chemical and isotopical characterisation of fluid manifestations of ischia island italy abstract between 1994 and 1995 gas samples from fumaroles and thermal waters were collected on ischia island the chemical composition of the shallow and deep natural hydrothermal fluids discharged is related to the main hydrological and lithological characteristics of the rock formations present in the reservoir a biphase reservoir liquid gas is identified where the dominant liquid has a temperature of about 280 c on the basis of 13ctdc values it was possible to hypothesize a deep source characterised by carbon isotopic values varying from 0 to 3 these values are noticeably more positive with respect to those attributed to magmatic co2 13 c co 2 ranging from 5 to 8 thus suggesting a magmatic source modified by crustal contamination this hypothesis is supported by the carbon isotopic composition of co2 in sampled gases which varied from 0 to 5 the inferred isotopic value of carbon of magmatic co2 would then be about 2 the observed differences in c isotopic composition between fumarolic and magmatic gases would be caused by kinetic and or equilibrium fractionation processes these processes would cause a fractionation of 13c of deep co2 towards more negative values down to 5 actually co2 removal or addition processes caused by the interaction between deep gases and shallow hydrothermal waters are likely to be responsible for the different chemical and isotopic compositions of gaseous emissions for these reasons and on the basis of the homogeneity of geothermometric values the existence of a single large reservoir that feeds all of the fluids discharged at ischia island can be hypothesised based on acquired data a new geochemical model of the geothermal system of ischia island is proposed

geochemistry of geothermal waters from the gonghe region northwestern china implications for identification of the heat source the gonghe geothermal region located in the northeastern part of qinghai tibet plateau is the most geothermally active in qinghai province the geothermal waters from three hydrothermal areas qiabuqia guide and xinghai of gonghe are characterized with different hydrochemical types nevertheless their d and 18o data suggest that they are all of meteoric origin most gonghe samples are far away from the full equilibrium line in na k mg triangular diagram implying that na k geothermometer is generally not suitable for calculating the reservoir temperatures in comparison silica geothermometers perform much better and give more accurate temperature estimations the hydrochemistry of the gonghe geothermal waters is distinctively different from that of the hot springs from rehai a well known magmatic hydrothermal area located in the tengchong volcanic region of yunnan province southwestern china indicating that the geothermal anomaly in gonghe is not related to an underlying magma chamber instead the strong hydrothermal manifestation there is more likely to be supported by the intense deep tectonic activities moreover the possible existence of radioactive heat source can not be ruled out at this stage

hydrogeochemistry and stable isotopes of thermal springs earthquake related chemical changes along belice fault western sicily abstract three geothermal systems montevago castellammare alcamo and sciacca are located along the main seismogenetic structures in western sicily concentrations of dissolved species including the gases co 2 n 2 he and the results of stable isotope measurements 18 o d and 13 c tdic in water samples collected from six thermal springs and 28 cold discharges were used to characterise their feeder aquifers and to reveal the relationships between water chemistry and regional seismicity the sciacca thermal springs differ chemically and isotopically from those of montevago and the castellammare alcamo areas the inferred deep end members of the thermal waters of montevago and castellammare alcamo are almost similar suggesting that both systems are fed by carbonate waters and selenite waters a slight contribution 1 3 of seawater during groundwater ascent it is also present the sciacca thermal springs are fed by a deep reservoir comprising a mixture of 50 carbonate water and 50 seawater during ascent towards the surface these waters interact with nacl rich evaporite layers by combination of published and present data significant temporal variations of temperature and some chemical parameters in the thermal waters of western sicily have been recorded these variations were mostly between 1966 and 1969 although the data are discontinuous it is still possible to reveal a direct link between physico chemical changes in the acqua pia and terme selinuntine springs and the 1968 belice valley earthquake within the studied springs two kinds of geochemical behaviour have been recognised the chemistry of the montevago thermal springs was permanently changed in response to changes in the groundwater system water temperature and dissolved so 4 cl na and tds showed minimum values before the earthquake and maximum values after the event almost constant values substantially higher than before were recorded after the seismic event conversely the temporal variations observed in the waters of the terme selinuntine spring from 1965 to 1991 exhibit a transient increase most probably caused by a temporary contribution of deep co 2 rich fluids caused by the strain release during the 1968 earthquake

determining the origin of groundwater elements using hydrochemical data case study kerman water conveyance tunnel pollution by heavy metals and potentially toxic elements is one of the main problems in tunneling construction in geothermal and volcanic areas kerman tunnel located in the central parts of iran average base level of 2370 m and length of 38 km plays a key role in water transportation from safa dam to kerman city the tunnel is located at the kerman cenozoic volcanic belt as a southern part of urmia dokhtar volcanic belt the overburden of basement rocks above the tunnel axis is up to 850 m thick and the tunnel cuts across granite diorite andesite trachyandesite and flysch rocks based on the geothermal fluids evidences in the area this study made an attempt to determine the hydrochemical characteristics and the origin of the elements in groundwater this can identify the geological hazards in the tunnel route to this end 31 groundwater samples were collected from 12 boreholes and were then chemically analyzed the results showed that the cations and anions had widely varying concentrations high to ultra high concentrations of as b fe al hco3 and so4 were significant properties of the water samples the results of different diagrams ion ratios and multivariate statistical analysis especially principal component analysis pca and hierarchical cluster analysis hca confirmed that the unique water compositions and characteristics resulted from rock water interaction and mixing of geothermal and meteoric water

hydrochemical and isotopic characteristics of groundwater in the yanqi basin of xinjiang province northwest china in this study hydrochemical and isotope investigations were conducted in the yanqi basin to determine the chemical composition and to gain insight into the groundwater recharge process in the yanqi basin it mainly used hydrochemistry environmental isotopes and a series of comprehensive data interpretation e g statistics ionic ratios and piper diagram to obtain a better understanding of the functioning of the system the following hydrochemical processes were identified as the main factors controlling the water quality of the groundwater system weathering of silicate minerals dissolution ion exchange and to a lesser extent evaporation which seemed to be more pronounced down gradient of the flow system as groundwater flows from the recharge to discharge areas chemical patterns evolve in the order of ca2 hco3 ca2 mg2 hco3 to ca2 mg2 cl so4 2 na k cl so4 2 and na cl according to lithology the environmental isotope 18o 2h 3h measurements further revealed that precipitation was the main recharge source for the groundwater system some local values indicated high levels of evaporation tritium and cfc analysis were used to estimate the ages of the different groundwater the tritium values of the groundwater samples varied from 2 82 to 29 7 tu the age of the groundwater at depths of 120 m is about 30 50 years cfc values obtained for six samples to determine groundwater age the age of the groundwater is about 20 50 years

hydrochemical characteristics and mixing behavior of thermal springs along the bijiang river in the lanping basin of china the lanping simao basin characterized by the occurrence of hydrothermal activities in the northern part of the basin is the largest depression basin in western yunnan province hot springs outcrop in the semi drought red layers tds 0 644 8 17 g l mixing with shallow cold water in the flow system is the dominant hydrogeological process leading to the decrease in thermal water temperature and complex hydrochemical compositions with water types ranging from hco3 ca mg to cl na type according to the silicon concentration and enthalpy evaluation the geothermal reservoir temperatures are estimated between 118 and 204 c and the mixing ratio between cold and thermal groundwater is 0 76 on the average the high concentrations of na and cl indicate that there is some well mineralized cold water in the flow system circulating to the upward migration path accompanied with intense water rock reactions in the fault developed basin ca and so4 originate from progressively longer flow path owing to the poor solubility of gypsum anhydrite and ca montmorillonite hierarchical clustering and multivariate statistical methods recognized three hot springs groups and four parameters groups which classified the reservoir environment into two situations one is in the high pressure environment with intense degassing and the other is in the lower pressure with weak minerals migration

interaction between the deep fluids and the shallow groundwaters on vulcano island italy the aim of this work is to study the interactions processes between the fluids of deep origin and the shallow groundwaters of the vulcano porto area during 1995 13 well waters were sampled three times may july and november and analysed for major and some minor elements b br and nh4 and for dissolved gases the close relationship of these waters with the deep magmatic source is highlighted by the composition of the dissolved gases furthermore the areal distribution of dissolved species is controlled mainly by the gas fluxes from depth and by the presence of a deeper thermal aquifer the distribution of major anomalies in the parameters measured in the groundwaters in fact overlaps the soil gas fluxes distribution that are related to the existence of preferential upflow routes of fumarolic fluids through weak structural lines in the volcanic edifice

hydrochemistry and geothermometrical modeling of low temperature panticosa geothermal system spain abstract the chemical characteristics of the low temperature geothermal system of panticosa spain were investigated in order to determine the water temperature at the reservoir and to identify the main geochemical processes that affect the water composition during the ascent of the thermal waters in general the studied waters are similar to other geothermal systems in the pyrenees belonging to the group of granite related alkaline thermal waters high ph low total dissolved solids very low magnesium concentration and sodium as the dominant cation according to the alkaline ph of these waters they have a very low co 2 partial pressure bicarbonate is the dominant anion and silica is partially ionized as h 3 sio 4 the unusually active acid base pairs hco 3 co 3 2 and mainly h 4 sio 4 h 3 sio 4 act as homogeneous ph buffers and contribute to the total alkalinity in these alkaline waters on the basis of the study of the conservative elements a mixing process between a hot and a cold end member has been identified additionally in order to determinate the water temperature at the reservoir several geothermometric techniques have been applied including both geothermometrical modeling and classical geothermometrical calculations the geothermometrical modeling seems to indicate that thermal waters re equilibrate with respect to calcite and kaolinite during their ascent to the surface modeling results suggest that these thermal waters would be in equilibrium with respect to albite k feldspar quartz calcite kaolinite and zoisite at a similar temperature of 90 20 c in the reservoir which is in good agreement with the results obtained by applying the classical geothermometers

measuring the sea ice floe size distribution sea ice is broken into floes whose diameters range from meters to a hundred kilometers this fragmentation affects the resistance of the ice cover to deformation and the melting at floe sidewalls in summer floes are broken by waves and swell near the ice edge and throughout the pack by isostatic imbalances thermal cracking winds and currents in winter they are welded together by freezing floe size can be measured by several properties p for instance area or mean caliper diameter two definitions of floe size distribution seem useful f p the fraction of area covered by floes no smaller than p and n p the number of floes per unit area no smaller than p f p can be measured by sets other than areas such as the fraction of a line or of a point set covered by floes no smaller than p if n behaves like for small where is mean caliper diameter must be greater than 2 so that the small floes occupy finite area if 2 1 the perimeter of small floes is infinite several summertime distributions have been measured on a log log graph their slopes local values of range from 1 7 to 2 5 one distribution follows a power law the others have steeper slopes for larger floes and more gradual slopes for smaller floes another sampling strategy is to measure the lengths of line segments on floes the distribution of these chord lengths is equivalent to the distribution of floe diameters the variance of an estimate of the fraction g of area covered by floes in any size range is g 1 g k 1 where k is the equivalent number of independent samples k can be found from the autocovariance of the indicator function for the chosen size range for line sampling of a narrow range of floe diameters k is the ratio of the sample length to the floe diameter

secondary processes determining the ph of alkaline waters in crystalline rock systems abstract the understanding of the main hydrogeochemical processes controlling the features and behaviour of crystalline rock environments considered for the deep geological storage of spent nuclear fuel is a key issue for the improvement of our knowledge and management of these systems and for a more accurate prediction of their future evolution in this paper some of the most important irreversible processes cooling mixing and co 2 exchange are studied and their effects quantified by combining classical geochemical calculations and geochemical modelling this methodology is applied to an alkaline thermal water system developed in crystalline rocks the caldas de boi groundwater system ne spain analogous to the deep geological environments expected for nuclear waste storage one of the most remarkable results obtained in this study is related to the high ph buffering capacity exhibited by these alkaline thermal waters during the mixing processes with colder and shallower waters taking place during the uprising of the hot waters from the deep reservoir even for high mixing proportions of cold water up to 60 the final ph remains as alkaline as in the thermal and deep end member although the rest of the physicochemical parameters including temperature change consistently with mixing another important secondary ph determining process detected in this study is the conductive cooling of the thermal waters suffered during their rise to surface conditions which is clearly responsible for a ph increase which enhances the typical alkaline character of these waters finally the existence of external inputs of edaphic or biogenic co 2 to the groundwater system producing a ph decrease in some of the springs has been proven to play a key role in their behaviour and evolution

inversion of pack ice elastic wave data to obtain ice physical properties geophones mounted on floating ice sheets can potentially provide data for a robust method to monitor mechanical properties of the ice the technique relies on the measurement and inversion of low frequency elastic waves propagating in the ice to test this hypothesis several geophone systems were deployed on the arctic ice as part of the office of naval research sea ice mechanics initiative simi including a winter over system of 20 triaxial geophones at the fall 1993 simi camp an inversion technique is discussed here through references to the literature and by analysis of geophone data specifically those data collected on clean first year ice off resolute bay canada and on highly irregular multiyear ice found at the fall simi camp for undeformed first year ice the inversion technique gave an estimate of ice properties that agreed well with known values although extensive work remains to determine the effects of anisotropy and inhomogeneity the geophone data for the nonuniform ice at the simi camp were very complex and difficult to analyze the inversion yielded only trends in what can at best be termed effective ice thickness and bending rigidity it is uncertain how these relate to actual ice properties the simi geophone system demonstrated the feasibility of performing autonomous measurements of the characteristics of propagating waves in the arctic ice with continued study it seems evident that such systems can be used in clean first year ice to monitor ice properties however extensive research is required to make this technique useful in multiyear or complex first year ice

geology and geochemistry of amealco caldera qro mexico amealco caldera located in the central part of the mexican volcanic belt mvb about 130 km nw of mexico city is characterized by a quasi circular 11 km diameter structure whose southern portion is partly truncated by a regional fault the caldera was formed 5 m y ago due to a voluminous eruption of 65 km3 eq magma volume of ignimbrites which covered an area of 1800 km2 this was followed by eruption of 2 km3 of andesitic and dacitic lava flows from the border of the caldera and emplacement of a total of 8 silicic rhyolitic domes 8 km3 inside the caldera finally postcaldera volcanism 4 km3 consisted of extrusion of andesitic and basaltic andesite lavas and scoriae we have analyzed 17 representative rock samples for their major and trace element contents by x ray fluorescence spectrometry and for rare earth elements by high performance liquid chromatography all samples were also analyzed for their sr and nd isotopic compositions which range as follows 87sr 86sr 0 70379 0 70451 143nd 144nd 0 51267 0 51278 the chemical and isotopic data are used to constrain the origin and evolution of magmas in the caldera no combination of altered morb and overlying sediments from the subducted slab cocos plate can produce the sr and nd isotopic compositions observed in rocks from amealco caldera further modelling reveals that the mantle derived primary magmas in amealco caldera may have assimilated up to 10 of a crustal component during their evolution from basaltic andesites to dacites but no further assimilation appears to have taken place during the evolution of the rhyolitic magmas the structure and genesis of the amealco caldera are comparable to some other calderas of the mvb

geothermometry and circulation depth of groundwater in semnan thermal springs northern iran semnan thermal springs with high tds and moderate temperature are located northwest of semnan the northern part of iran the spatial and temporal variations of physicochemical characteristics of the thermal and cold springs were investigated for the recognition of origin and dominant hydrogeochemical processes results show that the thermal springs have the same origin but due to different ascending flow paths and different conductive cooling mechanism their temperatures vary the chemical composition of thermal waters is controlled by dolomite halite and sulfate minerals dissolution and calcite precipitation and bacterial sulfate reduction the concentration of major and trace elements in the thermal springs does not change in wet and dry seasons notably because they are derived from old groundwater with deep circulation and high temperature seasonal change in the concentration of some trace elements is due to the seasonal variation of ph eh temperature and dilution by shallow waters decreasing so4 and carbonate saturation index and increasing na cl ratios and ca content in the dry season show dilution effect caused by the previous heavy rainfall events the temperature of the heating reservoir based on k mg chalcedony quartz and chemical equilibrium approach was approximately estimated in the range of 60 80 c hydrogeologically a conceptual model was suggested for the thermal springs the general groundwater flow direction is probably from the dolomite lar formation in chenaran anticline toward the adjacent syncline in a confined condition and then a thrust fault acts as a conduit and redirects the thermal water to the emerging springs at the surface

geochemistry of hot springs in the tengchong hydrothermal areas southwestern china abstract as an important volcanic geothermal region in china tengchong belongs to the mediterranean himalayas geothermal belt and is characterized by wide distribution of volcanic rocks fifty eight hydrothermal areas have been identified in tengchong among which the rehai hydrothermal system is the most geothermally active the geothermal waters from rehai are mainly na hco 3 cl and na hco 3 types whereas those from the other hydrothermal areas are mainly na hco 3 na ca hco 3 ca hco 3 ca mg hco 3 mg na ca hco 3 and mg ca hco 3 types both quartz geothermometer and k mg geothermometer indicate that the rehai geothermal field has higher subsurface temperatures than the other hydrothermal areas except for three rehai samples most geothermal water samples collected from tengchong are far from the full equilibrium line in giggenbach s triangular diagram suggesting that the complete chemical re equilibrium has not been achieved as these geothermal waters flow upward from reservoirs towards spring vents and possibly mix with cooler waters statistical analysis shows that cl b li rb and cs are the characteristic constituents of the tengchong geothermal waters and the good linear relations among these elements in the rehai geothermal waters reflect the existence of a deep parent geothermal liquid pgl below rehai an enthalpy chloride diagram of the rehai geothermal waters suggests that the parent geothermal liquid has cl concentration of 291 mg l and enthalpy of 1495 j g the pgl ascends to the surface through different channels and may cool by conduction of heat to reservoir host rocks by boiling or by mixing with cooler shallow groundwaters

the nature of mineralizing fluids of the kipushi zn cu deposit katanga democratic repubic of congo quantitative fluid inclusion analysis using laser ablation icp ms and bulk crush leach methods fluid inclusions from the epigenetic zn cu deposit of kipushi central african copper belt katanga democratic republic of congo have been subjected to an integrated microthermometric bulk crush leach and laser ablation inductively coupled plasma mass spectrometric la icp ms study to elucidate the physicochemical conditions of ore formation and the origin of the mineralizing fluids the kipushi deposit is hosted in carbonates and partly in siliciclastic rocks that have undergone regional low grade greenschist facies metamorphism and which were strongly deformed during the lufilian orogeny main deformation phase 550 ma investigation of host rock gangue and ore samples enabled reconstruction of the paragenesis of ore deposition the main zn cu ge pb sulfide mineralization was accompanied by three generations of hydrothermal dolomite and a generation of coarse grained quartz primary and pseudosecondary fluid inclusions in these minerals contain predominantly halite saturated aqueous brines 30 43 wt nacl equiv with locally unidentified trapped solids these inclusions mostly decrepitate upon heating before total homogenization which could suggest that they also trapped excess carbonic vapor they show petrographic and microthermometric evidence for postentrapment reequilibration prohibiting their use as accurate geothermometers and geobarometers previous studies on chlorite and sphalerite geothermometry framed the formation temperature of the kipushi cu zn deposit between 290 to 380 c younger fluids are present as secondary inclusions in the gangue minerals and as primary fluid inclusions in sphalerite from a minor secondary mineralization phase these two phase aqueous inclusions have a slightly lower salinity 23 31 wt nacl equiv and have homogenization temperatures ranging from 170 to 80 c in successive fluid inclusion assemblages sporadically some mixed aqueous carbonic and gaseous co2 ch4 inclusions are present but their genetic position is un clear and they are insignificant with regard to the mineralization process as a whole crush leach bulk analysis of the fluid inclusions show that the mineralizing fluids had a molar cl br ratio close to or somewhat higher than the seawater value which rules out a major contribution from bittern brines and suggests that the fluids gained their salinity primarily by the dissolution of evaporites younger fluids that circulated through the deposit after the main phase of ore formation have cl br and na br signatures indicative of a greater involvement of halite dissolution brines values much higher than that of seawater la icp ms analyses of the mineralizing fluids reveal that they have molar li na ca na mg na mn na and sr na in the range of natural high salinity fluids in metamorphic environments worldwide however they have relatively high molar fe na zn na pb na and especially very high ba na ratios their molar k na is also somewhat higher than for other low grade metamorphic fluids but is nevertheless in agreement with the values predicted by the k na geothermometer at the conditions of ore formation this suggests that the major element composition of the fluids was buffered by fluid mineral equilibria their relatively high metal contents ba zn fe and pb suggest that they interacted with and leached these elements from felsic basement rocks at higher temperatures whatever the origin of the fluids their salinity and the metals their uniformly high ba and ore metal content together with the absence of barite and the occurrence of ba silicates at kipushi indicates that sulfide mineralization occurred when the metal bearing fluids encountered a reducing h2s rich reservoir the ubiquitous presence of preexisting metamorphosed carbonic material shungite in the sulfides and host rock and a sulfur isotope signature of the ores in agreement with thermogenic sulfate reduction suggests that this condition was likely created due to the high initial reduced carbon content of the host rocks at kipushi which seems to be exceptional in the copper belt therefore we postulate that a critical factor in the formation of major vein type zn cu mineralization was the presence of a hydrocarbon rich facies of the lower nguba carbonates at kipushi

arsenic enrichment in groundwater of west bengal india geochemical evidence for mobilization of as under reducing conditions abstract the mechanism of as release and source s of as has been investigated in a small part of a watershed in the murshidabad district of west bengal analyses include major ion and trace element concentrations as well as o h and s isotope ratios of groundwater surface water and a thermal spring the results indicate that all water samples belong to the ca hco 3 type except for the thermal spring which is of the na hco 3 type shallow and deeper groundwaters have distinct hydrochemical features high as contents were registered only in the deeper groundwater horizon factor analysis and the distribution pattern of major and trace elements indicate that as is present in the aquifer as a scavenged phase by fe iii and to a lesser extent by mn iv phases the release of as into the groundwater occurs gradually in successive stages corresponding to the actual redox state in the aquifer the main stage of as release is related to the bacterial reduction of fe iii to fe ii i e to the simultaneous dissolution of fe oxyhydroxides low redox conditions in highly polluted areas are indicated by low so 4 concentration and high 34 s values during bacterial so 4 reduction residual so 4 in groundwater is depleted in the lighter s isotope 32 s however the cause of the gradual decrease of the redox state in the groundwater is still not well understood

water geochemistry and soil gas survey at ungaran geothermal field central java indonesia abstract a soil gas survey for radon rn thoron tn co 2 and mercury hg and the chemical analysis of hot spring waters were undertaken in the ungaran geothermal field central java indonesia the results of soil gas surveys indicate fault systems trending nne ssw and wnw ese particularly high co 2 concentrations 20 and high hg concentrations were detected in vicinity of the fumaroles emanometries of rn tn and co 2 also conclusively identified the presence of a fracture zone for the migration of geothermal fluid the hg results infer that the up flow zone of high temperature geothermal fluids maybe located in the north of fumaroles in the gedongsongo area near the collapse wall chemistry of thermal springs in the up flow zone are acid ph 4 and show a ca mg so 4 composition the thermal waters are mainly ca mg hco 3 and ca na so 4 hco 3 types near the fumarolic area and are mixed na ca cl hco 3 waters in the south east of gedongsongo the 18 o between 5 3 and 8 2 and between 39 and 52 indicate that the waters are essentially meteoric in origin a conceptual hydro geochemical model of the gedongsongo thermal waters based on the soil gas isotope and chemical analytical results was constructed

hydrogeochemistry of thermal and mineralized waters in the diyadin agri area eastern turkey abstract the diyadin geothermal area located in the eastern part of anatolia turkey where there has been recent volcanic activity is favorable for the formation of geothermal systems indeed the diyadin geothermal system is located in an active geodynamic zone where strike slip faults and tensional cracks have developed due to n s regional compression the area is characterized by closely spaced thermal and mineralized springs with temperatures in the range 30 64 c and flowrates 0 5 10 l s thermal spring waters are mainly of ca na hco 3 and ca mg so 4 types with high salinity while cold groundwater is mostly of ca na mg hco 3 type with lower salinity high contents of some minor elements in thermal waters such as f b li rb sr and cs probably derive from enhanced water rock interaction thermal water samples collected from diyadin are far from chemical equilibrium as the waters flow upward from reservoirs towards spring vents and possibly mix with cooler waters the temperatures of the deep geothermal reservoirs are estimated to be between 92 and 156 c in diyadin field based on quartz geothermometry while slightly lower estimates are obtained using chalcedony geothermometers the isotopic composition of thermal water 18 o 2 h 3 h indicates their deep circulating meteoric origin the waters are likely to have originated from the percolation of rainwater along fractures and faults to the deep hot reservoir subsequent heating by conduction due to the presence of an intrusive cupola associated with the tendurek volcano is followed by the ascent of deep waters to the surface along faults and fractures that act as hydrothermal conduits modeling of the geothermal fluids indicates that the fluid is oversaturated with calcite aragonite and dolomite which matches travertine precipitation in the discharge area likewise the fluid is oversaturated with respect to quartz and chalcedony indicating the possibility of siliceous precipitation near the discharge areas a conceptual hydro geochemical model of the diyadin thermal waters based on the isotope and chemical analytical results has been constructed

emplacement of a large igneous province as a possible cause of banded iron formation 2 45 billion years ago latest archaean and earliest palaeoproterozoic times from 2 6 to 2 2 billion years ago have generally been viewed as a largely quiescent period of earth history the geological record indicates the very slow deposition of pelagic and chemical sediments1 2 and bears only a limited record of magmatic and tectonic activity3 5 such quiescence is consistent with the contention that the earth s main banded iron formations bifs finely laminated chemical sedimentary rocks rich in iron oxide formed slowly as oxygen abundances in the oceans gradually increased thus reducing the capacity of sea water to retain dissolved iron6 10 here we show that a large igneous province comprising 30 000km3 of dolerite basalt and rhyolite accompanied deposition of a hamersley province bif 2 449 3 million years ago this observation indicates that hamersley bifs formed during a major tectono magmatic event and were deposited very much faster than previously thought at similar rates to or faster than modern pelagic sediments thus the largest palaeoproterozoic bifs rather than simply reflecting a gradual increase in the oxygen content of the oceans during a period of tectonic quiescence are more likely to have formed as a result of an increased supply of suboxic iron and silica rich sea water upwelling onto continental shelves during a pulse or pulses of increased submarine magmatic and hydrothermal activity

origins and mixing contributions of deep warm groundwater in a carbonate hosted ore deposit sichuan yunnan guizhou pb zn triangle southwestern china abstract sichuan yunnan guizhou syg carbonate hosted pb zn triangle is a world class metallogenic belt and classified as mississippi valley type mvt which provides the greatest ore production in china however little is known about the effects of water rock interactions involving the ore deposits and the modern hydrologic system measured chemical and isotopic compositions of the deep groundwater are used to evaluate water origins potential circulation depth reaction temperatures and mixing process with shallow groundwater to assess possible linkages between regional hydrogeology and ore deposits within the maoping sub deposit deep groundwater is warmer 21 2 32 0 c has lower ph higher hco3 and so42 concentrations higher average 87sr 86sr ratio 0 7148 and sr concentration 4 1 mg l more positive 13cdic values 4 5 to 4 2 and lighter average isotopic value d 98 and 18o 13 7 relative to shallow groundwater suggesting an origin distinct from modern surface recharge the light isotopic composition of the deep warm water indicates recharge at a cooler temperature in the past perhaps during the last glacial maximum the 13cdic values reflect isotopic equilibrium between deep groundwater and surrounding rocks along with a possible deep source of co2 the oxidation process of sulfides including h2s and pyrite linked to the ore forming processes could produce sulfuric acid that enhances carbonates dissolution and generates elevated hco3 and so42 concentrations reaction temperatures for the deep groundwater appear to have been around 50 65 c based on quartz geothermometers and given a regional geothermal gradient of 24 1 c km suggest reactions occurred at depths 1900 m below the land surface elevated sr concentrations with radiogenic sr isotope ratios reflect reaction with basement rocks and carbonates during the deep circulation sr concentration and isotope mixing models demonstrate different recharge sources and suggest the contribution of deep warm groundwater captured in mine drainage these results reflect the importance of deep groundwater circulation and reactions in a large ore deposit that may improve understanding of potential effects of these important ore bodies on regional water compositions in the syg triangle and other mvt ore deposits

water geochemistry of the seferihisar geothermal area izmir turkey abstract the na cl thermal waters of seferihisar have measured temperatures of 30 153 c and conductivities of 7400 55200 s cm they issue from upper cretaceous to paleocene bornova melange rocks which are made up of sandstone shale intercalations conglomerate mafic submarine volcanics limestone lenses serpentinite and limestone bodies and their complexes through the intersection of faults the clay rich zones of the overlying neogene terrestrial sediments cap the system the heat source is the high geothermal gradient caused by graben tectonics of the area na and cl ions mainly dominate the chemistry of thermal waters thus thermal waters of the seferihisar area appear to be mixtures of groundwaters and seawater the seawater contribution in thermal waters varies from 10 to 80 assessments from empirical chemical geothermometers mineral equilibria and silica mixing model applied on the thermal waters of the seferihisar geothermal area suggest that the temperatures of the reservoir systems vary between 60 and 180 c the seferihisar geothermal area has been physically divided into five main groups and estimated reservoir temperatures provided by the entire methods give the increase as doganbey burnu karakoc spa doganbey tuzla and cumali spa areas in ascending order of reservoir temperature hydrogeochemical assessments indicate that thermal waters were mixed with cold waters before and or after heating at depth in different proportions the results of mineral equilibrium modeling indicate that the thermal waters of seferihisar are undersaturated with respect to gypsum and amorphous silica oversaturated with respect to calcite dolomite and aragonite and undersaturated or oversaturated with respect to quartz chalcedony and anhydrite

new improved equations for and sio2 geothermometers by outlier detection and rejection abstract we present new improved equations for three still widely used na k na li and sio 2 geothermometers obtained by statistical treatment of the data and application of outlier detection and rejection as well as theory of error propagation and compare them with those by fournier and others new equations are also developed for estimating errors associated with the use of these new geothermometric equations and comparing them with the performance of the original equations the errors in the use of the new na k equation for temperatures ranging from 80 to 350 c vary from about 19 to 34 which is lower than the corresponding errors 24 43 for the original fournier equation similarly for temperatures ranging from about 50 to 320 c our new equation for na li geothermometer for cl 2 2 geothermometer we have proposed a linear equation for the temperature range of 210 to 310 c sio 2 295 ppm which shows considerably smaller total propagated errors 2 3 than for the original equation 5 29

origin and evolution of the thermal waters from the pamukkale geothermal field denizli basin sw anatolia turkey insights from hydrogeochemistry and geothermometry abstract the pamukkale geothermal field pgf of the denizli basin sw turkey is one of the most distinguished active geothermal fields known in the world the thermal waters from the pgf are subdivided into two groups group 1a ca hco3 and group 1b ca so4 types the cold waters are also classified into two groups group 2a ca hco3 and group 2b mg hco3 types the hydrogeochemical properties of the pgf thermal waters suggest interactions with the basal metamorphic rocks of the menderes massif tectonically overriding by the carbonate rocks of the lycian nappes and sedimentary rocks of the neogene formations the bedrock units are stratigraphically overlain by the neogene sedimentary units of the denizli group the thermal springs of the pgf are affected by several hydrothermal processes including mixing water rock interaction and input of mantle volatiles the thermal water plots of the pgf deviate from the full equilibrium line indicating a low water maturity and or mixing processes mixing models and na k mg ternary diagram suggest mixing between meteoric and thermal waters during the uprising of the deep originated fluids the water rock interaction leads saturation of calcite and induces travertine precipitation in the discharge area low tritium this study proposes a conceptual hydrogeological hydrogeochemical tectonic model for the pgf the thermal waters are derived from the infiltration of rainwater through fractures and faults in high recharge areas to the deep hot reservoir heating produced by the high geothermal gradient is interpreted in relation with the regional crustal thinning thermal waters upwell along wnw ese trending deep faults and fractures the pamukkale fault system that act as hydrothermal pathways favouring migration of a huge amount of co2 rich gas from deep geothermal reservoir the geochemical and isotopic data of the thermal waters and gas indicate that the degassing of both metamorphic co2 and mantle derived co2 occurs in the pgf helium isotope data indicate that mantle volatiles produce possibly an upwelling into asthenosphere and ascent along these tectonic discontinuities in this context the pgf is one of the best example of geothermal fields as an interaction of active magmatism in the actively extending crustal setting

hydrothermal water rock interaction and the redistribution of li b and cl in the taupo volcanic zone new zealand abstract lithium b and cl occur as trace elements in the dominant protoliths rhyolite andesite and greywacke underlying high temperature hydrothermal systems in the taupo volcanic zone tvz the fluid mobility of li decreases substantially at 200 c 20 c with the pervasive deposition of quartz chlorite regardless of protolith and altering fluid compositions boron and cl are more fluid mobile than li at all temperatures with mobility affected by the rock type composition of circulating aqueous solutions and to a limited extent by incorporation of the trace elements in hydrothermal minerals uptake of b by clays decreases its mobility at 320 c occur compared to volcanic rocks the mobility of b and cl in greywackes is very low and thus the b cl signature of greywacke in hydrothermal aqueous solutions of the tvz is overwhelmed by the effects of rhyolite and andesite dissolution temperature dependent transitions from mg fe clays and phyllosilicates to k bearing illitic clays tend to decrease the mg li ratios in aqueous solutions at 200 c

ocean surface wave evolvement in the arctic basin 1 recent basin scale changes to the compactness and thickness of arctic sea ice foreshadow that encroaching swells and locally generated waves will exert more influence there in the future indeed it is conceivable that waves may have already hastened the adjustments observed by breaking up ice floes yet waves advancing in sea ice attenuate due to being scattered from ice thickness variations and damped by ice inelasticity turbulence and friction while past research focuses on scattering by unnaturally perfect features in the ice the model reported herein assimilates realistic basin scale swathes of heterogeneous ice and parameterizes damping by way of example we show how an ocean wave train evolves during its passage in an 1670 km long arctic sea ice profile obtained from submarine

hydrochemical isotopic and hydrogeological conceptual model of the las tres virgenes geothermal field baja california sur mexico abstract based on geological structural hydrochemical and isotopic data a hydrogeological conceptual model for the geothermal reservoir shallow wells and springs at the las tres virgenes geothermal field and its surroundings is proposed the model explains the genesis of different types of thermal and cold groundwater in the nw el azufre valley las tres virgenes and aguajito complex ne reforma complex and s sierra mezquital areas shallow groundwater of sulfate type in the nw zone is explained by the rise of co2 h2s vapor from a shallow magma chamber and the subsequent heating up of a shallow aquifer vertical communication between the reservoir and the surface is facilitated by a series of extensional nw se trending normal faults forming the graben structures of the santa rosalia basin low permeability characteristics of the geological formations of the study area support the hypothesis of a fracture and fault dominated subterranean flow circulation system the na cl hco3 composition of springs in the ne and se zones indicates influence of ascending geothermal fluids facilitated by radial fault systems of the reforma caldera and probably the existence of a shallow magma chamber close to the surface the rising geothermal fluids are mixed up with meteoric water from a shallow aquifer the las tres virgenes and the reforma complex are separated by younger n s trending lateral shearing faults such as the cimarron fault such disposition explains the genesis of different hydrogeological flow regimes on both sides hco3 type surface water from the southern zone between san ignacio and mezquital is of typical meteoric origin with no influence of geothermal fluids due to arid climatic conditions in the study zone recent recharge in the geothermal area seems improbable thus recent interaction between the surface and the geothermal reservoir can be excluded furthermore isotopic and hydrochemical data exclude the presence of marine water from the gulf of california in the deep reservoir both conditions indicate recharge of the reservoir by meteoric water during glacial periods in holocene or pleistocene time or a magmatic origin of the reservoir fluids the slightly positive slope of the 18o d line of geothermal fluids and its intermediate isotopic composition between the surface samples and magmatic andesitic water indicate that magmatic andesitic water contributes approximately 30 to the geothermal fluid composition whereas fossil meteoric water represents the major component 70 the geothermal reservoir is considered to represent a hydrostatic stagnant flow system based on the observed linear correlation between the isotopic composition and the altitude of the surface manifestations the isotopic composition and altitude of the former recharge were determined as 18 o 9 7 and d 67 3 and 350 m a s l respectively this altitude is interpreted as mean average recharge elevation scarcity of permanent rivers low density of springs and domestic wells as well as low precipitation rates reflect restricted distribution of shallow groundwater systems in the study zone these systems are related to isolated local aquifers composed of valley fillings

hydrogeochemistry and geothermometry of the carbonate evaporite aquifers controlled by deep seated faults using major ions and environmental isotopes abstract carbonate aquifers probably constitute the most important thermal water resources in non volcanic areas and are characteristic of great energy potential and easier production as the most ideal targets for development in the future the thermal waters in the aquifers within southeast chongqing sec of china occur in an extensive region with an area of 198 000 km2 which are mainly hosted in the cambrian and ordovician carbonate evaporite rocks the thermal waters are mainly in pristine conditions and their genesis has not yet been fully understood the occurrence of thermal waters in sec is closely related to the presence of deep seated faults which constitute pathways for the hydrothermal circulation in this study an investigation of water major ions and environmental isotopes from 14 hot springs and three drilled wells was carried out to examine their hydrogeochemical evolution and to estimate reservoir temperature the thermal waters have outflow temperatures from 19 to 54 2 c they are divided into two hydrochemical groups with the yushan fault as a boundary group a located to the west of the fault are characterized by facies of chloride sodium waters with higher tds group b to the east of the fault are more complicated sulfate bicarbonate chloride alkaline earth waters with lower tds the hydrochemical processes such as dissolution of carbonate gypsum and or anhydrite and halite the common ion effect and dedolomitization are evident based on the major ions and 34sso4 and 18oso4 the 18o and d compositions of the thermal waters suggest a meteoric recharge in a relatively wetter and colder climatic condition the silica geothermometers show that the average reservoir temperatures are 63 18 c for group a and 82 15 c for group b the corresponding average reservoir depths are estimated to be 2 5 0 7 km for group a and 3 2 0 7 km for group b the corrected 14c ages of the thermal waters average at 14 8 ka bp corresponding to the late pleistocene a conceptual circulation model is proposed for the thermal waters driven by gravity of topographic gradients the percolating groundwater circulates at a specific depth reaching a higher temperature and interacting with the host carbonate with imbedded evaporitic minerals gypsum and or anhydrite and additional halite for group a to be saline deep seated thermal fluids the fluids rise along faults and emerge at the surface as thermal springs the slow renewability rate of the thermal aquifers highlights the importance of assessing the resource before groundwater exploitation and extraction

low frequency bursts of horizontally polarized waves in the arctic sea ice cover we report the detection of bursts of low frequency waves typically f 0 025 hz on horizontal channels of broadband seismometers deployed on the arctic sea ice cover during the damocles developing arctic modeling and observing capabilities for long term environmental studies experiment in spring 2007 these bursts have amplitudes well above the ambient ice swell and a lower frequency content their typical duration is of the order of minutes they occur at irregular times with periods of relative quietness alternating with periods of strong activity a significant correlation between the rate of burst occurrences and the ice cover deformation at the 400 km scale centered on the seismic network suggests that these bursts are caused by remote episodic deformation involving shearing across regional scale leads this observation opens the possibility of complementing satellite measurements of ice cover deformation by providing a much more precise temporal sampling hence a better characterization of the processes involved during these deformation events

deep geothermal processes acting on faults and solid tides in coastal xinzhou geothermal field guangdong china abstract this paper investigated the deep fault thermal flow processes in the xinzhou geothermal field in the yangjiang region of guangdong province deep faults channel geothermal energy to the shallow ground which makes it difficult to study due to the hidden nature we conducted numerical experiments in order to investigate the physical states of the geothermal water inside the fault zone we view the deep fault as a fast flow path for the thermal water from the deep crust driven up by the buoyancy temperature measurements at the springs or wells constrain the upper boundary and the temperature inferred from the currie temperature interface bounds the bottom the deepened boundary allows the thermal reservoir to revolve rather than to be at a fixed temperature the results detail the concept of a thermal reservoir in terms of its formation and heat distribution the concept also reconciles the discrepancy in reservoir temperatures predicted from both quartz and na k mg the downward displacement of the crust increases the pressure at the deep ground and leads to an elevated temperature and a lighter water density ultimately our results are a first step in implementing numerical studies of deep faults through geothermal water flows future works need to extend to cases of supercritical states this approach is applicable to general deep fault thermal flows and dissipation paths for the seismic energy from the deep crust

seismic acoustic sensing of sea ice wave mechanical properties sea ice inhomogeneities can be probed by seismic and acoustic waves observations of the seismic acoustic response of first year sea ice to artificially generated impacts created by dropping a lead ball from a fixed height show that an ice ridge in the path of a propagating seismic wave dampens the wave this damping effect is found to be sensitive to the angle of incidence especially at high frequencies 100 hz both the longitudinal p wave and horizontally polarized shear sh wave speeds are found to be much more variable in the vicinity of the ridge outside of the ridged area the shear wave speed is relatively uniform varying by only 13 in contrast to the 27 variability of the p wave speed the crary wave which is a special case of the vertically polarized wave sv is most easily induced by seafloor reflected acoustic waves penetrating the ice at large grazing angles when an ice sheet is struck with a vertical blow it radiates sound with a dipole pattern the radiated frequency also depends on the radiation angle with higher frequency energy projected preferentially downward most of the potential energy resulting from artificial impacts is dissipated through damaging the ice surface with only a small fraction being converted into acoustic and seismic waves

a hot spring in granite of the western tianshan china the western tianshan range is a major cenozoic orogenic belt in central asia exposing predominantly paleozoic rocks including granite ongoing deformation is reflected by very rugged topography with peaks over 7000 m high active tectonic deformation is tied to an e w trending fracture and fault system that sections the mountain chain into geologically diverse blocks that extend parallel to the orogen in the muzhaerte valley upwelling hot water follows such a fault system in the muza granite about 20 l min 1 na so4 cl water with a temperature of 55 c having a total mineralization of about 1 g l 1 discharge from the hot spring the water is used in a local spa that is frequented by the people of the upper ili river area its waters are used for balneological purposes and the spa serves as a therapeutic institution the major element composition of the hot water is dominated by na and by so4 and cl ca is a minor component dissolved silica 1 04 mmol l 1 corresponds to a quartz saturation temperature of 116 c and a corresponding depth of the source of the water of about 4600 m this temperature is consistent with na k and na li geothermometry the water is saturated with respect to fluorite and contains 7 5 mg l 1 f as a consequence of the low ca concentration the water is undersaturated with respect to the primary minerals of the reservoir granite at reservoir temperature causing continued irreversible dissolution of granite the waters are oversaturated with respect to ca zeolite minerals such as stilbite and mesolite and it is expected that zeolites precipitate in the fracture pore space and in alteration zones replacing primary granite the stable isotope composition of o and h supports a meteoric origin of the water the cl br mass ratio of 1500 suggests that the salinity results from halite dissolution salts leached from powders of muza granite show the same cl br signature as the hot spring water sodium chloride is stored in fluid and solid inclusions in the granite which have been introduced to quartz by ductile shearing and faulting related to ongoing orogenesis the hot water remobilizes the salt that is continuously liberated by the tectonic deformation water granite interaction contributes a thenardite component na2so4 to the major element composition by albite dissolution in h2so4 the water rock interaction along faults and fractures transforms and alters muza granite to a low temperature epigranite

experimental characterization of elastic waves in a floating ice sheet frequency wave number analysis is applied to geophone data to study phase velocities of ice waves as a function of frequency previous measurements of phase velocities were based primarily on initial arrival time of individual waves which were valid only for the frequency components associated with the initial arrival by processing the geophone array data coherently this frequency wave number analysis measures the phase velocity as a function of frequency for a wide frequency band this processing is applied to geophone data collected on a line array of three axis geophones the data were generated by striking sledge hammers against a steel pipe frozen into the ice during an arctic experiment in 1988 as expected the longitudinal and horizontal shear waves travel with constant phase velocities below 100 hz applying this analysis to vertical axis geophone data we find two families of dispersion curves for the flexural waves only one dispersion curve is expected for the flexural wave for a uniform she

environmental significance and hydrochemical processes at a cold alpine basin in the qilian mountains isotope geochemistry of precipitation river water well water and spring water in the babao river basin china during different seasons showed that regional runoff was dominated by precipitation in summer and autumn and by underground water in winter and spring the 18o and d values of precipitation and spring water displayed a clear altitude effect water from the main stream and tributaries displayed a converse altitude effect in the summer wet season the isotopic composition of the various water sources was not well correlated with elevation during the winter dry season the spatial distribution of the stable isotope signals of river water demonstrated the influence of rainfall inputs evaporation and variable flow an end member mixing model used for hydrograph separation indicated that in the summer wet season the babao river water was recharged by precipitation 71 9 spring water 11 7 and well water 16 4 whereas the winter dry season recharge was sourced from spring water 28 2 and well water 71 8

chemical evolution of saline waters in the jordan dead sea transform and in adjoining areas the ca mg relationship in groundwaters strongly points to the overall dolomitization and local albitization the mg ca ratios reveal two trends by which saline waters develop increase of mg ca ratio by evaporation and decreasing mg ca ratios due to dolomitization and albitization br cl vs na cl ratios demonstrate that albitization does not play a major role which leaves dolomitization to be the main source for decreasing mg ca ratios in saline waters in the eastern and southern region of lake kinneret salinization occurs by mixing with a ca mg molar ratio 1 dominates which developed by the albitization of plagioclase in abundant mafic volcanics and the dolomitization of limestones the most saline groundwater of the tabgha fuliya and tiberias clusters could be regional derivatives of at least two mother brines in diluted form one is represented by ha on water the other is a na rich brine of the zemah type additionally a deep seated ca dominant brine may ascend along the fractures on the western side of lake kinneret which is absent on the eastern side groundwaters of the lower jordan valley are chemically different on both sides of the jordan river indicating that the exchange of water is insignificant all saline waters from the dead sea and its surroundings represent a complex mixture of brines and precipitation and local dissolution of halite and gypsum many wells of the arava araba valley pump groundwater from the upper cretaceous limestone aquifer the origin of the water is actually from the lower cretaceous kurnub group sandstones groundwater drawn from the quaternary alluvial fill either originates from kurnub group sandstones eilat 108 yaalon 117 or from altered limestones of the judea group the origin of these waters is from floods flowing through wadis incised into calcareous formations of the judea group on the other hand as a result of step faulting hydraulic contact is locally established between the kurnub and the judea groups aquifers facilitating the inter aquifer flow of the confined kurnub paleowater into the karstic formations of the judea group two periods of neogene brine formation are considered the post messinan inland lagoon resulting in drying up of the sdom sea and the evaporation of the pleistocene samra lake which went further through the stage of lake lisan to the present dead sea for the first period major element hydrochemistry suggests that the saline waters and brines in the jordan dead sea arava valley transform evolved from the gradual evaporation of an accumulating mixture of sea ground and surface water due to the precipitation of carbonates gypsum and halite such an evaporating primary water body was strongly enriched in mg br and b and shows high molar ratios of br cl b cl and mg ca but low na cl ratios the development of the br cl ratio is chemically modelled showing that indeed brine development is explicable that way along with the evaporation brine evaporites formed which are leached by infiltrating fresh water yielding secondary brines with na cl ratios of 1 when primary brines infiltrated the sub surface they were subjected to mg ca exchange in limestones dolomitization and to chloritization and albitization in basic igneous rocks turning them into ca cl brines these tertiary brines are omnipresent in the rift the brines of the late lisan and dead sea were generated by evaporating drainage waters which leached halite gypsum and carbonates from the soil and from the sub surface all these brines are still being flushed out by meteoric water resulting in saline groundwaters this flushing is regionally enhanced by intensive groundwater exploitation in variable proportions the neogene and late lisan lake and recent dead sea brines have to be considered as the most serious sources of salinization of groundwaters in the rift deep seated pre sdom brines cannot strictly be excluded but if active they play a negligible role only

accurate estimations of sea ice thickness and elastic properties from seismic noise recorded with a minimal number of geophones from thin landfast ice to thick pack ice despite their high potential for accurate sea ice properties estimation seismic methods are still limited by the difficulty of access and the challenging logistics of polar environments conventional seismic methods generally require tens of geophones together with active seismic sources for monitoring applications while this is not an issue for mainland environment it is restrictive for sea ice and prevents long term monitoring we introduce a method to estimate sea ice thickness and elastic properties from passive recordings of the ambient seismic field with a minimal number of geophones in comparison with our previous work moreau et al 2020 where about 50 sensors were used the number of geophones is reduced by one order of magnitude thanks to a new strategy of inversion of the passive seismic data the method combines noise interferometry for estimating the elastic properties with a bayesian inversion of the dispersion in the waveforms of icequakes for inferring ice thickness based on passive recordings from only 3 to 5 geophones depending on the signal to noise ratio we demonstrate its potential both on data recorded on thin landfast ice in svalbard and on data recorded on thick pack ice in the arctic ocean

remobilisation of base metals and gold by variscan metamorphic fluids in the south iberian pyrite belt evidence from the tharsis vms deposit the tharsis massive sulphide deposit one of the major vms type deposits in the iberian pyrite belt ipb was severely deformed by the variscan tectono thermal events the question of whether or not these events affected the metal distribution in the deposit has been addressed by simultaneously studying the mineral parageneses tharsis stockwork and the fluid circulation at local and regional scales the results are 1 the early paragenesis in the stockwork q1 quartz pyrite chlorite phengitefcobaltitefankerite was strongly overprinted by a late post kinematic mineral deposition including new quartz veins q3 quartz and base metal sulphides chalcopyrite sphalerite bi and te minerals pyrite and galena and gold 2 at a regional scale fluids accompanying the peak metamorphism conditions ca 300 mpa ca 300 jc were of c o h n nacl type co2 dominated with ch4 and n2 and are considered to be metamorphic on the basis of microthermometry and geochemistry the late to post kinematic evolution retrograde stage was characterised by a pressure drop down to 40 mpa lithostatic to hydrostatic transition and a heat input leading to temperatures z430 jc then decreasing to temperature around 170 jc fluids of the retrograde type exhibit both dilution of the c o h n nacl fluid by a low salinity meteoric water and progressive loss of volatile components 3 fluids of the retrograde type pervasively percolated through the tharsis stockwork and were responsible for the strong mineral overprint on the early deformed paragenesis all the measurable fluid inclusions f i record these late fluids there are primary fluid inclusions in q1 but they are systematically imploded due to the external overpressure generated by the variscan tectonic events although base metal distribution in the stockwork is basically the result of the

on sea ice dynamical regimes in the arctic ocean this is the publisher s final pdf the published article is copyrighted by international glaciological society and can be found at http orst library ingentaconnect com content igsoc agl 2015 00000056 00000069 art00035 token 004e105a5c5f3b3b4746527666257370507b467a404f582a2f433e402c3568263c2bc5951624c1

hydrogeochemistry of the thermal waters from the yenice geothermal field denizli basin southwestern anatolia turkey abstract the chemical and isotopic properties of thermal waters kamara and cizmeli and cold springs from the yenice geothermal field ygf in southwestern anatolia turkey are investigated in order to establish a conceptual hydrogeochemical hydrogeological model these thermal waters derive from menderes metamorphic rocks and emerge along normal faults they are commonly used for heating of greenhouses and bathing facilities discharge temperatures of thermal waters are 32 c to 57 c mean 51 c for kamara and 35 c to 68 c mean 47 c for cizmeli whereas deep groundwaters are 15 c to 20 1 c mean 17 c and shallow groundwaters are 12 to 16 c mean 15 c kamara and cizmeli thermal waters are mostly of na ca hco3 so4 type whereas deep groundwaters are ca mg hco3 and mg ca hco3 types and shallow groundwaters are mainly mg ca so4 hco3 and ca mg hco3 types in the reservoir of the geothermal system dissolution of host rock and ion exchange reactions changes thermal water types high correlation in some ionic ratios e g na vs cl k vs cl hco3 vs cl and high concentrations of some minor elements e g as sr b cl f in thermal waters likely derive from enhanced water rock interaction water samples from ygf have not reached complete chemical re equilibrium possibly as a result mixing with groundwater during upward flow geothermal reservoir temperatures are calculated as 89 102 c for kamara and 87 102 c for cizmeli fields based on the retrograde and prograde solubilities of anhydrite and chalcedony based on the isotope and chemical data a conceptual hydrogeochemical hydrogeological model of the ygf has been constructed very negative 18o and 2h isotopic ratios kamara mean of 8 43 and 56 9 respectively and cizmeli mean of 7 96 and 53 7 respectively and low tritium values

sea ice thickness measurement based on the dispersion of ice swell the dispersion of flexural waves propagating in the arctic sea ice cover is exploited in order to locally measure the ice thickness the observed dispersion for waves filtered in the 4 20 s period interval at up to 4 broad band seismometers deployed in spring 2007 near the north pole is compared to a parameterized model that accounts for a complex wavefield made of a superposition of independent plane waves with different amplitudes and back azimuth angles the parameterization that includes finding the best modeled ice thickness is performed by using the cross correlation functions between the seismometers the ice thickness is estimated to 2 5 0 2 m for the 1 km large floe the seismic stations were deployed on which is coherent with other independent measurements at this site this study thus demonstrates the feasibility of using broad band seismometers deployed on the sea ice in order to passively measure the ice thickness without requiring active sources nor human intervention

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

evaluation of groundwater hydrochemical characteristics and mixing behavior in the daying and qicun geothermal systems xinzhou basin this paper examines groundwater hydrochemical characteristics during mixing between thermal and non thermal groundwater in low to medium temperature geothermal fields a case study is made of daying and qicun geothermal fields in the xinzhou basin of shanxi province china the two geothermal fields have similar flow patterns with recharge sourced from precipitation in mountain areas heated through a deep cycle before flowing into overlying quaternary porous aquifers via fractures hydrochemical features of 60 ground and surface water samples were examined in the context of hydrogeologic information the average temperatures of the deep geothermal reservoirs are estimated to be 125 degrees c in daying field and 159 degrees c in qicun field based on na k mg geothermometry while slightly lower estimates are obtained using silica geothermometers hydrochemical features of thermal water are distinct from cold water thermal groundwater is mainly cl center dot so 4 na type with high tds while non thermal groundwater is mostly hcl 3 ca center dot mg and hco 3 ca type in the daying and qicun regions respectively hydrogeochemical processes are characterized by analyzing ion ratios in various waters higher contents of some minor elements in thermal waters such as f si b and sr are probably derived from extended water rock interaction and these elements can be regarded as indicators of flow paths and residence times mixing ratios between cold and thermal waters were estimated with cl na and b concentrations using a mass balance approach mixing between ascending thermal waters and overlying cold waters is extensive the proportion of water in the quaternary aquifer derived from a deep thermal source is lower in daying geothermal field than in qicun field 5 3 7 3 vs 6 3 49 3 mixing between thermal and non thermal groundwater has been accelerated by groundwater exploitation practices and is enhanced near faults shallow groundwater composition has also been affected by irrigation with low temperature thermal water c 2009 elsevier b v all rights reserved

new gas geothermometers for geothermal exploration calibration and application calibration of five gas geothermometers is presented three of which used co2 h2s and h2 concentrations in fumarole steam respectively the remaining two use co2h2 and h2sh2 ratios the calibration is based on the relation between gas content of drillhole discharges and measured aquifer temperatures after establishing the gas content in the aquifer gas concentrations were calculated in steam formed by adiabatic boiling of this water to atmospheric pressure to obtain the gas geothermometry functions it is shown that the concentrations of co2 h2s and h2 in geothermal reservoir waters are fixed through equilibria with mineral buffers at temperatures above 230 c epidote prehnite calcite quartz are considered to buffer co2 two buffers are involved for h2s and h2 and two functions are therefore presented for the geothermometers involving these gases for waters containing less than about 500 ppm chloride and in the range 230 300 c pyrite pyrrholite epidote prehnite seem to be involved but pyrite epidote prehnite magnetite or chlorite for waters above 300 c and waters in the range 230 300 c if containing over about 500 ppm the gas geothermometers are useful for predicting subsurface temperatures in high temperature geothermal systems they are applicable to systems in basaltic to acidic rocks and in sediments with similar composition but should be used with reservation for systems located in rocks which differ much in composition from the basaltic to acidic ones the geothermometry results may be used to obtain information on steam condensation in upflow zones or phase separation at elevated pressures measured aquifer temperatures in drillholes and gas geothermometry temperatures based on data from nearby fumaroles compare well in the five fields in iceland considered specifically for the present study as well as in several fields in other countries for which data were inspected the results of the gas geothermometers also compare well with the results of solute geothermometers and mixing models in three undrilled icelandic fields

origin evolution and geothermometry of the thermal waters in the golemezli geothermal field denizli basin sw anatolia turkey abstract the golemezli geothermal field ggf is one of the best known geothermal fields in western anatolia turkey the exploited fluids are of meteoric origin mixed with deep magmatic fluids which interacted with the metamorphic rocks of the menderes massif the geothermal fluids are channeled along quaternary faults belonging to the main normal faults system delimiting the northern side of the denizli basin and their associated transfer zones in this study hydrochemical and isotopic analyses of the thermal and cold waters allow us to determine water rock interactions fluid paths and mixing processes two groups of thermal waters have been distinguished i group 1a comprising na so4 type and ca so4 type and ii group 1b only consisting ca hco3 type waters differently two groups were recognized in the cold waters i group 2a corresponding to ca hco3 type and ii group 2b including mg hco3 type their geochemical characteristics indicate interactions with the paleozoic metamorphic rocks of the menderes massif and with the neogene lacustrine sedimentary rocks dissolution of host rock and ion exchange reactions modify thermal water composition in the reservoir of the ggf high correlation in some ionic ratios and high concentrations of some minor elements suggest an enhanced water rock interaction none of the thermal waters has been reached a complete chemical re equilibrium possibly as a result of mixing with cold water during their pathways geothermal reservoir temperatures are calculated in the range of 130 210 c for the golemezli field very negative 18o and 2h isotopic ratios are respectively between 8 37 and 8 13 and 61 09 and 59 34 for the so4 rich thermal waters and ca 8 40 and 8 32 and 57 80 and 57 41 for the hco3 rich thermal waters low tritium

strontium isotope geochemistry and its geochemical implication from hot spring waters in south korea abstract despite being a non volcanic area the southern korean peninsula has a number of hot water springs with temperatures more than 40 c most of which are commercially used for spa the hot springs are located at the fringes of the granite body rather than the center of the mesozoic granite here we report on the geochemical characteristics of the hot water springs the hot springs in the jurassic granite area are mainly of na ca hco 3 type whereas those in the cretaceous granite area are of na cl so 4 type the stable isotope composition of o and h suggests a meteoric origin of the hot spring water further the chemical components of the hot spring waters indicate that they were all derived from hot spring water rock interaction rather than through anthropogenic input the 87 sr 86 sr ratio of the hot spring waters in the jurassic granite area ranges from 0 711088 to 0 729034 and that in the cretaceous granite area ranges from 0 705652 to 0 707912 such 87 sr 86 sr ratio distribution of hot spring waters corresponds with the distribution of the initial 87 sr 86 sr ratios for the emplacement age of the jurassic and cretaceous granites in the hot spring occurrence area the 87 sr 86 sr ratios in the hot spring waters were also divided into three groups according to their geographical location eastern western and southern groups the constant 87 sr 86 sr ratio of hot spring water from one hot spring area during the last 6 years strongly suggests that the hot spring bearing aquifer system in south korea should be separated from the upper cold shallow groundwater system this indicates that the 87 sr 86 sr ratio of the hot spring waters in the granite area of south korea originates from an equilibrium because of long term water rock interaction rather than short term water rock interaction due to the input of recent meteoric water hence it may be concluded that hot spring water in the granite area may be a limited deep groundwater resource that might deplete with overuse

banded iron formations through much of precambrian time similarities between proterozoic 1 8 2 5 gyr and archean 2 5 gyr banded iron formations are probably more significant than their differences the contrasts largely reflect differences in the tectonic settings of proterozoic and archean terrains archean banded iron formations are not as thick nor laterally as extensive as the major proterozoic iron formations nevertheless some archean iron formations have strike lengths of over 150 200 km and may have been quite extensive prior to the deformation that has affected most archean terrains stratigraphic sequences in which iron formations occur are highly variable and indicate that iron formations formed in many depositional environments sedimentary textures in the iron formations are dominated either by granules and oolites or laminations including microbanding reflecting differences in their physical conditions of deposition granular and oolitic textures are abundant in only three proterozoic depositional basins and most precambrian iron forma

galapagos hot spot spreading center system 2 87sr 86 sr and large ion lithophile element variations 85 w 101 w thirty eight samples of basalts dredged from the galapagos spreading center gsc between 85 w and 101 5 w longitudes have been analyzed for k rb cs ba and sr contents as well as for 87sr 86sr ratios basalts between 85 w and 89 w segment of the gsc range from 0 7025 to 0 7028 in 87sr 86sr and those between 95 5 w and 101 5 w range from 0 7026 to 0 7027 these basalts are characterized by lree depleted patterns basalts from 89 w to 95 5 w segment having slightly lree depleted to lree enriched patterns la sm e f between 0 8 and 2 4 range from 0 7027 to 0 7031 in 87sr 86sr the longitudinal 87sr 86sr variation shows a maximum at about 92 w where the gsc is nearest to darwin island the alkali and alkaline earth elements as well as several element ratios also show maxima in their longitudinal profiles but these occur at about 91 w the apparent shift of 87sr 86sr maximum with respect to that of the trace elements may be related to differences in the degree of partial melting the highest 87sr 86sr from the gsc is only slightly lower than the highest 87sr 86sr for tholeiitic basalts from the galapagos archipelago several possible hypotheses have been examined to account for these geochemical and sr isotopic variations in the light of the presently available data the most promising explanation seems to be a binary mixing of hot spot or plume type material with the source of normal mid ocean ridge basalts and resulting rift propagation both end members seem to be heterogeneous and therefore it is at present difficult to put severe constraints on this binary mixing nevertheless the flow pattern of mantle material from the hot spot does not appear to be radial but is preferentially channeled along the 91 w and 92 5 w fracture zones toward the rift

source bearing estimation in the arctic ocean using ice mounted geophones this paper investigates the use of geophones mounted on the surface of arctic sea ice for estimating the bearing to acoustic sources in the water column the approach is based on measuring ice seismic waves for which the direction of particle motion is oriented radially outward from the source however the analysis is complicated by the fact that sea ice supports several types of seismic waves producing complex particle motion that includes significant nonradial components to suppress seismic waves with transverse particle motion seismic polarization filters are applied in conjunction with a straightforward rotational analysis computation of particle motion power as a function of angle the polarization filters require three dimensional 3d measurements of particle motion and apply theoretical phase relationships between vertical and horizontal components for the various waves types in addition the 180 ambiguity inherent in the rotational analysis can be resolved with 3d measurements by conside

hydrogeochemistry isotopes and geothermometry of ixtapan de la sal tonatico hot springs mexico the ixtapan de la sal tonatico hot springs are located in the geological setting of the trans mexican volcanic belt on the border of the morelos guerrero basin which is carbonated region with limestone and silicic rocks the temperature electrical conductivity and ph of the thermal waters are 25 7 37 2 c 9520 13 920 s cm and 5 90 6 88 respectively the hydrochemical family is nacl cl mean concentration of 2198 mg l and na mean concentration of 1396 mg l the minor and trace elements that are notable for their high concentrations are b 19 69 23 58 mg l li 6 09 8 06 mg l sr 4 80 6 18 mg l and as 0 30 1 97 mg l isotope data 18o 2h show 18o enrichment of the thermal waters which may be a result of isotopic exchange with the host rock at high temperatures although the value was very small which may be due to mixing with groundwater near the surface the water samples were oversaturated with calcite dolomite and quartz verified in the field by the presence of precipitated rocks travertines the samples were undersaturated with chalcedony silica gel cristobalite celestite and strontianite several chemical geothermometers and the results from multicomponent equilibrium suggest a reservoir temperature between 90 and 130 c meanwhile a temperature of 129 c was estimated with the cl enthalpy mixing model according to the conceptual model of the functioning of this system considering that flow is characterized by the heating of water at deep zones due to the high geothermal gradient caused by recent tectonic activity this water rises to the surface through fractures and faults as it rises thermal water mixes in different proportions with ca hco3 groundwater

high density nitrogen inclusions in barite from a giant siderite vein implications for alpine evolution of the variscan basement of western carpathians slovakia contrasting compositions and densities of fluid inclusions were revealed in siderite barite intergrowths of the dro diak polymetallic vein hosted in variscan basement of the gemeric unit central european carpathians primary two phase aqueous inclusions in siderite homogenized between 101 and 165 c total salinity ranged between 18 and 27 wt and cacl2 nacl cacl2 weight ratios were fixed at 0 1 0 3 by contrast mono and two phase aqueous inclusions in barite exhibited total salinities between 2 and 22 wt and the cacl2 nacl ratios ranged from nacl to cacl2 dominated compositions the aqueous inclusions in barite were closely associated with very high density 0 55 0 745 g cm 3 nitrogen inclusions in some cases containing up to 16 mol co2 crystallization p t conditions of siderite 175 210 c 1 2 1 7 kbar constrained by the vertical oxygen isotope gradient along the studied vein isochores of fluid inclusions and the k na exchange thermometer corresponded to minimal palaeodepths between 4 3 and 6 3 km assuming lithostatic load and average crust density of 2 75 g cm 3 maximum fluid pressure during barite crystallization attained 3 6 4 4 kbar at 200 300 c and the most dense nitrogen inclusions maintained without decrepitation the residual internal pressure of 2 2 kbar at 25 c contrasting fluid compositions increasing depths of burial 4 14 km and decreasing thermal gradients 40 15 c km 1 during initial mineralization stages of the dro diak vein reflect alpine orogenic processes rather than an incipient permian rifting suggested in previous metallogenetic models siderite crystallized at rising p t in a closed rock buffered hydrothermal system developed in the variscan basement during the north vergent cretaceous thrusting and thickening of the gemeric crustal wedge variable salinities of the barite hosted inclusions reflect a fluid mixing in open hydrothermal system and re equilibration textures lengths of decrepitation cracks proportional to fluid inclusion sizes correspond to retrograde crystallization trajectory coincidental with transpression or unroofing maximum recorded fluid pressures indicate 12 km thick pile of imbricated nappe units accumulated over the gemeric basement during the cretaceous collision

geochemical features of the geothermal fluids from the mapamyum non volcanic geothermal system western tibet china abstract mapamyum geothermal field mgf in western tibet is one of largest geothermal areas characterized by the occurrence of hydrothermal explosions on the tibetan plateau the geochemical properties of hydrothermal water in the mgf system were investigated to trace the origin of the solutes and to determine the equilibrium temperatures of the feeding reservoir the study results show that the geochemistry of hydrothermal waters in the mgf system is mainly of the na hco 3 type the chemical components of hydrothermal waters are mainly derived from the minerals in the host rocks e g k feldspar albite ca montmorillonite and mg montmorillonite the hydrothermal waters are slightly supersaturated or undersaturated with respect to aragonite calcite dolomite chalcedony and quartz saturation indices close to 0 but are highly undersaturated with respect to gypsum and anhydrite saturation indices d and 18 o data confirm that the meteoric water acts as the water source of the geothermal waters an 220 c equilibrated reservoir temperature of hydrothermal spring waters was calculated via both the na k mg ternary diagrams and the cationic chemical geothermometers the log p co 2 of hydrothermal waters in the mgf system ranges from 2 59 to 0 57 and 13 c of the total dissolved inorganic carbon ranges from 5 53 to 0 94 suggesting that the carrier co 2 in hydrothermal water are mainly of a magmatic or metamorphic co 2 origin

geochemical evaluation of thermal springs in odisha india the indian state of odisha has a number of thermal springs these thermal springs are located at eight places attri tarabalo deulajhari magarmuhan bankhol badaberena taptapani and boden and belong to mahanadi geothermal province which is an archean pre cambrian geothermal province the thermal water discharging from these springs shows moderately acidic to moderately alkaline character ph 5 05 8 93 and the temperature ranges from 28 boden to 58 c tarabalo total dissolved solids tds also shows a wide variation between 16 9 bankhol and 595 mg l deulajhari a wide variation in the chemical characteristics of the thermal waters has been observed as they are located in different geological settings based on water chemistry all the thermal springs can broadly be grouped into three water types na cl ca hco3 and na hco3 the thermal spring water from attri tarabalo and deulajhari belongs to na cl water type which is due to the circulation through granitic rocks higher concentrations of cl and f in these thermal waters further suggest limited mixing and longer residence time as compared to the other areas where ca hco3 and na hco3 water types were found anion variation diagram clearly indicates that the thermal waters from attri tarabalo and deulajhari are fast ascending and fall in the mature water field thus their chemical signatures can be used to determine the reservoir temperature however in other areas water chemistry is shaped by near surface groundwater mixing processes and thus the chemical geothermometers may not be applicable to determine the reservoir temperature no appreciable temporal variations have been observed in the water chemistry of the thermal waters

p t x constraints on the koru epithermal base metal au deposit biga peninsula nw turkey abstract the koru deposit is a typical intermediate sulfidation base metal au example of volcanic volcaniclastic hosted mineralization in the biga peninsula and northwestern turkey ore deposition was associated with the collisional and post collisional tectonics related to the closure of the tethys ocean galena baryte and quartz are main minerals accompanied by minor amounts of sphalerite pyrite chalcopyrite covellite and marcasite the homogenization temperature of fluid inclusions indicates two distinct fluid pulses one at a temperature commensurate with epithermal mineralization and boiling near boiling conditions at c 350 c with the second approximately 150 200 c lower salinity in both instances was from 11 0 to 0 2 wt nacl the d and 18o values of water in equilibrium with early quartz and fluid inclusions plot close to the magmatic water box indicating the source of the high temperature fluid was magmatic d and 18o values from early and late baryte trend towards the meteoric water line mwl but this is not due to mixing with meteoric water rather equilibration with alteration assemblages at decreasing temperature la icp ms analyses of fluid inclusions reveal high cu zn pb concentrations in the fluids despite their low salinity transported as chloride complexes the range of temperatures within the early quartz and sphalerite mineralization can be explained by pressure variations during vein and fracture opening

hydrochemical evolution and reaction simulation of travertine deposition of the lianchangping hot springs in yunnan china located in western yunnan of china the lianchangping hot springs are of so 4 hco 3 ca na type with total dissolved solids tds ranging from 3560 to 4240 mg l large amounts of travertine are deposited near the hot springs with a variety of travertine morphology including travertine terrace slope and ridge travertine is precipitating along the slope near one of the spring s thresholds chemical compositions of the hot water samples collected along travertine slope show that p co 2 p co 2 tds and contents of hco 3 and ca decrease downstream along the travertine slope due to travertine deposition the initial milliequivalent ratio of ca 2 hco 3 is greater than 1 5 before travertine precipitation and there is an increasing trend in the ratio downstream along the travertine slope high levels of sulphate are probably the result of gypsum dissolution in the sediments widespread in the lianchangping area the spring waters issuing from the land surface are slightly supersaturated with respect to calcite dolomite fluorite kaolinite halite plagioclase and carbon dioxide hydrochemical evolution of the lianchangping spring water along the slope is calculated with the phreeqc interactive 2 12 5 sets of minerals and gases reacted in appropriate amounts are recognized through reaction simulation quantitatively accounting for the variations in chemical compositions especially depositing minerals along the flow path on the travertine slope

edge wave observation using remote seismoacoustic sensing of ice events in the arctic as part of the office of naval research sea ice mechanics initiative a real time monitoring and processing program for acoustic emission from ice fracture and ridge building events was established a wide aperture horizontal hydrophone array was used in combination with a vertical line array to record the acoustic signals which were then passed through a focused beam former for real time generation of ice seismicity maps a number of rapidly deployable geophone arrays were used in active zones to measure the acoustic emissions in the near field for detailed seismic event analysis during one such deployment a highly regular transient arrival structure was recorded on all sensors located near a major lead with a transient appearing every 5 s these data have been processed using frequency wavenumber analysis to show that the transients correspond to edge waves propagating forth and back along the edges of the lead with the probable source being a stick slip mechanical phenomenon toward the ends of the lead

hydrogeochemical outline of thermal waters and geothermometry applications in anatolia turkey abstract the chemical compositions of a total of 120 thermal water samples from four different tectonically distinct regions central north east and west anatolia of turkey are presented and assessed in terms of geothermal energy potential of each region through the use of chemical geothermometers na ca hco3 type waters are the dominant water types in all the regions except that na cl type waters are typical for the coastal areas of west anatolia and for a few inland areas of west and central anatolia where deep water circulation exists the discharge temperature of the springs ranges up to 100 c and the bottom hole temperatures in drilled wells up to 232 c geothermometry applications yield reservoir temperatures of about 125 c for central anatolia 110 c for north anatolia 136 c for east anatolia and 251 c for west anatolia the latter agreeing with some of the bottom hole temperatures measured in drilled wells the results reveal that the highest geothermal energy potential in turkey is associated with the west anatolian extensional tectonics which provides a regional deep seated heat source and a widespread graben system allowing deep circulation of waters the north anatolian region bounded to the south by the dextral north anatolian fault along which most of the geothermal sites are located has the lowest energy potential probably due to the restriction of the heat source to local magmatic activities confined to pull apart basins the east anatolian region undergoing contemporary compression and the central anatolian region where the compressional regime in the east is converted to the extensional regime in the west have moderate energy potential although the recently active volcanoes suggest the presence at depth of still cooling magma chambers that are potential heat sources the lack of well developed fault systems is probably responsible for the comparatively low energy potential of these regions almost all the thermal waters of turkey are saturated with respect to calcite and hence have a significant calcite scaling potential which is particularly high for west anatolian waters

geochemistry and sedimentology of a facies transition from microbanded to granular iron formation in the early proterozoic transvaal supergroup south africa abstract a transition from microbanded kuruman to granular griquatown iron formation is described in terms of sedimentological petrographic and geochemical characteristics major minor trace and rare earth elements as well as whole rock carbon and oxygen isotopic compositions transitions between microbanded and granular iron formation are uncommon in the global stratigraphic record with microbanding absent from most known granular iron formations the kuruman griquatown transition zone differs from other granular iron formation sequences in being non oolitic i e peloidal and magnetite rich instead of hematite rich it is concluded that the coarsening upward microbanded granular iron formation units in the kuruman griquatown sequence represent upward shallowing storm dominated deposits that is primary microbanded relatively deep water fair weather deposits having been intermittently reworked by storm wave action form wavy sharp based graded and poorly sorted irregular interbeds of granular iron formation this is in contrast to typical hematitic oolitic iron formation units which represent true shoal deposits geochemical results strongly support the storm reworking hypothesis microbanded and granular iron formation beds have similar ree patterns with negative ce anomalies and depletion in light ree reflecting deposits in a marine setting below the zone of shallow surface water positive eu anomalies in the ree patterns suggest admixture of a hydrothermal component of the ocean water carbonates in the iron formation are depleted in 13c indicating involvement of organic matter during diagenetic alteration of the iron formations there are also indications that total dissolved carbon dioxide in deeper water was more depleted in 13c than in shallower water deposition of the iron formations was sporadically interrupted by influx of tuffaceous material now represented by centimeter thick shard and lapilli bearing stilpnomelane lutite beds these beds differ chemically from the iron formations in being enriched in elements such as al sc y zr nb hf ta th u and the lanthanides and displaying ree patterns with strong negative eu and slight positive ce anomalies the composition of the parent magma of the volcanics remains uncertain because of probable post depositional alteration of the volcanic glass however it was most probably of intermediate to acidic composition as concluded from the widespread distribution of the ash beds typical of plinian type deposits chemical variations in the minor trace and ree compositions of the iron formations are closely correlated with the amounts of admixed volcanic ash material most of the iron formations appear chemically very uncontaminated being highly depleted in all minor trace and ree and organic carbon contents the iron formations were therefore most probably deposited as a chemical precipitate on a submerged shallow cratonic platform with volcanic ash as the only exogenic material sporadically reaching the depository

groundwater evolution in the continental intercalaire aquifer of southern algeria and tunisia trace element and isotopic indicators abstract the geochemical processes taking place along an 800 km flow line in the non carbonate continental intercalaire aquifer ci aquifer in north africa are described using chemical major and trace element and isotopic indicators the aquifer is hydraulically continuous from the atlas mountains in algeria to the chotts of tunisia and the geochemical evidence corroborates this the highest discharge temperature is 73 c but silica geothermometry indicates a maximum temperature of 94 c at depth chloride concentrations increase from 200 to 800 mg l 1 and the br cl ratios confirm the dissolution of non marine evaporites or interstitial waters as the main source of salinity fluoride concentrations are low and are likely to be derived from rainfall recording oscillations in source radiocarbon ages except near outcrop are at or near detection limits and the 18o and 2h values indicate a cooler recharge regime with rainfall having lower primary evaporation than today this is shown by the fact that mean isotope ratios of ci waters are around 3 lighter than the present day weighted mean value for rain major ion ratios and most trace elements indicate that despite the complex structure and stratigraphy uniform evolution with continuous water rock interaction takes place along the flow lines which are only disturbed near the tunisian chotts by groundwater converging from additional flow lines the ageing of the water can also be followed by the smooth increase in several indicator elements such as li k and mn which are least affected by solubility controls similarly the influence of marine facies in the tunisian sector may be recognised by the changing mg ca and higher br cl as well as trace element indicators the groundwaters are oxidising up to 300 km from outcrop dissolved o2 has persisted for at least 20 ka and within this zone the concentrations of several elements forming oxy anions such as u and cr increase and no3 remains conservative beyond 300 km from outcrop the groundwaters are reducing and contain high fe concentrations the basin contains huge reserves of fresh brackish waters but these need careful development due to the limiting high salinity and scaling tendency resulting from the high temperatures and mineral super saturation caused during abstraction as well as high concentrations of some harmful elements such as cr in the oxidising section

geochemical constraints for the origin of thermal waters from western turkey the combined chemical composition b and sr isotopes and the basic geologic setting of geothermal systems from the menderes massif in western turkey have been investigated to evaluate the origin of the dissolved constituents and mechanisms of water rock interaction four types of thermal water are present 1 a na cl of marine origin 2 a na hco3 type with high co2 content that is associated with metamorphic rocks of the menderes massif 3 a na so4 type that is also associated with metamorphic rocks of the menderes massif with h2s addition and 4 a ca mg hco3 so4 type that results from interactions with carbonate rocks at shallow depths the na cl waters are further subdivided based on br cl ratios water from the cumali seferihisar and bodrum karaada systems are deep circulated seawater br cl sea water whereas water from canakkale tuzla br cl sea water are from dissolution of messinian evaporites good correlations between different dissolved salts and temperature indicate that the chemical composition of the thermal waters from non marine geothermal systems is controlled by 1 temperature dependent water rock interactions 2 intensification of reactions due to high dissolved co2 and possibly hcl gasses and 3 mixing with overlying cold groundwater all of the thermal water is enriched in b the b isotopic composition 11b 2 3 to 18 7 n 6 can indicate either leaching of b from the rocks or b oh 3 degassing flux from deep sources the large ranges in b concentrations in different rock types as well as in thermal waters from different systems suggest the water rock mechanism 87sr 86sr ratios of the thermal water are used to differentiate between solutes that have interacted with metamorphic rocks 87sr 86sr ratio as high as 0 719479 and carbonate rocks low 87sr 86sr ratio of 0 707864

hydrochemical and hydrological processes in the different landscape zones of alpine cold region in china investigation of water sources and flow pathways is crucial to understand and evaluate the characteristics of surface water and groundwater systems this article aims to identify the hydrochemical and hydrological processes in different landscape zones based on hydrochemical analyses of various samples including samples from glacier snow frozen soil meltwater surface water groundwater and precipitation in the alpine cold region of china hydrochemical tracers indicated that chemical compositions are characterized by the ca hco3 type in the glacier snow zone the mg ca so4 type in the alpine cold desert zone the ca hco3 so4 type in the marsh meadow zone the ca mg hco3 type in the alpine shrub zone and the ca na so4 type in the mountain grassland zone an end member mixing model was used for hydrograph separation the results showed that the mafengou river in the wet season was recharged by groundwater in the alpine cold desert and alpine shrub zones 67 surface runoff in the glacier snow zone 11 surface runoff in the alpine cold desert zone 8 thawed water from frozen soil in the marsh meadow and mountain grassland zones 9 and direct precipitation on the river channel 5 this study suggests that precipitation from the whole catchment yielded little direct surface runoff precipitation was mostly transformed into groundwater or interflow and was then concentrated into the river channel this study provides a scientific basis for evaluation and management of water resources in the basin

origin of the duvertepe kaolin alunite deposits in simav graben turkey timing and styles of hydrothermal mineralization abstract the duvertepe district located on the western end of the simav graben is the largest known fossil hydrothermal kaolin deposit in turkey active hot springs occur to the north of simav city eynal citgol nasa and geothermal fields occur to the west of the graben hisaralan kaolin in the duvertepe district formed at the expense of miocene rhyolites rhyodacites and tuffs emplaced in a tectonically active system undergoing n s extension upward fan shaped deposits of silicification and kaolin are found along fault zones and define areas of enhanced kaolinization silica sinters located above the kaolin zones suggest that hydrothermal fluids followed the fracture systems and mark outflow of geothermal waters fractured volcanic rocks rich in glass shards bear sufficient porosity and permeability for hydrothermal circulation two mineral facies kaolinite and alunite dominate the deposits which respectively include 1 kaolinite alunite quartz and 2 alunite opal ct quartz halloysite kaolinite crystals are well formed hexagonal vermiform habits and alunite crystals are idiomorphic rhombohedral forms needle and tubular shaped halloysites are common in the alunite facies the 34 s values for alunite range from 1 55 to 6 18 kaolinites have d ranging from 49 0 to 94 3 and the 18 o values range from 5 8 to 14 8 calculated formation temperatures of kaolin mineralization using 18 o values suggest that hydrothermal alteration occurred in the range of 38 to 129 c independent k ar and 40 ar 39 ar ages of alunite are concordant and indicate that alteration occurred from 20 1 to 20 6 ma in the southern part of the graben and 17 3 to 19 2 ma in the northern part these results suggest that metasomatism by steam heated hydrothermal fluids sourced by rhyolitic magma is responsible for the duvertepe kaolin and alunite deposit origins

hydrogeochemical characteristics and formation of the hot springs occurring in the plunging ends of an anticline in chongqing eastern sichuan basin china hot springs occurring in two plunging ends of a very long and narrow anticline is unique this study focuses on the hydrogeochemical characteristics and formation of the anticline controlled thermal groundwater which may provide a perspective for geothermal resources potential the low to middle temperature thermal groundwater of the taozidang anticline in the sichuan basin china was examined to estimate the temperature of the deep reservoir and identify the main hydrogeochemical processes affecting the composition of hot water during circulation and evolution the occurrences of thermal groundwater of these springs strongly controlled by anticline are in the two plunging ends of the anticline and differ from that of the more common deep fault circulation controlled by faults or by faults and anticlines incongruent dissolution of the gypsum or anhydrite of the lower triassic jialingjiang and middle triassic leikoupo groups is affected by the anticline structures and results in hot water of so4 ca type meteoric water infiltrates through the karst channels and fissures at the outcropping area of carbonates to feed the groundwater part of the groundwater flows to depth and circulate along the two flanks of the anticline after heated it issues in the form of hot springs or wells in the plunging ends of the anticline another part of the groundwater undergoing a shallow circulation forms the normal temperature spring near the hot springs this study of the anticline controlled thermal groundwater is important for exploitation and utilization of geothermal energy tourism and provides a perspective for the anticline controlled geothermal resources potential

evolution of hydrothermal waters at mount st helens washington usa abstract hydrothermal water samples at mount st helens collected between 1985 and 1989 and in 1994 are used to identify water types and describe their evolution through time two types of low temperature hydrothermal systems are associated with the 1980 eruptions and were initiated soon after emplacement of shallow magma and pyroclastic flows the loowit hot spring system is located in the breach zone and is associated with the magma conduit and nearby avalanche deposits whereas the pumice plain pp system is associated with pyroclastic flows and avalanche deposits 3 to 5 km north of the volcano the pp waters first discharged at the surface in 1981 whereas the loowit waters began to issue at the surface in 1983 d 18o and 3h indicated all thermal waters are dominantly derived from post 1980 recharge fluids flow through and are restricted to the shallow 1980 avalanche and pyroclastic deposits all water cooled with time up to 43 c on the pp and up to 20 c in loowit in 5 years and chemical compositions have changed rapidly all waters have highly variable and unreliable geothermometer temperatures with maximum indicated temperatures

interpretation of a few ice event transients this article discusses some of the observables important to the study of sound radiated into the water by ice fracturing events such studies are important in order to understand the mechanisms of arctic ocean ambient noise generation theoretical work for a homogeneous ice plate indicates that there are three important paths of elastic wave propagation over which energy travels away from an ice event source these are the flexural wave in the ice the longitudinal wave in the ice and the acoustic wave in the water each has a distinctive propagation speed attenuation and associated pressure field in the water the experimental work consisting of the interpretation of four ice events supports the theoretical description in each case the event is located and the contributing wave paths identified in all cases the acoustic wave dominates the work also demonstrates how event analysis can be used to determine ice properties

processes controlling the distribution of boron and chlorine in natural waters in iceland abstract the concentrations of b and cl in natural waters in iceland lie in the range 0 001 10 and 1 20 000 ppm respectively lowest concentrations occur in surface and groundwaters in the central highlands highest cl concentrations are found in high temperature waters on the reykjanes peninsula and highest b concentrations in well waters from high temperature geothermal systems in the axial zones of the active volcanic belts the b and cl contents of icelandic basalts are 0 1 6 6 and 75 750 ppm respectively these large variations are considered to result from variable degassing during consolidation as well as concentration variations in the initial magma tholeftes are lowest in both elements av 1 2 ppm b and 170 ppm ci transitional basalts intermediate av 2 1 ppm b and 240 ppm ci and alkali basalts highest av 3 8 ppm b and 340 ppm cl cl b ratios in tholeiites are most often within 25 50 but somewhat lower in alkali basalts most geothermal waters contain b and cl within 0 05 1 and 10 100 ppm respectively these rather low values are attributed to the low content of b and cl in the basaltic rock the b and cl distribution in the icelandic natural waters indicate that these elements act as essentially incompatible their sources of supply include 1 the atmosphere seawater spray and aerosols 2 the rock with which the water interacts 3 seawater groundwater and 4 magma intrusions in surface water and nonthermal groundwater the dominant source of supply of cl is seawater spray and aerosols but the soil and rock contribute often significantly to the b in these waters their cl b ratio is similar to that of seawater 1330 or somewhat lower boron and cl concentrations generally increase with water temperature warm waters cl b ratios intermediate between those of seawater and basalt with increasing temperature this ratio decreases and gradually approaches that of the rock some high temperature geothermal waters have as low cl b ratios as 1 and b concentrations as high as 10 ppm the cause is either b degassing of the magmatic intrusive heat source or phase separation in the producing aquifer some low temperature waters

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

environmental isotopic and hydrochemical characteristics of groundwater systems in daying and qicun geothermal fields xinzhou basin shanxi china the conceptual hydrogeological model of the low to medium temperature daying and qicun geothermal fields has been proposed based on hydrochemical characteristics and isotopic compositions the two geothermal fields are located in the xinzhou basin of shanxi china and exhibit similarities in their broad scale flow patterns geothermal water is derived from the regional groundwater flow system of the basin and is characterized by cl center dot so 4 na type thermal water is hydrochemically distinct from cold groundwater having higher total dissolved solids tds 0 8 g l and sr contents but relatively low ca mg and hco 3 contents most shallow groundwater belongs to local flow systems which are subject to evaporation and mixing with irrigation returns the groundwater residence times estimated by tritium and 14 c activities indicate that deep non thermal groundwater 130 160 m in the daying region range from modern post 1950s in the piedmont area to more than 9 4 ka bp before present in the downriver area and imply that this water belong to an intermediate flow system thermal water in the two geothermal fields contains no detectable active 14 c indicating long residence times 50 ka consistent with this water being part of a large regional flow system the mean recharge elevation estimated by using the obtained relationship altitude m 23 8 x delta 2 h parts per thousand 121 3 is 1980 and 1880 m for the daying and qicun geothermal fields respectively the annual infiltration rates in the daying and qicun geothermal fields can be estimated to be 9029 x 10 3 and 4107 x 10 3 m 3 a respectively the variable 86 sr 87 sr values in the thermal and non thermal groundwater in the two fields reflect different lithologies encountered along the flow path s and possibly different extents of water rock interaction based on the analysis of groundwater flow systems in the two geothermal fields hydrogeochemical inverse modelling was performed to indicate the possible water rock interaction processes that occur under different scenarios copyright c 2010 john wiley sons ltd