Non-Marine Permian Biostratigraphy and Biochronology
During the Permian, the single supercontinent Pangaea stretched from pole to pole. Early Permian glacial deposits are found in southern Gondwana. Along the sutures of Pangaea, mountain ranges towered over vast tropical lowlands. Interior areas included dry deserts where dune sands accumulated. Gypsum and halite beds document the evaporation of hot, shallow seas that formed the most extensive salt deposits in the geological record. The Permian period (251 to 299 Ma) encompasses nine ages (stages) arranged into three epochs (series). Most of the Permian marine timescale has been defined by global stratotype sections and points for the stage boundaries. This volume presents new data regarding the biostratigraphy and biochronology of the non-marine Permian and provides a basis for temporally ordering Permian geological and biotic history on land, and correlating that history to events in the marine realm.
The problem of the transition from the Permian to the Triassic Series in southeastern France: comparison with other Peritethyan regions
Published:January 01, 2006
Marc Durand, 2006. "The problem of the transition from the Permian to the Triassic Series in southeastern France: comparison with other Peritethyan regions", Non-Marine Permian Biostratigraphy and Biochronology, Spencer G. Lucas, Giuseppe Cassinis, Joerg W. Schneider
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In the French sedimentary basins, widespread alluvial deposits sealing narrow Permian troughs are referred to as ‘Buntsandstein’. An Early Triassic age is generally put forward despite a lack of any Scythian biochronological elements. In Provence (Southeast Basin) some doubts remain about the age of the latest Permian deposits, and the oldest Triassic fossils (Anisian palynomorphs) appear in the upper ‘Buntsandstein’. Three types of contact occur: disconformity overlain by a quartz-Conglomérate, apparent transition, and angular unconformity, according to an increasing basal incompleteness of the ‘Buntsandstein’. Whereas the Conglomérate was deposited under arid conditions, the overlying fluvial deposits indicate a marked climate change. A transect from France up to the Germanic Basin centre shows that the ‘French Buntsandstein’ cycle might begin considerably before the end of the Permian; the Early Triassic arid ‘event’ is Dienerian/Smithian in age; and the Provençal ‘basal’ Conglomérate corresponds to the uppermost part of a coeval subordinate cycle, and thus the underlying sub-Triassic unconformity represents a hiatus estimated at 10–15 Ma. Works in proGréss confirm that sedimentary climate indicators constitute powerful tools for correlations within non-marine formations devoid of biostratigraphical marker that straddle the Permian–Triassic boundary, at least on the scale of the Western European Plate.