sulfur isotopes and hydrochemical variations in spring waters of southern indiana u s a abstract water chemistry and 34 s so 4 studies suggest two flow systems in the karst terrane of southern indiana 1 a shallow flow system exists which is dominated by surface water entering the ground through fractures and 2 a deeper regional groundwater flow system recharged by diffuse flow the chemistry of the water in the regional system may be dominated by the solution of gypsum in the lower st louis limestone sulfur isotope studies suggest two flow systems and show that the high so 2 4 concentrations in local waters result from solution of gypsum reported 34 s so 4 for upper mississippian evaporites and fresh water range from 14 to 19 to 8 to 12 respectively isotope analysis of gypsum cores from the lower st louis limestone evaporite unit shows 34 s values between 14 10 and 15 13 in the study area groundwater chemistry studies show a direct linear relationship between so 2 4 concentrations and 34 s values groundwater varies in so 2 4 concentrations between 20 and 1970 mg l 1 the 34 s values range from 10 61 for a conduit spring to 18 57 for a diffuse spring the waters with high so 2 4 concentrations have 34 s so 4 values higher than the local gypsum deposits analysed and contain h 2 s suggesting a deeper flow system in which fractionation by bacterial reduction of so 2 4 is occurring waters with low so 2 4 concentrations have 34 s so 4 values in the range of local fresh water indicating a shallow flow system

genesis and evolution of hco3 rich and so4 rich groundwaters of quaternary sediments pinawa canada abstract groundwaters collected from sediments at aecl research whiteshell laboratories include ca mg na hco3 na mg ca hco3 and ca mg na so4 hco3 water types the type produced is determined by the reactive phases encountered during migration through the enclosing sediments these include calcite gypsum and a clay substrate on which cation exchange occurs co2 charged soil waters undergo cation exchange reactions with solids of the enclosing sediments and dissolve calcite to saturation yielding ca mg hco3 groundwaters containing up to 700 mg l 1 total dissolved solids tds more saline sulphate rich groundwaters 1100 3000 mg l 1 tds are produced through combined reaction with gypsum calcite and a mg rich exchange substrate the type of groundwater produced is critically dependent upon the proportions of exchangeable cations on the bulk exchange substrate dissolution of gypsum increases so4 of the solutions but much of the released ca is taken onto the exchange substrate displacing na k first then mg continued gypsum dissolution causes precipitation of calcite and a decrease in solution ph the resulting saline waters are enriched in mg and na relative to ca compared with most groundwaters and are enriched in so4 relative to hco3 many sulphate rich groundwaters common to the northern north american prairies may have similar origins three solid phases exchange substrate calcite and gypsum are needed to model successfully these waters but interactions among them are complex calcite for example dissolves initially but is subsequently precipitated during evolution of sulphate rich waters consequently changes to major dissolved constituents and carbon isotopic ratios are difficult to predict without a comprehensive understanding of the geochemical evolution of these waters

the major ion composition of silurian seawater one hundred fluid inclusions in silurian marine halite were analyzed in order to determine the major ion composition of silurian seawater the samples analyzed were from three formations in the late silurian michigan basin the a 1 a 2 and b evaporites of the salina group and one formation in the early silurian canning basin australia the mallowa salt of the carribuddy group the results indicate that the major ion composition of silurian seawater was not the same as present day seawater the silurian ocean had lower concentrations of mg2 na and so42 and much higher concentrations of ca2 relative to the ocean s present day composition furthermore silurian seawater had ca2 in excess of so42 evaporation of silurian seawater of the composition determined in this study produces kcl type potash minerals that lack the mgso4 type late stage salts formed during the evaporation of present day seawater the relatively low na concentrations in silurian seawater support the hypothesis that oscillations in the major ion composition of the oceans are primarily controlled by changes in the flux of mid ocean ridge brine and riverine inputs and not global or basin scale seawater driven dolomitization the mg2 ca2 ratio of silurian seawater was 1 4 and the k ca2 ratio was 0 3 both of which differ from the present day counterparts of 5 and 1 respectively seawaters with mg2 ca2 2 e g modern seawater facilitate the precipitation of aragonite and high magnesian calcite therefore the early paleozoic calcite seas were likely due to the low mg2 ca2 ratio of seawater not the pco2 of the silurian atmosphere

stable chlorine isotopes in the palo duro basin texas evidence for preservation of permian evaporite brines experimental evaporation of seawater yields brines with 37cl from 0 0 initial to 0 9 in the palo duro basin brines with 37cl values overlapping the 0 1 to 0 4 range of halite evaporite can be generated by a set of processes including dissolution of halite in meteoric water such brines occur above and below an evaporite aquitard brines with 37cl values of 0 4 to 1 0 in the evaporite aquitard and in a deep brine aquifer cannot be generated by dissolution of halite considered with br and cl content d and noble gas content the 37cl data indicate that such brines originated as evapoconcentrated seawater high br evaporite brine formed directly from seawater on the eastern side of the basin whereas low br evaporite brines on the western side formed after an influx of meteoric water at the time of evaporite formation there has not been detectable vertical flow of meteoric water across the evaporite aquitard strata beneath the evaporite contain compartments that have been isolated geochemically since the permian

infragravity energy modulation by tides infragravity waves motions with frequencies immediately below wind generated sea and swell are believed to be radiated seaward from the surf zone where they are excited by nonlinear interactions between waves in the sea swell frequency band we describe tidal modulation of sea surface elevation variance at infragravity frequencies observed in 8 30 m water depth a few kilometers from shore at several california sites infragravity spectral levels vary by as much as a factor of 10 between high and low tide possibly because the surf zone width and beach face slope vary significantly with tidal level on the usually concave shaped beaches onshore of the observations at a fixed sensor and with approximately constant sea swell energy the observed infragravity energy is lowest at low tide

secular variation in seawater chemistry during the phanerozoic as indicated by brine inclusions in halite analysis of data on the chemical composition of primary fluid inclusions brine inclusions in primary bedded halite from many evaporite formations of northern pangea shows that during the phanerozoic the chemical composition of marine brines was oscillating significantly between the na k mg ca cl type and the na k mg cl so4 type we regard those changes as corresponding to the chemical evolution of the phanerozoic ocean the changes correlate in time with earlier suggested secular changes in the mineralogies of marine nonskeletal limestones and potash evaporites in addition to those secular changes of seawater chemistry the concentrations of k mg ca and so4 ions in marine brines underwent important changes under the influence of local factors including rock water interaction these secondary changes did not influence the principal chemical type of the brine characteristic for a given time interval in the past concentration of the ca ion did not exceed the present concentration in marine water by a

high arsenic and boron concentrations in groundwaters related to mining activity in the bigadic borate deposits western turkey this study documents the environmental impacts of borate mines in bigadic district which are the largest colemanite and ulexite deposits in the world borate bearing formations have affected the concentrations of some contaminants in groundwater groundwater quality is directly related to the borate zones in the mines as a result of water rock interaction processes calcium is the dominant cation and waters are ca so4 and hco3 type in the mine tuluborate mine from which colemanite is produced however in the simav and acep borate mines ulexite and colemanite minerals are pro duced and waters from these open pit mines are na hco3 so4 types high so4 concentrations reaching 519 mg l might be explained by the existence of anhydrite gypsum and celestite minerals in the borate zone groundwater from tuff and borate strata showed relatively low ph values 7 8 compared to surface and mine waters 8 ec values ranged from 270 to 2850 ls cm boron and as were the two important contaminants determined in the groundwaters around the bigadic borate mines arsenic is the major pollutant and it ranged from 33 to 911 lg l in the groundwater samples the concentrations of b in the study area ranged from 0 05 to 391 mg l the highest b concentrations were detected at the mine areas the extension of the borate zones in the aquifer systems is the essential factor in the enrichment of b and as and some major and trace elements in groundwaters are directly related to the leaching of the host rock which are mainly composed of tuffs and limestones according to drinking water standards all of the samples exceed the tolerance limit for as copper mn zn and li values are enriched but do not exceed the drinking water standards sulfate al and fe concentrations are above the drinking water standard for the groundwater samples 2008 elsevier ltd all rights reserved

biological and geochemical controls on diel dissolved inorganic carbon cycling in a low order agricultural stream implications for reach scales and beyond abstract movement of dissolved inorganic carbon dic through the hydrologic cycle is an important component of global carbon budgets but there is considerable uncertainty about the controls of dic transmission from landscapes to streams and through river networks to the oceans in this study diel measurements of dic 13c dic dissolved oxygen o2 18o o2 alkalinity ph and other parameters were used to assess the relative magnitudes of biological and geochemical controls on dic cycling and flux in a nutrient rich net autotrophic stream rates of photosynthesis p respiration r groundwater discharge air water exchange of co2 and carbonate precipitation dissolution were quantified through a time stepping chemical isotope 12c and 13c 16o and 18o mass balance model groundwater was the major source of dic to the stream primary production and carbonate precipitation were equally important sinks for dic removed from the water column the stream was always super saturated with respect to carbonate minerals but carbonate precipitation occurred mainly during the day when p increased ph we estimated more than half possibly 90 of the carbonate precipitated during the day was retained in the reach under steady baseflow conditions the amount of dic removed from the overlying water through carbonate precipitation was similar to the amount of dic generated from r air water exchange of co2 was always from the stream to the atmosphere but was the smallest component of the dic budget overall the in stream dic reactions reduced the amount of co2 evasion and the downstream flux of groundwater derived dic by about half relative to a hypothetical scenario with groundwater discharge only other streams with similar characteristics are widely distributed in the major river basins of north america data from usgs water quality monitoring networks from the 1960s to the 1990s indicated that 40 of 652 stream monitoring stations in the contiguous usa were at or above the equilibrium saturation state for calcite and 77 of all stations exhibited apparent increases in saturation state from the 1960 70s to the 1980 90s diel processes including partially irreversible carbonate precipitation may affect net carbon fluxes from many such watersheds

organic and inorganic carbon dynamics in a karst aquifer santa fe river sink rise system north florida usa spatiotemporal variations in dissolved organic carbon doc dissolved inorganic carbon dic major ions concentrations and other geochemical parameters including stable carbon isotopes of dic 13cdic were measured in surface water and deep and shallow well water samples of the santa fe river sink rise eogenetic karst system north florida usa three end member water sources were identified one doc rich dic poor 13cdic depleted one doc poor dic rich 13cdic enriched and one enriched in major ions given their spatiotemporal distributions they were presumed to represent soil water upper aquifer groundwater and deep aquifer water sources respectively using assumed ratios of na cl and so42 for each end member a mixing model calculated the contribution of each water source to each sample then chemical effects of biogeochemical reactions were calculated as the difference between those predicted by the mixing model and measured species concentrations in general carbonate mineral dissolution occurred throughout the sink rise system surface waters were net autotrophic and the subsurface was in metabolic balance i e no net doc or dic production or consumption however there was evidence for chemolithoautotrophy perhaps by hydrogen oxidizing microbes at some deep aquifer sites mineralization of this autochthonous natural dissolved organic matter ndom led to localized carbonate dissolution as did surface water derived ndom supplied to shallow well sites during the highest flow periods this study demonstrates linkages between hydrology abiotic and microbial processes and carbon dynamics and has important implications for groundwater quality karst morphologic evolution and hydrogeologic projects such as aquifer storage and recovery in karst systems

geochemical investigation of oils and source rocks from qianjiang depression of jianghan basin a terrigenous saline basin china abstract six oils and seven suspected source rocks from the jianghan saline basin in the central eastern part of china have been examined using a variety of geochemical techniques the results from this study show that oils from the third and fourth sections of the qianjiang formation eocene are derived from similar source materials but have a different source from the oils of xingouzui formation eocene in the same basin the oils of the xingouzui formation eocene are more mature and probably have a greater input of terrigenous source material and in all probability have migrated greater distances than the qianjiang oils oils from these sections are derived from an environment characterized as being extremely anoxic strongly reducing and highly saline the suspected source rocks examined in the study were from the qianjiang formation and were generally mature except for the shallowest sample the biomarker distributions in the suspected source rocks examined from the qianjiang formation were very different from those of the oils present in the same sections it is proposed that oils from the qianjiang formation have sources in addition to or exclusive of the suspected source rocks examined in this study

geochemistry of surface and ground water in guiyang china water rock interaction and pollution in a karst hydrological system the chemical compositions of the surface ground water of guiyang the capital city of guizhou province china are dominated by ca2 mg2 hco3 andso42 which have been derived largely from chemical weathering of carbonate rocks limestone and dolomite the production of so42 has multiple origins mainly from dissolution of sulfate evaporites oxidation of sulfide minerals and organic s in the strata and anthropogenic sources most ground water is exposed to soil co2 and therefore the h2co3 which attacks minerals contains much soil c in addition the h2so4 produced as a result of the oxidation of sulfides in s rich coal seams and or organic s is believed to be associated with the chemical weathering of rocks the major anthropogenic components in the surface and ground water include k na cl so42 andno3 with cl and no3 being the main contributors to ground water pollution in guiyang and its adjacent areas the seasonal variations in concentrations of anthropogenic components demonstrate that the karst ground water system is liable to pollution by human activities the higher content of no3 in ground water compared to surface water during the summer and winter seasons indicates that the karstic ground water system is not capable of denitrification and therefore does not easily recover once contaminated with nitrates

chemical and isotopic evidence for hydrogeochemical processes occurring in the lincolnshire limestone over 150 groundwater samples from the lincolnshire limestone have been analysed for ph major ions and 13c ratios where possible field eh and iodide concentrations were measured and methane concentrations were determined for 12 samples stable isotope ratios were determined for soil and rock carbonate samples a system of zonation allows the division of hydrogeochemical processes occurring in the aquifer the use of hydrochemical and isotope data in modelling exercises enables the re evaluation and possible enhancement of the understanding of hydrogeochemical processes the carbonate chemistry of outcrop groundwaters is explained by calcite saturation being achieved under open system conditions in the soil zone 13c ratios in the range 15 99 to 10 57 may be generated from a stoichiometric reaction with possible additional partial and or simultaneous exchange with soil co2 or carbonate the isotopic composition of soil carbonate shows the effects of precipitation from soil waters the incongruent dissolution of primary depositional limestone carbonate results in increasing magnesium and strontium concentrations and increasing 13c ratios for the groundwaters with flow down the hydraulic gradient as a result of incongruent dissolution secondary calcite may be precipitated onto fissure surfaces significant nitrate and sulphate reduction in non saline groundwaters is not supported by the results of hydrochemical and isotope modelling exercises however sulphate reduction and methane fermentation may be affecting the isotopic and chemical compositions of saline groundwaters sodium calcium ion exchange leads to limited calcite dissolution deep in the aquifer but the evolution of these groundwaters is confused by the uncertain effects of oxidation of organic carbon and mixing with a saline end member solution

meteorological and internal wave forcing of seiches along the sri lanka coast regularly observed seiches from tide gauge records around the sri lanka coast have been analysed to determine the forcing mechanisms the seiche periods range from a few tens of minutes to 2 hr fortnightly and seasonal variations of seiche amplitudes are clearly visible on the east coast these seiche amplitudes are particularly large approximately 6 8 days after spring tides with maximum seiche amplitudes observed during march april and october november suggesting that the seiche variation could be related to stratification and internal wave activity there is no visible fortnightly and seasonal variation of seiche amplitudes in west coast records instead they show a daily pattern with relatively larger seiches around 10 00 hrs local time suggesting that the seiches on the west coast could result from diurnal atmospheric forcing barotropic and 2 layer models have been developed to investigate the influence of atmospheric forcing and internal wave activity on the seiches a barotropic model applied to the west coast shows that the daily seiche amplitude variation could be simulated with cyclic diurnal meteorological forcing two layer model runs for trincomalee bay and the adjacent east coast shelf suggest that seiche amplitudes are proportional to vertical stratification and mixed layer depths therefore the observed seiches there could be excited by internal waves which originate as far away as the andaman sea during spring tides and have a travel time of 6 8 days to the sri lankan east coast however further studies including direct measurements of internal wave activity within the region are required to confirm this hypothesis

identifying the water source for subsurface flow with deuterium and oxygen 18 isotopes of soil water collected from tension lysimeters and cores the conventional identification of soil water with pre event water limits deep insights into the involvement of stationary and mobile soil water in subsurface hydrological processes in three tilled sloping field plots at a hilly area of southwestern china dominated by entisols soil water collected with a suction lysimeter was distinguished from the total soil water through an analysis of the stable isotopes deuterium and oxygen 18 differences in the depth profile of soil water before and after storm events were observed and used to examine how rainwater mixes with soil water and to identify the source contribution of different fractions of soil water in subsurface flow generation only water in the 0 10 cm soil layer was significantly affected by evaporation and infiltration water in the top 5 cm layer of the soil exhibited the lowest residence time because a storm can replace a substantial proportion of the pre event water soil water at the 10 20 cm depth showed the longest residence time as indicated by its high proportion of pre event water the isotopic signatures demonstrated that piston flow and preferential flow coexisted in this soil high antecedent soil water content and high rain intensity favor the formation of piston flow the water collected with the suction lysimeter represented the mobile fraction of the pre event water in the soil which effectively participates in the generation of subsurface flow newly infiltrated rainwater did not well mix with stationary pre event water in the soil the use of recent rainfall to represent mobile soil water may provide a practical solution for overcoming the negative effect of the spatial heterogeneity of the isotopic composition of soil water on hydrograph separation results bulk soil water and lysimeter water showed significant differences in isotopic composition under low soil water content or in the top soil layer stable isotopes in bulk and lysimeter soil water should be monitored synchronously to reveal the sources and pathways of soil water and their contributions to the generation of subsurface flow in the vadose zone c 2013 elsevier b v all rights reserved

water exchange mixing and transient storage between a saturated karstic conduit and the surrounding aquifer groundwater flow modeling and inputs from stable water isotopes water exchanges between a karstic conduit and the surrounding aquifer are driven by hydraulic head gradient at the interface between these two domains the case study presented in this paper investigates the impact of the geometry and interface conditions around a conduit on the spatial distribution of these exchanges isotopic 18o and d discharge and water head measurements were conducted at the resurgences of a karst system with a strong allogenic recharge component val d orleans france to estimate the amounts of water exchanged and the mixings between a saturated karstic conduit and the surrounding aquifer the spatio temporal variability of the observed exchanges was explored using a 2d coupled continuum conduit flow model under saturated conditions feflow the inputs from the water heads and stable water isotopes in the groundwater flow model suggest that the amounts of water flowing from the aquifer are significant if the conduit flow discharges are less than the conduit flow capacity this condition creates a spatial distribution of exchanges from upstream where the aquifer feeds the conduit recharge area to downstream where the conduit reaches its maximum discharge capacity and can feed the aquifer discharge area in the intermediate transport zone no exchange between the two domains takes place that brings a new criterion to delineate the vulnerable zones to surface water on average 4 of the water comes from the local recharge 80 is recent river water and 16 is old river water during the november 2008 flood both isotopic signatures and model suggest that exchanges fluctuate around this steady state limited when the river water level increases and intensified when the river water level decreases the existence of old water from the river suggests a transient storage at the aquifer conduit interface that can be considered as an underground hyporheic zone

characterizing the heterogeneity of karst critical zone and its hydrological function an integrated approach spatial heterogeneity in the subsurface of karst environments is high as evidenced by the multi phase porosity of carbonate rocks and complex landform features that result in marked variability of hydrological processes in space and time this includes complex exchange of various flows e g fast conduit flows and slow fracture flows in different locations here we integrate various state of the art methods to understand the structure and function of this poorly constrained critical zone environment geophysical hydrometric and tracer tools are used to characterize the hydrological functions of the cockpit karst critical zone in the small catchment of chenqi guizhou province china geophysical surveys using electrical resistivity tomography ert inferred the spatial heterogeneity of permeability in the epikarst and underlying aquifer water tables in depression wells in valley bottom areas as well as discharge from springs on steeper hillslopes and at the catchment outlet showed different hydrodynamic responses to storm event rainwater recharge and hillslope flows tracer studies using water temperatures and stable water isotopes d and 18o could be used alongside insights into aquifer permeability from ert surveys to explain site and depth dependent variability in the groundwater response in terms of the degree to which new water from storm rainfall recharges and mixes with old pre event water in karst aquifers this integrated approach reveals spatial structure in the karst critical zone and provides a conceptual framework of hydrological functions across spatial and temporal scales

the role of the subcutaneous zone in karst hydrology abstract the subcutaneous zone is the upper weathered layer of rock beneath the soil but above the permanently saturated phreatic zone it is of particular hydrological importance in karst because of its high secondary permeability arising from the considerable chemical solution in this zone however corrosional enlargement of fissures diminishes with depth thus permeability decreases in the same direction with the result that percolation is inhibited except down widened master joints and faults storage of water consequently occurs in this zone particularly after storms the upper surface of this suspended saturated layer in the subcutaneous zone is defined by a perched water table which slopes towards points of rapid vertical percolation the potential induces lateral water movement converging on the most permeable areas such as beneath dolines leakage from the subcutaneous store sustains slow percolation in the vadose zone cross correlation of rainfall with percolation rates in caves in new mexico u s a and new zealand reveal response lags of 2 14 weeks with no apparent relationship to depth below the surface other percolation sites show no correlation with rainfall interpreted as being a consequence of considerable friction in tight fissure networks the recognition of storage and rapid as well as very slow percolation from the subcutaneous zone requires re interpretation of the components of hydrographs from karst springs and of some conceptual models of karst aquifers the importance of subcutaneous storage in sustaining baseflow discharge at some sites must be recognised as must the contribution of subcutaneous water to flood hydrographs methods of estimating the volumes of subcutaneous and phreatic components of karst spring flood hydrographs are presented the paper concludes with a discussion of the significance of subcutaneous hydrologic processes for an understanding of karst geomorphology the desirability of explaining karst landform evolution in terms of hydrologic processes is stressed

conceptual hydrogeological model of flow and transport of dissolved organic carbon in a small jura karst system summary this paper aims at characterizing infiltration and solute transport processes in a karst system during flood events in order to build a conceptual model of hydrogeological functioning the study site is the small karst system of fertans in the french jura soil cover rock matrix and a small spring were monitored to measure hydrological and hydrochemical parameters and particularly a continuous dissolved organic carbon doc signal which is a relevant environmental tracer of fast infiltration we used two combined approaches first from hydrodynamic and hydrochemical data we identified the system structure consistent with a dual porosity scheme and characterized the main processes occurring during flood events second on the basis of this scheme we built a new conceptual hydrogeological model coupled with doc transport to numerically validate the hydrological functioning this modelling approach is based on a rainfall discharge model to simulate spring flow solute transport is modelled using mixing equations including an empirical retardation factor as well as a first order solute decay the model was calibrated and validated on a set of nineteen flood events showing its performances in simulating spring hydrographs and delayed doc signals during flood events with various rainfall intensities we showed that the recharge area of the karst system varied largely with low and high groundwater periods which was attributed to the state of hydraulic connectivity in the unsaturated zone the soil cover appeared to play an important role of mixing and transfer for the recharge water the model simulated the contributions of pre event and event waters during flood events and allowed a better quantification of the available resource it showed in particular that total discharge of some flood events during low water periods is mainly composed of pre event water via piston flow type processes finally this study shows that the mixing model can simulate solute transport correctly taking into account degradation and retardation processes it highlights the need for a quantitative approach on hydrochemical studies of karst systems in order to understand them better

parsimonious recharge discharge modeling in carbonate fractured aquifers the groundwater flow in the gran sasso aquifer central italy summary in the carbonate fractured aquifer of the gran sasso central italy numerical simulations have been applied to validate a conceptual model of the recharge discharge cycle at regional scale to identify the effective aquifer features that mostly affect the spring discharges simple parsimonious models based on few key parameters whose effective values are well constrained by previous hydrological geological studies are used input data are represented by infiltration calculated considering rainfall snowmelt and runoff in endorheic basins and effective permeability distribution estimated by geological tectonic and hydrogeological settings of the aquifer discharges of tapped springs and tunnel drainages for the 1999 2009 period have been simulated after estimating the recharge area of each monitored spring by the hydrogeological setting and checking them by mean isotope elevation values discharge monitoring has been compared with the simulations obtaining a good agreement both at seasonal and yearly time basis the simulations will also be useful for previewing discharge in drought period and evaluating protection zones of tapped springs in the territory of a national park

chlorine isotopic geochemistry of salt lakes in the qaidam basin china abstract the isotopic compositions of chlorine in salt lake brine coexisting with halite oil field water and river water from the qaidam basin qinghai china have been examined using high precision measurement of chlorine isotopes based on thermal ionization mass spectrometry of the cs 2 cl ion 37 cl values vary from 2 05 to 2 94 with average values of 2 94 for hot spring water 1 35 for river water 0 38 for oil field brine 0 40 for saline water and 0 63 for salt lake brine the preliminary results show isotopic fractionation of chlorine in salt lake brine during salt precipitation the variation of the 37 cl value in these salt lakes is mainly associated with brine evaporation and halite precipitation and with the hydrochemistry of the input water the chlorine isotopic composition may reflect the degree of evaporation of the salt lake brine and may be used to distinguish brines that are in equilibrium with precipitating salts and brines that have dissolved earlier evaporates

selective recharge and isotopic composition of shallow groundwater within temperate epigenic carbonate aquifers summary this paper considers the variation of 18o and 2h vsmow in precipitation and shallow groundwater from carbonate aquifers that lend insight into the source and timing of recharge within temperate epigenic karst the shallow groundwater collected during 2010 and 2011 at stream cave sc and natural bridge caverns nbc represent one input to and the primary output from the redmond creek karst aquifer in the cumberland plateau of southeast kentucky respectively these data are compared with the isotopic composition of concurrent samples of precipitation from the same watershed that covers some 1900 ha values of 18o and 2h at sc and nbc are statistically similar and cluster at the midpoint of the local meteoric water line these values remain surprisingly constant despite seasonal changes in temperature regimens and discharge samples in 2012 from regional springs that include redmond creek are more depleted in the heavier isotope and similarly stable despite coming from aquifers of a range of sizes and physical characteristics applying a priestly taylor model for daily values of potential evapotranspiration only 43 of the 1 10 m of precipitation in the 2010 2011 dataset remains as potential recharge primarily during cooler months with lower solar insolation weighting 18o and 2h values of precipitation by potential recharge creates a better match with the isotopic composition of shallow groundwater than by weighting by precipitation amount the isotopic composition and deuterium excess of precipitation samples are directly and inversely proportional to temperature respectively deuterium excess in this study and displays intra and inter annual variation that ranges from a minimum of 11 1 to a maximum of 29 5 that demonstrate the higher than average deuterium excess in greater appalachia and the shifting latitude of moisture sources including a significant winter component of re evaporated continental moisture

boron concentration and isotopic composition of halite from experiments and salt lakes in the qaidam basin abstract the concentration and isotopic abundance of boron in salt can be used to trace paleosalinities and depositional environments for marine and non marine evaporites however the mechanism of incorporating boron into halite during evaporation of salt lake brines is subject to dispute and there have been few studies of boron concentrations and isotopic compositions during this process due to the low boron concentration in halite a group of evaporation experiments from artificial solutions and salt lake brines have been analyzed in this study the results of boron concentration and isotopic analyses demonstrate that the boron in halite comes mainly from fluid inclusions with a lesser amount from coprecipitation the isotopic fractionation factors between the brine and halite are from 0 9857 to 1 0000 for the evaporation experiments and 0 9945 to 1 0009 for natural samples from the salt lake the 11b values of halite from the qaidam basin salt lakes vary from 4 7 to 25 8 compared to 4 7 to 31 4 in the salt lake brines these values are controlled by the boron isotopic composition of the boron sources ph values and na ca ratios in the salt lake brines the variation of boron isotopes in halite may be used to trace the hydrochemical evolution and paleoevaporation environment in salt lakes

the coupling between harbor seiches at palawan island and sulu sea internal solitons abstract between 1989 and 1991 the authors made observations that confirm and elucidate the coupling between harbor seiches at puerto princesa on palawan island in the philippines and tide generated internal solitons in the sulu sea published tidal current predictions for basilan strait in the sulu archipeligo were used to produce an index to the daily ebb tidal flows near pearl bank where the solitons originate the coherence between predicted maximum ebb tidal current speed and observed seiche activity was 0 60 and the phase lag between the two quantities closely matched published estimates of the time required for solitons to cross the sulu sea arrival of the sulu sea waves immediately offshore of puerto princesa in the form of internal bores corresponded in time to the initiation of harbor seiche activity a more precise estimate of soliton travel time was determined from the time difference between predicted maximum ebb current and the initiation of seiche activity and it was found to have a remar

peculiarities of salt lake sediments as potential source rocks in china abstract hypersaline lake sediments are widely distributed in china and can be good sources for petroleum the palaeogene sediments of the jianghan basin in eastern china are a typical example composed of salt lake evaporite clastic facies in fault subsided basins their organic matter is variable but is dominated by type ii kerogen the biological marker characteristics of core extracts and oils from the jianghan basin include i low oep values for n alkanes and occasionally an even odd predominance ii a high concentration of phytane iii a relatively high gammacerane 17 h 21 h hopane ratio and iv abundant mainly nickel porphyrins sample guang 33 k 33 is typical of the immature oils found in the jianghan basin geological and geochemical data both indicate that it was generated from source rocks in the maturity range r 0 0 45 0 55 its characteristics are similar to those of immature source rocks with high concentrations of phytane steranes triterpanes and nickel porphyrins and for an oil extremely low values for molecular parameters of maturity such as c 29 20s 20s 20r 14 h 17 h steranes c 32 22s 22s 22r 17 h 21 h hopanes and dpep dpep etio porphyrins

modeling of groundwater processes in a karstic aquifer of sierra madre oriental mexico abstract the sierra madre oriental smo is composed of ranges with important regional geological structures in highly fractured carbonate rocks abra formation which facilitate the recharge of aquifers at the regional scale recharge occurs in the western smo and locally in ranges such as palmillas la colmena and abra while the regional discharge is to the east in the huasteca zone intermountain valleys such as el salto are located near the regional discharge zone three end members were identified in these regions one related to local flow another to intermediate and a third to regional flow these flows define ternary mixing processes in groundwater in this paper the evolution of groundwater is studied which is important for learning the system performance and hydrogeochemical processes through vishmod virtual samples in hydrochemical modeling methodology the mixing model for the intermountain valleys indicates that many recharges occur for which local flow contributes 68 3 intermediate flow 12 3 and regional flow 19 4 the inverse modeling shows that the water rock interaction precipitation and or dissolution of calcite gypsum and dolomite are the main processes occurring in the aquifer system of the intermountain valleys

identifying water sources in a karst aquifer using thermal signatures using thermal data a unique approach to delineate flow components in a karsts aquifer was conducted thermal signatures from seven wells and six springs were analyzed to determine potential relationships among different storage reservoirs and the air temperature the temperature signatures revealed three distinct reservoirs epikarst shallow groundwater and deep groundwater the reservoirs have different thermal signatures and relationships with the air temperature during a wetter period the epikarst water temperatures more closely follow the air temperature trend and are closer in value but during drier conditions the shallow groundwater temperatures are more similar in value to air temperature deep groundwater temperatures show no relationship to variations in surface air temperature using the water temperatures from the three reservoirs the sources of water at two major springs copperhead and langle were delineated during the wetter period the shallow groundwater and the epikarst were the primary contributors of water to the springs as conditions became drier a transition occurred the deep groundwater became the major source of water to the springs variation in temperatures of waters at copperhead and langle spring is a result of the epikarst and the shallow groundwater which represents ineffective thermal reservoirs

seiches in the eastern caribbean data from a network of tide gauges in the eastern caribbean have been used to investigate the periods and amplitudes of seiches at each station and the coherence in seiche activity between stations seiches in this area have very small amplitudes but they can be readily identified in the sea level spectra obtained from high quality high frequency tide gauges most of their periods are found to be determined by the quarter wavelength response of the adjacent shelf and their q values are generally consistent with them being relatively undamped at several stations the forcing responsible for the seiches is clear at others the forcing is harder to pin down seiches appearing seemingly randomly and resulting in what has been called continuous seiche overall it is demonstrated that seiches or at least their statistics need to be better understood and to be included effectively in studies of extreme sea levels also related to shelf resonance two possible examples of tidal ringing have been identified

contributions of c3 c4 organic materials and carbonate rock to dissolved inorganic carbon in a karst groundwater system on miyakojima island southwestern japan summary groundwater 13 c values and chemical compositions were employed to quantitatively evaluate the controlling processes and sources of dissolved inorganic carbon in a karst aquifer system on miyakojima island mi southwestern japan most mi groundwater is ca hco 3 type water but some na cl ca cl or na hco 3 type groundwaters occur formed mainly by seawater intrusion and partly by cation exchange reactions calculations using the wateq4f and phreeqc programs revealed that all mi groundwater not just the ca hco 3 type was strongly influenced by calcite dissolution in a karst aquifer system open with respect to soil co 2 initially derived from organic materials with mainly around 10 50 matm as pco 2 and that most groundwater was saturated with respect to calcite moreover oxidation of ammonium sulfate applied as fertilizer added h to the mi groundwater resulting in surplus calcite dissolution these processes sufficiently explained contents of alkalinity dic and ca 2 in the groundwater and were evaluated by model calculation using the phreeqc program with measured groundwater 13 c and ph values the results showed that the average mass fractions of dissolved inorganic carbon dic initially from calcite dissolution and c3 and c4 organic materials in the groundwater were 46 4 18 5 and 35 1 respectively the model results regarding the origins of dic in the groundwater agreed fairly well with land use distributions on mi in particular with the spatial distribution of forest and sugarcane fields and gave us some constrains of groundwater recharge areas and flowpaths

seasonal fluctuation in δ15n of groundwater nitrate in a mantled karst aquifer due to macropore transport of fertilizer derived nitrate twenty wells were sampled and analyzed for nitrate content and nitrogen isotopes during late september 1986 the groundwater nitrate 15n values ranged from 6 8 to 17 6 with a mean of 10 3 eleven samples had 15n values greater than 9 5 indicating an animal waste origin septic tanks are probably the predominant source of waste derived nitrate macropores draining septic tank filter fields may provide a nearly continuous flow of effluent to the aquifer the 15n values of the other nine samples ranged from 6 8 to 8 4 suggesting a possible mixing of waste derived nitrate and that derived from isotopically lighter cultivation sources i e inorganic fertilizer and or mineralized soil organic nitrogen the twenty wells were resampled during late may 1987 shortly after inorganic fertilizers had been applied to the corpland throughout the study area the groundwater nitrate 15n values ranged from 3 6 to 14 7 with a mean of 8 3 nineteen of the wells showed a shift towards the lighter 15n values expected from the fertilizer derived nitrate the 15n decreases ranged from 0 6 to 4 8 with a mean of 2 2 despite the apparent influx of fertilizer derived nitrate eleven samples with 15n 8 0 to 14 7 still were composed of predominantly waste derived nitrate only nine samples with 15n 3 0 to 5 8 may have had fertilizer derived component approaching in magnitude that of waste derived nitrate regional groundwater nitrate concentration did not substantially increase macropore cracks root channels etc flow appears to contribute significantly to the recharge of the aquifer rapid response of the groundwater nitrate 15n values to fertilization demonstrates the ability of macropore flow to transport fertilizer derived nitrate which has been flushed from the tilled soil layer other agriculture chemicals pesticides and herbicides may also be transported to the aquifer in this manner

geochemical and statistical evidence of recharge mixing and controls on spring discharge in an eogenetic karst aquifer summary information about sources of recharge distributions of flow paths and the extent of water rock reactions in karst aquifers commonly result from monitoring spring chemistry and discharge to investigate the relationship between spring characteristics and the complexities of karst aquifers we couple variations in surface and groundwater chemistry to physical conditions including river stage precipitation and evapotranspiration et within a sink rise system through a 6 km portion of the upper floridan aquifer ufa in north central florida principal component analysis pca of time series major element compositions suggests that at least three sources of water affect spring discharge including allogenic recharge into a swallet diffuse recharge through a thin vadose zone and water upwelling from deep within the aquifer the deep water source exerts the strongest influence on water chemistry by providing a majority of na mg2 k cl and so 4 2 to the system anomalously high temperature at one of several monitoring wells reflects vertical flow of about 1 m year mass balance calculations suggest diffuse recharge and deep water upwelling can provide up to 50 of the spring discharge however their contributions depend on head gradients between the conduit and surrounding aquifer matrix which are influenced by variations in precipitation et and river stage our results indicate that upwelling from deep flow paths may provide significant contributions of water to spring discharge and that monitoring only springs limits interpretations of karst systems by masking critical components of the aquifer such as water sources and flow paths these results also suggest the matrix in eogenetic aquifers is a major pathway for flow even in a system dominated by conduits

ediacaran seawater temperature evidence from inclusions of sinian halite abstract seawater temperatures throughout earth s history have been suggested to illustrate a long term cooling trend from nearly 70 c at 3500 ma to around 20 c at 800 ma the terminal neoproterozoic prior to the cambrian explosion is a key interval in evolutionary history as complex multicellularity appeared with the advent of the ediacara fauna these organisms were likely the first that required higher levels of atmospheric and dissolved marine oxygen for their sustainability it is known that most modern macroinvertebrates are intolerant of temperatures in excess of 45 c perhaps more importantly these high seawater temperatures limit the potential of dissolved oxygen and therefore become an integral part of this evolutionary story previously our understanding of seawater temperature during the terminal neoproterozoic comes only from 18 o 16 o and 30 si 28 si ratios ascertained from a limited number of cherts isotopic ratio methods for assessing seawater temperatures are inherently indirect and have a wide range of oscillation however maximum homogenization temperatures th max of primary fluid inclusions in halite provide a direct means of assessing brine temperature and have been shown to correlate well with average maximum air temperatures the oldest halites date to the neoproterozoic lower paleozoic 700 500 ma and ediacaran representatives can be found in sichuan province china which do preserve primary fluid inclusions for analysis via cooling nucleation methods we utilized halite samples from the changning 2 well correlative to the dengying formation 551 542 ma to provide a direct assessment of terminal neoproterozoic seawater temperature our measurements indicate that seawater temperatures where these halites formed are highly similar to tropical phanerozoic seawater temperature estimates from compiled paleotemperature data the decline in seawater temperatures over the course of the proterozoic accompanied by the reduction of seawater salinity with the sequestration of salt in massive halite deposits in the neoproterozoic allowed the ocean system to accumulate more dissolved oxygen and potentially paved the way for the evolutionary innovation of complex multicellularity

the nitrogen isotope composition of groundwater nitrates from the east midlands triassic sandstone aquifer england abstract the 15 n 14 n composition of nitrates dissolved in groundwaters from 23 abstraction sites in the east midlands sherwood sandstone are reported dissolved n 2 ar ratios are with two exceptions consistent with atmospheric input and show that denitrification does not occur throughout most of the aquifer the nitrogen isotope composition of nitrates dissolved in the groundwaters can be shown not to have been mixed or fractionated to any significant extent within the aquifer the observed 15n no3 isotopic variations are attributed to four nitrate sources all of which are associated with agricultural land use

metal mobility due to storm events on an impacted hillslope in palmerton pa abstract water samples were collected continuously from perennial springs on a hillslope impacted by historical metal deposition to study the hydrologic and geochemical behavior of a watershed during storm events and assess the natural attenuation of metals in soil water samples were collected throughout storm hydrographs for inorganic chemistry analyses and a sequential extraction was performed on watershed soil samples despite 30 a of natural attenuation at the site zn is mobilized into streamwater during storm events with concentrations ranging from 18 to 452 g l while cd and pb concentrations in water samples remained relatively constant zn concentration increased corresponding with the peak in the hydrograph indicating this metal is being released from adsorption sites located in an unsaturated zone that is temporarily inundated during storm events zinc is held on exchangeable water and acid soluble sites and in the reducible fraction further indicating zn may be released as a result of the downward movement of water through the soil profile equilibrium geochemical modeling predicts zn desorption with a decrease in ph which may occur as a result of site re vegetation the long legacy of metal emissions from a historical smelting operation will continue to limit the attenuating ability of this site

carbon isotope fractionation between dissolved carbonate co32 and co2 g at 25 and 40 c abstract carbon isotope fractionations e hco 3 co 2 g and e co 3 co 2 g have been obtained in open system experiments at medium ph measured isotopic fractionations e between total dissolved carbonate tdc and co 2 g were 7 32 0 07 and 6 15 0 08 at 25 and 40 c respectively assuming e co 2 aq co 2 g 1 06 from vogel et al 19 5 and ion speciation in the solution calculated fractionations e hco 3 co 2 g are 8 21 at 25 c and 6 71 at 40 c at high ph measured isotopic fractionations between tdc and co 2 g were 8 30 0 09 and 6 69 0 15 at 25 and 40 c respectively considering ion speciations and the above fractionation e hco 3 co 2 g we derived e co 3 co 2 g as equal to 8 38 at 25 c and 6 67 at 40 c

the mad sea phenomenon in the strait of sicily sea level observations at cape bon tunisia and mazara del vallo sicily show that large coherent oscillations exist across the strait of sicily with significant energy bands centered at periods of 35 3 41 6 50 6 75 8 and 134 5 min whose possible structure is confirmed by a numerical approximation to the gravitational barotropic normal modes with realistic topography it is observed that these oscillations are related to the passage of synoptic weather systems over the region an investigation on the configuration phase velocity and direction of approach of atmospheric disturbances over the region suggests that the oscillations in the strait of sicily could be forced by instabilities that develop in large scale low pressure fronts that propagate as pressure gravity waves with an approximate phase speed between 24 and 30 m s21

high resolution stratigraphy with strontium isotopes the isotopic ratio of strontium 87 to strontium 86 shows no detectable variation in present day ocean water but changes slowly over millions of years the strontium contained in carbonate shells of marine organisms records the ratio of strontium 87 to strontium 86 of the oceans at the time that the shells form sedimentary rocks composed of accumulated fossil carbonate shells can be dated and correlated with the use of high precision measurements of the ratio of strontium 87 to strontium 86 with a resolution that is similar to that of other techniques used in age correlation this method may prove valuable for many geological paleontological paleooceanographic and geochemical problems

choosing the best ancient analogue for projected future temperatures a case using data from fluid inclusions of middle late eocene halites abstract after the paleocene eocene thermal maximum petm global temperature and co2 levels decreased concurrently in the middle late eocene using different approaches estimated co2 levels of the middle late eocene are very similar to the 1000 ppm co2 level projected for the next 100 years as a result of increasing greenhouse gas concentrations the average global temperature is projected to increase from 1 4 to 5 8 c by 2100 relative to 2001 levels thus the middle late eocene may be the best ancient analogue for a future with increased temperatures due to burning of fossil fuels in order to explore the sensitivity range of global annual temperature with respect to co2 concentration exact atmospheric co2 concentrations and air temperatures of ancient analogs must be known previous palynological studies provide only indirect estimates of temperature however the homogenization temperature of fluid inclusions in halites obtained by the cooling nucleation method can provide the exact temperature of saline lake water which is similar to overlying air temperature in shallow lakes in this paper we measured the range of homogenization temperatures from 5 8 to 43 3 c of fluid inclusions in middle late eocene halites of the yunying depression central china the maximum homogenization temperature of fluid inclusions thmax in these middle late eocene halites is 4 6 c higher than the modern extreme highest temperature 38 7 c recorded for this area

snowmelt infiltration and storage within a karstic environment vers chez le brandt switzerland summary even though karstic aquifers are important freshwater resources and frequently occur in mountainous areas recharge processes related to snowmelt have received little attention thus far given the context of climate change where alterations to seasonal snow patterns are anticipated and the often strong coupling between recharge and discharge in karst aquifers this research area is of great importance therefore we investigated how snowmelt water transits through the vadose and phreatic zone of a karst aquifer this was accomplished by evaluating the relationships between meteorological data soil water content vadose zone flow in a cave 53 m below ground and aquifer discharge time series data indicate that the quantity and duration of meltwater input at the soil surface influences flow and storage within the soil and epikarst prolonged periods of snowmelt promote perched storage in surficial soils and encourage surficial lateral flow to preferential flow paths thus in karstic watersheds overlain by crystalline loess a typical pedologic and lithologic pairing in central europe and parts of north america soils can serve as the dominant mechanism impeding infiltration and promoting shallow lateral flow further hydrograph analysis of vadose zone flow and aquifer discharge suggests that storage associated with shallow soils is the dominant source of discharge at time scales of up to several weeks after melt events while phreatic storage becomes import during prolonged periods without input soils can moderate karst aquifer dynamics and play a more governing role on karst aquifer storage and discharge than previously credited overall this signifies that a fundamental understanding of soil structure and distribution is critical when assessing recharge to karstic aquifers particularly in cold regions

solute and isotopic geochemistry and ground water flow in the central wasatch range utah ground water flow systems in the rugged central wasatch range utah were investigated by solute and isotopic methods six types of ground water systems were identified on the basis of rock type and structure the systems are broadly grouped into four categories 1 granitic systems 2 non granitic systems a unconsolidated alluvial systems b consolidated sedimentary rock systems and c fault controlled systems 3 thermal systems 4 mine drainage systems these ground water systems have distinctive solute and isotopic chemistries based on an analysis of 3h and 14c data all of the ground waters have a component of post 1952 recharge water and most of the ground waters are composed almost entirely of post 1952 recharge water a few of the ground water systems contain some water which is hundreds to perhaps thousands of years old the 18o and 2h data plot on a local meteoric water line and none of the data exhibit a positive 18o shift the absence of a positive 18o shift suggests maximum aquifer temperatures are approximately 100 c granitic terrains are dominated by fracture controlled local ground water flow systems which respond rapidly to recharge events the granitic ground water systems have estimated maximum circulation depths of about 160 m below land surface all the alluvial most of the consolidated sedimentary bedrock and some of the fault controlled ground water systems are shallow circulating local flow systems with short travel times ground water circulation of most of the local flow systems is within 200 m of land surface and is bedding plane controlled some of the consolidated bedrock and many of the fault controlled ground water systems are of the intermediate type and have circulation depths to 500 m four thermal ground water systems have been identified the thermal systems are heated by the geothermal gradient and have not circulated deeper than 2 2 5 km the thermal systems are of the intermediate and regional type the solute chemistry of most of the non granitic ground waters may be attributed to the dissolution of carbonate minerals and minor amounts of gypsum contributions of external co2 g to some of the thermal systems from either metamorphic or silicate hydrolysis processes is suspected

using isotope fractionation of nitrate nitrogen and nitrate oxygen for evaluation of microbial denitrification in a sandy aquifer the nitrate input into the groundwater from forest and agricultural land in the fuhrberger feld catchment area is virtually completely degraded by microbial denitrification in the aquifer five multilevel groundwater sampling wells show characteristic depth functions of nitrate proving the denitrification process a series of 10 samples of arable land groundwater was taken from different depths at these multilevel wells and isotope ratios of 15n14n and 18o16o in the nitrate were measured the sampling was based on the two dimensional vertical plane groundwater flownet and on the knowledge of the landuse upgradient of the multilevel wells high nitrate concentrations are associated with low 15n and low 18o values and vice versa the 15n 18o ratio indicates a linear increase with a slope of 1 2 1 the microbial dentrification accords with a rayleigh process with calculated enrichment factors of e 15 9 for 15n and e 8 0 for 18o three samples taken from groundwater recharged under coniferous forest show deviating characteristics low nitrate concentrations with low 15n values 1 4 but very high 18o values 40 50 using the previously quantified enrichment factors for 15n and 18o an attempt was made to ascertain the significance of denitrification in specific depth sections at two other multilevel wells 7 samples in two cases quantitative assessments on the degree of nitrate concentration decrease owing to denitrification were possible however in other cases the specific nitrate isotope fractionation was masked by the variability of nitrate concentration and of nitrate isotope ratios in the corresponding groundwater recharge preventing definite interpretations

stable isotope geochemistry of sulfate in relation to hydrogeology in southern saskatchewan canada abstract isotope and chemical analyses were carried out on soil and water samples collected from testholes drilled into different stratigraphic layers at six locations in the assiniboia area southern saskatchewan to understand the origin and distribution of so 4 and sources of groundwater recharge the 34 s so 4 and 18 o so 4 values were mostly negative indicating oxidation of highly reduced sulfide in subsurface environments as the major source of so 4 in the soils and groundwaters however positive or near positive 34 s and 18 o values in some of the samples indicated that oxidation of sulfide with positive or near positive 34 s values or dissolution of a so 4 mineral such as evaporite gypsum may serve as alternate sources of s salt concentration and isotope compositions in the eastend sand were nearly uniform in comparison with till and shale layers total s content in the sediments varied from 0 7 to 3 2 g kg with greater accumulations in the till layer which were mostly 1 0 g kg the insoluble s fraction of the sediments was 4 s was the major form of s the 34 s and 18 o values of soluble so 4 and 18 o and d values of groundwaters provide supporting evidence of groundwater flow direction determined by other techniques the d and 18 o values of the groundwater samples varied between 131 and 119 and 15 2 to 11 4 respectively without any correlation with stratigraphy these data plot on a d vs 18 o line with a slope of 2 0 this departure from the meteoric water line with slope of 8 0 appears to be the result of evaporation or oxygen exchange with soil minerals the o isotope data suggest that exchange between so 4 and h 2 o is very slow under the conditions prevailing in the subsurface

sulfate in brines in the crystalline rocks of the canadian shield abstract deep groundwaters in crystalline rocks typically are very saline and are characterized by a rather unique ca na cl dominated chemistry sulfate is present in variable amounts and may be linked to both the geochemical evolution of these fluids as well as to recent processes initiated through mining activities it is possible to distinguish on the basis of isotopic compositions between brine sulfate and secondary sulfate formed by oxidation of sulfides the latter is characterized by 34 s values which reflect the local mineral sulfide precursor and 18 o close to or below 0 smow the isotopic composition of the brine sulfate is characterized by 18 o and 34 s values which resemble marine isotopic compositions at some localities at others they could be explained as being of magmatic hydrothermal origin it is likely that the sulfate participated in the geochemical evolution of these brines thus its isotopic composition reflects geochemical processes rather than a primary origin no evidence for the influence of bacterial reduction was found

a model for the generation of coastal seiches by deep sea internal waves abstract a dynamical mechanism for the generation of coastal sciches by deep sea internal waves is investigated using a linear two layer coastal model in which internal waves from the deep ocean impinge upon a step shelf bottom topography for periodic incident waves a pronounced peak in the shelf response occurs at each coastal seiche frequency the maximum amplitude over the shelf is almost directly proportional to the degree of stratification suggesting that sciche activity should vary with seasonal changes in the stratification based on the periodic solutions fourier transforms are used to determine the response to one or more internal wave pulses and the results are qualitatively consistent with observations for geometry and gratification which are representative of the caribbean coast of puerto rico reasonably realistic incident pulses preferentially excite the basic seiche frequency and a rather small amplitude pulse 10 m can easily generate currents at the shelf break of 8 10 cm s 1 fu

hydrogeological and mixing process of waters in aquifers in arid regions a case study in san luis potosi valley mexico the climatic conditions of arid regions are characterized by high temperatures low precipitation and high evapotranspiration rates that can explain the reduced recharge of aquifers thus in these regions there are some problems related to the groundwater quality and recharge that makes worse the problem of groundwater supply a model taking into account ternary mixtures is presented and applied to a case study the aquifer of san luis potosi valley located in the highlands of the central part of mexico in this valley four hydrochemical facies were identified that correspond to the ca na k hco3 na k ca hco3 ca hco3 and ca so4 types from this characterization it was found out that the recharge area known as bledos graben is located at the se of the valley the deep water flow comes from there villa de reyes and alvarez range to the center of the valley mixture fractions were obtained by using chlorides and fluorides as conservative elements from which it was possible to quantify the contribution of each member to the groundwater quality according to these results the contributions to the water extracted from this aquifer are as follows shallow flows 50 deep flows from villa de reyes 27 and flows coming from the alvarez ranges about 15

pressure forced seiches of large amplitude in inlets of the balearic islands 2 observational study in part 1 of this study gomis et al 1993 proposed a possible mechanism for the generation of large amplitude seiches observed in inlets of the balearic islands in part 2 we revise the proposed mechanism in light of recent observations these consist of simultaneous records of sea level bottom pressure measured at three locations inside and outside ciutadella inlet and atmospheric pressure measured at four sites inland nearby first results that support the existence of offshore surface waves of atmospheric origin are shown next a detailed analysis of atmospheric data reveals the passage of non dispersive waves with a predominant direction and phase speed that seem to be about the same during seiche events finally coherence phase difference and admittance functions estimated for different pairs of instruments are compared with the theoretical results all observations indicate that large amplitude seiches observed in ciutadella are likely the result of a resonant coupling between offshore surface waves generated by atmospheric disturbances and the fundamental mode of that inlet as suggested in part 1 however the analytical model used in part 1 is clearly too simple to explain the observed characteristics of the offshore surface waves

the major composition of a middle late eocene salt lake in the yunying depression of jianghan basin of middle china based on analyses of fluid inclusions in halite abstract during the cretaceous tertiary transition in eastern china abundant halites formed in non marine areas many continental salt deposits from inland salt lakes were formed in eastern china in faulted basins as a result of the northward movement and collision of the indo china plate with the eurasian plate including the bohai gulf basin however a marine transgression versus a non marine origin of these evaporites remains to be determined primary fluid inclusions trapped in halite deposits can directly record the composition of evaporated seawater or salt lake water such as those in the cretaceous halite in the khorat plateau laos and thailand area can resolve the origins of the evaporate deposits recent fluid inclusions data in the khorat plateau coincide with the predicted secular variation of seawater and are comparable to other fluid inclusions in cretaceous marine halite indicating these fluid inclusions are directly related to a marine transgression our analyses in this study shows that the average k mg2 and so 4 2 contents are 8 8 5 0 and 6 8 g l respectively in the primary fluid inclusions in halite of middle late eocene from the yunying depression of china these numbers are much less than those in the contemporary spanish primary fluid inclusions in halite precipitated from seawater 16 4 36 3 and 12 5 g l for k mg2 and so 4 2 respectively furthermore br contents of all fluid inclusion samples in halite from the yunying depression are lower than 2 ppm vs 55 58 ppm at the base of spanish contemporary marine halite and their 37cl values range from 0 11 to 2 94 vs 0 09 to 0 24 in sylvite of spanish deposit indicating that the compositions of the middle late eocene brines trapped in halite in the yunying depression of china are very different from those derived from the contemporary seawater and are considered to be resulted from evaporation of an inland saline lake water with little influence of seawater

sedimentary sulfur geochemistry of the paleogene green river formation western usa implications for interpreting depositional and diagenetic processes in saline alkaline lakes abstract the sulfur geochemistry of the lacustrine paleogene green river formation colorado utah and wyoming usa is unlike that of most marine and other lacustrine rocks distinctive chemical isotopic and mineralogical characteristics of the formation are pyrrhotite and marcasite high contents of iron mineral sulfides strikingly enriched in 34 s cyclical trends in sulfur abundance and 34 s values and long term evolutionary trends in 34 s values analyses that identified and quantified these characteristics include carbonate free abundance of organic carbon 0 13 47 wt total iron 0 31 13 wt reactive iron 70 of total iron total sulfur 0 02 16 wt acid volatile monosulfide s av disulfide s di 70 of total sulfur sulfate s so 4 and organosulfur s org isotopic composition of separated sulfur phases 34 s di av up to 49 and mineralogy morphology and paragenesis of sulfide minerals mineralogy morphology 34 s di av and 34 s org have a distinctive relation reflecting variable and unique depositional and early diagenetic conditions in the green river lakes when the lakes were brackish dissimilatory sulfate reducing bacteria in the sediment produced h 2 s which initially reacted with labile iron to form pyrite framboids and more gradually with organic matter to form organosulfur compounds during a long lived stage of saline lake water the amount of sulfate supplied by inflow decreased and alkalinity and ph of lake waters increased substantially extensive bacterial sulfate reduction in the water column kept lake waters undersaturated with sulfate minerals a very high h 2 s so 4 ratio developed in stagnant bottom water aided by the high ph that kinetically inhibited iron sulfidization progressive removal of h 2 s by coeval formation of iron sulfides and organosulfur compounds caused the isotopic composition of the entire dissolved sulfur reservoir to evolve to 34 s values much greater than that of inflow sulfate which is estimated to have been 20 a six million year interval within lake uinta cores records this evolution as well as smaller systematic changes in 34 s interpreted to reflect 100 000 year lake level cycles when porewater was exceptionally reducing unstable fes phases eventually recrystallized to pyrrhotite during diagenesis a much later reaction related to weathering altered pyrrhotite to marcasite

isotopic composition of precipitation in central iowa abstract the isotopes of hydrogen and oxygen have been used extensively as indicators of groundwater age 3h and paleotemperature of groundwater recharge 18o 16o 2h 1h however comparisons of values in groundwater with those in recent precipitation are few this study describes and interprets the isotopic composition of precipitation in central iowa for the year 1992 an unusually mild winter driven by south westerly flow of the jet stream was followed by an unusually cool and predominantly dry summer that was caused by a persistent northwesterly flow in the upper atmosphere temperature was below normal 9 0 c precipitation was above normal 868 4 mm and was mostly derived from a gulf of mexico moisture source fifty one precipitation samples were collected from 37 events and analyzed for hydrogen and oxygen isotopes tritium activities ranged from 0 to 44 tritium units tu and the weighted mean 3h activity was 11 02 tu a value consistent with international atomic energy agency iaea data anomalously high 3h activities suggested input of technogenic 3h weighted mean values of 18o and 2h were 8 02 and 53 62 respectively and the equation of the local meteoric water line was 2h 9 26 18o 4 65 weighted mean 18o and 2h values from the gulf pacific moisture source 10 80 74 82 were more depleted than those ascribed solely to a gulf of mexico moisture source 7 24 47 39 seasonal differences in temperature primarily controlled these differences in isotopic composition

permian paleoclimate data from fluid inclusions in halite abstract this study has yielded surface water paleotemperatures from primary fluid inclusions in mid permian nippewalla group halite from western kansas a cooling nucleation method is used to generate vapor bubbles in originally all liquid primary inclusions then surface water paleotemperatures are obtained by measuring temperatures of homogenization to liquid homogenization temperatures ranged from 21 c to 50 c and are consistent along individual fluid inclusion assemblages indicating that the fluid inclusions have not been altered by thermal reequilibration homogenization temperatures show a range of up to 26 c from base to top of individual cloudy chevron growth bands petrographic and fluid inclusion evidence indicate that no significant pressure correction is needed for the homogenization temperature data we interpret these homogenization temperatures to represent shallow surface water paleotemperatures the range in temperatures from base to top of single chevron bands may reflect daily temperatures variations these permian surface water temperatures fall within the same range as some modern evaporative surface waters suggesting that this permian environment may have been relatively similar to its modern counterparts shallow surface water temperatures in evaporative settings correspond closely to local air temperatures therefore the permian surface water temperatures determined in this study may be considered proxies for local permian air temperatures

the chemical and hydrological evolution of an ancient potash forming evaporite basin as constrained by mineral sequence fluid inclusion composition and numerical simulation the chemical evolution of the brine in a potash evaporite basin has been investigated by x ray microanalysis of frozen primary inclusions trapped in halite a computer program based on thermodynamic equilibrium and mass balance principles has been used to simulate evaporation paths the comparison between the results of calculations the observed mineralogy and mineral sequence and the solute content in fluid inclusions has placed constraints on the hydrological evolution of the basin the upper eocene basin of navarra southern pyrenees spain began as a marine basin evolving from a moderate to a high degree of restriction depositing first a basai anhydrite horizon and then a thick sequence of massive halite an additional inflow of cacl2 in the basin during seawater evaporation is proposed as the process responsible for the sulfate depletion required for sylvite instead of mg sulfates to form mixing of seawater with continental waters bacterial sulfate reduction and in situ dolomitization are discarded the basin subsequently closed to the sea and evolved with decreasing volume alternating bands of clays halite sylvite and then clays halite carnallite were deposited under the influence of seasonal continental recharge before reaching total desiccation the residual brine was diluted by continental water the basin then evolved under an endoreic regime where continental recharge and the recycling of previously formed halite led to deposition of alternating beds of clays and halite

isotope hydrology and geochemical modeling new insights into the recharge processes and water rock interactions of a fissured carbonate aquifer gran sasso central italy the goal of this paper was to characterize the recharge process and water rock interactions in a regional homogeneous fractured carbonate aquifer in the mediterranean environment gran sasso central italy through isotope data 2h 18o and 13c dic collected between 2006 and 2010 samples were collected from the springs of the gran sasso aquifer and from the underground nuclear physics laboratories located within the aquifer additionally the hydrochemical data and the reference hydrogeological frameworks of previous studies have been used as a starting point for the geochemical modeling the gran sasso aquifer which is bounded by terrigenous and clastic units acting as aquitards accommodates a uniquely broad regional groundwater which feeds springs mainly at its border with high steady discharge in total these springs discharge of more than 18 m3 s at a local scale for the aquifer core and at a regional scale for the overall aquifer 2h 18o and 13c dic isotope data the geochemical inverse modeling through phreeqc and the 13c dic fractionation modeling through netpath 2 0 show the following 1 clear processes of evaporation and related isotope enrichment may be ruled out 2 groundwater flow is active and extends to the overall aquifer without clear signs of layering and partitioning 3 groundwater flowpaths radiate from the core toward the periphery 4 in l aquila plain gran sasso groundwater mixes with shallow quaternary water at a ratio of one half 5 the main geochemical processes are the dissolution of calcite and dolomite and in some cases ion exchange occurs mg2 and so42 release ca2 adsorption 6 in the less mineralized recharge groundwater the 13c dic value is influenced by the 13c dic value of rainfall while in more evolved groundwater the final 13c dic value is reached by fractionation during the flowpaths indicating a lengthy interaction with limestone

evaluation of geochemical and hydrogeological processes by geochemical modeling in an area affected by evaporite karstification the ebro valley in the outskirts of zaragoza ne spain is severely affected by evaporite karstification leading to multiple problems related to subsidence and sinkhole formation in this work a combination of inverse mixing mass balance and forward reaction path geochemical calculations is applied for the quantification of the main karstification processes and seasonal variations in this area the obtained results prove the suitability of the applied methodology for the characterization of similar problems in other areas with scarce geological and hydrogeological information the hydrogeology and hydrochemistry of the system can be mainly attributed to the mixing of variable proportions of concentrated groundwater from the evaporitic aquifer and more dilute water from the overlying alluvial aquifer the existence of a good connection between these aquifers is supported by 1 the fast changes in the hydrochemistry of the karst aquifer related to recharge by irrigation and 2 the deduced input of evaporitic groundwater in the alluvial materials the evolution in some parts of the alluvial evaporitic aquifer system is clearly dominated by the seasonal variations in the recharge by dilute irrigation waters up to 95 of water volume in some sinkhole ponds whereas other points seem to be clearly determined by the hydrochemistry of the concentrated evaporitic aquifer groundwater up to 50 of the water volume in some springs the following reactions previous or superimposed to mixing processes explain the observed hydrochemistry in the studied area dissolution of halite naci gypsum caso4 2h 2 o anhydrite caso4 and dolomite camg co3 2 co2 b input and degassing and calcite caco3 dissolution precipitation the modeling results suggest the existence of a large spatial variability in the composition of the evaporitic groundwater mainly caused by large differences in the availability of halite in contact with the groundwater active subsidence associated with halite dissolution is expected to continue in the study area together with the episodic increase of gypsum dissolution associated with the input of dilute irrigation waters c 2015 elsevier b v all rights reserved

geochemical conditions of deposition in the upper devonian prypiac and dnipro donets evaporite basins belarus and ukraine abstract earlier studies of individual fluid inclusions in salt minerals of some devonian evaporite basins showed that the brines in those basins were of chloride type with a high concentration of ca2 the genetic significance of this occurrence was subject to different interpretations we have studied in detail samples taken from the east european dnipro donets and prypiac evaporite basins aiming to establish the chemical composition of fluid inclusions in studied evaporites and then using other geochemical information to establish a geochemical model of the devonian evaporite basins our study showed that salt deposition in the devonian dnipro donets and prypiac evaporite basins was because of intensive evaporation of mainly marine brines of chloride type with a relatively high ca2 content in turn the ratios between na k and mg corresponded to ratios in recent marine brines salt minerals precipitated in bottom water conditions the occurrence of one phase fluid inclusions indicates the temper

extremely acid permian lakes and ground waters in north america evaporites hosted by red beds red shales and sandstones some 275 265 million years old extend over a large area of the north american mid continent1 they were deposited in non marine saline lakes pans and mud flats2 settings that are typically assumed to have been alkaline here we use laser raman microprobe analyses of fluid inclusions trapped in halites from these permian deposits to argue for the existence of highly acidic ph 1 lakes and ground waters these extremely acidic systems may have extended over an area of 200 000 km2 modern analogues of such systems may be natural acid lake and groundwater systems ph 2 4 in southern australia3 4 5 6 7 8 9 both the ancient and modern acid systems are characterized by closed drainage arid climate low acid neutralizing capacity and the oxidation of minerals such as pyrite to generate acidity the discovery of widespread ancient acid lake and groundwater systems demands a re evaluation of reconstructions of surface conditions of the past and further investigations of the geochemistry and ecology of acid systems in general

temperature as a marker for karstic waters hydrodynamics inferences from 1 year recording at la peyrere cave ariege france abstract we present temperature measurements recorded at a 15 min time step between october 2002 and april 2003 inside the la peyrere cave baget karstic system central pyrenees on six 0 01 c sensitivity sensors distributed on the whole recognized cave down to a depth of 57 m rainy events are associated to a steep signal of a few hundredth to a few tenth of degrees in amplitude starting 1 h to one day after rain and with a sign depending mostly of the outside temperature the temperature signal does not correlate well with the rainfall while the water level does with a maximum water rising rate 2 5 h after rain the spectral density of the temperature signal displays one peak at a period of 3 days which is also present in the rain signal and which is likely to be related to climatic parameters and a broad smooth zone of spectral energy close to a 1 day period by comparing a superficial and a deepest group of sensors we note that the flood signal is more pronounced on the deepest sensor group whatever the outside temperature and that the annual temperature variation is also larger on this sensor group this could indicate that rain water flows in the cave through its base and explain the development in depth of the cave due to the arrival of water with different temperatures and mineralizations at different levels double diffusive convection is likely to be triggered in the cave we suggest that the onset of convection could be associated to the oscillations observed on the temperature signal at the onset of the flood

biological marker composition of typical source rocks and related crude oils of terrestrial origin in the people s republic of china a review abstract typical source rocks and related crude oils of terrestrial origin in china come from five major environments a sedimentary formations in large lake basins in china s interior plate b lacustrine clastic rocks in fault subsidence basins c saline lake strata in fault subsidence basins d lagoonal lacustrine volcano clastic rocks in intermontane basins and e paralic coal bearing formations of the platform facies each has its specific biomarker characteristics as follows 1 environment a is poor in gammacerane and triterpane of higher plant origin 2 environment b contains abundant biomarkers especially hopanoid and steroid hydrocarbons with some triterpanes of higher plant origin 3 environment c has extremely high amounts of phytane and series of s compounds with high ratios of phytane pristane and gammacerane c30 hopane and sometimes high even carbon predominance of n alkanes 4 environment d contains abundant isoprenoid alkanes and carotanes carotane and carotane and 5 environment e is rich in biomarkers of high plants such as diterpenoid and aromatized terpenoid hydrocarbons

modelling of the functioning of karst aquifers with a reservoir model application to fontaine de vaucluse south of france summary this work deals with a rainfall discharge model applied to a well known karst aquifer a new approach is developed in order to minimize the fitting parameters here some of the model parameters do not result from a simple fitting as it was the case with earlier models i e some of them were assessed from the hydrograph analysis the conceptual model of the functioning is based on a production function based on a simple calculation of effective rainfall and a transfer function consisting of two reservoirs a slow discharge reservoir transfers the low flow and a rapid discharge reservoir feeds the high flow the model has three fitted parameters plus one for its initialisation three parameters are deduced from the hydrograph analysis over the entire time series for example the recession coefficient of the slow discharge reservoir is determined from the hydrodynamic analysis of the recession mangin a 1975 contribution a l etude hydrodynamique des aquiferes karstiques 3eme partie constitution et fonctionnement des aquiferes karstiques annales de speleologie 30 1 210 124 this model was tested over a ten years period on the fontaine de vaucluse french karst system the first hydrological year is used for fitting the model the nine other cycles validate the modelling the good quality of the model is proved by the nash criterion of 92 3 on the validation period moreover the simulation results were validated by a statistical analysis of measured and simulated time series the model successfully simulates both the high and low flow at the same time also it estimates the water volumes available in the different parts of the aquifer and it proposes a management tool capable of predicting the evolution of the discharge in different climate conditions

karst biogeochemistry in china past present and future the dissolution and deposition processes of carbonate rock called co2 water carbonate rock interaction are controlled by complex interactions among the biosphere pedosphere atmosphere and lithosphere the interactions between biogenic activity and the co2 water carbonate rock system dissolution and precipitation of carbonate rocks element cycles and so forth had been named karst biogeochemistry in order to reveal their internal control mechanism over space and time chinese researchers undertook an in depth exploration of their interrelationships the main results of karst biogeochemistry in china can be summarized as follows i biogenic activity plays an important role in regulating dissolution and precipitation of carbonate rocks ii biogenic metabolic effects are involved in the positive or negative modulation of 13c 15n and the cycling of other elements iii co2 exchange during carbonate rock dissolution and precipitation which is mainly due to photosynthesis results in the accumulation of organic matter and iv primary karst biogeochemistry models have been established to evaluate carbon and nitrogen cycling in addition to these findings future studies should increasingly focus on the following topics i the apparent stability and transformation of dissolved organic carbon caused by microbial activities need to be clarified ii the temporal spatial scales of microbial biomineralization and the accompanying variances of karst biogeochemical cycles should be investigated to comprehensively understand the transformations and transport of substrates from biological activity in the co2 water carbonate rock system iii regional global scale models on karst biogeochemical cycles should be developed for the study of large small scale spatial and temporal variance on karst biogeochemical cycles iv new advanced techniques and methods are required and should be applied for the karst studies involving mathematics hydrochemistry isotope chemistry geology biology and so forth

evaluating seawater chemistry from fluid inclusions in halite examples from modern marine and nonmarine environments fluid inclusions from marine halites have long been studied to determine the chemical composition of ancient seawater chemical analyses of the major ions in fluid inclusions in halites from the solar saltwork of great inagua island bahamas and from the supratidal sabkha baja california mexico show that modern marine halites faithfully record the chemical signature of seawater the major ions in great inagua and baja california fluid inclusions display distinctive linear trends when plotted against one another ie na k and so42 vs mg2 and cl which track the evaporation path of seawater as it evolved during the crystallization of halite these evaporation paths defined for the major ions by fluid inclusions in halite overlap findings of computer simulations of the evaporation of modern seawater by the harvie moller and weare hmw computer program the close match between the hmw seawater evaporation paths and the great inagua fluid inclusion data is not surprising considering the carefully controlled inflow evaporation and discharge of seawater at the great inagua saltwork the major ion chemistry of fluid inclusions from the baja california halites matches the hmw seawater evaporation paths in most respects but one baja fluid inclusion has lower concentrations of mg2 than evaporated seawater nonmarine inflows and syndepositional recycling of preexisting salts in the baja california supratidal setting were not large enough to override the chemical signature of evaporating seawater as the primary control on the baja fluid inclusion compositions fluid inclusions in halites from the nonmarine qaidam basin qinghai province western china have a distinctly different major ion chemical signature than does global seawater the fluid inclusion chemistries from the qaidam basin halites do not lie on the evaporation pathways defined by modern seawater and can clearly be differentiated from fluid inclusions containing evaporated seawater if fluid inclusions in halites from modern natural settings contain unmistakable samples of evaporated seawater then evaluation of the chemistry of ancient seawater by chemical analysis of fluid inclusions in ancient marine halites by means of the same approach should be valid

chemical and isotopic δ18o δ2h δ13c 222rn multi tracing for groundwater conceptual model of carbonate aquifer gran sasso infn underground laboratory central italy summary a hydrochemical and isotope study was conducted on the drainage waters of an underground laboratory located inside the gran sasso massif central italy the study was expected to improve the conceptual model of groundwater circulation at the base of an over 1000 thick unsaturated zone in the gran sasso partitioned karst aquifer this lithostratigraphically and tectonically complex aquifer is typical of africa europe thrust and fold collision belt in the mediterranean area in this case investigations on water rock interactions during recharge in complex aquifers overlaid by a thick unsaturated zone have been made thanks to the strategic location of the gran sasso underground laboratories located in the core of a huge carbonate aquifer knowledge of the local basic hydrogeological setting was the starting point for a detailed hydrogeochemical and isotopic study which was carried out at the aquifer scale and at the fine scale in the underground laboratories the water rock interaction processes were investigated both spatially and in temporal sequences analysing recharge waters and groundwater in the underground laboratories by multitracing techniques including major ions and 18o 2h and 13c stable isotopes use of 222rn provides information on transit time in the aquifer processes proved to be typical of carbonate rocks with clear influence of vertical movement of water on chemical physical parameters through the unsaturated zone conversely in the saturated zone these processes proved to be dominantly affected by local geological structural conditions a conceptual model with dual flow velocity is proposed directly related to the local geological structural setting 222rn decay enables to calculate an effective velocity of around 10 m day for the fracture network through the sequence of less permeable dolomites and underlying limestone lag time between recharge and chemical changes in the saturated zone testifies to an effective velocity of about 35 m day for fast flow through recent and active extensional faults

delineating the karstic flow system in the upper lost river drainage basin south central indiana using sulphate and δ34sso4 as tracers abstract a karstic flow system in the upper lost river drainage basin in south central indiana usa was investigated using so4 concentration and 34sso4 as tracers the flow system was characterized as vadose flow and phreatic diffuse flow vadose flow samples were collected from 7 epikarstic outlets after storm events phreatic diffuse flow samples were collected from the orangeville rise the major emergence point for the drainage basin during the base flow periods discharge from the orangeville rise was constant during the base flow periods but showed large variations in flow rate 0 3 11 7 m3 s so4 concentration 11 220 mg l and 34sso4 5 2 to 15 0 after storm events due to the mixing of rain vadose flow and phreatic diffuse flow in the conduits that feed the orangeville rise sulphate concentrations and 34sso4 were unique in vadose flow sso4 13 24 mg l 34sso4 1 9 to 3 8 and phreatic diffuse flow so4 220 mg l 34sso4 15 0 mean so4 concentration of rainwater in the study area was measured as 1 8 mg l using a 3 component mixing model for water in the karstic conduits the mixing ratios of rain 16 5 vadose flow 58 5 and phreatic diffuse flow 25 0 components were calculated in the orangeville rise discharge these mixing ratios attained using so4 concentration as a tracer indicated the important role of the vadose zone as a water storage area in karst aquifers

the ages of large amplitude coastal seiches on the caribbean coast of puerto rico using a process denoted here as the empirical mode decomposition and the hilbert spectral analysis the ages of the seiches on the caribbean coast of puerto rico are determined from their dispersion characteristics with respect to time the ages deduced from this method are less than a day therefore the seiches could be locally generated

water movement in desert soil traced by hydrogen and oxygen isotopes chloride and chlorine 36 southern arizona abstract understanding soil water movement is important for water resource management and for analyzing pollutant transport in the vadose zone seasonal variations in shallow soil profiles may have profound effects on deep soil water and solutes we have investigated seasonal soil water movement in the top meter of undisturbed desert soil in the southern arizona using 2 h 18 o cl and bomb 36 c1 six soil profiles were sampled from a young terrace holocene during 1991 to 1992 on a seasonal basis one soil profile was sampled from an older terrace latest pleistocene in october 1992 and one from a yet older fan surface late pleistocene in march 1992 the results indicate that repeated seasonal cyclic movement of soil water in the top 60 80 cm active zone tends to produce a consistent stable isotope composition for the soil water below the active zone in different seasons the deep 18 o on the oldest surface is about 6 heavier than on the younger surfaces probably resulting from greater evaporative loss due to the larger proportion of fines in the older soil this deep isotopic composition is closely related to the composition of the local average annual precipitation an annual average evaporation rate of 35 mm year 1 was estimated using a steady state diffusion model whereas the actual regional evapotranspiration rate is 175 250 mm year 1 this suggests that about 80 of the soil water is lost through transpiration and first stage evaporation before quasi steady state is reached the long term average infiltration rate below the active zone is about 4 mm year 1 for the younger terrace based on both chloride mass balance and bomb 36 cl and 0 02 mm year 1 for the older terrace and the fan surface based on chloride mass balance the correlation between the deep 18 o the reduction of downward flux and the surface age suggests that increasing soil development has resulted in a significant decrease of soil water infiltration and hence an increase in evaporation and surface runoff

environmental tritium and 18o applied in a hydrological study of the wairau plain and its contributing mountain catchments marlborough new zealand abstract isotope data tritium and 18 o for rivers and ground water acquired since 1968 are combined with geological hydrological and hydrochemical evidence to determine sources and flow patterns of ground water in gravel aquifers of the wairau coastal plain and its southern tributary valleys determination of the components of groundwater origin depends on a strong west east gradient of 18 o concentration between mountain catchment precipitation feeding rivers flowing to the plain and rainwater falling directly on the plain the main aquifer is postglacial alluvial material deposited by wairau river deriving its water from that river locally infiltrated precipitation contributes at most only a few percent to the flow in the shallowest gravels downstream of the infiltration zone in the south of the plain the unconfined aquifer comprises material deposited during the last glaciation its ground water has both local precipitation and inflow from southern tributary streams as appreciable sources the main aquifer is confined near the coast where it is overlain by up to 60 m of marine sediments deposited during postglacial marine transgression and subsequent coastal progradation tritium concentrations show that ground water in the shallowest geological stratum rapaura gravels reaches the confined zone boundary less than 1 year after recharge from the river with much shallow flow being discharged at the surface just upstream of the boundary in contrast ground water in the underlying unit speargrass gravels requires at least 10 years to reach this point analysis of tritium concentrations in the confined zone shows a central zone through which the faster flowing rapaura component dominates as far as the coast but also areas to the north and south where ground water in the rapaura gravels has a dominant older component the combined evidence reveals that the confined ground water is leaking into the overlying sediments allowing water to flow from the lower speargrass gravels into the rapaura gravels because wairau river is the dominant source of ground water for the main aquifer its response to bomb tritium input to its mountain catchments is given detailed consideration much of the river water derives promptly from bare catchment areas but the analysis suggests that about 50 is retained for about 8 years on average before release to the river large deposits of scree in higher lying formerly glacial catchments appears to be the major factor in the surprisingly large quantity of stored water implied by this result

a four component mixing model for water in a karst terrain in south central indiana usa using solute concentration and stable isotopes as tracers the study area lies in a highly karstified carbonate terrain in south central indiana sinkholes conduits and caves form large secondary pathways for the subsurface flow as a result the discharge from a main emergence point for the subsurface flow system the orangeville rise quickly responds to the storm events and shows wide variations in flow rate water chemistry and stable isotopic compositions these responses are attributed to the mixing of water in secondary pathways in the study area recharge occurs through the thick mantled karst plain and the sinkhole plains and the role of soil layer and epikarst in the recharge process is of great importance rain dic 2 hco3 mg l 13cdic 7 soil water dic 544 hco3 mg l 13cdic 14 7 epikarstic water dic 224 hco3 mg l 13cdic 13 6 and phreatic diffuse flow water dic 299 hco3 mg l 13cdic 11 8 generally showed unique and constant dissolved inorganic carbon dic and 13cdic values over time using dic and 13cdic as tracers a four component mixing model was established for the karstic flow system by constructing the discharge hydrograph separation curves the mixing ratio of each component rain 10 6 soil 3 1 epikarstic 52 3 and phreatic 34 0 water was determined for the orangeville rise discharge over the testing period of 104 h after the storm event of 10 4 90 vadose water occupied 55 4 of spring discharge and this demonstrates the importance of the unsaturated zone especially the epikarst in the karstic flow systems

infiltration mechanisms related to agricultural waste transport through the soil mantle to karst aquifers of southern indiana usa abstract a hydrogeological study was conducted during the 1991 1992 water year in the clay soil mantled portion of a limestone terrain in southern indiana the purpose of the study was to investigate the modes of soil water infiltration contributing to rapid transport of nitrate to the saturated zone the 1 year cycle profiles of nitrate concentration vs time show a consistent increase of nitrate at various depths in the unsaturated zone during the period of investigation the increase of nitrate in soil water is attributed to the rapid flushing of the inorganic fertilizers from the fields after the area received sufficient rainfall in late fall the investigation also showed a major movement of nitrate in quick pulses through the unsaturated zone rather than a slow uniform recharge immediately after a major storm event the asymmetric profiles of nitrate concentration vs depth point to the existence of preferential flow through macropores in the clay soil mantle above the bedrock soil water transport between storm events is by matrix type flow nitrogen isotopes were analyzed for representative groundwater samples collected before and immediately after fertilization of fields in the summer 1991 the 615n values of the samples did not show any major shift in nitrate sources between the sampling periods the summer of 1991 was extremely dry prohibiting vertical transport of nitrate from the fields to the groundwater system any change in nitrate concentration in groundwater during this time is attributed to the mixing through lateral flow within the aquifer

stable chlorine isotopes in phanerozoic evaporites abstract modern seawater has a uniform 37cl value 0 0 with an exception in the upper current of the bosphorus 0 4 marine halite ranging in age from cambrian to miocene has 37cl values of 0 0 0 9 with most of the data in the range 0 0 0 5 mean 37cl values differ measurably between basins with no evident relationship to basin size or to age smaller evaporite bodies have the largest 37cl ranges potash facies halite has mean 37cl values lower than those of halite facies salt in the east siberia and zechstein basins the bulk 37cl of bedded halite preserving sedimentary textures cannot be shifted measurably after deposition under plausible natural conditions during the phanerozoic a detectable change in the 37cl values of the oceans is unlikely as a result of cl fluxes to and from the mantle and evaporites in halite the values of 37cl that cannot be explained by fractionation occurring on crystallization are best explained by the addition of non marine cl with 37cl 0 0 to evaporite brine

geochemistry of early triassic seawater as indicated by study of the rot halite in the netherlands germany and poland abstract study of three halite sections in the rot basin from the eastern netherlands twente rijn 382 borehole central germany mardorf 6 borehole and western poland o no ig2 borehole shows that the 34 s values in rot sulphates of studied samples 27 14 31 98 are characteristic of marine sulphates of late early triassic these values fit in the rot event shift described in the literature the bromine content in halite is 32 158 ppm in the dutch and polish sections relics of sedimentary structures chevron and hopper are recorded in halite grains these structures contain fluid inclusions that were analysed using the ultramicrochemical method of petrichenko petrichenko o i 1973 metody doslidzhennya vkluchen v mineralakh galogennykh porid kiev naukova dumka 92 pp in the german section no sedimentary halite structures occur because the pressure in the inclusions in recrystallized halite is only slightly greater than atmospheric pressure these inclusions are presumed to be early diagenetic in origin the analysis of individual brine inclusions both in sedimentary and diagenetic forms of halite shows that the rot brines correspond to the na k mg cl so 4 so 4 rich chemical type i e the same type that characterises modern seawater however the rot brines differ from the composition characteristic of modern concentrated seawater by a decrease in the content of sulphate ion and an increase in the content of potassium ion on a janecke diagram the points of the brine composition during deposition of rot halite in poland germany and the netherlands only show a small range this suggests a stable composition of basinal brines during the deposition of the halite at the same time the relative content of sulphate ion in the lower triassic rot basin was slightly lower than that in upper permian evaporite basins but higher than that in lower and middle permian and middle and upper triassic evaporite basins the implication is that the content of sulphate ion in seawater was subject to changes in permian and triassic times

geochemistry of dissolved inorganic carbon and carbonate weathering in a small typical karstic catchment of southwest china isotopic and chemical constraints abstract the sources of dissolved inorganic carbon dic and rock weathering processes were studied in the houzhai catchment a typical karstic catchment in the changjiang river basin southwest china the carbon isotopic compositions 13 c dic of dic in the samples collected from the catchment vary from 13 5 to 6 9 with a mean value of 9 8 the dic in the catchment is thereby considered to be mainly derived from soil co 2 and weathering of carbonate rocks the dic concentrations and the 13 c dic values show pronounced seasonal variations with the lowest values being observed during the high flow season from may to october the logpco 2 values in the waters were positively correlated with the dic contents and negatively correlated to the saturation index of calcite sic and 13 c dic values these observations indicate that co 2 derived from organic matter oxidation plays an important role in the dissolution of carbonate for this typical karstic environment based on a chemical mass balance the weathering rate of carbonate rocks in the houzhai catchment was estimated to be approximately 133 t km 2 year or 584 10 3 mol km 2 year in terms of co 2 consumption rate which is higher than the reported values for other rivers in southwest china

paleotemperatures preserved in fluid inclusions in halite a variety of paleoclimate proxy records allow determination of relative warming or cooling however if we are to understand climate change quantification of past temperature fluctuations is essential our research indicates that fluid inclusions in halite can yield homogenization temperatures that record surface brine temperatures at the time of halite precipitation to avoid problems with stretching leaking and initial trapping of air samples with primary single phase liquid fluid inclusions are chilled in a freezer to nucleate vapor bubbles we tested the reliability of this method of obtaining fluid inclusion homogenization temperatures using modern salts precipitated at badwater basin death valley california homogenization temperatures correlate well with measured brine temperatures the same method is applied to fluid inclusions in pleistocene halite from a core taken at the same location in death valley results are at several scales recording diurnal temperature variations seasonal temperature fluctuations and longer term warming and cooling events that correlate with major changes in the sedimentary environment related to climate this technique is uniquely instrumental for paleoclimate studies because it offers actual not just proxy paleotemperature data 27 refs 17 figs

a kinetic difference between 12c and 13c bound oxygen exchange rates results in decoupled δ18o and δ47 values of equilibrating dic solutions

geochemical and isotopic studies of groundwater conditions in the densu river basin of ghana the densu river basin drb is an important agricultural area in ghana and has a high population density water shortages have occurred in the basin due to drying out of surface water heavy pollution and low yield in most of the production wells which are crucial factors restricting sustainable socioeconomic development this study was carried out to investigate the geochemical characteristics and evolution as well as recharge processes in the drb system with regard to the tectonics geomorphology lithology and flow system it mainly used hydrochemistry environmental isotopes and a series of comprehensive data interpretation e g statistics ionic ratios and piper diagram to obtain a better understanding of the functioning of the system the following hydrochemical processes were identified as the main factors controlling the water quality of the groundwater system weathering of silicate minerals dissolution ion exchange and to a lesser extent evaporation which seems to be more pronounced downgradient of the flow system as groundwater flows from the recharge to discharge areas chemical patterns evolve in the order of ca2 hco3 ca2 mg2 hco3 to ca2 na cl ca2 na hco3 and na cl according to lithology the environmental isotope 18o 2h 3h measurements further revealed that groundwater in the drb was a relatively well mixed system as evidenced by the encoded narrow range of values however deviation from the rainwater signature indicates combined local processes such as direct percolation through preferential channels evaporation and probable surface water and anthropogenic contribution to the system

characteristics of water stable isotopes and hydrograph separation in baishui catchment during the wet season in mt yulong region south western china glaciers are of crucial importance for the livelihood of the local populations which depend on their meltwater for water and energy supplies for this reason seasonal variations of oxygen 18 of glacial stream water and their sources within a small glacial catchment in south western china were investigated during the wet season the results showed significant difference of oxygen 18 existed among meltwater rainwater ground water and stream water and significantly seasonal variation of precipitation occurred during the observed period the streamflow of baishui catchment was separated into components of ice snowmelt and precipitation using oxygen 18 as shown by the result of the two component mixing model on average 53 4 of the runoff came from ice snowmelt during the wet season whereas the remaining 46 6 were contributed by precipitation in the catchment according to monthly hydrograph the contribution of snow and glacier meltwater varied from 40 7 to 62 2 and that of precipitation varied from 37 8 to 59 3 in wet season uncertainties for this separation were mainly caused by the variation of tracer concentrations the roles of glacier and snow meltwater should be noticed in water resource management in those glacial regions in south western china copyright c 2012 john wiley sons ltd

identification of a karst system s intrinsic hydrodynamic parameters upscaling from single springs to the whole aquifer for water management purposes information about an entire aquifer system is generally more important than information about a specific spring since a karstic aquifer system might drain to several outlets conclusions derived from a single spring can be misleading for characterization and modeling in this study we apply a conceptual model to an alpine dolomite karst system in austria the particular challenge was that several small springs with strongly varying hydrological behavior and diffuse flow into surrounding streams drain this system instead of applying the model to a single spring it was calibrated simultaneously to several observations within the system aiming to identify the karst system s intrinsic hydrodynamic parameters parameter identification is supported by modeling the transport of water isotopes 18o the parameters were transferred to the whole system with a simple upscaling procedure and a sensitivity analysis was performed to unfold influence of isotopic information on parameter sensitivity and simulation uncertainty the results show that it is possible to identify system intrinsic parameters but the sensitivity analysis revealed that some are hardly identifiable only by considering uncertainty reasonable predictions can be provided for the whole system including isotopic information increases the sensitivity of some intrinsic parameters but it goes along with a sensitivity decrease for others however a possible reduction of prediction uncertainty by isotopic information is compensated by deficiencies in the transport modeling routines

paleotemperatures from fluid inclusions in halite method verification and a 100 000 year paleotemperature record death valley ca abstract maximum homogenization temperatures of fluid inclusions thmax in halite laboratory grown crystals and modern samples death valley ca match maximum brine temperatures during halite precipitation maximum brine temperatures during halite precipitation in death valley late april 1993 34 4 c agree with thmax 34 c and correlate well with average maximum air temperatures in april 31 3 c and may 37 6 c thmax may be used for paleoclimate interpretations based on the close relationship between saline lake temperatures and average air temperatures from modern settings lower homogenization temperatures demonstrably below the temperatures at which halite grew are interpreted to reflect collapse of some fluid inclusion walls due to the pressure difference between the inside and outside of inclusions by only using thmax the problems of anomalously low homogenization temperatures due to possible collapse of fluid inclusions are avoided halite samples from 30 stratigraphic intervals 90 to 0 m 100 to 0 ka core dv93 1 death valley ca were used to measure homogenization temperatures of fluid inclusions virtually all homogenization temperatures from core dv93 1 are below the modern thmax of 34 c halite precipitation late april 1993 lacustrine halites deposited in a perennial saline lake 35 to 10 ka have thmax between 19 c and 30 c which suggests brine temperatures approximately 4 c to 15 c below modern late april values ephemeral saline lake halites precipitated 60 to 35 ka have thmax between 23 c and 28 c 6 to 11 c below modern values the highest thmax value in the 100 ka record up to 35 c is from a halite sample formed approximately 100 ka in a climate regime somewhat colder than the modern

modelling the hydrologic functions of a karst aquifer under active water management the lez spring a rainfall discharge model is applied to an aquifer characterized by active groundwater management the lez karst aquifer in the south of france groundwater is withdrawn by pumping in the main drain 400 m upstream from the main spring and 48 m below the aquifer overflow level a reservoir model was developed to characterize the functioning of this aquifer it is based on a conceptual model of the karst aquifer that takes into account flow through both the saturated zone and the unsaturated infiltration zone both rapid and slow flow in the infiltration zone and flow in the saturated zone are modelled since pumping withdraws groundwater from the main drain of the saturated zone modules characterizing various pumping practices are taken into account in the saturated zone reservoir the model simultaneously simulates spring discharge and water levels in the drain which characterize the saturated zone of the karst the groundwater reserves stored in the saturated zone can then be estimated the model can be used for water management since runoff and overflow from the aquifer feeding the lez river depend on the degree of saturation of the aquifer the model could be used for the flood management