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1.
This study focuses on the hydrochemical characteristics of 47 water samples collected from thermal and cold springs that emerge from the Hammam Righa geothermal field, located in north-central Algeria. The aquifer that feeds these springs is mainly situated in the deeply fractured Jurassic limestone and dolomite of the Zaccar Mount. Measured discharge temperatures of the cold waters range from 16.0 to 26.5 °C and the hot waters from 32.1 to 68.2 °C. All waters exhibited a near-neutral pH of 6.0–7.6. The thermal waters had a high total dissolved solids (TDS) content of up to 2527 mg/l, while the TDS for cold waters was 659.0–852.0 mg/l. Chemical analyses suggest that two main types of water exist: hot waters in the upflow area of the Ca–Na–SO4 type (Hammam Righa) and cold waters in the recharge zone of the Ca–Na–HCO3 type (Zaccar Mount). Reservoir temperatures were estimated using silica geothermometers and fluid/mineral equilibria at 78, 92, and 95 °C for HR4, HR2, and HR1, respectively. Stable isotopic analyses of the δ18O and δD composition of the waters suggest that the thermal waters of Hammam Righa are of meteoric origin. We conclude that meteoric recharge infiltrates through the fractured dolomitic limestones of the Zaccar Mount and is conductively heated at a depth of 2.1–2.2 km. The hot waters then interact at depth with Triassic evaporites located in the hydrothermal conduit (fault), giving rise to the Ca–Na–SO4 water type. As they ascend to the surface, the thermal waters mix with shallower Mg-rich groundwater, resulting in waters that plot in the immature water field in the Na–K–Mg diagram. The mixing trend between cold groundwaters from the recharge zone area (Zaccar Mount) and hot waters in the upflow area (Hammam Righa) is apparent via a chloride-enthalpy diagram that shows a mixing ratio of 22.6 < R < 29.2 %. We summarize these results with a geothermal conceptual model of the Hammam Righa geothermal field.  相似文献   
2.
To some extent, the sedimentary sequence with the largest groundwater reserves in northern Sahara is marked by a certain water table level, regionally known as the "Continental Intercalaire"(CI). "Continental Intercalaire"(CI) refers to "Continental Intercalary" widely distributed among three countries. Algeria, Tunisia and Libya, which have significant potential of water resources. As it is the only water resource relatively easily accessible to the inhabitants of the Sahara, it is widely developed. The physico-chemical characteristics of statistical processing in principal component analysis(PCA) and the chemical phase measurement of groundwater in the unconfined aquifer captured by "Foggaras"(traditional system irrigation composed of well system linked by a horizontal channel from their bases) and the deep drillings located in the study area were accessible. Therefore, there were some favorable conditions for comparing the chemistry of these waters with the standards of potability established by the World Health Organization. Then, the study detected the origin of excessive mineralization and the excessive content of Na, Cl, K, Mg and Ca that originated from the leaching of the clay and carbonate layers of the "Continental Intercalaire". In addition, the enrichment in NO_2~-, NO_3~- and SO_4~(2-) was due to the excessive use of fertilizer in the whole region for shallower Foggaras waters, and this study also showed the dominant chemical facies of groundwater related to the significant abundance of these mineral salts in this thick aquifer horizon.  相似文献   
3.
Regions of Agane and Gouérarate represent an ancient fragment of ophiolitic suture localized in the axial area of the Mauritanides Belt. These two regions are characterized by the abundance of completely serpentinized formations. In this study, we present the first use of Raman spectroscopy for identifying the species of serpentine present in the Mauritanides Belt. Serpentinites of Agane are derived from refractory peridotites composed of dunites–harzburgites; however, there are also rare serpentinites derived from ultramafic cumulates. Antigorite represents the dominant species in the serpentinite. Furthermore, chrysotile is found as post-antigorite veins. These veins are post-obduction and mark the final phase of serpentinization. The abundance of antigorite and the absence of lizardite confirm that subduction was the environment of serpentinization in these two regions, and that “the oceanic opening” responsible for the formation of ophiolitic sutures in the Mauritanides Belt was limited. The term “serpentinite” is no longer applicable to the formations of Gouérarate. As a result, these formations correspond to old serpentinites transformed to birbirites which are in phase of transformation into laterites.  相似文献   
4.
The authors presented indoor practice experiments of parameters affect on foaming and foam stability. Experiments were carried out and special equipments were used to determine foaming and foam stability; tests were tabulated and charted. The effects of chemical and physical parameters on foaming and foam stability have been conducted.  相似文献   
5.
Geotechnical and Geological Engineering - The improvement of salt affected lands is a major environmental challenge in arid and semi arid regions all over the world. Electrokinetic treatment is one...  相似文献   
6.
Parameters affect foaming and foam stability during foam drilling   总被引:1,自引:0,他引:1  
The authors presented indoor practice experiments of parameters affect on foaming and foam stability. Experiments were carried out and special equipments were used to determine foaming and foam stability; tests were tabulated and charted. The effects of chemical and physical parameters on foaming and foam stability have been conducted.  相似文献   
7.
The imbrication’s area in northern Tunisia is the most external segment of Alpine range, where several associated folds types with thrust ramps are recognized within imbricate units beneath Numidian front slope. Their presence help to understand thrusting mechanisms installation through studied area. In fact, this zone was considered as a result of Paleogene gravitary slop (Kujawski (Ann Miner Géol Tunis (24):281, 1969); Caire (Ann Min Géol Tunis 26:87–110, 1973); Rouvier 1977), which is proved to be affected by major deep decollement, given rise to various structures, some are propagation folds, specific of foreland front, limited to this area, and those in more external position: Tunisian Atlas (Creusot et al. (C R Acad Sci Paris 314(Sér II):961–965, 1992); Ouali and Mercier (PII: S0191-8141(97):00048-5, 1997); Ouali 1984; Ahmadi et al. (J Struct Geol 28:721–728, 2006)). Various categories of fold ramps could be identified: frontal folds ramp NE–SW and others as lateral or oblique ramp with NW–SE trend (Aridhi et al. (C R Geosci 343:360–369, 2011)). The relation between various structures has been used as recognition tools of thrusting sequences and to propose a new deformation chronology. Delimited outcropping of these structures between two both parallel faults strikes with regional displacement, leads to interpret these faults as cogenetic tear faults of propagation thrusts; this fault separates two domains with different deformation styles from each other side.  相似文献   
8.
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   
9.
This research presents experimental data on mechanical foam bursting device,based on the high speed of air fluid impinging insidethe foam bursting device,foam bubbles disrupted as a consequence of pressures changed very quickly as shear force and their impact forces.Experimental data on foam-bursting capacity have been presented.Designed device can provide effective foam bursting on collapse foam.  相似文献   
10.
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