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1.
Analysis and integration of geological/metallogenic data and digitally processed gravimetric/aeromagnetic data to the oriental Saharan Atlas domain were carried out to understand the spatial distribution and structural control on Pb-Zn (Ba) deposits of the oriental Saharan Atlas. The use of this combined technique suggests that most of mineral deposits appear to be regionally controlled by structural trends (subparallel NE-SW-trending) along margins of subsiding sedimentary basins. Mineralization occurs along or near major NE-SW-trending faults, locally intersected by NW-SE-trending faults. In addition, mineral deposits are usually either inside anticlinal hinge zones (example, Merouana, Ichmoul and Ain Mimoum ore deposits) or on the flanks of anticlinal structures (example, Ain Bougda ore deposit). In “diapiric zone”, mineral deposits are generally located on diapiric structures borders (peridiapiric concentrations), related to NE-SW/NE-SW and E-W-trending faults. Other mineral concentrations occurs along the margins of tectonic troughs zones (example, Morsott trough) resulting probably by NW-SE-trending deep faults movement. In summary, our research suggested that regional parameters, such as NE-SW/NW-SE-trending lineaments, intersections of these lineament zones and margins of subsiding sedimentary basins/diapiric structures, serve as significant indicators and provides a valuable framework for guiding the early stages of Pb-Zn (Ba) mineral exploration; other considerations must then be applied in this region, like integration of surficial geochemical anomalies that allows better delineation of targets for further mineral exploration.  相似文献   
2.
Geotechnical and Geological Engineering - This paper presents a study on Chlef sand to examine the effect of fines content (Fc), relative density (RD) and initial conditions on the compressibility...  相似文献   
3.
Water resources in Algeria are mainly controlled by climate change which creates enormous problems in its planning, management and distribution. While the surface water resources are perfectly managed and operated by means of dams and small dams built for several years, the groundwater resources remain long unknown and unusable because of the lack of relevant working tools (e.g., methods, formulas, maps, etc.) for planners and engineers working in the field of water resources exploration. To highlight the hydrodynamic processes of groundwater in shallow aquifers of the basins of northern Algeria, we conducted a study using 81 subwatersheds collected from different locations at the basins; taking into account the climatic and geomorphological factors, to understand water usage trends, analyse patterns, tap good shallow aquifers and ensure long lasting supplies of water through arid periods, mapping and modelling of groundwater are fundamental to problem resolution. Multivariate statistical techniques as well as cluster and principal component analysis were applied to the data on groundwater flow, with the objective of defining the main controls on the groundwater flows at the basins. These statistical techniques showed the presence of three groundwater flow groups with increasing importance according to precipitation. The first group was mainly influenced by climatic factors, the second was more controlled by the communication between the surface and underground flows and the third group revealed the influence of geomorphological factors on groundwater flows.  相似文献   
4.
Building frequencies (fundamental and higher modes) are a critical parameter especially in the field of structural health monitoring mainly based on the stability of the structural dynamic parameters of individual building (frequencies, damping and modes shape). One of the most used methods to find out these parameters is based on the use on ambient vibration analysis. In this work, we study the fluctuations over a month period of the fundamental frequencies (transverse and longitudinal) of a 3.5-story RC-building made of 2 identical units connected by a structural joint. Time independent building frequencies is a strong assumption; as illustrated by our experiment showing that over an observation period of a month, building frequencies fluctuate of about 3.5 %. A clear correlation is found between the building frequency fluctuations and temperature variations, with a phase-shift interpreted as the characteristic time of heat diffusion within the walls. This allows: (1) determining the thermal diffusivity of the structure, (2) inferring its relative stiffness variations, and (3) showing that its Young modulus varies linearly with temperature.  相似文献   
5.
The diapiric province of north-eastern Algeria and Tunisia extends NE–SW over several hundreds of kilometres. Available, geophysical and geological investigations were focused on the study of known diapiric outcrop. In contrast to the existing work, our study is focused on to identify a new hidden near surface salt diapir in the Guelma Basin, north-east of Algeria.Integrated geophysical study comprising aeromagnetic, gravimetric and DC resistivity data calibrated with existing well information provides new insights into the geometry of the geologic structure of Guelma Basin. Spatial correlation between magnetic low, strong gravity minimum and resistivity high reveal a hidden near surface salt diapir. The Guelma salt diapir is topped by a local topographic high which follows exactly the underlying salt body. Joint gravity-magnetic modelling indicates that salt is deeply rooted and has a dome-like shape. The Guelma salt diapir was triggered by normal faulting and is directly controlled by regional extension.  相似文献   
6.
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7.
On March 20, 2006, an earthquake (M w = 5.3; SED) struck the mountainous region of the Babors chain (Wilaya of Bejaia, northeast Algeria). The seismic epicenter was located near the Kherrata village. This earthquake was felt on a large area of the northeastern part of Algeria. It reached an intensity of VII (EMS scale) at the Laalam village, situated at about 20 km northeast of Kherrata. Here, many old and recent houses were damaged or collapsed totally, four people died and 68 were injured. Field investigations revealed that these casualties were caused by a landslide triggered by the earthquake. Many fissures were visible on ground throughout the site. They were generated by both sliding and settling phenomena. The Laalam site is prone to landslide, as revealed by some evidences on old instabilities. This is due to two main factors: local geomorphology and geology. These factors intervene synchronously for reducing the slope instability at the Laalam village. The March 20, 2006 Kherrata earthquake was the trigger that released the Laalam landslide.  相似文献   
8.
Results from geophysical investigations (electrical resistivity, electromagnetic mapping and seismic refraction) on an excavated cell of the Ouled Fayet (Algiers, Algeria) pilot landfill indicated the presence of an underground runoff and permeable soil underneath the cell. These results contradict those obtained by a feasibility study, based, however, only on the analysis of seventy-six 10-m drilling cores. The 1D boreholes information has been proven to be insufficient and to give biased results. The presence of water at depth is evidenced by lower resistivity, high conductivity anomalies and increase of P-wave velocity. Thus, to the contrary of what is claimed in the feasibility study, a threat of leachate pollution is real. This study shows that landfill construction studies cannot give trustful results without geophysical investigations. More specifically, in Algeria, it is imperative to elaborate a landfill construction code, which should include mandatory geophysical prospecting and deeper drilling cores.  相似文献   
9.
In this work, we present results of the hydrogeochemical and isotopic studies on groundwater samples from the El Ma El Abiod Sandstone aquifer, in Tébessa, Algeria. Chemical and environmental isotope data are presented and discussed in order to identify the geochemical processes and their relation with groundwater quality as well as to get an insight into the hydrochemical evaluation, in space and time, of groundwater and of the origin of dissolved species. A combined hydrogeologic and isotopic investigation have been carried out using chemical and isotopic data to deduce a hydrochemical evaluation of the aquifer system based on the ionic constituents, water types, hydrochemical facies, and factors controlling groundwater quality. All of the investigated groundwaters are categorized into two chemical types: low mineralized water type and relatively high mineralized water type. Interpretation of chemical data, based on thermodynamic calculations and geochemical reaction models of selected water groups constructed using PHREEQC, suggest that the chemical evolution of groundwater is primarily controlled by water–rock interactions, involving (1) acidic weathering of aluminosilicates, (2) dissolution of secondary carbonate minerals, and (3) cation exchange of Na+ for Ca2+. However, the original composition of groundwater may have been modified by further secondary processes such as mixing of chemically different water masses. The combined use of SI and mass-balance modeling has shown to be a useful approach in interpreting groundwater hydrochemistry in an area where large uncertainties exist in the understanding of the groundwater flow system. Interpretation of 18O and 2H, suggest that the recharge of the investigated groundwaters may result from different mechanisms.  相似文献   
10.
The original version of this paper was published with incomplete affiliation. Given in this article are the complete affiliations.  相似文献   
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