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Saline groundwaters were recovered from undisturbed (Restigouche deposit) and active (Brunswick #12 mine) Zn–Pb volcanogenic massive sulfide deposits in the Bathurst Mining Camp (BMC), northern New Brunswick, Canada. These groundwaters, along with fresh to brackish meteoric ground and surface waters from the BMC, have been analyzed to determine their major, trace element and stable isotopic (O, H, C, and B) compositions. Saline groundwaters (total dissolved solids = 22–45 g/L) are characterized by relatively high Na/Ca ratios compared to brines from the Canadian Shield and low Na/Clmolar and d 11 B isotopic compositions (� 2.5& to 11.1&) compared to seawater. Although saline waters from the Canadian Shield commonly have oxygen and hydrogen isotopic compositions that plot to the left of the global meteoric water line, those from the BMC fall close to the water line. Fracture and vein carbonate minerals at the Restigouche deposit have restricted carbon isotopic compositions of around � 5& to � 6&. The carbon isotopic compositions of the saline waters at the Restigouche deposit (+12& d 13 CDIC) are the result of fractionation of dissolved inorganic carbon by methanogenesis. We suggest that, unlike previous models for shield brines, the composition of saline waters in the BMC is best explained by prolonged water–rock reaction, with no requirement of precursor seawater. We suggest that elevated Br/Cl ratios of saline waters compared to seawater may be explained by differential uptake of Br and Cl during groundwater evolution through water–rock reaction. � 2007 Elsevier Ltd. All rights reserved.

Summary Stable isotope (δD and δ18O) signatures of three principal groundwater recharge areas in the 21,000-km2 upper Klamath Basin are used to infer recharge sources for aquifers in the interior parts of the basin. Two of the principal recharge areas, the Cascade Range on the western and southern margin of the basin and uplands along the eastern margin, are defined by mean annual precipitation that exceeds approximately 60 cm. A third recharge area coincides with the extensive irrigation canal system in the south central part of the basin. The stable isotope signature for Cascade Range groundwater falls near the global meteoric water line (GMWL). The stable isotope signature for the groundwater of the eastern basin uplands also falls near the GMWL, but is depleted in heavy isotopes relative to the Cascade Range groundwater. The stable isotope signature for water from the irrigation canal system deviates from the GMWL in a manner indicative of fractionation by evaporation. Groundwater provenance was previously unknown for two aquifers of interest: that supplying deep (225–792 m), large-capacity irrigation wells along the Oregon–California border, and that of the geothermal system near Klamath Falls. Groundwater produced by the deep irrigation wells along the Oregon–California border appears to be a mixture of eastern-basin groundwater and water with an evaporative isotopic signature. The component with an evaporative isotopic signature appears in some places to consist of infiltrated irrigation water. Chloride data suggest that much of the component with the evaporative isotopic signature may be coming from an adjacent subbasin. After accounting for the 18O shift common in geothermal waters, isotope data suggest that the geothermal groundwater in the upper Klamath Basin may emanate from the eastern basin uplands. Findings demonstrate that stable isotope and chloride data can illuminate certain details of a regional groundwater flow system in a complex geologic setting where other hydrologic data are ambiguous.

The long-lived halogen radioisotopes 129I and 36Cl provide valuable information regarding the source of fluids in hydrocarbon systems and in localized areas where infiltration of younger meteoric water has occurred. Despite the utility of these two isotopes in providing time-signatures for fluid end-members, considerable uncertainty remains regarding the interpretation of “intermediate-age” waters in hydrologic systems. These waters are likely the result of the combination of two or more halogen sources at some time in the past, each with its own characteristic concentration and isotopic composition. In order to unravel the evolution of these “intermediate-age” waters, the effect that infiltration of meteoric water has on the isotopic composition of older formation waters is modeled. Also evaluated is the effect that the timing of dilution has on 129I and 36Cl signatures observed in the present, specifically, the hypothesis that halogen isotopic signatures imparted by the mixing of brine and meteoric waters early in the development of a sedimentary basin are quantitatively different from those imparted by the mixing of old brines with recent meteoric waters. The modeled results are compared to previously published isotopic data from production wells in the Fruitland Formation coalbed methane system. Portions of the basin preserve enough of the original brine source to retain 129I/I ratios roughly recording the age of deposition of organic matter (73–76 Ma) even where some degree of dilution by meteoric water has occurred. However, the 129I signatures of waters that presently contain less than 10% of the original formation water component indicate that mixing has occurred within the past 10 Ma, consistent with recently published 4He data. Both 36Cl concentrations and 36Cl/Cl ratios show that waters containing more than 10% formation water are all in secular equilibrium with the host formation coals. In contrast, waters with less than 1% of the original formation water’s Cl− content all have 36Cl/Cl ratios which are greater than secular equilibrium values, indicating the migration of meteoric water into the coal formation more recently than 2 Ma. Although 36Cl signatures in the Fruitland Formation are not significantly affected by anthropogenic input, 129I/I ratios in a subset of samples that retain less than 1% of the initial formation water component suggest input of anthropogenic 129I during the past 50 a.

Summary Stable isotopes, radiogenic isotopes, and major ion chemistry are used to constrain flow paths in a fracture-controlled regional groundwater flow system in far west Texas. The flow system occurs in Permian and Cretaceous sedimentary rocks and Cenozoic alluvial basin fill. Samples from springs and wells in the study area were analyzed for major ions and hydrogen, oxygen, and strontium isotopes. δD and δ18O values fall close to the global meteoric water line, indicating that these values have not been significantly affected by evaporation or mineral–water reactions. δ18O values from samples along the regional flow path are lower by as much as 3‰ relative to local recharge values; the distribution of stable isotope values throughout the study area suggests that lower δ18O values represent recharge during cooler climatic conditions rather than latitude or altitude effects. 87Sr/86Sr values for water samples from along the regional flow path range from 0.7093 to 0.7148, with the highest values at the upgradient end of the flow system. These values are significantly higher than expected for groundwaters dominated by dissolution of Permian and Cretaceous marine carbonates and evaporites. The high 87Sr/86Sr values reflect dissolution of minerals of Precambrian and early Paleozoic origin in the crystalline rocks of the Carrizo and Baylor mountains and alluvial basin fill at the upgradient end of the flow system. Contours of 87Sr/86Sr values indicate a zone of high 87Sr/86Sr water that corresponds to the regional groundwater flow paths. Mass-balance mixing models and mineral reactions models indicate a three end-member mixing system modified by dissolution of strontium-bearing minerals in the alluvial fill at the upgradient end of the flow system.

Continuous-flow isotope ratio mass spectrometry (CF-IRMS) was used to compare (2)H isotopic composition at natural abundance level of human scalp hair and fingernail samples collected from subjects worldwide with interpolated delta(2)H precipitation values at corresponding locations. The results showed a strong correlation between delta(2)H values of meteoric water and hair (r(2) = 0.86), while the corresponding correlation for nails was not as strong (r(2) = 0.6). Offsets of -180 per thousand and -127 per thousand were observed when calculating solutions of the linear regression analyses for delta(2)H vs. delta(18)O correlation plots of hair and nail samples, respectively. Compared with the +10 per thousand offset of the global meteoric water line equation these findings suggested that delta(18)O data from hair and nail would be of limited diagnostic value. The results of this pilot study provide for the first time tentative correlations of (2)H isotopic composition of human hair and nails with local water. Linear regression analyses for measured delta(2)H values of human hair and nails vs. water yielded delta(2)H(hair) = 0.49 x delta(2)H(water) - 35 and delta(2)H(nails) = 0.38 x delta(2)H(water) - 49, respectively. The results suggest that (2)H isotopic analysis of hair and nail samples can be used to provide information regarding an individual's recent geographical life history and, hence, location. The benefit of this technique is to aid identification of victims of violent crime and mass disasters in circumstances where traditional methods such as DNA and fingerprinting cannot be brought to bear (or at least not immediately).

Jordan is classified as an arid to semi-arid country with a population according to 1999 estimates of 4Ð8 millions inhabitants and a growth rate of 3Ð4%. Efficient use of Jordan’s scarce water is becoming increasingly important as the urban population grows. This study was carried out within the framework of the joint European Research project ‘Groundwater recharge in the eastern Mediterranean’ and describes a combined methodology for groundwater recharge estimation in Jordan, the chloride method, as well as isotopic and hydrochemical approaches. Recharge estimations using the chloride method range from 14 mm year � 1 (mean annual precipitation of 500 mm) for a shallow and stony soil to values of 3Ð7 mm year � 1 for a thick desert soil (mean annual precipitation of 100 mm) and values of well below 1 mm year � 1 for thick alluvial deposits (mean annual rainfall of 250 mm). Isotopically, most of the groundwater in the Hammad basin, east Jordan, falls below the global meteoric water line and far away from the Mediterranean meteoric water line, suggesting that the waters are ancient and were recharged in a climate different than Mediterranean. Tritium levels in the groundwater of the Hammad basin are less than the detection limit (

This paper reviews observation- and model-based studies of stable isotopes in precipitation and discusses the Global Network for Isotopes in Precipitation (GNIP) and other regional networks and projects involving isotope observations. Using data from the latest GNIP/Isotope Hydrology Information System (ISOHIS) database, the annual and monthly variabilities of δD-δ18O relationships, the temperature effect, and the amount effect for δ18O were calculated as averages for the Northern Hemisphere, Southern Hemisphere, and globe. At the global scale, the global Meteoric Water Line (MWL) was δD = 8.00 × δ18O + 9.62 (R2 = 0.99), the temperature effect was 0.53‰/°C (R2 = 0.71), and the precipitation amount effect was -1.05‰/100 mm (R2 = 0.20). Comparisons of modeled and observed temperature and amount effects indicate that most General Circulation Models (GCMs) have reproduced the present climate well. This paper also summarizes the use of stable isotopes in precipitation as proxy data for climate variability and water origins, as well as the results of recent isotope-observation studies, especially in the Asian monsoon regions.

Only a few studies have examined the variation of oxygen and hydrogen isotopes of seawater in NE Atlantic water masses, and data are especially sparse for intermediate and deep-water masses. The current study greatly expands this record with 527 δ18O values from 47 stations located throughout the mid- to low-latitude NE Atlantic. In addition, δD was analyzed in the 192 samples collected along the GEOTRACES North Atlantic Transect GA03 (GA03_e = KN199-4) and the 115 Iberia-Forams cruise samples from the western and southern Iberian margin. An intercomparison study between the two stable isotope measurement techniques (cavity ring-down laser spectroscopy and magnetic-sector isotope ratio mass spectrometry) used to analyze GA03_e samples reveals relatively good agreement for both hydrogen and oxygen isotope ratios. The surface (0-100 m) and central (100-500 m) water isotope data show the typical, evaporation related trend of increasing values equatorward with the exception for the zonal transect off Cape Blanc, NW Africa. Off Cape Blanc, surface water isotope signatures are modified by the upwelling of fresher Antarctic Intermediate Water (AAIW) that generally has isotopic values of 0.0 to 0.5‰ for δ18O and 0 to 2‰ for δD. Along the Iberian margin the Mediterranean Outflow Water (MOW) is clearly distinguished by its high δ18O (0.5-1.1‰) and δD (3-6‰) values that can be traced into the open Atlantic. Isotopic values in the NE Atlantic Deep Water (NEADW) are relatively low (δ18O: –0.1 to 0.5‰; δD: –1 to 4‰) and show a broader range than observed previously in the northern and southern convection areas. The NEADW is best observed at GA03_e Stations 5 and 7 in the central NE Atlantic basin. Antarctic Bottom Water isotope values are relatively high indicating modification of the original Antarctic source water along the flow path. The reconstructed δ18O-salinity relationship for the complete data set has a slope of 0.51, i.e. slightly steeper than the 0.46 described previously by Pierre et al. (1994) for the tropical to subtropical Northeast Atlantic. This slope decreases to 0.46 for the subtropical North Atlantic Central Water (NACW) and the MOW and to 0.32 for the surface waters of the upper 50 m. The δD-salinity mixing lines have estimated slopes of 3.01 for the complete data, 1.26 for the MOW, 3.47 for the NACW, and 2.63 for the surface waters. The slopes of the δ18O-δD relationship are significantly lower than the one for the Global Meteoric Water Line with 5.6 for the complete data set, 2.30 for the MOW, 4.79 for the NACW, and 3.99 for the surface waters. The lower slopes in all the relationships clearly reflect the impact of the evaporation surplus in the subtropics. EC Grant agreement n° 228344 - EUROFLEETS, C2007-FCT/319/2006 info:eu-repo/semantics/publishedVersion

Stable isotopes have been used to identify the characteristics of precipitation, evaporation, basin hydrology, and residence times. However, lakes in the cold regions are usually covered by ice for 5–6 months. To get a better understanding of stable isotopes characteristics and indications in lake ice bodies, ice and water were sampled during the icebound season in both the ice and water bodies in Dali Lake, and deuterium, oxygen-18 total nitrogen (TN), and the major ions were analyzed. The results showed that deuterium and oxygen-18 compositions (δD-δ18O) compositions in the ice body were greater than in the water body beneath, scattered on a straight line, and deviating downward from the global meteoric water line in the top right. The ice profile showed that the δD-δ18O compositions increased from the ice surface downward and decreased near to the bottom. In contrast, the TN and the major ions in the ice decreased from the ice surface downward and increased near to the bottom, meaning that the concentrations of δ18O had a negative correlation with the concentrations of TN and major ions. These indicated that stable isotopes can be used for tracing the nutriment and ion transport processes in the ice body.

Hydrochemical and stable isotope (18O and 2H) analyses of groundwater samples were used to establish the hydrochemistry of groundwater in the Ankobra Basin. The groundwater was generally mildly acidic, low in conductivity and undersaturated with respect to carbonate phases. Major ions except bicarbonate were low and dissolved silica was moderately high. Silicate minerals weathering is probably the main process through which major ions enter the groundwater. Groundwater samples clustered tightly along the Global Meteoric Water Line suggesting integrative, smooth and rapid recharge from meteoric origin. The majority of the boreholes and a few hand dug wells cluster towards the Ca–Mg–HCO3 dominant section of the phase diagram, in conformity with the active recharge and short residence time shown by the isotope data. Aluminium, arsenic, manganese, iron and mercury were the only trace metals analysed with concentrations significantly above their respective detection limits. Approximately 20%, 5%, 40% and 25% respectively of boreholes had aluminium, arsenic, iron and manganese concentrations exceeding the respective WHO maximum acceptable limits for drinking water. The relatively large percentage of boreholes with high concentration of aluminium reflects the acidic nature of the groundwater.

Stable isotopic composition of hydrogen and oxygen (d2H and d18O) and tritium activity (3H) were monitored in monthly precipitation at two continental stations (Ljubljana, Zagreb) and six stations along the eastern Adriatic coasts of Slovenia and Croatia in the period 2001 – 2003. Mean air temperatures and amount of precipitation were also recorded. Distinct differences in both meteorological and isotopic data between the continental and maritime stations were observed. Seasonal variations in δ 18O are smaller at the maritime stations than at the continental ones due to smaller seasonal temperature variations. Good correlation between the δ 18O and δ 2H was obtained for each station, and the Local Meteoric Water Lines are close to the Global Meteoric Water Line with the decreasing trend of slope for the south-Adriatic stations (

The authors report a preliminary study of the light stable isotopic ( δ D, δ 13 C and δ 18 O) values for bulk archaeological birch bark tars, over a geographical (e.g. Greece to Norway) and chronological (9500–3000 BP) range. For δ 13 C an increase in fractionation with increase in latitude is observed in samples from Greece which are less depleted than those from northern Europe. There is no clear difference between the samples from northern Europe. There is no apparent trend in δ 13 C value with the 14 C age of the sample. Due to biosynthetic fractionation all the samples are significantly depleted in 2 H and enriched in 18 O relative to the global meteoric water line. This study indicates that archaeological birch bark tar from Greece can be distinguished from those of northern Europe; this separation is probably based on the extreme geographical range of the samples examined here. But this does provide evidence that the birch bark tars were probably made locally rather than traded.

This study was based on the analysis of isotopic compositions of hydrogen and oxygen in samples from precipitation, groundwater and stream water. In addition, parts of groundwater samples were dated by carbon-14 and tritium. These data are integrated to provide other views of the hydrologic cycle in the Hsinchu-Miaoli groundwater district. The groundwater district is principally composed of Pleistocene and Holocene aquifers. The Pleistocene aquifers are highly deformed by folding and faults into small sub-districts with areas of only tens of square kilometers. These aquifers are exclusively recharged by local precipitation. The Holocene aquifers cover narrow creek valleys, only tens of meters in thickness. The local meteoric water line (LMWL), constructed from rainfall samples in the Hsinchu Science Park, is described by the equation δD=8.02δ18O+10.16, which agrees with the global meteoric water line. In addition, the precipitation isotopic compositions can be categorized into two distinct end members: typhoon type and monsoon type. The groundwater isotopic compositions are perfectly located on an LMWL and can be considered a mixture of precipitations. Based on the mass balance of isotopic compositions of oxygen and hydrogen, infiltration is more active in the rainy season with depleted isotopic compositions. The amount of infiltration during May–September is roughly estimated to comprise at least 55% of the whole year’s recharge. The isotopic compositions of stream water are expressed by a regression equation: δD=7.61δ18O+9.62, which is similar to the LMWL. Although precipitation isotopic compositions are depleted during summer time, the isotopic compositions contrarily show an enriched trend in the upstream area. This is explained by the opposite altitude effect on isotopic compositions for typhoon-related precipitations.

Meteoric water that interacted with minerals during retrogressive metamorphism and hydrothermalism in the late-stage of mountain building processes contains hydrogen and oxygen isotopes that are potential proxies for palaeoelevation reconstruction in Antarctica. The effects of temperature on meteoric isotopic signatures, meteoric crustal infiltration processes, and the mechanisms of capture and preservation of meteoric δD and δ18O values in rock-forming minerals are discussed. Special emphasis is given to Antarctica’s geographical high-latitude position and climatic fluctuations over time and to the highmountain ranges of continental Antarctica, which were tectonically active regions in the past. In this context, a new compilation of recent Antarctic snow and ice δD and δ18O data is presented, by which we demonstrate that net elevations versus isotopic depletions are positively correlated for continental Antarctica - a prime requisite when estimating palaeoelevations.

Bottled and packaged waters are an increasingly significant component of the human diet. These products are regulated at the regional, national, and international levels, and determining the authenticity of marketing and labeling claims represents a challenge to regulatory agencies. Here, we present a dataset of stable isotope ratios for bottled waters sampled worldwide, and consider potential applications of such data for regulatory, forensic and geochemical standardization applications. The hydrogen and oxygen isotope ratios of 234 samples of bottled water range from -147 per thousand to +15 per thousand and from -19.1 per thousand to +3.0 per thousand, respectively. These values fall within and span most of the normal range for meteoric waters, indicating that these commercially available products represent a source of waters for use as laboratory working standards in applications requiring standardization over a large range of isotope ratios. The measured values of bottled water samples cluster along the global meteoric water line, suggesting that bottled water isotope ratios preserve information about the water sources from which they were derived. Using the dataset, we demonstrate how bottled water isotope ratios provide evidence for substantial evaporative enrichment of water sources prior to bottling and for the marketing of waters derived from mountain and lowland sources under the same name. Comparison of bottled water isotope ratios with natural environmental water isotope ratios demonstrates that on average the isotopic composition of bottled water tends to be similar to the composition of naturally available local water sources, suggesting that in many cases bottled water need not be considered as an isotopically distinct component of the human diet. Our findings suggest that stable isotope ratios of bottled water have the power to distinguish ultimate (e.g., recharge) and proximal (e.g., reservoir) sources of bottled water and constitute a potential tool for use in the regulatory monitoring of water products.

Hydrogen isotope ratios were measured on n-alkanes (n-C12 to n-C31) extracted from recent lake surface sediments along a N-S European transect to test if modern climate variability is recorded in these biomarkers. δD values of the n-alkanes are compared to δD values of meteoric water from the IAEA-GNIP database spanning a range from −119‰ in northern Sweden to −41‰ in southern Italy, to lake water δD values, and to mean annual temperatures, varying between −2.0°C in the north and 13.7°C in the south. δD values of the short-chained n-alkanes n-C12 to n-C20, excluding algal derived n-C17 and n-C19, are higher in the north and lower in the south. The isotopic fractionation e for hydrogen between meteoric water and the short-chained n-alkanes is increasing from N to S by more than 100‰ and is significantly correlated to mean annual temperature for n-C16 and n-C18. This suggests that these n-alkanes may originate from a different source in the northern lakes, possibly due to petroleum contamination, or are synthesized using a different biochemical pathway. The n-C17 and n-C19 alkanes of algal origin, the n-C21 and n-C23 alkanes originating from water plants, and the long-chain n-alkanes n-C25, n-C27, n-C29, and n-C31 of terrestrial origin, clearly correlate with δD values of meteoric water, lake water, and mean annual temperature, indicating that they excellently record the δD value of meteoric water. The mean hydrogen isotope fractionation eC17/w of −157‰ (SD = 13) between n-C17 and meteoric water is fairly constant over the wide range of different climates and lake environments, suggesting only minor influence of environmental factors on this biochemical fractionation. This suggests that δD values of n-C17 are suitable to reconstruct the isotopic composition of source water. The mean fractionation between the long-chain n-alkanes and water is −128‰ (SD = 12). The mean difference of 31‰ between both e values is likely due to evaporative enrichment of deuterium in the leaf water. If this is the only influence on the enrichment, the difference between the δD values of terrestrial and aquatic compounds might be suitable to reconstruct terrestrial evapotranspiration of the lake environment.

The Puyehue-Cordon Caulle area (40.5◦S) hosts one of the largest active geothermal systems of Southern Chile, comprising two main thermal foci, Cordon Caulle and Puyehue. Cordon Caulle is a NW-trending volcanic depression dominated by fumaroles at the top (∼1500 m) and boiling springs at the northwest end (∼1000 m). In the latter, the alkaline-bicarbonate composition of the springs with low Mg (

The contribution of Chinese sources to the acid deposition in neighbouring countries in Far East Asia has been disputed. This study is to examine the isotopic composition of the S in the natural waters in the Chuncheon area to see if the isotopic composition can be an indicator of the pollution sources in the area. Meteoric water sampled between September 2000 and July 2001 and surface water sampled in December 2000 and April 2001 in the area were collected to examine their chemical and isotopic compositions. The pH values of the meteoric water lie between 4.02 and 6.89, but mostly lower than 5.6, indicating considerable acid deposition. The pH of the surface water is generally higher than that of the atmospheric water. Factor analysis on the concentrations of the dissolved components suggests that the surface water chemistry depends principally on the chemistry of the atmospheric water. The dissolution of carbonate minerals and silicate-water interaction plays a rather minor role in affecting the water chemistry. δ 18 O and δD of all the natural water samples align fairly well along the global meteoric water line. The δ 34 S of the dissolved SO4 in the meteoric water has values ranging from 3.4 to 8.2‰, showing little seasonal difference. The contribution from sea-salt to the total atmospheric S is estimated to be less than 10%. The δ 34 S of the anthropogenic S in the Chuncheon atmosphere is calculated to be 2.5 to 7.2‰, which partly overlaps the reported values of S in Chinese coal, Chinese rainfall, and Japanese fallout. Appropriate tracking and quantitative estimation of the contribution from possible pollution sources to the local S concentrations requires more information on the isotopic compositions of the potential pollution sources. The δ 34 S of the dissolved SO4 in the surface water has values ranging from 3.2 to 6.2‰, which is a little narrower than that of the meteoric water. The δ 34 S and the concentration range of the dissolved SO4 in the stream water, the results from factor analysis on the compositional variables, and observations from geological field work suggest that most SO4 comes from the meteoric input, and that the δ 34 S of the surface water may be utilized for the investigation of tracing and identifying the sources of the atmospheric pollutant S in the study area.

The hydrogeochemistry of the Lac du Bonnet granitic batholith has been determined for the region of the Whiteshell Research Area (WRA) in southeastern Manitoba, Canada. This work forms part of the geosciences studies performed for the Canadian Nuclear Fuel Waste Management Program over the period 1980–1995 by Atomic Energy of Canada Limited (AECL). Knowledge of the variation of groundwater chemistry and its causes is useful in assessing the performance and safety of a nuclear fuel waste vault located at depths of up to 1000 m in a crystalline rock formation of the Canadian Shield. Groundwaters and matrix pore fluids have been obtained by standard sampling methods from shallow piezometers in clay-rich overburden, from packer-isolated borehole zones intersecting fractures or fault zones in the bedrock, and from boreholes in unfractured rock in AECL's Underground Research Laboratory (URL). Eighty-six individual fracture groundwaters have been sampled and analysed from permeable zones in 53 boreholes drilled to depths of up to 1000 m in the Lac du Bonnet batholith. In addition, 28 groundwaters from piezometers in a large wetland area near the URL have been sampled and analysed to determine the influence of clay-rich overburden on the bedrock hydrogeochemistry. Analyses have been made for major and minor ions, pH, Eh, trace metals, and stable and radioactive isotopes, to characterise these groundwaters and relate them to their hydrogeologic regimes. Shallow groundwaters in the fractured bedrock are generally dilute (TDS 500 m), Na–Ca–Cl–SO4 waters of increasing salinity (up to 50 g/l) with depth are found and in some fractures the waters have evolved to a Ca–Na–Cl composition. Isotopic data indicate that these waters are warm-climate and pre-glacial in origin, with residence times of over 1 Ma. Pore fluids observed to drain from the unfractured rock matrix in the URL facility are almost pure Ca–Cl in composition, ∼90 g/l salinity, and have a 2H/18O composition displaced well to the left of the global meteoric water line, about which all other WRA groundwaters lie. This information indicates that these pore fluids have undergone prolonged water-rock interaction and have residence times of 101–103 Ma. Most of the deeper fracture groundwaters and pore fluids have low Br/Cl ratios and moderate to high δ34S values of dissolved SO4 which indicates that their salinity could be derived from a marine source such as the basinal sedimentary brines and evaporites to the west of the batholith. These fluids may have entered the batholith during early Paleozoic times when sedimentary rocks were deposited over the granite and were driven by a hydraulic gradient resulting from higher ground in western Canada. The hydrogeochemical data and interpretations show that below ∼500 m in the WRA, fracture-hosted groundwaters are very saline, reducing and old, and are, therefore, indicative of stagnant conditions over the period of concern for nuclear waste disposal (1 Ma). The intact rock matrix at these depths is extremely impermeable as indicated by the presence of pore fluids with unusual geochemical and isotopic characteristics. The pore fluids may represent basinal brines that have evolved geochemically and isotopically to their current composition over periods as long as 103 Ma.

The stable isotope content of samples of precipitation and of the river water throughout the Piracicaba basin in Brazil was measured over a two-year period. The isotope values of precipitation follow a consistent pattern of relatively depleted values of both deuterium and oxygen 18 during the rainy summers and enriched ones during the dry winters, with all values aligned slightly above the Global Meteoric Water Line. The isotopic composition of the river water throughout the basin shows a remarkable spatial coherence and much smaller scatter of data than those of the precipitation. The isotope composition of river water is close to that of the precipitation in the rainy season, however, with a consistent lower d-excess value by 1/1000-2/1000. This is attributed to evaporative water loss in the basin, in part an expression of the recycling of water due to the anthropogenic activity in the region. The more divergent values are recorded during high-water stages in the rivers. In many cases, the floods during the beginning of the rainy season are characterized by an enrichment of the heavy isotopes and lower d-excess values when compared to the precipitation, with the opposite situation later in the rainy season. This is interpreted as resulting from the watershed/riverflow interaction pattern, and it thus suggests that the isotope composition can monitor the hydrologic situation in the basin and its changes.

This study investigated the composition of water co-produced with coalbed methane (CBM) from the Upper Cretaceous Ferron Sandstone Member of the Mancos Shale in east-central Utah to better understand coalbed methane reservoirs. The Ferron coalbed methane play currently has more than 600 wells producing an average of 240 bbl/day/well water. Water samples collected from 28 wellheads in three fields (Buzzards Bench, Drunkards Wash, and Helper State) of the northeast–southwest trending play were analyzed for chemical and stable isotopic composition. Water produced from coalbed methane wells is a Na–Cl–HCO3 type. Water from the Drunkards Wash field has the lowest total dissolved solids (TDS) (6300 mg/l) increasing in value to the southeast and northeast. In the Helper State field, about 6 miles northeast, water has the highest total dissolved solids (43,000 mg/l), and major ion abundance indicates the possible influence of evaporite dissolution or mixing with a saline brine. In the southern Buzzards Bench field, water has variable total dissolved solids that are not correlated with depth or spatial distance. Significant differences in the relative compositions are present between the three fields implying varying origins of solutes and/or different water–rock interactions along multiple flow paths. Stable isotopic values of water from the Ferron range from +0.9‰ to −11.4‰ δ18O and −32‰ to −90‰ δ2H and plot below the global meteoric water line (GMWL) on a line near, but above values of present-day meteoric water. Isotopic values of Ferron water are consistent with modification of meteoric water along a flow path by mixing with an evolved seawater brine and/or interaction with carbonate minerals. Analysis of isotopic values versus chloride (conservative element) and total dissolved solids concentrations indicates that recharge water in the Buzzards Bench area is distinct from recharge water in Drunkards Wash and is about 3 °C warmer. These variations in isotopes along with compositional variations imply that the Ferron reservoir is heterogeneous and compartmentalized, and that multiple flow paths may exist.

Composite monthly samples of atmospheric precipitation were collected over different periods of time ranging from one to seven years at 77 different locations throughout Italy. These samples were measured for their oxygen and hydrogen isotopic composition to obtain basic information for hydrological and meteorological studies in this area. On the basis of the results obtained a first map of the isotopic composition of precipitations in Italy has been drawn up. The main features of this map are the following: (1) no isotopic latitudinal gradient has been found along the Tyrrhenian coast from Sicily to the Italian–French border, despite the considerable range of latitude; (2) a minor latitudinal gradient is found in the southeasternmost section of the country (Apulia), partially favored by the local morphology; (3) a marked ‘shadow effect’ of the Apennines is apparent along the southern section of the Po valley and along the central section of the Adriatic coast; (4) the contribution of water vapor from the northernmost section of the Adriatic sea affects the eastern and central sections of the Po plain; (5) the shadow effect of the Alps is considerably smaller than expected; (6) the isotopic vertical gradients calculated in nine different areas and based on groups of two to five different stations vary but are essentially close to about −0.2‰/100 m; (7) when mean monthly temperature values were available, their relationship with the isotopic composition of precipitation was found to be, on average, very poor; (8) the relationship between mean δ18O and mean δD calculated for the collection locations shows shifts of both the slope and the deuterium excess when compared to the global meteoric water line. These shifts are different for northern, central, and southern Italy; (9) in a few cases anomalously low monthly δ values suggest the existence of pronounced ‘amount effects’.

Study of the Cenomanian–Turonian and Plio–Quaternary aquifers of Essaouira basin (Western Morocco), based on the interpretation of geochemical (major elements) and isotopic (18O, 2H, 13C and 14C) data, has aided the understanding of the hydrodynamics of these aquifers, which is greatly affected by tectonics. Hydrochemical characteristics based on the bivariate diagrams of major ions (Cl–, SO42–, NO3–, HCO3–, Na+, Mg2+, K+ and Ca2+) and electrical conductivity and mineral saturation indices indicate that the origins of groundwater mineralisation are the result of: (1) evaporite dissolution; (2) cation exchange reactions; (3) and evaporation processes. Radiogenic isotopes (3H and 14C) have highlighted the presence of significant recent recharge in the eastern part of the basin, with groundwater moving according to the general flow path (south-east to north-west). Stable isotope data from the Essaouira basin plot along the Global Meteoric Water Line and below the Local Meteoric Water Line. This suggests that groundwater has been recharged under several different climate regimes.

The isotopic composition ( d 18 O , d D ) of precipitation in the windward side of the Sierra Madre Oriental on the eastern flank of the Mexican Volcanic Belt was characterized along a 90 km transect from sea level up to an altitude of 4220 meters. Rain samples were collected during the rainy season (May through October) from 2007 through 2012. The Local Meteoric Water Line (LMWL), determined with linear regression of isotope results, is d D = 7.44 d 18 O + 7.3, R 2 = 0.99. This line departs from the Global Meteoric Water Line (GMWL) for precipitation at altitudes greater than 3000 masl due to deuterium enrichment processes. The results obtained in this research were compared with isotopic data of the Global Network of Isotopes Precipitation (GNIP) data base from the port of Veracruz. The altitude (Z) gradient of d 18 O was also determined by the linear regression of precipitation data, resulting in the relation d 18 O = -2.1Z - 5.56, R 2 = 0.86, where Z is altitude in kilometers. This implies a d 18 O vertical gradient of -0.21 / 100 m, which falls within the normal range described in the literature for tropical areas. Finally, the isotopic record of meteoric waters during the years of observation shows anomalous enrichment in d 18 O and d D at an altitude of about 1400 m, probably influenced by the local topography and/or an isotope effect related to tropical storms typical of this latitude. This characterization will increase the understanding of important hydrological processes and will provide a foundation for future hydrological research.

We report δ18O and δD stable isotope compositions of water collected at several sites in northern Death Valley, including the Salt Creek pupfish (Cyprinodon salinus M.) habitat in Mesquite Flat basin. Various theories exist concerning the source of water for Salt Creek, including snowmelt and precipitation, as well as contribution from ground-water. A comparison of Death Valley waters to the Global Meteoric Water Line indicated that none of the rain or snow samples are reasonable candidates for habitat source water; however, all of the ground-water sampled could serve as the source water for the progressively evaporating pupfish habitat sites.

The geochemical evolution of groundwaters along a 24 km flow beneath Central Mexico City path from the Sierra de las Cruces towards Lake Texcoco has been investigated using stable isotopes, radiocarbon and major and trace elements to determine the natural baseline conditions, the extent of any contamination and the effectiveness of the overlying aquitard seal. Modern groundwaters of low salinity ( −1 ) are found up to 11 km from the outcrop area and groundwater ages of up to 6000 yr bp occur in the middle part of the section. Groundwater stable isotope ratios δ 18 O and δ 2 H lie close to the global meteoric water line, indicating that the groundwater originates from local rainfall. The groundwater chemistry may be interpreted as the result of inputs from the source area with progressive water–rock interaction down the horizontal flow gradient. A redox boundary is found at 9 km along the line of section, coincident with the start of the confined section. Relatively low nitrate concentrations (below 9 mg l −1 NO 3 –N) are found in the aerobic waters; low concentrations of NO 3 in the aerobic waters and low Cl reflect inputs prior to the modern development. Some elements (Cr, U, As, Se, Sb) increase their concentration with distance (time) as far as the redox boundary, but low concentrations occur in the reducing aquifer section. The chemistry of several major ions (Mg, Na/Cl, K) as well as trace elements such as Li, Rb, Ba reflect the weathering of the basaltic mineral assemblage (feldspars and mafic minerals) and their increases are generally proportional to residence time; phosphate, F and I concentrations indicate a probable source from apatite in the basaltic or rhyolitic rocks. A borehole in the east of the city (some 17 km downgradient) intercepted thermal water (Si geothermometry indicates 163°C at depth). This water gives a distinctive composition indicating possible addition of metamorphic CO 2 which has then reacted with the igneous rocks. Increases in B and Cl are derived from volatiles trapped in the glass or vesicular basalt. A thermal anomaly found in the middle section of the heavily pumped aquifer is interpreted as the up-coming of warmer water from medium to greater depth mainly from basalts, rhyolites and possibly limestones. The geochemistry indicates that groundwater beneath Mexico City is of good quality and there is no obvious evidence of leakage of inorganic compounds from surface sources of contamination through the aquitard. The younger groundwater drawn from the western outcrop area is generally of good inorganic quality. Increased drawdowns in the confined aquifer have induced flow of warmer water with higher Cl from depth. The resources in the aquifer represent an important reserve of good quality water which need to be properly managed as a high quality resource as part of integrated plans for the City's future supplies.

Water movement through the soil-plant-atmosphere continuum can be tracked through its hydrogen and oxygen isotopic composition. How the isotopic composition of water evolves as it moves through this continuum provides critical information on ecosystem hydrology and climate change. Cryogenic vacuum extraction is the most applied method to extract waters from soil and plant material for such studies. However, recent experiments where oven dried soils were spiked with a reference water suggest potential for these techniques to bias results. We present results from a greenhouse-based plant water uptake and cryogenic vacuum distillation experiment using Salix viminalis cuttings. We tested the capacity for cryogenic vacuum extraction to recover irrigation water and the plant-available water pool from 4 soils that were subject to continuous irrigation as would occur in nature. Results show that δ2H and δ18O values of extracted soil waters reflect those of irrigation water, but with some influence of evaporation that varied with differences in soil humic and clay content. This suggests that isotope effects observed in laboratory experiments with oven-dried soils may not be relevant under natural conditions. Cryogenic vacuum extraction also recovered xylem water δ2H values that matched the δ2H values of extracted soil water but revealed small, consistent offsets between xylem and soil water δ18O values of 0.84 ± 1.13‰. Although these effects may not significantly bias water isotope sourcing applications, they do result in large extrapolation errors when estimating original source water isotope composition from extracted xylem waters using the back extrapolation to the global meteoric water line method.

Physical-chemical, chemical and isotopic data of spring water, groundwater and river water from the Actopan basin, central Veracruz were analyzed with the purpose of determining the origin and flow of groundwater. Spring water temperature between 9.6 °C and 18.3 °C, and low electrical conductivity ( 10 mg/L allow the identification of anthropogenic sources. Hydrogen and oxygen isotope results fit reasonable well with the Global Meteoric Water Line (GMWL, δ2H = 8 δ18O + 10) indicating that their recharge derives from local precipitation. On the basis of the observed isotope gradient with altitude (Z), (δ18O = -2.1 (Z km) - 5.56), three main groups of groundwater have been identified: 1) Evaporated water related to the precipitation in the dry season; 2) water, located on the line defined for the regional isotopic gradient, recharged during the rainy season; and 3) water recharged at levels slightly higher than its theoretical value of recharge, showing a component of deep flow and recharge from river water in the coastal plain.

Cellulose delta18O and deltaD can provide insights on climates and hydrological cycling in the distant past and how these factors differ spatially. However, most studies of plant cellulose have used only one isotope, most commonly delta18O, resulting in difficulties partitioning variation in delta18O of precipitation vs. evaporative conditions that affect leaf water isotopic enrichment. Moreover, observations of pronounced diurnal differences from conventional steady-state model predictions of leaf water isotopic fractionation have cast some doubt on single isotope modeling approaches for separating precipitation and evaporation drivers of cellulose delta18O or deltaD. We explore a dual isotope approach akin to the concept of deuterium-excess (d), to establish deuterium deviations from the global meteoric water line in leaf water (deltad(l)) as driven by relative humidity (RH). To demonstrate this concept, we survey studies of leaf water delta18O and deltaD in hardwood vs. conifer trees. We then apply the concept to cellulose delta18O and deltaD using a mechanistic model of cellulose delta18O and deltaD to reconstruct deuterium deviations from the global meteoric water line (deltad(c)) in Quercus macrocarpa, Q. robur, and Pseudotsuga menziesii. For each species, deltad(c) showed strong correlations with RH across sites. deltad(c) agreed well with steady-state predictions for Q. macrocarpa, while for Q. robur, the relationship with RH was steeper than expected. The slope of deltad(c) vs. RH of P. menziesii was also close to steady-state predictions, but deltad(c) were more enriched than predicted. This is in agreement with our leaf water survey showing conifer deltad(l) was more enriched than predicted. Our data reveal that applications of this method should be appropriate for reconstructing RH from cellulose delta18O and deltaD after accounting for differences between hardwoods and conifers. Hence, deltad(c) should be useful for understanding variability in RH associated with past climatic cycles, across regional climates, or across complex terrain where climate modeling is challenging. Furthermore, deltad(c) and inferred RH values should help in constraining variation in source water delta18O.

Summary The Diass horst aquifer system located 50 km east of Dakar (Senegal) is exploited in two main aquifers covered by a sandy superficial aquifer: the confined/unconfined Palaeocene karstic limestone and the confined Maastrichtian sandstone aquifer underneath. This system has experienced intensive groundwater abstraction during the last 50 years to supply increasing water demand, agricultural and industrial needs. The high abstraction rate from 1989 to 2009 (about 109,000 m 3 /d) has caused a continuous groundwater level decline (up to 30 m), a modification of the groundwater flow and salinization in parts of the aquifers. The objective of the study is to improve our understanding of the system functioning with regards to high pumping, identify the geochemical reactions that take place in the system, infer origin and timing of recharge by using mainly stable (δ 18 O, δ 2 H, 13 C) and radioactive ( 3 H and 14 C) isotopes. Water types defined in the Piper diagram vary in order of abundance from Ca–HCO 3 (65%), Ca/Na–Cl (20%), Na–HCO 3 (3%) and Na–Cl (12%). Values of δ 18 O and δ 2 H for the superficial aquifer range between −5.8 and −4.2‰ and between −42 and −31‰, respectively. For the Palaeocene aquifer they range from −5.8 to −5.0‰ and from −38 to −31‰, respectively; values in the Maastrichtian aquifer are between −5.9 and −4.3‰ for δ 18 O and −38 to −26‰ for δ 2 H. Plotted against the conventional δ 18 O vs δ 2 H diagram, data from the upper aquifer exhibit a dispersed distribution with respect to isotopic fractionation while those of the Palaeocene and Maastrichtian aquifers are aligned parallel and slightly below/or on the Global Meteoric Water Line (GMWL) evidencing ancient waters which had evaporated during infiltration. The low tritium (generally 14 C (0.7–57.2 pmc) contents indicate predominance of older water being recharged during the Pleistocene and Holocene periods. However, few boreholes which exhibit high tritium (1.2–4.3 TU) and 14 C (65.7–70.8 pmc) values indicate some mixture with recent water likely through faulting and vertical drainage from the upper to deeper aquifers as well as lateral flow along flow paths to the piezometric depressions created by pumping.

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 δ18O–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.

Analyses of environmental isotopes (18O, 2H, and 87Sr/86Sr) are applied to groundwater studies with emphasis on saline groundwater in aquifers in the Keta Basin, Ghana. The 87Sr/86Sr ratios of groundwater and surface water of the Keta Basin primarily reflect the geology and the mineralogical composition of the formations in the catchments and recharge areas. The isotopic compositions of 18O and 2H of deep groundwater have small variations and plot close to the global meteoric water line. Shallow groundwater and surface water have considerably larger variations in isotopic compositions, which reflect evaporation and preservation of seasonal fluctuations. A significant excess of chloride in shallow groundwater in comparison to the calculated evaporation loss is the result of a combination of evaporation and marine sources. Groundwaters from deep wells and dug wells in near-coastal aquifers are characterized by relatively high chloride contents, and the significance of marine influence is evidenced by well-defined mixing lines for strontium isotopes, and hydrogen and oxygen stable isotopes, with isotopic compositions of seawater as one end member. The results derived from environmental isotopes in this study demonstrate that a multi-isotope approach is a useful tool to identify the origin and sources of saline groundwater.

87Sr/86Sr, δD and δ18O together with chemistry of oilfield brines, were measured from Cambrian to Neogene strata in the Kuqa Foreland Basin, northwest China. The brines have87Sr/86Sr ratios ranging from 0.70944 to 0.71716, δD values from −33‰ to −67‰ and δ18O from −9.0‰ to 3.9‰. The most radiogenic87Sr brines have relatively heavy δ18O in the Cambro-Ordovician carbonates, and are suggested to originate from crystalline basement. δD and δ18O systematics show that all the brines slope to Global Meteoric Water Line, and intersect at δD=−60‰ and δ18O=−8.8‰, close to that of present-day local meteoric water, suggesting that meteoric water has mixed with evaporated ancient meteoric water. More saline samples have the lowest δD and δ18O contents and molar Na/Cl ratios of more than 0.9, resulting from salt dissolution.

The development and management of groundwater resources require an ability to understand and identify the recharge source to the groundwater system. Stable and radioactive isotope data have been used to investigate the source of recharge and the age of the shallow groundwater system within the southern Voltaian Sedimentary Basin (SVSB) of Ghana as part of an on going groundwater development project. The tritium concentrations in the groundwater samples are very low and range from less than 1–7.2 T.U., while measured 14C content ranges from 43 to 108% modern carbon. The tritium concentration of rainfall ranges from less than 1–4 T.U. The δ18O values of groundwater samples range from −4.2 to −2.6‰ while the δD values range from −21 to −10‰. Stable isotopic data of the groundwater samples lie either on or close to the global meteoric water line (GMWL) on the δD–δ18O plot and indicate that the shallow groundwater in the area is derived from meteoric water that has undergone no significant degree of kinetic evaporation during recharge. No indication of paleo recharge can be inferred from the 18O and 2H composition of the groundwater. Current tritium concentration in the groundwater is generally low, however, it proved useful in the qualitative identification of modern recharge. Radiocarbon-deduced ages range from about 3200±350 years B.P. to modern and indicate young recharge to the shallow groundwater system.

D/H studies of fluid inclusions of speleothems of the Soreq cave (Israel) are made using the method of vacuum thermal extraction. D/H measurements of present-day carbonate pool margins and waters show that the value of the vacuum thermal extraction fractionation Δex (=δDextracted water−δDcave water) is −30.0±1.4‰ for the Soreq cave deposits. D/H analyses of fluid inclusions of two fossil speleothems formed during periods equivalent to glacial times suggest that their isotopic compositions follow the global Meteoric Water Line (MWL) δ D– δ 18 O relationship, compared to present-day waters which follow the Mediterranean Meteoric Water Line (MMWL) trend. Two samples from interglacial periods show isotopic trends between these lines. These differences are presumed to reflect cooler less evaporative conditions in the Eastern Mediterranean Sea during glacial times.

This paper discusses the factors controlling the variations of heavy isotope contents of 57 rain events collected throughout the rain forest regions of Cameroon, Central Africa, during the great rainy season (August–November) of 1994. Our data display a wide range of values, from +1.69 to −10.80‰ for 18 O and from +23.2 to −85.5‰ for 2 H. The data follow closely the global meteoric water line suggesting that rain formation processes occurred under isotopic equilibrium conditions between both the condensate and the corresponding vapour. This also indicates that the observed heavy isotope contents have not been altered by evaporation during the descent of raindrops to the ground. The low heavy-isotope contents observed for some precipitation events are assumed to be controlled by the amount of rainfall and/or by the low condensation temperature. The former effect is related to the northward passage of the intertropical convergence zone (ITCZ) over the region under study, whereas the second effect is linked to high altitudes of condensation. Moreover, the latitudinal variations of the weighted mean 18 O contents indicates that in coastal areas (0–230 km inland from the Atlantic coast) the stable isotopic compositions of precipitation are controlled by a continuous extraction from the atmospheric reservoir of vapour as rains according to the Rayleigh distillation model, whereas at distances >230 km, recycling of continental moisture is thought to have influenced the isotopic compositions of rains.

Columnar and clear blocky calcite cement from a Middle Ordovician carbonate succession in east Tennessee is interpreted as meteoric in origin. Columnar and clear blocky calcite from this succession does not show extremely large 13C depletions reported from meteoric phases of younger rocks. Meteoric fluid δ18O values calculated from clear blocky calcite are ≅ 2 to 3‰ more negative than approximately coeval sea water; a relationship typical of modern, low-latitude, coastal meteoric water. Comparison with meteoric δ18O values from Ordovician units elsewhere suggests that the geographic distribution of these values may be broadly similar to that observed today. Therefore, we tentatively suggest that geographic distribution of meteoric δ18O values during both icehouse and greenhouse eras are similar.

Chemical data are used to clarify the hydrogeological regime in the Mafraq area in northern Jordan, as well as to determine the status of water quality in the area. Groundwater from the shallow aquifer in the Mafraq area can be divided into two major groups according to geographical locations and chemical compositions. Water in the basaltic eastern part of the study area is characterized by the dominance of chloride, sulfate, sodium, and potassium, whereas waters in the limestone aquifers in the west are dominated by the same cations but have higher concentrations of bicarbonate. Stable isotopes show that the shallow aquifers contain a single water type which originated in a distinct climatic regime. This water type deviates from the Global Meteoric Water Line (MWL), as well as from the eastern Mediterranean meteoric water line. The waters are poor in tritium, and thus can be considered generally older than 50 years. Chemical mass balance models suggest that water is moving from the west towards the north of the study area. This suggests that waters from the different basins are separated from each other. Degradation of water quality can be attributed to agricultural fertilizers in most cases, although the waste-water treatment plant at Khirbet es Samra is a contributor to pollution in the southwestern part of the study area.

A new δ18O map of southern Nevada groundwater shows a systematic decrease in δ18O of ∼5‰ from 36° to 39°N latitude. The variation is consistent with higher-latitude recharge following continuous flow paths along north-south trending graben valleys and systematically increasing in δ18O due to mixing with lower-latitude, higher-δ18O recharge. The data do not suggest that large masses of groundwater with unusually low δ18O values were recharged during the last pluvial period as suggested by previous workers. Many δ18O-δD pairs in groundwater indicate variable amounts of evaporation relative to the global meteoric water line. The precipitation rate and type (rain versus snow) for a given geographic area controls the extent of evaporation. A “model” δ18O value was calculated from evaporated groundwaters by subtracting postcloud evaporation. The distribution of these model δ18O values suggest new regional groundwater flow paths previously undocumented. Dissolved inorganic carbon in groundwaters collected from deep regional flow systems typically has low 14C concentrations (≤12% modern carbon). In contrast, groundwaters collected from the carbonate rock of the Spring Mountains and alluvium of Forty Mile Canyon have higher 14C contents, indicating more recent recharge. Because of nonlinear mixing of 14C, groundwater in the regional flow system likely acquired most of its observable 14C from mixtures of young, locally recharged groundwater.

We interpret oxygen and hydrogen isotope data for water samples from Lake Baikal, Siberia, its tributaries and other local rivers, and local precipitation in terms of the known water budget for the modern lake in order to gain insight into past limnological and climatic processes that influenced the lake. Lake Baikal is remarkably uniform in its isotopic composition @I80 = -15.8 +_ 0.2%0; 6D = - 123 f 2%0) and lies slightly to the right of the global meteoric water line, which suggests significant evaporation. Water is supplied to the lake by over 300 rivers and streams. The oxygen isotope values (8180) of the rivers in the Baikal catchment range from -13.4 to -21.2%0. The hydrogen isotope values (SD) for the same area range from - 103 to - 156%0. Both these ranges generally conform to the global meteoric water line. The weighted average isotopic composition of input to the lake (rivers plus precipitation) is -15.2%0 for 6’*0 and - 116%0 for 6D, values higher than those of the modern lake. Therefore, the isotopic composition of the modem lake cannot be related to the modern input through simple evaporation. Instead, modeling of the isotopic mass balance of the lake suggests that inputs (precipitation and influx from rivers) and outputs (evaporation and outflow) are not at a steady-state equilibrium under current climate conditions. We found previous input to the lake had lower ZY*O and 6D values than modern input, which reflects cooler climates in the past compared with modern conditions. Under constant climate conditions, steady-state conditions are not expected to be reached by the lake for at least 700 yr because of its large size and the long residence time of water in the lake.

Natural oxygen and hydrogen stable isotopes (δ18O-H2O and δD-H2O) in modern precipitation collected in five months event in 2001 in Northwestern Tunisia (El Kef area) are presented in this paper. The total correlation between δ18O and δD is obtained as the Global Meteoric Water Line and the Local Meteoric Water Line of the Tunis-Carthage. Seasonal variations of the precipitation D-excess provide more details for changes in moisture sources. The lower δD and δ18O values observed at the El Kef site reflect the combined effects of oceanic and sea vapor sources “Atlantic–Mediterranean origin”, fractionation due to local precipitation, and slower equilibration of the larger raindrops nucleated by a maritime aerosol.

Tritium and stable isotope (deuterium 2H and 18O) concentrations have been determined in natural waters collected from shallow lakes, wells, streams and rivers inside and in the vicinity of the former Semipalatinsk Nuclear Test Site (NE Kazakhstan). The Semipalatinsk Test Site (STS) was one of the main proving grounds for the testing of nuclear weapons by the former Soviet Union. Tritium activity concentrations have been determined by liquid scintillation counting, while hydrogen isotopic composition have been determined using a GV-Isoprime mass spectrometer coupled to an elemental analyzer. Tritium activity concentrations recorded in lake waters (in most cases >10 Bq L-1) were significantly higher than those in well, stream and the Irtysh River waters. In lake waters, enrichments in deuterium and 18O (δD and δ18O varying between –5 and –64 ‰ V-SMOW and –8.4 and +5.5 ‰ V-SMOW, respectively), and high salt concentrations, strongly suggest that significant evaporation has occurred. In contrast, deuterium and tritium signatures of common’ surface and underground waters at the STS were mostly typical of present-day isotope backgrounds of natural waters in NE Kazakhstan. In STS, come salt lakes like Bajansor and Tumatsor with elevated tritium activity from 12 to 15 Bq L-1 lie close to the Global Meteoric Water Line. The potential tritium source for these lakes is residual concentration of tritium after former nuclear test in STS. The study provides evidence to show that export of tritium from underground nuclear test areas and tritium enrichment produced by evaporation are both important determinants of tritium concentrations in standing waters on the Semipalatinsk test site.

The International Atomic Energy Agency (IAEA), in cooperation with the World Meteorological Organization (WMO), has been conducting a world-wide survey of hydrogen (H/'H) and oxygen (O/O) isotope composition of monthly precipitation since 1961. At present, 72 IAEA/WMO network stations are in operation. Another 82 stations belonging to national organizations continue to send their results to the IAEA for publication. The paper focuses on basic features of spatial and temporal distribution of deuterium and O in global precipitation, as derived from the IAEA/WMO isotope database. The internal structure and basic characteristics of this database are discussed in some detail. The existing phenomenological relationships between observed stable isotope composition of precipitation and various climate-related parameters such as local surface air temperature and amount of precipitation are reviewed and critically assessed. Attempts are presented towards revealing interannual fluctuations in the accumulated isotope records and relating them to changes of precipitation amount and the surface air temperature over the past 30 years.

▪ Abstract Changes of the isotopic composition of water within the water cycle provide a recognizable signature, relating such water to the different phases of the cycle. The isotope fractionations that accompany the evaporation from the ocean and other surface waters and the reverse process of rain formation account for the most notable changes. As a result, meteoric waters are depleted in the heavy isotopic species of H and O relative to ocean waters, whereas waters in evaporative systems such as lakes, plants, and soilwaters are relatively enriched. During the passage through the aquifers, the isotope composition of water is essentially a conservative property at ambient temperatures, but at elevated temperatures, interaction with the rock matrix may perturb the isotope composition. These changes of the isotope composition in atmospheric waters, surface water, soil, and groundwaters, as well as in the biosphere, are applied in the characterization of hydrological system as well as indicators of paleo-climatological conditions in proxy materials in climatic archives, such as ice, lake sediments, or organic materials.

The Stable Isotope Characteristics of Groundwater in the Voltaian Basin – An Evaluation of the Role of Meteoric Recharge in the Basin This study finds that groundwater recharge in the shallow aquifer system of the Voltaian Basin is recent meteoric water which has undergone evaporative enrichment of the heavier isotopes of the main components of the water molecule as it transits the vadose zone. Apparently, low annual relative humidities and high temperatures in the basin have led to lower slope and intercept of the Local Meteoric Water Line than is observed in the Global Meteoric Water Line. This assertion is consistent with the observation that annual relative humidity variations in the basin are in the range of 65% – 85% even during the rainy season. Surface flows are considerably enriched in terms of the heavier stable isotopes of oxygen and hydrogen, suggesting severe evaporation. Using the stable isotope data of the surface flows and the estimated isotopic signature of the most probable source rainwater, this study finds that the rate of evaporative losses of water from the surface waterbodies ranges between 29.5% and 84.7%.

International audience; Water stable isotopes and chloride profiles in pore-water through more than 800 m of sediments were obtained from a 2000 m-deep borehole (EST 433) drilled by Andra in the eastern Paris Basin. Vapour exchange method and aqueous leaching were used to obtain the stable isotope and chloride concentrations of pore-water from 24 rock samples. Petrophysical measurements included water contents, grain densities and porosities of the studied formations. Pore-water and some groundwater samples collected during the drilling are mainly of meteoric origin: they plot near the Global Meteoric Water Line, distributed between heavy-isotope depleted Oxfordian groundwater and enriched Triassic groundwater, in good agreement with previous data. The δ2H and δ18O values describe curved profiles in the Callovo-Oxfordian formation, and show an increase with depth below this formation (Dogger and Liassic). Similar trends were observed for the chloride concentrations, except in the Liassic formation where they are more or less constant. The low chloride concentrations in the basal Jurassic layers indicate that the source of salinity to the Dogger aquifer is likely the middle Liassic formation and not the Triassic salt as previously suggested. A preliminary modelling exercise showed that currently available diffusion parameters (diffusion coefficients and accessible porosities) might be used to properly simulate these exchanges for deuterium. This is not the case for chloride, perhaps because the used values for anion accessible porosity were not relevant and/or the applied modelling conditions were unsuitable.

Climatic warming from the late Paleocene into the early Eocene had profound effects on atmospheric and marine circulation, marine thermal gradients, and benthic biota. In addition, marine carbon isotope values decreased substantially in both surface and deep waters. Because carbon is rapidly exchanged between reservoirs at the earth's surface, such as marine surface water, the atmosphere, land plants, and materials that obtain carbon from plants (e.g., soil minerals and herbivores), carbon isotope fluctuations provide time lines linking the marine and continental records. We analyzed the carbon isotope composition of paleosol carbonates and mammalian tooth enamel from stratigraphic sections in northwestern Wyoming. Carbon isotope correlation demonstrates that a short interval of extreme high-latitude warming coincided precisely with the first appearance of several important modern mammalian orders. In addition, oxygen isotope analyses of fossils and paleosol carbonates provide information about climatic conditions on land in the Paleogene. We reconstructed the oxygen isotope composition of local meteoric water using biogenic minerals. Paleocene-Eocene meteoric water was significantly 18 O-depleted, indicating substantial loss of water vapor during its transport to the region. Soil temperature was calculated as a proxy for mean annual temperature, assuming oxygen isotope equilibrium between soil carbonate and meteoric water. Calculated temperatures were plausible (≈10–25°C), but highly variable, prohibiting high-resolution analysis of local temperature variations in response to global climatic warming.

We investigate the helium (He-3/He-4) and carbon (delta C-13) isotope compositions and relative abundance ratios (CO2/He-3) of gas samples together with the stable isotope compositions of dissolved carbon and sulfur and the oxygen and hydrogen isotopic compositions of the associated water phase from a number of geothermal fields located around Lake Van in eastern Anatolia, Turkey. The mantle-derived helium component, which is likely transferred to the crust beneath eastern Turkey by recent magmatism, is found to constitute up to 96% (e.g. Nemrut Caldera) of the total He content in fluids. As regards the spatial distribution of He, samples collected from areas of Pliocene-Quaternary volcanics are characterized by a wide and generally higher range of R/R-A ratios (0.93 to 7.76 R-A) compared to those of non-volcanic regions ((1.85 to 1.0 R-A). CO2/He-3 ratios vary over a wide range (2.4 x 10(5)-3.8 x 10(13)) but are mostly higher than that of the nominal upper mantle (similar to 2 x 10(9)). Oxygen-hydrogen isotope values of the waters are conformable with the Global Meteoric Water Line and indicate a local meteoric origin. Sulfate in waters is most probably derived from dissolution of marine carbonates and terrestrial evaporite units. Temperatures calculated by SO4-H2O isotope geothermometry lie between 40 and 199 degrees C, and are in poor agreement with reservoir temperatures estimated from silica geothermometers. Discordant temperatures may be due to either the relatively slow rate of isotopic equilibrium between water and sulfate or mixing of geothermal water with sulfate-bearing shallow waters which may modify the delta O-18 value. The delta C-13 (CO2) values of gas samples are consistently lower than those of their water counterparts, consistent with loss of CO2 from waters by degassing. Mixing between mantle and various crustal C-sources appears to be the main control on the C-isotope composition. The principal origin of CO2 in all samples is crustal lithologies, mainly limestone (similar to 85 to 98% of the total carbon inventory): thus, the crustal carbon flux is at least 10 times that from the mantle. There is a broad correlation between high He-3/He-4 values and thinner crust in the western part of the Lake Van region, where several historically-active volcanoes are located. This observation indicates that localized volcanic and magmatic activity exerts the primary control on the balance between mantle and crustally-derived volatiles in the region. (C) 2012 Elsevier B.V. All rights reserved. We investigate the helium (3He/4He) and carbon (δ13C) isotope compositions and relative abundance ratios (CO2/3He) of gas samples together with the stable isotope compositions of dissolved carbon and sulfur and the oxygen and hydrogen isotopic compositions of the associated water phase from a number of geothermal fields located around Lake Van in eastern Anatolia, Turkey. The mantle-derived helium component, which is likely transferred to the crust beneath eastern Turkey by recent magmatism, is found to constitute up to 96% (e.g. Nemrut Caldera) of the total He content in fluids. As regards the spatial distribution of He, samples collected from areas of Pliocene–Quaternary volcanics are characterized by a wide and generally higher range of R/RAratios (0.93 to 7.76 RA) compared to those of non-volcanic regions (0.85 to 1.0 RA). CO2/3He ratios vary over a wide range (2.4×105–3.8×1013) but are mostly higher than that of the nominal upper mantle (~2×109). Oxygen–hydrogen isotope values of the waters are conformable with the Global Meteoric Water Line and indicate a local meteoric origin. Sulfate in waters is most probably derived from dissolution of marine carbonates and terrestrial evaporite units. Temperatures calculated by SO4–H2O isotope geothermometry lie between 40 and 199°C, and are in poor agreement with reservoir temperatures estimated from silica geothermometers. Discordant temperatures may be due to either the relatively slow rate of isotopic equilibrium between water and sulfate or mixing of geothermal water with sulfate-bearing shallow waters which may modify the δ18O value. The δ13C (CO2) values of gas samples are consistently lower than those of their water counterparts, consistent with loss of CO2from waters by degassing. Mixing between mantle and various crustal C-sources appears to be the main control on the C-isotope composition. The principal origin of CO2in all samples is crustal lithologies, mainly limestone (~85 to 98% of the total carbon inventory): thus, the crustal carbon flux is at least 10 times that from the mantle. There is a broad correlation between high3He/4He values and thinner crust in the western part of the Lake Van region, where several historically-active volcanoes are located. This observation indicates that localized volcanic and magmatic activity exerts the primary control on the balance between mantle and crustally-derived volatiles in the region.

Museum collections contain a wealth of insect remains originating from a wide geographic range, which can be used to investigate their utility as a proxy for environmental isotope ratios. Chitinous remains of insects such as beetles (Coleoptera) are chemically stable and their stable isotope composition is strongly related to that of environmental water in the period of cuticle formation. We present a dataset of chitin δD and δ18O in two genera of water beetles from a museum collection containing 40 locations for Helophorus (water scavenging beetles) and 48 locations for Hydroporus (predaceous diving beetles) that were selected from latitudes 27–82°N in North America. Only two genera were used to minimize inter-sample variation caused by species-specific differences in metabolic effects, feeding strategy, habitat, and life cycle. The isotopic composition of water beetle exoskeletons had a strong latitudinal trend (North–South) from −160 to +65 ‰ for δD and from 7 to 34 ‰ for δ18O, paralleling gradients of isotopes in precipitation. Strong relationships were observed between isotopic composition of beetles and modelled July precipitation (0.71 < R2 < 0.82, p < 0.001). The relationship between δD and δ18O in the beetle samples had a systematic offset from the global meteoric water line, which was likely caused by metabolic effects during chitin formation. The offset between δD values in beetles and in modelled precipitation was 33 ‰ larger, on average, for Hydroporus compared with Helophorus, suggesting fractionation of hydrogen isotopes during passage through the food chain. This trophic level effect was not observed for stable oxygen isotopes. Furthermore, the observed deviations between isotopic composition of water beetles and modelled precipitation at collection sites were not constant and indicated local hydrological deviations from modelled precipitation. The largest deviations were observed for sites in the Southern US and the Arctic that are highly evaporative and at sites in the Rocky Mountains and Coastal Mountains that were fed by snow melt. Our results indicated that the isotopic composition of water beetles from a museum collection was systematically related to δD and δ18O values of precipitation at the collection site.

The stable water isotopes H218O and HDO are incorporated as passive tracers into the oceanic general circulation model MPI-OM, and a control simulation under present-day climate conditions is analyzed in detail. Both δ18O and δD distributions at the ocean surface and deep ocean are generally consistent with available observations on the large scale. The modelled δD-δ 18O relations in surface waters slightly deviates from the slope of the global meteoric water line in most basins, and a much steeper slope is detected in Arctic Oceans. The simulated deuterium excess of ocean surface waters shows small variations between 80° S and 55° N, and a strong decrease north of 55° N. The model is also able to capture the quasi-linear relationship between δ18O and salinity S, as well as δD and S, as seen in observational data. Both in the model results and observations, the surface δ−S relations show a steeper slope in extra-tropical regions than in tropical regions, which indicates relatively more addition of isotopically depleted water at high latitudes.