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1.
Jaloul Bejaoui Salah Bouhlel Ahmed Sellami Ahmed Braham 《Arabian Journal of Geosciences》2014,7(6):2483-2497
The Oued Jebs Pb–Zn–Sr deposit is situated on the south edge of the Mourra Triassic diapir, in the Diapir Zone of the Tunisian Atlas. Tow orebody-type are recognized: (1) lens-chapped orebodies hosted in the Dolomitic cap rock that marks the transition zone between the Triassic gypsum cap rock and the overlaying Late Cretaceous series. Mineralization is composed of epigenetic celestite and minor Pb–Zn sulfides. (2) Vein-type and massive-type orebodies crosscutting the Late Cenomanian and Turonian limestone. Mineralization is composed of high-grade ore ranging from 10 to 25 % combined Pb–Zn. Fluid inclusion data for celestite indicate that deposition took place between 70 and 100 °C, or more cooler conditions as indicated by the presence of single-phase inclusions, from mixed NaCl–CaCl2-bearing brines (12–19 wt% NaCl equiv). For the vein-type and massive-type fluid inclusion, data recorded in sphalerite indicate that sulfide deposition took place between 125 and 130 °C mixed NaCl–CaCl2-bearing brines (10–15 wt% NaCl equiv). At least three dilution and cooling trends are also observed that indicate the involvement of more than one fluid in the Oued Jebs hydrothermal system. The epigenetic character of the ores, the host rock nature and the fluid inclusion together permitted to include the Oued Jebs deposit in the large class of MVT deposits and preciously in the sub-class of MVTs associated with salt diapirs environment. The new discovered Oued Jebs deposit is similar in many aspects to the economic Bou Grine deposit. This may point to significant other potential for economic Pb–Zn concentrations that may be located at depth alongside or above many other unexplored Triassic diapirs in the Diapirs zone of the Tunisian Atlas. 相似文献
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Water Resources - The Mzab Valley is characterized by an arid climate with limited amounts of rainfall. In the context of water scarcity, the Mzab water management system recovers floodwater for... 相似文献
3.
Preparing a seismic hazard model for Switzerland: the view from PEGASOS Expert Group 3 (EG1c) 总被引：1，自引：0，他引：1
The seismic hazard model used in the PEGASOS project for assessing earth-quake hazard at four NPP sites was a composite of four sub-models, each produced by a team of three experts. In this paper, one of these models is described in detail by the authors. A criticism sometimes levelled at probabilistic seismic hazard studies is that the process by which seismic source zones are arrived at is obscure, subjective and inconsistent. Here, we attempt to recount the stages by which the model evolved, and the decisions made along the way. In particular, a macro-to-micro approach was used, in which three main stages can be described. The first was the characterisation of the overall kinematic model, the “big picture” of regional seismogenesis. Secondly, this was refined to a more detailed seismotectonic model. Lastly, this was used as the basis of individual sources, for which parameters can be assessed. Some basic questions had also to be answered about aspects of the approach to modelling to be used: for instance, is spatial smoothing an appropriate tool to apply? Should individual fault sources be modelled in an intraplate environment? Also, the extent to which alternative modelling decisions should be expressed in a logic tree structure has to be considered. 相似文献
4.
Haykel Sellami Isabelle La Jeunesse Sihem Benabdallah Marnik Vanclooster 《水文科学杂志》2013,58(8):1635-1657
AbstractThe SWAT model was tested to simulate the streamflow of two small Mediterranean catchments (the Vène and the Pallas) in southern France. Model calibration and prediction uncertainty were assessed simultaneously by using three different techniques (SUFI-2, GLUE and ParaSol). Initially, a sensitivity analysis was conducted using the LH-OAT method. Subsequent sensitive parameter calibration and SWAT prediction uncertainty were analysed by considering, firstly, deterministic discharge data (assuming no uncertainty in discharge data) and secondly, uncertainty in discharge data through the development of a methodology that accounts explicitly for error in the rating curve (the stage?discharge relationship). To efficiently compare the different uncertainty methods and the effect of the uncertainty of the rating curve on model prediction uncertainty, common criteria were set for the likelihood function, the threshold value and the number of simulations. The results show that model prediction uncertainty is not only case-study specific, but also depends on the selected uncertainty analysis technique. It was also found that the 95% model prediction uncertainty interval is wider and more successful at encompassing the observations when uncertainty in the discharge data is considered explicitly. The latter source of uncertainty adds additional uncertainty to the total model prediction uncertainty.
Editor D. Koutsoyiannis; Associate editor D. GertenCitation Sellami, H., La Jeunesse, I., Benabdallah, S., and Vanclooster, M., 2013. Parameter and rating curve uncertainty propagation analysis of the SWAT model for two small Mediterranean watersheds. Hydrological Sciences Journal, 58 (8), 1635?1657. 相似文献
5.
Ben Ameur W Ben Hassine S Eljarrat E El Megdiche Y Trabelsi S Hammami B Barceló D Driss MR 《Marine environmental research》2011,72(5):258-264
Concentrations of ten polybrominated diphenyl ethers (PBDEs) and eight methoxylated polybrominated diphenyl ethers (MeO-PBDEs) in mullet (Mugil cephalus) and sea bass (Dicentrarchus labrax) collected from the Bizerte Lagoon and the Mediterranean Sea were investigated. To the best of our knowledge, this is the first report of these compounds in marine fishes from Tunisia. The PBDE mean concentrations in fish from Bizerte Lagoon were 45.3 and 96.2 ng g(-1) lw respectively in mullet and sea bass, while the concentrations of these compounds in mullet and sea bass from Mediterranean Sea were 7.80 and 27.9 ng g(-1) lw respectively. MeO-PBDE concentrations in mullet and sea bass from Bizerte Lagoon ranged from 6.46 to 286 ng g(-1) lw and from 49.4 to 798 ng g(-1) lw respectively, while the concentrations of these compounds in mullet and sea bass from Mediterranean Sea ranged from 190 to 401 ng g(-1) lw and from 353 to 578 ng g(-1) lw respectively. The total PBDEs and total MeO-PBDEs concentration in fish from Bizerte Lagoon were similar or slightly lower than those reported for other species from other locations around the world. 相似文献
6.
Jaloul Bejaoui Mohamed Samaali Souad Baccouche Nafaa Regugui Mohamed Fethi Ben Hamouda Zohra Azzouz Adel Trabelsi Salah Bouhlel Boulamia Salim 《Arabian Journal of Geosciences》2013,6(7):2685-2689
In this study we investigate the radiological hazard of naturally occurring radioactive material in Tunisian and Algerian phosphorite deposits. Eight samples of phosphorite were collected from the phosphorite mines. The Tunisian and Algerian phosphorites occur in the Late Paleocene and Lower Eocene (Ypresian-Lutetian) in age (Béji Sassi 1984 and Zaïer 1999). Activity concentrations in all the samples were measured by alpha spectrometry and gamma spectrometry. Alpha spectrometry analyses show that the specific activity values of 238U, 234U and 235U in the samples of Tunisian phosphorite were 327?±?7 (321–327), 326?±?6 (325–331) and 14.50?±?0.72 (13.90–15.57) Bq kg?1, respectively. Specific activity measured by gamma spectrometry in the samples of the Tunisian and Algerian phosphorite shows a small difference. Specific activity levels of 40K, 226Ra, 232Th, 235U and 238U in the phosphorite samples from Tunisia were, respectively, 71.10?±?3.80, 391.54?±?9.39, 60.38?±?3.74, 12.72?±?0.54 and 527.42?±?49.57 Bq kg?1 and Algeria were 15.72?±?1.73, 989.65?±?12.52, 12.08?±?1.20, 47.50?±?1.52 and 1,148.78?±?7.30 Bq kg?1, respectively. The measured value of specific activity of 232Th and 40K in the Tunisian phosphorite samples is relatively higher than that found in the samples of Algerian phosphorite. The measured activity of uranium (238U) in the Tunisian phosphorite (527?±?49) Bq kg?1 is lower than in Algerian phosphorite. The measured activity of 238U in the Tunisian phosphorite samples was (527–1,315?±?65) 238U Bq kg?1 which is higher than its maximum background value of 110 Bq kg?1 in soils of the various countries of the world (Tufail et al. Radiat Meas 41:443–451, 2006). Different geological origins of phosphorites deposits are the main reason for the large spread in worldwide specific activities. The obtained results of uranium concentrations in phosphorites of different types (Algerian and Tunisian) demonstrate that the uranium concentrations are mainly governed by the phosphatic material. The present study reveals that phosphorite deposits contain natural radioactivity higher than background level. 相似文献
7.
Zaagane Mansour Refas Soraya Khaldi Abdelkader Frédéric Donzé Hamimed Abderahmane Safa Aissa Moussa Kacem Sebbane Abbes Azzaz Habib Mouassa Souad 《Arabian Journal of Geosciences》2016,9(14):638
The Ouarsenis area is one of the most developed karstic systems of Algeria. It is a karst reservoir drinking water with a population of more than 50,000 people taking fully benefit from it. To understand the development of this karstic system, the local tectonic history of the four main mountain ranges of this culminating area (Ouarsenis) has been analyzed. Although previously identified primarily Cenozoic tectonic activities have been observed, a set of NW-SE joints intersecting the Jurassic limestone has been associated to a post-nappes tectonic events. Moreover, numerous joint sets oriented NNE/SSW have been identified almost over the entire culminating area. These joints are the direct consequence of the following stress history: (i) a NW/SE shortening responsible for a major overlap and the first fold (P1) phase, (ii) a second NNE/SSW shortening stage responsible for the second folding (P2) phase associated with 70° N sinistral strike-slip trend, (iii) a WNW/ESE extension phase resulting from the change of σ 3 stress vertical axis, and (iv) a shearing stress creating a 120° N sinistral strike-slip fault. Only the late phases are responsible of the development of joints, which have been karstified later on. Indeed, significant families of karstified joints, i.e., 20° and 70° N have been found. These joints are related to the extensional and shearing modes, respectively, and linked to a particular in situ karstogenesis. Moreover, this study suggests an ancient establishment of the karstic systems in the Ouarsenis region in at least two stages: pre-figured and activated behaviors during the Cenozoic. 相似文献
8.
Souad Boubekraoui Michel Courteaud Maurice Aubert Yves Albouy Jean Coudray 《Journal of Applied Geophysics》1998,40(4):165-177
In order to investigate aquifers, several geophysical surveys have been carried out in the Baril area of the southern flank of Piton de la Fournaise volcano on Reunion in the Indian Ocean using audiomagnetotelluric (AMT), very-low-frequency (VLF) and self-potential (SP) methods. We present the results with emphasis on a comparison between SP data and the findings of geoelectric surveys. AMT soundings have indicated, from the surface downward, three layers: (i) resistive volcanic rocks, (ii) an intermediate resistivity layer, and (iii) a conductive basement attributed to a seawater-bearing aquifer. VLF measurements allow the mapping of the first layer apparent resistivity, and therefore its bottom, when the true resistivity is supposed to be isotropic and homogenous. When this assumption does not hold, only the SP method permits the mapping of this bottom. Because of the good agreement between the SP and electromagnetic results, we propose the SP method as the first tool that should be used in studying shallow hydrogeological structures in volcanic areas. 相似文献
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10.
Amel Dhib Mounir Ben Brahim Boutheina Ziadi Fourat Akrout Souad Turki Lotfi Aleya 《Marine pollution bulletin》2013
We studied the distribution of planktonic and epiphytic ciliates coupled with environmental factors and microalgae abundance at five stations in Ghar El Melh Lagoon (Tunisia). Planktonic ciliates were monitored for a year and epiphytic ciliates were sampled during summer 2011 in concordance with the proliferation of the seagrass Ruppia cirrhosa. Ciliate assemblage was largely dominated by Spirotrichea followed respectively by Tintinnida of and Strombidiida. No significant difference was found in the distribution of ciliate species among the stations. Redundancy analysis indicates that abiotic factors (temperature and nutriments) have a significant effect on the dynamics of certain ciliates. For epiphytic ciliates, 4 species were identified: Tintinnopsis campanula, Aspidisca sp., Strombidium acutum and Amphorides amphora. Based on PERMANOVA analyses, ciliates exhibit significant correlations among months and stations. According to ACP, epiphyte distribution follows roughly those of R. cirrhosa and pH. Significant correlations were found between harmful dinoflagellates and both planktonic and epiphytic ciliates. 相似文献