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1.
This paper reports the data on the structure of the northwestern boundary of the Middle Amur sedimentary basin which were obtained after resumption of audiomagnetotelluric soundings. The geoelectric sections for two profiles across the basin strike are constructed, the sedimentary cover and basement structures are studied, and their electrical properties are determined. The compared data of the earlier and present studies show low-resistivity zones of 50–150 Ohm m beneath high-resistivity rocks of 500–1000 Ohm m in the northwestern part of the Ul’dura–Churki uplift at a 2–4 km depth, which are absent in the southwestern part of the uplift. This fact is related to strike-slip–overthrust processes due to graben formation in the area of junction with the Jiamusi–Bureya Massif in the Kur fault zone (YYilan–Yitong branch of the Tan-Lu fault zone) and also to global left-lateral strike-slip displacements and volcanic activity.  相似文献   

2.
Groundwater is a very important component of water resources in coastal aquifers in Thoothukudi. It has been established that the groundwaters in the coastal zone of the Zirconium Complex, Pazhayakayal, Thoothukudi district, Tamilnadu, India, are subjected to wave and tidal impact. The groundwater quality was studied by hydrogeological methods, 2D electrical resistivity imaging (ERI) techniques (six profiles), 11 Wenner vertical electrical sounding (VES), and well log analysis. Also, nine geochemical water samples were taken from the study area. The 2D ERI and VES surveys were carried out using WGMD-4 Ltd., Chennai, resistivity meter, multicore cable, and multielectrodes with Wenner array. The collected resistivity data were interpreted using the Res2DINV software. The research shows that the groundwaters are the result of the paleoriver flow along the Tamirabarani Channel in the western area and of the seawater intrusion in the eastern area. The fresh water is characterized by resistivity of about 10–100 Ohm?m in the study area. The resistivity of 10–50 Ohm?m indicates that the subsurface section is made up of sand, clay, and caliche. Resistivity values of more than 200 Ohm?m are specific to sand dunes. The very low resistivity (<5 Ohm?m) layer might be due to the seawater intrusion in the study area. Six water samples from the well drilled in the coastal area were analyzed, which made it possible to determine the concentrations of major and trace elements in the groundwaters. These data were used to establish the seawater intrusion and coastal environment characteristics in the study area.  相似文献   

3.
The Zeya-Bureya Basin is a part of the East Asian intracontinental riftogenic belt, which includes oil-and-gas bearing and Mesozoic-Cenozoic sedimentary basins perspective for oil and gas (Upper Zeya, Songliao, Liaohe, North Chinese). The basins are characterized by certain geophysical features: reduced thickness of the Earth’s crust and lithosphere, a higher thermal flow and a raised roof of the asthenosphere. The Zeya-Bureya Basin is composed of Mesozoic-Cenozoic sedimentary-volcanic units, with respect to which the deep structure data are absent. In 2010, geoelectric studies were carried out in this territory using the method of magnetotelluric sounding along the profile Blagoveshchensk-Birokan. These works yielded geoelectric sections down to 2 and 200 km depth. The sedimentary cover is characterized by electric resistivity of 20–50 Ohm m and by thickness of 1700 m. In the section, the Khingan-Olonoi volcanogenic trough is distinct for resistivity of 200–300 Ohm m at a background of 500–1000 Ohm m of the basement rocks. The Zeya-Bureya Basin, in terms of its geophysical characteristics, differs from oil-and-gas bearing basins of the riftogenic belt (thickness of the lithosphere is increased up to 120 km, thermal flow is low, 40–47 mW/m2). The structure of mantle underplating is explicitly seen in the section. The geophysical characteristics close to those of the Zeya-Bureya Depression are typical for gold-bearing structures of the Lower Amur ore district. Nevertheless, manifestations of oil-and-gas bearing potential in particular grabens are possible.  相似文献   

4.
This study has been conducted to find out the aquifer characteristics of Bagerhat Sadar and adjacent areas in Bangladesh using geoelectrical resistivity method and borehole logs. The interpretation of resistivity soundings (14 nos.) shows that the sub-surface lithological sequence can be divided into four geoelectric units. The deepest geoelectric unit (with resistivity from 8 Ohm-m to 18 Ohm-m) represents the deep aquifer with usually fresh water. Resistivity values of 12 ?m or more for this unit may indicate formation water as acceptable for coastal people. In the study area, the shallow aquifer inferred is not suitable for groundwater development.  相似文献   

5.
Investigation for high yielding water wells in the khondalitic terrain (graneti ferrous silliminite gnesiss) is mostly faced with the problem of identification of the extent of the depth of kaolinisation of the aquifer. The traditional Vertical Electrical Sounding survey, Seismic Refraction survey and Very Low Frequency Electromagnetic survey could not identify the kaolinisation of the aquifer in the present investigations. The Two Dimensional (2D) Resistivity and Induced Polarization (IP) Imaging surveys are attempted for the identification of kaolinised layer and depth of kaolinisation. Number of 2D Resistivity and IP Imaging profiles were conducted near Chipurupally in Vizianagaram district of Andhra Pradesh, India along successful and failed wells located within short distances. Resistivity and IP measurements were carried out using an ABEM SAS 4000 Terrameter. The resistivity and I.P. images have provided a clear view of the thickness of the highly weathered zone (kaolinised zone) at both successful and failed wells. The highly weathered zone is identified with the resistivity values below 25 ohm.m. The depth of highly weathered material at failed well is extended about 8–10 m more deeper than the successful wells at some places to as much as 20 m more deep at some other places. This extended deeper kaolinisation of the aquifer is responsible for failure of wells. Layers having resistivities between 25–65 Ohm.m are identified as aquifer layers which are composed of moderately weathered and fractured khondalitic suit of rocks (Garnti ferrous sillimanite/biotite gneiss). Layers with resistivities greater than 65 Ohm.m are interpreted to have basement characteristics belonging to the granite gneiss. Interestingly IP imaging has not provided any greater insights in delineating the kaolinistion of the aquifer when compared to resistivity Imaging, in fact resitivity imaging has shown greater depths of kaolinisation than IP Imaging.  相似文献   

6.
The Quaternary aquifer of Wadi Ham, UAE has been overexploited during the last two decades to meet the increasing water demands. As a result, the dynamic balance between freshwater and seawater has been disturbed and the quality of the groundwater has deteriorated. In this paper, a 2D earth resistivity survey was conducted in Wadi Ham in the area between Fujairah and Kalba to delineate the seawater intrusion. Existing monitoring wells were used to measure the horizontal and vertical variations in water salinity and thus to improve the interpretation of earth resistivity imaging data. Results of vertical electrical soundings and chemical analyses of collected water samples were used to obtain an empirical relationship between the inferred earth resistivity and the amount of total dissolved solids. This relationship was used along with the true resistivity sections resulting from the inversion of 2D resistivity data to identify three zones of water-bearing formation (fresh, brackish, and salt-water zones). Along the four 2D resistivity profiles, the depth to the fresh-brackish interface exceeded 50 m at the western part of the area and was in the order of 10 m or less in the eastern side near the shoreline. Depth to the brackish-saline water interface reached about 70 m in the western side and was in the order of 20 m in the eastern side. The thickness of the fresh water zone decreases considerably in the farming areas toward Kalba and thus the degree of seawater intrusion increases.  相似文献   

7.
 A geophysical survey was conducted to determine the depth of the base of the water-table aquifer in the southern part of Jackson Hole, Wyoming, USA. Audio-magnetotellurics (AMT) measurements at 77 sites in the study area yielded electrical-resistivity logs of the subsurface, and these were used to infer lithologic changes with depth. A 100–600 ohm-m geoelectric layer, designated the Jackson aquifer, was used to represent surficial saturated, unconsolidated deposits of Quaternary age. The median depth of the base of the Jackson aquifer is estimated to be 200 ft (61 m), based on 62 sites that had sufficient resistivity data. AMT-measured values were kriged to predict the depth to the base of the aquifer throughout the southern part of Jackson Hole. Contour maps of the kriging predictions indicate that the depth of the base of the Jackson aquifer is shallow in the central part of the study area near the East and West Gros Ventre Buttes, deeper in the west near the Teton fault system, and shallow at the southern edge of Jackson Hole. Predicted, contoured depths range from 100 ft (30 m) in the south, near the confluences of Spring Creek and Flat Creek with the Snake River, to 700 ft (210 m) in the west, near the town of Wilson, Wyoming. Received, May 1997 · Revised, February 1998 · Accepted, April 1998  相似文献   

8.
The objective of this study was to assess the subsurface strata and groundwater situation of Olomoro, Nigeria using borehole logging and electrical resistivity techniques. The borehole logging consisting of resistivity and spontaneous potential logs were conducted by using the Johnson Keck logger on a drilled well in the study area. The electrical resistivity survey involving 17 vertical electrical soundings (VES) with a maximum current electrode spacing of 100 to 150 m was conducted using the Schlumberger electrode configuration. Analysis of the well cuttings revealed that the lithology of the subsurface consist of topsoil, clay, very fine sand, medium grain sand, coarse sand and very coarse sand. Results of the downhole logging also revealed that the mean electrical conductivity and the total dissolved solid of the groundwater was obtained as 390 μS/cm and 245 mg/cm3 respectively. These values are within the acceptable limit set by the Standard Organization of Nigeria (SON) for drinking water. The result of the vertical electrical sounding interpreted using the computer iterative modeling revealed the presence of four to five geoelectric layers which showed a close correlation with result from the lithology and downhole logging. Results further showed that the resistivity of the subsurface aquifer ranged between 1584 and 5420 Ωm while the aquifer depths varied between 27.8 and 39.3 m. Groundwater development of the area is suggested using the depth and resistivity maps provided in this study.  相似文献   

9.
The Mamora aquifer, in the northern Moroccan Meseta, constitutes the main regional water resource. Its impermeable basement is mostly composed of blue marls. The lithostratigraphy of the basin aquifer is characterised by a sequence of sandstones, sandy limestones, conglomerates and sandy clays.The structure of the basement of the Mamora aquifer, deduced from electrical resistivity measurements, allowed the hydrogeological behaviour of the reservoir, and the direction of the groundwater flow, to be established. The combination of the lithological, morphological, piezometric, geophysical and structural investigations revealed a northward thickening of the substrate with groundwater flow towards the Rharb (to the north) and towards the Atlantic Ocean (northwest). This ‘multicriteria’ approach enabled a structural model to be defined, which correlated well with the aquifer geometry and the groundwater flow. The variability of the hydrogeological units, and the northward thickening of the sedimentary facies, were controlled by northeast-southwest orientated faults, which affect their impermeability.  相似文献   

10.
Electrical resistivity surveying for delineating seawater intrusion was performed in the Dibdibba aquifer in the area between the cities of Al-Zubair–Safwan and Al-Zubair–Umm Qasr in the vicinity of Khor AL-Zubair Channel, Basrah governorate, southern Iraq. Fourteen 2D resistivity profiles with a total length of 14 km were collected in the study area. The resistivity sections were compared with lithological data extracted from 11 boreholes. Thirty-nine groundwater samples were collected within the area and analyzed for chemical constituents; internal hydrogeological reports and unpublished studies were also evaluated. Results reveal the existence of three major resistivity layers, ranging from 0.1 to 130 Ωm at various depths and locations. The first layer has very low electrical resistivity (0.1–5 Ωm) representing a layer saturated with saltwater intruded from Khor AL-Zubair Channel. The second layer shows resistivity in the range of 5–130 Ωm, attributed to a transition zone and an unaffected zone saturated with brackish groundwater. The last resistivity layer (<?3 Ωm) represents coarse-grain sediments saturated with saline groundwater. Furthermore, a hard clay bed (Jojab) appears with a resistivity of 3–7 Ωm in all 2D imaging lines within a depth of 20–28 m. Electrical conductivity (EC) measurements from seven wells collected in 2014 and 2016 show a positive EC difference increasing landward with an average increase of 1927 µS/cm. In addition, six chemical relationships (Na/Cl, [Ca?+?Mg]/[HCO3?+?SO4], SO4/HCO3, SO4/Cl, Mg/Ca and Cl/[HCO3?+?CO3]) are used to detect the source of salinity in groundwater. This study proves that extensive use of high-resolution 2D imaging sections, alongside lithological and hydrogeological data, can serve as a useful tool to delineate the boundaries between aquifers, identify hydraulic boundaries between groundwater with different salinities and allocate hard clay layers between the upper and lower Dibdibba aquifer. In general, the combination of 2D imaging and hydrochemistry enables conceptualization of the hydrogeological situation in the subsurface and characterization of the salinity source, here seawater intrusion, in the study area. There have been no studies published so far on the characteristics of saltwater intrusion in the study area, and this study is considered to be important for monitoring and studying the intrusion and regression of seawater.  相似文献   

11.
As Suqah area is a NW–SE trending wadi present in the west central part of the Arabian Shield. It comprises Precambrian–Cambrian basement rocks, Cretaceous–Tertiary sedimentary succession, Tertiary–Quaternary basaltic lava flows, and Quaternary–Recent alluvial deposits. The magnetic anomalies indicated the presence of many recent local buried faults. These affected the distribution of the clastic sedimentary succession and seem to have controlled the deep groundwater aquifers. Groundwater movement is towards the west and northwest, following in general the surface drainage system. Hydraulic gradient varies greatly from one point to another depending on the pumping rates and cross-sectional area of the aquifer in addition to its transmissivity. The detailed results of the resistivity and seismic measurements were integrated with those obtained from test holes drilled in the study area. Groundwater occurs mainly in two water-bearing horizons, the alluvial deposits and within the clastic sedimentary rocks of Haddat Ash Sham and Ash Shumaysi formations. The shallow zone is characterized with a saturated thickness of 3–20 m and water is found under confined to semi-confined conditions. Water levels were encountered at depths varying from 3 to 16 m in the alluvial wadi deposits and from 18 to 62 m in the sedimentary succession. The combinations of vertical electrical sounding, horizontal electrical profiling, and drilling led to the identification of groundwater resources in the study area. Resistivity soundings clearly identified the nature of the lithological depth and proved useful at identifying water-bearing zones. Significantly, the majority of the groundwater was found within the deep confined aquifer gravelly sandstone, rather than in the shallow unconfined aquifer.  相似文献   

12.
El Bahariya Oasis is a part of the great groundwater reservoir of the Western Desert of Egypt. The different stratigraphic units, the water-bearing zones, aquifer potentiality conditions, and the favorable locations for drilling new wells were evaluated by carrying out 24 Schlumberger vertical electrical soundings (VESs), along with the data of some wells drilled in the near vicinity of the measuring sites. The results of the interpreted field data revealed the presence of ten distinctive subsurface geoelectric layers; a thin surface, dry loose sand and gravel, sandy clay and shale interclations, saturated coarse sand layer, shale and clay, and saturated fine sandstone and saturated coarse sandstone. The aquifer is a multilayer aquifer with different thicknesses represented by the fourth, sixth, eighth, and tenth geoelectric layers. Results also revealed that the thicknesses of the water-bearing horizons increase towards the east direction, consequently the aquifer potentiality increases. Therefore, the best production well locations are in that direction. Depth to water starts from 40 m at VES no. 14 and increases gradually toward the east to reach 66 m at VES no. 5. Hydrogeochemical analysis of two groundwater samples taken from Ein El Ezza and well no. 2 showed that groundwater in the study area is suitable for agricultural purposes but not for human consumption due to the high iron content. Recommendations concerning site selection for drilling new productive groundwater wells are given.  相似文献   

13.
Water resources in the Algerian South are rare and difficult to reach because they are often too deep. This is the case of Guerrara which is characterized by an annual precipitation average of less than 60 mm. The water supply is warranted from groundwater, frequently too deep and badly known. The main purpose of the present study is to determine the geometry of aquifer from geophysical data. Fourteen vertical electrical soundings covering the total surface area were carried out by using an arrangement of electrodes called “Schlumberger array.” The length of the selected transmission line (AB) was 1,000 m, which allowed a vertical investigation reaching up to 160 m of depth. The analysis of the results shows that the prospected zone is characterized by the succession of layers with different electrical resistivities. A sandstone aquifer characterized by resistivities near 100 Ω m overcoming a limestone aquifer stronger with values that exceed 1,000 Ω m, separated by a conductive layer of clay with average resistivity of 15 Ω m. Distribution map of sandstones thickness shows the structural variations of this horizon allowing an estimation of its hydraulic potential.  相似文献   

14.
Understanding deep continental structure and the seismotectonics of Deccan trap covered region has attained greater importance in recent years. For imaging the deep crustal structure, magnetotelluric (MT) investigations have been carried out along three long profiles viz. Guhagarh–Sangole (GS), Sangole–Partur (SP), Edlabad–Khandwa (EK) and one short profile along Nanasi–Mokhad (NM). The results of GS, SP and NM profiles show that the traps lie directly over high resistive basement with thin inter-trappean sediments, where large thickness of sediments, of the order of 1.5–2.0 km, has been delineated along EK profile across Narmada–Son–Lineament zone. The basement is intersected by faults/fractures, which are clearly delineated as narrow steep conducting features at a few locations. The conducting features delineated along SP profile are also seen from the results of aeromagnetic anomalies. Towards the southern part of the profile, these features are spatially correlated with Kurduwadi rift proposed earlier from gravity studies. Apart from the Kurduwadi rift extending to deep crustal levels, the present study indicates additional conductive features in the basement. The variation in the resistivity along GS profile can be attributed to crustal block structure in Koyna region. Similar block structure is also seen along NM profile.Deccan trap thickness, based on various geophysical methods, varies gradually from 1.8 km towards west to 0.3 km towards the east. While this is the general trend, a sharp variation in the thickness of trap is observed near Koyna. The resistivity of the trap is more (150–200 Ω m) towards the west as compared to the east (50–60 Ω m) indicating more compact or denser nature for the basalt towards west. The upper crust is highly resistive (5000–10,000 Ω m), and the lower crust is moderately resistive (500–1000 Ω m). In the present study, seismotectonics of the region is discussed based on the regional geoelectrical structure with lateral variation in the resistivity of the basement and presence of anomalous conductors in the crust.  相似文献   

15.
 One-third of the population of Oman depends upon groundwater extracted from the alluvium of the Batinah Plain, on the coast of the Gulf of Oman. Deep geophysical exploration techniques were used to determine the depth and nature of the alluvium and the boundaries of the aquifer. The base and structural controls of the alluvial basin at its contact with Tertiary marine sediments and Cretaceous ophiolite were mapped with seismic reflection data, recorded originally for oil exploration. The base of the alluvium dips northward from the foothills of the Northern Oman Mountains, reaching a maximum depth of 2000 m at the coast. The varying facies of the alluvium are grossly characterised by different, overlapping ranges of electrical resistivity, depending largely on the clay content and degree of cementation. Resistivities near the coast are reduced by saline intrusion. These variations of resistivity were mapped with time-domain electromagnetic sounding along 400 km of profile, to distinguish among the three zones of the alluvial aquifer. The wedge of saline intrusion was also delineated, up to 10 km from the coast. The thickness of the saturated gravel aquifer ranges from 20–160 m in an area greater than 600 km2. Received, April 1997 · Revised, January 1998 · Accepted, April 1998  相似文献   

16.
The coastal aquifer of the Plio-Quaternary delta sediment deposits of the Vélez river (province of Málaga, Spain) presents a highly irregular basement morphology and widely varying fill thickness (10–80 m between neighbouring sectors). The basin, which is tectonically controlled, is filled with lutite facies alternating with channel-filling rudites. This detrital aquifer is affected by seasonal seawater intrusion–extrusion processes due to increasing withdrawal of groundwater for human consumption and irrigation during dry periods.A study was performed to improve the hydrogeological knowledge of this coastal aquifer system. The study examined the morphology of the impervious substratum, the facies distribution and the position of the seawater wedge. For this purpose, an Electrical Resistivity Tomography (ERT) geophysical technique was used and the tomographic data were calibrated using geological observations and borehole studies. An analysis was carried out to compare the direct information obtained from the 35 boreholes with the indirect data corresponding to the four electrical tomography profiles. In the study, over 9660 resistivity data points were processed.The ERT profiles perfectly corroborated the information derived from the boreholes. The profiles made it possible to detect thickness changes, lithological changes and the presence of faults. Moreover, from a hydrogeologic standpoint, this research technique is capable of detecting the position of the phreatic level and, in coastal aquifers such as the one examined in this study, the possible horizontal or vertical penetration of seawater intrusion. Therefore, the electrical geophysical prospecting based on ERT can be highly useful in areas lacking sufficient geological information and/or mechanical borehole data.  相似文献   

17.
Magnetotelluric (MT) investigations were carried out along a profile in the greenschist–granulite transition zone within the south Indian shield region (SISR). The profile runs over a length of 110 km from Kuppam in the north to Bommidi in the south. It covers the transition zone with 12 MT stations using a wide-band (1 kHz–1 ks) data acquisition system. The Mettur shear zone (MTSZ) forms the NE extension of Moyar–Bhavani shear zone that traverses along the transition zone. The regional geoelectric strike direction of N40°E identified from the present study is consistent with the strike direction of the MTSZ in the center of the profile. The 2-D conductivity model derived from the data display distinct high electrical resistivity character (10,000 Ω m) below the Archaean Dharwar craton and less resistive (< 3000 Ω m) under the southern granulite terrain located south of the MTSZ. The MTSZ separating the two regions is characterized by steep anomalous high conductive feature at lower crustal depths. The deep seismic sounding (DSS) study carried out along the profile shows dipping signatures on either side of the shear zone. The variation of deep electrical resistivity together with the dipping signature of reflectors indicate two distinct terrains, namely, the Archaean Dharwar Craton in the north and the Proterozoic granulite terrain towards south. They got accreted along the MTSZ, which could represent a possible collision boundary.  相似文献   

18.
Seawater intrusion is a major problem in urbanized coastal regions of India which is due to over exploitation of groundwater for various purposes. This study was carried out with the objective of assessing the zone of mixing between seawater and groundwater in the coastal aquifer in south of Chennai, Tamil Nadu, India using high resolution electrical resistivity tomography. High resolution electrical resistivity tomography was carried out in five profiles perpendicular to the sea using IRIS make SYSCAL Pro-96 system with 2.5 m or 5 m inter-electrode separation. The maximum length of the profile was 170 m which resulted in a depth of investigation of 28.7 m. The apparent resistivity measured in this area varies from 0.3 ohm-m to 30,000 ohm-m. The apparent resistivity of saturated zone decreases towards the sea, indicating the influence of seawater. This was also confirmed by measuring the electrical conductivity of groundwater, which gradually increases from 156 μS/cm to 3430 μS/cm towards the sea. Further, the concentration profiles of electrical conductivity, sodium, chloride and chloride / bicarbonate ratio are compared with the high resolution electrical resistivity tomography profile. The distance of influence of seawater is comparatively high in northern part than in southern part of the area. The high resolution electrical resistivity tomography was effectively used to determine the effect of seawater mixing with groundwater.  相似文献   

19.
Recently, the deterioration of water quality in the coastal zones of Lekki Peninsula area of Lagos due to saltwater infiltration into the freshwater aquifer has become a major concern. With the aim of providing valuable information on the hydrogeologic system of the aquifers, the subsurface lithology and delineating the groundwater salinity, vertical electrical resistivity (VES) sounding survey was carried out utilizing surface Schlumberger electrode arrays, and electrode spacing varying between 1 and 150 m. The DC resistivity surveys revealed significant variations in subsurface resistivity. Also, the VES resistivity curves showed a dominant trend of decreasing resistivity with depth (thus increasing salinity). In general, the presence of four distinct resistivity zones were delineated viz.: the unconsolidated dry sand (A) having resistivity values ranging between 125 and 1,028 Ωm represent the first layer; the fresh water-saturated soil (zone B) having resistivity values which correspond to 32–256 Ωm is the second layer; the third layer (zone C) is interpreted as the mixing (transition) zone of fresh with brackish groundwater. The resistivity of this layer ranges from 4 to 32 Ωm; while layer four (zone D) is characterized with resistivities values generally below 4 Ωm reflecting an aquifer possibly containing brine. The rock matrix, salinity and water saturation are the major factors controlling the resistivity of the formation. Moreover, this investigation shows that saline water intrusion into the aquifers can be accurately mapped using surface DC resistivity method.  相似文献   

20.
Integrated geoelectric, geological and geochemical investigations are carried out in Budge Budge and Dum Dum areas of south and north 24 Parganas district for ascertaining the prevailing hydrological condition and aquifer characteristic with chemical qualities of groundwater for drinking and irrigation purposes. The proposed areas are constituted of alluvium and marine sediments of Quaternary age being a part of Gangetic delta. Vertical electrical soundings (VES) of Budge Budge have delineated four to six layers consisting of top soils, the brackish water zone, clay layer, first fresh water zone, another clay layer and the bottom-most(sixth layer) second fresh water bearing zone. The first fresh water zone is located at a depth of 128 m with thickness of 43 m having resistivity range of 32 ohm.m to 37 ohm.m for VES locations BB2 and BB3. The resistivity of the deeper second fresh water bearing zone is varying from 47 ohm.m to 51 ohm.m. The interpreted VES results significantly correspond with the borehole litholog of Budge Budge area. Similar VES results are also obtained for Dum Dum area showing promising potential aquifer zone especially for VES locations DD3 and DD4. A litho-resistivity relation is also determined for the area. Total TDS content of Budge Budge ground water samples are ranging from 720 mg/l to 4400 mg/l and same is ranging from 1012 mg/l to 1930mg/l for Dum Dum ground water samples. According to IS standard, the value of major cations and anions are near to the permissible limit for Dum Dum but same is not observed in Budge Budge for drinking and irrigation purpose excepting location G7. According to Piper trilinear diagram, the ground water in Budge Budge area is sulphate rich type and in Dum Dum it is fresh in nature. Chemically, the groundwater samples from Dum Dum and Budge Budge is classified as (Ca+Mg+Cl+SO4) facies. The geochemical parameters like total hardness (TH), sodium adsorption ratio (SAR), soluble sodium percentage (SSP), Kelly’s ratio (KR), magnesium ratio (MR), residual sodium carbonate (RSC), corrosivity ratio (CR), Gibb’s ratio-I&II (GR-I & GR-II), chloro alkaline indices (CAI-I & CAI-II), permeability index (PI), sea water contamination (SWC) are also determined for better understanding of the quality of groundwater in the above areas.  相似文献   

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