Geosites inventory of the northwestern Tabular Middle Atlas of Morocco   总被引：1，自引：0，他引：1  

Mohamed El Wartiti  Amina Malaki  Mohamed Zahraoui  Abdelilah El Ghannouchi  Felice Di Gregorio 《Environmental Geology》2008,55(2):415-422

Across the northwestern Tabular Middle Atlas of Morocco there are many examples of landscapes, rocks and fossils that provide key evidence of a particular moment or period in Earth history. Such Earth heritage sites are important for educating the general public in environmental matters. They also serve as tools for demonstrating sustainable development and for illustrating methods of site conservation as well as remembering that rocks, minerals, fossils, soils, landforms form an integral part of the natural world. The significance of certain sites for aesthetic or tourism reasons is obvious. There are numerous geosites, which could contribute to effective exploitation of geotourism, often in conjunction with ecotourism. The strategy employed to such sites involves close consultation with all communities in the vicinity of the respective geosite and is not only aimed at tourism and education, but also at sustainable improvement of the infrastructure of the people of this area. Geological heritage sites, properly managed, can generate employment and new economic activities, especially in regions in need of new or additional sources of income.  相似文献   

Effect of hot dry summer tropical climate on forage intake and milk yield in Holstein–Friesian and indigenous zebu cows in Sudan     

Muna Mahjoub M Ahmed  Adam Ibrahim El Amin 《Journal of Arid Environments》1997,35(4):737-746

The effects of dry summer ambient temperature on some physiological and productive responses were studied in an exotic European breed (Holstein–Friesian) and a local zebu breed (Butana ecotype) of cattle in Sudan. Rectal temperature and respiration rate were positively correlated, and dry matter intake and milk yield were negatively correlated with variation in ambient temperature. However, significant adverse effects on high ambient temperature were only observed in the exotic breed.  相似文献   

Compositional homogeneity in low-temperature chlorites     

B. Velde  N. El Moutaouakkil  A. Iijima 《Contributions to Mineralogy and Petrology》1991,107(1):21-26

Electron microprobe analyses of small chlorite grains (10–20 μm width) in diagenetically altered rocks from three deep wells and a series of outcrop samples ranging in maximum age from 4 to 1300 Ma show an increasingly smaller range in grain-to-grain composition as a function of the average age of the specimens in a series. The scatter of composition in a sample in each series changes little with depth despite present day, or estimated maximum temperature differences of 70° C to 100° C from top to bottom. Comparison of these chlorite compositions with those published for geothermal and metamorphic rocks formed under conditions of 300–450° C indicates that the homogeneity of chlorite composition is a function of both the temperature of equilibration and its duration. Apparently total homogenization of Fe/(Fe+Mg), Al/(Al+Mg+Fe) content will occur after 10¹⁰ years at low temperatures. Simple calculations indicate that a slow process such as solid state diffusion could be responsible for the eventual homogenization of mineral grain composition to reach chemical equilibrium after phase equilibrium has been reached.  相似文献   

Manganese deposits in a Carboniferous paleokarst profile,Um Bogma region,west-central Sinai,Egypt     

M. A. El Sharkawi  M. M. El Aref  A. Abdel Motelib 《Mineralium Deposita》1990,25(1):34-43

The Carboniferous carbonates of the Um Bogma Formation of the west-central Sinai include two rock successions. The lower succesion consists of karstic carbonates, intrakarstic products, weathering varieties, manganese deposits, and soil cover. The lower karstic rocks and the associated soil cover are preserved under a rhythmic alternation of dolostone and shale forming the upper rock succession of the Um Bogma Formation. The all over congruent relations between the manganese deposits and the fossilized karst profile, karst products, and the associated pedogenesis demonstrate the role of weathering in the accumulation of these deposits during Carboniferous karstification. It is clear that the manganese oxides were deposited during the mature stage of Carboniferous karstification, i.e., during the soil formation, preceeding initial diagenetic change of the karstic rocks and final deposition of the related late-diagenetic caliche cement. The geochemical behavior of Mn during the karstification and the microbiological processes involved in pedogenesis played an essential role in the concentration of the manganese ore in the subsoil horizon of the paleokarst profile. The Um Bogma Formation has been subjected to another episode of karstification during the Quaternary and resulted in lowering of the landforms of the Carboniferous carbonates and destruction of the Carboniferous karst and the associated manganese deposits in some localities.  相似文献   

Dynamic linkages among energy consumption,air pollution,greenhouse gas emissions and agricultural production in Pakistan: sustainable agriculture key to policy success     

Muhammad Imran Qureshi  Usama Awan  Zeeshan Arshad  Amran Md. Rasli  Khalid Zaman  Faisal Khan 《Natural Hazards》2016,80(1):367-388

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Structural,mineralogical, and paleoflow velocity constraints on Hercynian tin mineralization: the Achmmach prospect of the Moroccan Central Massif     

El Mahjoub Mahjoubi  Alain Chauvet  Lakhlifi Badra  Stanislas Sizaret  Luc Barbanson  Abdelkader El Maz  Yan Chen  Méderic Amann 《Mineralium Deposita》2016,51(3):431-451

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Radiocarbon dating and the <Superscript>36</Superscript>Cl/Cl evolution of three Great Artesian Basin wells at Dalhousie,South Australia     

Usama A. Abu Risha 《Hydrogeology Journal》2016,24(4):987-1000

The use of ¹⁴C (half-life?=?5,730 years) in modeling the evolution of the ³⁶Cl/Cl ratios in groundwater is reported for the first time. The complexity of the Cl–³⁶Cl system due to the occurrence of different Cl and ³⁶Cl sources and the difficulty of the determination of the initial groundwater ³⁶Cl/Cl ratios have raised concerns about the reliability of using ³⁶Cl (half-life?=?301 thousand years, a) as a groundwater-dating tool. This work uses groundwater ¹⁴C age as a calibrating parameter of the Cl–³⁶Cl/Cl decay-mixing models of three wells from the southwestern Great Artesian Basin (GAB), Australia. It aims to allow for the different sources of Cl and ³⁶Cl in the southwestern GAB aquifer. The results show that the initial Cl concentrations range from 245 to 320 mg/l and stable Cl is added to groundwater along flowpaths at rates ranging from 1.4 to 3.5 mg/l/ka. The ³⁶Cl content of the groundwater is assumed to be completely of atmospheric origin. The samples have different Cl–³⁶Cl/Cl mixing-decay models reflecting recharge under different conditions as well as the heterogeneity of the aquifer.  相似文献   

Combination of a geographical information system and remote sensing data to map groundwater recharge potential in arid to semi-arid areas: the Haouz Plain,Morocco     

Ouassil Ait El Mekki  Nour-Eddine Laftouhi 《Earth Science Informatics》2016,9(4):465-479

Arid to semi-arid regions are characterized by low levels of surface water and low annual precipitation (generally <350 mm/year). In such areas, groundwater must be used to meet all the needs of the population for water. As a consequence, careful management is required to ensure the sustainability of this scarce resource in response to the demands of urban centers, industry, agriculture, and tourism. The concept of the aquifer recharge rate is particularly useful in the quantification of these groundwater resources and can be used to form the basis of a decision support system. This study determined the potential recharge rate in the Haouz aquifer using a multi-criteria analysis that included both the major and minor factors influencing the rate of infiltration of water into the aquifer. The analysis was based on the use of a geographical information system supported by remote sensing techniques to develop thematic data layers. These layers were then used to describe the spatial variation of the factors influencing the recharge rate of the aquifer and were subsequently integrated and analyzed to derive the spatial distribution of the potential recharge. This approach was used to classify the Haouz Plain (Morocco) into three different zones with respect to the recharge rate, with recharge rates ranging from 3.5 to 18.2 %.  相似文献   

Investigation of the probable wastewater infiltration and its impact on groundwater quality by electrical resistivity tomography and hydrochemistry: a case study of the Pleistocene aquifer at El Sadat city,Egypt     

Abeer A. Kenawy  Usama Massoud  El-Said A. Ragab  Heba M. El-Kosery 《Environmental Earth Sciences》2016,75(3):194

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Pollution assessment of arsenic and other selected elements in the groundwater and soil of the Gulf of Aqaba,Saudi Arabia     

Habes Ghrefat  Mahmoud El Waheidi  Awni Batayneh  Yousef Nazzal  Taisser Zumlot  Saad Mogren 《Environmental Earth Sciences》2016,75(3):229

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