Mediterranean Meteoric Water Line Research Articles

Eastern Mediterranean climate change deduced from the Soreq Cave fluid inclusion stable isotopes and carbonate clumped isotopes record of the last 160 ka

A fundamental issue in the interpretation of speleothem calcite δ18Occ records is the correct partitioning of the effects of temperature and water δ18O variations. This study explores the paleo-environmental evolution of the Eastern Mediterranean Sea (EMS) region using Soreq Cave speleothems in the last 160 ka, a period covering glacial MIS6 to the present, through the independent determinations of temperatures via carbonate clumped isotopes (Δ47) and fluid inclusion δ18Ow, δDw and d-excess values of cave water entrapped in the speleothems. The observed general agreement between the trends in water δ18Ow composition directly measured from fluid inclusions and calculated from Δ47 temperatures and δ18Occ support the robustness of the data. Δ47 temperatures, derived using a revised thermometer calibration that includes recent modifications in 17O correction, vary from high values of 20–22 °C during interglacial periods to low values of 11–12 °C in cold glacial and stadial periods. Temperatures of 19–22 °C are observed during the time of deposition in the EMS of sapropel S5 in the last interglacial MIS5e period and sapropel S1 in the early Holocene, immediately following Terminations II and I, respectively. The Soreq Cave Δ47 temperatures generally agree with previously estimated EM sea surface temperatures, in support of the absence of a significant land-sea temperature gradient. Cave water δ18Ow values show large variations (from ∼-3 to −7.5‰), with high glacial and low interglacial values. These variations are largely explained by changes in Mediterranean Sea water composition due to glacial ice melting and freshwater input during sapropel periods, combined with the effect of rainfall amounts during interglacial periods. An analysis of relative timing shows that temperature rise precedes hydrological changes in the initial stages of Termination events. Fluid inclusion d-excess values show clear variations between values similar to the Global Meteoric Water Line during cold periods and values similar to the local Eastern Mediterranean Meteoric Water Line (EMMWL) in warm periods.

Geochemical characterisation of the thermo-mineral waters of Greece.

Geothermal areas of Greece are located in regions affected by recent volcanism and in continental basins characterised by elevated heat flow. Many of them are found along the coast, and thus, water is often saline due to marine intrusion. In the current study, we present about 300 unpublished and literature data from thermal and cold mineral waters collected along Greece. Samples were analysed for major ions, Li, SiO2 and isotopes in water. Measured temperatures range from 6.5 to 98 °C, pH from 1.96 to 11.98, while Total Dissolved Solutes (TDS) from 0.22 to 51 g/L. Waters were subdivided into four main groups: (1) thermal; (2) cold; (3) acidic (pH < 5); and (4) hyperalkaline (pH > 11). On statistical basis, thermal waters were subdivided into subgroups according to both their temperature [warm (< 29 °C), hypothermal (29–48 °C), thermal (48–75 °C) and hyperthermal (> 75 °C)] and TDS [low salinity (< 4 g/L), brackish (4–30 g/L) and saline (> 30 g/L)]. Cold waters were subdivided based on their pCO2 [low (< 0.05 atm), medium (0.05–0.85 atm) and high (> 0.85 atm)]. δ18O–H2O ranges from − 12.7 to + 2.7‰ versus SMOW, while δ2H–H2O from − 91 to + 12‰ versus SMOW being generally comprised between the Global Meteoric Water Line and the East Mediterranean Meteoric Water Line. Positive δ18O shifts with respect to the former are mostly related to mixing with seawater, while only for a few samples these shifts point to high-temperature water–rock interaction processes. Only a few thermal waters gave reliable geothermometric estimates, suggesting reservoir temperatures between 80 and 260 °C.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10653-021-01001-1.

An overview of the atmospheric moisture transport effect on stable isotopes (δ18O, δ 2H) and D excess contents of precipitation in Iran

Iran faces a water shortage crisis due to its long and frequent droughts and rapid population growth. In this study, moisture sources have been determined in 161 precipitation events from 12 stations using a Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model. Ten main moisture sources have been identified among which the Persian Gulf and the Persian Gulf with terrestrial sources are dominant. Backward trajectory outputs demonstrate that the precipitation events in the stations in the north of Iran originate mostly from the Caspian Sea and terrestrial sources. These precipitation events are mostly plotted on the Global Meteoric Water Line (GMWL) or between GMWL and Eastern Mediterranean Meteoric Water Line (EMMWL). Precipitation events in the middle and south of Iran stations receive moisture mostly from the Persian Gulf and terrestrial sources and they are mostly plotted on EMMWL. Linking backward trajectory models with precipitation events (δ 18O and δ 2H) determines the general isotope characteristics of each moisture source. Most of the precipitation events originate from high sea surface temperature (SST) water bodies and are plotted on EMMWL. However, precipitation events originating from lower SST water bodies are mostly plotted on GMWL and between GMWL and EMMWL. Plotting the average (δ 18O and δ 2H) in the studied stations on the meteoric water lines of the regions located on the dominant air masses trajectories toward Iran confirms the dominant moisture sources for the studied stations and also other obtained results by stable isotope technique and HYSPLIT model in this study.

A new approach to Kırşehir (Turkey) geothermal waters using REY, major elements and isotope geochemistry

Kirsehir geothermal area is located in Central Anatolia and is controlled mainly by NW–SE and NE–SW faults belonging to Seyfe Fault Zone. This paper examines the geochemistry, particularly trace elements and isotopes of geothermal fluids in relation to regional tectonics and discusses the geothermal potential of the Kirsehir. The cold and thermal fluids forming the Kirsehir sources are Ca–Mg–HCO3 and Ca–Na–HCO3–Cl, respectively. According to Giggenbach diagram, the cold waters are located in the partially equilibrated water region whilst other samples are located in the immature water region. Besides, the semi-logarithmic Schoeller diagram shows that cold and hot waters come from different aquifers because cold and thermal fluids exhibit similar ion concentrations in themselves. Cation and SiO2 geothermometers show that the reservoir rock temperatures range from 58 to 98 °C. According to δ18O and δ2H values, the thermal fluids in the study area are located between the Mediterranean meteoric water line and global meteoric water line; this suggests that the geothermal sources are of meteoric origin and the colder aquifers are recharged by precipitation at lower attitudes, whereas the geothermal reservoir is recharged by precipitation at higher altitudes and from inland environments. The Rare Earth Elements and Yttrium results show that the waters have remarkable negative Cerium (Ce), Europium (Eu) and Yttrium (Y) anomalies. The negative Ce anomaly indicates that the colder aquifers of Kirsehir are close to oxygen-rich surface waters and thermal fluids interact with granites. The Eu anomalies in groundwater are controlled by the preferential mobilization of Eu2+ during water–rock interaction compared to Eu3+ and negative Eu anomalies, which show that geothermal fluids have leached from granites. Y/Ho values between 25 and 33 of the thermal fluids at Kirsehir result from the active contribution of fluorine during mobilization of REE as either fluoride or fluorocarbonate ligand complexes, causing Y to act as a heavy pseudolanthanide.

Assessment of interconnection between surface water and groundwater in Sawa Lake area, southern Iraq, using stable isotope technique

Interaction between surface water represented by the Euphrates River, natural springs, and Sawa Lake with groundwater (11 wells) in southern Iraq was investigated in this study. Water samples were collected for hydrochemistry and stable isotope (2H and 18O) analysis. Sampling of water from determined stations (10 stations along the Euphrates, 3 springs, and Sawa Lake) were carried out during two stages; the first was in October 2013(dry season) and the second one was in March 2014 (wet season). The aim of the research is to assess the interaction of groundwater–surface water, which includes Al-Atshan River (branch of the Euphrates River), Sawa Lake, and the groundwater in the study area by using hydrochemistry and stable isotope techniques. The results indicate that surface waters have a different type of water from that of groundwater. In δ 2H and δ 18O diagrams, all groundwater, springs, and Sawa Lake waters are plotted below the Global Meteoric Water Line (GMWL) and the local meteoric water line (LMWL) indicating the influence of evaporation processes and seasonal variation. The LMWL deviates by a d-excess about +13.71 toward the East Mediterranean meteoric water line (EMWL) indicating that the origin of the vapor source is the Mediterranean Sea. The river water has different isotopic compositions from that of groundwater, springs, and Sawa Lake. The final conclusion is that there is no clear influence of the groundwater on the river water while there is an intermixing between the groundwater in the different locations in the study area.

Qualitative spring water management in the central western catchment of the West Bank from hydrochemical and environmental isotopes approaches

This study assesses spring water quality data connected to groundwater pollution indicators for building a qualitative groundwater management system in the central western catchment of the West Bank. It characterizes the major ion chemistry and trace elements for the mountainous spring water in terms of their suitability for irrigation and domestic purposes. The results increase community awareness about qualitative access to available and reliable water resources in central catchments. The cation–anion orders indicate calcium–hydrogen carbonate spring water type, useful for determining the parameters of risk. EC-TDS relations classified the water as fresh and within the allowable limits of the WHO guidelines. The fact that the majority of these springs are located within densely populated areas explains the higher counts of total and fecal coliforms. The environment of recharge is determined through the stable isotopic compositions of deuterium and oxygen—18 of a north–south profile analysis. The study shows that the isotopic composition, ranging from −5.06 to −5.89 ‰ for δ18O and from −20.28 to −24.44 ‰ for δ2H. The δ2H–δ18O relationship is used to define the local meteoric water line (LMWL), according to the equation: δ2H = 4.7 δ18O + 3.6. The plotted isotopic content of the analyzed water samples on the Mediterranean meteoric water line signifies water recharge from recent precipitation.

Isotope Geochemistry of Groundwater from Fractured Dolomite Aquifers in Central Slovenia

The hydrogeochemistry and isotope geochemistry of groundwater from 85 wells in fractured dolomite aquifers of Central Slovenia were investigated. This groundwater represents waters strongly influenced by chemical weathering of dolomite with an average of δ13CCARB value of +2.2 ‰. The major groundwater geochemical composition is HCO3 − > Ca2+ > Mg2+. Several differences in hydrogeochemical properties among the classes of dolomites were observed when they were divided based on their age and sedimentological properties, with a clear distinction of pure dolomites exhibiting high Mg2+/Ca2+ ratios and low Na+, K+ and Si values. Trace element and nutrient concentrations (SO4 2−, NO3 −) were low, implying that karstic and fractured dolomite aquifers are of good quality to be used as tap water. Groundwater was generally slightly oversaturated with respect to calcite and dolomite, and dissolved CO2 was up to 46 times supersaturated relative to the atmosphere. The isotopic composition of oxygen (δ18OH2O), hydrogen (δDH2O) and tritium ranged from −10.3 to −8.4 ‰, from −68.5 to −52.7 ‰ and from 3.5 TU to 10.5 TU, respectively. δ18O and δD values fell between the GMWL (Global Meteoric Water Line) and the MMWL (Mediterranean Meteoric Water Line) and indicate recharge from precipitation with little evaporation. The tritium activity in groundwater suggests that groundwater is generally younger than 50 years. δ13CDIC values ranged from −14.6 to −9.3 ‰ and indicated groundwater with a contribution of degraded organic matter/dissolved inorganic carbon in the aquifer. The mass balances for groundwater interacting with carbonate rocks suggested that carbonate dissolution contributes from 43.7 to 65.4 % and degradation of organic matter from 34.6 to 56.3 %.

New Approach for the Analysis of Isotopic Composition in Precipitation Globally

Isotopic composition of hydrogen and oxygen of water in precipitation is important tool to analyze the water in hydrological cycle. A new method has been suggested by Singh [7] plotting slope versus intercept of Local Meteoric Water Line (LMWL) to find the original isotopic composition in precipitation as injected tracer globally. Singh [8-10] has applied these concepts to analyze the isotopic composition in precipitation in different catchment areas of river and different seasons, precipitation falling at different altitudes in a region or a place and across the continent. These studies are extended for the (a) study of changing intercept but keeping the same slope as attributed to changed conditions as the source of atmospheric moisture. The experimental data as available of two transect from Amazon to Altiplano in South America are analyzed. The results are presented assigning two components, one due to Rayleigh adiabatic condensation process rainfall and second recycled water vapour by evotranspiration. The details of the analysis are given and the results clearly indicate these two components, are discussed in detail. (b) Study of higher intercept due to Mediterranean Meteoric Water Line (MMWL), Israel samples from various inputs on mountains, coastal area, caves and valley to ascertain the precipitation is from the same source. (c) Study of LMWL across the country (India) for four different regions to obtain the LMWL of the regions by the method of Singh [7] obtained the original isotopic composition of water in all the four regions thereby get the Global Meteoric Water Line (GMWL).

Environmental Isotopic Characterization of Groundwater and Surface Water in Northeast Missan Province, South Iraq

AbstractThe present work studies the environmental isotopes assess groundwater characteristics of the different parts of the main aquifer in the northeast Missan Province in south of Iraq. Water samples of groundwater and surface water were collected for two dry and wet seasons during the water year of 2011–2012. The study shows that most of the groundwater in the aquifer falls above the global meteoric water line, and all the samples fall below the Mediterranean meteoric water line, indicating that these samples are a mixture of two water types. The tritium content of these samples supports this conclusion. The overall conclusion of this study indicates that there are two sources of groundwater recharge in the studied area: the ephemeral streams (Teeb and Dewerge) and major precipitation sources. According to the tritium levels at or below one tritium unit (TU) obtained from the water, supply wells are highly confined or “not vulnerable”. Overall, the 3H results imply that recent recharge has taken place during the last four to five decades. In the recharge area, the high tritium content in the southern part of the Teeb area suggests that the recharge originates from rapid infiltration of surface runoff. Therefore, the groundwater resources in the study area should be protected from contamination, because it will influence the aquifer in a relatively short period of time if any contamination enters the recharge areas of the aquifer.

A late Holocene climate record in stalagmites from Modrič Cave (Croatia)

AbstractFew terrestrial Holocene climate records exist from south‐eastern Europe despite its important geographical position as a transitional climatic zone between the Mediterranean and mainland continental Europe. Here we present new petrographic and stable isotope data for two Holocene speleothems from Modrič Cave, Croatia (44°15′N, 15°32′E), a coastal Adriatic site (120 m inland). Modern meteorological and cave conditions have been monitored for 2 years to understand the links between climate variability and stable isotope time‐series records in speleothems. Typical of a Mediterranean‐type climate, a negative water balance exists between April and September, so that recharge of the aquifer is restricted to the winter months. The weighted mean δ18O of the rainfall is −5.96‰ (2σ = 2.83), and the weighted mean D/H rainfall value is −36.83‰ (2σ = 19.95), slightly above the Global Meteoric Water Line, but well below the Mediterranean Meteoric Water Line. Modern calcite from the tops of each stalagmite exhibits δ18O values that are close to isotopic equilibrium with their respective drip water values. Unfortunately, the relatively young ages and low uranium contents (ca. 50 p.p.b.) of both stalagmites hamper the use of U‐series dating. Radiocarbon dates have been used instead to constrain their chronology using a dead carbon correction. Apart from some Isotope Stage 3 material (ca. 55 ka), both stalagmites were deposited during the late Holocene. Climatic conditions during the late Holocene are inferred to have been sufficiently wet to maintain stalagmite growth and any hiatuses appear to be relatively short lived. Inferred changes in the stalagmite diameters during deposition are linked to δ13C and δ18O variations, indicating alternating periods of drier and wetter conditions. Drier conditions are inferred for the late Roman Ages warm period and the mid‐Medieval Warm Period. Wetter conditions are associated with the Little Ice Age. Copyright © 2012 John Wiley &amp; Sons, Ltd.

The record of temperature, wind velocity and air humidity in the δ D and δ 18O of water inclusions in synthetic and Messinian halites

Deuterium and oxygen isotope fractionations between liquid and vapor water were experimentally-determined during evaporation of a NaCl solution (35 g L −1) as a function of water temperature and wind velocity. In the case of a null wind velocity, slopes of δ D–δ 18O trajectories of residual waters hyperbolically decrease with increasing water temperatures in the range 23–47 °C. For wind velocities ranging from 0.8 to 2.2 m s −1, slopes of the δ D–δ 18O trajectories linearly increase with increasing wind velocity at a given water temperature. These experimental results can be modeled by using Rayleigh distillation equations taking into account wind-related kinetics effects. Deuterium and oxygen isotope compositions of water inclusions trapped by the precipitated halite crystals were determined by micro-equilibration techniques. These isotopic compositions accurately reflect those of the surrounding residual waters during halite growth. Isotopic compositions of water inclusions in twenty natural halites from the Messinian Realmonte mine in Sicily suggest precipitation temperatures of 34 - 4 + 10 ° C that match the homogenization temperatures obtained by microthermometry (median = 34 ± 5 °C). The similarity between the measured and experimental slopes of the δ D–δ 18O evaporation trajectories suggests that the effect of wind was negligible during the genesis of these halite deposits. Hydrogen and oxygen isotope compositions of water inclusions from Realmonte halite also define a linear trend whose extrapolation until intersection with the Mediterranean Meteoric Water Line allows the characterization of the water source with δ D and δ 18O values of −70 ± 10‰ and −11.5 ± 1.5‰, respectively. These results reveal that the huge amounts of salts deposited in Sicily result from the evaporation of seawater mixed with a dominant fraction (⩾50%) of meteoric waters most likely deriving from alpine fluvial discharge.

Hydrogeochemistry and pollution assessment of quaternary–tertiary aquifer in the Liwa area, United Arab Emirates

This study presents the data on the hydrochemical characteristics and isotope chemistry of Liwa aquifer, which could be useful to clarify the hydrochemical facies and hydrogeological regime in the study area. Electric conductivity and total dissolved solid values show that the investigated water is slightly brackish, due to the effect of evaporation and the occurrences of evaporite rocks in the adjacent Sabkhas of Abu Dhabi. Major cations and anions arranged according to their decreasing concentrations are: Na+ > Ca+2 > K+ > Mg+2 and Cl− > HCO3− > SO4−2, respectively. As sodium is the dominate cation and chloride is the prevailing anion, hydrochemically the groundwater of Liwa can be classified as Na–Cl rich, predominantly chloridic. Ion concentrations increase towards the northeast and presumably coincide with the lithological sources of ions. Factors affecting the hydrochemistry of the groundwater of the investigated area include the effect of weathering of soil and rocks, evaporation and agricultural activities. Stable isotopes of oxygen and hydrogen show that the shallow aquifers contain a single water type that originated in a distinct climatic regime. This water type deviates from the local meteoric water line, as well as from the Eastern Mediterranean Meteoric Water Line, suggesting potential evaporation of recharged water prior to infiltration. The waters are poor in tritium, and thus can be considered generally as indication for recharge prior to 1952. The degradation of groundwater quality can be attributed to evaporation and agricultural practices in most cases.

Hydrogeochemistry and Geothermometry of Thermal Groundwater from the Gulf of Suez Region, Egypt

The combined chemical composition, O and H isotopes, and the basic geologic setting of the geothermal system of the Gulf of Suez, Egypt have been investigated to evaluate the origin of the dissolved constituents and subsurface reservoir temperatures. Hydrochemical characterization of thermal waters discharged from springs and flowing artesian wells in the Gulf of Suez region show that there are two groups. One is Hammam Faroun thermal waters with salinity values exceeding 10,000 mg/l, discharge temperatures reach to 70oC, and Na-Cl hydrochemical facies. The other group is thermal waters discharged at Hammam Mousa, Ain Sukhna, and shallow flowing artesian wells at Ayoun Mousa and Ras Sudr. They are characterized by salinity values less than 10,000 mg/l, discharge temperatures ranging from 32.5 to 72oC and Na-Mg-Ca-Cl (Hammam Mousa), Na-Cl-SO4 (Ain Sukhna), and Na-Ca-Cl (Ayoun Mousa-2 well and Ras Sudr-2 well) water types. Different graphical presentations using major and minor ions indicated that little mixing with sea water is probably a source of dissolved constituents. Water/rock interaction is also a major source for the dissolved constituents as revealed from Ca and HCO3 enrichment of the thermal waters that is attributed to dissolution of carbonate minerals. Thermal waters from Hammam Faroun and Ras Sudr-2 well have the highest discharge temperatures and SiO2 concentrations that indicate that ascending hot water at the Hammam Faroun area is slightly mixed with cold water. The thermal waters from the study area are depleted in 18 O and 2 H and fall on the Global Meteoric Water Line (GMWL) and below the local eastern Mediterranean Meteoric Water Line (MMWL) with d-excess values ranging between 3.42 and 10.6‰, which is similar to the groundwater of the Nubian aquifer in central Sinai and the Western Desert of Egypt and suggesting a common origin. This indicates that these waters are paleo-meteoric water which

Impact of human activities on quality and geochemistry of groundwater in the Merdja area, Tebessa, Algeria

Chemical data are used to clarify the hydrogeological regime in the Merdja area in Tebessa, as well as to determine the status of water quality in this area. Groundwater from the aquifer in the Merdja area can be divided into two major groups according to geographical locations and chemical compositions. Water in the center part of the area of study 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 Tebessa 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 Mediterranean meteoric water line. The water is poor in tritium, and thus can be considered generally older than 50 years. Piezometric map suggests that water is moving from the west towards the center of the studied area, and from east towards center. Degradation of water quality can be attributed to agricultural fertilizers in most cases, although the wadi El Kebir River is a contributor to pollution in the middle part of the studied area.

Helium–carbon relationships in geothermal fluids of western Anatolia, Turkey

We investigate the helium, carbon and oxygen–hydrogen isotopic systematics and CO 2/ 3He ratios of 8 water and 6 gas samples collected from 12 geothermal fields in western Anatolia (Turkey). 3He/ 4He ratios of the samples ( R) normalized to the atmospheric 3He/ 4He ratio ( R A = 1.39 × 10 − 6 ) range from 0.27 to 1.67 and are significantly higher than the crustal production value of 0.05. Fluids with relatively high R / R A values are generally found in areas of significant heat potential (Kızıldere and Tuzla fields). CO 2/ 3He ratios of the samples, ranging from 1.6 × 10 9 to 2.3 × 10 14, display significant variation and are mostly higher than values typical of an upper mantle source (2 × 10 9). The δ 13C (CO 2) and δ 13C (CH 4) values of all fluids vary from − 8.04 to + 0.35‰ and − 25.80 to − 23.92‰ (vs. PDB), respectively. Stable isotope values ( δ 18O– δD) of the geothermal waters are conformable with the Mediterranean Meteoric Water Line and indicate a meteoric origin. The temperatures calculated by gas geothermometry are significantly higher than estimates from chemical geothermometers, implying that either equilibrium has not been attained for the isotope exchange reaction or that isotopic equilibration was disturbed due to gas additions en route to the surface. Evaluation of He–CO 2 abundances indicates that hydrothermal degassing and calcite precipitation (controlled probably by adiabatic cooling due to degassing) significantly fractionate the elemental ratio (CO 2/ 3He) in geothermal waters. Such processes do not affect gas phase samples to anywhere near the same extent. For the gas samples, mixing between mantle and various crustal sources appears to be the main control on the observed He–C systematics: however, crustal inputs dominate the CO 2 inventory. Considering that limestone is the main source of carbon (∼ 70 to 97% of the total carbon inventory), the carbon flux from the crust is found to be at least 20 times that from the mantle. As to the He-inventory, the mantle-derived component is found to vary up to 21% of the total He content and is probably transferred to the crust by fluids degassed from deep mantle melts generated in association with the elevated geotherm and adiabatic melting accompanying current extension. The range of 3He/enthalpy ratios (0.000032 to 0.19 × 10 − 12 cm 3 STP/J) of fluids in western Anatolia is consistent with the release of both helium and heat from contemporary additions of mantle-derived magmas to the crust. The deep faults appear to have facilitated the deep circulation of the fluids and the transport of mantle volatiles and heat to the surface.

Chloride, hydrochemical and isotope methods of groundwater recharge estimation in eastern Mediterranean areas: a case study in Jordan

AbstractJordan is classified as an arid to semi‐arid country with a population according to 1999 estimates of 4·8 millions inhabitants and a growth rate of 3·4%. 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 3·7 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 (&lt;1·3 TU). However, three samples in east Hammad, where the aquifer is unconfined, present tritium values between 1 and 4 TU. Copyright © 2007 John Wiley &amp; Sons, Ltd.

Relationship between the origin of precipitation in the Jordan Rift valley and their geochemical composition

Rainwater was sampled during seven winters at eight sites along the Jordan Rift valley in Israel. The study area is divided into two regions: the northern part located between the Sea of Galilee and the Dead Sea and the southern part between the Dead Sea and the Dead Sea–Red Sea water divide line in the Arava valley. The Dead Sea region is considered as a desert, the northern part of the study area is semidesert whereas the southern region is considered as extreme desert. Good agreement was found between the chemical and isotopic composition of rainwater its sources and air mass trajectories. In the arid areas, the contribution of salts was mainly from local sources (of up to 500 Km in diameter). Significant chemical divergence was found between rainwater deriving from marine air masses characterized by NaCl enrichment and rainwater deriving from continental air masses which are mainly characterized by Ca‐carbonate enrichment. Six main marine and continental air mass trajectories were defined, i.e., northern, northwestern, western, southwestern, eastern and local. The northern air mass trajectories contribute more salts than the southwestern air mass trajectories which exhibit the lowest rainwater salinities. The western trajectory is exclusively marine originating from the Mediterranean, while the eastern trajectory is exclusively continental and originates in the Arabian Desert. Rainwater isotopes revealed three chemically differing systems. The western marine trajectories reflect chemical setting associated with East Mediterranean Meteoric Water Line system; the continental air masses are mainly associated with the Mean Meteoric Water Line system; and whenever the eastern component is significant, a Local Meteoric Water Line prevails.

Characterization of the sources of thermal spring‐ and well water in Jordan by rare earth element and yttrium distribution and stable isotopes of H2O

AbstractFour types of thermal groundwater in Jordan were distinguished by Y and rare earth elements (REY) distribution patterns. Complementary to the stratigraphic origin of water in springs or of wells, REY patterns identify either recharge areas covered by basalt, limestones or sandstone, or interaction with basalt‐limestone contact zones. This hydrochemical grouping does not always correspond with “common geological knowledge” of the aquifer lithology of the thermal water. Therefore, comparison of the hydrochemical signatures of REY patterns and the lithological source of water yield insight into transaquifer flow. Out of 44 analysed groundwater, 18 indicated down‐ and 3 upflow of water the latter due to step faults near the Rift system. During transaquifer flow REY patterns of groundwater from basalts and gypsum beds or gypsum‐cemented sandstones are not changed by subsequent interaction with limestones, whereas in groundwater originating from dissolution of chalk and limestones REY patterns are adjusted to those typical for gypsum‐bearing sediments. Cross plots of δ18O vs. δ2H reveal essentially two trends. The main trend of water from limestone aquifers define a mixing line of past to recent meteoric water with negligible contributions of Pleistocene water. Some water from Eocene aquifers plot on the local Mediterranean meteoric water line, others plot together with water from sandstone aquifers at enhanced δ18O values due to hydrothermal overprinting.

Constraints on hydrological and paleotemperature variations in the Eastern Mediterranean region in the last 140 ka given by the δ D values of speleothem fluid inclusions

Speleothem fluid inclusions potentially provide vital data on the paleohydrological conditions in glacial and interglacial periods. We show here that δ D analyses of fluid inclusions from speleothems in three caves in the Eastern Mediterranean region (Israel) provide a basis for understanding hydrological and temperature variations in the last 140 ka. Using measured δ D fluid inclusion values and temperature ranges constrained by the present-day Mediterranean Meteoric Water Line (MMWL) and the global MWL, we show a strong compatibility between the land and marine temperature records, with the highest land temperatures occurring at 120–130 ka (17–22°C) and the present (18°C) and the lowest temperatures during the LGM, about 10°C lower than present. Interglacial waters are constrained to follow the MMWL and most glacial waters also plot close to the MMWL, with a slight shift towards the MWL. However, during two remarkable brief periods at the termination of the LGM, the waters plot on the MWL, suggesting that both sharp cooling and an increase in relative humidity above the EM Sea reduced d-excess values to those of the global system.

Hydrogeological and isotopic survey of geothermal fields in the Buyuk Menderes graben, Turkey

The main high and low enthalpy geothermal fields in the Buyuk Menderes graben (Western Anatolia) and their reservoir temperatures are as follows: Kizildere (242 °C), Germencik (232 °C), Aydin-Ilicabasi (101 °C), Yılmazkoy (142 °C), Salavatli (171 °C), Soke (26 °C), Denizli -Pamukkale (36 °C), Karahayit (59 °C), Golemezli (101 °C) and Yenice (70 °C). The geothermal systems are controlled by active graben faults. The reservoir rocks in the geothermal fields are the limestone and conglomerate units within Neogene sediments and the marble-quartzite units within Paleozoic metamorphic formations. There are clear δ 18O shifts from the Mediterranean Meteoric Water Line (MMWL) in the Kizildere, Germencik and Aydin fields, where a good relation between high temperatures and δ 18O shift has also been observed, indicating deep circulation and water rock interactions. In the Pamukkale, Karahayit, Golemezli and Yenice fields and in Soke region, low temperatures, small isotope shifts, shallow circulations and mixing with shallow cold water have been noted.