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1.
Despite its extreme aridity, the Badain Jaran Desert is rich in groundwater. In the southeastern part of the desert, it is
characterized by coexistence of high megadunes and a great number of lakes. Deuterium and oxygen 18 isotope compositions as
well as hydrochemistry of groundwater, lake water, soil water and river water were investigated in detail to gain an insight
into their relationships and the origin of the ground-water. The results show that the groundwater and the lake water are
genetically related, but unrelated to local precipitation and the leakage of Heine River at northern slope of Qilian mountain.
δD and δ 18O values of deep soil water (lower than 40 cm) and groundwater plot on the same evaporation line E11, which shows that they
have the same recharge source. The point of intersection between E11 and LMWL suggests that the groundwater originates from
the water resource which has a weighted mean value that is lighter by some 6‰ δ 18O than the local precipitation in Badain Jaran Desert. 3H data of water samples shows that the groundwater in Badain Jaran Desert originates from the water recharged after the nuclear
test. The deep fault zone underground maybe the water circulation channel based on Helium analysis of groundwater. The result
has guiding significance to rational exploitation and utilization of the local groundwater. 相似文献
2.
Groundwater is a valuable resource in the semiarid Ordos Plateau region where abundant mineral resources, such as coal, natural
gas, and halite, are present. With resources development, groundwater demand will increase dramatically. The origin identification
and recharge estimates of groundwater are significant components of sustainable groundwater development in the Ordos Plateau.
Groundwater and precipitation samples were taken and the isotopic compositions δ 2H, δ 18O, and chloride were analyzed to identify groundwater origins and to estimate recharge rates. The δ 2H and δ 18O of the groundwater show that the groundwater recharge is of meteoric origin. The chloride mass balance (CMB) method was
used to quantify recharge rates of groundwater in the Ordos Plateau, which varies from 2.93 to 22.11% of the effective annual
rainfall. Recharge rates estimated by CMB were compared with values obtained from other methods and were found to be in good
agreement. This study can be used to develop effective programs for groundwater management and development. 相似文献
4.
Assessing the seasonal variation of groundwater recharge is important for effective management of groundwater resources. Stable
isotopes of oxygen and hydrogen were used to estimate the sources of groundwater and seasonal contributions of precipitation
to groundwater recharge in Chih-Pen Creek basin of eastern Taiwan. Based on the isotopes of precipitation ( n = 177), two different local meteoric water regression lines (LMWL) can be obtained for the different seasons: δD = 8.06 18O + 10.08 for wet season precipitation (May through October) and δD = 8.65δ 18O + 17.09 for dry season precipitation (November through April). The slope and intercept of regression line for wet season
precipitation are virtually identical to the global meteoric water line (GMWL) of Craig ( 1961). In contrast to during dry season precipitation due to evaporation effect the intercept of 17.09 is much higher than of
the GMWL of 10. The results show the stable isotopes compositions of precipitation decrease with increasing rainfall amount
and air temperature, due to the amount effect of precipitation is pronounced. The amount effect is clearly but do not show
the temperature effect from January to December 2007. Using a mass-balance equation, a comparison of deuterium excess or d values of precipitation and groundwater indicates the groundwater consist of 76% wet season precipitation and 24% dry season
precipitation, representing a distinct seasonal variation of groundwater recharge in study area. About 79% of the groundwater
is recharged from the river water of the mountain watershed and 21% is from the rain that falls on the basin. 相似文献
5.
Compositions of deuterium and 18O isotopes of 90 representative samples indicate that thermal groundwater in most parts of China is meteoric in origin. Latitude,
altitude, and continent effects have significant bearing on the values of δD and δ 18O of the hot water samples. Oxygen-18 shift is not significant in most of the thermal groundwater, especially the hot water
of low-to-moderate temperature. Slight oxygen-18 shift is only found in some hot springs of high temperature in Tibet and
western Yunnan and in thermal groundwater of low-to-moderate temperature in the deep-seated carbonate aquifers in the northern
North China Plain (including the Tianjin area). Near-surface boiling may causes the shift of the former and the latter may
be attributed to exchange of oxygen-18 between water and carbonates in the geothermal systems of taphrogenic basin-type. Hot
springs in Tibet and western Sichuan have very low contents of δD and δ 18O, possibly due to recharge of precipitation and snow-melting water of extremely depleted δD and δ 18O values at high latitudes of several thousands of meters. 相似文献
6.
On the basis of the hydrogeology of the Dousitu River drainage basin, the changes of water flow rate, δ 18O and δD along the Dousitu River are discussed according to measured and analytical results. Changes of flow rate along the
Dousitu River agree well with groundwater level contours and the recharge and discharge of groundwater to the river. When
compared with other types of water in the area, it is obvious that the 18O and D of river waters have experienced evaporation. The changes of δ 18O and δD along the Dousitu River are mainly caused by combined effects of groundwater recharge and river water evaporation.
The recharge of groundwater makes δ 18O and δD of the river water decrease. Evaporation makes δ 18O and δD of the river water increase. The evaporation fractions of the river water are calculated using the kinetic fractionation
theory. Results showed as much as 10–30% of water was evaporated in different segments of Dousitu River. 相似文献
7.
Unplanned exploitation of groundwater constitutes emerging water-related threats to MayoTsanaga River Basin. Shallow groundwater
from crystalline and detrital sediment aquifers, together with rain, dams, springs, and rivers were chemically and isotopically
investigated to appraise its evolution, recharge source and mechanisms, flow direction, and age which were used to evaluate
the groundwater susceptibility to contamination and the basin’s stage of salinization. The groundwater which is Ca–Na–HCO 3 type is a chemically evolved equivalent of surface waters and rain water with Ca–Mg–Cl–SO 4 chemistry. The monsoon rain recharged the groundwater preferentially at an average rate of 74 mm/year, while surface waters
recharge upon evaporation. Altitude effect of rain and springs show a similar variation of −0.4‰ for δ 18O/100 m, but the springs which were recharged at 452, 679, and 773 m asl show enrichment of δ 18O through evaporation by 0.8‰ corresponding to 3% of water loss during recharge. The groundwater which shows both local and
regional flow regimes gets older towards the basins` margin with coeval enrichment in F − and depletion in NO 3
−. Incidentally, younger groundwaters are susceptible to anthropogenic contamination and older groundwaters are sinks of lithologenic
fluoride. The basins salinization is still at an early stage. 相似文献
8.
The present work was conducted in the Sinai Peninsula (1) to identify the recharge and flow characteristics and to evaluate
the continuity of the Lower Cretaceous Nubian Sandstone aquifer; and (2) to provide information for the aquifer's rational
appraisal. Isotopic and hydrochemical compositions combined with the geological and hydrogeological settings were used for
this purpose.
A considerable depletion in isotopic content (oxygen-18 and deuterium) and low d-excess values exist in the studied groundwater,
reflecting the contribution of old meteoric water that recharged the aquifer in pluvial times. Modern recharge also occurs
from precipitation that falls on the aquifer outcrops. The wide scatter of the data points around the two meteoric lines,
the global meteoric water line (GMWL) and Mediterranean meteoric water line (MMWL), in the δ 18O–δD diagram indicates considerable variation in recharge conditions (amount, altitude, temperature, air masses, distances
from catchment, overland flow, etc.). The isotopic composition in the El-Bruk area is minimum ( 18O=–9.53‰), very close to the average value of the Western Desert Nubian Sandstone ( 18O=–10‰), where the local structural and lithologic conditions retard groundwater flow and the main bulk of water becomes noncyclic.
The continuity of the aquifer in northern and central Sinai is evidenced by the isotopic similarity between samples taken
from above and below the central Sinai Ragabet El-Naam fault, the distribution of potentiometric head, and hydrogeological
cross sections.
The combination of isotopic composition in terms of 18O and chemical composition in terms of TDS and salt contents is the basis for separating the studied groundwater into groups
that reflect the recharge sources and isotopic and chemical modifications during flow.
Electronic Publication 相似文献
9.
Groundwater is of utmost significance to socio-economic development and ecological recovery for the Loess Plateau. However,
studies regarding the mechanism governing groundwater recharge over this area appear to be inadequate. This study is to examine
the spatio-temporal variations of δ 2H and δ 18O in precipitation and shallow groundwater. On the basis of this, the mechanisms governing shallow groundwater recharge were
explored. Precipitation and groundwater were sampled monthly from May to October during the period 2004–2006 at 13 sites in
the Chabagou Catchment (187 km 2). In the Caopingxigou Experimental Watershed (0.1 km 2), meteorological variables were observed and rainfall larger than 5 mm was sampled immediately after each rain event. Across
the area, 90% of the precipitation occurred from May to September primarily in the form of heavy rains or rainstorms with
great spatial variability. There were about 30 localized rains in each year. It was indicated that there existed notable seasonality
and pronounced spatial variability in precipitation isotopic compositions. Contributing factors and indications of isotopic
compositions, as well as their climatic indications such as monsoon intensities and mixing processes of water vapor, were
investigated. The δ 2H–δ 18O relation of groundwater was found to be δ 2H = 3.22 × δ 18O − 38.1, deviating from the local meteoric water line δ 2H = 7.57 × δ 18O + 3.9. The range of δ values in groundwater is shrunken to be 15–21% of that in individual precipitations, and groundwater in the middle reaches
shows a wider range of δ values. Isotopic results showed that groundwater originates from precipitation with hydrogen and oxygen isotopic compositions
being −69 and −9.7‰, respectively, and most groundwater experiences serious evaporation and adequate mixing with old water
during infiltration or percolation in the aerated zone. It was also founded that obvious fluctuations of isotopic compositions
in groundwater mainly appear in the middle reaches especially at sites that are close to valleys, suggesting varying sources
of groundwater from precipitation, precipitation runoff, isotopically enriched surface water and/or lateral recharge of adjacent
groundwater. 相似文献
10.
降水模拟实验证明,鄂尔多斯北部沙土层单次降水入渗最大深度小于1 m,降水在土壤中受到蒸发后排泄到大气中。实验证实,只有当土壤含水率达到最大田间持水率,吸附在土颗粒表面的薄膜水才能克服电磁引力转化为重力水,在重力的作用下继续下渗。鄂尔多斯北部的年降水量小而蒸发量大,降水入渗土壤不能形成累积效应,无法形成连续下渗的重力水流。同位素示踪分析表明,土壤水主要来源于地下潜水,结合土壤含水率与TDS分析证实,地下水是通过薄膜水与蒸发-凝结方式补给到土壤水中,薄膜水从高温区向低温区流动,对于等温的薄膜水而言,薄膜水从厚层向薄层流动。同位素分析表明,都思兔河流域的河水、泉水、井水、湖泊、土壤水接受相同的外源水补给。鄂尔多斯盆地降水比地表水与地下水明显富集重同位素,不符合补给区降水同位素特征。鄂尔多斯盆地地下水分水岭与基底断裂带重合,据此推断,外源水以深循环方式通过基底断裂带补给鄂尔多斯盆地,在干旱地区形成自流井群。 相似文献
11.
Chemical and isotopic analyses of groundwater from the carbonated Jurassic aquifers in the Gijón-Villaviciosa basin (Asturias,
northern Spain) were carried out. Nine springs were sampled to determine major cations and anions, as well as the stable isotopes
of the water molecule (δ 2H and δ 18O) and sulphate (δ 34S) values. Also, δ 34S values from gypsum coming both from Triassic rocks and bottom of Jurassic sequence were also determined. The results obtained
were used to classify the waters with a genetic criteria in three groups: (1) waters with a high gypsum influence, with sulphate
coming from Jurassic gypsum, (2) waters without gypsum influence, where sulphate source could be atmospheric deposition from
industrial processes and marine aerosol, and (3) waters with some gypsum influence, in which sulphate origin could be a combination
of different sources. In relation to recharge, δ 2H and δ 18O values were close to those of Global Meteoric Water Line and fit a local line that suggests a meteoric origin. The estimated
elevations for spring recharge are in agreement with those obtained from hydrogeological maps. 相似文献
12.
Chemical compositions and stable isotope ratios of water and sulphate were used to characterise sources and processes responsible
for elevated concentrations of sulphate and other constituents in groundwater from aquifers at Colima State along Mexico’s
Pacific Coast. The δ 18O and δ 2H values of the groundwater were similar to those of precipitation indicating a meteoric origin, and recharge processes are
relatively uniform in large parts of the study area with only slight local evaporation effects. δ 34S sulphate and δ 18O sulphate analyses indicated that high sulphate concentrations of up to 1,480 mg/l are mainly due to dissolution of evaporites and
volcanic exhalations. Chloride is largely related to sources other than seawater. The Marabasco sub basin is affected by anthropogenic
contamination through manganese and iron ore mining activities. The obtained knowledge regarding sources and areas of contamination
will be essential for the development and design of a water quality monitoring program in the study area. 相似文献
13.
The groundwater in headwater region is an important recharge source for the adjacent mountain-front plain. In order to reveal
the relationship among precipitation, soil water and groundwater, from June to September in 2004, stable isotopes (deuterium
and oxygen-18) in precipitation and soil waters at the depths of 10, 20, 30, 50, 70, 90, and 110 cm were analyzed at two sites
covered by black locust ( Robinia Pseudoacia L.) (Site A) and grass predominated by Themeda triandra (T. japonica (Willd.) Tanaka) and Bothriochloa ischaemum (B. ischaemum (L.) Keng) (Site B) in an experimental catchment at Taihang Mt., North China, respectively. The δ 18O of precipitation in daily rain events shows large variations (−13.3 to −4.3‰) with a mean of 8.1‰. The δ 18O and δ D of soil waters along profiles in two sites suggest that the influence of canopy cover was just up to 10 cm in top
soil water. The soil water moved over the zero flux plane at 70 cm in-depth is expected to escape the evaporative effect at
the end of September in both sites. The results show that the stable isotope, instead of tritium as tradition, can be used
to trace the soil water behaviors based on the movement of isotopic peak along the vertical profiles in this semi-arid and
semi-humid mountainous region. The infiltration depths of soil water in Taihang Mt. are 12 and 10 mm/day from June to September
in 2004 in Site A and Site B, respectively. Tracing by stable isotope, recharge fluxes of soil water to local groundwater
are of 3.8 and 3.2 mm/day in Site A and Site B, respectively. The results provide desirable information for assessment of
local groundwater resources.
An erratum to this article can be found at 相似文献
14.
Large salinated areas are distributed in the middle and east of the North China Plain (NCP), where the fresh water shortage is serious. In this study, two sites in Cangzhou (CZ) and Hengshui (HS) of Hebei Province were selected to study the dynamics of shallow groundwater level and salinity. Electrical conductivity (EC) of groundwater was combined with the isotope compositions of δ 18O and δ 2H to identify the origin of salinity. Results showed that the dynamics of groundwater level at both sites were mainly controlled by precipitation and evaporation. Soil texture and structure played a significant role in the dynamics of salinity. The summer precipitation diluted the EC of groundwater at the HS site with homogeneous soil of sand loam, suggesting the larger infiltration rate; however, it did not dilute the EC at the CZ site with heterogeneous soil of sand loam and silt loam, suggesting that the summer precipitation could not recharge the groundwater directly. In winter, the EC decreased rapidly due to the temperature gradient underground if the groundwater was above the threshold level (at least 3 m below the ground surface) after the rainy season. Isotopes of δ 18O and δ 2H showed that precipitation was the major recharge source for the groundwater at the two sites. The salt mainly comes from the dissolution of soil or rock at the CZ site. While, the evaporation effect was strong at the HS site leading to the increase of the salt concentration. 相似文献
15.
The Dongsheng sandstone-type uranium deposit is one of the large-sized sandstone-type uranium deposits discovered in the northern part of the Ordos Basin of China in recent years. Geochemical characteristics of the Dongsheng uranium deposit are significantly different from those of the typical interlayered oxidized sandstone-type uranium ore deposits in the region of Middle Asia. Fluid inclusion studies of the uranium deposit showed that the uranium ore-forming temperatures are within the range of 150–160℃. Their 3He/4He ratios are within the range of 0.02–1.00 R/Ra, about 5–40 times those of the crust. Their 40Ar/36Ar ratios vary from 584 to 1243, much higher than the values of atmospheric argon. The δ18OH2O and δD values of fluid inclusions from the uranium deposit are -3.0‰– -8.75‰ and -55.8‰– -71.3‰, respectively, reflecting the characteristics of mixed fluid of meteoric water and magmatic water. The δ18OH2O and δD values of kaolinite layer at the bottom of the uranium ore deposit are 6.1‰ and -77‰, respectively, showing the characteristics of magmatic water. The δ13CV-PDB and δ18OH2O values of calcite veins in uranium ores are -8.0‰ and 5.76‰, respectively, showing the characteristics of mantle source. Geochemical characteristics of fluid inclusions indicated that the ore-formation fluid for the Dongsheng uranium deposit was a mixed fluid of meteoric water and deep-source fluid from the crust. It was proposed that the Jurassic-Cretaceous U-rich metamorphic rocks and granites widespread in the northern uplift area of the Ordos Basin had been weathered and denudated and the ore-forming elements, mainly uranium, were transported by meteoric waters to the Dongsheng region, where uranium ores were formed. Tectonothermal events and magmatic activities in the Ordos Basin during the Mesozoic made fluids in the deep interior and oil/gas at shallow levels upwarp along the fault zone and activated fractures, filling into U-bearing clastic sandstones, thus providing necessary energy for the formation of uranium ores. 相似文献
16.
Figeh watershed spring is one of the important groundwater aquifer, which is considered a major source for drinking waters
of Damascus city and countryside. The origin identification and recharge estimates of groundwater are significant components
of sustainable groundwater development in this Mountain karst aquifer of Figeh spring. During the period 2001–2009, monthly
groundwater and precipitation samples were taken and the isotopic compositions of δ 18O, δ 2H, and chloride contents were analyzed to identify groundwater origins and to estimate recharge rates. The δ 18O, δ 2H of the groundwater show that the groundwater recharge is of meteoric origin. The chloride mass balance (CMB) method was
used to quantify recharge rates of groundwater in the Mountain karst aquifer of Figeh spring. The recharge rate varies from
192 to 826 mm/year, which corresponds to 43 and 67% of the total annual rainfall. Recharge rates estimated by CMB were compared
with values obtained from other methods and were found to be in good agreement. This study can be used to develop effective
programs for groundwater management and development. 相似文献
17.
The 18O and 2H (HDO) compositions are summarized for sampled springs ( n = 81) within the Elwha watershed (≈692 km 2) on the northern Olympic Peninsula. Samples, collected during 2001–2009, of springs ( n = 158), precipitation ( n = 520), streams ( n = 176), and firn ( n = 3) assisted the determinations for meteoric composition of recharge waters. The local mean water line (LMWL) is defined
as δ 2H = 8.2δ 18O − 9.3 for the watershed. Recharge history is surmised from groundwater ages ranging from 5 ± 3 years (apparent 85Kr) to 9,490 ± 420 14C cal years BP. About 56% of the springs were recharged over the last 1,000 years while 13% of springs were recharged over
5,000 years ago. Spring HDO values fluctuate between −11.8 to −15.6‰ δ 18O and −90.9 to −119.4‰ δ 2H. Deuterium excess values predominate around 4–6‰. The HDO proxy records from springs suggest a pronounced paleoclimate shift
in air masses near 5,000 year BP on the Peninsula. 相似文献
18.
Geochemistry and environmental tracers were used to understand groundwater resources, recharge processes, and potential sources of contamination in the Rio Actopan Basin, Veracruz State, Mexico. Total dissolved solids are lower in wells and springs located in the basin uplands compared with those closer to the coast, likely associated with rock/water interaction. Geochemical results also indicate some saltwater intrusion near the coast and increased nitrate near urban centers. Stable isotopes show that precipitation is the source of recharge to the groundwater system. Interestingly, some high-elevation springs are more isotopically enriched than average annual precipitation at higher elevations, indicating preferential recharge during the drier but cooler winter months when evapotranspiration is reduced. In contrast, groundwater below 1,200 m elevation is more isotopically depleted than average precipitation, indicating recharge occurring at much higher elevation than the sampling site. Relatively cool recharge temperatures, derived from noble gas measurements at four sites (11–20 °C), also suggest higher elevation recharge. Environmental tracers indicate that groundwater residence time in the basin ranges from 12,000 years to modern. While this large range shows varying groundwater flowpaths and travel times, ages using different tracer methods ( 14C, 3H/ 3He, CFCs) were generally consistent. Comparing multiple tracers such as CFC-12 with CFC-113 indicates piston-flow to some discharge points, yet binary mixing of young and older groundwater at other points. In summary, groundwater within the Rio Actopan Basin watershed is relatively young (Holocene) and the majority of recharge occurs in the basin uplands and moves towards the coast. 相似文献
19.
A Triassic carbonate unit has been intensively drained by zinc and lead ore mines and numerous borehole fields since the nineteenth
century. Its groundwater recharge has increased due to: pumping of water from boreholes, mining activity, and urbanization.
An approach to determine the amounts of the recharge at a variety of spatial scales is presented in the paper. Different methods
were used to identify and quantify recharge components on a regional and local scale: mathematical modelling was performed
for four aquifers included in an aquifer system, an analytical estimation based on the assumption that an average recharge
is equal to the average discharge of the hydrogeological system—for six man-made drainage centres, and the method of water
level fluctuation (WLF) was applied in one observation borehole. Results of modelling have been supplemented by observation
of environmental tracers (δ 18O, δ 2H, 3H), noble gases temperatures, and 4He exc in groundwater. The regional aquifer’s current recharge according to estimations performed by means of modelling varies from
39 to 101 mm/year on average. Depending on the aquifer site the average precipitation ranges from 779 to 864 mm/year. In the
confined part of the aquifer average recharge ranges from 26 to 61 mm/year. Within outcrops average recharge varies from 96
to 370 mm/year. Current recharge estimated by the analytical method for man-made drainage centres varies from 158 up to 440 mm/year.
High values are caused by different recharge sources like precipitation, induced leakage from shallow aquifers, and water
losses from streams, water mains and sewer systems. Pumping of water, mining and municipal activities constitute additional
factors accounting for the intensified recharge. 相似文献
20.
Natural springs have the potential to provide important information on hydrogeochemical processes within aquifers. This study used traditional and classic technical methods and procedures to determine the characteristics and evolution of springs to gain further knowledge on the differences between hot saline springs and cold fresh springs. In a short river segment near Wenquanzhen in the eastern Sichuan Basin, southwest China, several natural springs coexist with total dissolved solids (TDS) ranging from less than 1 to 15 g/L and temperatures from 15 to 40 °C. The springs emanate from the outcropping Lower and Middle Triassic carbonates in the river valley cutting the core of an anticline. The cold springs are of Cl·HCO3-Na·Ca and Cl·SO4-Na types, and the hot saline springs are mainly of Cl-Na type. The chemistry of the springs has undergone some changes with time. The stable hydrogen and oxygen isotopes indicate that the spring waters are of a meteoric origin. The salinity of the springs originates from dissolution of minerals, including halite, gypsum, calcite and dolomite. The evolution of the springs involves the following mechanisms: the groundwater receives recharge from infiltration of precipitation, then undergoes deep circulation in the core of the anticline (incongruent dissolution of the salt-bearing strata occurs), and emerges in the river valley in the form of hot springs with high TDS. Groundwater also undergoes shallow circulation in the northern and southern flanks of the anticline and appears in the river valley in the form of cold springs with low TDS. 相似文献
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