The scarp lands of Saudi Arabia     

Randolf Rausch  Theo Simon  Hussain Al Ajmi  Heiko Dirks 《Arabian Journal of Geosciences》2014,7(6):2437-2450

In central Saudi Arabia, the combination of rock types and sedimentary bedding created a unique scarp landscape. The escarpments were formed during Late Miocene through Early Quaternary times. At present, cuesta formation and migration are restricted to the actual escarpments as a consequence of negligible sediment removal. The plains between the escarpments are sealed through periodically active fluvial processes and through eolian sedimentation. In this publication, the major escarpments of central Saudi Arabia are described. The interactions between tectonics, climate, and morphogenesis which created this unique landscape are reviewed.  相似文献   

Evolution of Pleistocene travertine depositional system from terraced slope to fissure-ridge in a mixed travertine-alluvial succession (Jebel El Mida,Gafsa, southern Tunisia)     

Mohsen Henchiri  Walid Ben Ahmed  Andrea Brogi  Mehmet Cihat Alçiçek  Ramdhane Benassi 《Geodinamica Acta》2017,29(1):20-41

The Quaternary stratigraphic record of Jebel El Mida, composed of continental deposits, is a useful example of concomitant travertines and alluvial deposition in an extensional setting. Travertine deposition occurred in a faulted Pleistocene alluvial fan giving rise to seven (recognised) facies interfingering with five other alluvial ones. The travertine depositional events indicate a tectonically driven evolution from terraced slope (facies group FC1–FC6) to a travertine fissure ridge-type depositing phase (facies group of FC1–FC7). Interfingering between travertine and alluvial facies indicates the co-existence of adjacent and time-equivalent depositional environments. The travertine deposition resulted from deep origin hydrothermal fluids channelled along damaged rocks volumes associated to a regional fault system, named as the Gafsa Fault (GF). The travertine–terrigenous succession in Jebel El Mida highlights the major role played by the GF in controlling: (i) the hydrothermal fluid flow, still active as also indicated by the numerous thermal springs aligned along the fault zone; (ii) paleoflow directions, discharge locations, volume, rate and fluctuations of the water supply. The paleoclimatic correlation with adjacent localities reveals that, at that time, humid episodes could have contributed to the recharge of the hydrothermal system and to the deposition of alluvial sediments.  相似文献   

The External Tanger Unit (Intrarif sub-Domain,External Rifian Zones,Morocco): an interdisciplinary study   总被引：1，自引：0，他引：1  

Soufian Maaté  Francisco Javier Alcalá  Francesco Guerrera  Rachid Hlila  Alí Maaté  Manuel Martín-Martín  Giuliana Raffaelli  Francisco Serrano  Mario Tramontana 《Arabian Journal of Geosciences》2017,10(24):556

The External Tanger Unit represents one of the most complete Cretaceous-Miocene successions in the central areas of the Internal Intrarif sub-Domain (External Rif Zones, Morocco). An interdisciplinary study has been carried out to propose a new characterization of this unit which would allow a better comprehension of the confused and complex relationships among different units of the same sub-domain. The results achieved can be summarized as follows: (1) redefinition of the stratigraphic (litho-, bio-, and chrono-) record and introduction of a new, informal lithostratigraphic terminology; (2) recognition of two main depositional sequences (lower-middle Eocene p.p. and lower Oligocene p.p.-lower Miocene p.p.) separated by extended gaps (latest Cretaceous-early Eocene p.p. and middle Eocene p.p.-early Oligocene p.p.); (3) reconstruction of the evolution of the sedimentary realm, and of the relationships between tectonics and sedimentation; and (4) comparison between the upper Cretaceous-Miocene stratigraphic record and tectonic events of the Intrarif, which is located in the western external portion of the Maghrebian Flysch Basin, and the equivalent sedimentary record of the eastern portion of this basin in the Tunisian Tell. More in general, our results allowed (i) a first reconstruction of the Cretaceous-Miocene main tectono-sedimentary events; (ii) a more detailed location of the sedimentary suite in the external African Margin in the context of a wider palaeogeographic framework; and (iii) the definition of the main stages of the geological evolution of the area.  相似文献   

Weighted Pivot Coordinates for Compositional Data and Their Application to Geochemical Mapping     

Karel Hron  Peter Filzmoser  Patrice de Caritat  Eva Fišerová  Alžběta Gardlo 《Mathematical Geosciences》2017,49(6):797-814

The log ratio methodology converts compositional data, such as concentrations of chemical elements in a rock, from their original Aitchison geometry to interpretable real orthonormal coordinates, thereby allowing meaningful statistical processing and visualization. However, it must be taken into account that the original concentrations can be flawed by detection limit or imprecision problems that can severely affect the resulting coordinates. This paper aims to construct such orthonormal log ratio coordinates, called weighted pivot coordinates, that capture the relevant relative information about an original component and treat the redundant information in a controlled manner. Theoretical developments are supported by a thorough simulation study. Weighted pivot coordinates are then applied to the geochemical mapping of catchment outlet sediments from the National Geochemical Survey of Australia illustrating their advantage over possible alternatives.  相似文献   

Broad band filter colours and optical depth of the G and L impact sites of comet shoemaker-levy 9     

M. A. Al Saud  A. A. Malawi  H. M. Basurah  Y. M. Al-Mleaky 《Earth, Moon, and Planets》1996,75(3):147-155

The crash of comet Shoemaker-Levy 9 fragments with Jupiter was observed at Aziziah Observatory, Hail, in Saudi Arabia. Three different observational methods (CCD photometric, spectroscopic, and photoelectric photometric) were used. The observations began on the 13th of July and ended on the 23 of July 1994. The CCD photometric results of the impact of fragmentsG andL are presented here, showing clearly the dark clouds resulted from those impacts. The measurements of the Titanium Oxide (TiO) absorption depth of impactsG andL showed an increase compared to the absorption depth of undisturbed regions, which indicates an increase in the TiO abundance. The increase in the colour reddening towards shorter wavelength found inG andL impacts indicate a composition of small size dust particles. Based on observations obtained at Aziziah Observatory, Saudi Arabia.  相似文献   

Finite strain analysis for deformed Neoproterozoic rock associations of the Al Amar fault zone,Eastern Arabian Shield,Saudi Arabia     

Mohammed  Lami Abdel Karim Nouaman  Kassem  Osama Mohamed Kaoud  Al Bassam  Abdel Aziz Mohamed 《Arabian Journal of Geosciences》2020,13(6):1-6

Arabian Journal of Geosciences - In this work, quantitative analysis of coastal zone landform morphology is carried out through the integration of landscape index, remote sensing (RS) and...  相似文献   

Impacts of Water Quality on the Spatiotemporal Susceptibility of Water Distribution Systems     

Md Maruf Mortula  Tarig A. Ali  Rehan Sadiq  AlaEldin Idris  Asam Al Mulla 《洁净——土壤、空气、水》2019,47(5)

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Efficient and accurate edge‐preserving smoothing for 3D hexagonally sampled seismic data          下载免费PDF全文

Haroon Ashraf  Wail A. Mousa  Saleh Al‐Dossary 《Geophysical Prospecting》2017,65(3):696-710

The automatic detection of geological features such as faults and channels is a challenging problem in today's seismic exploration industry. Edge detection filters are generally applied to locate features. It is desirable to reduce noise in the data before edge detection. The application of smoothing or low‐pass filters results in noise suppression, but this causes edge blurring as well. Edge‐preserving smoothing is a technique that results in simultaneous edge preservation and noise suppression. Until now, edge‐preserving smoothing has been carried out on rectangular sampled seismic data. In this paper, an attempt has been made to detect edges by applying edge‐preserving smoothing as a pre‐processing step in the hexagonally sampled seismic‐data spatial domain. A hexagonal approach is an efficient method of sampling and has greater symmetry than a rectangular approach. Here, spiral architecture has been employed to handle the hexagonally sampled seismic data. A comparison of edge‐preserving smoothing on both rectangular and hexagonally sampled seismic data is carried out. The data used were provided by Saudi Aramco. It is shown that hexagonal processing results in well‐defined edges with fewer computations.  相似文献   

Estimating Groundwater Mounding in Sloping Aquifers for Managed Aquifer Recharge          下载免费PDF全文

Vitaly A. Zlotnik  Anvar Kacimov  Ali Al‐Maktoumi 《Ground water》2017,55(6):797-810

Design of managed aquifer recharge (MAR) for augmentation of groundwater resources often lacks detailed data, and simple diagnostic tools for evaluation of the water table in a broad range of parameters are needed. In many large‐scale MAR projects, the effect of a regional aquifer base dip cannot be ignored due to the scale of recharge sources (e.g., wadis, streams, reservoirs). However, Hantush's (1967) solution for a horizontal aquifer base is commonly used. To address sloping aquifers, a new closed‐form analytical solution for water table mound accounts for the geometry and orientation of recharge sources at the land surface with respect to the aquifer base dip. The solution, based on the Dupiuit‐Forchheimer approximation, Green's function method, and coordinate transformations is convenient for computing. This solution reveals important MAR traits in variance with Hantush's solution: mounding is limited in time and space; elevation of the mound is strongly affected by the dip angle; and the peak of the mound moves over time. These findings have important practical implications for assessment of various MAR scenarios, including waterlogging potential and determining proper rates of recharge. Computations are illustrated for several characteristic MAR settings.  相似文献   

Seismic behavior and zoning of the sabkha soils in Jubail industrial city,Saudi Arabia     

H. R. Ahmed  N. A. Al Shayea 《Journal of Seismology》2017,21(5):1145-1169

This study aimed at the micro-level seismic behavior and zoning of the saline sabkha strata in Jubail industrial area in Eastern Saudi Arabia. It encompasses the evaluation of the site-specific seismic response parameters and the liquefaction potential for various possible subsurface conditions under the probable seismic event(s). The approach to achieve the objectives of this study included the following: analysis of geologic, hydrologic, and geotechnical data of the area; performance of field and laboratory dynamic testing; and dynamic modeling and analysis of the subsurface profiles. The results of the simulation have been used to develop liquefaction potential maps and site-specific spectra of the study area, consisting of ten seismic zones under a range of probable peak horizontal ground acceleration (PHA). Results do not show significant probability of liquefaction of the loose soil layers in the study area at the maximum possible design PHA of 0.035 g; however, liquefaction is anticipated at higher PHA values. Site-specific spectral response resulted in values of S _s and S ₁ spectral accelerations to be different as compared to those suggested by local standards. The resulting seismic micro-zonation maps and the corresponding parameters are very useful for the stability analysis of the existing and planned structures in the Jubail area.  相似文献