Lower Cretaceous north African carbonate platforms (Tunisia/Egypt) and global climate change

Matthias Heldt, Martina Bachmann, Rüdiger Stein (AWI), Jens Lehmann

DFG Projekt Nummer BA 1571/1-1

Long-term and short-term effects of the Early Cretaceous global change on shallow-marine carbonate platform sedimentation are being studied. Intensive volcanic activity during the later Early Cretaceous contributed to high atmospheric CO2 contents, which are related to global sea-level variations, climate changes as well as to Oceanic Anoxic Events OEA 1a and OEA 1b (e.g. Jenkyns & Wilson, 1999; Larson & Erba, 1999; Price, 1999). The influence of these important parameters on the local sedimentation patterns of carbonate platforms and their ecologic parameters are being analysed.
Sediments of the Barrêmian to Albian of two platforms are being compared. The two selected platforms (Levant Platform, Sinai and Central Tunisian Platform) are connected to the large North African or Arabian platform systems and thus cover large areas of the southern Tethyan shelf.
The following parameters will be recorded: biochronostratigraphy, sedimentation patterns and facies variations of 2nd- and 3rd-order cycles (sequence stratigraphic and cyclostratigraphic interpretation), palecologic and climate changes, stable isotopes, geochemical studies of Corg-rich sediments. Basis data are available for the Levant Platform, which allow a detailed study of the relevant intervals. The investigation of Tunisian succession of the same age will allow a trans-regional interpretation of the results.