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.