DEVELOPMENT OF THE PALAEOGEOGRAPHY OF PANGAEA FROM LATE CARBONIFEROUS TO EARLY PERMIAN

Abstract

Old and new, well and poorly known lithofacies data of Moscovian and Artinskian age in the area limited by the Arctic Sea and central Africa, the Atlantic Ocean and the Ural Mountains have been plotted on present-day maps. The facies-mapped and related environments allow the recognition of a series of different palaeogeographic/palaeotectonic units including the Late Carboniferous to Early Permian deep sea to Palaeo-Tethyan ocean, west Siberia–Kazakhstan continent and Uralian–Kazakhstan–Tienshan arc, Uralian foredeep up to the closing arms of the Uralian ocean, Precaspian basin, Russian platform, Donets rift basin, Caucasian–Moesian–Dobrogean–Polish–Oslo basinal belt, syn-tectonic Hercynian foreland basin, intramontane post-Hercynian basins, Iran–Anatolian–Hellenic–Dinaric–Carnic basin branching into the Hungarian seaway, Apennine basin branching into the Cantabrian and South Portuguese basins, Oman–Iraq–Levantine–Sicily deep basin and inferred oceanic sea-way, south Peri-Tethyan platform basins, east Arabian cratonic basin, and north African intracratonic basins. The subsidence/sedimentation trends of these units were correlated and compared through lithostratigraphic logs, bathymetric curves and uncorrected cumulative stratigraphic curves. The sets of original and processed data were used to test two different palaeodynamic models, a Pangaea A model, static from Late Carboniferous to Triassic, and a mobile Pangaea B model with different dextral displacements between Laurussia and Gondwanaland in the same time interval. The best fit for our data requires a strike-slip offset of about 800 km from Moscovian to Artinskian time. This model implies a first quasi-Pangaea or Pangaea B assembly at the Carboniferous/Permian transition, an ephemeral Pangaea B break-up driven by an Early Permian oblique rift across the Mediterranean to Caribbean areas, and a final Pangaea A assembly in the Mid-to-Late Permian. The two palinspastic maps describing the model have been cross-checked by comparison with an independent set of biogeographic features of Late Carboniferous and Early Permian. Overall floral, reptile, and marine benthic organism distribution is consistent with the Early Permian trans-Pangaea seaway inferred from facies and palaeodynamic analyses.