A geoelectrical and hydrogeological study for the assessment of groundwater resources in Wadi Al Bih, UAE

Drilling information, historical water table levels, groundwater salinity records of the existing water wells in Wadi Al Bih area, United Arab Emirates, were stored in a geodatabase and used to characterize the geological and hydrogeological settings of this area. A 2D earth resistivity imaging survey was conducted for the first time in the Northern UAE to determine the potential of the Quaternary aquifer and its groundwater quality in the areas where there are no monitoring wells. The results of the chemical analyses of the collected groundwater samples together with the inversion results of the resistivity data were used to draw a total salinity map and determine the spatial variations in groundwater quality. The inversion results of the 2D earth resistivity imaging data indicated that the Quaternary aquifer in the study area is in a good connection with the underlying carbonate aquifer. It also indicated that the carbonate aquifer is of major regional and vertical extension and it contains the fresh water in this area. The data stored in the developed database were used to produce different types of geopotential maps.     

Study of cracks and fissures phenomenon in Central Saudi Arabia by applying geotechnical and geophysical techniques

This paper presents an approach to investigate the phenomenon of faults and cracks that appeared in the earth’s crust surface in Al-Qassim region, Saudi Arabia. Geophysical and geotechnical methods were used together in order to evaluate these cracks and identify the reasons that led to the emergence of such phenomenon. This type of faults and cracks can normally occur due to a geological or physical event or due to the nature and properties of the subsurface material. It was intended to use two different techniques at a time, compare, and integrate the outcome of the results. The geotechnical works included advancing rotary boreholes to depths of 25 to 31 m with sampling and testing. The geophysical method used included performing 2D electrical resistivity lines. The results of geophysical and geotechnical tests showed good agreement. The use of 2D electrical resistivity was found useful to establish the layer thicknesses of shale and highly plastic clay. This cannot be determined without deep and expensive direct boring investigation or other sophisticated methods. The results showed that the ground cracks and faults were mainly caused due to the nature of the soil in the area, which is considered as a high-risk soil type and classified within expansive soil groups. The subsurface formation contained excessive fines with high percentage of highly plastic clay materials. The volume changes due to humidity variations can result in either swelling or shrinking. These changes can have significant impact on engineering structures such as light buildings and roads. The possible mechanism of cracks formation is explained.     

A microseismic experiment in Abu Dhabi,United Arab Emirates: implications for carbonate reservoir monitoring

A microseismic experiment utilizing a single downhole array of eight 3-component receivers was conducted in an offshore oilfield in the emirate of Abu Dhabi in the United Arab Emirates. The Lower Cretaceous Thamama Group is the major carbonate reservoir in the field producing from six zones. Microseismic data was acquired in conjunction with gas injections that took place in the Thamama IV A and IV B reservoirs during 9 days of acquisition. The aim of the experiment was to monitor the microseismic activity arising in the carbonate reservoirs as a result of gas injection. A total of 103 microseismic events were detected from two of the receivers. For the majority of these events, there were no well-defined P wave arrivals, probably due to the presence of strong background noise and the very weak microseismic signals. The results from this experiment indicate that the detected events are probably related to the microseismic activities caused by the gas injection within the Thamama IV B reservoir. Therefore, downhole microseismic monitoring methods can potentially provide valuable information about the fracture systems within the carbonate reservoirs of Abu Dhabi's oilfields.     

Contribution of diffuse sources to the sediment and phosphorus budgets in Ben Chifley Catchment,Australia

Relative contribution of different diffuse sources to the sediment and phosphorous (P) budgets in the Ben Chifley Reservoir was estimated using a multivariate mixing model and geochemical indices and tracers. The influence of the underlying geology on land use characteristics and the dynamics of sediment and P in the catchment were discussed. Sediments currently in transport to the reservoir are derived mainly from areas underlain by Quaternary alluvium, accounting for 33% of the reservoir sediment budget. A major portion of the sediments from the Quaternary alluvium originates from pasture land which also contributes about 60% of sediment-bound P in the reservoir, followed by cropland (30%) and forest area (10%). Phosphorus-based fertiliser contributes more than 50% of the soil P in pasture and cropland and more than 60% in forest plantation area. The remaining P reaching the reservoir originates from natural soils (native sources). Phosphate from both fertiliser and native sources are transported to the water courses and ultimately the reservoir as a consequence of gully, stream bank and surface erosion. Erosion control, trapping of fertiliser runoff, establishing riparian vegetation and reducing application of P-based fertiliser by increasing native pasture cultivation in the risk areas should be considered as management options for controlling the impact of P and sediment in the reservoir.     

Active crustal shortening in NE Syria revealed by deformed terraces of the River Euphrates

The Africa–Arabia plate boundary comprises the Red Sea oceanic spreading centre and the left‐lateral Dead Sea Fault Zone (DSFZ); however, previous work has indicated kinematic inconsistency between its continental and oceanic parts. The Palmyra Fold Belt (PFB) splays ENE from the DSFZ in SW Syria and persists for ～400 km to the River Euphrates, but its significance within the regional pattern of active crustal deformation has hitherto been unclear. We report deformation of Euphrates terraces consistent with Quaternary right‐lateral transpression within the PFB, indicating anticlockwise rotation (estimated as 0.3° Ma^?1 about 36.0°N 39.8°E) of the block between the PFB and the northern DSFZ relative to the Arabian Plate interior. The northern DSFZ is shown to be kinematically consistent with the combination of Euler vectors for the PFB and the Red Sea spreading, resolving the inconsistency previously evident. The SW PFB causes a significant earthquake hazard, previously unrecognized, to the city of Damascus.     

Calibration of the Hydrological Simulation Program Fortran (HSPF) model using automatic calibration and geographical information systems

Calibrating a comprehensive, multi‐parameter conceptual hydrological model, such as the Hydrological Simulation Program Fortran model, is a major challenge. This paper describes calibration procedures for water‐quantity parameters of the HSPF version 10·11 using the automatic‐calibration parameter estimator model coupled with a geographical information system (GIS) approach for spatially averaged properties. The study area was the Grand River watershed, located in southern Ontario, Canada, between 79° 30′ and 80° 57′W longitude and 42° 51′ and 44° 31′N latitude. The drainage area is 6965 km². Calibration efforts were directed to those model parameters that produced large changes in model response during sensitivity tests run prior to undertaking calibration. A GIS was used extensively in this study. It was first used in the watershed segmentation process. During calibration, the GIS data were used to establish realistic starting values for the surface and subsurface zone parameters LZSN, UZSN, COVER, and INFILT and physically reasonable ratios of these parameters among watersheds were preserved during calibration with the ratios based on the known properties of the subwatersheds determined using GIS. This calibration procedure produced very satisfactory results; the percentage difference between the simulated and the measured yearly discharge ranged between 4 to 16%, which is classified as good to very good calibration. The average simulated daily discharge for the watershed outlet at Brantford for the years 1981–85 was 67 m³ s^?1 and the average measured discharge at Brantford was 70 m³ s^?1. The coupling of a GIS with automatice calibration produced a realistic and accurate calibration for the HSPF model with much less effort and subjectivity than would be required for unassisted calibration. Copyright © 2002 John Wiley & Sons, Ltd.     

An Interacting Model of Dark Energy in Brans-Dicke Theory

In this paper it is shown that in non-minimally coupled Brans-Dicke theory containing a self-interacting potential, a suitable conformal transformation can automatically give rise to an interaction between the normal matter and the Brans-Dicke scalar field. Considering the scalar field in the Einstein frame as the quintessence matter, it has been shown that such a non-minimal coupling between the matter and the scalar field can give rise to a late time accelerated expansion for the universe preceded by a decelerated expansion for very high values of the Brans-Dicke parameter ω. We have also studied the observational constraints on the model parameters considering the Hubble and Supernova data.     

Heavy metals removal from synthetic wastewater by a novel nano-size composite adsorbent

The effects of varying operating conditions on metals removal from aqueous solution using a novel nano-size composite adsorbent are reported in this paper. Characterization of the composite adsorbent material showed successful production of carbon nanotubes on granular activated carbon using 1 % nickel as catalyst. In the laboratory adsorption experiment, initial mixed metals concentration of 2.0 mg/L Cu²⁺, 1.5 mg/L Pb²⁺ and 0.8 mg/L Ni²⁺ were synthesized based on metals concentration from samples collected from a semiconductor industry effluent. The effects of operation conditions on metals removal using composite adsorbent were investigated. Experimental conditions resulting in optimal metals adsorption were observed at pH 5, 1 g/L dosage and 60 min contact time. It was noted that the percentage of metals removal at the equilibrium condition varied for each metal, with lead recording 99 %, copper 61 % and nickel 20 %, giving metal affinity trend of Pb²⁺ > Cu²⁺ > Ni²⁺ on the adsorbent. Langmuir’s adsorption isotherm model gave a higher R² value of 0.93, 0.89 and 0.986 for copper, nickel and lead, respectively, over that of Freundlich model during the adsorption process of the three metals in matrix solution.     

Peculiarities of the kinematics of the west scotia mid-oceanic ridge

The first map of the acoustic basement and a new map of the C⁴-C¹² chrons are made for the area of the paleospreading West Scotia Ridge. The analysis of the constructed maps and the calculations showed that the bottom growth in the ridge axes began in the southeast in the interval of chron C^12r (31.116–33.266 Ma B.P.). In the period of chron C11r (30.217–30.627 Ma), a hundred-kilometer northwestward jump of the spreading axis occurred. The maximal values of the bottom growth (about 6.3 cm/yr) were in the interval of chrons C6–C6B (18.748–22.546 Ma); then, the spreading began to fade. In the time of chron C3n.1r (3.300–4.493 Ma B.P.), the axis of the paleo-mid-oceanic ridge died. The spreading was accompanied with northeastward propagating of the axes, and the propagating proper had an impulse character.     

The separation of Ceylon from Antarctica

The geometry of the junction between Ceylon and Antarctica during the Gondwanaland breakup is still under discussion. Analysis of the available geological-geophysical materials has allowed the peculiarities of Ceylon separation from Antarctica to be characterized, the new paleogeodynamical reconstruction to be elaborated, and a prognosis of the tectonic structure and mineral resources in the areas of Antarctic coast that were adjacent to Ceylon to be made.