Remote sensing of paleodrainage systems west of the Nile River,Egypt

Remotely sensed data show details of the geomorphic features and landscape evolution west of the Nile. The detected features include remnants of paleochannels, flutes and rock-mass movements. Fused radar/optical data, altitudinal profiles and 3D perspective view provided evidences of massive landslides that fully blocked the earlier Nile channel near to the Western Desert plateau. This channel was ~30 km west of the present Nile at ~100 m above the present level of the Nile. Subsequently, the fluvial activities shifted about ~10 km eastward, leaving behind several remnants of paleochannels, fluvial deposits, ancient landscape and Nilotic fauna. The automatic extraction of stream networks clearly depicts the developments of paleochannels. Our results revealed that fluvial activity switched from the Gallaba plain to the present Nile course through a series of tectonic and climatic changes. Furthermore, integration of radar and optical images provided an explanation for causes of the undulated forms ‘flutes’.     

Alam El Bueib reservoir characterization,Tut oil field,North Western Desert,Egypt

An integrated petrophysical well log and core data analysis of the Alam El Bueib-3D (AEB-3D) and Alam El Bueib-3E (AEB-3E) reservoirs, Tut oil field, North Western Desert, Egypt, allows the evaluation of those parameters critical to their reservoir characterization. The determined reservoir properties investigated are lithology, depositional paleoenvironments, shale volume, porosity, fluid saturation and net pay thickness. As the analysis of reservoir pressure is essential to specify the driving mechanisms that control the behavior of fluids within reservoirs, pressure analysis identified the Alam El Bueib-3D reservoir to be partial water drive and Alam El Bueib-3E to be an active water drive. In addition, the pressure analysis identified two additional hydrocarbon-bearing reservoirs in the Alam El Bueib-3D. Stacking patterns of the Alam El Bueib-3D reservoirs are generally fining upward sequences reflecting fluvial to braided fluvial paleoenvironments. The Alam El Bueib-3E channel shows blocky patterns with sharp bases and tops diagnostic of distributary channels. Statistical analysis of core permeability and porosity values of the Alam El Bueib reservoirs indicate very good reservoir quality. Scatter diagrams of porosity values derived from core analysis for the AEB-3D and AEB-3E reservoirs reveal correlation coefficient (r) values of 0.93 and 0.64, respectively, indicating strong linear relationships. Plots of porosity values against permeability values also show strong linear relationships in all the reservoirs indicating that the AEB-3D and the AEB-3E are permeable and with strong pore communication. The permeability measurements indicate restricted reservoir heterogeneity as plots of vertical permeability values against horizontal permeability values exhibit linear trends. Altogether, the reservoir characterization of the Alam El Bueib reservoirs demonstrates their excellent potential for hydrocarbon production.     

Structures controlling U and Th mineralisation in the Gebel Felat area of the south Eastern Desert of Egypt

In the Eastern Desert of Egypt, younger granites host U and Th mineralisations which are concentrated along faults and joints. In particular, the Gebel Felat Pluton is characterised by a high level of radioactivity as shown by an aeroradiometric survey. The U content is 82 ppm and the Th content is 15 ppm in areas of high radioactivity. The rocks are cross-cut by two main sets of fractures trending east-west and northwest-southeast. The contour maps of these two trends can be correlated with the aeroradiometric map of the same area.     

Expected damage from displacement of slow-moving slides

Facilities such as buildings, highways, railways, bridges, dams and pipelines often are built on natural slopes where the risk of landslides is not low. The vulnerability of these facilities to slow-moving slides has sometimes been underestimated, although the velocity of some classes of slow slides is uncontrollable. More than 50 cases of slow slides were compiled from the literature for this study. Some statistics about the movement trigger(s), the methods used to measure displacement, the material forming the rupture surface and the type of the vulnerable facilities are presented. It is shown that the expected degree of damage to urban settlements, highways, bridges and dams can be related to the slide velocity or accumulating displacement. Buildings and residential houses may tolerate higher slide velocities and total displacements than other facilities before experiencing serious damage. Movements as low as 100 mm may severely damage bridges, but such low rates may cause only moderate damage to urban communities. The relationship between movement and the expected extent of damage should be useful to geotechnical engineers who deal with different classes of slow slides and will help in the choice of appropriate mitigation measures based on preliminary estimates of movement rates.     

New contributions to the Upper Senonian stratigraphy in Northern Iraq

The Upper Senonian sediments are well developed in Northern Iraq and represent three types of facies; elastics, reefal, and open-marine. These sediments are classified stratigraphically depending upon similarities in age and lithology. New groups are proposed for the first time; Ruwanduz Reefal Group comprising Aqra Limestone Formation, Bekhme Limestone Formation and Pilsener Limestone Formation, and Zakho Marl Group including Shiranish Formation, Digma Formation and Jib'ab Formation. It is suggested here that Jib'ab Formation is an extension of the Shiranish Formation and should not be treated as a separate lithostratigraphic unit.     

Facies associations of the Bathonian Hamam Formation from Northwestern Jordan

Two stratigraphic sections of the Hamam Formation (Bathonian Stage, Middle Jurassic) exposed in the western part of Wadi Zarqa region, northwestern Jordan, are described and interpreted on the basis of palynoflora and facies analysis in order to reconstruct their depositional environments and sequence stratigraphic framework, which not discussed before. Five facies associations have been identified in the Hamam Formation characterized by a mixed carbonate–siliciclastic ramp setting, ranging from incised fluvial valley fill facies, beach foreshore restricted inner ramp to high-energy shoals and mid-ramp settings. The palynoflora includes well-preserved miospore assemblages which are recorded only from the incised fluvial valley fill facies for the first time and yielded 64 miospore species belonging to 40 genera. Most of these taxa are long-ranging and have been reported from Jurassic and Cretaceous rocks worldwide, except Callialasporites dampieri, Murospora florida, Granulatisporites jurassicus, Piceites expositus, Pityosporites parvisaccatus, Leptolepidites verrucatus, and Protopinus scanicus which have short ranges in the Middle Jurassic. Furthermore, these rocks are rich in shallow-marine Neo-Tethys macro-invertebrates supporting a Bathonian age. Two third-order depositional sequences bounded by three regional unconformities at the Bajocian–Bathonian and Bathonian–Callovian stage boundaries as well as within the Bathonian are defined based upon facies characteristics and stratal geometries. A regional correlation of sequence boundaries of similar age indicates that they are eustatic in origin.     

Calcareous nannofossil biostratigraphy of the Paleocene at the Misheiti section,East Central Sinai,Egypt

Integration of calcareous nannofossil data, δ¹³C and δ¹⁸O values, and carbonate contents of the lower Paleocene–upper Paleocene sequence that crops out at the Misheiti section, East Central Sinai, Egypt, were used to denote the Danian/Selandian (D/S) and Selandian/Thanetian (S/T) stage boundaries. The study interval belongs to the Dakhla and Tarawan formations. Four calcareous nannofossil zones (NP4, NP5, NP6, and NP7/8) were recognized. The base of the Selandian Stage is tentatively placed at the lowest occurrences (LOs) of taxa ascribable to the second radiation of fasciculiths (i.e., Lithoptychius janii). This level is marked by a sudden drop of δ¹³C and δ¹⁸O values and carbonate content. No distinctive lithological changes were observed across the D/S boundary at the study section. A hiatus at the NP5/NP6 zonal boundary is indicated by the condensation of zones NP5 and NP6.The base of the Thanetian is placed at the base of Zone NP7/8 at the lithological change observed in correspondence to the boundary between the Dakhla and Tarawan formations. The δ¹³C and δ¹⁸O values abruptly decrease slightly above the base of Zone NP7/8. No consistent variations in the carbonate contents were recorded within Zone NP6 or across the NP6/NP7/8 zonal boundary.     

Very short-term behaviour of the flare star EV Lac

Sinusoidal variations in Johnson'sB-band of the flare star EV Lac have been confirmed at its quiet state luminosity. The cycle lengths are more than one hour and less than two hours with amplitudes varying from 0 _. ^m 105 to 0 _. ^m 306. These registered cycles have agreed with cycles detected by Mavridis and Varvoglis (1990) and Mavridis (1990). In the same time, the cycles have confirmed the light variation detection in Johnson'sV-band in the same flare star by Pettersen (1980) with a cyclic period equals about 4 _. ^d 378 and an amplitude of about 0 _. ^m 07. Our net results confirm, to some extent, the presence of active region(s) as an origin of stellar flare phenomenon of UV Ceti type flare stars. We can cautiously say that the solar and stellar flare phenomenon have a similar origin.