Mineralogical and geochemical characterization of listwaenite from the Semail Ophiolite, Oman

The late Cretaceous-lower Tertiary hydrothermal alteration of serpentinized peridotite in the Semail ophiolite has formed two distinct types of listwaenite. Type I is characterized by the presence of calcite (Type IA) or dolomite (Type IB)+fuchsite±spinel. Type II is dominated by silicate minerals (quartz, chlorite, fuchsite)±calcite+dolomite±magnetite±apatite±plagioclase. Most listwaenites occur as veins along thrust fault zones within the ophiolite mélange. High Cr and Ni contents, abundant occurrence of Cr-spinel within a matrix of red-brown ferruginous carbonates within a micro-vein network of goethite, and the relics of mesh texture indicate an ultramafic protolith. Type I and II listwaenites represent different stages of hydrothermal alteration. The mineralogical and chemical distinctions of both types are the response to the extent of the reactions between the protoliths and the solutions leading to different stages of metasomatic replacement. The hydrothermal fluids involved in the formation of Type I listwaenite were enriched in Ca, Mg, and CO₂, whereas Type II listwaenite bodies were formed from a hydrothermal fluid enriched in SiO₂. REE and trace elements in both listwaenite types were extracted in part from adjoining peridotite. No Au anomaly in the study areas has been detected.     

Vulnerability mapping of shallow groundwater aquifer using SINTACS model in the Jordan Valley area, Jordan

Jordan Valley is one of the important areas in Jordan that involves dense agricultural activities, which depend on groundwater resources. The groundwater is exploited from an unconfined shallow aquifer which is mainly composed of alluvial deposits. In the vicinity of the Kafrein and South Shunah, the shallow aquifer shows signs of contamination from a wide variety of non-point sources. In this study, a vulnerability map was created as a tool to determine areas where groundwater is most vulnerable to contamination. One of the most widely used groundwater vulnerability mapping methods is SINTACS, which is a point count system model for the assessment of groundwater pollution hazards. SINTACS model is an adaptation for Mediterranean conditions of the well-known DRASTIC model. The model takes into account several environmental factors: these include topography, hydrology, geology, hydrogeology, and pedology. Spatial knowledge of all these factors and their mutual relationships is needed in order to properly model aquifer vulnerability using this model. Geographic information system was used to express each of SINTACS parameters as a spatial thematic layer with a specific weight and score. The final SINTACS thematic layer (intrinsic vulnerability index) was produced by taking the summation of each score parameter multiplied by its specific weight. The resultant SINTACS vulnerability map of the study area indicates that the highest potential sites for contamination are along the area between Er Ramah and Kafrein area. To the north of the study area there is a small, circular area which shows fairly high potential. Elsewhere, very low to low SINTACS index values are observed, indicating areas of low vulnerability potential.     

Gravitational drainage systems in urban areas: case study (Galaţi town, Romania)

The water leakage in the urban areas causes a continuous rise in the water table, with harmful effects. An experimental drainage system, based on horizontal well technology, was designed and implemented in a populated area. Groundwater flow modeling was used to assess the hydrodynamic efficiency of the system through drain conductance parameter estimation.     

Seasonal cycle of hydrography in the Bab el Mandab region,southern Red Sea

The seasonal cycle of temperature—salinity variations in the Bab el Mandab region (southern Red Sea) is described using CTD data collected during four cruises spread over the period May 1995—August 1997. A two layer system exists during early summer, winter and spring while a three layer system exists during summer. During summer, a large amount of the Gulf of Aden water intrudes into the Bab el Mandab region; up to the northern limit (14.5‡N). The quantity of Red Sea water that flows into the Gulf of Aden is maximum during the winter and minimum during the summer     

Late Eocene marginal marine deposits and paleoenvironment characterisation from the Maadi Formation (Northern Eastern Egypt)

Two beds containing relatively thick and highly concentrated oyster shell banks occurring in the densely fossiliferous Wadi Al Abraq outcrop (Upper Eocene Maadi Formation, Cairo-Sukhna Road, Egypt). Such shell beds are almost monospecific. The upper level consists mainly of Ostrea clotbeyi Bellardi, topped by a considerable concentration of Carolia placunoides Cantraine, while in the lower level occurs Ostrea multicostata Deshayes. In both beds, the upper contact with the overlying marl bed (about 2 m thick) is sharp and sometimes erosive. Similarly, the contact with the underlying shale (1.5 m thick) is sharp and erosional. The shell beds are composed mainly of loosely packed oyster shells and their fragments (usually with a high proportion of disarticulated specimens) set in the sandy limestone matrix. The collected oysters show bioerosion and skeletobiont assemblages. Bioerosion trace fossils comprise ten ichnospecies while skeletozoans comprise five taxa. In general, shells of O. clotbeyi show a higher incidence of bioerosion than O. multicostata. The shells' chaotic orientation and their moderate fragmentation indicate that the shell bed formation was associated with high energy events. On the other hand, the low frequency of articulated specimens suggests that the shell beds are parautochthonous oyster banks' remnants. The taphonomic features of the studied assemblage indicate deposition in a shallow-water, wave-dominated environment.     

Monitoring of 45 pesticides in Lebanese surface water using Polar Organic Chemical Integrative Sampler (POCIS)

The aim of this study is to assess the dissolved concentration of 45 pesticides in the surface waters of the Lebanese Republic using Polar Organic Chemical Integrative Sampler "POCIS". All of the sampling sites are located in the major agricultural land areas in Lebanon. POCIS (n = 3) were deployed at Ibrahim River, Qaraoun Lake and Hasbani River for a duration of 14 days. The total concentration of pesticides ranged from not detected (nd) to 137.66 ng.L^-1. Chlorpyrifos, DDE-pp, diazinon and Fenpropathrin were the most abundant compounds. Qaraoun Lake and Hasbani River were found to be more polluted than Ibrahim River, since they receive large amounts of waste water derived from nearby agricultural lands and they had the lowest dilution factor. The aqueous average concentration of the target compounds were estimated using sampling rates obtained from the literature. Comparison between Time Weighed Average concentrations "TWA" using POCIS and spot sampling is presented. Results showed that POCIS TWA concentrations are in agreement with spot sampling concentrations for Ibrahim and Hasbani Rivers. The toxicity of the major detected pesticides on three representative aquatic species (Daphnia magna, Scenedesmus quadricauda and Oncorhynchus mykiss) is also reported.     

<Emphasis Type="Italic">Suraqalatia brasieri</Emphasis> n.gen., n.sp. (larger foraminifera) from the Maastrichtian of Sulaimani area in northern Iraq

Suraqalatia brasieri n.gen., n.sp. from the family Dicyclinidae Loeblich and Tappan 1964 occurs on the Maastrichtian carbonate platform of northern Iraq. The new genus is recognizable by its large very compressed conical test, up to 55–70 mm in diameter, to 0.3–1.6 mm in thickness, planspiral cooling having very small proloculus in the initial part and later circular chambers including numerous chamberlets with an agglutinated wall. Suraqalatia brasieri n.gen., n.sp. is associated with textulariids, miliolids and rotaliids as Loftusia elongata Cox, L. morgani Douvillé, Orbitoides medius d’Archiac, O. megaloformis Papp & Kupper, O. gruenbachensis Papp, O. apiculatus Schlumberger, Omphalocyclus macroporus (Lamarck), Siderolites calcitrapoides Lamarck, Sirtina orbitoidiformis Brönnimann & Wirz. The associated macrofauna comprises large and rich giant rudists (Preradiolites sp.), other bivalves (Gryphaea sp. and Glycymeris sp.), gastropods (Acteonella sp.), echinoderms and corals. The fauna indicates shallow marine carbonate platform conditions within the Maastrichtian green house. It is also worth mentioning that the new genus has only been recorded from the Maastrichtian age.     

Applications of variogram modeling to electrical resistivity data for the occurrence and distribution of saline groundwater in Domail Plain,northwestern Himalayan fold and thrust belt,Pakistan

This paper studies electrical resistivity dataset acquired for a groundwater study in the Domail Plain in the northwestern Himalayan section of Pakistan. Through a combination of geostatistical analysis, geophysical inversion and visualization techniques, it is possible to re-model and visualize the single dimension resistivity data into 2D and 3D space. The variogram models are utilized to extend the interpretation of the data and to distinguish individual lithologic units and the occurrence of saline water within the subsurface. The resistivity data has been calibrated with the lithological logs taken from the available boreholes. As such the alluvial system of the Domail Plain has formed during episodes of local tectonic activity with fluvial erosion and deposition yielding coarse sediments with high electrical resistivities near to the mountain ranges and finer sediments with medium to low electrical resistivities which tend to settle in the basin center. Thus a change is depositional setting happened from basin lacustrine environment to flash flooding during the Himalayan orogeny. The occurrence of rock salt in the northern mountains has imparted a great influence on the groundwater quality of the study area. The salt is dissolved by water which infiltrates into the subsurface through the water channels. Variogram aided gridding of resistivity data helps to identify the occurrence and distribution of saline water in the subsurface.