Arabian Journal of Geosciences

Published by Springer Verlag
Online ISSN: 1866-7538
Print ISSN: 1866-7511
The main goal of this paper is to extract land topographical information by analyzing the 3D GPR data by the Wavelet Transform Modulus Maxima Lines (WTMM) method. The first objective is to delimitate boundaries of each obstacle, the second is to characterize each one with a special roughness coefficient. Application on real data shows that the proposed tool can enhance the GPR data interpretation.
Subsurface Late Cretaceous succession has been recovered from 16/G-1, an offshore exploratory well that located in the Qamar Basin, eastern Republic of Yemen. This paper deals with the study of source rocks, maturation, hydrocarbon evaluation, and palynofacies of the Late Cretaceous Mukalla and Dabut Formations of the Mahra Group. These two formations consist of an intercalation of argillaceous, carbonates, siltstones, sandstones and coal layers. The sedimentary organic matter as amorphous organic matter, phytoclasts and palynomorphs are investigated and identified under transmitted light microscope. Spores, pollen, dinoflagellates, algae, fungi, and acritarchs in addition to foraminiferal lining test have been also identified. The optical and organic geochemical studies were used to evaluate the source rock, maturation and its hydrocarbons potentiality. The thermal alteration index, vitrinite reflectance, rock-eval pyrolysis, and palynofacies were also used. The upward increase in the relative abundance of marine versus terrestrial input reflects a major marine transgression and retregration cycles from Campanian to Maastrichtian stages. The Mukalla and Dabut Formations are late immature to mature stages with kerogen types II and III. The hydrocarbons generation potentiality of two formations is oil and wet gas prone indicators.
In this study, a digital elevation model was used for hydrological study/watershed management, topography, geology, tectonic geomorphology, and morphometric analysis. Geographical information system provides a specialized set of tools for the analysis of topography, watersheds, and drainage networks that enables to interpret the tectonic activities of an area. The drainage system maps of Zagros Mountains in southwest Iran have been produced using multi-temporal datasets between 1950 and 2001 to establish the changes between geomorphic signatures and geomorphic aspect during time and to correlate them with recent neo-tectonics. This paper discusses the role of drainage for interpreting the scenario of the tectonic processes as one of important signatures. The study shows variation in drainage network derived from topography maps. Thus, changes in drainage pattern, stream length, stream gradient, and the number of segment drainage order from 1950 to 2001 indicate that Zagros Mountain has been subjected to recent neo-tectonic processes and emphasized to be a newly active zone.
The groundwater resources of the confined aquifers north of El Obeid town in Central Sudan are inadequate and limited due to absence of recent recharge and alternative sources of induced recharge contrary to the findings of Abdalla (Abdalla 2009a, Arab J Geosci, DOI 10.1007/s12517-009-0042-4), who claimed that 35 million cubic meters/year can be continually extracted from the deep aquifers of Bara Basin to supply El Obeid city without endangering the groundwater resources in the region.
This is a conducted study of the physicochemical and the bacteriological characteristics of groundwater from 24 wells in the six departments of Algeria: Mostaganem, Mecheria, Naama, Tiaret, Bechar, and Adrar. The six departments and surrounding areas depend heavily on water from wells as a resource for drinking water, as well as domestic, industrial, and agricultural uses. Understanding the groundwater chemistry provides insight into the interactions of water with the environment and contributes to better resource management. In total, 24 water samples from wells have been analyzed for major physical–chemical elements and metals. The results show that the water have pH values ranging between 7.1 and 8.2, salinity between 213 and 1,273mg/L, and nitrate concentrations between 30 and 48.7mg/L. The high concentration of nitrates is explained by the utilization of chemical fertilizers in agriculture. Almost all the samples are of type Na–SO4 and Na–HCO3, and the trace metal concentrations are within the admissible standard ranges. The bacteriological analysis of 24 samples analyzed showed that nine samples (nos. 3, 5, 8, 12, 14, 16, 17, 22, and 23) are contaminated. We conclude that the groundwater samples may safely be used for drinking, domestic, agricultural, and industrial purposes with the exception of the following samples: nos. 3, 5, 8, 12, 14, 16, 17, 22, and 23. KeywordsGroundwater–Western and Southern Algeria–Physical–chemical elements–Bacteriological analysis
The goal of this research is to examine one-dimensional total electron content (TEC) data using principal component analysis (PCA) to search for total electron content (TEC) anomalies associated with large earthquakes in 24 h prior to nucleation. The characteristics of principal eigenvalues generated for TEC prior to 24 earthquakes of magnitude scale M ≥ 5.0 and 6 lesser earthquakes of magnitude scale M 2006) that sparse earthquake-associated TEC anomalies existed in 5 days prior to the 12 large earthquakes they examined (Lin, Terr Atm Ocean Sci, 2010). In this paper, I wish to examine the subtlety of principal component analysis in detecting earthquake-associated TEC anomalies by examining if such precursors can be detected in 24 h prior to large earthquakes. Of the earthquakes examined, TEC anomalies given by clear extreme principal eigenvalues were evident within 24 h of nucleation for 21 of the 24 earthquakes of M ≥ 5.0. After making allowance for the general status of background TEC, it is clear that these extreme principal eigenvalues are representative of earthquake-associated anomalies. For the smaller earthquakes (M
Sinkhole collapse is one of the main limitations on the development of karst areas, especially where bedrock is covered by unconsolidated material. Studies of sinkhole formation have shown that sinkholes are likely to develop in cutter (enlarged joint) zones as a result of subterranean erosion by flowing groundwater. Electrical resistivity imaging or tomography (RESTOM) is well suited to mapping sinkholes because of the ability of the technique for detecting resistive features and discriminating subtle resistivity variations. Two-dimensional electrical resistivity tomography surveys were conducted at two sinkhole sites near Cheria city where limestone is covered by about 10m of clayey soils. A Wenner transect was conducted between the two sinkholes. The electrode spacing was 2m. The length of transect is about 80m. The survey results suggest that RESTOM is an ideal geophysical tool to aid in the detection and monitoring of sinkholes and other subsurface cavities. الانهيارات الناتجة عن الفجوات الصخرية هي واحدة من أهم العوامل المؤثرة في تنمية المناطق الكارستية ، وخصوصا عندما يكون الأساس الصخري مغطى بتربة غير معززة. أظهرت الدراسات لتشكيل مثل هده الانهيارات أنه من المرجح أن تتطور في شكل القاطع نتيجة لتآكلت ناتجة عن تدفق المياه الجوفية. تعتبر المقاومية الكهربائية أو التصوير المقطعي (RESTOM) مناسبة تماما لرسم الخرائط الصخرية بسبب قدرة هده التقنية للكشف عن ميزات المقاومية و اختلافات المقاومية الخفية. أجريت عملية المسح المقطعي بطريقة المقاومية الكهربائية ثنائية الأبعاد في موقعين بالقرب من مدينة الشريعة حيث أن الطبقات الجيولوجية والمكونة أساسا من الحجر الجيري مغطاة بحوالي 10 أمتار من التربة الطينية. أجري مقطع جيوفيزيائى بطريقة Wenner بين اثنين من الفجوات الصخرية حيث كان التباعد بين كل قطب 2م و طول المقطع حوالي 80 متر. وتشير نتائج دراسات المسح عن طريق التصوير المقطعي RESTOM أنها أداة جيوفيزيائية مثالية للمساعدة في كشف ورصد الفجوات الصخرية وغيرها من التجاويف تحت سطح الأرض. KeywordsResistivity tomography–RESTOM–Karst–Sinkhole–Cheria–Algeria
Applying the iterative shooting/bisection technique for rapid forward modeling to the seismic explosion data, we could refine the crustal velocity structure model of the western part of the Hidaka collision zone, Hokkaido, Japan. We used only the precise P-wave first arrival data obtained by the Research Group for Explosion Seismology, which set up a 113.4-km-long profile in August 2000 along with 327 observation points and four shot points with TNT charges from 100 to 300kg. We could estimate a two-dimensional inhomogeneous crustal velocity structure model with a velocity decrease in the eastern direction at a depth of 15.7km, several portions of velocity reversals with depth and a low velocity anomaly proposed in previous studies. The root-mean-square of travel-time residuals was improved from 0.398s for the previous structure model to 0.176s for the present model with a reduction of 55.8%. تم إستخدام طريقة الإطلاق والتجزيئ للنمذجه المستعجله في تحليل بيانات الرصد الإهتزازي لتعقب التغير في دراسة التركيب القشري للجزء الغربي من نطاق هيداكا التصادمي في هوكايدو، اليابان.قام الباحثان بإستخدام البيانات التي جمعت بواسطة مجموعة الرصد الإهتزازي البحثية التي شملت تسجيلات 327 راصد لأربعة تفجيرات بإستخدام 100 إلى 300 كغم من مادة التي إن تي ، حيث تم التسجيل على طول 113.4 كم في شهر أغسطس من عام 2000 الميلادي.تمكنا من تقدير سرعة الموجات في التركيب القشري الثنائي الأبعاد، وظهر إنخفاض في السرعة ناحية الجهة الشرقية من منطقة البحث عند عمق 15.7كم مصحوبه بعدد من الإنقلابات في قيم السرعه مع تغير العمق وكذلك وجود إنخفاض شاذ للسرعه في المنطقة مدعم بنتائج أبحاث سابقة.أعطت النتائج قيمة جذر متوسط المربعات مساويه لـ 0.176 ثانية في الفرق بين زمني الإنتقال المحسوب والذي تم رصده ، بإنخفاض قدره 55.8 بالمائة عن ذلك المسجل بإستخدام نتائج التركيب القشري السابقه والتي بلغت 0.398 ثانيه.
The Masila area is located in the Hadhramaut region in east central Yemen. Oil was first discovered in the area in late 1990 with commerciality being declared in late 1991. Oil production began in July 1993. By the end of December 1999, the daily production rate was set at 210,000 stock tank barrels/day (STB/D) of very low gas-oil ratio (GOR) oil under partial to full water drive. About 90% of the reserves are found in the Lower Qishn Clastics Member of the Qishn Formation. This paper focuses on the detailed 3D geological modeling of the Lower Cretaceous Sequence conducted through an integrated study. There are three critical areas in the process of modeling reservoirs that involve geological and geophysical modeling, reservoir characterization, and reservoir flow modeling. This paper presents methodologies found useful during the modeling of these reservoirs including field case histories for the Lower Cretaceous reservoir in the Masila oilfield.
Abstract Conceptual geological repositories are generally used for disposing spent nuclear wastes containing both high and low level of nuclear radiation and heat. Due to its long-lasting effect, it is imperative to analyze its long-term effect on the surrounding rock. Before analyzing radiation and thermal effect, it is important to have structurally stable cavern because designing an opening in rock is a more difficult problem than designing the structure made of steel. Underground rocks are under stress because of the weight of the overlying rock, and in addition, an underground opening will produce a stress concentration and stress relaxation in the surrounding rock. If the induced stress in the surrounding rock exceeds its strength, the opening will fail either by fracturing or by deforming more than the tolerable limit. In this paper, the stability of four different shapes of excavation has been examined for conceptual geological repositories in Indian context. This has been done using equivalent continuum numerical model which has been incorporated in the commercial finite difference code-FLAC-3D. Effects of opening shapes on stress distribution, subsidence of crown and side wall, and their stability have been analyzed and discussed. The validation of FLAC3D software for its applicability in conceptual underground geological repositories has been done with a published literature.
For the first time, the calcareous nannofossils of the chalky limestone of upper Abderaz Formation and lower part of Abtalkh Formation have been studied. In this study, 83 nannoplanktonic species of 45 genera were identified and presented. A biostratigraphic study of calcareous nannofossils from this section has allowed the recognition of five calcareous nannofossil biozones of Sissingh (Geol Mijnbouw 56:37–65, 1977) CC17–CC21. On the obtained calcareous nannofossils, the age of this section is Late Santonian/Early Campanian–Early Late Campanian. تمت دراسة الأحافير الكلسية الدقيقة من الحجر الطباشيري لمتكون الأبدراز Abderaz العلوي والجزء السفلي لمتكون الأبتالخ Abtalkh لأول مرة. في هذه الدراسة تم التعرف على 83 نوع من الكائنات الطافية الدقيقة منتمية إلى 45 جنس. أتاحت الدراسة البيوستراتجرافية لتحديد خمس نطق حيوية للأحافير الكلسية الدقيقة والمعرفة من قبل الباحث (Sissingh, 1977) والمسلسلة بأرقام CC17 – CC21. توصلت هذه الدراسة إلى تحديد عمر القطاع المدروس والذي يتراوح زمنه بين السانتوني المتأخر Late Santonian والكمباني مبكر Early Campanian إلى الجزء المبكر من الكمباني المتأخر Early Late Campanian. KeywordsCalcareous nannofossil–Santonian–Campanian–Chalky limestone–Abderaz–Abtalkh
a Distribution of equilibrium partial pressure of CO 2 (on log scale) as computed with WATEQC. b Plots of saturation indices with respect to some siliceous and carbonate minerals, are computed with
Recalculated water analyses showing the extent of reactions (in mmol/L) and mean parameter values for the groundwater groups used in the inverse modeling calculations
Summary of mass transfer for selected geochemical models
In this work, we present results of the hydrogeochemical and isotopic studies on groundwater samples from the El Ma El Abiod Sandstone aquifer, in Tébessa, Algeria. Chemical and environmental isotope data are presented and discussed in order to identify the geochemical processes and their relation with groundwater quality as well as to get an insight into the hydrochemical evaluation, in space and time, of groundwater and of the origin of dissolved species. A combined hydrogeologic and isotopic investigation have been carried out using chemical and isotopic data to deduce a hydrochemical evaluation of the aquifer system based on the ionic constituents, water types, hydrochemical facies, and factors controlling groundwater quality. All of the investigated groundwaters are categorized into two chemical types: low mineralized water type and relatively high mineralized water type. Interpretation of chemical data, based on thermodynamic calculations and geochemical reaction models of selected water groups constructed using PHREEQC, suggest that the chemical evolution of groundwater is primarily controlled by water-rock interactions, involving (1) acidic weathering of aluminosilicates, (2) dissolution of secondary carbonate minerals, and (3) cation exchange of Na+ for Ca2+. However, the original composition of groundwater may have been modified by further secondary processes such as mixing of chemically different water masses. The combined use of SI and mass-balance modeling has shown to be a useful approach in interpreting groundwater hydrochemistry in an area where large uncertainties exist in the understanding of the groundwater flow system. Interpretation of 18O and 2H, suggest that the recharge of the investigated groundwaters may result from different mechanisms.
Statistical indices of the simplified parameters 
The Penman–Monteith (PM) method is the most recommended method for estimating reference evapotranspiration (ETo). The PM equation requires several parameters to be available, either measured or computed. Some of these parameters are conventionally calculated by some slightly sophisticated formulas, especially for handy calculations. This paper aimed to derive some simpler statistical equivalents to these formulas. Simplifications were performed to the formulas of the saturation vapor pressure e o[T], slope of vapor pressure (∆), atmospheric pressure (P), the psychrometric constant (γ), wind speed correction, the long-wave radiation, R nl; the sunset hour angle, ω s; and the extraterrestrial radiation, R a. For the first five parameters, the parameter-independent factor was analyzed for its extremes, then fitted by interpolation to a simpler equivalent formula. The last three parameters were fitted to simpler form through data from the FAO-CLIMWAT database. Each of the simplified formulas was compared to the conventional one; some correlation indices were applied to validate the new formulas. The ETo was calculated for all stations in the CLIMWAT database by both simplified and conventional formulas. All the correlation results were excellent, with a minimum correlation coefficient of 0.9966. The simplified formulas were proven to be equivalent in performance, with almost no loss in accuracy but simpler in form and faster in execution in the online database applications.
The present study assesses groundwater resources in the semiarid central Sudan, where 20 deep productive wells were installed to supply a major city in the region, El Obeid. The wells, which has an average 20 L/s discharge each, are taping a deep semiconfined to confined aquifer of fluvial silisiclastics deposited in the Tertiary-Pleistocene. Groundwater modeling was used as a technique to interpret the hydrologic system in arid to semiarid central Sudan and to simulate the future influence of the project on the hydrogeologic system. The simulation confirmed that steady-state flow conditions have been currently reached as indicated by consistency of computed heads. It also calibrated the values of the conductivity and recharge and ensured the sustainability of the El Obeid water supply project. A total of 3.5×107m3/year can be continually extracted from the deep aquifer to supply El Obeid city without endangering the groundwater resources in the region. The decline in water level will not exceed 25 m during the first 10 years, while indefinite continuous pumping will affect only the vicinity of the wells in a circle of 30 km diameter. Therefore, aquifer storage capacity and hydraulic properties encourage further groundwater exploitation. The present use of groundwater is extremely lower than the present demand, and it can potentially cover future demands without introducing significant changes to the system. The increase of pumping cost due to the decline in head subsequent to project operation was found to be minimal and of local effect.
Geologic sketch map of the Abu-Diab area (after ElRamly 1972)
Microthermometric results of fluid inclusions in quartz from Abu-Diab granite
a Chemical composition of the Abu-Diab granite plotted on TAS classification diagram of Le Maitre et al. (1989). b K 2 O vs. SiO 2 diagram after Rickwood (1989). c The Shand's Index diagram (A/NK vs. A/CNK). d Agapitic Index (AI) vs. SiO 2 diagram (Liègeois and Black 1987); the oval area shows post-collision granite (PCG)
The Neoproterozoic granite of Gabal Abu Diab, central Eastern Desert of Egypt, comprises mainly garnetbearing granite and alkali feldspar granite intruded into calc-alkaline granodiorite-tonalite and metagabbro-diorite complexes. The garnet-bearing granite is composed mainly of plagioclase, K-feldspar, quartz, garnet and primary muscovite ± biotite. The presence of garnet and primary muscovite of Abu-Diab granite suggests its highly fractionated character. Geochemically, the garnetbearing granite is highly fractionated as indicated from the high contents of SiO2 (74.85-77.5%), alkalis (8.27 to 9.2%, Na2O+K2O) and the trace elements association: Ga, Zn, Zr, Nb and Y. This granite is depleted in CaO, MgO, P2O5, Sr and Ba. The alumina saturation (Shand Index, molar ratio A/CNK) of 1.0 to 1.1 indicates the weak peraluminous nature of this garnet-bearing granite. The geochemical characteristics of the Abu Diab garnetbearing granite are consistent with either the average I-type or A-type granite and also suggest post-orogenic or anorogenic setting. A fluid inclusions study reveals the presence of three fluid generations trapped into the studied granite. The earlier is a complex CO2-H2O fluid trapped in primary fluid inclusions with CO2 contents > 60 vol.%. These inclusions were probably trapped at minimum temperature > 400°C and minimum pressure > 2 kb. The second is immiscible water-CO2 fluid trapped in secondary and/or pseudo-secondary inclusions. The trapping conditions were estimated at temperature between 400°C and 170°C and pressure between 900 and 2000 bar. The latest fluid is low-salinity aqueous fluid trapped in secondary two-phase and mono-phase inclusions. The trapping conditions were estimated at temperature between 90°C and 160°C and pressure < 900 bar. The origin of the early fluid generation is magmatic fluid while the second and third fluids are of hydrothermal and meteoric origin, respectively.
Jordan, located at the western edge of the Arabian Plate, stands out from the remaining part of the Arabian Peninsula by its abundance in radioactive elements, mainly uranium, in a way so far not found elsewhere on the Arabian Peninsula. Uranium (U) and thorium in Jordan are concentrated in eight different types of ore mineralization: (1) intrusive-related (intramagmatic), (2) vein-type, (3) superficial, (4) sandstone-hosted (5) limestone-hosted, (6) U-Th-REE placer-type, (7) black shales, and (8) phosphorites. The major concentration of radioactive elements are synsedimentary and diagenetic in nature, mainly in near-shore marine depositional environments where uranium contents are abnormally high in the late Cretaceous to Paleogene phosphorites and increasing towards the mobile shelf of the Tethys ocean. These uraniferous phosphorites form the source of uranium that was redeposited within terrigenous chemical residues of lacustrine-fluvial depositional systems in Central Jordan (calcretes). Faultbound radiometric anomalies are caused by hot brines being vented along with the Jordan-Dead-Sea rifting. Presumably, low-grade U accumulation in (hot) black shales and marls of Silurian age are responsible for these radiometric anomalies. In the present paper, the Jordanian uranium concentrations are compared with reference types of uranium deposits elsewhere in the world to get an idea if the geological, chemical, and mineralogical features of analogue uranium mineralization in Jordan are indicative of economic targets. The uranium concentration in Jordanian phosphorites has been tracked beyond the border into Syria, Iraq, Israel, and Saudi Arabia. The uranium potential in neighboring countries is assessed based on the current geological data available for the Mediterranean Phosphorite Belt which is poised to become a another string to the bow with respect to energy supply on the Arabian Peninsula.
Palynological and organic geochemical analysis are performed in this study for 220 samples of cores and cuttings collected from the Ordovician Khabour, Silurian Akkas, and Upper Devonian Kaista Formations in wells Akkas/1-6, Khleisya/1, KH5/6, and KH5/1 of West Iraq. Their diagnostic organic matters are abundant acritarchs (134 species belonging to 54 genera, including marine algae of Tasmanites, Deflandstrum, and brazinophytes) and a few spores (21 species belonging to 16 genera) and Chitinozoa (43 species belonging to 12 genera) as well as scolecodonts, graptolite siculae, cuticles, and amorphous organic matters. On the basis of acritarchs with tentative selections of Chitinozoa and spores, this succession is subdivided into ten palynozones (PZ1–PZ10) within a stratigraphic framework and correlated with equivalent strata in Saudi Arabia and Libya. Beds of the Khabour and lower part of Akkas Formations were deposited in anoxic–dysoxic marine shelf environments northern Gondwana Continent with provincial acritarchs. These deposits were extending from outer to inner neritic with affects of local upwelling currents and lagoons, especially in boreholes Akkas/1, KH5/1, and KH5/6. Hydrocarbon generations potential are assessed by plotting organic matter types in palynofacies context of Bujaks (1970) graphical model with depths along with log of thermal maturation indices on the basis of the color changes of the acritarchs Diexallophasis denticulata–Orthosphaeridium ternatus and Baltisphaeridium constrictum as well as kerogen types and total organic carbon (TOC). These organic matters are up to 16% TOC, especially for the hot shale of the Lower Silurian Akkaz Formation, very low asphalting and sulfur, saturated and aromatic hydrocarbons of more than 96%, and high peaks of C2–C20 gas chromatography that could indicate predominant gas generation with some light oils. The associated gases are mainly methane and ethane of CH4, C2H6, and C3H8. Accordingly, source potential for wet gas and condensates could be assessed for depth of 2,750–3,000m and dry gas for depth of 3,570–3,650m in well Akkas-1 only from the Ordovician Kabour Formation. Little oil might be generated from the lower Silurian Akkas formation in borehole Akkas-1 and KH5/6. These potential source rocks are extended toward Jordon, southwest Iraqi Desert and Syria. Accumulation sites of these generated gas and little oil could be within the sandstone porosities of 10–17% and permeability of 500mD sealed by the non permeable shale's along closures of the structured anticline fold and fault of this field as well as along the unconformity boundary of the Upper Silurian Akkas Formation with the Upper Devonian Kaista Formation. Accordingly, Lower Paleozoic total petroleum system of generation, migration, and accumulations could be assessed for a basin includes West Iraq and their extensions in Jordon and Syria. لقد تم في هذه الدراسة اجراء تحليلات بالينولوجية وجيوكيمائية عضوية لمائة وعشرين انموذج فتاتات ولبابات صخرية تم جمعها من تكاوين الخابور الاوردوفيشي وعكاز السيلوري وكيستا الديفوني الاعلى في آبار النفط عكاز 1-6 وخليصيه-1 وآبار المياه KH5/6 وKH 5/1. تتصف موادها العضوية الرسوبية بهيمنه الاكريتارك (134 نوع تعود الى 54 جنس بضمنها الطحالب البحرية) وقليل من الابواغ (21 نوع تعود الى 16 جنس) وكايتينات (43 نوع تعود الى 12 جنس) علاوة على السكوليكودونت وسيكيولا الكرابتولايت والكيوتكل ومواد عضوية عديمه الشكل التركيبي. اعتماد على الاكريتارك وانواع مختارة من الكايتينات والابواغ، فقد تم تقسيم هذا التتابع الطبقي الى عشرة انطقة بالينولوجية (PZ1 وحتى PZ10) ضمن هيكل طباقي امكن مقارنة طبقاته مع المملكة العربية السعودية وليبيا. لقد تم ترسيب طبقات تكوين الخابور والجزء الاسفل من تكوين عكاز في بيئات مختزله ضمن الرف القاري البحري شمال قارة الكوندوانا مع كونها تحتوي على تعايش عالمي اقليمي للاكريتارك. ان تلك الترسبات امتدت بين البيئتين البحريتين النرتيه الداخلية والنرتيه الخارجية مع تأثير التيارات البحرية الصاعدة واللاغون، بالاخص في الابار عكاز-1، KH5/1 ، KH5/6. لقد تم تقويم نشوء الهيدروكاربونات في هذه الدراسة بواسطة تسقيط انواع المواد العضوية في مرتسم موديل السحنات البالينولوجية المقترح من بوجاك (1970) مع العمق اضافة الى معامل التغير الحراري (TAI) اعتماداً على التغير اللوني للاكريتاك وانواع الكيروجين والكاربون العضوي الاجمالي (TOC). ان اجمالي هذه المواد العضوية يصل الى 16% وزناً وبالاخص لصخور سجيل السيلوري الاسفل من تكوين عكاز ونسبة قليلة جداً من الاسفلت والكبريت وهيدروكاربونات مشبعة واروماتية لاكثر من 96% وقمم عالية للكاربون (20-2) في جهاز الغاز كروماتوكرافيا الذي يشير الى أغلبية نشوء للغاز مع بعض النفط. ان الغازات المرافقة هي بكتيريا الميثان والايثان (CH4, C2H6, C3H6). لذلك يمكن تقويم هذه الصخور على انها مصدرية واعدة للغاز والمكثفات للاعماق 2750-3000 متر وغاز جاف للعمق 3570-3650 متر في بئر عكاز-1 من تكوين الخابور الاوردوفيشي فقط وان قليل من النفط ربما قد نشأ من السيلوري الاسفل لتكوين عكاز في البئرين عكاز-1 و KH5/6. ان هذه الصخور المصدرية الواعدة يمتد اقليمياً بأتجاه الاردن وجنوب غرب العراق باتجاه السعودية وباتجاه سوريا. ان مناطق تجميع هذه الغازات والنفط الناشئون يمكن ان يكون طبقات الصخور الرملية ذات المسامية 10-17% والنفاذية 500 ميللي دراسي لتكويني الخابور و عكاز ومحكمة من الاعلى بالصخور السجيلية غير النافذة في منغلقات تركيبية من الطيات والفوالق اضافة الى سطح عدم لاتوافق بين تكوين عكاز السيلوري وتكوين كيستا الديفوني الاعلى. لذلك فان نظام نفطي اجمالي في حقب الحياة القديمة الاسفل يشمل النشوء والهجرة والتجميع يمكن تحديده في هذا الحوض الذي يشمل غرب العراق وامتداداته في سوريا والاردن والسعودية. KeywordsPalynostratigraphy-Hydrocarbon generation-Accumulations-Lower Palaeozoic-West Iraq
The final ratio equation of an isotopic element in a rock, derived from water/rock formula of McCulloch et al. Earth Planet Sci Lett 46:201-211, 1980, McCulloch et al. J Geophys Res 86:B4 2721-2735, 1981 is used to assess the behavior of diverse suites of rocks towards the alteration effect, and what implications can give about hydrothermal alteration in terms of isotopic compositions. Due to their higher Sr and lower Nd initial ratios than seawater, rocks of metamorphic and sedimentary signatures such as carbonates and Precambrian basement rocks show similar but inverse mixing curves compared with igneous rocks. Sr composition of rocks immediately alters by seawater, while Nd composition keeps unchanged until large volumes of water are added. Although, this can be attributed to the very low Nd concentration in seawater, it indicates that Nd-exchange may only take place under seawater, possibly hydrothermally by circulated seawater, and Nd-concentration of less altered crustal rocks are apparently primary. The isotopic composition and rock mineralogy seem to be the main factors controlling the volume of water required to cause isotopic alteration in rocks. Crustal rocks require higher water volumes due to their relatively low temperature minerals, whereas, mantle peridotites mainly consist of residual olivine minerals that are highly susceptible to alteration and lack of Sr and Nd compositions, and so need less amount of water for metasomatism. This property reduces the limited penetration effect as the mafic affinity increases at depth in the oceanic crust, and enables modified (probably acidified) circulated fluids to maintain ion exchanging and leaching throughout their passageway.
The Sahara–Umm Adawi pluton is a Late Neoproterozoic postcollisional A-type granitoid pluton in Sinai segment of the Arabian–Nubian Shield that was emplaced within voluminous calc-alkaline I-type granite host rocks during the waning stages of the Pan-African orogeny and termination of a tectonomagmatic compressive cycle. The western part of the pluton is downthrown by clysmic faults and buried beneath the Suez rift valley sedimentary fill, while the exposed part is dissected by later Tertiary basaltic dykes and crosscut along with its host rocks by a series of NNE-trending faults. This A-type granite pluton is made up wholly of hypersolvus alkali feldspar granite and is composed of perthite, quartz, alkali amphibole, plagioclase, Fe-rich red biotite, accessory zircon, apatite, and allanite. The pluton rocks are highly evolved ferroan, alkaline, and peralkaline to mildly peraluminous A-type granites, displaying the typical geochemical characteristics of A-type granites with high SiO2, Na2O + K2O, FeO*/MgO, Ga/Al, Zr, Nb, Ga, Y, Ce, and rare earth elements (REE) and low CaO, MgO, Ba, and Sr. Their trace and REE characteristics along with the use of various discrimination schemes revealed their correspondence to magmas derived from crustal sources that has gone through a continent–continent collision (postorogenic or postcollisional), with minor contribution from mantle source similar to ocean island basalt. The assumption of crustal source derivation and postcollisional setting is substantiated by highly evolved nature of this pluton and the absence of any syenitic or more primitive coeval mafic rocks in association with it. The slight mantle signature in the source material of these A-type granites is owed to the juvenile Pan-African Arabian–Nubian Shield (ANS) crust (I-type calc-alkaline) which was acted as a source by partial melting of its rocks and which itself of presumably large mantle source. The extremely high Rb/Sr ratios combined with the obvious Sr, Ba, P, Ti, and Eu depletions clearly indicate that these A-type granites were highly evolved and require advanced fractional crystallization in upper crustal conditions. Crystallization temperature values inferred average around 929°C which is in consistency with the presumably high temperatures of A-type magmas, whereas the estimated depth of emplacement ranges between 20 and 30km (upper-middle crustal levels within the 40km relatively thick ANS crust). The geochronologically preceding Pan-African calc-alkaline I-type continental arc granitoids (the Egyptian old and younger granites) associated with these rocks are thought to be the crustal source of f this A-type granite pluton and others in the Arabian–Nubian Shield by partial melting caused by crustal thickening due to continental collision at termination of the compressive orogeny in the Arabian–Nubian Shield. يعتبر المتداخل الجوفي صحرا- أم عدوي متداخل جرانيتي من نوع A-type مابعد تصادمي في سيناء كجزء من الدرع العربي النوبي و قد تم تموضعة ضمن صخور مضيفة جرانيتية كلس- قلوية من نوع I-type خلال المراحل الختامية للحمى الأفريقي ونهاية دورة تكتونية-صهارية تضاغطية. الجزء الغربي لهذا المتداخل الجرانيتي مدفون أسفل الغطاء الرسوبي لأخدود السويس كرمية سفلية للفوالق القلزمية, بنما تقطع الجزء المنكشف منة قواطع بازلتية من العصر الثلاثي ومجموعات فوالق ذات أتجاة شمال-شمال شرق. يتكون هذا المتداخل الجوفي الجرانيتي من نوع A-type كلية من جرانيت الفلسبار القلوي ذو النسيج الفوق ذوباني ويتركب من معادن البيرثيت و الكوارتز و الأمفيبول القلوي و البيوتيت الغني بالحديد وكذلك معادن اضافية من الزيركون و الأباتيت و الألانيت. جيوكيميائيا: صخورهذا المتداخل الجوفي هي جرانيتات (A-type)عالية التمايز و حديدية وقلوية و شحيحة الى لطيفة التشبع الألومنيومي. تظهر هذة الجرانيتات الخصائص الجيوكيميائية القياسية لصخور جرانيت (A-type) من محتويات عالية من السليكا و مجموع القلويات و الزركونيوم والنيوبيوم والجاليوم و الأيتريوم و السيريوم والعناصر الأرضية النادرة وكذلك نسب الحديد/المغنسيوم و الجاليوم/ألومنيوم وعلى النقيض انخفاض الجير والمغنسيا والباريوم والسترانشيوم. أظهرت خصائص عناصر النذرة والعناصر ألأرضية النادرة بالأضافة الى العديد من طرق التمييز النشأوي ارتباطهم بصهارات مشتقة من مصادر قشرية ناشئة من خلال تصادم قارتين (بعد تصادمية) مع اضافات طفيفة من مصادر وشاحية شبيه ببازالت جزر المحيط.. فرضية الأشتقاق من مصدر قشري والبئة التكتونية بعد التصادمية َتدعم بطييعة التمايز العالي لصخور هذا المتداخل الجوفي وغياب مصحابة صخور السيانيت أوصخور مافية أولية متزامنة النشأة .تعزى البصمة البسيطة لمصادر وشاحية في هذة الصخور الى طبيعة صخور المصدر المفترضة وهى قشرة الدرع العربي النوبي (كلس قلوية من نوع I-type ) بالأنصهار الجزئي لصخوره والتي هي في الأصل ذات منشاء وشاحي شبة مؤكد. نسب الربيدوم/باريوم المفرطة الأرتفاع بالأضافة الى الأنخفاض الملحوظ لعناصر الأسترانشيوم و الباريوم و الفسفور والتيتانيوم والأيوربيوم تدل بجلاء أن هذة الجرانيتات وشديد تمايزها يتطلب تبلور تجزيئي متقدم في مستويات قشرية علوية. قيم درجات الحرارة الستنبطة والتي في حدود 929 درجة مئوية تتوافق مع دراجات الحرارة العالية المفترضة في الصهارات من نوع (A-type). يعتقد أن جرانيتات الأقواس القارية الكلس-قلوية من نوع (I-type) الأقدم عمرا والمعروفة بالجراينتات المصرية القديمة والأحدث والمصاحبة لهذة الصخور هي المصدر القشري لهذا المتداخل الجوفي الجرانيتي من نوع( A-type) وأخرون في الدرع العربي النوبي بأنصهارها الجزئي الناشئ عن زيادة سمك القشرة بسبب الأصطدام القاري الحادث قرب نهاية الحركات التكتونية التضاغطية في الدرع العربي النوبي.
Aeromagnetic data covering an area of about 40,000km2 at the west central Arabian Shield, Saudi Arabia has been collected and interpreted to provide structural map of the area. A number of normalized derivatives were used to help interpret the signature of magnetic data so that weak and small amplitude anomalies can be amplified relative to the stronger and larger amplitude anomalies. The interpretations obtained from these geophysical techniques of the field data demonstrated a strong correlation between magnetic anomalies and mapped subsurface geology. Based upon the variation in magnetic lineaments, shape amplitude, and trend structural map of the west central Arabian Shield on Saudi Arabia were obtained.
The aeromagnetic survey was conducted by the French organization, BRGM in 1966, where As-Safra prospect area at the east of Al-Madinah city was included. The aeromagnetic data were then interpreted for potential occurrences of mineralization zones along with their extensions. Spectral analysis, using Filon Fourier transform, was implemented to extract the residual anomalies that can be attributed to mineralization zones. In this study, analytic signal, normalized standard deviation (NSTD), and 3D Euler deconvolution filters were used to enhance the demonstration of subsurface mineralized zones occurrences. Analytic signal and NSTD filters showed that the studied area is dominated by three main trends controlling the occurrences of mineralized zones, NNW-SSE, N-S, and E-W to ENE-WSW. On the other hand, 3D Euler deconvolution filter showed that the dominant structures are mostly the magnetic contacts, and their depths vary between 118 and 355 m.
The monthly geochemical study of Bizerte lagoon principal affluent water consists in characterizing the water geochemical facies and their inorganic pollution degree by nutrients. The major elements analysis shows calcium sulfate to chloride calcium balanced facies. The geochemical analysis of water nutritive salts shows generally a good to excellent quality. Wadi Guenniche is considered more polluted as we recorded the highest nutrients contents. The principal component analysis of the connections between the physicochemical and geochemical parameters of Bizerte lagoon affluent water show that the low salinities, the turbidity, and the low contents of major sodium, chloride ions, and nutritive elements are the major factors of the environment controlling the good quality of this fresh water. تتمثل الدراسة الجيوكميائية الشهرية لمياه الأودية الرئيسية المتصلة ببحيرة بنزرت (شمال تونس) في تحديد التركيبة الجيوكميائية لهذه المياه و درجة تلوثها بالمواد الغير العضوية من مكونات ازوتية و فسفاطية. يبين تحليل العناصر الرئيسية تركيبة متوازنة من كبريتات الكلسيوم و كلوريد الكلسيوم. كما يظهر التحليل الجيوكميائي للأملاح الغذائية لهذه المياه عموما نوعية جيدة إلى ممتازة. تعتبر مياه وادي "قنيش" الأكثر تلوثا، حيث تم تسجيل أعلى النسب من العناصر الازوتية و الفسفاطية. يبين تحليل العناصر الرئيسية للروابط بين المعايير الفيزيوكيميائية و الجيوكميائية لمياه الأودية الرئيسية المتصلة ببحيرة بنزرت أن الملوحة المنخفضة و درجة تعكر المياه إظافة إلى النسب المنخفضة من العناصر الرئيسية (صوديوم و كلوريد) و الغذائية (ازوتية و فسفاطية)، هي العوامل البيئية الأساسية المحددة للنوعية الممتازة لهذه المياه العذبة. الكلمات المفاتيح : بحيرة بنزرت، الأودية، نوعية المياه، تحليل العناصر الرئيسية، تونس. KeywordsBizerte lagoon–Affluent–Water quality–Principal component analysis–Tunisia
Fawakhir serpentinites are the most western ophiolitic ultramafics relative to the Pan-African collision suture at the Qift-Quseir road in the Central Eastern Desert of Egypt. Their location is the basis for their selection in examining the possible contribution of the westerly dipping subducted oceanic slab-related melt/fluid with the intraplate granitic intrusion-related melt/fluid in the metasomatism of the Neoproterozoic ophiolitic serpentinites in the Eastern Desert. Non-residual mineralogy and geochemistry of serpentinites (SF1) far from the post-collision A2-type Fawakhir granitoids and those of serpentinites (SF2) in the vicinity of the granitoid pluton were investigated. The Fawakhir serpentinites are harzburgitic in composition and the Cr# (0.66–0.80) and Mg# (0.32–0.50) of their unaltered spinel cores are indicators for their forearc setting, where they were formed in the oceanic mantle wedge. Based on the spinel Cr# and the whole rock Yb–V bivariate, the melt extraction from the primitive mantle is in excess of 18% up to 24%. The HREE pattern of the SF1 serpentinites refers to the fractional type of melting. The formation of non-residual mineral phases particularly in SF2 samples (amphibole, biotite, apatite thorite, and monazite) and the enrichment of all serpentinites in trace incompatible elements refer to these two serpentinite groups having underwent modal metasomatism. It is suggested that viscous fluid/melt related to the Fawakhir granitoid emplacement metasomatized the SF2 serpentinites, causing a strong enrichment in LREE (display concave LREE; LaN/SmN = 3.32–6.25 and U-type HREE; GdN/YbN = 1.14–2.69) and a slight enrichment in Zr (12–16.62ppm). All serpentinites are enriched in fluid-mobile elements by aqueous fluids, but the SF2 are more enriched in these elements. The spiked B compared to the other fluid-mobile elements (16.97–24.61 and 42.94–60.66 × PM in SF1 and SF2 samples, respectively) suggests that these elements were added to the obducted ophiolitic Fawakhir serpentinites by the percolation of subduction-related fluids at shallow depths. The contribution of B from shallow continental crust-related fluids is debated. Hosting the Fawakhir serpentinites for the gold deposit at Fawakhir Mine implies a possible genetic relation between gold mineralizations hosted in the ultramafic rocks of the ANS and the processes of recycling of the subducted oceanic slab and the interaction with the mantle. Detailed stable and radiogenic isotopic analyses of the mineralization zones are required to address this question. KeywordsGeochemistry–Mineralogy–Fawakhir ophiolitic serpentinites–Pan-African orogeny–Intraplate and subduction-related fluids/melts–Modal metasomatism
Location of the study area in Eastern Algeria. a Topographic map, b sampling shallow wells
Saturation indices (SI) of groundwater from the Merdja aquifer
This work presents results of the hydrogeological and hydrochemical studies on groundwater samples from the alluvial aquifer of Merdja in Tébessa, located in the Western part of this town. Its groundwater resources are used mainly for crop irrigation in an agriculture dominated area. Hydrochemical and water quality data obtained through a sampling period (December 2008) and analysis program indicate that nitrate pollution can be a serious problem affecting groundwater due to the use of nitrogen (N) fertilizers in agriculture. The concentration of nitrate in groundwater ranged from 19 to 281 mg/l. Considerable seasonal fluctuations in groundwater quality were observed as a consequence of agricultural practices and other factors such as annual rainfall distribution and the wadi El Kebir flow regime. The chemical composition of the water is not only influenced by agricultural practices, but also by interaction with the alluvial sediments. The dissolution of evaporites accounts for part of the Na+, K+, Cl−, SO 42−, Mg2+, and Ca2+, but other processes, such as calcite precipitation and dedolomitization, also contribute to groundwater chemistry.
Iran has very high potential for production and export of dimension stone (rock quarried to size and shape specifications); nevertheless, in spite of growing mine production during the past decade, in many instances this potential has been overlooked. Construction, decorative, and facing stones of Iran are among the highest-quality products in the world. In this paper, Iran’s dimensional stone mines are analyzed using strengths, weaknesses, opportunities and threats (SWOT) analysis in combination with analytic hierarchy process (AHP). SWOT analysis is a tool commonly used for analyzing both the internal and external environments in order to attain a systematic approach and support for a decision situation. Conventionally, SWOT analysis is qualitative and does not quantify the effect of the factors. Consequently, it is not effective in priority setting. To overcome this limitation, SWOT analysis has been used in combination with other quantitative multi-criteria decision making methods especially the AHP. In this study, first an environment analysis was performed by an expert team familiar with these mines. In this way, the SWOT factors were identified and the subfactors which had very significant effects on the success of these mines were determined. Using the SWOT subfactors, the SWOT matrix and alternative strategies based on these subfactors were developed. Subsequently, the strategies were prioritized and the best strategies for Iran’s dimensional stone mines were determined. KeywordsIran’s dimensional stone mines–Strategic factors–SWOT–AHP analysis
Localization of the study areas 
Daily variation of wind run in km (S i ) of the selected sites during 2000-2005
The direction and cause of winter Shamal that persists over Arabian Gulf (Al-Baz and Makharita 1994) 
Mean July surface position of monsoon ITCZ (Pedgley 1970) 
Synoptic view of surface summer Shamal showing the location of surface high pressure and surface Low pressure zones that usually persist over the region (Pedgley, 1970)
This paper presents a rather complete picture of conditions of stagnation, recirculation and ventilation factors in the main industrialized and urban areas in Oman, developed along the coastal area. This study focuses on four sites; Sohar, Muscat, Sur, and Salalah. Each site has a local emission sources from transportation, industry and energy production activities. For the calculation of the integral quantities of the ability of the atmosphere dilution, hourly data of the wind velocity measured at a height of 10 m during 5 years (2000–2005) were used in the analysis. The results show that in the northern coast of Oman, along the bay of Sea of Oman, where 56% of the total population is concentrated and the main heavy industries of the country are amassed, the atmosphere is prone to stagnations in 74.4% of the time, while in the southern and east part of Oman, they occur only 23% and 51%, respectively. The bay of sea of Oman is high affected by land–sea breeze circulation that plays a substantial role in the simultaneous occurrence of recirculation equally to stagnation. This meso-scale effect is altered gradually during the passage of the synoptic-scale flow of the southeasterly summer monsoon that enhances the occurrence of the ventilation in Salalah (24.6% of time) and Sur (15.5%). In the northern coast of Oman, where the Hajir mountains suppressed the effect of the summer monsoon, a very weak tendency towards ventilation is observed (less than 6%). The southern summer monsoon over Oman is a source of life in this arid area and as well a source of clean air.
Prediction of blast-induced air overpressure (AOP) is very complicated and intricate due to the number of influencing parameters affecting air wave propagation. In this paper, an attempt has been made to predict the blast-induced AOP by support vector machine (SVM) using maximum charge per delay and distance from blast-face to monitoring station of AOP. To investigate the suitability of this approach, SVM predictions are compared with a generalized predictor equation. Seventy-five air blasts were monitored at different locations around three mines. AOP data sets of two limestone mines are taken for the training and testing of the SVM network as well as to determine site constants for generalized equation. The remaining mine data sets are used for the validation and comparison of AOP. التنبؤ الانفجار الناجم عن ارتفاع الضغط الجوي (اوب) أمر معقد للغاية ومعقدة نظرا لعدد من المعايير التي تؤثر التأثير على الموجات الجوية. في هذه الورقة ، وبذلت محاولة للتنبؤ وقوع الانفجار الناجم عن ارتفاع الضغط الجوي (اوب) عن طريق دعم الموجه آلة (SVM) باستخدام أقصى لكل تهمة التأخير والمسافة من الانفجار ، وجها لمحطة رصد لاوب. للتحقيق في مدى ملاءمتها لهذا النهج ، SVM التنبؤات هي مقارنة مع تنبؤ المعادلة معممة. 75 الانفجارات الجوية قد تم رصدها في مواقع مختلفة حول ثلاثة مناجم. اوب مجموعات البيانات من الحجر الجيري 2 الألغام هي التي اتخذت لتدريب واختبار شبكة SVM وكذلك لتحديد موقع لثوابت المعادلة معممة. ما تبقى من الألغام مجموعات البيانات التي تستخدم للتحقق من صحة والمقارنة اوب. KeywordsAir overpressure–Support vector machine–Generalized predictor equation
In Alborz Mountains, the thickness of sediments in Member 2 of the Mila Formation (Middle Cambrian) underwent dramatic and abrupt deformations, which were accompanied by normal and reverse faults and asymmetrical folds. These deformed sediments are covered by parallel beds both in the upper and lower sides. The existence of such extension and compression structures adjacent to each other indicates the influence of non-tectonic factors in their evolution. These deformations induced by downslope gliding of sediment packages are fully compatible with the dislocation model of Farrell (J Struct Geol 6:727–736, 1984) and Farrell and Eaton (1987). Moreover, the occurrence of synsedimentary deformations in a vast area in Alborz Mountains reinforces the probability of the impact of seismic shocks in their formation. In fact, incessant seismic events in the Middle Cambrian led to numerous submarine slumpings in the sediments of Member 2 of the Mila Formation. إذا تتبعنا في سلسلة جبال ألبرز شمالي إيران لوجدنا أن سماكة الترسبات العائدة إلى العضو2 للميلافورميشن ( العصر الكمبري الأوسط ) قد مرت بتغييرات شديدة و مفاجئة و قد صحبت هذه التغيرات تصدعات طبيعية و عكسية و تجاعيد غير متوازنة . و تغيرت أشكال هذه الرواسب و تلبست بطبقات متوازية في الأعلى و الأسفل . إن تواجد مثل هذه الهيكليات و التركيبات الامتصاصية و المتراكمة [ بفعل الضغط ] إلى جانب بعضها يدل على تأثير عوامل غيرتكتونية في مسار تطورها . مثل هذا النوع من التغيير في الأشكال و الذي يحدث إثر انزلاق [هبوط] مجموعات مترسبة [مجموعات الرواسب ] نحو الأسفل ، يطابق تماماً نموذج الانتقال Farrel and Eaton(1987) and Farrel(1984) . و إضافة إلى ذلك ، ان حدوث تغييرات في الشكل تزامناً مع الترسب في قسم واسع من سلسلة جبال البرز يعزز احتمال تأثير الصدمات الارتجاجية(الزلزالية) في تكوينها ، على ان تكون قد تسببت الارتجاجات(الزلازل) المتتالية في العهد الكمبري الأوسط في انزلاقات عديدة في أعماق البحار بالنسبة للترسبات (الجزء2) العائدة إلى الميلافورميشن . المفردات الأساسية : الميلافورميشن ، جبال البرز ، تغيرات الشكل المتزامنة للترسب ، الهبوط (slumping)
Mass movements or mass wasting is being considered as one of the severe forms of natural disasters. Iran is geographically located in the Alps–Himalaya seismicity belt. It has a high potential to mass wasting. This seismic phenomenon creates landslides and rock falls in the high mountains of Alborz and Zagros. These mass movements and various types of slides can be systematically assessed and mapped through traditional mapping frameworks using geo-information technologies. The geo-information-based technology offers the earth scientist to study and map various types of mass movement and stability of slopes. In this study, we used field data coupling with the tectonic-related factors to provide a solution for slope-related hazards. Firstly, various geological and geomorphological factors such as lineaments and faults, vegetation, lithology, slope, drainage, land use/land cover, seismicity and roads network were extracted and compiled using geo-information technology. This is because the factors mentioned above play important role in the instability of the region. Then, the study area was divided into four regions based on the rate of mass wasting and its degree of vulnerability. The results of this study showed that the erosion in Karaj formation is severe. Additionally, this research also reveals that the hydrothermal solutions caused by the erosional activities have influenced the glassy element of tuffs and subsequently changed into the clays. This change has caused the tuffs to be relatively unstable. Further, it is evident that the chemical and physical weathering has had a big impact on it whilst most of the mass wasting has occurred within the unstable tuffs of Karaj formation. Finally, the paper concluded that the recent construction of the new roads in the region has increased the potential danger for generating the mass wastes and thus makes the region more unstable.
The effects of initial state of the samples and the overconsolidation ratio (OCR) on the behavior of Chlef sand were studied in this article. For this purpose, the results of two series of undrained monotonic triaxial compression tests on medium dense sand are presented. In the first test series, the influence of the specimen's fabric and confining pressure has been studied. The tests were conducted at initial confining pressure of 50, 100, and 200 kPa. Two methods of sample preparation, which included the dry funnel pluviation and the wet deposition, were utilized. All the samples were subjected to a monotonic loading after consolidation phase. The results of the tests demonstrate that an increase in initial confining pressure leads to an increase in the resistance to liquefaction. The results also show that the samples prepared with the dry funnel pluviation method exhibit a greater resistance to liquefaction than those prepared with the wet deposition method. In the second series of tests, the overconsolidation influence on the resistance to the sand liquefaction has been realized on samples at an effective stress of 100 kPa for OCR varying between 1 and 8. The tests show that the increase of OCR improves the stiffness of sand and accelerates the appearance of dilatancy.
Mostaganem City, located in the northwestern part of Algeria, has grown and has been urbanized rapidly. The city and surrounding areas depend heavily on groundwater as a resource for drinking water, as well as domestic, industrial, and agricultural uses. Understanding the groundwater chemistry provides insight into the interactions of water with the environment and contributes to better resource management. In total, 12 groundwater samples from wells in Mostaganem City have been analyzed for major physical–chemical elements and metals. The results show that the waters have pH values ranging between 7.1 and 8.1, salinity between 226 and 1,073mg/L, and nitrate concentrations between 15 and 47.7mg/L. The high concentration of nitrates is explained by the utilization of chemical fertilizers in agriculture. Almost all samples are of type Na–SO4 and Na–HCO3, and the trace metal concentrations are within the admissible standard ranges. We conclude that the groundwater in Mostaganem may safely be used for drinking, domestic, agricultural, and industrial purposes. تقع مدينة مستغانم في شمال غرب الجزائر و قد تطورت عمرانيا بسرعة كبيرة . و نشير أيضا أن مصدر الماء الصالح للشرب والمياه المستعملة في الصناعة والزراعة حول هذه المدينة أساسه المياه الجوفية.وبما أن المعرفة الكيميائية للمياه الجوفية وتداخلها مع البيئة تساهم في عقلانية تسير المياه قمنا بهذه الدراسة التي أجرينا فيها تحليلا فيزيائيا وكيميائيا لإثني عشر عينة (12) مختلفة من الأبار المتوجدة بمدينة مستغانم. أظهرت النتائج أن فيمة الأس الهيدروجيني (pH) تراوحت بين 7.1 و 8.1 كما قدرت الملوحة بين 0.75 إلى 2.26 ملغ/ل أما فيما يخص تراكيز النترات فكانت بين 15 و 47.77 ملغ/ل ويعود هذا التركيز المرتفع للنترات بسبب إستعمال الأسمدة الأزوتية في الزراعة.أشارت التحاليل أيضا أن معظم العينات كانت من نوع NaSO4 و NaHCO3 كما أن تراكيز المعادن الثقيلة واقعة في المجال المسموح به من طرف منظمة الصحة العالمية.سمحت لنا هذه الدراسة أن نستنتج أن المياه الجوفية لمستغانم يمكن إستعمالها كمياه صالحة للشرب وفي المجلات الأخرى المختلفة.
Timimoun is located in the hyper-arid zone of the Sahara, with an annual rainfall not exceeding 100 mm/year. To fill the shortage of rainfall, the oasis has developed a traditional means for mobilization of the groundwater. In the foggara with this hydraulic system, oases have been developed throughout the region of Timimoun over ten centuries. Today, we witness the gradual disappearance of foggaras; we lose about one to two foggaras per year for over half a century. The discharge of the 250 functional foggaras shows a significant drop: 850 l/s in 1960 and 355 l/s in 2001, enough to irrigate 350 ha. The causes of declining foggaras are technical, social, and environmental. The surveys that we have led nearly with the population in the ksour during two missions in 2007 and 2008 in the oasis of Timimoun reveal that socio-economic problems (Heritage and depopulation) are common to both types of foggara (foggara of the Erg and foggara Albian). Environmental problems (silting and flooding of the galleries by wild plants) are the main causes of the disappearance of foggaras of Erg. Technical problems (collapse of tunnels) are mainly the causes of degradation to Albian's foggaras. Attempts to introduce changes to foggaras are temporary solutions. The modern collection of water (pump and drilling) is gradually replacing the traditional hydraulic system.
This paper is an assessment of the suspended sediment yield in the Mellah Catchment of northern Algeria. We use discharge-sediment load relationships to explore the variability of water discharge and sediment load, and to investigate the impact of geomorphic factors disturbance on erosion and sedimentation. Suspended sediment load was analyzed in the Mellah Catchment (550 km(2)) which was controlled by a gauging station to measure discharge and sediment transport. The relations between daily mean sediment concentration and daily mean water discharge were analyzed to develop sediment rating curves. For storms with no water samples, a sediment rating curve was developed. The technique involves stratification of data into discharge-based classes, the mean of which are used to fit a rating curve according to single flow data and season to provide various rating relationships. The mean annual sediment yield during the 24 years of the study period was 562 T km(-2) in the Mellah Catchment. This drainage basin had high rainfall and runoff, the erosion was high. The high sediment yield in the Mellah basin could be explained by a high percentage of sparse grassland and cultivation developed on shallow marly silty-clayey soils with steep slopes often exceeding 12%. Almost all suspended sediment loads are transported during storm events that mainly occur in the winter and spring heavy and medium downpours. The scarceness of these events leads to a very large interseasonal variability of the wadi sediment fluxes. The negative impacts of this enhanced sediment mobility are directly felt in the western part of the basin which shows many mass movements, bank and gully erosion because cultivated areas are often bared during autumnal brief flash floods and furrowed downslope during the winter season.
The introduction of the entropy concept in hydraulics by Chiu gives the possibility to develop a simple method to measure discharges in natural streams. The application of this method on four streams in north Algeria made a possibility to develop a linear mean–max velocity models, deduce the entropy parameters and the cross sectional areas expressions for all streams in order to obtain the water discharges easily with minimum errors. The Chiu’s velocity distribution equation was also checked for a large range of discharges, water levels, and flow pattern, where it proves its efficacy. إن إدراج مفهوم الأنتروبيا في الهيدروليك من طرف "شاولين شيو" أعطى إمكانية كبيرة لتطوير طريقة سهلة لقياس التصاريف في القنوات الطبيعية. طبيق هذه الطريقة على بعض أودية شمال الجزائر أمكن من إيجاد علاقة خطية بين السرعة القصوى و المتوسطة ،استخلاص معامل الأنتروبيا بالإضافة إلى إيجاد علاقات مبسطة لمقاطع الجريان و ذلك من أجل إيجاد التصريف بأسهل طريقة و بأقل أخطاء. علاقة توزيع السرعة" لشيو"أثبتت فعاليتها و ذلك لمجال واسع من التصاريف ، نماذج وأعماق الجريان.
Phreatic aquifers present many serious problems for local public authorities, and they have done so especially for the water resources managers in Oued-Souf, Algeria, since 1980. Recently, a perturbation in piezometric level was observed in Oued-Souf. The spatial distribution of piezometric level data was analyzed by applying geostatistical methods, which provide an indication of the uncertainty of the estimation using the computer software VARIOWIN 2.2. In this paper, the evolution of the piezometric level by referring to other research campaigns was studied. Campaigns were conducted from March 1993 to April 2002. In the beginning, elementary statistics has been carried out to understand the statistical distribution and performed an analysis of variance so that two campaigns could be chosen for comparison. Geostatistics for modeling and cartography were applied. The results show that piezometric levels admit power model that the direction of groundwater flow is from south to north and that, due to the return of irrigation water (there is no drainage system), water levels increase in places like Foulia (1.35 m), northwest of Oued-Souf (1.43 m), Kouinine (4.58 m), and Ouzitene (3.01 m). The water levels also decrease in places like Guemar, Dmitha, Rhamra, and Djeldida, from between 2 and 6 m, due to excessive pumping of groundwater.
In this study, the physicochemical parameters (Conductivity, pH, Cl−, HCO 3−, PO 43−, SO 42−, NO 3−, NO 2−, F−, TH, Ca2+, K+, Mg2+, Na+, and DS) were determined for 41 samples collected from fourteen places in Algeria. The temperature of the thermal water samples at collection sites varied from 26°C to 86°C. pH values varied from 6.5 to 8.5 (i.e., from slightly acidic to moderately alkaline); 90.24% of the samples exhibited relatively high salinity (DS = 550–5,500 mg L−1). Total hardness measurements indicated these waters to be moderately hard. Forty-six percent of the samples are Na–Cl in character. The ratios Na+/Ca2+, Na+/Mg2+, and (Na+ + K+)/(Ca2+ + Mg2+) were high in 90.24% of the samples. This indicates the ion exchange process is important, which indicates that most of the Algerian thermal waters had developed over a long period at a depth sufficient to react with the rock. Statistical analyses of the physicochemical data gave positive correlation values, thereby enabling good interpretation of the results and revealing the composition of ions present in the thermal waters, as well as some information about their origin. The therapeutic properties associated with thermal waters encourage people at spas to drink the water they bathe in. Therefore, we examined the drinkability of these thermal waters. World Health Organization (WHO 1993) standards were used to evaluate the thermal water quality for drinking. With respect to hardness, the samples were classified as moderately hard (58.54% of the samples), very hard (36.58% of the samples), and soft (4.88% of the samples). The drinkability study shows that only 16 samples of the investigated waters were drinkable and thus could be consumed without special precaution.
This paper discusses an experiment on digital imaging and visualizing the surface condition of the sediment depositions. For that purpose, a part of South Tripura district was selected as sampling site. Physically, the selected area is located in a fold belt and preserves the history of Tertiary–Quaternary landform evolution in the main types of sediment depositions. Three samples, each from the different types of Tertiary depositions, were finally taken for thick section making, optical microscopy under reflected light, and soft computing. Geometric optical measurement and physical optical measurement were done to understand the surface condition of Bokabil, Tipam, and Duplitila samples by bidirectional reflectance distribution function and radiometric scales (within 0–255 digital number values). Maximum surface smoothness or near-perfect reflection surface was measured by brightness–contrast slicing operation. هذه الدراسة تتعامل مع تجارب التصوير الرقمي وتصور حالة السطح للرسوبيات تحت الضوء المنعكس. من أجل هذا الغرض، تم اختيار جزء من منطقة جنوب تريبورا لأخذ العينات, وهى منطقة مطوية تحفظ تاريخ طويل من تطور شكل الأرض لعصري الثلاثي والرباعي في ثلاث أنواع من الرسوبيات مثل بوكابيل وتيبام و دوبيتيلا. تم أخذ ثلاث عينات من ثلاث أنواع من رسوبيات العصر الثلاثي وتم عمل قطاعات رقيقة للفحص الميكروسكوبي والحسابات الخفيفة. تم عمل قياسات بصرية هندسية وفيزيائية لفهم حالة السطح لعينات بوكابيل وتيبام و دوبيتيلا بواسطة مقياس BRDF والمقياس الراديوميترى فى حدود قيم 0-0-255 DN. تم قياس أعلى نعومة سطحية أو الانعكاس شبه التام للسطح بعملية تشريح التباين في درجة السطوع (BCS). KeywordsReflectance–BRDF–Microfacets–Brightness–contrast slicing–Near-perfect reflection surface
Freundlich isotherm for stilbite Fig. 5 Removal metal for various exchangers and resin dose  
Freundlich isotherm for stilbite Fig. 5 Removal metal for various exchangers and resin dose  
Chaiacteristics of the resins tested
Freundlich isotherm for CSA-9  
Freundlich isotherm for CSA 609D  
The mining industry faces stringent effluent discharge regulations and has acknowledged that it is necessary to look into innovative technologies to recycle considerable amount of effluent rather than discharging into surface water. Effluents from mines give rise to aesthetic unpleasantness. The focus of the investigations was to cope with more stringent effluent discharge regulations and to protect the ecosystem from harmful pollutants in the mine effluents. Copper is one of the heavy metal in the mine systems, which are known to be a harmful element. The present study has been undertaken to investigate a process that might remove Cu(II) from mine waste water by using natural zeolite, such as stilbite, and compared with synthetic resins like CSA-9 and CSA-609D. In this study, natural zeolite was used as a low-cost adsorbent to evaluate its ability to remove heavy metals from acid mine drainage. The zeolite used in this study is the natural clay mineral from the Nizarneshwar Hills of Western India. Three resins tested are CSA-9, natural zeolite-stilbite, and CSA-609D. Batch testing has been conducted to select effective ion-exchange resins for copper removal and to determine effective regenerants for regeneration of exhausted resins. All tests were conducted at bench scale and in batch mode. Three strong acid cation exchangers were evaluated to compare their metal removal capacities. The metal concentration in the effluent was reduced with all resins tested. It was found that, among all the three types of natural zeolite, stilbite shows the highest removal efficiency of copper in every parameter that is considered for evaluating the performance of resins.
Urban, industrial, and tourist developments are considered of high priority in Egypt. In the current research, the site suitability investigation for rating the different environmental, geological, and geotechnical conditions facing civil engineering projects were assessed using a geographic information system (GIS) multi-criteria approach. The study area is one of the most promising areas for urban and touristic as well as industrial developments in Egypt, which is located on the NW coast of the Gulf of Suez. This area may face several geo-environmental problems that will limit its suitability for civil projects. Weighted GIS model, which integrates different types of data sources, such as land use/cover, geological, geomorphological, geophysical, environmental, remote sensing, and field data, can be achieved to create a site suitability map. In this paper, an analytical hierarchy process approach has been used to develop the weighted model for different factors. As a result of this study, areas of potential geotechnical and geo-environmental hazards that could impact the design and construction of civil projects were identified. Therefore, changes can be made early in the design process before significant design efforts are being invested.
One of the major problems encountered in characterizing fluid movement and solute transport in fractured media is how to deal with the high degree of complexity and heterogeneity in these media. To understand the physical transport mechanisms of contaminant in a single fracture, tracer tests were carried out using an artificially fractured chalk block (17 x 15 x 14 cm(3)). Sorptive and diffusive properties of chalk were evaluated by performing batch and diffusion experiments. The simulation of the breakthrough curves (BTCs) with the single fissure dispersion model could not give reasonable fit. A multi-channel dispersion model with the superposition of BTCs of at least two different flow paths resulted in an acceptable fit. Those simulations indicate the existence of flow channeling effects within the fracture. Comparing the BTCs of nitrate and eosin implied possible adsorption and/or degradation of nitrate within the fracture and the matrix. High dispersivity values are observed which might be explained as a result of spreading of the tracer pulses by diffusion into different flow channels and/or stagnant water zones. The description of the observed BTCs with a multi-channel model is still a theoretical suggestion and needs more investigations to be confirmed.
Detailed geophysical measurements have been carried out in the northwestern part of the Sinai Peninsula. This area was mainly used by the ancient Egyptian army forces to support the trading and mining trips to Sinai and Asia. The geophysical field work aimed to discover new buried archeological remains using the efficient archeogeophysical detailed and nondestructive methods including total magnetic field, vertical magnetic gradient, and very-low-frequency electromagnetic measurements. Results of the field geophysical measurements have led to a discovery of a temple which is located on the Horus military road. This discovery has been verified by an excavation program, under the supervision of the Supreme Council of Egyptian Antiquities, where buried remains of a pharaoh’s temple were detected and photographed. Some other sites were recommended for further excavation in the future. تم فى هذا البحث تنفيذ قياسات جيوفيزيائية تفصيلية فى الجزء الشمالى الشرقى من شبه جزيرة سيناء حيث كانت هذه المنطقة تستخدم بواسطة القوات الحربية المصرية فى العصر الفرعونى لحماية أنشطة التجارة والتعدين لسيناء وقارة أسيا. وتهدف هذه القياسات ، التى تضمنت قياس المجال المغناطيسى الكلى والتدرج المغناطيسى الرأسى والموجات الكهرومغناطيسية منخفضة التردد ، الى اكتشاف بقايا أثرية جديدة فى منطقة الدراسة. توصلت نتائج القياسات الجيوفيزيائية الحقلية الى اكتشاف معبد فرعونى على طريق حورس الحربى. وقد تأكدت نتائج هذه الدراسة باجراء برنامج حفر تحت اشراف المجلس الأعلى للأثار المصرية حيث تم العثور على المعبد المذور وتصويره. توصى هذه الدراسة باستمرار عمليات الاستكشاف الجيوفيزيائى فى المنطقة لامكانية اكتشاف مواقع أثرية أخرى. KeywordsEgypt-Sinai-Geophysics-Archeology-Magnetic-VLF-EM-VLF-R
The protection and preservation of groundwater resources are compulsory, particularly in the arid and semiarid countries where the waters are scarce. The effects of increasing urbanization, economic development, and agricultural activities, along with the erratic and scarce rainfall, contribute to the quantitative and qualitative deterioration of these resources. This paper attempts to produce groundwater vulnerability and risk maps for the Angad transboundary aquifer using DRASTIC model. The data which correspond to the seven parameters of the model were collected and converted to thematic maps in Geographic Information System environment. The modified DRASTIC map, which is the summation of the DRASTIC index and the network fractures maps, shows two degreed of vulnerability: medium and high. This map is then integrated with a land use map to assess the potential risk of groundwater to pollution in the Angad transboundary aquifer. There are three risk zones that are identified: moderate, high, and very high. إن حماية الثروات المائية الجوفية أمر مهم, خاصة في المناطق الجافة و الشبه الجافة المعروفة بقلة هذه الثروات. يعتبر التوسع الحضري و النمو الاقتصادي إضافة إلي الأنشطة الفلاحية المصحوبة بقلة التساقطات المطرية من أهم العوامل المؤدية إلي التدهور الكمي والنوعي للثروات الجوفية المائية. هذا المقال يهدف إلي إنشاء خارطتي الهشاشة و المخاطر الخاصة بالمائدة المائية لمنطقة أنكاد الحدودية وذلك باستعمال الأنموذج الدراستيكى. المعطيات الخاصة بالمقاييس السبع المكونة للأنموذج ثم جمعها و تحويلها إلي خرائط موضوعية بإدماجها في نظم المعلومات الجغرافية. الخارطة الدراستيكية المنقحة الناتجة عن جمع خارطة المعامل الدراستيكى و خارطة شبكة الانكسارات تبين نوعين من الهشاشة: متوسطة و عالية. هذه الخارطة تم جمعها فيما بعد مع خارطة استخدامات الاراضى من اجل اختبار مخاطر تلوث مياه المائدة المائية لمنطقة أنكاد الحدودية. ثلاث مناطق تم رصدها: متوسطة, عالية و جد عالية. KeywordsWater management-Groundwater vulnerability-Pollution-DRASTIC index-Morocco
A multivariate geostatistics (cokriging) is used for regional analysis and prediction of rainfall throughout the southwest region of Saudi Arabia. Elevation is intruded as a covariant factor in order to bring topographic influences into the methodology. Sixty-three representative weather stations are selected for a 21-year period covering different microclimate conditions. Results show that on an annual basis, there is no significant change using elevation. On the seasonal basis, the cokriging method gave more information about rainfall occurrence values, its accuracy related to the degree of correlation between elevation and rainfall by season. The prediction of spring and winter rainfall was improved owing to the importance of orographic processes, while the summer season was not affected within its monsoon climatology. In addition, fall season shows inverse and weak correlation of elevation with rainfall. Cross-validation and cokriging variances are also used for more accuracy of rainfall regional estimation. Moreover, even though the correlation is not significant, the isohyet values of cokriged estimates provided more information on rainfall changes with elevation. Finally, adding more secondary variables in addition to elevation could improve the accuracy of cokriging estimates.
One of the most important scientific concerns of the last few decades is climate change, which is the result of a great many factors like global warming. Although a number of studies have been dedicated to understand the phenomenon of climate change, more attention is required to understand the potential effects of global warming on the ecosystems as well as on human life. The present study was designed to survey the trends of minimum, maximum and mean temperatures, relative humidity, and the time series of annual precipitation and 10-year moving average low-pass filter in the 13 synoptic weather stations of Iran's arid and semi-arid regions during the last 55 years by using tau Kendall test. The analyses indicate a significantly increasing trend for the minimum and mean temperatures while a decreasing trend for the mean relative humidity in the arid and semi-arid regions, especially during the last few years up to the year 2000. Any clear increasing or decreasing trend was not found for the maximum temperature, while the precipitation did not show any increasing/decreasing trend for most of the surveyed stations. Further studies, with long-term programming, are recommended to be carried out to evaluate the climate change and its effects on such regions.
The present study deals with processing and interpreting the potential gravity and magnetic data in order to locate promising sites for metallic mineral occurrences in the basement rocks of South Sinai. Two promising sites were anticipated by combining the geophysical results and the available geological information. Each site was profiled and interpreted to the nearly approximated subsurface feature model, and the geometrical parameters of the expected subsurface structures may form mineralized bodies such as depth, thickness, width, dipping, density contrast, and magnetic susceptibility contrast could be delineated. Detailed ground Very Low Frequency (VLF) and Vertical Magnetic Gradient (VMG) methods were carried out in the site A2, eight VLF and VMG anomalies were determined, and their depths were calculated.
A new approach is developed to determine the model parameters of a two-dimensional inclined sheet from self-potential anomaly. In this method, the numerical horizontal self-potential gradient obtained from self-potential anomaly is convolved using Hilbert transform to obtain the vertical self-potential gradient. The complex gradient is the sum of horizontal and vertical gradient anomalies. The horizontal and vertical gradients are plotted in one graph to form the complex gradient graph. By defining few characteristic points and distances along the complex gradient profile, procedures are then formulated using the analytical functions of the complex gradients to obtain the model parameters of sheet-like structures. The validity of the new proposed method has been tested on synthetic data with and without random noise. The obtained parameters are in congruence with the model parameters when using noise-free synthetic data. After adding 10% random error in the synthetic data, the maximum error in model parameters is 11.8%. Moreover, the method have been applied to analyze and interpret the self-potential anomaly measured on a graphite ore body at southern Bavarian woods, Germany to prove its efficiency where an acceptable agreement has been noticed between the obtained results and the other published results.
Mesozoic oil in Saudi Arabia exists in north/south-oriented anticlines. Such anticlines are usually studied using subsurface data. The present study introduces, for the first time in Saudi Arabia, a surface analog for these anticlines. The study covers two northerly oriented anticlines located in the Jinadriyah area at 15 km to the northeast of the Riyadh city. They are named herein the North and South Jinadriyah anticlines. The outcrops in both anticlines belong to the Lower Cretaceous Yamama Formation which consists of limestone in its lower part and limestone with shale in its upper part. The study included initially detailed interpretation of Google Earth and Landsat TM images to map the structural pattern of the anticlines. Detailed field mapping confirmed the satellite image interpretation and helped describe the geometry of the two anticlines in detail. The 3.5-km-long South Jinadriyah anticline is an open doubly plunging asymmetric anticline. The western flank is dissected by 13 minor reverse faults of north-south orientation. The North Jinadriyah anticline is about 5.5 km long and is relatively more complex than the South Jinadriyah anticline. It consists of northern, central, and southern segments that differ from each others in orientation and style. The anticline is dissected by 18 minor faults of different orientations and sense of displacement. Two perpendicular fracture sets with one being parallel to the anticline axes were recorded in the two anticlines. Both anticlines are interpreted as fault-propagation folds that were formed during the Late Cretaceous first Alpine orogeny. The mid-Late Tertiary second Alpine orogeny and Late Tertiary eastward tilting of the Arabian Plate increased the degree of folding and faulting.
This paper aims to simulate the kinematic evolution of a regional transect crossing the Northern Emirates in the northernmost part of the Semail Ophiolite and the Dibba zone, just south of the Musandam Platform exposures. The studied section comprises, from top to bottom and from inner to outer zones, (1) the erosional remnants of the Semail Ophiolite, mainly made up of serpentinized ultramafics in the west and gabbros in the east, (2) high-grade metamorphic rocks which are currently exposed in the core of a nappe anticline near Masafi, (3) far-travelled Hawasina basinal units and Sumeini paleo-slope units of the Dibba Zone, (4) parautochthonous platform carbonates, which are currently well exposed in the Musandam area, and (5) a flexural basin filled with uppermost Cretaceous to Neogene sediments. Two main compressional episodes are generally identified, resulting first in the obduction of the Semail Ophiolite and then in the stacking of underlying platform carbonate units of the former Arabian passive margin, thus accounting for the present architecture of this transect: (1) first, deformation at the plate boundary initiated in the Late Cretaceous, resulting in the obduction of the Semail Ophiolite and the progressive accretion of the Hawasina and Sumeini tectonic wedge on top of the Arabian foreland, leading to a progressive bending of its lithosphere and development of a wide flexural basin; (2) compression resumed during the Neogene, leading to the tectonic stacking of the parautochthonous platform duplexes of Musandam and Margham trends, the development of out-of-sequence thrusts and triangle zones, refolding of the sole thrust of the former Late Cretaceous accretionary wedge and coeval normal (?) high-angle faulting along the contact between the Musandam and Dibba zones. However, seismic profiles and paleo-thermometers also help in identifying another erosional event at the boundary between the Paleogene Pabdeh and the Neogene Fars series. Evidenced by the local erosional truncation of the Pabdeh series in the vicinity of the frontal triangle zone (i.e. the inner part of the former Late Cretaceous foredeep), this Paleogene uplift/unroofing episode is tentatively interpreted here as an evidence for a continuum of compressional deformation lasting from the Late Cretaceous to the Middle Miocene although one may alternatively speculate that it was related to the detachment of the subducted slab. Although carbonate facies are usually not suitable for apatite fission track (AFT) studies, we were able to extract detrital apatites from quartz-bearing Triassic dolomites in the Musandam area. However, the yield and the quality were both poor and too few fission track lengths could be measured, making it difficult to interpret the meaning of the FT ages. The FT dates obtained in this study are therefore compared with those existing in the literature. Fortunately enough, for each sample, at least ten apatite crystals could be used for fission track dating, except for site 6 with only five datable apatite grains. The obtained apatite fission track dates between 28 and 13Ma, much younger than the Triassic age of the series, are taken to represent reset fission track ages, implying erosion of an up-to-3-km-thick pile of Jurassic–Cretaceous carbonates and Hawasina allochthon during the Neogene. Apatite fission track dates from the ~95M-old plagiogranites of the Semail complex (Searle and Cox, Geol Mag 139(3):241–255, 2002) obtained in this study and compared with those recently published provide evidences for more than one cooling event. An early unroofing of the ophiolite during the Late Cretaceous is revealed in fission track dates of 72–76Ma at the top of the ophiolite in the east, which are coeval and also consistent with the occurrence of paleo-soils, rudists and paleo-reefs on top of serpentinized ultramafics in the west. High-pressure rocks at As Sifah in the southeast near Muscat revealed apatite fission track data ranging from ~46 to 63Ma (Gray et al. 2006). The leucocratic part of the ophiolite (sample UAE 180) yielded comparable young apatite (40.6 ± 3.9Ma) and zircon (46.6 ± 4.3Ma) FT dates. A Cenozoic (~20–21Ma) exhumation has been determined for the Bani Hamid metamorphic sole in northern Oman, applying low temperature geochronology and combining apatite FT and apatite (U–Th)/He analyses (Gray et al. 2006). In this study, young apatite fission track dates of 20Ma have also been found but at the base of the ophiolite near Masafi, in the core of the nappe anticline, thus indicating a Neogene age for the refolding of the allochthon and stacking of underlying parautochthonous platform carbonate units. During the subsequent 2D forward Thrustpack kinematic modelling of the regional transect, these AFT data-set has been used, together with available subsurface information, to reconstruct the past architecture of the structural sections through time, accounting for incremental deformation along the various decollement levels, synorogenic sedimentation and erosion, as well as for successive bending and unbending episodes of the Arabian lithosphere. ـيهتم هذا البحث بدراسة التطور الحركي لمنطقة شمال الإمارات من صخور الأفيولايت في منطقة سيمال ونطاق ديبا. والمقطع الذي تم دراسته يقارن ما يلي:(1) – البقايا الناتجة من تعرية أفيولايت سيمال (منطقة في عُمان)، (2) – الصخور ذات التحول العالي، (3) – صخور من حوض حوسان ووحدة سوماني من نطاق ديبا، (4) – متكون الكربونايت الذي يأخذ شكل الهضبة وله مكاشف واضحة في منطقة موساندم، (5) – الحوض المتعرج الممتلئ برواسب من الكريتاوي والنيوجين. هناك مرحلتان من الضغط تم ملاحظتهم في المنطقة: الأولى تشوه حواف الصفيحة في نهاية العصر الكريتاوي، الثانية ضغط واضح في عصر النيوجين بسبب نطاق دفع وصدع ثلاثي زاوي مع إعادة الطي وحدوث صدوع زاوية حادة على طول التماس بين نطاق ديبا ومنطقة سد موساندم. دراسة التحليل الإشعاعي للأباتيت (AFT) والتاريخ الجيولوجي أعطى انطباع أن هناك عملية حت لكتلة ضخمة ذات سمك يصل إلى 3 كيلومتر من العمر الجوراسي والكريتاوي. وكذلك وجود الكربونات والرواسب الحديثة في حوسان طوال عصر النيوجين وتبين كذلك من تحليل الأباتيت أن هناك أدلة على حدوث أكثر من مرحلة تبريد للصفيحة. وفي دراسة عمق الأفيولايت في منطقة مسافي تبين أن العمر هو 20 مليون سنة. ومن دراسة (AFT) وربطها مع المعلومات التحت سطحية يمكن أن يعطي فكرة عن إعادة بناء وتكوين القطاع التركيبي خلال العمر الزمني للمنطقة. وترسب هناك رواسب تزامنت مع عمليات التعرية مما سبب تقوسات متتالية ومتتابعة ومراحل من عدم التقوس للقشرة. KeywordsKinematic modeling-Oman Mountains-Fission tracks-Tectonics
Top-cited authors
Biswajeet Pradhan
  • University of Technology Sydney
Mehdi Vafakhah
  • Tarbiat Modares University
Mohammad Zare
  • University of Tehran
Candan Gokceoglu
  • Hacettepe University
Majid Mohammadi
  • University of Tehran