Architecture of carbonate platforms in Egypt

Christian Scheibner

DFG-Graduierten Kolleg Stoff-Flüsse in marinen Geosystemen

Simulation of Paleocene deposition on the Galala-Wadi Araba high (Egypt).

Platform-to-basin transitions are key areas for understanding processes that involve both the platform and the adjacent basin. Only here the progradation or retrogradation of the platform can be dated precisely with calcareous nannofossils or planktic foraminifers that live in deep waters and shallow benthic organisms from the platform. This temporal accuracy is necessary to discuss and correlate climatic and environmental processes on the platform with those in the adjacent basin. Furthermore, platform-to-basin settings provide essential information on the type of platform. Until now, the reasons for changes between different platform morphologies are only poorly understood. Possible reasons for morphologic transitions are the lack of framebuilding organisms, large extinctions of the dominating organisms, oceanic (upwelling and eutrophication), climatic, and tectonic factors (Burchette and Wright, 1992). With respect to these fundamental geological aspects the Upper Cretaceous to Lower Paleogene successions of the Galala Mountains in the Eastern Desert of Egyt are of special interest.

Simulation run (with PHIL)

Paleocene stage

In this simulation the chosen parameter is the lithology. The first part is characterised by small fluctuations of sea level, low subsidence rates and low carbonate input resulting into very low sedimentation. The second part starting from 59,25 Ma is characterised by high sea-level fluctuations, resulting in alternating sedimentation and erosion.


Maastrichian stage

In this simulation the chosen parameter is the paleobathymetry. In the first part of the simulation aggradation dominates, due to high subsidence and sea-level rise. In the second part the sea-level falls and the sequences are prograding (66,9 Ma). The third part of the simulation is again characterised by rising sea level, resulting first in an aggradation followed by retrogradation after a more rapid sea-level rise (66.0 Ma). The last part is characterised by progradation due to a stable sea level and low subsidence-rates (65.5 Ma).