Evolution of thrust system deformation in an intracratonic chain: Study of the Southern-Central Tunisian Atlas

The development of belt structures in intracratonic chains is guided by the convergence system. In the Southern-Central Tunisian Atlas, several parameters control the evolution of thrust folds during different tectonic phases. One of these phases is tectonic inheritance, which leads to the reactivation of pre-existing normal faults during compressive phases. The angle between the direction of these faults and the shortening axis (NNW-SSE) is the most important parameter for interpreting the mode of the evolution of thrust folds. Jebel Elkebar is an example of a structure developed on NW-SE-oriented faults that is perpendicular to the shortening axis. Based on the geometry of its folds, Jebel Elkebar is interpreted as a 'Fault Related Fold'. The E-W-oriented Orbata structure is oblique to the direction of the shortening axis and is interpreted through the model 'Fault Propagation Fold' with 'Breakthrough'. The Gafsa Fault, which is parallel to the shortening axis, is a transpressional fault interpreted through the 'Strain Partitioning' mode, which is associated with the oblique ramp fold. The development of various thrust folds requires the presence of a basal decollement level during the Triassic succession. In the Southern-Central Tunisian Atlas, the deformation is variable (geometry of fold closure) and is correlated with the depth of the decollement level; indeed, the intensity of deformation is proportional to the depth of the decollement level. Consequently, the most important deformation is in the higher successions and is a vertical migration of the decollement level associated with thin-skinned deformation.     

Contribution of satellite altimetry data in the geophysical investigation of the Red Sea Region, Egypt

Successful development of geodetic satellite missions has aroused new interest in determining global and regional gravity field based on satellite data. Satellite altimetry data enable direct determination of the geoid over sea regions. In Egypt, where land and marine geophysical data are inadequate because of rough topography and economic reasons, the use of satellite altimetry data is of special importance. The northern Red Sea region has been selected as a site for case study of the current research, after applying spectral analysis to reveal near-surface structure, the residual geoid of the studied region shows a good correlation with the known geologic features. Moreover, satellite-based gravity data enhance small-scale features and agrees well with land and marine gravity data. Thus, geoid undulation and satellite gravity data can be a complementary source of data to determine near-surface and deep structures.     

Developing artificial neural network models to predict allowable bearing capacity and elastic settlement of shallow foundation in Sharjah,United Arab Emirates

This research proposes the use of artificial neural network to predict the allowable bearing capacity and elastic settlement of shallow foundation on granular soils in Sharjah, United Arab Emirates. Data obtained from existing soil reports of 600 boreholes were used to train and validate the model. Three parameters (footing width, effective unit weight, and SPT blow count) are considered to have the most significant impact on the magnitude of allowable bearing capacity and elastic settlement of shallow foundations, and thus were used as the model inputs. Throughout the study, depth of footing was limited to 1.5 m below existing ground level and water table depth taken at the level of the footing. Performance comparison of the developed models (in terms of coefficient of determination, root mean square error, and mean absolute error) revealed that the developed artificial neural network models could be effectively used for predicting the allowable bearing capacity and elastic settlement. As such, the developed models can be used at the preliminary stage of estimating the allowable bearing capacity and settlements of shallow foundations on granular soils, instead of the conventional methods.     

Groundwater condition based on geoelectrical technique and Dar Zarrouk parameters between El Alamein and El Dabaa—Egypt

El Alamein-El-Dabaa area lies in the western Mediterranean coastal zone of Egypt with about 50 km long. The aims of the present study are the shallow groundwater aquifer determination and calculate the electric parameters of the overburden to achieve the easiest way for detecting groundwater contamination and considered it during the planning of new development project(s). To attain this target, 44 vertical resistivity soundings using Schlumberger array of the maximum AB/2?=?1000 m in the form of four profiles were carried out. From the interpretation results, six geoelectrical layers have been established in the area, and iso-resistivity, depth to water, and isopach contour maps are presented. Four geoelectrical cross-sections (two geoelectrical cross-sections are parallel to the Mediterranean shoreline and the other two are normal to the Mediterranean shoreline) have been constructed. According to this work, the upper part of the Oolitic Limestone represents the shallow groundwater aquifer in this area and can be distinguished into two zones. The upper zone is brackish, whereas the lower one is saline. The geoelectrical succession reveals that the aquifer is free type. The depth to water ranges between 20 and 63 m; therefore, it is the choice as the best sites for groundwater exploitation. In the area under study, the depth to water and the thickness of the brackish increase towards the south side as well as the depth to the brackish water. The Dar-Zarrouk parameters clarified that there are some parts that may contaminate pathways and other parts are not.     

Monophyly or polyphyly? Possible conflict between morphological and molecular interpretations of the wellknown genus Zoothamnium(Ciliophora,Peritrichia)

In this paper,we explore possible conflict between morphological and molecular interpretations of phylogenetic relationships within the well-known peritrichous genus Zoothamnium. On the basis of morphological evidence,for a long time this genus has been believed to be a well-defined monophyletic taxon. Nonetheless,Z oothamnium exhibits higher genetic diversity than the gross morphology of its species. Here,we used all available genetic information for the small subunit of ribosomal RNA(SSU r RNA) and internal transcribed spacer region(ITS1-5.8S-ITS2) for this genus to reconstruct phylogenies for four datasets(SSU rRNA,ITS1,ITS2,and ITS1-5.8S-ITS2) and a combined dataset(SSU rRNA+ITS1-5.8SITS2) using different phylogenetic methods and with consideration of the secondary structure of the genes. Confidence in phylogenetic tree selection was assessed with the approximately unbiased test. The molecular results showed both that Zoothamnium is more likely to be polyphyletic,and morphologically similar genera Zoothamnopsis and Myoschiston were always nested among Zoothamnium species. Accordingly,as with some other groups of ciliates,to understand more fully the correct phylogeny of Zoothamnium there remains a need for additional data from both morphological and molecular studies,covering additional Zoothamnium spp. and members of closely related genera(e.g. Zoothamnopsis,Myoschiston,and Epistylis).     

The 2014 seismic hazard model of the Middle East: overview and results

The Earthquake Model of Middle East (EMME) Project aimed to develop regional scale seismic hazard and risk models uniformly throughout a region extending from the Eastern Mediterranean in the west to the Himalayas in the east and from the Gulf of Oman in the south to the Greater Caucasus in the North; a region which has been continuously devastated by large earthquakes throughout the history. The 2014 Seismic Hazard Model of Middle East (EMME-SHM14) was developed with the contribution of several institutions from ten countries. The present paper summarizes the efforts towards building a homogeneous seismic hazard model of the region and highlights some of the main results of this model. An important aim of the project was to transparently communicate the data and methods used and to obtain reproducible results. By doing so, the use of the model and results will be accessible by a wide community, further support the mitigation of seismic risks in the region and facilitate future improvements to the seismic hazard model. To this end all data, results and methods used are made available through the web-portal of the European Facilities for Earthquake Hazard and Risk (www.efehr.org).     

Late Ediacaran post-collisional A-type syenites with shoshonitic affinities,northern Arabian-Nubian Shield: a possible mantle-derived A-type magma

The Abu Rumeil syenitic rocks represent the inner ring dyke of the Katherina Ring complex, southern Sinai, Egypt. They are divided petrologically into two types, alkali feldspar syenite and quartz syenite. The mineralogy and geochemistry of the syenites indicate an alkaline nature with a shoshonitic affinity. Although rare mafic xenocrysts overgrown by primary K-feldspars and overlapping rare earth element (REE) patterns indicate some role for crustal contamination, the trace element chemistry shows a dominant mantle contribution. The geochronology and field relations imply that the Abu Rumeil syenites were emplaced in a post-collisional, within-plate tectonic setting, yet they express the enrichments in large-ion lithophile elements relative to high field strength elements generally characteristic of subduction influence. We suggest that this signature is inherited from partial melting of a lithospheric mantle source previously affected by subduction during assembly of the Arabian-Nubian Shield. Little evidence of the early evolution of the suite is preserved; there are no associated mafic rocks. We therefore restrict our attention to a petrogenetic model that can explain the relations among the observed felsic composition. The REE patterns of all samples are enriched in light REE and fractionated, but it is notable that there are small positive Eu anomalies in the alkali-feldspar syenites contrasting with small negative Eu anomalies in the quartz syenites. Positive Eu anomalies suggest a cumulate nature for the alkali-feldspar syenites; there are also breaks in the slopes of most variation trends between the alkali-feldspar syenites and the quartz syenites. The general trends in all major oxides and trace elements within the suite can be modeled by fractional crystallization of feldspars—with smaller roles for pyroxene, biotite, apatite, and Fe-Ti oxides—from an intermediate liquid to form the quartz syenites and by assimilation of the near-liquidus phases into the same starting liquid to form the alkali feldspar syenites. The geothermobarometry of pyroxenes and amphiboles suggests shallow emplacement (<10 km depth) and crystallization temperatures ranging from 1100 °C down to 800 °C.     

New analytical solution of the dispersion equation

The dispersion of pollutants from a point source is analytically investigated taking into consideration the vertical variation of both wind speed and eddy diffusivity. The deposition of the diffusing particles on the ground is taken into account throughout the boundary conditions. The concentration of pollutants under different atmospheric stabilities was found assuming that the vertical diffusion is limited by an elevated inversion layer. The decay distance of a pollutant along the wind direction for different atmospheric stabilities was derived. The resulting analytical formulae have been applied on a case study namely, the emission from the research reactor at Inshas. The results are discussed and presented in illustrative figures.     

Geochemical behaviour of the Tunisian background aerosols in Sirocco wind circulations

This study examines spatial and time evolutions of the principal constituents of the Tunisian background aerosols under Sirocco wind circulations. Aerosols coming from the Sahara Desert were found to be loaded with particulate matter, especially silicon. The aerosols were shown to have varying geochemical behaviour along the ``South-North" displacement of the Saharan plumes, depending on the wind flow characteristics, geomorphologic features and the nature of soils swept by the wind. In the south and the center part of the country, the transfer of aerosol constituents to the soil (by gravity and/or impaction) was probably predominated by localized enrichment phenomena. The latter are reinforced by the effect of turbulent winds over bare soils, wind wakes and probably selective disintegration, especially in the vicinity of the geomorphologic features of central Tunisia. These relatively high features, extending over important distances, appear to be of paramount importance for the phenomena of redistribution of aerosol constituents even during periods without Sirocco wind circulations. In the northern section of the country, aerosol constituent concentrations dropped to almost 50%, in spite of the abundance of localized turbulent winds. This may be explained by the effect of forests and the relatively dense vegetation cover, which clearly reinforces the transfer phenomena to the soil and the attenuate of dust entrainment.     

Pharaonic necrostratigraphy: a review of geological and archaeological studies in the Theban Necropolis, Luxor, West Bank, Egypt

We present a review of archaeological and geological studies on the West Bank as a basis for discussing the geological setting of the tombs and geologically related problems with a view to providing archaeologists with a framework in which to conduct their investigations on the restoration, preservation and management of the antique monuments. Whereas the geology of the Upper Nile Valley appears to be deceptively simple, the lithological succession is vertically variable, and we have recognized and defined several new lithological units within the upper Esna Shale Formation. We have been able to delineate lithological (shale/limestone) contacts in several tombs and observed that the main chambers in some were excavated below the Esna Shale in the Tarawan Chalk Formation. We have been able to document changing dip in the strata (warping) in several tombs, and to delineate two major orientations of fractures in the field. Investigations behind the Temple of Hatshepsut, in the Valley of the Kings and around Deir El Medina have revealed four broad regional structures. We confirm that the hills located near the Nile Valley, such as Sheik Abdel Qurna, do not belong to the tabular structure of the Theban Mountain, but are discrete displaced blocks including the Thebes Limestone, as supported by Google Earth photographs.