3-D magnetic inversion and satellite imagery for the Um Salatit gold occurrence,Central Eastern Desert,Egypt

The Um Salatit is a gold occurrence situated in the Central Eastern Desert of Egypt. The studied area is characterized by an intensive imbrication zone of serpentinites and metavolcanic rocks. The integrated use of aeromagnetic and spectral reflectance remote sensing data has proved effective for mapping geology related to ore deposits. Spectral reflectance maps have been produced to discriminate various rocks, such as serpentinites, gabbros, and metavolcanic rocks. 3-D inversion of aeromagnetic data acquired over the Um Salatit study area produced a 3-D magnetic susceptibility model showing magnetic bodies surrounded by less magnetic host rock. The magnetic features are elongated ENE-WSW parallel to the major thrust fault and mapped the Um Salatit serpentinized rocks. Remote sensing data allow investigating surficial geological features and mapping the mineralized areas. Remote results, in conjunction with 3-D inversion of aeromagnetic data, demonstrate that gold occurrence in the study area was effectively restricted to the highly magnetic zone interpreted as host rocks.     

Characterization of Ain M’Dheker clay deposits for sunflower oil and Acid Black 194 dye clarification

Three mixtures (M1, M2, and M3) of the Eocene clay deposits were collected from Ain M’Dheker (Enfidha, Tunisia). These mixtures have been treated by hydrochloric acid in order to improve their physico-chemical characteristics. Optimum conditions for activation were conducted by varying several parameters such as the acid concentration, time, and temperature activation. The activation condition effect on surface area is studied. A representative raw (M3) and activated (AM3) mixtures were used in industrial application: Sunflower oil and Black 194 dyes (textile waste). M3 and AM3 were used to leach sunflower oil by varying the clay amount introduced. Results of the bleaching power of used samples were compared to that found by commercial bentonite imported from Germany (Tonsil), having a surface area of 725 m²/g. Indeed, an amount of 1% of AM3 gives a 60% decolorization similar to that found by commercial clay. Also, the ability of raw and activated clay to remove the dye (Acid Black 194) from effluent has been studied firstly at different pH and in second time by varying the adsorbent amount. Then, an amount of 0.025 g is sufficient to give a higher adsorption capacity for M3 than AM3. Consequently, Ain M’Dheker clay deposits can be use in other environmental application even without any treatment.     

Secondary dispersion of trace elements in bottom sediments of the High Dam Lake,South Egypt and North Sudan

Thirty-four chemical elements, pH, total nitrogen, and total organic carbon were determined in 49 bottom sediment samples from the whole High Dam Lake in order to improve our understanding of geochemical characteristics of these sediments and geochemical patterns of trace elements and related feeding sources. The present study revealed that the lake were clearly discriminated into three portions in accordance with the sediment geochemistry and geographic position. Likewise, the analyzed elements in the entire lake sediments were classified into six geochemical association patterns that are indicative of the contributing geogenic and anthropogenic sources. As has been noted here, mineralogy, anthropogenic inputs, pH, and organic matter had significant roles in controlling the behavior, concentration, dispersion, and geochemical patterns of the trace elements in the lake sediments. Consequently, the elevated concentration of Bi, Cd, Co, Cr, Cu, Fe, Ga, Mn, Mo, Ni, Sc, V, Y, and Zn posed moderate contamination level in the sediments. At the same time, the enhancement of Ag, Se, and Te levels caused contamination up to very high levels. Admittedly, the contamination levels were generated by natural and human activities that are coming from the Nile basin countries. Despite progressive deterioration of these sediments, they still have economic applications.     

Agglutinated foraminifera from the Campanian-Maastrichtian Kiseiba Formation in the Kurkur area,Egypt

The upper Campanian to upper Maastrichtian sedimentary sequence of the Kiseiba Formation in south Western Desert is sampled and described in two surface sections (Sinn El Kaddab and Wadi Abu Siyal). Forty-four agglutinated foraminiferal species are identified from 42 samples in the studied succession. The benthic foraminiferal assemblages are dominated by agglutinated foraminifera which comprise more than 90% of the assemblage. The agglutinated foraminifera are subdivided into five morphogroups (A, B, C, D, E) according to shell architecture, integrated with the supposed microhabitat and feeding strategy. The foraminiferal assemblage is assigned to mixohaline shallow water environments. These assemblages with Ammoastuta megacribrostomoides and Ammotium bartheli suggest lagoonal environments with considerably reduced salinity in warm climates and high runoff for the late Campanian-Maastrichtian interval.     

Spatial distribution of regionalized variables on reservoirs and groundwater resources based on geostatistical analysis using GIS: case of Rmel-Oulad Ogbane aquifers (Larache,NW Morocco)

In many countries of the world, groundwater is the main source of water in arid and semiarid regions. The scarcity of water is one of the main issues in Morocco. The coastal aquifer system of Rmel-Oulad Ogbane is recognized as one of the most important aquifers in Morocco and is very well known for their role in industrial, economic, and social development. However, this role is confronted to climate change impacts and heavy abstraction rates leading to a major decline in the groundwater levels and may eventually cause a deficit water balance of the aquifer as well as a degradation of the freshwater quality by seawater intrusion. The objective of this research is to identify and evaluate the distribution and spatial changes of regionalized variables on reservoirs and groundwater resources using geostatistical analysis in Geographic Information System (GIS) software. The prediction of these variables was performed using an interpolation method: ordinary kriging in a GIS. The normality test and trend analysis were applied to each variable to select the appropriate semivariogram model (SVM) and check the results using cross-validation (CV). Hence, several kriged maps of reservoirs and water resources have been produced to be exploited by the decision maker. The studied variables related to reservoirs and hydrodynamic data have a strong spatial dependence, which show correlations in specific direction, while the hydrochemical data are mainly related to groundwater mechanisms, such as advective-diffusive transport, without any autocorrelation between data.     

Hydrocarbon-generating potential of the Eocene Thebes Formation,Gulf of Suez: 1D basin modeling as a supplementary tool for source rock evaluation

The present work provides high-resolution modeling of the thermal maturation of the Eocene Thebes Formation using a multi-1D approach. The model focuses not solely on the thermal maturity but also on timing of hydrocarbon generation (primary generation and secondary cracking), adsorption by organic matter, and expulsion. The time-lapse conceptual model was developed using well log data, geochemical analyses, and composite logs. The stratigraphic sequence of the Belayim Marine oil field was subdivided into a time series based on the tectonic framework of the Gulf of Suez. An elevated basal heat flow has been assigned throughout the rifting phases and basin evolution. The simulation developed for seven wells reveals variations in burial, thermal history, and accordingly the thermal maturity. The predicted thermal maturity ranges from immature to mature with a different tendency to generate hydrocarbons (both primary generation of oil and/or gas secondary cracking) dependent on kerogen type, basin development, and burial history. Hydrocarbon generation (oil) starts after the Messinian Time Event during the deposition of the Post-Zeit Formation. Hydrocarbon generation was related to burial rather than basin evolution for the 113-M-27, BM-23, BM-65, and BM-70 wells. Conversely, generation correlated principally to basin development particularly Messinian Time Event for the 113-M-34 well. Expulsion occurred subsequent to generation of thermogenic gas (secondary cracking of generated oil). It is not possible to investigate the relationship between the production index and thermal maturity as a consequence of expulsion that reduced the S1 values. The different levels of thermal maturity (potential, active, and effective source rock) allow for the differentiation of regions of potential hydrocarbon accumulation that were charged from the Thebes Formation.     

Planning and systematic management of water resources by the WEAP model,case of the Mabtouh watershed (northwestern Algeria)

Water management remains a complex task due to the multiplicity of users-consumers, which necessitates the use of planning tools and decision support in a rigorous manner. The objective of the present study is to find an alternative solution to the water use conflict applied to a scale of a hydrographic unit. Our choice focused on the Mebtouh River watershed (1306 km²), where there is a chronic water shortage. With an irrigated perimeter of 8200 ha and an urban area with a regional dimension, the hydraulic system is based on a Dam (Cheurfa) with a capacity of 83 hm³ and diversions by pumping over the river. The methodology adopted is the application of the WEAP software, with a view to constructing a water resource allocation model by 2050. The data set consists of the physical parameters of the study area, hydroclimatic records for the reference year (2015), and the estimation of urban and agricultural water demand sites. The results obtained by the WEAP model applied to our study area confirm the validation of the data used. Therefore, it is timely to develop a water resources management tool to reduce user-consumer tensions at the planned planning timeline.     

Hydrochemical constraints between the karst Tabular Middle Atlas Causses and the Saïs basin (Morocco): implications of groundwater circulation

The karst Tabular Middle Atlas Causses reservoir is the main drinking-water supply of Fez-Meknes region (Saïs Basin) in Morocco. Recent analyses showed a decline in associated groundwater chemical quality and increased turbidity. To understand this hydrosystem, four surveys were undertaken during fall and spring, 2009–2011. Hydrogeochemical studies coupled with isotopic analyses (δ¹⁸O, δD and ²²²Rn) showed that the aquifers between the causses (mountains) and the Saïs Basin are of Liassic origin and at the southern extremities are of Triassic origin. Five recharge zones of different altitudes have been defined, including two main mixing zones in the south. Deuterium excess results suggest local recharge, while a plot of δ¹⁸O versus δD characterizes a confined aquifer in the eastern sector. ²²²Rn results reveal areas of rapid exchanges with an upwelling time of less than 2 weeks. A schematic conceptual model is presented to explain the groundwater circulation system and the behavior of this karst system.