estimation of deep reservoir temperature of co2 rich springs in kangwon district south korea abstract weakly acid to neutral co 2 rich springs ph 5 5 to 6 7 with high concentrations of dissolved ions tds 419 to 3091 mg l and bicarbonate 249 to 2470 mg l occur in kangwon district south korea they are grouped into three chemical types na hco 3 ca na hco 3 and ca hco 3 the na hco 3 type waters correspond to mature or partially equilibrated waters while the other two types show the hydrochemical characteristics of immature waters in this study we examined the applicability of chemical geothermometers and multiple mineral equilibrium approach to estimate potential deep reservoir temperatures the application of silica na k and na k ca thermometers to a representative na hco 3 type water yielded a reasonable temperature estimate 115 157 c for a deep geothermal reservoir the multiple mineral equilibrium approach yielded a similar temperature estimate about 140 160 c on the other hand the ca hco 3 type waters showed a relatively low and wide range of temperature estimates about 60 130 c which suggests that their disequilibrium state is possibly due to surface water mixing we believe that deep reservoir temperatures of co 2 rich groundwaters in kangwon district can be estimated from the chemistry of na hco 3 type waters and possibly approach 140 160 c

environmental isotopes meet 3d geological modelling conceptualising recharge and structurally controlled aquifer connectivity in the basalt plains of south western victoria australia summary to develop a conceptual model of recharge and inter aquifer connectivity for a complex aquifer system in southwestern victoria australia a three dimensional 3d geological model was constructed and used to examine the influence of the regional geology on groundwater composition and age as well as recharge mechanisms the major aquifers are three basalts differentiated on age and geomorphological features and an underlying palaeovalley deep lead system the upper fine grained sediments of the deep lead form an aquitard that separates the basalt from the permeable sands and gravels beneath recharge calculations chloride mass balance and water table fluctuation methods salinity stable isotope tritium and radiocarbon data show that volcanoes and the youngest basalts although volumetrically minor form preferential recharge areas for all the basalts up to 30 mm year and also recharge the deep lead sediments through volcanic necks that penetrate the aquitard infiltration through the thick clay rich soils on the older basalts is small typically 1 2 mm year and saline resulting in a progressive increase of groundwater salinity along the flow path in these basalts the comparison of fault location with groundwater age in the deep lead aquifer suggests that in some areas faults exert significant structural control on groundwater flow this study demonstrates the value of integrating geological hydrogeological and hydrochemical data to identify preferential recharge areas inter aquifer connectivity and the influence of faults on groundwater flow in a complex aquifer system

isotopic identification of co2 from a deep origin in thermomineral waters of southeastern spain abstract the overexploitation of the alto guadalentin detrital aquifer has led to an unusually high gas content in the waters which is released as the hydrostatic charge decreases the predominant gas proved to be co 2 isotopic studies show that 18 o values are in the range 8 8 to 6 5 smow d ranges between 45 and 40 smow excess deuterium lies between 8 0 and 27 4 and 13 c values lie between 8 1 and 3 8 pdb this reveals that there is an enrichment in 18 o as well as mixing processes between meteoric and deep circulating waters tectonic and seismotectonic studies indicate crustal thinning in the studied region and numerous normal reverse and strike slip faults marked by positive thermal anomalies there is also evidence of present day tectonic activity

tracing the migration of mantle co2 in gas fields and mineral water springs in south east australia using noble gas and stable isotopes abstract geochemical monitoring of co2 storage requires understanding of both innate and introduced fluids in the crust as well as the subsurface processes that can change the geochemical fingerprint of co2 during injection storage and any subsequent migration here we analyse a natural analogue of co2 storage migration and leakage to the atmosphere using noble gas and stable isotopes to constrain the effect of these processes on the geochemical fingerprint of the co2 we present the most comprehensive evidence to date for mantle sourced co2 in south east australia including well gas and co2 rich mineral spring samples from the otway basin and central victorian highlands cvh 3he 4he ratios in well gases and co2 springs range from 1 21 to 3 07 ra and 1 23 3 65 rc ra respectively we present chemical fractionation models to explain the observed range of 3he 4he ratios he ne ar kr xe concentrations and 13c co2 values in the springs and the well gases the variability of 3he 4he in the well gases is controlled by the gas residence time in the reservoir and associated radiogenic 4he accumulation 3he 4he in co2 springs decrease away from the main mantle fluid supply conduit we identify one main pathway for co2 supply to the surface in the cvh located near a major fault zone solubility fractionation during phase separation is proposed to explain the range in noble gas concentrations and 13c co2 values measured in the mineral spring samples this process is also responsible for low 3he concentrations and associated high co2 3he which are commonly interpreted as evidence for mixing with crustal co2 the elevated co2 3he can be explained solely by solubility fractionation without the need to invoke other co2 sources the noble gases in the springs and well gases can be traced back to a single end member which has suffered varying degrees of radiogenic helium accumulation and late stage degassing this work shows that combined stable and noble gas isotopes in natural gases provide a robust tool for identifying the migration of injected co2 to the shallow subsurface

marsis remote sounding of localized density structures in the dayside martian ionosphere a study of controlling parameters enhanced topside electron densities in the dayside martian ionosphere have been repetitively observed in areas of near radial crustal magnetic fields for periods of tens of days indicating their long term spatial and temporal stability despite changing solar wind conditions we perform a statistical study of these density structures using the ionospheric mode of the mars advanced radar for subsurface and ionosphere sounding marsis onboard mars express we estimate the apparent extents of these structures relative to the altitude of the surrounding ionosphere the apex of the density structures often lies higher than the surrounding ionosphere median vertical extent of 18 km which indicates upwellings these structures are much wider than they are high with latitudinal scales of several degrees the radar reflector regions are observed above both moderate and strong magnetic anomalies and their precise locations and latitudinal extents match quite well with the locations and latitudinal extents of magnetic structures of given magnetic polarity oblique to vertical fields which happen to be regions where the field lines are open part of the time the majority of the density structures occur in regions where ionospheric plasma is dominant indicating closed field regions shielded from shocked solar wind plasma

hydroclimatic and geothermal controls on the salinity of mbaka lakes sw tanzania limnological and paleolimnological implications summary the hydroclimatic and geothermal controls on the salinity of small tropical crater lakes masoko katubwi kyambangunguru ilamba and kingiri aligned with the mbaka fault line north of lake malawi are investigated by water stable isotopes which are used to trace evaporative processes as to establish lake water balances and by chloride concentrations allowing to identify the main salinity sources this region shows positive excess in the exchanges between atmosphere and lake surfaces p e 0 with the exception of lake ilamba the lakes are closed surface basins and their levels are relatively stable as catchment inflows cannot be neglected groundwater outflows have to compensate for this excess the isotopic budgets show that these lakes constitute a series of windows on the local shallow aquifer in addition the estimated losses by evaporation cannot solely account for the lake salinity observed as the most saline lake differs from not the most evaporated lake salinity is then investigated from chloride concentrations and seems to be controlled by inflows which results from the mixing between i fresh and ii hydrothermal ground waters the contrasts in lake salinity almost one order of magnitude are first related to the hydrothermal contribution which increases with the proximity of the mbaka fault second due to positive exchange with the atmosphere the lake salinity appears systematically diluted in regard to the respective inflows this dilution effect increases as the fraction of total inputs lost by evaporation or the lake water residence time increases this current hydrological study shows that local wetter conditions are not inconsistent with higher lake salinity and allows to conciliate the questioned and apparent contradictory lake masoko wetter and salty paleoenvironmental and paleoclimatic records for the last glacial maximum and younger dryas time intervals further in a general manner this work addresses the case of lake submitted to wet environment and highlights the potential contribution of hydrothermal water on lakes salinization occurring in active regions such as the east african rift system

formation of patterned ground and sublimation till over miocene glacier ice in beacon valley southern victoria land antarctica a thin glacial diamicton informally termed granite drift occupies the floor of central beacon valley in southern victoria land antarctica this drift is 40 ar 39 ar analyses of presumed in situ ash fall deposits that occur within granite drift at odds with the great age of this ice are high centered polygons that cut granite drift if polygon development has reworked and retransported ash fall deposits then they are untenable as chronostratigraphic markers and cannot be used to place a minimum age on the underlying glacier ice our results show that the surface of granite drift is stable at polygon centers and that enclosed ash fall deposits can be used to define the age of underlying glacier ice in our model for patterned ground development active regions lie only above polygon troughs where enhanced sublimation of underlying ice outlines high centered polygons the rate of sublimation is influenced by the development of porous gravel and cobble lag deposits that form above thermal contraction cracks in the underlying ice a negative feedback associated with the development of secondary ice lenses at the base of polygon troughs prevents runaway ice loss secondary ice lenses contrast markedly with glacial ice by lying on a d versus 18 o slope of 5 rather than a precipitation slope of 8 and by possessing a strongly negative deuterium excess the latter indicates that secondary ice lenses likely formed by melting downward percolation and subsequent refreezing of snow trapped preferentially in deep polygon troughs the internal stratigraphy of granite drift is related to the formation of surface polygons and surrounding troughs the drift is composed of two facies a nonweathered matrix supported diamicton that contains 25 striated clasts in the 16 mm fraction and a weathered clast supported diamicton with varnished and wind faceted gravels and cobbles the weathered facies is a coarse grained lag of granite drift that occurs at the base of polygon troughs and in lenses within the nonweathered facies the concentration of cosmogenic 3 he in dolerite cobbles from two profiles through the nonweathered drift facies exhibits steadily decreasing values and shows the drift to have formed by sublimation of underlying ice these profile patterns and the 3 he surface exposure ages of 1 18 0 08 ma and 0 18 0 01 ma atop these profiles indicate that churning of clasts by cryoturbation has not occurred at these sites in at least the past 10 5 and 10 6 yr although granite drift is stable at polygon centers low frequency slump events occur at the margin of active polygons slumping together with weathering of surface clasts creates the large range of cosmogenic nuclide surface exposure ages observed for granite drift maximum rates of sublimation near active thermal contraction cracks calculated by using the two 3 he depth profiles range from 5 m m y to 90 m m y sublimation rates are likely highest immediately following major slump events and decrease thereafter to values well below our maximum estimates nevertheless these rates are orders of magnitude lower than those computed on theoretical grounds during eruptions of the nearby mcmurdo group volcanic centers ash fall debris collects at the surface of granite drift either in open thermal contraction cracks or in deep troughs that lie above contraction cracks these deposits subsequently lower passively as the underlying glacier ice sublimes the fact that some regions of granite drift have escaped modification by patterned ground for at least 8 1 ma indicates long term geomorphic stability of individual polygons once established polygon toughs likely persist for as long as 10 5 10 6 yr our model of patterned ground formation which applies to the hyperarid cold desert polar climate of antarctica may also apply to similar sized polygons on mars that occur over buried ice in utopia planitia

steep transient density gradients in the martian ionosphere similar to the ionopause at venus 1 with the mars advanced radar for subsurface and ionospheric sounding marsis on the mars express mex spacecraft the electron density can be measured by two methods from the excitation of local plasma oscillations and from remote sounding a study of the local electron density versus time for 1664 orbits revealed that in 132 orbits very sharp gradients in the electron density occurred that are similar to the ionopause boundary commonly observed at venus in 40 of these cases remote sounding data have also confirmed identical locations of steep ionopause like density gradients measurements from the analyzer of space plasma and energetic atoms aspera 3 electron spectrometer and ion mass analyzer instruments also on mars express verify that these sharp decreases in the electron density occur somewhere between the end of the region where ionospheric photoelectrons are dominant and the magnetosheath combined studies of the two experiments reveal that the steep density gradients define a boundary where the magnetic fields change from open to closed this study shows that although the individual cases are from a wide range of altitudes the average altitude of the boundary as a function of solar zenith angle is almost constant the average altitude is approximately 500 km up to solar zenith angles of 60 after which it shows a slight increase the average thickness of the boundary is about 22 km according to remote sounding measurements the altitude of the steep gradients shows an increase at locations with strong crustal magnetic fields

fluid geochemistry and geothermometry in the unexploited geothermal field of the vicano cimino volcanic district central italy abstract the vicano cimino volcanic district vcvd is related to the post orogenic magmatic activity of the peri tyrrhenian sector of central italy the chemical and isotopic compositions of 333 water discharges and 25 gas emissions indicate the occurrence of two main sources 1 cold ca hco 3 to ca na k hco 3 type waters from relatively shallow aquifers hosted in volcanic and sedimentary formations and 2 thermal ca so 4 hco 3 type waters located in a deep co 2 pressurized reservoir hosted in carbonate evaporite rocks and separated from the shallow aquifers by thick sequences of low permeability formations carbon dioxide is mainly produced by thermal metamorphic decarbonation within the deepest and hottest parts of the carbonate evaporite reservoir 13 c co 2 from 3 1 to 2 2 vs vpdb likely affected by a mantle rooted co 2 release of co 2 rich gases from the deep aquifer into the overlying shallow aquifers produces high co 2 springs and bubbling pools the spatial distribution of thermal waters and co 2 rich cold discharges is strongly controlled by fractures and faults located in correspondence with buried structural highs stable isotopes d and 18 o suggest that meteoric water feeds both the shallow and deep reservoirs the relatively low r r a values 0 27 1 19 indicate that he is mainly deriving from a crustal source with minor component from the mantle affected by crustal contamination related to the subduction of the adriatic plate consistently relatively high n 2 ar and n 2 3 he ratios and positive 15 n n 2 values from 0 91 to 5 7 vs air characterize the vcvd gas discharges suggesting the occurrence of a significant excess nitrogen isotopic compositions of ch 4 13 c ch 4 and d ch 4 values from 28 9 to 22 1 vs vpdb and from 176 to 138 vs vsmow respectively and composition of light alkanes are indicative of prevalent thermogenic ch 4 although the occurrence of abiogenic ch 4 production cannot be excluded the 34 s h 2 s values from 9 3 to 11 4 vs vcdt are consistent with the hypothesis of h 2 s production from thermogenic reduction of triassic anhydrites gas geothermometry in the h 2 o h 2 ar h 2 s system suggests that the vcvd gases equilibrated in a liquid phase at redox conditions controlled by interactions of fluids with the local mineral assemblage at temperatures lower 2000 m geothermal wells this confirms that secondary processes i e steam condensation gas dissolution in shallow aquifers re equilibration at lower temperature and microbial activity significantly affect the chemistry of the uprising fluids thermal water chemistry supports the occurrence in this area of an anomalous heat flow that coupled with the recent demographic growth makes this site suitable for direct and indirect exploitation of the geothermal resource in agreement with the preliminary surveys carried out in the 1970 s 1990 s for geothermal exploration purposes

preservation of miocene glacier ice in east antarctica antarctic climate during the pliocene has been the subject of considerable debate one view holds that during part of the pliocene east antarctica was largely free of glacier ice and that vegetation survived on the coastal mountains1a 4 an alternative viewpoint argues for the development of a stable polar ice sheet by the middle miocene which has persisted since then5a 10 here we report the discovery of buried glacier ice in beacon valley east antarctica which appears to have survived for at least 8 1 million years we have dated the ice by 40ar 39ar analysis of volcanic ash in the thin overlying glacial till which we argue has undergone little if any reworking isotope and crystal fabric analyses of the ice show that it was derived from an ice sheet we suggest that stable polar conditions must have persisted in this region for at least 8 1 million years for this ice to have avoided sublimation

observations of the latitude dependence of the location of the martian magnetic pileup boundary 1 we report observations that show the dependence of the altitude of the magnetic pileup boundary mpb at mars on planetary latitude as seen by the mars global surveyor magnetometer electron reflectometer instrument the mpb is further away from mars on average at southern latitudes than at northern latitudes the data are consistent with a mpb distance mapped to the terminator plane that does not vary with latitude in the northern hemisphere but increases with increasing southern latitude in the southern hemisphere we also report increased variability in the mpb distance within the longitude range 90 270 e longitude in the southern hemisphere which is the region that contains the strongest crustal magnetic fields these trends are most obvious in a planet fixed coordinate system indicating a planet fixed driver of the mpb location the proposed mechanism is the local diversion of shocked solar wind flow by crustal magnetic fields

fluid geochemistry of natural manifestations from the southern poroto rungwe hydrothermal system tanzania preliminary conceptual model abstract the south poroto rungwe geothermal field in the northern part of the malawi rift tanzania divides in two main areas the relatively high altitude northern area around the main ngozi rungwe tukuyu and kyejo volcanoes is characterised by cold and gas rich springs in contrast hot springs occur in the southern and low altitude area between the kyela and livingstone faults the isotopic signature of the almost stagnant cold springs of the northern district is clearly influenced by h2o co2 g exchange as evidenced from negative oxygen shifts in the order of few deltas permil in contrast the isotopic signature of waters discharged from the hot springs of the southern district is markedly less affected by the h2o co2 g interaction this evidence is interpreted as an effect of the large permanent outflow of these springs which supports the hypothesis of a regional scale recharge of the major thermal springs measurements of carbon isotope variations of the dissolved inorganic carbon of waters and co2 g from the northern and southern springs support a model of co2 g driven reactivity all over the investigated area our combined chemical and isotopic results show that the composition of hot springs is consistent with a mixing between i cold surface fresh sfw and ii deep hot mineralised dhmw water indicating that the deep originated fluids also supply most of the aqueous species dissolved in the surface waters used as local potable water based on geothermometric approaches the temperature of the deep hydrothermal system has been estimated to be higher than 110 c up to 185 c in agreement with the geological and thermal setting of the malawi rift basin geochemical data point to i a major upflow zone of geothermal fluids mixed with shallow meteoric waters in the southern part of the province and ii gas absorption phenomena in the small perched aquifers of the northern volcanic highlands

radio occultation measurements of forced atmospheric waves on mars mars global surveyor performed a series of radio occultation experiments in december 1998 resulting in 36 profiles of the neutral atmosphere in late northern spring ls 74 1 77 3 the measurements are confined in latitude 64 6 67 2 n and local time 0321 0418 but their distribution in longitude is fairly uniform we used least squares spectral analysis to characterize the zonal structure of the atmosphere and constructed longitude height cross sections of both temperature and geopotential zonal variations of temperature exceed 12 k near the surface but are much smaller 2 3 k at higher altitudes zonal variations of geopotential are 200 m throughout the vertical range of the measurements these patterns of temperature and geopotential appear to be stationary relative to the surface with little day to day variation within the 7 sol span of the measurements we relied heavily on mars general circulation models gcms for guidance in understanding these data stationary planetary waves are responsible for some aspects of the temperature and geopotential fields particularly at pressures exceeding 100 200 pa on the basis of strong similarities between a gcm simulation and the observations we conclude that the disturbance takes the form of a planetary wave train excited by alba patera the data also include the signature of non sun synchronous thermal tides which produce a pattern that appears to be stationary when sampled at fixed local time comparison between a gcm simulation and the measured geopotential field provides evidence for the presence of the resonantly enhanced diurnal wave 1 kelvin mode

isotopic geochemistry of the saratoga springs implications for the origin of solutes and source of carbon dioxide we report the results of an isotopic study designed to determine the source of solutes and carbon dioxide in the famed saratoga springs new york mineral waters these waters have thousands of milligrams per liter total dissolved solid concentrations and are highly charged with carbon dioxide gas the spring waters are cold 12 c and there is no local deep seated thermal anomaly they emerge through thick shale caprock along the surface expression of normal faults the 13c 5 8 to 0 8 vienna peedee belemnite of the dissolved inorganic carbon and elevated 3he 4he ratios suggest that the source of the co2 is the mantle or an ancient deep crystallized igneous melt the stable isotopic content of the spring waters defines a mixing line between modern local meteoric waters 70 and a component with heavier d but similar 18o values this trend and that of 87sr 86sr of dissolved strontium versus 1 sr are consistent with the hypothesis that canadian shield type brines contribute salinity to the springs these brines plausibly migrate from the adirondack mountains to the topographically low mcgregor fault system in the hudson river lowlands where the saratoga springs discharge

mars ionopause a matter of pressures this study assesses under what circumstances the martian ionopause is formed on the dayside both in regions where there are strong crustal magnetic fields and areas where these fields are small 30 nt multiple data sets from three maven dayside deep dip campaigns are utilized between periapsis and 600 1 000 km as well as solar wind observations from mars express the ionopause is identified as a sudden decrease of the electron density with increasing altitude and a simultaneous increase of the electron temperature and variability below 400 km this is a physically robust approach as the electron temperature is a key parameter in determining the structure of the ionospheric profile and therefore also a strong indicator of the ionopause location we find that 36 54 of the electron density profiles over strong weak crustal magnetic field regions had an ionopause event we also evaluate the roles of ionospheric thermal and magnetic pressures on the ionopause formation as well as the presence of solar wind particles h down to the location of the ionopause we found that the topside ionosphere is typically magnetized at mostly all altitudes the ionopause if formed occurs where the total ionospheric pressure magnetic thermal equals the upstream solar wind dynamic pressure moreover the lower edge of the ionopause coincides with the altitude where the solar wind flow stops the thermal pressure suffers a significant reduction with increasing altitude and the solar wind proton density has a prominent increase

geochemistry of ground waters from the great artesian basin australia herczeg a l torgersen t chivas a r and habermehl m a 1991 geochemistry of ground waters from the great artesian basin australia j hydrol 126 225 245 ground waters from the confined lower cretaceous jurassic aquifer of the great artesian basin australia gab are characterised by na hco 3 type waters throughout the eastern and central parts of the basin and na sq c1 type waters in the western part sodium and bicarbonate increase in concentration from the northeastern margins to the southwestern discharge areas along the regional groundwater flowlines a mass balance and equilibrium model for major dissolved species and stable carbon isotopes of dissolved inorganic carbon show that the chemical trends observed are caused by mass transfer reactions involving cation exchange of na for ca mg carbonate dissolution and reactions between na and kaolinite to form na smectite the stable carbon isotopic composition of dissolved inorganic carbon dic increases from values of about 15 o near the basin margins to 6 o in the interior of the basin an inverse relationship exists between 6 3c and dic indicating addition of enriched carbon as the ground waters move basinwards a t2c 3c mass balance indicates that the trend toward heavier 6 3c values in the interior of the basin results from bacterial reduction of carbon dioxide to produce methane rather than dissolution of and equilibration with carbonate minerals the gab aquifer system is apparently open to co which is the product of in situ anaerobic fermentation producing co 2 enriched in t3c the chemical evolution of the major dissolved species and carbon isotope distribution in the eastern and central parts of the gab can then be envisaged as an initial pco 2 up to several orders of magnitude above atmospheric level is acquired within the recharge area by plant respiration and oxidation of organic matter in the soil zone initially silicate and carbonate minerals may dissolve at least in some parts of the basin resulting in increased alkalinity higher ca and mg concentrations and a 6 3c concentration of the dic of around 12 0 processes such as cation exchange of na for ca and mg in addition to the removal of some na by reverse weathering which produces a na smectite dominate in the interior of the gab the chemistry of ground waters derived from the western recharge areas is controlled by evaporite dissolution as indicated by very high ci br ratios

determination of free co2 in emergent groundwaters using a commercial beverage carbonation meter summary dissolved co 2 in groundwater is frequently supersaturated relative to its equilibrium with atmospheric partial pressure and will degas when it is conveyed to the surface estimates of dissolved co 2 concentrations can vary widely between different hydrochemical facies because they have different sources of error e g rapid degassing low alkalinity non carbonate alkalinity we sampled 60 natural spring and mine waters using a beverage industry carbonation meter which measures dissolved co 2 based on temperature and pressure changes as the sample volume is expanded using a modified field protocol the meter was found to be highly accurate in the range 0 2 35 mm co 2 the meter provided rapid accurate and precise measurements of dissolved co 2 in natural waters for a range of hydrochemical facies dissolved co 2 concentrations measured in the field with the carbonation meter were similar to co 2 determined using the ph alkalinity approach but provided immediate results and avoided errors from alkalinity and ph determination the portability and ease of use of the carbonation meter in the field made it well suited to sampling in difficult terrain the carbonation meter has proven useful in the study of aquatic systems where co 2 degassing drives geochemical changes that result in surficial mineral precipitation and deposition such as tufa travertine and mine drainage deposits

carbon dioxide and hydrogen sulfide degassing and cryptic thermal input to brimstone basin yellowstone national park wyoming abstract brimstone basin a remote area of intense hydrothermal alteration a few km east of the yellowstone caldera is rarely studied and has long been considered to be a cold remnant of an ancient hydrothermal system a field campaign in 2008 confirmed that gas emissions from the few small vents were cold and that soil temperatures in the altered area were at background levels geochemical and isotopic evidence from gas samples 3 he 4 he 3r a 13 c co 2 3 however indicate continuing magmatic gas input to the system accumulation chamber measurements revealed a surprisingly large diffuse flux of co 2 277 t d 1 and h 2 s 0 6 t d 1 the flux of co 2 reduces the 18 o content of the overlying cold groundwater and related stream waters relative to normal meteoric waters simple isotopic modeling reveals that the co 2 likely originates from geothermal water at a temperature of 93 19 c these results and the presence of thermogenic hydrocarbons c1 c2 100 and 13 c ch 4 46 4 to 42 8 in gases require some heat source at depth and refute the assumption that this is a fossil hydrothermal system

isotopic approach of rainfall and groundwater circulation in the volcanic structure of tahiti nui french polynesia abstract a chemical and isotopic study was conducted on rainfall river and spring waters from the northern half of tahiti nui tropical oceanic island in order to constrain a conceptual model of groundwater circulation within a discontinuous volcanic structure tahiti nui comprises a main shield cut by a huge landslide to the north this major flank collapse yielded the formation of a northern depression in which rapidly grew a second shield additional volcanic activity occurred along the rims of the depression as revealed by local concentrations of dykes the island is now volcanically inactive and is strongly dissected by erosion rainfall collected during a complete hydrological year at different altitudes are characterized by seasonal and altitude gradients in 18 o some of them have a deuterium excess upto 20 likely due to inland vapour recycling over the hydrological year non evaporated precipitation defines a mean annual altitude gradient of 0 7 km the mineralization and isotopic contents in river waters vary according to the geology rivers incising the main shield have low total mineral charges and are relatively enriched in stable isotopes 18 o around 3 vs vsmow whereas rivers in the northern post collapse in fill exhibit greater electrical conductivity and lower 18 o due to the contribution of more mineralized spring water springs sampled at different elevations along the nw rim of the n landslide depression have homogeneous stable isotopic compositions corresponding to signature of elevated rainfall recharge of these springs thus occurs on a localized area upto 1500 m above their altitude of emergence dominant infiltration occurs at or above the geological discontinuity between the thick impermeable base of the second shield and the late overlying fractured volcanic flows dykes from the peripheral part of the system are poorly active in terms of infiltration and water storage but likely connect the underground circulations the huge geological discontinuity between the main shield and the post collapse edifice may also concentrate the groundwater circulation this main resurgence likely occurs at a deep level of the northern submarine slope of tahiti nui

a post pioneer venus reassessment of the martian dayside ionosphere as observed by radio occultation methods the dayside altitude profiles of the electron density obtained with the radio occultation experiments on mariners 4 6 7 and 9 and the viking 1 and 2 spacecraft are collectively reanalyzed to determine the global characteristics of the dayside ionosphere of mars these analyses concentrate on the comparison of the properties of both the electron density peaks and the topside profiles with the behavior expected for a chapman layer and that observed at venus with the pioneer venus orbiter radio occultation experiment as at venus the peak densities at mars behave much like chapman layer peaks with only slight departure from a cos dependence where is the solar zenith angle in contrast the peak heights depart from ideal chapman layer behavior at venus but not at mars because the dayside neutral atmosphere at venus depends on solar zenith angle the global dust storm during the mariner 9 main mission appears to have elevated the martian ionosphere as a whole by 20 30 km without otherwise notably altering its density profile these results generally corroborate the findings of earlier studies an examination of the solar zenith angle dependence of density levels on the topsides of profiles obtained both at mars and at venus near solar minimum provides a new perspective on the solar zenith angle variation of the scale heights of the two ionospheres the key contribution of this study is the improved picture of the solar zenith angle dependences of both the peaks and scale heights of the ionosphere of mars and their comparison with venus at solar minimum in particular this study illustrates that under the similar conditions where incident solar wind dynamic pressure exceeds peak ionospheric thermal pressure the martian dayside ionosphere peaks at higher altitudes in the flanks and has a greater scale height overall thus even magnetically unshielded martian and venusian ionospheres would present slightly different obstacles to the solar wind

stable isotope geochemistry of cold co2 bearing mineral spring waters daylesford victoria australia sources of gas and water and links with waning volcanism abstract mineral springs in the victorian central highlands australia have high co 2 contents and naturally effervesce 13 c values of co 2 gas and dissolved inorganic carbon are 10 6 to 7 0 and 5 9 to 0 1 respectively with a net 13 c of 8 to 3 the carbon in these waters was derived from a mantle source associated with local pliocene to recent basaltic newer volcanic province rocks previously reported 3 he 4 he 1 2 3 1 relative to air and high he ne ratios are also consistent with the presence of magmatic volatiles silica contents imply that the waters were never heated above 130 c and that the system is not hydrothermal the occurrence of carbonated mineral springs in a relatively small region of the newer volcanics province where volcanic activity ceased several thousands of years ago may be due to the presence of late intrusions combined with deep circulation of water through deeply weathered and fractured ordovician basement a region of low seismic velocity under the daylesford area potentially images those intrusions most spring waters have 18 o and 2 h values of 8 to 6 and 45 to 35 respectively and lie to the left of the local and global meteoric water lines the anomalously low 18 o values results from co 2 exsolution at low temperatures which strongly partitions 18 o into the gas the lack of waters lying to the right of the local meteoric water line also implies that water rock interaction at elevated temperatures did not occur the 2 h values are lower than contemporary meteoric water suggesting that the waters may have recharged under colder climate conditions several thousand years ago the local ordovician rocks are gold bearing the present spring system is cold and would not efficiently transport au however volcanic is waning and the spring systems at the time of volcanism may have been hotter and able to redistribute au

monitoring of co2 rich waters with low ph and low ec an analogue study of co2 leakage into shallow aquifers the geochemistry of co2 rich springs and wells was monitored as a natural analogue study of co2 leakage into shallow aquifers in result within the relatively small study area diluted co2 rich waters dcws concentrated cw ccw and ordinary groundwaters were observed dcws showed an exceptionally low ph mean 4 8 and low ec mean 150 s cm the low ph and ec as well as the time invariant geochemistry of dcws were probably due to continuous co2 inputs into the open system which had a short reaction time and rarely consisted of reactive minerals dcws showed the low concentrations of sio2 mean 20 4 mg l and the average tritium concentration of 3 4 tu which indicates the low co2 h2o rock interaction in addition delta 13 text c text co 2 text g in equilibrium with water was estimated using the mass balance equation and 13cdic measured in water samples the results of the stable carbon isotope analysis showed that the co2 originated from a deep seated source to the shallow dcw aquifer 80 m deep below the surface whereas the deeper ccw aquifer was affected by soil organic co2 near the surface to detect the co2 leakage from co2 storage sites the geochemistry of shallow aquifers should be monitored this study result suggests that at least ph ec dic and carbon isotopes should be monitored because the monitoring of ph is helpful in an aquifer with low buffering capacity while ec can be low despite co2 leakage and the subsequently low ph at early stages depending on the subsurface environment above all this present study indicates that understanding the characteristics of aquifer conditions is of great importance for co2 leakage detection

using groundwater geochemistry and environmental isotopes to assess the correction of 14c ages in a silicate dominated aquifer system summary the use of 14c to constrain groundwater residence times requires careful correction of 14c activities a14c and an assessment of the degree of inter aquifer mixing in groundwater of the campaspe valley in the southern murray basin australia 13c values of dissolved inorganic carbon dic range from 18 to 2 using these 13c values to correct 14c ages assuming that dissolution of or exchange with matrix calcite had occurred implies that locally 90 of the dic is derived from carbonates in turn this suggests that low salinity groundwater in the deeper confined calivil renmark formation up to 50 60 km from the basin margins in the campaspe valley has a component of modern recharge which would require that widespread leakage from the overlying shepparton formation had occurred however 87sr 86sr ratios and major ion geochemistry of groundwater imply that negligible inter aquifer mixing has occurred and that calcite dissolution is a very minor process the variable 13c values are most probably due to methanogenesis via reduction of co2 in the groundwater that results in the residual dic being enriched in 13c as methanogenesis by this mechanism has only a minor impact on a14c uncorrected 14c ages are a better estimate of groundwater residence times groundwater in the north of the campaspe valley has a residence time of 9 13 ka which agrees with ages calculated from head gradients and hydraulic conductivities calivil renmark groundwater from the adjacent pyramid hill region in an area where the aquifers contain lower hydraulic conductivity sediments is substantially older up to 20 25 ka the age of groundwater from the shepparton formation increases irregularly with depth with ages of in excess of 25 ka recorded at its base this study illustrates the need to fully understand hydrogeological processes in order to correct 14c ages especially in silicate dominated aquifers where dissolution of carbonates may not be the major process controlling 13c values

a sporadic third layer in the ionosphere of mars the daytime martian ionosphere has been observed as a two layer structure with electron densities that peak at altitudes between about 110 and 130 kilometers the mars express orbiter radio science experiment on the european mars express spacecraft observed in 10 out of 120 electron density profiles a third ionospheric layer at altitude ranges of 65 to 110 kilometers where electron densities on average peaked at 0 8 10 10 per cubic meter such a layer has been predicted to be permanent and continuous its origin has been attributed to ablation of meteors and charge exchange of magnesium and iron our observations imply that this layer is present sporadically and locally

gold bearing hot spring systems of the northern coast ranges california gold mercury mineralization in the knoxville and sulphur creek districts of the coast ranges of northern california fits the emerging hot spring classification of epithermal ore deposits quartz and chalcedony veins which show hydrofracture texture are capped by subaerial sinter deposits all the deposits appear to be very young the mclaughlin deposit and the sulphur valley and elgin deposits contain hydrocarbons in their ore gold bearing quartz of the san quentin ore shoot of the mclaughlin deposit is isotopically heavy delta 18 o 24 ppm and appears to have formed near 150 degrees c from isotopically heavy waters such waters are presumed to have moved both hydrocarbons and precious metals to the surface sinter of the deposit hot springs composed of isotopically heavy fluids issue today from the centers of the sulphur valley and elgin deposits the hot spring fluids carry small concentrations of hydrocarbons and transport gold silver and mercury to the surface ag au weight ratios of the precipitates formed by the hot springs are about 1 8 gold grades of the hot spring precipitates range from 0 5 to more than 10 ppm the mean value for 20 samples is 3 3 ppm measurements show that the waters carry 1 ppb gold in solution thermodynamic calculations indicate the gold is probably present as a bisulfide complex the chemical and isotopic characteristics of the hot spring fluids appear to be similar to the fluids inferred to have formed the mclaughlin deposit in these two gold districts nonmeteoric waters are responsible for the formation of epithermal gold deposits a sedimentary or metasedimentary source for the ore forming fluids is indicated by chemical and isotopic data and is consistent with the local geology

fluid geochemistry and geothermometry in the western sector of the sabatini volcanic district and the tolfa mountains central italy abstract a geochemical survey of 197 fluid discharges cold and thermal waters and bubbling pools and 15 gas emissions from the western sector of the sabatini volcanic district and the tolfa mountains latium central italy was carried out in 2007 2008 the chemical and isotopic compositions of the fluid discharges indicate the occurrence of two main sources 1 relatively shallow aquifers with ca na k hco 3 and ca mg hco 3 compositions when trapped in volcanic and sedimentary formations respectively and 2 a deep reservoir which is hosted in the mesozoic carbonate sequence rich in co 2 and having a ca so 4 hco 3 composition dissolution of a co 2 rich gas phase into the shallow aquifers produces high tds and high pco 2 cold waters while oxidation of deep derived h 2 s to so 4 2 generates low ph the 13 c co 2 values for gas emissions from 2 8 to 2 7 vs vpdb suggest that the origin of co 2 associated with the deep fluids is mainly related to thermo metamorphic reactions within the carbonate reservoir although significant mantle contribution may also occur however r r a values 0 37 0 62 indicate that he is mainly produced by a crustal source with a minor component from a crust contaminated mantle on the basis of the 13 c ch 4 and d ch 4 values from 25 7 to 19 5 vs vpdb and from 152 to 93 4 vs vsmow respectively ch 4 production is associated with thermogenic processes possibly related to abiogenic co 2 reduction within the carbonate reservoir the 34 s h 2 s values from 9 3 to 10 4 vs vcdt are consistent with the hypothesis of a sedimentary source of sulfur from thermogenic reduction of triassic sulfates geothermometric evaluations based on chemical equilibria co 2 ch 4 and separately h 2 s suggest that the reservoir equilibrium temperature is up to 300 c the d and 18 o data indicate that water recharging both the shallow and deep aquifers has a meteoric origin fluid geochemistry coupled with gravimetric data and tectonic lineaments supports the idea that significant contributions from a deep seated geothermal brine are present in the stigliano thermal fluid discharges exploration surveys investigated this area during 70 s 90 s for geothermal purposes nevertheless presently the area is still under exploited the presence of thermal waters and anomalous heat flow together with the demographic growth of the last years makes this site a suitable location for direct applications of the geothermal resource

stable isotopic and molecular composition of desorbed coal seam gases from the walloon subgroup eastern surat basin australia this study used compositional and stable isotopic analysis to test hypotheses on the distribution and origins of walloon subgroup coal seam gas csg in the eastern surat basin queensland australia the middle jurassic walloon subgroup play differs from many other low rank csg plays particularly in methane carbon isotopic signature i e the csg is not as microbial as could be expected the carbon isotope compositions of desorbed methane from three cored appraisal wells fall within the generally accepted range for thermogenic or mixed gas 13c 58 5 to 45 3 the 13c ch4 values from stratigraphically placed coal core samples increased became more thermogenic from the top of the upper juandah coal measures to the base of the tangalooma sandstone below the tangalooma sandstone in the lower taroom coal measures the 13c ch4 values decreased with increasing depth these positively parabolic 13c profiles tracked total measured gas content in two out of the three wells studied the third well displayed lower variance of 13c ch4 and gas content increased uniformly with depth a genetic classification based on methane stable carbon isotopes alone might interpret this pattern as a transition from microbially to thermogenically sourced methane in the central coal seams however a 13c co2 profile for one well tracks total gas content and 13c ch4 and exhibits an inverse relationship with d ch4 these results together with the mostly dry nature of the gas samples c1 c2 c3 ratios up to 10 000 and relatively uniform d ch4 values d 238 to 202 suggest that microbial co2 reduction is the primary source of walloon subgroup methane as such stratigraphic variations in gas content mainly reflect the extent of microbial methanogenesis we suggest that peak microbial utilisation of h2 co2 occurred at the tangalooma sandstone level enriching the residual co2 pool and derived methane in 13c carbon 13c co2 ch4 and deuterium isotopic differences d h2o ch4 and cross plots of d h2o and 18o h2o are also consistent with kinetic isotope fractionation during microbial mediated carbonate reduction the results are relevant for applying microbially enhanced coal bed methane mecom in the surat basin

control of the topside martian ionosphere by crustal magnetic fields we present observations from the mars advanced radar for subsurface and ionospheric sounding marsis instrument onboard mars express of the thermal electron plasma density of the martian ionosphere and investigate the extent to which it is influenced by the presence of mars s remnant crustal magnetic fields we use locally measured electron densities derived when marsis is operating in active ionospheric sounding ais mode covering an altitude range from 300 km to 1200 km we compare these measured densities to an empirical model of the dayside ionospheric plasma density in this diffusive transport dominated regime we show that small spatial scale departures from the averaged values are strongly correlated with the pattern of the crustal fields persistently elevated densities are seen in regions of relatively stronger crustal fields across the whole altitude range comparing these results with measurements of the scalar magnetic field also obtained by marsis ais we characterize the dayside strength of the draped magnetic fields in the same regions finally we provide a revised empirical model of the plasma density in the martian ionosphere including parameterizations for both the crustal field dominated and draping dominated regimes

liquid carbon dioxide of magmatic origin and its role in volcanic eruptions natural liquid carbon dioxide is produced commercially from a 2 5 km deep well near the 4 500 yr old maar volcano mount gambier south australia the carbon dioxide has accumulated in a dome that is located on the extension of a linear chain of volcanic activity a magmatic origin for the fluid is suggested by the geological setting 13cpdb of 4 0 for the co2 where pdb represents the carbon isotope standard and a relatively high 3he component of the contained helium and high 3he c ratio 6 4 x 10 10 the 3he 4he and he ne ratios are 3 0 and 1 370 times those of air respectively the co2 as collected at the earth s surface at 29 5 c and 75 bar expands more than 300 fold to form a gas at 1 atm and 22 c we suggest that liquid co2 or high density co2 fluid the critical point is 31 1 c 73 9 bar of volcanic origin that expands explosively from shallow levels in the earth s crust may be a major contributor to phreatic volcanic eruptions and maar formation less violent release of magmatic co2 into crater lakes may cause gas bursts with equally disastrous consequences such as occurred at lake nyos cameroon in august 1986

character and kinematics of faults within the turbidite dominated lachlan orogen implications for tectonic evolution of eastern australia reply fault zones within turbidite dominated orogenic systems typified by the lachlan orogen of eastern australia are characterised by higher than average strain and intense mica fabrics transposition foliation and isoclinal folds poly deformation with overprinting crenulation cleavages and steeply to moderately plunging meso and micro folds they have a different character compared to the brittle ductile fault zones of classic foreland fold and thrust belts such as the appalachians and the canadian rocky mountains multiple cleavages and transposition layering record a progressive shear related deformation history an intense mica fabric evolves initially during shortening of the overlying sedimentary wedge but is progressively modified during rotation and emplacement to higher structural levels along the steep parts of inferred listric faults the deformed wedge outside the fault zones generally undergoes one phase of deformation shown by a weak to moderately developed slaty cleavage which is parallel to the axial surface of upright subhorizontally plunging chevron folds other faults within the turbidites of the lachlan orogen include the steep zones of ductile strike slip deformation that bound a centrally located high t low p metamorphic complex characterised by s c mylonites these ductile shear zones indicate a southward passage of the metamorphic complex as a crustal wedge with emplacement to higher structural levels along a leading edge ductile thrust fault ar ar dating constrains the timing of regional deformation to be mostly late ordovician through silurian across the lachlan orogen faults in the low grade turbidite sequences record the kinematic evolution of the developing lachlan orogen and indicate progressive deformation associated with simultaneous eastward propagating and migrating deformation fronts in both the western and eastern parts of the fold belt these deformation fronts are related to accretionary style deformation at the leading edges of overriding plates in an inferred southwest pacific type subduction setting from the late ordovician to the mid devonian along the former gondwana margin the fault zones effectively accommodate and preserve movements within the structurally thickening migrating and prograding accretionary wedge

chemical and stable isotopic models for boundary creek warm springs southwestern yellowstone national park wyoming abstract thermal springs of the boundary creek hydrothermal system in the southwestern part of yellowstone park outside the caldera boundary vary in chemical and isotopic composition and temperature the diversity may be accounted for by a combination of processes including boiling of a deep thermal water mixing of the deep thermal water with cool meteoric water and or with condensed steam or steam heated meteoric water and chemical reactions with surrounding rocks dissolved silica na k and ca 2 contents of the thermal springs could result from a thermal fluid with a temperature of 200 20 c chloride enthalpy and silica enthalpy mixing models suggest mixing of 230 c 220 mg l cl thermal water with cool low cl components a 350 to 390 c component with cl 300 mg l is possibly present in thermal springs inside the caldera but is not required to fit observed spring chemical and isotopic compositions irreversible mass transfer models in which a low temperature water reacts with volcanic glass as it percolates downward and warms can account for observed ph and dissolved silica k na ca 2 and mg 2 concentrations but produces insufficient cl or f for measured concentrations in the warm springs the ratio of a na a h and cl are best accounted for in mixing models the water rock interaction model fits compositions of acid sulfate waters observed at summit lake and of low cl waters involved in mixing the cold waters collected from southwestern yellowstone park have d values ranging from 118 to 145 per mil and 18 o values of 15 9 to 19 4 per mil two samples from nearby island park have d values of 112 and 114 per mil and 18 o values of 15 1 and 15 3 per mil all samples of thermal water plot significantly to the right of the meteoric water line the low cl and variable d values of the thermal waters indicate isotopic compositions are derived by extensive dilution with cold meteoric water and by steam separation on ascent to the surface many of the hot springs with higher d values may contain in addition a significant amount of high d low cl acid sulfate or steam heated meteoric water mixing models cl content and isotopic compositions of thermal springs suggest that 30 or less of a deep thermal component is present for example the highest temperature springs from three rivers silver scarf and upper boundary creek thermal areas contain up to 70 cool meteoric water and 30 hot water components springs at summit lake and middle boundary creek spring 57 are acid sulfate or steam heated meteoric water springs 27 and 48 from middle boundary creek and 49 from mountain ash contain in excess of 50 acid sulfate water and three rivers spring 46 and phillips could result from mixing hot water with 55 cool meteoric water followed by mixing of acid sulfate water extensive dilution by cool meteoric water increases the uncertainties in quantity and nature of the deep meteoric thermal component

relationship of dayside main layer ionosphere height to local solar time on mars and implications for solar wind interaction influence to understand the influence of solar wind on the daytime main layer ionosphere of mars we investigated the local solar time lst variations of three characteristic heights of the ionosphere namely the heights of the 1 mhz and 1 5 mhz reflection points i e 1 24 1010 m 3 and 2 79 1010 m 3 isodensity contours respectively and the density peak we used a total of 19 996 mars advanced radar for subsurface and ionosphere sounding observations distributed on the northern hemisphere with solar zenith angle 80 acquired from june 2005 to october 2013 we exploited the kernel partial least squares regression method to extract the nonlinear relationships of the heights to lst and a few other variables the average height of the 1 mhz reflection point decreased from 218 km at 10 00 a m to 206 km at 16 00 p m local time the height of the 1 5 mhz reflection point decreased simultaneously from 190 km to 181 km these decreasing trends are in contrast to the lst variation of the density peak height which increased from 128 km to 137 km over the same lst interval based on these findings and previous results we suggest that the solar wind may penetrate the martian ionosphere down to altitudes of about 50 km above the main density peak and may in conjunction with the asymmetric draping of the interplanetary magnetic field compress the upper part of the main ionosphere layer on the p m side 10 km more than on the a m side

radar soundings of the ionosphere of mars we report the first radar soundings of the ionosphere of mars with the marsis mars advanced radar for subsurface and ionosphere sounding instrument on board the orbiting mars express spacecraft several types of ionospheric echoes are observed ranging from vertical echoes caused by specular reflection from the horizontally stratified ionosphere to a wide variety of oblique and diffuse echoes the oblique echoes are believed to arise mainly from ionospheric structures associated with the complex crustal magnetic fields of mars echoes at the electron plasma frequency and the cyclotron period also provide measurements of the local electron density and magnetic field strength

controls on chemistry during fracture hosted flow of cold co2 bearing mineral waters daylesford victoria australia implications for resource protection abstract mineral springs from daylesford australia discharge at ambient temperatures have high co2 contents and effervesce naturally mineral waters have high hco3 and na concentrations up to 4110 and 750 mg l respectively and co2 concentrations of 620 2520 mg l calcium and mg concentrations are 61 250 and 44 215 mg l respectively and si sr ba and li are the most abundant minor and trace elements the high pco2 of these waters promotes mineral dissolution while maintaining low ph values and geochemical modelling indicates that the co2 rich mineral water must have interacted with both sediments and basalts amorphous silica concentrations and silica geothermometry indicate that these waters are unlikely to have been heated above ambient temperatures and therefore reflect shallow circulation on the order of several hundreds of metres variations in minor and trace element composition from closely adjacent spring discharges indicate that groundwater flows within relatively isolated fracture networks the chemical consistency of individual spring discharges over at least 20 a indicates that flow within these fracture networks has remained isolated over long periods the mineral water resource is at risk from mixing with potentially contaminated surface water and shallow groundwater in the discharge areas increased 2h values and cl concentrations and lower na concentrations indicate those springs that are most at risk from surface contamination and overpumping elevated no3 concentrations in a few springs indicate that these springs have already been contaminated during discharge

koci drill for drilling in ice sand and rock drill requirements design performance difficulties a new man portable drill designed to perform in ice with entrained sand and rock has been built designated the koci drill it was first used on rock covered glaciers in the mcmurdo dry valleys antarctica during the 2006 07 field season this drill is designed to be disassembled into component parts no heavier than 30 kg not including the generator for stability the drill platform weight can be augmented with available rock the field performance of the drill was generally good and both ice and rock were successfully penetrated and acceptable quality ice cores up to 1 m long were collected during the 2007 08 season the maximum depth achieved was 10 25 m given a concentrated effort at one or two sites per season a depth of 40 m is achievable problems encountered in the field will be addressed in the next generation design

magnetically controlled structures in the ionosphere of mars 1 the ionospheric sounding data obtained by the marsis mars advanced radar for subsurface and ionospheric sounding instrument on the mars express spacecraft show that the dayside ionosphere has considerable structure over regions of strong crustal magnetic fields this structure is typically seen as a hyperbola shaped trace in a display of echo intensity versus apparent altitude and time the hyperbola shapes are consistent with oblique reflections from regions of enhanced electron density that are fixed with respect to mars comparisons with the cain et al 2003 model for the crustal magnetic field of mars show that the apexes of the hyperbolas which identify the closest approach to the regions of enhanced electron density usually coincide with regions where the crustal magnetic field is strong and nearly vertical the electron density enhancements which extend as much as 50 km above the surrounding ionosphere are believed to arise from increases in the scale height of the ionosphere possibly due to heating of the ionosphere by solar wind electrons that reach the base of the ionosphere along the nearly vertical open magnetic field lines statistical analyses of the apparent altitudes of the apexes of the hyperbolas as well as analyses of repeated passes over the same region indicate that the electron density enhancements usually consist of horizontal cylinder like structures rather than isolated hemispherical structures in many cases the axes of the cylindrical density structures are aligned with the symmetry axes of adjacent cylindrical magnetic field structures with opposite polarity

cold based debris covered glaciers evaluating their potential as climate archives through studies of ground penetrating radar and surface morphology we describe the morphology and internal structure of mullins and friedman glaciers two cold based debris covered alpine glaciers that occur in neighboring valleys in the mcmurdo dry valleys antarctica both glaciers are overlain by a single dry supraglacial debris layer 8 75 cm thick each mantling debris layer is marked with near identical patterns of arcuate ridges and steps as well as corresponding changes in bulk grain size meter scale surface topography and thermal contraction crack polygons results from 24 km of ground penetrating radar data show that the ice within the uppermost 1 2 km of mullins and friedman glaciers is essentially free of englacial debris 1 by volume but thereafter is interspersed with bands of englacial debris each 3 m thick and dipping up glacier that intersect the ice surface at all major surface ridges and steps the similarity in number and pattern of englacial debris bands and corresponding surface ridges and steps across both glaciers along with model results and observations that call for negligible basal entrainment is best explained by episodic environmental change at valley headwalls our working hypothesis is that layers of englacial debris originate as supraglacial lags that form in ice accumulation areas during times of reduced net ice accumulation following renewed net ice accumulation these lags are subsequently buried by snow and ice flow englacially and intersect the ice surface to impart distinctive changes in the texture of supraglacial debris and topographic relief the implication is that the englacial structure and surface morphology of these cold based debris covered glaciers preserves a consistent record of climate and environmental change

magnetic field and plasma observations at mars initial results of the mars global surveyor mission the magnetometer and electron reflectometer investigation mag er on the mars global surveyor spacecraft has obtained magnetic field and plasma observations throughout the near mars environment from beyond the influence of mars to just above the surface at an altitude of 100 kilometers the solar wind interaction with mars is in many ways similar to that at venus and at an active comet that is primarily an ionospheric atmospheric interaction no significant planetary magnetic field of global scale has been detected to date 2 1021 gauss cubic centimeter but here the discovery of multiple magnetic anomalies of small spatial scale in the crust of mars is reported

isotopic and chemical composition of water and steam discharges from volcanic magmatic hydrothermal systems of the guanacaste geothermal province costa rica the guanacaste geothermal province encompasses three major geothermal systems each centered on its respective volcanic structure rincon de la vieja to the nw miravalles in the center and tenorioto the se each shows corresponding sets of surface manifestations vapor discharges from fumaroles and steam heated pools at altitudes 500 m lower temperature so4cl springs on the lower slopes of the respective volcano and cooler neutral cl springs to the s of the volcanic chain at altitudes 500 m the production of hco3 rich waters is limited to a narrow belt stretching to the s of miravalles volcano chemical and isotopic evidence suggests that the neutral cl waters also discharged from deep wells are derived from a more primitive clso4 water formed by transfer of readily mobilised originally magmatic constituents to deeply circulating groundwater isotopic evidence suggests that this groundwater is derived largely from areas to the north of the volcanic chain the presence of immature waters within drillable depth is indicated by the incursion of an acid so4 water into a well at miravalles after deepening to 2000 m as the cl waters rise they start to boil the separated vapors feed the fumaroles and steam heated features at the surface the residual water travels underground to be discharged some 5 25 km to the s the uniformity in chemical and isotopic compositions of the neutral cl waters is compatible with the assumption that the individual thermal systems are linked at depth to form large contiguous geothermal reservoirs beneath the guanacaste geothermal province

degassing regime of hekla volcano 2012 2013 hekla is a frequently active volcano with an infamously short pre eruptive warning period our project contributes to the ongoing work on improving hekla s monitoring and early warning systems in 2012 we began monitoring gas release at hekla the dataset comprises semi permanent near real time measurements with a multigas system quantification of diffuse gas flux and direct samples analysed for composition and isotopes 13c d and 18o in addition we used reaction path modelling to derive information on the origin and reaction pathways of the gas emissions hekla s quiescent gas composition was co2 dominated 0 8 mol fraction and the 13c signature was consistent with published values for icelandic magmas the gas is poor in h2o and s compared to hydrothermal manifestations and syn eruptive emissions from other active volcanic systems in iceland the total co2 flux from hekla central volcano diffuse soil emissions is at least 44 t d 1 thereof 14 t d 1 are sourced from a small area at the volcano s summit there was no detectable gas flux at other craters even though some of them had higher ground temperatures and had erupted more recently our measurements are consistent with a magma reservoir at depth coupled with a shallow dike beneath the summit in the current quiescent state the composition of the exsolved gas is substantially modified along its pathway to the surface through cooling and interaction with wall rock and groundwater the modification involves both significant h2o condensation and scrubbing of s bearing species leading to a co2 dominated gas emitted at the summit we conclude that a compositional shift towards more s and h2o rich gas compositions if measured in the future by the permanent multigas station should be viewed as sign of imminent volcanic unrest on hekla

mean recharge times and chemical modelling transfers from shallow groundwater to mineralized thermal waters at montrond les bains eastern massif central france summary a re appraisal of interactions between basinal waters and hydrothermal fluids within the silici clastic series of the intracontinental cenozoic forez basin is proposed using major element and isotope geochemistry together with thermodynamic models recharge processes and shallow sedimentary units in the forez basin were compared using major elements and isotopic data 87 sr 86 sr 18 o 2 h 13 c tritium and 14 c for waters sedimentary carbonates and hercynian basement rocks waters derived from late pleistocene to early holocene surface recharge followed by mixing and chemical evolution through percolation into deep groundwater horizons are investigated isotopic ratios and chemical speciation computed for deeper waters from 0 to 200 m depth indicate that mineralised waters were produced by initial surficial dissolution of calcite in calcareous mudstone providing its sr isotopic signature at about 200 m depth na h 3 o cation exchange with clayey sand rich levels provides additional ca na and oh contents for carbonate saturated water na h 3 o cation exchange can not contribute large na hco 3 concentrations geochemical changes such as increasing 13 c dic values observed from 200 to 500 m depth were modelled by addition of thermal water and geogenic co 2 in increasing proportions with depth 500 mbs thermodynamic calculations of mineral proportions indicate water rock interactions with primary minerals in the metamorphic basement and secondary minerals observed in the basin water temperature and its meteoric origin suggest a basin wide recharge system with water rock interaction driven by heat flow rather than through deep crustal fractures

igneous origin of co2 in ancient and recent hot spring waters and travertines from the northern argentinean andes abstract thermal travertines are an archive of co2 sources and sinks in hydrothermal systems two major regional factors control travertine precipitation water availability and co2 supply thus travertines form a valuable archive of hydrodynamic variability and sources of main contributions to dissolved inorganic carbon dic it is relevant to determine the main dic sources of thermal waters i e organic matter degradation recycled from older carbonates emission of deep seated magmatic co2 as they are key inputs to calculate the lithosphere atmosphere co2 budget the antuco travertine from the central andes represents one of such archives with a 500 ky record of accretionary periods dated as 425 320 260 and 155 ky bp related to high hydrothermal activity of hot springs it consists of two travertine units 1 a lower massive unit displaying large calcite pseudomorphs after aragonite that precipitated in proximal ponds with abundant water and 2 an upper stratified unit showing more distal facies bearing siliciclastics and manganese and iron oxides the replacement of aragonite by calcite in the lower unit was related to the decrease of water salinity in the thermal system through time in the antuco travertine dic 13c values of travertine parental waters of around 9 suggest that co2 was related to igneous processes and volcanic activity and released along deep seated faults relative water rock ratios derived from 18o values and fluid inclusion microthermometric data from travertine carbonates are consistent with an interpretation of greater water availability in the hydrothermal system during the late pleistocene than at present the different petrographic features and isotopic signatures are interpreted to reflect increased water availability during more humid periods in the altiplano which triggered precipitation of travertine bodies travertine growth took place during interglacial humid climate periods between marine isotope stages mis 3 and 9 which correspond to highstand events in large lakes of the andean altiplano results of this study illustrate that volcanic activity furnishing rather constant co2 and heat fluxes were the key controls of thermalism in the altiplane region during the quaternary whilst climatic changes humid vs arid periods in the late pleistocene controlled mineralogy facies and architecture of the travertines the combined use of 13c and 87sr 86sr signatures in carbonate precipitates has been proven to be of major relevance to evaluate the co2 sources along fault zones in this study

variability of the altitude of the martian sheath received 31 march 2005 revised 18 august 2005 accepted 25 august 2005 published 24 september 2005 1 using electron energy spectra we identify time periods when the mars global surveyor mgs spacecraft is in or above the martian magnetic pileup boundary mpb we use more than five years of data to develop a statistical picture of the location of the mpb relative to the mgs mapping altitude near 400 km we show for the first time that the mpb location is sensitive to interplanetary magnetic field imf orientation and to martian season and confirm a dependence upon solar wind pressure we confirm that crustal magnetic sources raise the altitude of the mpb and demonstrate that sheath electrons populate magnetic cusp regions in the southern hemisphere during southern summer strong crustal fields near the subsolar point raise the altitude of the mpb over the entire dayside implying that martian crustal fields modify the solar wind interaction globally citation brain d a j s halekas r lillis d l mitchell r p lin and d h crider 2005 variability of the altitude of the martian sheath geophys res lett 32 l18203

genetic characterization of natural gases natural gases can be characterized genetically using four properties c2 concentration carbon and hydrogen isotope variations in methane and carbon isotope variation in ethane three diagrams for genetic characterization of gases have been designed in which the carbon isotopic composition of methane is correlated with the other parameters in these diagrams compositional fields have been defined for primary gases biogenic thermogenic associated and thermogenic nonassociated and for gases which result from mixing of these gases these fields are strictly empirical and comprise compositional variations found in about 500 natural gases the isotopic and compositional variations in natural gases can be described in terms of 1 processes during formation of the gases such as bacterial fermentation or maturation of organic matter and 2 processes during secondary migration mixing of primary gases is an important and common process migration of gases predominantly affects the c2 concentration whereas the isotopic properties of gaseous hydrocarbons primarily remain unchanged allowing an assessment of the origin of migrated gases and properties of their source rocks the formation of gas from humic organic matter and coals is not yet clear from published data the diagrams use data from various basins and areas interstitial gases from the gulf of california are entirely of bacterial origin traces of thermogenic gases are formed only in the vicinity of dolerite sills gases in the south german molasse basin and in the vienna basin are of bacterial mixed and thermogenic origins data from the north italian po basin provide examples for genetic characterization of migrated gases

stable isotope geochemistry of coal bed and shale gas and related production waters a review coal bed and shale gas can be of thermogenic microbial or of mixed origin with the distinction made primarily on the basis of the molecular and stable isotope compositions of the gases and production waters methane ethane carbon dioxide and nitrogen are the main constituents of coal bed and shale gases with a general lack of c2 hydrocarbon species in gases produced from shallow levels and more mature coals and shales evidence for the presence of microbial gas include 13c ch4 values less than 50 covariation of the isotope compositions of gases and production water carbon and hydrogen isotope fractionations consistent with microbial processes and positive 13c values of dissolved inorganic carbon in production waters the co2 reduction pathway is distinguished from acetate methyl type fermentation by somewhat lower 13c ch4 and higher d ch4 but can also have overlapping values depending on the openness of the microbial system and the extent of substrate depletion crossplots of 13c ch4 versus 13c co2 and d ch4 versus 13c h2o may provide a better indication of the origin of the gases and the dominant metabolic pathway than the absolute carbon and hydrogen isotope compositions of methane in the majority of cases microbial coal bed and shale gases have carbon and hydrogen isotope fractionations close to those expected for co2 reduction primary thermogenic gases have 13c ch4 values greater than 50 and 13c values that systematically increase from c1 to c4 and define a relatively straight line when plotted against reciprocal carbon number although coals and disseminated organic matter in shales represent a continuum as hydrocarbon source rocks current data suggest a divergence between these two rock types at the high maturity end in deep basin shale gas reversals or rollovers in molecular and isotopic compositions are increasingly reported in what is effectively a closed shale system as opposed to the relative openness in coal measure environments detailed geochemical studies of coal bed and shale gas and related production waters are essential to determine not only gas origins but also the dominant methanogenic pathway in the case of microbial gases

carbon and helium isotopes in thermal springs of la soufriere volcano guadeloupe lesser antilles implications for volcanological monitoring abstract la soufriere guadeloupe lesser antilles is one of the most active and dangerous volcanoes of the lesser antilles arc the renewal of the volcanic activity at la soufriere requires replenishment of the volatile poor andesitic stored magma with more primitive volatile rich basaltic magma this event will trigger early release of large quantities of highly volatile species like co 2 and helium in the hydrothermal system to use these precursors first their baseline abundances and their behaviour in the hydrothermal system must be known during the current phase of dormancy in this study we have combined a previous systematic investigation of noble gases with carbon data of hydrothermal fluids flowing out of la soufriere the results for dissolved gases reveal that an intense interaction between rising magmatic volatiles and groundwaters currently takes place at la soufriere we show that the pristine magmatic composition with a 13 c co2 value of 3 19 0 03 a 3 he 4 he ratio of 8 1 0 2 r a and a co 2 3 he ratio of 1 03 0 18 10 10 may vary during the ascent of magmatic fluids due to either fractionation or mixing processes with meteoric water and or an organic component here we provide a baseline for co 2 and helium isotopes at each monitored spring and describe the superficial processes affecting both elemental and isotopic ratios

geochemical behavior of rare earth elements during the evolution of co2 rich groundwater a study from the kangwon district south korea abstract a hydrochemical study of co 2 rich groundwaters in the kangwon district south korea was conducted to elucidate the behavior of rare earth elements ree as a result of mixing of co 2 rich waters the ree fractionation during the formation of carbonate precipitates was also investigated the co 2 rich waters can be classified into three chemical types na hco 3 ca na hco 3 and ca hco 3 with characteristic isotope compositions chemical and isotope data indicate that the na hco 3 waters were influenced by a deep co 2 supply at depth while other waters were formed by mixing between na hco 3 water and less saline shallow groundwater concentrations of total dissolved ree ree in co 2 rich waters varied according to the water types and were highest in the na hco 3 waters up to 3456 ng l their ree concentrations showed excellent correlations with parameters such as tds ph alkalinity 18 o and tritium indicating progressive mixing with shallow groundwater the distribution of dissolved ree concentration showed different patterns dependent upon water type the na hco 3 waters displayed an s shape pattern with strong heavy ree hree enrichment in contrast the ca na hco 3 water was characterized by a slight hree enrichment while the ca hco 3 water exhibited a relatively flat scattered low ree lree enrichment pattern the ree patterns of the precipitates formed from the original waters and of the residual waters after removal of the precipitates were similar to those of the original co 2 rich waters indicating that no ree fractionation occurred between precipitates and residual waters

stable isotope and water quality analysis of coal bed methane production waters and gases from the bowen basin australia abstract coal bed methane cbm is a significant growing industry in queensland s energy sector it is however a relatively new industry with little local water quality data and stable isotope compositions of production waters and gases available in the public domain this study aims to determine whether water quality and stable isotope data can be correlated with gas and groundwater production and flow pathways and identify zones of recharge and water mixing stable isotope analysis and accessory water quality tests were conducted on cbm production gas and water samples collected from two cbm producing bituminous coal seams within a single field in the bowen basin in the production field the reservoir seams are gently folded with eastwardly dipping fold axes and compartmentalised by an ene normal fault on the flank of a broad central anticline that contains minor faults for one seam splitting and a change in coal quality parallels the fault and fold axes although virgin reservoir conditions were similar differing production performance north and south of the main fault suggests it acts as a barrier to water and gas flow along strike the stable isotope analysis on the production water showed that waters with more positive d and 18o compositions were associated with areas of higher water production and shallower depths whereas more negative d and 18o compositions were associated with lower water production and high gas production the gas isotope analysis showed that production gases had both biogenic and thermogenic origins and that secondary biogenic gas generated through co2 reduction comprises a significant portion of the cbm produced from this field more negative ch4 13c values characterize the zones of meteoric recharge in shallow up dip areas gas production data and co2 13c values suggest that this may result from 13ch4 stripping by the recharge waters and or increased biogenic activity in this area smaller co2 ch4 carbon isotopic fractionation values characterized zones of meteoric recharge whereas higher isotopic fractionation values characterized the high gas production domain

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