: Conclusions and perspectives

The present thesis presents an improved stratigraphic framework, mainly based on additional biostratigraphic data and a newly established sequence stratigraphic scheme. The thesis also worked out faunal assemblages and facies models that can be correlated with adjacent platform areas and that enable to reconstruct environmental changes in interaction with sea-level fluctuations and the paleogeographical development.

Lithostratigraphy and biostratigraphy

Timing of the upper Albian to Turonian platform succession is improved, mainly based on new biostratigraphic data of detailed calcareous nannoplankton investigations and ammonite findings. These results can be integrated into over-regional biozonation-schemes. In particular, the position of the Cenomanian/Turonian boundary can be determined in many cases and the previously termed F/H/S-undifferentiated Formation can be subdivided. The enhanced stratigraphy allows north to south correlations within the entire study area and with successions in Israel and Egypt.

Sequence stratigraphy

A sequence stratigraphic model containing seven sequence boundaries, eight sedimentary sequences, the related systems tracts and maximum flooding surfaces is newly established and correlated over the entire study area.

The recent scheme is compared with a global model and those of Israel, Sinai/Egypt and the Arabian Plate. Differences predominantly result from minor order sea-level changes and regional tectonics. Increased subsidence is mainly observed in the central study area, locally persisting from middle Cenomanian to middle Turonian times. Though, inversion is postulated for the central Wadi Mujib area during upper Cenomanian and lower Turonian times.

Faunal assemblages and paleoecology

Calcareous larger benthic foraminifers abundantly occur in Cenomanian platform deposits. Among other faunal groups (e.g. calcareous algae, rudists) the benthic foraminifers constitute an important source of carbonate. The disappearance of many

species and the general depletion of benthic foraminifer diversity in upper Cenomanian deposits (Shueib Formation) is induced by the coeval sea-level rise and platform flooding that destroyed the shallow water environments. Although, some species persist during this event, and abundantly occur in some parts of the Turonian platform succession, the assemblages are less diverse and larger benthic foraminifers are less important as carbonate producing organisms.

Two ostracode assemblages and five benthic foraminifer assemblages are established. Cenomanian assemblages of both groups are well comparable with those of other Tethyan realm areas, but assemblages of uppermost Cenomanian and lower Turonian deposits exhibit strong differences caused by varying local/regional paleogeographical conditions and by the global sea-level rise during the CT-boundary interval. Assemblages of small opportunistic forms locally replace diverse associations of agglutinated and calcareous foraminifers. Their occurrence reflects restricted deeper subtidal conditions. Based on that small basins are reconstructed on the inner shelf of the central and southern study area during middle Cenomanian times and the Cenomanian/Turonian-boundary interval.

Calcareous nannofossil assemblages exhibit high production rates (high surface water fertility) during a middle Cenomanian interval (central study area) and during the CT-boundary interval (entire area). Both ‘production peaks’ correlate with a deepening and an increase of organic material.

Cyclicities and Accommodation plots

Carbonate cycles of different scale (dm-m scale) are observed in Cenomanian and Turonian limestones and dolostones of the Naur Limestone Formation, the Hummar Formation and the Wadi As Sir Limestone Formation, while peritidal shallowing-up cycles generally prevail. Differences between Cenomanian and Turonian platforms mainly cause in the microfacies changes (e.g. faunal content). Additionally, fossiliferous massive limestones often characterise the shallow part of Cenomanian cycles, while thin (wavy) laminated dolomitic limestones predominate in the upper part of Turonian cycles.

Statistical analyses of lower Cenomanian cyclic successions exhibit differences between high-frequent accommodation patterns of close-by sections, but also correlatable major boundaries and cyclic sets. Therefore, small-scaled correlations are enhanced by comparisons of accommodation plots.

The major accommodation fluctuations are linked to water depth changes, and they indicate the position of higher-ranking sequence boundaries. Therefore, the investigated early Cenomanian accommodation changes are integratable into the present sequence stratigraphic scheme.

The occurrence of peritidal shallowing-up cycles reflects autocyclic mechanisms but co-occurrences of subtidal cycles, the uniform bundling of cycles and correlatable cyclic sets imply a predominant allocyclic control, probably eustasy.

Environmental changes and platform crises

Supratidal to deeper subtidal environments of deposition occur on the platform.

Peritidal to shallow subtidal environments prevail during most times, but their characterising microfacies types differ during the Cenomanian and Turonian. These differences are mostly related to biofacies changes, induced by the late Cenomanian global sea-level rise. That deepening also induced restricted deeper water environments, characterised by low energy and low oxygen conditions, organic carbon-rich deposits, and an opportunistic benthic microfauna. This facies reflects a

‘platform crisis’ and is observed twice within the Jordan succession.

The first crisis is observed in the central study area and coincide with a global middle Cenomanian sea-level rise and local blackshale occurrences in an adjacent shelf area (Israel). The second crisis had an effect on the entire platform and coincides with a global sea-level rise in late Cenomanian to early Turonian times and is most probably equivalent to the global organic anoxic event 2 (CTOAE 2). The facies differences are linked to the paleo-relief that changed in the central area during middle Cenomanian times and during upper Cenomanian to lower Turonian times in the central and southern study area. Based on these results, small basins on the inner shelf are reconstructed for the mentioned areas.

Paleogeography

Based on these integrated stratigraphical and environmental investigations, paleogeographic maps reconstruct the distribution of facies belts and main structural elements on the platform. The early Cenomanian and late Turonian platform shows a uniform distribution of peritidal to shallow subtidal facies belts. A deeper subtidal facies, basinal structures, and increased subsidence occur in the central area during middle Cenomanian times and additional in the south during the late