RT Journal Article
T1 The Permian–Triassic transition and the onset of Mesozoic sedimentation at thenorthwestern peri-Tethyan domain scale: Palaeogeographic maps andgeodynamic implications
A1 Bourquin, Sylvie
A1 Bercovici, Antoine
A1 López Gómez, José
A1 Diez Ferrer, José B.
A1 Broutin, Jean
A1 Ronchi, Ausonio
A1 Durand, Marc
A1 Arche, Alfredo
A1 Linol, Bastien
A1 Amour, Frédéric
AB The main aim of this paper is to review Middle Permian through Middle Triassic continental successions inEuropean. Secondly, areas of Middle–Late Permian sedimentation, the Permian–Triassic Boundary (PTB) andthe onset of Triassic sedimentation at the scale of the westernmost peri-Tethyan domain are defined in orderto construct palaeogeographic maps of the area and to discuss the impact of tectonics, climate and sedimentsupply on the preservation of continental sediment.At the scale of the western European peri-Tethyan basins, the Upper Permian is characterised by a generalprogradational pattern from playa-lake or floodplain to fluvial environments. In the northern Variscan Beltdomain, areas of sedimentation were either isolated or connected to the large basin, which was occupied bythe Zechstein Sea. In the southern Variscan Belt, during the Late Permian, either isolated endoreic basinsoccurred, with palaeocurrent directions indicating local sources, or basins underwent erosion and/or therewas no deposition. These basins were not connected with the Tethys Ocean, which could be explained by ahigh border formed by Corsica–Sardinia palaeorelief and even parts of the Kabilia microplate. The palaeofloraand sedimentary environments suggest warm and semi-arid climatic conditions.At the scale of the whole study area, an unconformity (more or less angular) is observed almost everywherebetween deposits of the Upper Permian and Triassic, except in the central part of the Germanic Basin. Thesedimentation gap is more developed in the southern area where, in some basins,Upper Permian sediment does notoccur. The large sedimentary supply, erosion and/or lack of deposition during the Late Permian, as well as thevariable palaeocurrent direction pattern between theMiddle–Late Permian and the Early Triassic indicate a period ofrelief rejuvenation during the Late Permian. During the Induan, all the intra-belt basins were under erosion andsediment was only preserved in the extra-belt domains (the northern and extreme southern domains). In thenorthern domain (the central part of the Germanic Basin), sediment was preserved under the same climaticconditions as during the latest Permian, whereas in the extreme southern domain, it was probably preserved in theTethys Ocean, implying a large amount of detrital components entering themarinewaters. Mesozoic sedimentationbegan in the early Olenekian; the ephemeral fluvial systems indicate arid climatic conditions during this period.Three distinct areas of sedimentation occur: a northern and southern domain, separated by an intra-belt domain.The latter accumulated sediments during the Early–Middle Permian and experienced erosion and/or no-depositionconditions between the Middle–Late Permian and the beginning of Mesozoic sedimentation, dated as Anisian toHettangian. At the top of the Lower Triassic, another tectonically induced, more or less angular unconformity isobserved: the Hardegsen unconformity, which is dated as intra-Spathian and is especially found in the NorthEuropean basins. This tectonic activity created new source areas and a new fluvial style, with marine influences atthe distal part of the systems. During the Anisian and Ladinian, continental sedimentation was characterised by a retrogradational trend. In other words, the fluvial system evolved into fluvio-marine environments, attesting to adirect influence of the Tethys Ocean in the southern and northern domains. Both at the end of the Olenekian(Spathian) and during the Anisian, the presence of palaeosols, micro- andmacrofloras indicate less arid conditionsthroughout this domain
PB Elsevier
SN 0031-0182
YR 2011
FD 2011
LK https://hdl.handle.net/20.500.14352/42469
UL https://hdl.handle.net/20.500.14352/42469
LA eng
DS Docta Complutense
RD 30 abr 2024