimentological and geochemical data, and trends of the basin development are used to reconstruct Cadomian orogenic processes during the Late Neoproterozoic and the earliest Cambrian. A continuum between Cadomian orogenesis and the opening of the Rheic Ocean in the Cambro-Ordovician is supported by the data set.

Provenance of Pleistocene Rhine River Middle Terrace sands between the Swiss–German border and Cologne based on U–Pb detrital zircon ages

“…At the end of the Neoproterozoic and during the Early Cambrian, periGondwanan terranes drifted toward the north, either as separate entities or as parts of Africa (Robardet 2003;Tait et al 1997;Linnemann et al 2004Linnemann et al , 2007 and were reassembled during the Caledonian and Variscan orogenies (e.g., Kroner et al 2007;Krawczyk et al 2008;Nance et al 2010;Zeh and Gerdes 2010). In the Early Middle Jurassic, major rifting phases led to the formation of continental rift zones and the opening of the Alpine Tethys and the North Sea (Ziegler and Dèzes 2006;Robertson 2007).…”

“…7, 8). Cadomian ages are absent on Baltica and Laurentia (e.g., Nance and Murphy 1994;Zeh et al 2001;Linnemann et al 2007).…”

“…Detrital zircon ages have been successful in discriminating between different source regions and sediment delivery pathways (e.g., Sircombe 1999; Augustsson et al 2006;Bahlburg et al 2010). The presence of a given zircon age population and similarities in age distributions is taken as evidence of a common provenance (e.g., Cawood et al 2003Cawood et al , 2007Bahlburg et al 2010;Linnemann et al 2007).…”

Death of super-continents and birth of oceans heralded by discrete A-type granite igneous events: the case of the Variscan-Alpine Europe

“…In the external domain, the Vesser MOR-related complex comprises a basalt (508 ± 2 Ma) -dacite (497 ± 2 Ma) -rhyolite volcanic suite, associated with a 502 ± 2 Ma tholeiitic gabbro-dolerite. The nearby Ediacaran sedimentary assemblages were intruded by a c. 490 Ma (Furongian) granite (Linnemann et al 2007). In the internal domain, they are cut by 490 ± 3 Ma (Furongian) to 485 ± 6 Ma (Tremadocian) granites and covered unconformably by two episodes of 487 ± 5 Ma (Cambrian-Ordovician boundary) rhyolitic pyroclastic units and 479 ± 5 Ma (Tremadocian-Floian) porphyroid (Linnemann et al 2007).…”

“…The nearby Ediacaran sedimentary assemblages were intruded by a c. 490 Ma (Furongian) granite (Linnemann et al 2007). In the internal domain, they are cut by 490 ± 3 Ma (Furongian) to 485 ± 6 Ma (Tremadocian) granites and covered unconformably by two episodes of 487 ± 5 Ma (Cambrian-Ordovician boundary) rhyolitic pyroclastic units and 479 ± 5 Ma (Tremadocian-Floian) porphyroid (Linnemann et al 2007). During the Carboniferous, contrasting igneous suites emplaced under shear stress regimes that changed abruptly from the 340-330 Ma (Visean) high-K Meissen granite association, related to dextral strike-slip movement of the Elbe Fault Zone, to the 327 ± 4 Ma (Visean-Serpukhovian boundary) Markersbach A-type granite, showing no strike-slip influence (Hofmann et al 2008).…”