relative weathering intensity of calcite versus dolomite in carbonate bearing temperate zone watersheds carbonate geochemistry and fluxes from catchments within the st lawrence and danube river basins 1 calcite and dolomite solubilities in open weathering environments are proportional to pco2 and inversely proportional to temperature and dolomite solubility is progressively greater than calcite below 25 c the continent scale weathering budget reveals the significance of the northern hemisphere nh to globally integrated riverine fluxes of ca2 mg2 and hco3 the nh contributes 70 of the global hco3 flux while only 54 of the riverine discharge we present results of a comparative hydrogeochemical study of carbonate mineral equilibria and weathering fluxes in two nh carbonate rich river basins surface water geochemistry and discharge were determined for headwater streams in michigan and slovenia within the st lawrence and danube river basins michigan watersheds are established atop carbonate bearing glacial drift deposits derived from erosion of paleozoic strata with thick soil horizons 100 300 cm slovenia watersheds drain mesozoic bedrock carbonates in alpine and dinaric karst environments with thin soil horizons 0 70 cm carbonate weathering intensity is a parameter that normalizes river runoff and hco3 concentration to catchment area meq hco3 km 2 s 1 summing calcite and dolomite contributions and is used to gauge the effects of climate land use and soil thickness on organic inorganic carbon processing rates importantly michigan riverine discharge is one tenth of slovenian rivers providing the opportunity to evaluate the kinetics of carbonate mineral equilibration the study rivers are hco3 ca2 mg2 waters supersaturated for calcite at pco2 values in excess of the atmosphere as discharge varies hco3 concentrations differ by less than 20 for any location and mg2 ca2 remains relatively fixed for michigan 0 5 and slovenia streams 0 4 requiring that dolomite dissolution exceed calcite on a mole basis the ability of calcite and dolomite dissolution to keep pace with increased discharge indicates carbonate weathering is limited only by water flux and temperature dependent solubility in these watersheds carbonate weathering intensity in michigan and slovenia exceeds the world average by factors between 2 and 20 and dolomite weathering intensity estimated from riverine mg2 fluxes exceeds the world average by factors between 2 and 15 thus global fluxes of carbonate related weathering products appear heavily skewed toward carbonate bearing environments at higher latitudes with relatively low mean annual temperatures and high discharge

seismicity of the koyna region and regional tectonomagmatism of the western margin india recent findings on the meso cenozoic tectonomagmatism and deep seated anomalous geophysical structures suggest a close linkage between the seismicity of the koyna region the westernghat uplift wg u and associated thermomechanical and fluid activities the wg u seems to be the result of late cretaceous thermal mobilization erosion of the deccan trap cover and superposition of compressional stress the association of seismicity with uplift seems to result from movement of deep seated heat and fluids volatiles along the edges or boundary faults of the uplift because the force required for crustal deformation depends on the relief observed gradients in relief may be attributed to the differential erosion rates and heat inputs due to the time gap of 50 ma in the break ups and plume activities on the eastern and western sides and consequence magmatism further the geology and tectonics strongly indicate that the western margin wm is a relic of a mobile arm ma that included madagascar and which formed a part of the proterozoic mobile belt of greater india fort 85 ma the mobile nature of the wm facilitates mantle upwellings and transient elevation of isotherms at depth raising the possibility of intermittent metamorphism and greater deformation superposition of the ongoing compression and uplift induced forces make local permeability and pore fluid pressure vital in triggering the seismic slip over the peninsular shield certain representative model calculations have been carried out to estimate change in the e m induction characteristics caused by an intermittent hydraulic connectivity the results show a drop in the resistivity which could be a useful monitoring index the close connection of uplift and fluid activity as discussed here seems applicable for other active parts of the south indian shield sis also

water geochemistry of the chaohu lake basin rivers china chemical weathering and anthropogenic inputs abstract as one of the five largest freshwater lakes in china the chaohu lake is polluted by many kinds of pollutants chemical and sr isotopic compositions of river waters in the zhegao river sub catchment have been determined with the main purpose of understanding the contribution of chemical weathering and anthropogenic inputs to solutes the major ion compositions of the river waters are characterized by the dominance of ca2 and hco 3 followed by mg2 and so 4 2 the chemical and sr isotopic analyses indicate that three major reservoirs carbonate silicate and human activities contribute to the dissolved load the calculated results show that the dissolved load is dominated by carbonate weathering the contribution of the anthropogenic inputs is estimated to be from 1 64 to 31 8 with an average of 15 6 demonstrating the strong impacts of human activities on water chemistry the total chemical denudation flux of the zhegao sub catchment is about 127 7 ton km 2 a 1 with carbonate and silicate weathering rates of 97 5 ton km 2 a 1 and 30 2 ton km 2 a 1 respectively

mineralogical hydrogeochemical and isotopic characteristics of the žveplenica sulphide karstic spring trebusa valley nw slovenia sulphide springs in slovenia are very rare and they form a peculiar feature in a carbonate setting the basic geological hydrogeochemical and isotopic characteristics of the veplenica sulphide dolomite spring trebusa valley nw slovenia were investigated along with the geochemical and mineralogical characteristics of the sediment deposited at the spring location geological mapping defined a small structurally and lithologically isolated dolomitic aquifer the major groundwater geochemical composition is hco3 mg2 ca2 indicating dissolution of dolomite the concentration of so42 was very low the groundwater was generally close to saturation with respect to calcite and dolomite geochemical modelling and other analyses indicated sulphur to originate not from gypsum and or anhydrite but from some other sources we suggest the origin of sulphur be the dissolution of volcanogenic sulphidic enrichment in a highly variable ladinian clastic limestone volcanic rock association forming the basis of early carnian cordevolian dolomite from which the spring discharges the measured 13cdic value of 11 9 indicates groundwater with a contribution of degraded organic matter and dissolved inorganic carbon in the aquifer the isotopic composition of oxygen 18oh2o hydrogen dh2o and tritium was 8 1 d 51 4 and 3h 3 64 tu respectively the 18o and d values indicated recharge from precipitation with h2s exsolution while the 3h activity shows groundwater older than 40 years mineralogical and geochemical analysis of sediment showed a typical carbonate mostly dolomite composition which was in agreement with the geochemical and isotopic composition of the groundwater of the spring indicating a deep sourced inorganic form of sulphur such as pyrite

quantification of the daily dynamics of streamflow components in a small alpine watershed in switzerland using end member mixing analysis there is a growing need to improve our understanding of catchment flow generation processes especially in alpine watersheds where the aquatic biodiversity is dependent upon the types of water sources and their seasonal dynamics in order to identify and quantify the potential sources that contribute to stream runoff water samples were collected and discharge was measured other physical variables like electric conductivity and water temperature were also collected twice a day once in the morning and once in the evening these measurements continued for two to four consecutive days in situ measurements were done for temperature electric conductivity and turbidity of water at different temporal scale mass spectrometry was done to analyze silica and sulfate along with chlorine three different water sources were identified based on their physiochemical characteristics glacier melt water quickly routed surface runoff and slowly routed ground water principal component analysis was performed in order to reduce dimensionality of the chemistry data independently in two hydrological years end member mixing analysis was carried out for morning and afternoon data to describe the daily variation of runoff components our study suggests that glacier melt component has a strong daily variation which influences the magnitude and timing of peak flow a sign of early melt and accumulation can be seen in this watershed based on the studied years

crustal accretion beneath the koyna coastal region india and late cretaceous geodynamics abstract in 1967 a major earthquake in the koyna region attracted attention to the hitherto considered stable indian shield the region is covered by a thick pile of deccan lava flows and characterized by several hidden tectonic features and complex geophysical signatures although deep seismic sounding studies have provided vital information regarding the crustal structure of the koyna region much remains unknown the two available dss profiles in the region have been combined along the trend of bouguer gravity anomalies unified 2 d density modelling of the koyna crust mantle suggests a ca 3 km thick and 40 km wide high velocity high density anomalous layer at the base of the crust along the coastline the thickness of this anomalous layer decreases gradually towards the east and ahead of the koyna gravity low the layer ceases to be visible based on the seismic and gravity data interpretation in the geodynamical rheological boundary conditions the anomalous layer is attributed to igneous crustal accretion at the base of the crust it is suggested that the underplated layer is the imprint of the magmatism caused by the deep mantle plume when the northward migrating indian plate passed over the reunion hotspot

major element chemistry of the huai river basin china the chemistry of major ions ca mg na k hco3 so4 cl and si in the water of the huai river basin was studied based on samples from 52 sites from nine different water bodies in july 2008 ions and total dissolved solids tds displayed clear spatial patterns with lower concentrations in the south and higher in the north of the basin the same conditions were also found in the east line of south north water transfer project snwtp in this region the huai river main channel and hongze lake have moderate ion concentrations relative to the whole basin tds concentrations versus the weight ratios of na na ca and ternary ions demonstrate that the southern rivers shi r and pi r are mainly controlled by the weathering of carbonates whereas the northern water systems guo r shaying r nansi lake and its tributaries are dominated by the weathering of evaporites the huai river main channel hongze lake and the east line of snwtp are synergistically influenced by weathering of evaporites and carbonates yet hongze lake and the east line of snwtp are mainly controlled by evaporation and crystallization processes this study also confirmed that the huai river is the geographic division between southern and northern china most rivers of this basin have very high ionic composition relative to the global median and other world rivers the spatial patterns and ionic composition also suggest that intensive anthropogenic activities in northern areas of this basin are well characterized a comparison with who and chinese standards for drinking water indicates that the northern water systems of this basin are not suitable for use as drinking water sources and pollution control should be improved and enhanced in northern areas of the basin crown copyright c 2010 published by elsevier ltd all rights reserved

imaging and observing the electrical moho abstract defining the depth to the base of the crust is of profound importance for understanding and developing theories of the secular variation of our planet including crustal formation and evolution since its discovery 100 year ago the seismic moho is almost ubiquitously used as the crust mantle boundary reference laboratory studies on crustal and mantle rocks suggest that there should be a concomitant step lie change in electrical conductivity an electric moho emoho at the crust mantle boundary we examine resolution properties of electrical and electromagnetic methods for imaging and observing an emoho for three generic models one to represent the archean one for the proterozoic and the third for the phanerozoic we show that in all three cases given the existence in most localities of a conducting lower crust compared to the upper crust and upper lithospheric mantle the problem is difficult and at the edge and often beyond confident resolution for some highly unusual localities however the lower crust is more resistive than the underlying upper mantle and in those cases it is possible to resolve an emoho but very high quality data are required examples of emoho observations around the globe are discussed focussing on the results from a site on the southwestern part of the slave craton northwestern canada

tracing contributions to hydro isotopic differences between two adjacent lakes in the southern tibetan plateau hydrological processes of lakes in the tibetan plateau are an important indicator of climate change due to the high elevation inaccessibility and limited availability of historical observations water budget evaluation of typical lake basins has been inadequate in this study stable isotopes are used to trace the multiple water sources contributing to two adjacent lakes on the north slope of the himalayas gongmo tso and drem tso the two lakes have nearly the same elevation lake area and climatic condition however the isotopic composition of the two lakes presents significant differences qualitative observations attribute the differences to hydrological discrepancies gongmo tso is a through flow lake whereas drem tso is a terminal lake quantitative analyses including water and isotope mass balance modelling clarify the fluxes and isotopic compositions among the various hydrological elements the isotopic composition of input water calculated as the summation of rainfall and upstream runoff is estimated using the local meteoric water line lmwl combined with the time series of lake water isotope values the isotopic composition of evaporation is calculated with a linear resistance model using local meteorological data the results show that drem tso is a closed lake in a hydrological steady state with relatively more enriched lake water isotope values resulting mainly from evaporation in contrast through flow accounts for more than 88 of the water input into gongmo tso the large amount of upstream runoff with lower isotopic composition and enrichment due to evaporation are the major contributions to the observed lake water isotope values isotopic modelling of the two neighbouring lakes is effective for isotopic and hydrological research in this region with limited in situ observations copyright 2013 john wiley sons ltd

ice core evidence of rapid air temperature increases since 1960 in alpine areas of the wind river range wyoming united states 1 site specific transfer functions relating delta oxygen 18 18o values in snow to the average air temperature ta during storms on upper fremont glacier ufg were used in conjunction with 18o records from ufg ice cores to reconstruct long term trends in air temperature from alpine areas in the wind river range wyoming transfer functions were determined by using data collected from four seasonal snowpacks 1989 1990 1997 1998 1998 1999 and 1999 2000 the timing and amount of each storm was determined from an automated snowpack telemetry snotel site 22 km northeast of ufg and 1060 m in elevation below ufg statistically significant and positive correlations between 18o values in the snow and ta were consistently found in three of the four seasonal snowpacks the snowpack with the poor correlation was deposited in 1997 1998 during the 1997 1998 el nino southern oscillation enso an ultrasonic snow depth sensor installed on ufg provided valuable insights into site specific storms and postdepositional processes that occur on ufg the timing of storms recorded at the ufg and cold springs snotel sites were similar however selected storms did not correlate snow from storms occurring after mid october and followed by high winds was most susceptible to redeposition of snow this removal of lower temperature snowfall could potentially bias the 18o values preserved in ice core records to environmental conditions reflecting higher air temperatures and lower wind speeds transfer functions derived from seasonal snow cover on ufg were used to reconstruct ta values from 18o values determined from two ice cores collected from ufg reconstructed air temperatures from the ice core data indicate an increase in ta of 3 5 c from the mid 1960s to the early 1990s in the alpine areas of northwestern wyoming reconstructed ta from the ice core records between the end of the little ice age lia mid 1800s and the early 1990s indicate a ta increase of 5 c the historically reconstructed ta values from the ufg were significantly higher than the global average observed during the 20th century but were in agreement with ta increases observed at selected high altitude and high latitude sites in other parts of the world additional research is required to determine if part of the observed trend toward heavier 18o values in ice from the ufg since the lia and increased ta is due to an increased proportion of snowfall from southerly storm tracks and moisture sources as seems to have been the situation in 1997 1998

application of a bayesian model to infer the contribution of coalbed natural gas produced water to the powder river wyoming and montana the powder river basin prb of wyoming and montana contains significant coal and coal bed natural gas cbng resources cbng extraction requires the production of large volumes of water much of which is discharged into existing drainages compared to surface waters the cbng produced water is high in sodium relative to calcium and magnesium elevating the sodium adsorption ratio sar to mitigate the possible impact this produced water may have on the quality of surface water used for irrigation the state of montana passed water anti degradation legislation which could affect cbng production in wyoming in this study we sought to determine the proportion of cbng produced water discharged to tributaries that reaches the powder river by implementing a four end member mixing model within a bayesian statistical framework the model accounts for the 87sr 86sr 13cdic sr and dic of cbng produced water and surface water interacting with the three primary lithologies exposed in the prb the model estimates the relative contribution of the end members to the river water while incorporating uncertainty associated with measurement and process error model results confirm that both of the tributaries associated with high cbng activity are mostly composed of cbng produced water 70 100 the model indicates that up to 50 of the powder river is composed of cbng produced water downstream from the cbng tributaries decreasing with distance by dilution from non cbng impacted tributaries from the point sources to 10 20 at the montana border this amount of cbng produced water does not significantly affect the sar or electrical conductivity of the powder river in montana copyright 2013 john wiley sons ltd

geochemical evolution of groundwater in the carbonate aquifers of sierra de segura betic cordillera southern spain summary sierra de segura betic cordillera with a total area of over 3000 km 2 is the source of the two principal rivers in southern spain the guadalquivir and the segura due to the orographic effect of these mountains precipitations are considerably more abundant than in nearby lowland areas where the climate is semi arid sierra de segura is constituted of mesozoic and cenozoic sedimentary rocks among which there are thick limestone dolomitic formations which have given rise to extensive outcrops of permeable materials in geomorphological terms there is a large plateau intensively karstified that constitutes the main recharge area discharge takes place via a large number of springs of which the 50 most important add up to a mean spring flow of about 13 500 l s the active geochemical processes in aquifers of sierra de segura with their corresponding time sequence are dissolution of co 2 dissolution of calcite incongruent dissolution of dolomite dedolomitization exsolution of co 2 and precipitation of calcite more evolved water has higher temperature magnesium content and mg ca ratio therefore these parameters can be utilised as indicators of the degree of hydrochemical evolution in addition a good correlation between water temperature and magnesium concentration or mg ca ratio indicates that an increase in temperature accelerates the kinetics of the dissolution of dolomite finally the distribution of the temperatures in the vadose zone determined by atmospheric thermal gradient implies an apparent stratification of the predominant hydrochemical processes and of the groundwater physical and chemical characteristics

mt and reflection an essential combination summary at many localities in the world there have been coincident comprehensive electromagnetic em studies and seismic reflection profiles conducted unfortunately over many more regions the seismic reflection images are interpreted without the constraints afforded by electrical conductivity information this paper is an attempt to convince the reader that a collocated magnetotelluric mt study should in almost every case be made wherever a seismic reflection survey is undertaken examples are shown from six studies in which the em results aided the geological tectonic interpretations of the seismic sections also difficulties with the mt technique are discussed and the interpretations of conducting zones within the lower crust are examined finally a generalised model is proposed for the continental crust that may account for both the reflectivity and conductivity of the zone at the top of the lower crust

chronological refinement of an ice core record at upper fremont glacier in south central north america the potential to use ice cores from alpine glaciers in the midlatitudes to reconstruct paleoclimatic records has not been widely recognized although excellent paleoclimatic records exist for the polar regions paleoclimatic ice core records are not common from midlatitude locations an ice core removed from the upper fremont glacier in wyoming provides evidence for abrupt climate change during the mid 1800s volcanic events krakatau and tambora identified from electrical conductivity measurements ecm and isotopic and chemical data from the upper fremont glacier were reexamined to confirm and refine previous chronological estimates of the ice core at a depth of 152 m the refined age depth profile shows good agreement 1736 10 a d with the sup 14 c age date 1729 95 a d the delta sup 18 o profile of the upper fremont glacier ufg ice core indicates a change in climate known as the little ice age lia however the sampling interval for delta sup 18 o is sufficiently large 20 cm such that it is difficult to pinpoint the lia termination on the basis of delta sup 18 o data alone other research has shown that changes in the delta sup 18 o variance are generally coincident with changes in ecm variance the ecm data set contains over 125 000 data points atmore a resolution of 1 data point per millimeter of ice core a 999 point running average of the ecm data set and results from f tests indicates that the variance of the ecm data decreases significantly at about 108 m at this depth the age depth profile predicts an age of 1845 a d results indicate the termination of the lia was abrupt with a major climatic shift to warmer temperatures around 1845 a d and continuing to present day prediction limits error bars calculated for the profile ages are 10 years 90 confidence level thus a conservative estimate for the time taken to complete the lia climatic shift to present day climate is about 10 years suggesting the lia termination in alpine regions of central north america may have occurred on a relatively short decadal timescale c 2000 american geophysical union less

sr isotope tracing of aquifer interactions in an area of accelerating coal bed methane production powder river basin wyoming sr isotope data on groundwater samples from coal and overlying sandstone aquifers in the eastern powder river basin wyoming demonstrate that the sr isotope ratio effectively identifies groundwater from different aquifers where major ion geochemistry and o and h stable isotope data fail groundwaters from sandstone aquifers have a uniform 87sr 86sr ratio of 0 7126 0 7127 waters from coal seams vary from 87sr 86sr ratio 0 7127 near the recharge area to 0 7151 farther into the basin the distinct sr isotope signatures of sandstone and coal aquifers may reflect different sources of sr in these two rock types sr in sandstones is held primarily in carbonate cement whereas coals contain more radiogenic sr in organic matter the sr isotope ratio is useful in identifying wells that contain mixed waters whether due to well construction or to incomplete aquifer isolation measurement and continued monitoring of the sr isotope ratio in groundwaters should provide a powerful tool for characterizing the impact of the burgeoning coal bed methane industry on the hydrology of the powder river basin

generation mechanism of tropical instability waves in the equatorial pacific ocean abstracttropical instability waves tiws are prominent features in the equatorial pacific propagating westward at a speed of 0 5 m s 1 with a wavelength of 1000 km in this study we show that

precipitation melt and runoff in the northern tien shan abstract precipitation and snow distribution melt of glaciers and snow and runoff formation in two basins in the northern tien shan are calculated and described major climatic features are a spring summer precipitation maximum occurring simultaneously with ice and snow melt precipitation increases with altitude except in winter when an air temperature inversion occurs air temperature is a good predictor of glacial melt typical hydrographs have two floods one is formed from melt of seasonal snow cover and the other is formed from melt of glacial ice the second flood is usually larger than the first in mountain basins of the northern tien shan direct runoff from rainfall averages about 7 12 of annual volume the glacial runoff is 18 28 of average annual runoff in basins with area of glaciation not less than 30 40 but during summer it can increase to 40 70 of average annual runoff surface runoff from seasonal snow melt during spring and summer is 18 of average annual runoff the groundwater component is 34 38 of average annual runoff

magnetotelluric studies across the kurduwadi gravity feature abstract the deccan traps have a predominantly negative bougner anomaly with two prominent regions of gravity low along the nasik koyna and nasik kurduwadi lines on the basis of these a rift zone was suggested along the nasik kurduwadi region this rift theory was not supported by later deep seismic sounding dss studies subsequent gravity modelling studies indicated that the observed anomalies could be explained in terms of undulations in the crust mantle boundary and the conrad discontinuity it was thus felt that the region should be reinvestigated to check for the rift valley using magnetotelluric mt techniques a linear profile about 100 km long was identified for these studies magnetotelluric data were collected at 11 stations with an average station spacing of 8 15 km the data at ten of these stations were found to be good for the purpose of analysis the rotation of the impedance tensor showed a regional rotation angle of 60 east of north with this rotation the direction of the major resistivity is approximately perpendicular to the direction of gravity low as well as the west coast of the indian peninsula one dimensional 1d analysis at all stations showed a five layered structure a regional geoelectric cross section is proposed using the 1d data the influence of the west coast was studied using two dimensional 2d modelling techniques the deccan basalts were observed to be about 500 m thick overlying the granitic upper crust a mid crustal conductor with a conductance of about 200 s was delineated at a depth of 12 18 km this shows good agreement with the conrad discontinuity reported from the dss and gravity studies the moho discontinuity was not seen in the data presumably because it is not accompanied by any detectable change of electrical resistivity the lithosphere asthenosphere boundary is shallow at a depth of about 80 100 km the asthenosphere is not well formed as is evident from the large resistivities 50 100 m signature of sediments below the traps could not be found in the survey area

the nature and thickness of lithosphere beneath the archean dharwar craton southern india a magnetotelluric model abstract the dharwar craton in the southern indian shield region occupies a key position in reconstructions of the earliest supercontinent ur as well as in the global neoarchean configurations of continental assembly here we synthesize the available geophysical data that include heat flow seismic tomography temperature profile derived from xenoliths and magnetotellurics mt from the dharwar craton a thickness of more than 200 km is identified for the lithosphere beneath this craton by magnetotelluric model our inference lends support to the models from recent seismological investigations that argue for the presence of a thick lithosphere as well as the upper mantle structure derived from the analysis of mantle xenoliths a synthesis of recent geophysical and geochemical data together with our magnetotelluric model indicate the existence of a thick lithospheric root beneath the dharwar craton and suggest that not much of the lithosphere has been eroded since precambrian in this region leading to the conclusion that the dharwar craton preserves an archean tectosphere an increase in the lithospheric thickness from east to west in the dharwar craton and the lithosphere asthenosphere boundary lab migration to shallower levels observed from geophysical data towards the east is interpreted as a probable reflection of the mesoproterozoic subduction erosion of the archean cratonic keel

evolutions of water stable isotopes and the contributions of cryosphere to the alpine river on the tibetan plateau the significant changes of cryosphere on the tibetan plateau tp are an important cause of concern for the huge population in asia which depends on the glacier permafrost feed rivers up to now little is known about the response of runoff to the cryospheric changes under a warming climate taking an example of a typical alpine river hereafter named klr river in kunlun mountains pass on the tp to investigate the hydrological processes and quantify the potential recharge sources using stable isotopes and electrical conductivities the results showed significantly temporal variations in isotopes of precipitation and river water deviations in the precipitation isotopes indicated that precipitation in kunlun mountains pass during summer months mainly originated from local recycled moisture and slightly influenced by monsoon the klr river was separated into three hydrological components which include precipitation meltwater of glacier and meltwater of subsurface ground ice on average the meltwater of glacier accounted for 56 64 of total flow whereas the meltwater of subsurface ground ice contributed 37 44 and only 5 92 was supplied by precipitation evidently the contributions of glacier and thawing permafrost are up to as high as 94 the cryosphere played a crucial role on the hydrological cycle on the tp which would be important to understand the water resource distribution in permafrost regions on the tp under the global warming

ice volume estimation inferred from ice thickness and surface measurements for continental glacier wind river range wyoming usa the wind river range in wyoming usa contains the largest concentration of glacial mass in the rocky mountains of the contiguous usa despite this distinction only a few field or remotely sensed studies providing glacier volume changes have been published the current study focuses on continental glacier located on the northern end of the range and uses two field datasets high accuracy gps surface elevation points and ice penetrating radar transects of the glacier bed to create a three dimensional model of glacier volume current surface elevations are compared with historical elevation data to calculate surface elevation change over time an average thinning rate of 13 8 7 8 m 0 30 0 17 m a 1 between 1966 and 2012 was found surface elevation change rates varied across the glacier ranging from 0 30 to 0 98 m a 1 taking into account variable melt rates across the glacier along with a glacial volume of 72 1 106 10 8 106 m3 we estimate that continental glacier will be reduced in volume by 43 over the next 100 years and will disappear completely over the next 300 400 years if current climatic conditions persist

northern latitude chemical weathering rates clues from the mackenzie river basin canada abstract the main scope of this study is to investigate parameters controlling chemical weathering rates for a large river system submitted to subarctic climate more than 110 river water samples from the mackenzie river system northern canada have been sampled and analyzed for major and trace elements and sr isotopic ratios in the dissolved phase the three main morphological units are reflected in water chemistry rivers from the canadian shield are very dilute dominated by silicate weathering millot et al 2002 whereas the rivers of the rocky and mackenzie mountains as well as the rivers of the sedimentary interior platform are dominated by carbonate weathering and are so 4 rich compared to the rivers of the mackenzie and rocky mountains the rivers of the interior plains are organic silica and na rich and constitute the dominant input term to the mackenzie river mainstream rivers of the canadian shield area do not significantly contribute to the mackenzie river system using elemental ratios and sr isotopic ratios a mathematical inversion procedure is presented that distinguishes between solutes derived from silicate weathering and solutes derived from carbonate weathering carbonate weathering rates are mostly controlled by runoff which is higher in the mountainous part of the mackenzie basin these rates are comparable to the carbonate weathering rates of warmer areas of the world it is possible that part of the carbonate weathering is controlled by sulfide oxidative weathering but its extent remains difficult to assess conversely to what was stated by edmond and huh 1997 overall silicate weathering rates in the mackenzie basin are low ranging from 0 13 to 4 3 tons km 2 yr na k ca mg and confirm the negative action of temperature on silicate weathering rates for river basins in cold climates in contrast to what has been observed in other large river systems such as the amazon and ganges rivers silicate weathering rates appear 3 to 4 times more elevated in the plains than in the mountainous headwaters this contradicts the raymo hypothesis raymo and ruddiman 1992 isotopic characterization of suspended material clearly shows that the higher weathering rates reported for the plains are not due to the weathering of fine sediments produced in the mountains e g by glaciers and deposited in the plains rather the relatively high chemical denudation rates in the plains are attributed to lithology uncompacted shales high mechanical denudation and the abundance of soil organic matter derived from incomplete degradation and promoting crystal lattice degradation by element complexation the three to fourfold factor of chemical weathering enhancement between the plains and mountains is similar to the fourfold factor of enhancement found by moulton et al 2000 between unvegetated and vegetated watershed this study confirms the negative action of temperature on silicate weathering for cold climate but shows that additional factors such as organic matter associated with northern watersheds are able to counteract the effect of temperature this acceleration by a factor of 4 in the plains is equivalent to a 6 c increase in temperature

a comment on long waves in the pacific ocean abstract surface currents near the equator in the eastern pacific ocean fluctuate with periods of 21 30 days channel model experiments determined that these changes in oscillations are attributed to variations in the intensity of the south equatorial current

the isotopic record at an alpine glacier and its implications for local climatic changes and isotopic homogenization processes stratigraphic variations of oxygen isotopes in the snow which accumulates during the winter at the norwegian glacier austre okstindbreen are not entirely eliminated after 1 2 months of ablation in the following summer the relationship between regional temperature changes and 18 o values in the snowpack is affected by many natural factors but 1989 90 winter air temperatures were reflected in the snow which remained on austre okstindbreen at 1350 m a s l in july 1990 there were many variations of 18 o values in the 4 1 m of snow above the 1989 summer surface but variations in the underlying firn were relatively small meltwater percolation modifies the initial variations of 18 o values in the snowpack at a site below the mean equilibrium line altitude on austre okstindbreen increased isotopic homogenization within a 10 day period in july accompanied an increase of the mean 18 o value although the isotopic record at a temperate glacier is likely to be influenced by more factors than is that at polar glaciers it can provide an estimate of the approximate trend of local temperature variations

ecosystem controlled soil rock pco2 and carbonate weathering constraints by temperature and soil water content carbonate dissolution in soil groundwater systems depends dominantly on ph temperature and the saturation state of the solution with respect to abundant minerals the ph of the solution is in general controlled by partial pressure of co2 pco 2 produced by ecosystem respiration which is controlled by temperature and water availability in order to better understand the control of land temperature on carbonate weathering a database of published spring water hydrogeochemistry was built and analysed assuming that spring water is in equilibrium with the soil water rock atmosphere the soil pco 2 can be back calculated based on a database of spring water chemistry the average soil rock co2 was calculated by an inverse model framework and a strong relationship with temperature was observed the identified relationship suggests a temperature control on carbonate weathering as a result of variations in soil rock pco 2 which is itself controlled by ecosystem respiration processes the findings are relevant for global scale analysis of carbonate weathering and carbon fluxes to the ocean because concentration of weathering products from the soil rock system into the river system in humid high temperature regions are suggested to be larger than in low temperature regions furthermore results suggest that in specific spring samples the hydrochemical evolution of rain water percolating through the soil rock complex can best be described by an open system with pco 2 controlled by the ecosystem abundance of evaporites and pyrite sources influence significantly the chemistry of spring water and corrections must be taken into account in order to implement the inverse model framework presented in this study annual surface temperature and soil water content were identified as suitable variables to develop the parameterization of soil rock pco 2 mechanistically consistent with soil respiration rate findings

electrical structure of the crust below the deccan flood basalts india inferred from magnetotelluric soundings summary the indian shield has experienced major stable continental region scr earthquakes in the recent past which occurred in the deccan volcanic province until now the deeper crust below the deccan traps where thick basaltic layers cover large areas of the indian shield remains poorly understood a magnetotelluric mt study covering a broad period range was conducted along a n s running profile of 330 km length to achieve more insights into the nature of the crustal electrical structure below the flood basalts after dimensionality analysis and decomposition 2 d inversions for te and tm modes were carried out the basalt cover characterized by at first glance surprisingly low electrical resistivities is found to have an average thickness of 400 m with the exception of central parts of the profile where it reaches up to 700 m the crust is in general highly resistive but several subvertical zones of enhanced conductivity were delineated in the middle to lower crust which are tentatively explained as images of hidden partly reactivated faults fractures of the precambrian basement sensitivity analysis indicates a high resolution of these features an alternative approach incorporating macro anisotropy is additionally considered and corresponding 2 d anisotropic forward modelling confirms the existence of successions of conductive dykes in the deep crust

water geochemistry of the xijiang basin rivers south china chemical weathering and co2 consumption abstract the xijiang river the mainstream of the zhujiang pearl river which is the second largest river in china in terms of discharge flows through a large carbonate rock region in south china the chemical and sr isotopic compositions of the xijiang waters were determined during the high flow season in order to understand the chemical weathering processes associated co2 consumption and anthropogenic influences within the carbonate dominated basin the major ion compositions of the river waters are characterized by the dominance of ca2 mg2 hco 3 and are significantly rich in so 4 2 the so 4 2 is mainly derived from the oxidation of sulfide minerals and acid precipitation caused by coal combustion chemical and sr isotopic compositions of the river waters indicate that four reservoirs carbonates silicates evaporites and anthropogenic inputs contribute to the total dissolved loads the chemical weathering rates of carbonates and silicates for the xijiang basin are estimated to be approximately 78 5 and 7 45 ton km 2 a 1 respectively the total chemical weathering rate of rocks for the xijiang basin is approximately 86 1 ton km 2 a 1 or 42 mm ka 1 which is much higher than global mean values the budgets of co2 consumption by carbonate and silicate weathering are estimated to be 284 109 and 54 3 109 mol a 1 respectively it would appear that h2so4 is involved as a proton donor in weathering reactions in the xijiang basin calculated results show that the contribution of cations from rock weathering induced by h2so4 accounts for approximately 11 2 results from this study show that the flux of co2 released into the atmosphere is approximately 0 1 106 mol c km 2 a 1 or 0 41 1012 g c a 1 produced by h2so4 induced carbonate weathering in the basin when extrapolated to the entire surface area of carbonate in sw china the flux of co2 released to the atmosphere by h2so4 induced carbonate weathering is about 1 41 1012 g c a 1

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 differing biogeochemical and microbial signatures of glaciers and rock glaciers glaciers and rock glaciers supply water and bioavailable nutrients to headwater mountain lakes and streams across all regions of the american west here we present a comparative study of the metal nutrient and microbial characteristics of glacial and rock glacial influence on headwater ecosystems in three mountain ranges of the contiguous u s the cascade mountains rocky mountains and sierra nevada several meltwater characteristics water temperature conductivity ph metals nutrients complexity of dissolved organic matter dom and bacterial richness and diversity differed significantly between glacier and rock glacier meltwaters while other characteristics ca fe sio2 concentrations reactive nitrogen and microbial processing of dom showed distinct trends between mountain ranges regardless of meltwater source some characteristics were affected both by glacier type and mountain range e g temperature ammonium nh4 and nitrate no3 concentrations and bacterial diversity due to the ubiquity of rock glaciers and the accelerating loss of the low latitude glaciers our results point to the important and changing influence that these frozen features place on headwater ecosystems

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

super mobility of hot indian lithosphere negi j g pandey o p and agrawal p k 1986 super mobility of hot indian lithosphere tectonoph vsics 131 147 156 the great mobility of the indian subcontinent during the last 180 million years 9000 km of south north motion with an anticlockwise rotation of about 60 o has long been a major puzzle for theorists of plate tectonics a relative analysis of the available heat flow data the estimated temperature depth regime of india and the gravity anomalies reveals that the indian lithosphere does not have the characteristics of a typical shield zone and that it has higher radioactivity smaller viscous drag decidedly low viscosity of 10 p lower density and a well defined low velocity zone as compared to other shield areas of the world these factors appear to contribute significantly to the faster northward movement of the thin indian lithosphere as compared to the almost immobile african plate

influence of carbonates on the riverine carbon cycle in an anthropogenically dominated catchment basin evidence from major elements and stable carbon isotopes in the lagan river n ireland abstract investigation of anthropogenic versus natural controls of the carbon cycle in the lagan river revealed a strong influence of carbonates this was evident by increasing ph values along the river as well as isotopic compositions of the riverine dissolved inorganic carbon 13cdic that approached expected values for carbonate dissolution this predominant influence of carbonates existed despite their minor abundance of only 5 in this densely populated catchment basin and outlines their capacity of buffering anthropogenic influences and co2 turnover these effects should be even more pronounced in other rivers where carbonates occupy a larger proportion of the catchment basin geology other controls on the riverine carbon cycle were silicate weathering and respiratory turnover of organic material that originated mainly from anthropogenic inputs and increased the dic pool by up to 26 6 predominant natural controls on the lagan river carbon cycle changed to anthropogenic ones closer to the mouth before discharging into belfast lough a recently installed weir caused stagnant seawater to make up between 53 and 92 of the water mass poor vertical mixing caused o2 decreases and anaerobic sedimentary activity that resulted in methane production recently installed aerators at the sediment surface did not prevent ongoing methanogenesis this was documented by decreased pco2 and more 13c enriched dic values at the sediment water interface when compared to those of surface waters from the same sampling sites installations of such weirs in estuaries of other rivers may cause similar anoxic effects that influence their biogeochemistry

controls over the strontium isotope composition of river water abstract strontium concentrations and isotope ratios have been measured in river and ground waters from the ganges orinoco and amazon river basins when compared with major element concentrations the data set has allowed a detailed examination of the controls over the strontium isotope systematics of riverine input to the oceans in the following environments 1 1 typical drainage basins containing limestones evaporites shales and alumino silicate metamorphic and igneous rocks 2 2 shield terrains containing no chemical or biogenic sediments and 3 3 the floodplains that constitute the largest areas of many large rivers the strontium concentration and isotope composition of river waters are largely defined by mixing of strontium derived from limestones and evaporites with strontium derived from silicate rocks the strontium isotope composition of the limestone endmember generally lies within the phanerozoic seawater range which buffers the 87 sr 86 sr ratios of major rivers a major exception is provided by the rivers draining the himalayas where widescale regional metamorphism appears to have led to an enrichment in limestones of radiogenic strontium derived from coexisting silicate rocks the strontium isotope systematics of rivers draining shield areas are controlled by the intense transportlimited nature of the weathering reactions and thereby limits variations in the strontium flux from these terrains floodplains are only a minor source of dissolved strontium to river waters and precipitation of soil salts in some floodplains can reduce the riverine flux of dissolved strontium to the oceans the most effective mechanisms for altering the isotope ratio and flux of riverine strontium to the oceans are increased glaciation and large scale regional metamorphism of the type produced during continental collision both mechanisms provide a means for increasing the 87 sr 86 sr ratio of the global riverine flux

the first large scale bioavailable sr isotope map of china and its implication for provenance studies abstract strontium isotope ratio 87sr 86sr has been widely used to trace human migrations across geologically distinct landscapes in archaeological and forensic sciences 87sr 86sr based provenance studies require a detailed strontium reference map to make valid interpretations of mobility patterns for a given region in this study we first review the previous development for 87sr 86sr isoscapes relevant to research on migration and then present the first map of bioavailable 87sr 86sr ratios for china based on 1935 measurements on biosphere samples collated from published research and supplemented by our targeted collection strategy the results show that 87sr 86sr ratios in china span a large range and exhibit regional patterns largely dependent on the divergent geological conditions of each of china s tectonic blocks we further combine river water 87sr 86sr ratios with lithology integrated elemental data and chemical weathering rates to determine which dominant weathering patterns e g silicate carbonate or evaporite have the most significant influence on 87sr 86sr ratios the low ranges of 87sr 86sr ratios 0 7125 appear in the cathaysia block as well as some orogenic belts and the southeastern margin of the tibetan plateau likely due to the influence of the metamorphic rocks and granitoid sources additionally topography differential weathering among lithologies and eolian deposits e g loess are also significant factors that influence 87sr 86sr ratios in china our study reveals that the large variation of 87sr 86sr ratios across china is predominately driven by geological conditions revealing that future sr isotope provenance studies can shed on ancient and historical migrations in china

lithospheric mantle deformation beneath the indian cratons abstract the nature of deformation of the deep continental roots beneath the archean early proterozoic terrains opens the question whether these ancient terrains have had stable roots since the precambrian or whether recent plate motions have deformed them in view of this we make an attempt to study the thermal structure beneath the cratonic regions of the indian shield which vary in lithospheric thickness from 65 km in the singhbhum craton to 148 km in the archean dharwars the average depth of 104 km to the top of the underlying asthenosphere is consistent with other termination methods and is in fact less than half the 200 400 km depth found in other stable areas of the earth similarly the average reduced heat flow of about 35 mw m2 and moho temperature of about 550 c range 400 730 c for the indian cratons are also much higher than their counterparts elsewhere our study indicates a large scale deformation of the cratonic mantle lithosphere beneath the indian shield since the mesoproterozoic c

environmental conditions of boreal springs explained by capture zone characteristics summary springs are unique ecosystems but in many cases they are severely threatened and there is an urgent need for better spring management and conservation to this end we studied water quality and quantity in springs in oulanka national park north east finland multivariate statistical methods were employed to relate spring water quality and quantity to hydrogeology and land use of the spring capture zone this revealed that most springs studied were affected by locally atypical dolostone limestone bedrock resulting in high calcium ph and alkalinity values using ward s hierarchical clustering the springs were grouped into four clusters based on their water chemistry one cluster consisted of springs affected by past small scale agriculture whereas other clusters were affected by the variable bedrock e g springs only 1 km from the dolostone limestone bedrock area were beyond its calcium rich impact zone according to a random forest model the best predictors of spring water chemistry were spring altitude and the stable hydrogen isotope ratio of the water 2h thus stable water isotopes could be widely applicable for boreal spring management they may also provide a rough estimate of groundwater flow route i e whether it is mainly local or regional which largely determines the chemical characteristics of spring water our approach could be applied in other boreal regions and at larger spatial scales for improved classification of springs and for better targeted spring management

chemical and isotopic characteristics of groundwater dominated radovna river nw slovenia in order to investigate stream water spring waters and water from a borehole facies weathering processes residence times and average recharge altitudes in the radovna river valley were analysed for their concentrations of dissolved ca2 mg2 k na hco3 cl no3 so4 2 and for the isotope compositions of hydrogen oxygen and dissolved inorganic carbon dic all water samples show a ca2 hco3 water facies with low contents of k na cl no3 and so4 2 water rock interaction and carbonate weathering are the significant contributors to water geochemistry analysis of the water chemistry indicates that waters drain a monolithological terrain and non anthropogenically influenced watershed the 2h and 18o values are seasonally dependent on the snowmelt precipitation and evaporation the average recharge altitudes for all sampling locations are between 1120 and 2130 m the average residence time for the stream water is 2 4 years and for karst springs 1 2 years the 13cdic values in all samples are influenced by dissolution of carbonates degradation of organic matter and by equilibrium with atmospheric co2 all geochemical and isotope analyses show changes in stream water in the downstream direction and are highly dependent on the inflow of karstic spring based on hydrogeological mapping geochemical and stable isotope results a conceptual hydrogeological model of the radovna system in which karstic and alluvial aquifers are in contact was determined

geochemistry of the dissolved load of the changjiang basin rivers anthropogenic impacts and chemical weathering abstract this study focuses on the chemical and sr isotopic compositions of the dissolved load of the rivers of the changjiang basin one of the largest riverine systems in the world water samples were collected in august 2006 from the main tributaries and the main changjiang channel the chemical and isotopic analyses indicated that four major reservoirs carbonates silicates evaporites and agriculture urban effluents contribute to the total dissolved solutes the overall chemical weathering carbonate and silicate rate for the changjiang is approximately 40 ton km2 year or 19 mm kyr similar to that of the ganges brahmaputra system and the basin is characterized by carbonate and silicate weathering rates ranging from 17 to 56 ton km2 year and from 0 7 to 7 1 ton km2 year respectively in the lower reach of the changjiang main channel the weathering rates are estimated to be 36 and 2 2 ton km2 year for carbonates and silicates respectively it appears that sulphuric acid may dominate chemical weathering reactions for some sub basins the budgets of co2 consumption are estimated to be 646 109 and 191 109 mol year by carbonate and silicate weathering respectively the contribution of the anthropogenic inputs to the cationic tds of the changjiang is estimated to be 15 20 for the most downstream stations our study suggested that the changjiang is strongly impacted by human activities and is very sensitive to the change of land use

crustal structure from deep seismic soundings along the koyna ii kelsi loni profile in the deccan trap area india abstract the crustal depth section obtained from deep seismic soundings along the koyna ii kelsi loni profile which lies near latitude 18 n roughly in the east west direction in that part of the deccan trap maharashtra state india shows a number of reflection segments below the deccan traps down to the moho discontinuity a deep fault below the deccan traps 13 km east of mahad divides the entire cross section including the moho boundary into two crustal blocks the reflection segments show updip towards the west coast in the western block the moho discontinuity which is at a depth of 39 km near the deep fault starts rising towards the coast reaching a depth of 31 5 km at the west coast the eastern block is thrown up by 1 5 km with respect to the western block along the deep fault a structural contour map of the moho discontinuity for the koyna reservoir area has been prepared from the present results and the crustal information obtained along the koyna i profile kaila et al 1979a shows that the deep fault in the koyna area is aligned in the nnw sse direction refraction seismic data analysis by the wave front method reveals that the thickness of the deccan trap increases towards the west coast the deccan trap is 600 700 m thick in the eastern region between nira sp 130 and loni sp 200 and attains a thickness of 1500 m at 10 km east of the west coast the longitudinal wave velocity in the deccan traps along the profile varies from 4 8 to 5 0 km sec and in the crystalline basement from 6 0 to 6 15 km sec a tentative isopach contour map of the deccan traps and a tentative structural contour map of the pre deccan trap contact have been prepared for the koyna reservoir area from the results along the koyna ii and koyna i profiles a flexure aligned in a nnw sse direction in the pre deccan trap contact which is an expression of the deep fault into the basement has been clearly brought out the flexure coincides in general with the orientation of the deccan volcanic scarp in this area

chemical weathering under mid to cool temperate and monsoon controlled climate a study on water geochemistry of the songhuajiang river system northeast china abstract for the first time the river water geochemistry of the songhuajiang basin the third largest river system in china has been studied in order to understand chemical weathering and associated co2 consumption rate in a mid to cool temperate and monsoon controlled climatic zone the major ion compositions of the river waters are characterized by the dominance of ca2 and hco 3 accounting for 46 and 74 of major cations and anions respectively the average total dissolved solids tds 116 mg l 1 and total cation concentration tz 1388 eq l 1 of the river waters are similar to those of global major rivers the chemical weathering rates of carbonate silicate and evaporites in the whole songhuajiang basin are estimated to be approximately 5 15 2 23 and 0 40 t km 2 a 1 respectively the total rock weathering rate for the whole songhuajiang basin is approximately 7 78 t km 2 a 1 which is at the lower end of the spectrum for global major rivers and is comparable with that of the amur and the congo zaire river the estimated co2 consumption rates for the whole songhuajiang basin are 53 4 103 mol km 2 a 1 and 66 6 103 mol km 2 a 1 by carbonate and silicate weathering respectively as a sub basin the 2nd songhuajiang has the highest 18 9 t km 2 a 1 while the nenjiang river basin has the lowest total rock weathering rate 5 03 t km 2 a 1 which indicates important controls of regional climate and lithology compared to the large rivers of china total rock weathering rates increase from north to south supporting the idea that the climate acts as major control on global chemical weathering the co2 consumption rate by silicate weathering within the whole songhuajiang river basin though under mid to cool temperate climate is in the same order of magnitude as that of huanghe 82 4 103 mol km 2 a 1 and is not much lower than that of changjiang 112 103 mol km 2 a 1 which suggests that the role of songhuajiang river weathering in long term climate change cannot be neglected compared to those of the large rivers of china

continental glacier meltwater contributions to late summer stream flow and water quality in the northern wind river range wyoming usa the wind river range in wyoming contains more than 60 glaciers that are part of the headwaters for the wind missouri green colorado and snake columbia river systems continental glacier lies on the crest of the northern wind river range and covers approximately 2 5 km2 with meltwater flowing into west torrey creek and the wind river discharge measurements of upper continental glacier meltwater were made in august 2012 and 2014 water samples were collected in 2014 for the analysis of stable isotopes field parameters and 23 trace elements this study demonstrated that continental glacier meltwater accounted for a mean of 32 91 8 4 of torrey creek flow and 4 11 18 38 of wind river flow as measured above red creek for august 2012 and 2014 scaling of these results to all perennial snow and ice in the upper torrey creek basin yielded an estimate of 82 70 contribution to torrey creek flow and 10 32 of wind river flow above red creek during august glacier meltwater contributions versus snow melt to torrey creek based on 18o ratios ranged from 81 05 to 82 70 of flow with a mean of 81 88 1 17 for august 2014 continental glacier meltwater accounted for 89 99 of nitrate nitrite and 34 83 of total phosphorus loading to torrey creek in august 2014 the ph of the snow and glacier meltwater was less than 6 0 likely the result of nitrate nitrite and other atmospheric deposition finally analysis of trace elements showed distinct differences between water sources

tropical glacier meltwater contribution to stream discharge a case study in the cordillera blanca peru original abstract discharge measurements climate observations and hydrochemical samples gathered monthly 1998 99 in the yanamarey and uruashraju glacier fed catchments of the cordillera blanca peru permit an analysis of the glacier meltwater contribution to stream flow these glacier catchments feed the rio santa which discharges into the pacific ocean based on a water balance computation glacier melt contributes an estimated 35 of the average discharge from the catchments for comparison a volumetric end member mixing model of oxygen isotopes shows glacier melt contributes 30 45 to the total annual discharge based on stream geochemistry discharge from the yanamarey glacier catchment provides 30 of the annual volume discharged from the querococha watershed which is 10 glacierized by analogy the larger rio santa watershed also 10 glacierized receives at least 12 of its annual discharge from melting glacier ice tributary watersheds to the rio santa with larger fractions of glacier cover have less variable runoff and enhanced discharge demonstrating that the glaciers effectively buffer stream discharge seasonally with continued glacier melting stream flow will likely become more variable and there will be less dry season runoff

response of dissolved inorganic carbon dic and δ13cdic to changes in climate and land cover in sw china karst catchments abstract monthly hydrochemical data and 13c of dissolved inorganic carbon dic in karst water samples from september 2007 to october 2012 were obtained to reveal the controlling mechanisms on dic geochemistry and 13cdic under different conditions of climate and land cover in three karst catchments banzhai dengzhanhe and chenqi in guizhou province sw china dic of karst water at the banzhai site comes mainly from carbonate dissolution under open system conditions with soil co2 produced by root respiration and organic carbon decomposition with lowest 13c values under its dense virgin forest coverage weaker carbonate bedrock dissolution due to sparse and thin soil cover results in lower 13cdic pco2 dic and ec and lower cation and anion concentrations at the chenqi site larger soil co2 input from a thick layer of soil results in high pco2 and dic and low ph sic and 13cdic in the karst water at the dengzhanhe site a lesser soil co2 input due to stronger karst rock desertification and strong gypsum dissolution contribute to higher 13cdic high ec and high cation and anion concentrations soil co2 inputs controlled by biological activity and available soil moisture carbonate bedrock dissolution dilution and degassing effects vary seasonally following rainfall and temperature changes consequently there are seasonal cycles in hydrochemistry and 13cdic of the karst water with high pco2 and low ph ec sic and 13cdic values in the warm and rainy seasons and vice versa during the cold and dry seasons a strongly positive shift 3 in 13cdic occurred in the drought year 2011 indicating that 13cdic in groundwater systems can be an effective indicator of environmental and or climate changes

hydrogeochemistry of alpine springs from north slovenia insights from stable isotopes abstract spring water chemistry and carbon cycling in our study mainly depend on geological composition of the aquifer the investigated alpine springs in slovenia represent waters strongly influenced by chemical weathering of mesozoic limestone and dolomite only one spring was located in permo carboniferous shales the carbon isotopic composition of dissolved inorganic carbon dic and suspended organic carbon poc as well as major solute concentrations yielded insights into the origin of carbon in alpine spring waters the major solute composition was dominated by carbonic acid dissolution of calcite waters were generally close to saturation with respect to calcite and dissolved co 2 was up to fortyfold supersaturated relative to the atmosphere 13 c of dic indicates the portion of soil co 2 contributed in water and is related with soil thickness of infiltrating water in aquifer and could be therefore used as a tool for vulnerability assessment the 13 c of dic ranged from 15 8 to 1 5 and indicated less and more vulnerable aquifers mass balances of carbon for spring waters draining carbonate rocks suggest that carbonate dissolution contributes from approximately 49 to 86 and degradation of organic matter from 13 7 to 51 4 depending on spring and its relation with rock type soil environment and geomorphic position stable oxygen isotope composition of water 18 o h2o and tritium values range from 12 2 to 9 3 and from 6 4 to 9 8 tu respectively and indicate recharge from modern precipitation according to active decay of tritium and tritium in modern precipitation the age of spring waters are estimated to be about 2 6 years for springs located in julian alps about 5 years for springs located in karavanke and about 5 years for springs located in kamnisko savinjske alps

chemical dynamics of the st lawrence riverine system δdh2o δ18oh2o δ13cdic δ34ssulfate and dissolved 87sr 86sr chemical and stable isotope analyses of the st clair detroit niagara and st lawrence rivers st lawrence system and their tributaries show that the chemical and isotopic compositions of the waters are strongly controlled by the geology of their drainage basins tributaries draining the canadian shield have very low tds hco3 so42 ca2 mg2 no3 sr2 higher si and fetotal and high 87sr 86sr ratios 0 710 0 713 the grand and thames rivers that drain paleozoic limestones dolostones and evaporites are characterized by opposite attributes the st lawrence and the tributaries draining the canadian appalachians fall between these two endmembers the st clair detroit and niagara rivers do not show any pronounced seasonal variations in major component chemistry due to buffering by the great lakes in contrast pronounced seasonal variations characterize the lower st lawrence mainly because of significant tributary inputs into the overall water budget the d and 18o in the st lawrence range from 60 9 to 44 5 and from 8 5 to 6 1 smow respectively much heavier than the comparative values measured for the tributaries 92 8 to 58 3 and 13 1 to 8 5 this is a consequence of evaporative loss that over the residence time of water of 102 years equals about 7 of the water volume in the great lakes the strontium and sulfur isotopic values for the st lawrence system are relatively uniform with measured values from 0 70927 to 0 71112 for 87sr 86sr and from 4 3 to 5 6 for sulfate 34s their seasonal variations are also minor the strontium and sulfur fluxes of the st lawrence river are calculated to be 7 84 108 and 1 09 1011 mol a respectively the relative contributions of the great lakes tributaries and other sources to these fluxes are 73 16 11 for strontium and 64 13 23 for sulfur isotopic composition of dissolved inorganic carbon 13cdic in the st lawrence system ranges from 4 7 to 0 7 considerably heavier than the values for the tributaries 16 5 to 6 7 the light 13cdic values for the tributaries suggest that co2 from bacterial respiration plays an important role in the isotopic composition of riverine dic however in the main stem river s this bacterial signal is masked by isotopic equilibration with atmospheric co2 due to the long residence time of water in the great lakes seasonally the main stem river s have heavier 13c values in the fall than in the spring a consequence of preferential 12c consumption by photosynthetic plants in the epilimnion of the great lakes during the growth season in the down stream portion of the st lawrence river influx of isotopically light tributary waters causes progressive 13c depletion from 1 3 to 2 0 and 1 4 to 3 0 in the fall and spring respectively the total dic carbon flux of the st lawrence river is calculated to be 3 9 1011 mol a mass balance calculations show that the relative contributions of the great lakes tributaries decay of organic matter exchange with the atmosphere and dissolution of carbonates to this total dic flux are 81 13 2 6 10 in the spring and 83 15 2 4 0 in the fall respectively

hydrochemistry deducing basaltic trap thickness for groundwater resource mapping along the deccan volcanic province dvp margin in india it is hypothesized that hydrochemical parameters can be employed to deduce the basaltic trap thickness and that there exist diverse hydrochemical processes within the existing host rocks along the deccan volcanic province dvp margin chemical imprints of aquifers in various flows of flood basalt and fissured zones of granites had been appraised using major ion chemistry of groundwater in a test site of 623 km2 at the southern margin of the dvp in india the wide ranging hydrochemical processes obtained from empirical data describe the predominance of carbonate dolomite calcite and anorthite weathering in basalts and alkali feldspar albite and orthoclase in granites results showed that the elevated concentrations of alkaline earth elements in basaltic aquifers and alkali rich elements in granitic aquifers were useful in tracing the sources of host rock for dissolved mineral reactants further a digital elevation model using shuttle radar topography mission 90 m elevation satellite data aided in deciphering trap thickness vertical transition zone of trap and granitic basement comprising the well depths and hydrochemistry the mapping of trap thickness is useful to explore the groundwater resources at the vertical transition zone between the basaltic trap and granitic base the estimated thickness of the basaltic trap is varied from 4 to 98 m at the dvp southern margin which is further verified with the help of exploratory well lithologs matched closely

hydrologic controls on radiogenic sr in meltwater from an alpine glacier system athabasca glacier canada abstract filtered subglacial meltwater samples were collected daily during the onset of melt may and peak melt july over the 2011 melt season at the athabasca glacier alberta canada and analyzed for strontium 87 strontium 86 87 sr 86 sr isotopic composition to infer the evolution of subglacial weathering processes both the underlying bedrock composition and subglacial water rock interaction time are the primary influences on meltwater 87 sr 86 sr the athabasca glacier is situated atop middle cambrian carbonate bedrock that also contains silicate minerals the length of time that subglacial meltwater interacts with the underlying bedrock and substrate is a predominant determining factor in solute concentration over the course of the melt season increasing trends in ca k and ca mg correspond to overall decreasing trends in 87 sr 86 sr which indicate a shift in weathering processes from the presence of silicate weathering to primarily carbonate weathering early in the melt season rates of carbonate dissolution slow as meltwater approaches saturation with respect to calcite and dolomite corresponding to an increase in silicate weathering that includes sr rich silicate minerals and an increase in meltwater 87 sr 86 sr however carbonate minerals are preferentially weathered in unsaturated waters during the warmest part of a melt season the discharged meltwater is under saturated causing an increase in carbonate weathering and a decrease in the radiogenic sr signal likewise larger fraction contributions of meltwater from glacial ice corresponds to lower 87 sr 86 sr values as the meltwater has lower water rock interaction times in the subglacial system these results indicate that although weathering of sr containing silicate minerals occurs in carbonate dominated glaciated terrains the continual contribution of new meltwater permits the carbonate weathering signal to dominate

an isotopic and geochemical study of snowmelt runoff in a small arctic watershed old water contributions to snowmelt runoff in a stream can be defined as water which was stored in the catchment prior to the start of the runoff event in question we used mass balance techniques for natural oxygen 18 and several chemical parameters electrical conductivity ca and mg to estimate the magnitude and timing of old water contributions to snowmelt runoff in the apex river watershed during the 1983 field season the apex river catchment is located in the southern part of baffin island northwest territories canada the watershed has an area of 60 km2 it is in the zone of continuous permafrost and the geology is dominantly precambrian gneiss with sporadic thin glacial overburden the isotopic data indicate that for the snowmelt season of 1983 third highest peak discharge of 11 years of record approximately 50 per cent of the peak stream discharge consisted of old water our data also suggest that about 60 per cent of the entire 1983 hydrograph was old water the chemical parameters give old water contributions which are at least 10 per cent less than the isotopically derived estimate but they are consistent with the isotopic estimate during peak flow

mass loss on himalayan glacier endangers water resources 1 ice cores drilled from glaciers around the world generally contain horizons with elevated levels of beta radioactivity including 36 cl and 3 h associated with atmospheric thermonuclear bomb testing in the 1950s and 1960s ice cores collected in 2006 from naimona nyi glacier in the himalaya tibet lack these distinctive marker horizons suggesting no net accumulation of mass ice since at least 1950 naimona nyi is the highest glacier 6050 masl documented to be losing mass annually suggesting the possibility of similar mass loss on other high elevation glaciers in low and mid latitudes under a warmer earth scenario if climatic conditions dominating the mass balance of naimona nyi extend to other glaciers in the region the implications for water resources could be serious as these glaciers feed the headwaters of the indus ganges and brahmaputra rivers that sustain one of the world s most populous regions

regional geoelectric structure beneath deccan volcanic province of the indian subcontinent using magnetotellurics understanding deep continental structure and the seismotectonics of deccan trap covered region has attained greater importance in recent years for imaging the deep crustal structure magnetotelluric mt investigations have been carried out along three long profiles viz guhagarh sangole gs sangole partur sp edlabad khandwa ek and one short profile along nanasi mokhad nm the results of gs sp and nm profiles show that the traps lie directly over high resistive basement with thin inter trappean sediments where large thickness of sediments of the order of 1 5 2 0 km has been delineated along ek profile across narmada son lineament zone the basement is intersected by faults fractures which are clearly delineated as narrow steep conducting features at a few locations the conducting features delineated along sp profile are also seen from the results of aeromagnetic anomalies towards the southern part of the profile these features are spatially correlated with kurduwadi rift proposed earlier from gravity studies apart from the kurduwadi rift extending to deep crustal levels the present study indicates additional conductive features in the basement the variation in the resistivity along gs profile can be attributed to crustal block structure in koyna region similar block structure is also seen along nm profile deccan trap thickness based on various geophysical methods varies gradually from 1 8 km towards west to 0 3 km towards the east while this is the general trend a sharp variation in the thickness of trap is observed near koyna the resistivity of the trap is more 150 200 m towards the west as compared to the east 50 60 m indicating more compact or denser nature for the basalt towards west the upper crust is highly resistive 5000 10 000 m and the lower crust is moderately resistive 500 1000 m in the present study seismotectonics of the region is discussed based on the regional geoelectrical structure with lateral variation in the resistivity of the basement and presence of anomalous conductors in the crust 2007 elsevier b v all rights reserved

co2 outgassing and calcite precipitation in falling spring creek virginia u s a abstract chemical and physical observations are presented to explain the evolution of stream water chemistry along the flow path in warm river cave and falling spring creek mixing of two chemically and thermally distinct waters in the cave defines the initial stream water chemistry all along the flow path the observed composition is influenced by outgassing of co2 the water is supersaturated with respect to co2 both in the subsurface and at the surface of the earth but outgassing is greatest in turbulent stretches of the stream above and at the waterfalls the loss of co2 drives the solution to high degrees of supersaturation with respect to calcite physical evidence for calcite precipitation exists in the rimstone dams observed inside the cave and in the travertine deposits above and below the falls along falling spring creek travertine precipitation in the streambed consumes ca2 and hco 3 with most of the precipitation occurring where the stream experiences the most rapid co2 loss the stream water maintains a significant level of supersaturation with respect to calcite over the entire length of the flow path studied

contribution of glacier meltwater to streamflow in the wind river range wyoming inferred via a bayesian mixing model applied to isotopic measurements the wind river range wrr of wyoming has the largest concentration of alpine glaciers in the american rockies and contributes to several major river systems in the western united states declines in the areal extent and volume of these glaciers are well documented and eventual loss of alpine glaciers will reduce the amount of water available for agricultural and domestic use the contribution of glacial melt to streamflow remains largely unquantified in wyoming we used isotope measurements and bayesian modeling to estimate the fractional contribution of glacier meltwater to dinwoody creek dc in the wrr on bi weekly and seasonal spring summer and fall time scales over 2 years in 2007 and 2008 we made temporally intensive measurements of the stable isotope composition of water from the dc watershed samples of the primary sources of streamflow snowmelt glacier melt rain and baseflow were collected during field campaigns and automated collection of stream samples occurred over the melt season isotope data d and 18o were analyzed within a hierarchical bayesian framework that incorporated temporal and spatial correlations glacial melt contributed a significant proportion 53 59 to streamflow in a low flow year 2007 or when streamflow was low during a high flow year 2008 in 2008 a large and persistent snowpack contributed significantly 0 42 51 to streamflow in mid summer the large contribution of glacial melt to streamflow suggests that the loss of glaciers may impact riparian ecosystems and human water supplies in the late summer and in years with low snowpack copyright 2011 john wiley sons ltd

chemical weathering in the upper reaches of xijiang river draining the yunnan guizhou plateau southwest china abstract chemical and strontium isotopic compositions of nanpanjiang river and beipanjiang river in the upper reaches of xijiang river draining the yunnan guizhou plateau southwest china were measured with a main purpose to understand the rock weathering and associated co 2 consumption rates in the karstic landform dominated area the chemical ion composition of the river water is characterized by dominance of ca 2 mg 2 and hco 3 and so 4 2 which account for more than 90 of total ion concentration 87 sr 86 sr ratios of nanpanjiang river water range between 0 7080 and 0 7140 while those of most beipanjiang river water vary within a limited range from 0 7075 to 0 7085 weathering of carbonate rocks dominate chemistry of major ions especially in the water of beipanjiang river whereas weathering of silicate minerals in the upper reaches of nanpanjiang river basin is obvious in addition to carbonate weathering mainly according to the sr isotopic composition of the river water analyses of the stoichiometry of the river water show that the water chemistry is controlled by carbonate dissolution not only by carbonic but also by sulfuric acid and indicate that sulfuric acid plays an important role in carbonate weathering the sulfate in river water is mainly from atmospheric input by coal combustion industries and from oxidation of sulfide minerals during weathering of coal containing strata and coal mining in the catchment the chemical weathering rates of silicate and carbonate and associated co 2 consumption rates by both carbonic and sulfuric acid and by only carbonic acid are respectively estimated the results show that chemical weathering rates of carbonate and silicate weathering in beipanjiang river basin are higher than those of nanpanjiang river basin showing linkages of geology and geography in the catchment to crustal weathering the involvement of sulfuric acid in carbonate weathering greatly enhances the carbonate weathering but lowers the co 2 consumption rates indicating that sulfide acid is an important agent to rock weathering and the role of sulfide acid should further be clarified in view of the regional and global budget of co 2

isotopic and geochemical identification of main groundwater supply sources to an alluvial aquifer the allier river valley france summary hydrodynamic hydrochemical and isotopic investigations were carried out on 18 points including boreholes piezometers and surface waters from february 2011 to august 2012 to assess groundwater quality in the unconfined shallow alluvial aquifer of the allier river one of the main tributary of the loire river the study area located near the city of clermont ferrand france plays an important socio economic role as the alluvial aquifer is the major source of drinking water for about 100 000 inhabitants the objective of the project aims at understanding the functioning of alluvial aquifers that occupy a pre eminent position in the hydrogeologic landscape both for their economic role production of drinking water and agricultural development and for their ecological role moreover this study also targets at determining the factors and processes controlling shallow groundwater quality and origin the water circulates from the south with a natural alimentation from the hills in the non pumped part of the alluvial aquifer in the pumping zone this general behaviour is altered by the pumping that makes the water from the allier river enter the system in a large proportion four end members have been identified for the recharge of the alluvial groundwater rainfall allier river surrounding hills aquifer and the southern non pumped part of the alluvial system results indicate that despite the global ca hco 3 water type of the groundwater spatial variations of physico chemical parameters do exist in the study area ionic concentrations increase from the allier river towards east due either to the increase in the residence time or a mixing with groundwater coming from the aquifer s borders stable isotopes of the water molecule show the same results boreholes close to the river bank are recharged by the allier river depleted values while boreholes far from the river exhibit isotopic contents close to the values of hills spring or to the southern part of the alluvial aquifer both recharged by local precipitation one borehole b65 does not follow this scheme of functioning and presents values attesting of a probable sealing of the allier river banks based on these results the contribution of each end member has been calculated and the functioning of the alluvial system determined

horizontal reynolds stresses in the central equatorial pacific seven 13 month long current records from the north pacific experiment hawaii to tahiti shuttle experiment during 1979 1980 were analyzed to investigate eddy energetics of the upper ocean within 75 km of the equator profiling current meter data from the experiment were also used in an attempt to relate the eddy motions to the mean zonal flow the current fluctuations are highly anisotropic with zonal current dominating after removal of a linear trend plus annual and semiannual harmonics the residual high frequency current fluctuations are much more nearly isotropic the high frequency eddy kinetic energy decreases by a factor of 2 over the upper 250 m and at 100 m has a relative minimum on the equator the seasonal time scale eddy kinetic energy shows a much more dramatic decrease below the thermocline with the exception of tidal peaks the spectra of zonal current are red while meridional current spectra show a flattening at the lowest resolvable frequencies meridional current was non stationary with an energetic packet of 10 to 15 day period oscillations occurring in early 1980 the off diagonal component of the reynolds stress tensor u calculated from the high frequency residuals is everywhere positive decreasing from north to south and with depth the implied cross equatorial flux of zonal momentum is at odds with eddy viscosity parameterizations which relate u to the mean meridional shear of the zonal current the observed distribution of reynolds stresses might be explained by radiation of energy from an instability of the portion of the south equatorial current north of the equator in all cases the high frequency u time series are significantly skewed toward positive values and show no evidence of periodicity indicating that the process es responsible is are intermittent and broadband this is consistent with the instability mechanism

temporal dynamics of suspended sediment transport in a glacierized andean basin abstract suspended sediment transport can affect water quality and aquatic ecosystems and its quantification is of the highest importance for river and watershed management suspended sediment concentration ssc and discharge were measured at two locations in the estero morales a chilean andean stream draining a small basin 27 km2 hosting glacierized areas of about 1 8 km2 approximately half of the suspended sediment yield 470 t year 1 km 2 was transported during the snowmelt period and half during glacier melting the hysteresis patterns between discharge and ssc were calculated for each daily hydrograph and were analysed to shed light on the location and activity of different sediment sources at the basin scale during snowmelt an unlimited supply of fine sediments is provided in the lower and middle part of the basin and hysteresis patterns tend to be clockwise as the peaks in ssc precede the peak of discharge in daily hydrographs instead during glacier melting the source of fine sediments is the proglacial area producing counterclockwise hysteresis it is suggested that the analysis of hysteretic patterns over time provides a simple concept for interpreting variability of location and activity of sediment sources at the basin scale

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

assessment of land subsidence mechanisms triggered by dolomitic marble dissolution from hydrogeochemistry and stable isotopes of spring waters abstract this study presents geochemical results of springs draining a small humid tropical watershed composed of geologically dolomitic marbles in central sri lanka water samples were investigated for their major ion chemistry water stable isotope composition 2 h h2o and 18 o h2o and isotope composition of dissolved inorganic carbon 13 c dic from major ion chemistry ca 2 and mg 2 were the dominant cations and were balanced mostly by hco 3 all collected spring water samples scattered around the local meteoric water line with values from 31 9 to 46 8 for 2 h h2o and from 5 5 to 7 4 for 18 o h2o against vsmow this indicates local groundwater recharge pathways by regional precipitation rather than water from deeper aquifer systems concentrations of dissolved inorganic carbon dic ranged from 0 91 to 9 38 mm l 1 and 13 c dic ranged from 22 to 14 against vpdb with an average of 16 samples of spring water from carbonate rocks had increased dic and 13 c dic together with elevated ph values combined 13 c dic and ca 2 and mg 2 contents suggest that groundwater evolution was dominated by dissolution of dolomitic marble this unexpected weathering process was favored by intense rain and high ambient temperatures and excessive co 2 production in tropical soils the intense weathering resulted in karst structures with high hydraulic conductivities that rendered the terrain tectonically less stable

on the electrical crust mantle structure in fennoscandia no moho and the asthenosphere revealed summary an interpretation of the geomagnetic inductive response function c 0 observed at kiruna in northern sweden is herein undertaken the bounds of acceptable solutions are initially discovered by a monte carlo random search procedure and the best fitting solutions are examined by the application of linear theory to the problem the data are shown to have a higher degree of internal consistency than that described by the estimated variances of each datum a further monte carlo inversion of the variance reduced data set gives solutions with well defined model parameters the two major features of the models are 1 a small or non existent electrical conductivity variation across the seismic moho boundary and 2 the unequivocal existence of an electrical asthenosphere under the fenno scandian shield beginning at a depth of between 155 185 km and of 60km minimum thickness both of these observations have seismic counterparts finally possible mantle temperature profiles are deduced which depend on the assumptions and laboratory data employed

hydrological modeling in the karst area rižana spring catchment slovenia karst aquifers are known for their heterogeneity and irregular complex flow patterns which make them more difficult to model and demand specific modeling approaches this paper presents one such approach which is based on a conceptual model the model was applied in a karst area of the catchment of ri ana spring 200 km it is based on the mike she code and incorporates the main hydrological processes and geological features of the karst aquifer diffuse and concentrated infiltration allogenic recharge quick and slow groundwater flow shifting groundwater divides and groundwater outflow from the catchment area modeling of evapotranspiration and flow in the upper part of the unsaturated zone is more detailed for the modeling of groundwater flow in the karst aquifer a conceptual model was applied which uses drainage function for the simulation of groundwater flow through large conduits karst channels and large fissures the model was calibrated and validated against the observed ri ana spring discharge which represents a measured response of the aquifer the results of validation show that the model is able to adequately simulate temporal evolution of the spring discharge measured by nash sutcliffe coefficient 0 82 as well as overall water balance

geochemical isotopic and hydrological mass balance approaches to constrain the lake water groundwater interaction in dal lake kashmir valley it is important to have qualitative as well as quantitative understanding of the hydraulic exchange between lake and groundwater for effective water resource management dal a famous urban fresh water lake plays a fundamental role in social cultural and economic dynamics of the kashmir valley in this paper geochemical isotopic and hydrological mass balance approaches are used to constrain the lake water groundwater interaction of dal lake and to identify the sources of lake water water samples of precipitation n 27 lake water n 18 and groundwater n 32 were collected across the lake and its catchment for the analysis of 18o and 2h a total of 444 lake water samples and 440 groundwater samples springs tube wells and dug wells were collected for the analysis of ca2 mg2 hco3 so4 2 cl no3 na and k water table and lake water level were monitored at 40 observation locations in the catchment water table map including ph and ec values corroborate and verify the gaining nature of the dal lake stable isotopes of lake water in boddal and gagribal basins showed more deviation from the global meteoric water line than hazratbal and nigeen basins indicating the evaporation of lake water the isotopic and geochemical mass balance suggested that groundwater contributes a significant proportion 23 40 to dal lake the estimated average groundwater contribution to dal lake ranged from 31 2 103 to 674 103 m3 day 1 with an average of 276 103 m3 day 1 the study will be useful to delineate the possible sources of nutrients and pollutants entering the lake and for the management of lake water resources for sustainable development

characteristics of stable isotope and hydrochemistry of the groundwater around qinghai lake ne qinghai tibet plateau china the integrated use of isotopic and hydrochemical tracers is an effective approach for investigating complex hydrological processes of groundwater the stable isotope composition and hydrochemistry of the groundwater around qinghai lake were investigated to study the sources and recharge areas most of the groundwater points lie close to the local meteoric water line indicating that the ground waters were recharged primarily from precipitation in the basin though it had undergone varying degrees of evaporation the hydrochemical analysis showed that the groundwater was mainly freshwater and that the hydrochemical type was ca mg hco3 the results of the boomerang envelope model and solutes calculated indicated that the groundwater chemistry was mainly controlled by carbonate dissolution around qinghai lake the recharge altitudes of groundwater were relatively low at 3 400 m a s l on the northern shore of qinghai lake locations g1 and g5 relatively high above 3 900 m a s l on the southern shore locations g3 and g4 and approximately 3 700 m a s l on the western shore location g2 furthermore groundwater samples from the fault zone e g g3 would be recharged in part from fissure or inter basin water high salinity of groundwater on the western shore location g2 was related with the evaporite dissolution the groundwater is unsuitable for drinking and the drinking water should be improved and enhanced in this area knowledge of our research can promote effective management of water resources in this cold and semiarid region and add new data to global groundwater database

hydrochemistry and isotope composition of springs in the tecopa basin southeastern california usa abstract springs and seeps in the tecopa basin were sampled and analyzed for their major ion chemistry and oxygen hydrogen and boron isotope compositions in order to assess the possible origins of the waters the tecopa basin is a groundwater discharge area along the amargosa river drainage basin south of the nevada test site and proposed high level nuclear waste repository at yucca mountain nv the spring waters are categorized into three end member hydrochemical facies 1 ph neutral na ca mg so4 hco3 water with moderate to high total dissolved solids 2 mildly alkaline na cl so4 hco3 water with high total dissolved solids and 3 alkaline na hco3 co3 water with high total dissolved solids the temperatures of most of the springs range from 17 c to 32 c however waters in the tecopa hot spring area range from 9 c to 47 c the oxygen and hydrogen isotope compositions normalized to smow of the waters are as follows the facies 1 springs have a mean 18o of 12 77 0 14 1 and d of 94 9 0 5 1 the facies 2 springs have a mean 18o of 12 73 0 19 1 and d of 97 7 0 9 1 the facies 3 spring has a mean 18o of 13 09 0 17 1 and d of 103 5 0 7 1 the mean boron concentrations and isotope compositions range from 2 4 mg l and 11b of 2 5 for facies 1 springs to 72 8 mg l and 11b of 3 8 for the facies 3 spring the facies 1 waters have chemical and isotope compositions consistent with meteoric recharge in the spring mountains nv groundwater flow through the regional carbonate aquifer and minor mixing with more concentrated water the thermal facies 2 waters are isotopically and chemically distinct from waters in the regional basin fill and carbonate aquifer systems these waters are interpreted to originate from fractured water bearing strata beneath the regional carbonate aquifer that discharge only in the southernmost part of the great basin the facies 3 spring is isotopically and chemically similar to basin fill aquifer waters in the amargosa desert but has higher sodium alkalinity and boron contents due to interaction with saline alkaline lake deposits of the plio pleistocene lake tecopa beds geologic geochemical and isotope data suggest that these three distinct water types flow through hydrogeologic compartments in the tecopa basin the compartments are interpreted to have been created by the impermeable lake tecopa beds and geologic structures within the basin

the geodynamic context of the latur india earthquake 30 september 1993 abstract in the past 30 years six disastrous earthquakes have occurred in the indian shield these earthquakes were believed to be associated either with reservoir induced seismicity or with well known geological features in spite of these earthquakes the indian shield was considered to be a stable shield the latur earthquake of 30 september 1993 29 september 1993 umt was far from any geological features of reservoir that might explain its presence the present analysis of recent seismicity in the indian continent shows that the latur earthquake is consistent with release of stress accumulated by interaction of the indian plate with the asian continent the observed seismicity in the indian shield appears to draw its energy from continuing interaction between the two plates and it might be triggered by subsurface hydrological fluctuations