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381.
382.
Samira Adil Mohammed Bouabdellah Fidel Grandia Esteve Cardellach Àngel Canals 《Comptes Rendus Geoscience》2004,336(14):1265-1272
The Bou-Dahar PbZn Mississippi Valley deposits located in the eastern part of the High Atlas Range (Morocco) are hosted by a Liassic reefal complex. Fluid inclusion and ‘crush-leach’ data show that two distinct fluids were involved in the mineralisation deposition: a warmer, more saline fluid (180?°C, NaCl equivalent) and a cooler, less saline fluid (70?°C, 16 wt% equivalent NaCl). Mixing of these two fluids resulted in the precipitation of the ore. The solute composition of the ore-forming brine suggests that the MVT mineralising fluids were probably a mixture of halite-dissolution fluids and evaporated seawater. To cite this article: S. Adil et al., C. R. Geoscience 336 (2004). 相似文献
383.
Nour-Eddine Laftouhi Marnik Vanclooster Mohammed Jalal Omar Witam Mohamed Aboufirassi Mohamed Bahir Étienne Persoons 《Comptes Rendus Geoscience》2003,335(3):307-317
The Essaouira Basin (Morocco) contains a multi-layered aquifer situated in fractured and karstic materials from the Middle and Upper Cretaceous (the Cenomanian, Turonian and Senonian). Water percolates through the limestone and dolomite formations of the Turonian stage either through the marls and calcareous marls of the Cenomanian or through the calcareous marly materials of the Senonian. The aquifer system may be interconnected since the marl layer separating the Turonian, Cenomanian and Senonian aquifers is thin or intensively fractured. In that case, the water is transported through a network of fractures and stratification joints. This paper describes the extent of the nitrate pollution in the area and its origin. Most of the wells and drillholes located in the Kourimat perimeter are contaminated by nitrates with some concentrations over . Nitrate contamination is also observed in the surface water of the Qsob River, which constitutes the natural outlet of the multi-layered complex aquifer system. In this area, agriculture is more developed than in the rest of the Essaouira Basin. Diffuse pollution of the karstic groundwater body by agricultural fertiliser residues may therefore partially explain the observed nitrate pollution. However, point pollution around the wells, springs and drillholes from human wastewater, livestock faeces and the mineralisation of organic debris close to the Muslim cemeteries cannot be excluded. 相似文献
384.
H. A. Al Darwish E. A. Abd El-Gawad F. H. Mohammed M. M. Lotfy 《Environmental Geology》2005,48(4-5):531-542
Fifteen stations (st) were selected along Dubai coastal region to delineate the distribution and the source of total petroleum
hydrocarbon (TPH), total organic carbon (TOC), total Kjeldhal nitrogen (TKN), polycyclic aromatic hydrocarbon (PAHs) and polychlorinated
biphenyls. The concentrations of TPH fluctuated between 2 μg g −1 and 48018 μg g −1 and the values of TOC were in the range of 0.16–5.9 wt%, while TPAHs ranged from 0.09 μg g −1 to 161.72 μg g −1. On the other hand, TPCBs showed values between 0.8 μg kg−1 and 93.3 μg kg−1 and TKN values varied from 218 μg g−1 to 2457 μg g −1. Distribution of oil and organic compounds in Dubai sediments are safe compared with previous studies except for limited
areas at the northeastern offshore. These readings are probably due to: (1) presence of commercial or industrial ports, dry
docks and fishing harbours and (2) population centers mainly concentrated at the northern part of the study area. Results
indicate that TOC can be used as indicator of oil pollution only in heavily oiled sediments. The highest values of TOC, TPH,
TPAHs and TPCBs corresponded to the stations covered with fine sand, due to adsorption properties and larger surface area.
The evaporation of low boiling point compounds from surface layers led to enrichment of sediments with the thick residual.
Al-Hamriya St 3 exhibited the highest values of TPH, TOC, TPAHs and TPCBs and the second highest value of TKN. 相似文献
385.
Ahmed Makaoui Abdelattif Orbi Karim Hilmi Soukaina Zizah Jamila Larissi Mohammed Talbi 《Comptes Rendus Geoscience》2005,337(16):1518
The pelagic ecosystem of the Moroccan Atlantic coast is influenced by the spatiotemporal variability of upwelling. The changes in the physicochemical and biological parameters as well as their interrelationship and regrouping by the principal components analysis allowed us to subdivide the Atlantic coast in four active areas: two areas located at the north of Cape Juby (28°N), characterised by a summery activity and two areas located at the south, active permanently, with a variable intensity. To cite this article: A. Makaoui et al., C. R. Geoscience 337 (2005). 相似文献
386.
387.
The shrinkage of the Lisan Lake (LL) to form the recent Dead Sea (DS) was mainly a result of the reduction of the catchment
area from around 157,000 km2 during Late Pleistocene to 43,000 km2 presently. The reduction in the catchment area resulted from the eruption and spread of the basalt flows of Jabal Arab-Druz
(JAD), which together with the resulting deposition of thick rock debris and gravels occupied the drainage system. The filling
of the pre-basalt drainage system, which used to feed the Dead Sea, with basalts and alluvial sediments blocked the inflows
from reaching the Dead Sea. Local base levels along the basalt flow boarders such as Azraq Oasis, Sirhan Basin and Damascus
Oasis, and numerous pools and mud flats were created. 相似文献
388.
The three towns of Khartoum, Omdurman and Khartoum are located north of the capital of Sudan. This capital has agglomerated to reach more than 7 million inhabitants. The present situation is confronted with a dramatic shortage in freshwater supply. The treatment of surface water from the Nile became costly, particularly in flood season. Thus the authorities turned towards developing groundwater resources. The electric tomography, obtained by the combination of Vertical Electrical Sounding (VES) and well logs, turned out to be very efficient to provide a complete electrical image of the underground from the surface until about 200-m depth. This methodology constitutes a very cheap guide for the evaluation of the quality of groundwater resources in the Khartoum area. To cite this article: M.T. Hussein, H.S. Awad, C. R. Geoscience 338 (2006). 相似文献
389.
Azzouz Kchikach Pierre Andrieux Mohammed Jaffal Mostafa Amrhar Mohammed Mchichi Baadi Boya Mbarek Amaghzaz Thierry Veyrieras Khadija Iqizou 《Comptes Rendus Geoscience》2006,338(5):289-296
Exploitation of the phosphatic layers in Sidi Chennane deposit (Morocco) collides frequently with problems bound to the existence, in the phosphatic series, of sterile bodies qualified as derangements. Our study shows that these bodies, masked by the Quaternary cover can be mapped using the Time-Domain ElectroMagnetic Soundings method (TDEM). It is based on the acquisition and the interpretation of a series of tests carried out above a visible derangement in an old trench of exploitation and on 2500 TDEM soundings carried out in a virgin area of the deposit. The article concerns to the analysis of the results and of the proceeding for a possible large geophysics survey. To cite this article: A. Kchikach et al., C. R. Geoscience 338 (2006). 相似文献
390.
Pouclet André El Hadi Hassan Álvaro J. Javier Bardintzeff Jacques-Marie Benharref Mohammed Fekkak Abdelilah 《International Journal of Earth Sciences》2018,107(6):2101-2123
International Journal of Earth Sciences - Volcanic activities related to the opening of a Cambrian rift in Morocco were widespread from the Fortunian to the Cambrian Epoch 3. Numerous data are... 相似文献