الفهرس 
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Abstract
Systematic paleontology
One hundred and seventy two species were identified including seventy one bivalves, forty-three gastropods, twenty-six ammonites and thirty-two echinoids.
Phylum Classs order Family Genera Species
Mollusca Cephalopoda 1 9 12 26
Bivavalveia 6 17 28 71
Gastropoda 5 14 24 43
Echinodermata Echinoidea 5 6 12 32
A new oyster species Exogyra ribosa is identified here; also five species are recorded here for the first time and include, Arca archiaciana, Exogyra plexa, Ceratostreon texanum, IIymatogyra areitina and Hyotissa semiplana.
Lithostratigraphy
Albian-Santonian strata of Wadi Qena can be subdivided into Malha (Early Albian); Galala Formation raised to the rank of group and subdivided into Raha (Latemost Albian-Middle Cenomanian) which is subdivided into the Abu Had, Mellaha and Ekma members; Abu Qada (Late Cenomanian-Early Turonian) which is subdivided into Lower carbonate, middle shale and upper carbonate members; Umm Omieyid Formation (Middle-Late Turonian) and Hawashiya Formation (Late Coniacian-Santonian).
Quantitative Biostratigraphy
Dating of the latemost Albian to Santonian platform succession is improved, mainly based on new biostratigraphic data of detailed investigations of ammonite, bivalve, gastropod and echinoid. These results can be integrated into overregional biozonation schemes. Quantitative biostratigraphy (Unitary associations) was applied for maximal stratigraphic resolution with a minimum of superpositional contradictions. Cluster analysis was applied also for enhancement and elucidation of the unitary associations distances. Integration of different biozonal schemes achieves reliability and standaralization for the biochronological scheme. This biozonation is intended for inter-regional correlation. Stages and Substages boundaries drawn according to the proposed biozonation.
The occurrence of the uppermost Albian horizon is recorded here in the study area for the first time supported by the typical Albian fauna for all macrofaunal groups. However, a major hiatus regard by an erosional surface at the base of Hawashyia Formatioin spanning the early Coniacian age in the study area requires extensive investigations in adjacent areas to complete the late Albian-Santonian biocheonological scheme.
Sequence Stratigraphy
A sequence stratigraphic model containing six sequence boundaries and six depositional 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, Jordan and Europe. Differences predominantly result from minor order sea-level changes and regional tectonics. Increased uplifting is mainly observed in the Eastern part of the study area, locally persisting from middle Cenomanian upward. Absence of the late Turonian sequence indicate local sea level falls start from the late Turonian and continued up to early Coniacian where a major hiatus occurs suggest sub aerial exposure. The detailed sedimentologic and sequence stratigraphic analysis of the uppermost Albian-Santonian strata of north Wadi Qena area, Eastern Desert, Egypt and correlation with the adjacent areas yielded the following results:
1. Six complete depositional sequences (DS I–DS VI) which indicates a cycle order intermediate between 3rd and 2nd can be recognized. The stratigraphic positions of these depositional sequences are as follows: DS I {Nucula (N.) margaritifera to Rhynchostreon suborbiculatum Zone} of latemost Albian-early Cenomanian age and it s comprises the Abu Had Member, Raha Formation. DS II {Ceratostreon flabellatum Zone} spans the middle Cenomanian and represents Mellaha Member, Raha Formation. DS III {Neolobites vibrayeanus to Metoicoceras geslinianum} spans the early-late Cenomanian comprises the lower carbonate Member of Abu Qada Formation. DS IV {Vascoceras cauvini to Mammites nodosoides Zone} comprises the middle and upper members of the Abu Qada Formation and represents late Cenomanin/early Turonian age. DS V {Choffaticeras segne to Coilopoceras requinianum Zone} spans the middle-late Turonian and comprises the Umm Omieyid Formation. DS VI {Meretrix plana to Texanites (T.) texanus Zone} comprises the Hawashiya Formation and it of late Coniacian-Santonian age.
2. Comparison with other basins elsewhere suggests the eustatic nature of most Cenomanian sea-level variations. In inner and mid-shelf settings, sequence boundaries are represented mostly by stratigraphic gaps and lowstand deposits are often absent. The second-order sea-level rise of the Cenomanian was accompanied by a stepwise deepening and concomitant withdrawal of terrigenous sediment and nutrient supply. Transgression of the Cenomanian Sea can be demonstrated by means of southward migration of coastal onlap; during maximum flooding of DS IV, Maximum transgression is indicated by the deposition of homogeneous pelagic sediments of the Limestones’ in the late Cenomanian of whole parts across north Eastern Desert and Sinai, the most proximal (southern) areas were also submerged. A major sea-level fall is recorded at the Early/ Coniacian boundary (SB V). Finally the studied sections represent the lowermost inner shelf environment.
3. Most of the ‘classic’ bioevents of Ernst et al., 1983 can be interpreted within the proposed sequence stratigraphic framework. Three main types of bioevents are recognized: ‘onlapping bioevents’ at the transgressive surface or in the early transgressive systems tract, ‘maximum flooding bioevents’, and ‘late highstand bioevents’. The development of ‘onlapping bioevents’ is related to the accumulation of biogenic hard parts as a result of winnowing during initial transgression or the incursion of water masses with ‘unusual’ physico-chemical properties (salinity, temperature) and contained ‘exotic’ faunal elements. ‘Maximum flooding bioevents’ are blooms of specialist taxa adapted to maximum flooding conditions (low-energy and oligotrophy with low food supplies for benthic fauna); they are relatively rare but often widely distributed. ‘Late highstand bioevents’ are shell concentrations in relatively coarse limestone that formed because of decreasing accumulation rates, winnowing of fines, and incipient condensation during late highstands of third-and fourth-order (highfrequency) sequences (decreasing accommodation space).
Faunal assemblages and Paleoecology
The macrofaunal categories employed to infer paleoenvironmental conditions. Collectively the methods of establishment of the optimum conditions for the Paleoecolgy are more precisely approached by analyzed the association grouply. The disappearance of many species and the general depletion of Oyster diversity in late Cenomanian deposits 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 are less important as carbonate producing organisms. Cenomanian assemblages of all groups are well comparable with those of other Tethyan realm areas. Raha Formation deposited under lower infralittoral condition with warm and moderate oxygenation water percentage, Abu Qada Formation was deposited under upper infralittoral to upper circalittoral environment with high temperate, low oxygen percentage and quite water conditions. Umm Omieyid Formation was settled in high agitated infralittoral environment with moderate temperature and oxygen percentage. Hawashiya Formation accumulates under upper infralittoral environment with normal oxygenation in arid conditions.
Environmental changes and Platform Crises
Supratidal to deep subtidal environments of deposition occur on the platform. Peritidal to shallow subtidal environments prevailed during most times, but their characterizing lithofacies types differ during the Cenomanian and Turonian. These differences are mostly related to biofacies changes, induced by the late Cenomanian global sea-level rise. This deepening also induced restricted deeper water environments, characterized by low energy and low oxygen conditions, organic carbon-rich deposits, and opportunistic benthic microfauna. This facies reflects a ‘platform crisis’ and is observed within the north Wadi Qena succession in the study area and coincide with a global middle Cenomanian sea-level rise and local black shale occurrences in adjacent shelf area (Israel and Jordan). Based on these results, small basins on the inner shelf are reconstructed for the mentioned areas.
Albian-Cenomanian boundary continuous with no change in the depositinal mode, while Cenomanian/Turonian boundary takes at the surface of maximum flodding, a great mass extinction for all macroinvertebrate fauna. A major hiatus at Turonian/Coniacian boundary suggest subarial exposure and represents an erosional surface at the base of hawashiya Formation. Coniacian/Santonian boundary characterize by return to homogenous condition and flourishing of macroinvertebrate fauna again
Paleogeography
The integrated stratigraphical and environmental investigations, reconstruct the distribution of facies belts and main structural elements on the north Eastern Desert and Sinai platform. comparing the lithofacies of the Albian Santonian of north Wadi Qena with north Eastern Desert and Sinai based on sedimentogies, biostratigraphies event stratigraphy and sequence stratigraphy indicate three different deposithional environments outer, middle and inner shelf.
Paleoceanography
Species richness and abundance of macroinvertebrates of the study area in relation to other environments indicate that the highest diversities and densities found in the middle than inner shelf this fact may be explained by two parameters: primary productivity and food quality .On the middle shelf, primary productivity was probably very high. In Cenomanian eutrophic inner and middle shelf areas, benthic biomass usually being coupled to organic carbon flux (food availability). The cause for the highest diversity and density of benthic stocks not directly inshore may have been related to food quality, which was probably better in inner and mid-shelf areas owing to reduced tidal resuspension of clay and silt materials.
Paleobiogeography and Migration
The paleobiogeographic distribution of these macrofaunal groups revealed that the Temperature, oxygenation, water circulation is the effective variables controlled distribution of these biota. Albian-Cenomanian fauna of tethyan affinities, although few taxa are cosmopolitan, while the Coniacian-Santonian ones are more indemic attributed to farther continental separation by this time.. Texanites (T.) texanus of late Santonian only regarded to be cosmopolitan. The geographic distribution of oyster from different provinces led to summarizing a migration trend started from Texas basin at the end of Albian age toward south Europe then to North Africa and later to Brazil and Peru. This migration trend was be influenced by plate tectonic motion of Africa and South America toward the north at the beginning of Late cretaceous.