continental scale salt tectonics on mars and the origin of valles marineris and associated outflow channels a synthesis of deformation patterns within and around the thaumasia plateau mars points to a new interpretation for regional deformation and the origin of valles marineris and associated outflow channels the morphology of the thaumasia plateau is typical of thin skinned deformation akin to a mega slide in which extensional deformation in syria planum and noctis labyrinthus connects via lateral zones of transtension and strike slip claritas fossae and valles marineris to a broad zone of compressional uplift and shortening defined by truncated craters and thrust faults along the coprates rise and thaumasia highlands however the low regional slope 1 results in gravitational body forces that are too small to deform the basaltic lava flows conventionally thought to compose the flanks of the tharsis volcanic province instead we conclude that geothermal heating and topographic loading of extensive buried deposits of salts and or mixtures of salts ice and basaltic debris would allow for weak detachments and large scale gravity spreading we propose that the generally linear chasmata of valles marineris reflect extension collapse and excavation along fractures radial to tharsis either forming or reactivated as part of one lateral margin of the thaumasia gravity spreading system the other dextral lateral margin is a massive splay of extensional faults forming the claritas fossae which resembles a trailing extensional imbricate fan the compressional mountain belt defined by the coprates rise and thaumasia highlands forms the toe of the mega slide topographic observations and previous structural analyses reveal evidence for a failed volcanic plume below syria planum that could have provided further thermal energy and topographic potential for initiating regional deformation either intrusively through inflation or extrusively through lava flow and or ash fall emplacement higher heat flow during noachian time or geothermal heating due to burial by tharsis derived volcanic rocks would have contributed to flow of salt deposits as well as formation of groundwater from melting ice and dewatering of hydrous salts we further propose that connection of overpressured groundwater from aquifers near the base of the detachment through the cryosphere to the martian surface created the outflow channels of echus coprates and juventae chasmata at relatively uniform source elevations along the northern margin of the mega slide where regional groundwater flow would have been directed toward the surface our hypothesis provides a unifying framework to explain perplexing relationships between the rise of the tharsis volcanic province deformation of the thaumasia plateau and the formation of valles marineris and associated outflow channels

a contribution of co2 released from mineral springs into overall volume of annual co2 emissions in the slovak republic complex geological and tectonic structure of the western carpathians within the slovak territory has conditioned generation of abundant mineral springs 1782 with various levels of mineralization and chemical types many of them possess a high content of co2 and therefore they may be considered as permanent point sources of co2 they are a part of natural analogues due to this fact an approximate estimation of overall annual volume of co2 has been carried out however such seemingly simple calculation requests an introduction of necessary corrections professional estimates and some limitations based on knowledge and practical experience from a long term monitoring the final result of this process of all considered sources provided volume of around 4 mt of co2 year 1 this amount represents annual co2 emission of standard thermal power plant ca 500 mw and creates practically 10 of the annual slovak co2 production it means that the volume of co2 produced from mineral springs is not a negligible item and may create remarkable share of aggregated emissions in countries of similar geological and hydrogeological structure that is why it should be included in the emission evaluation of the countries concerned

assessing the potential consequences of co2 leakage to freshwater resources a batch reaction experiment towards an isotopic tracing tool abstract the assessment of the environmental impacts of co 2 geological storage requires the investigation of potential co 2 leakages into fresh groundwater particularly with respect to protected groundwater resources the geochemical processes and perturbations associated with a co 2 leak into fresh groundwater could alter groundwater quality indeed some of the reacting minerals may contain hazardous constituents which might be released into groundwater since the geochemical reactions may occult direct evidence of intruding co 2 it is necessary to characterize these processes and identify possible indirect indicators for monitoring co 2 intrusion the present study focuses on open questions can changes in water quality provide evidence of co 2 leakage which parameters can be used to assess impact on freshwater aquifers what is the time scale of water chemistry degradation in the presence of co 2 the results of an experimental approach allow selecting pertinent isotope tracers as possible indirect indicators of co 2 presence opening the way to devise an isotopic tracing tool the study area is located in the paris basin france which contains deep saline formations identified as targets by french national programs for co 2 geological storage the study focuses on the multi layered albian fresh water aquifer confined in the central part of the paris basin a major strategic potable groundwater overlying the potential co 2 storage formations an experimental approach batch reactors was carried out in order to better understand the rock water co 2 interactions with two main objectives the first was to assess the evolution of the formation water chemistry and mineralogy of the solid phase over time during the interaction the second concerned the design of an isotopic monitoring program for freshwater resources potentially affected by co 2 leakage the main focus was to select suitable environmental isotope tracers to track water rock interaction associated with small quantities of co 2 leaking into freshwater aquifers in order to improve knowledge on the albian aquifer and to provide representative samples for the experiments solid and fluid sampling campaigns were performed throughout the paris basin albian groundwater is anoxic with high concentrations of fe a ph around 7 and a mineral content of 0 3 g l 1 macroscopic and microscopic solid analyses showed a quartz rich sand with the presence of illite smectite microcline apatite and glauconite a water mineral co 2 interaction batch experiment was used to investigate the geochemical evolution of the groundwater and the potential release of hazardous trace elements it was complemented by a multi isotope approach including 13 c dic and 87 sr 86 sr here the evolution of the concentrations of major and trace elements and isotopic ratios over batch durations from 1 day to 1 month are discussed three types of ion behavior are observed type i features ca sio 2 hco 3 f po 4 na al b co k li mg mn ni pb sr zn which increased after initial co 2 influx type ii comprises be and fe declining at the start of co 2 injection then type iii groups element with no variation during the experiments like cl and so 4 the results of the multi isotope approach show significant changes in isotopic ratios with time the contribution of isotope and chemical data helps in understanding geochemical processes involved in the system the isotopic systems used in this study are potential indirect indicators of co 2 water rock interaction and could serve as monitoring tools of co 2 leakage into an aquifer overlying deep saline formations used for c sequestration and storage

high heat flux on ancient mars evidence from rift flank uplift at coracis fossae 1 we have identified flexural uplift at the flanks of the coracis fossae rift valley modeling the topography the elastic thickness is constrained to 10 3 12 5 km the corresponding mechanical thickness and thermal gradient are 15 19 km and 27 33 k km 1 respectively the time of rifting is dated by evaluating the crater size frequency distribution of key surface units related to the rifting thus the heat flux between 3 5 and 3 9 ga is calculated to be 54 66 mw m 2 furthermore the stresses supported by the rift bounding faults are estimated to be below 5 mpa we speculate that this weakness may be connected to the presence of water below the surface

three dimensional normal faulting models of the valles marineris mars and geodynamic implications inversion of martian topography using a three dimensional boundary element model permits revised estimates of fault dip angle depth of faulting paleogeothermal gradient and extensional strain in the valles marineris region the major normal faults dip at 40 55 to depths of 60 75 km with comparatively small footwall uplifts 500 m for throws to 10 km implying that paleogeothermal gradients during faulting were 10 k km 1 or less assuming relatively rapid strain rates appropriate to the extending martian crust accumulation of dip slip offsets along the main normal faults likely was associated with anticlinal flexure and deformation of preexisting strata within the troughs the magnitudes of the predicted vertical and horizontal displacements outside the troughs as well as extensional strains are spatially variable depending on both cross and along strike position relative to the troughs the predicted displacements and strains attain maximum values at the troughs and decay to background values at cross strike distances of 250 km corresponding to 3 4 times the depth of faulting with an average province wide strain of 4 15 by implication the aggregate strain field surrounding tharsis is a highly variable spatial and temporal composite of the inhomogeneous strain fields each associated and scaling in size with an individual graben from the smallest structures through the largest valles marineris troughs

radar and photoclinometric studies of wrinkle ridges on mars earth based radar altimetry and image derived photoclinometric profiles were analyzed to examine both the long and short wavelength topography associated with wrinkle ridges on mars photoclinometrically derived elevation data across wrinkle ridges were evaluated to determine the sensitivity of profiles to two empirical photoclinometric parameters the horizontal digital number hdn and the scattered light value slv the photoclinometric profiles are extremely sensitive to small variations in hdn the sense of slope of a profile can be completely reversed over a range in hdn of as little as 1 comparably small variations in the slv have relatively minor effects on the photoclinometrically derived elevations the existence of elevation offsets from one side of the ridge to the other reported in previous photoclinometric studies of martian wrinkles were not confirmed through photoclinometry in addition no evidence of elevation offsets were found in earth based radar altimetry profiles across wrinkle ridges in order to more accurately model wrinkle ridge topography we controlled photoclinometrically derived elevations with long wavelength topography obtained from the radar altimetry the results of this study do not support kinematic models for the origin of planetary wrinkle ridges that involve deeply rooted thrust faults which separate crustal blocks at different elevations a kinematic model involving buckling of shallow crustal layers into concentric folds that close leading to the development of thrust faults is consistent with wrinkle ridge morphology and terrestrial analogs recent geophysical studies of terrestrial analogs and the influence of shallow subsurface structures particularly buried craters on the localization of many wrinkle ridges on mars suggest that thrust faults associated with the ridges are confined to the ridged plains material and do not extend into the lithosphere

weakening of rock salt by water during long term creep the rheological properties of rock salt are of fundamental importance in predicting the long term evolution of salt based radioactive waste repositories and strategic storage caverns and in modelling the formation of salt diapirs and associated oil traps1 2 the short term high stress rheology of rock salt is well known from laboratory experiments however extrapolation to appropriately low stresses fails to predict the rapid flow seen in certain natural structures furthermore experiments have failed to reproduce the recrystallized microstructure of naturally deformed salt here we report experiments indicating that the above discrepancies can be explained by taking into account the influence of trace amounts of brine trace brine is always present in natural salt but sometimes escapes during experiments our tests on dry dilated salt show more or less conventional dislocation creep behaviour but brine bearing samples show marked weakening at low strain rates this is associated with dynamic recrystallization and a change of deformation mechanism to solution transfer creep because natural rock salt always contains some brine these results cast substantial doubt on the validity of presently accepted dislocation creep laws for predicting the long term rheological behaviour of salt in nature

hydrogeochemical modeling of a thermal system and lessons learned for co2 geologic storage abstract geological storage of carbon dioxide is presently considered to be one of the main strategies to mitigate the impact of the emissions of this gas on global warming among the various alternatives considered for co 2 geological storage one of the main geological candidates for hosting injected co 2 in the long term are deep porous reservoir rock formations saturated with brackish or saline solutions although valuable information on the expected hydrogeochemical processes involved in the co 2 storage in such deep saline aquifers can be obtained in laboratory or modeling studies the only direct source of information about the long term behavior of geological storages for co 2 in deep aquifers is natural analogues in this work a classical and simple geochemical methodology is successfully applied to the study of the features and hydrogeochemical processes determining the evolution of a spanish thermal system the alhama jaraba complex which can be considered as a natural analogue for deep geological co 2 storage in carbonate rocks the geology structure depth and hydrogeochemistry of the alhama jaraba thermal system are very similar to the expected features of a potential co 2 reservoir in carbonate materials the processes determining the hydrogeochemical evolution in the alhama jaraba thermal system have been successfully identified and quantified with the assistance of ion ion plots speciation solubility calculations and mass balance calculations furthermore the feasibility of the proposed conceptual hydrogeochemical model for this system has been verified by using reaction path calculations mass balance calculation results have indicated that the observed hydrogeochemical evolution between springs is mainly due to halite dissolution and dedolomitization triggered by gypsum or anhydrite dissolution co 2 g mass transfer has been estimated to be negligible which suggests that the main processes responsible for the variation in the tic and the co 2 g pressure during deep circulation are dissolution and precipitation reactions for carbonate minerals all the processes identified in the alhama jaraba thermal system are relevant for the long term evolution of a deep co 2 storage site hosted by carbonate rocks as shown in this study the application of classical geochemical tools provides an excellent starting point for understanding the behavior of prospective storage systems moreover the existence of dedolomitization is very relevant for the hydraulic properties of carbonate aquifers potentially used for co 2 geological storage because of the effects on porosity and therefore permeability during the long term evolution of such systems furthermore dedolomitization may represent a mechanism of mineral trapping for co 2 sequestration under certain conditions

new models for the origin of valles marineris closed depressions current models for the formation of the abundant large closed depressions of valles marineris have serious shortcomings purely tectonic mechanisms are inconsistent with the morphology of many depressions and removal of large quantities of ground ice from the canyon walls is inconsistent with the observed strength of the walls accordingly we offer some alternatives one possibility involves decay of ice rich bodies occupying partially sediment choked ancient graben that predated the overlying cratered and ridged plains other possibilities involve the removal of massive equatorial carbonate deposits storing much of the planet s co2 inventory generated during greenhouse conditions on early mars solution by carbonic acid derived from the atmosphere analogous to terrestrial karst requires extensive recycling of the available water supply solution by various groundwater acids possibly derived from the tharsis magmas requires less water especially if only the smaller closed depressions are due to carbonate decay alternatively volume loss due to decarbonation of carbonate during early high heat flow or a later tharsis related heat pulse can produce extensive collapse especially if the carbonates have high silica content

erosional valleys in the thaumasia region of mars hydrothermal and seismic origins analysis of erosional valleys geologic materials and features and topography through time in the thaumasia region of mars using co registered digital spatial data sets reveals significant associations that relate to valley origin valleys tend to originate 1 on noachian to early hesperian stages 1 and 2 large volcanoes 2 within 50 100 km of stages 1 and 2 rift systems and 3 within 100 km of noachian stage 1 impact craters 50 km in diameter these geologic preferences explain observations of higher valley source densities vsds in areas of higher elevations and regional slopes 1 because the volcanoes rifts and craters form high steep topography or occur in terrain of high relief other stage 1 and stage 2 high steep terrains however do not show high vsds the tendency for valleys to concentrate near geologic features and the overall low drainage densities in thaumasia compared to terrestrial surfaces rule out widespread precipitation as a major factor in valley formation as is proposed in wann wet climate scenarios except perhaps during the early noachian for which much of the geologic record has been obliterated instead volcanoes and rifts may indicate the presence of shallow crustal intrusions that could lead to local hydrothermal circulation melting of ground ice and snow and groundwater sapping however impact crater melt would provide a heat source at the surface that might drive away water fonning valleys in the process post stage 1 craters mostly have low nearby vsds which for valleys incised in older rocks suggests burial by ejecta and for younger valleys may indicate desiccation of near surface water and deepening of the cryosphere later hesperian and amazonian stages 3 and 4 valleys originate within 100 200 km of three young large impact craters and near rifts systems at warrego valles and the southern part of coprates rise these valleys likely developed when the cryosphere was a couple kilometers or more thick inhibiting valley development by hydrothermal circulation however eruption of groundwater may have occurred from impact induced fracturing and lateral and perhaps minor upward transport of water due to seismic pumping the two smaller craters formed along the plateau margin where the highest potential hydraulic head would occur in aquifers beneath the plateau in the case of the larger crater lowell 200 km in diameter potential aquifers would likely be at depths of kilometers below the cryosphere seismic energy generated by the lowell impactor would have been much greater pumping both groundwater and perhaps fluidized slurry to the surface from beneath the cryosphere to form the young valleys and flow deposit along the margin of thaumasia tectonic pressurization of groundwater also may have contributed to valley formation dissection of rim materials of the argyre impact may relate to tectonic activity and the unconsolidated state of basin ejecta

influence of pore fluid salinity on pressure solution creep in gypsum abstract the uniaxial compaction creep behaviour of wet granular gypsum is investigated under chemically closed drained conditions known to favour pressure solution the experiments were performed using applied stresses of 1 to 4 mpa and grain sizes in the range 50 to 280 m at room temperature the tests were carried out using saline pore fluids with a nacl concentration of 0 01 to 6 m saturated with respect to the unstressed gypsum starting material since gypsum is almost always associated with other evaporite minerals such as halite pore fluid compositions in gypsum will generally be highly saline data on the effect of pore fluid salinity on pressure solution in gypsum are thus directly relevant to the behaviour of gypsum in geological situations the results obtained in terms of mechanical behaviour and microstructures developed are in good agreement with the results obtained in previous experiments performed using nacl free pore fluids however the absolute creep rates obtained here are up to 50 times faster than in the nacl free tests comparison with theoretical models for pressure solution creep and crystal growth data reveals that diffusion is unlikely to be the rate controlling mechanism of pressure solution in the present experiments since the growth rate of gypsum increases with nutrient salinity the observed effect of nacl on pressure solution is consistent with the possibility of rate control by the precipitation reaction however the absolute creep rates observed are one to two orders of magnitude slower than creep rates predicted by a precipitation rate limited model so that the detailed mechanism remains unclear

decollement tectonics in the jura forelandfold and thrust belt abstract interpretation of more than 1500 km of industry seismic reflection lines from theswiss and french jura mountains and the western swiss molasse basin demonstrates that themesozoic and cenozoic cover of the jura fold and thrust belt has been deformed over a veryweak basal decollement and displaced for many kilometers toward the nw and that thebasement is not involved a depth to the basement map derived from depth conversion of theseismic lines shows a rather smooth flat basement dipping 1 3 to the s se the low amplitudebroad folds of the molasse basin and the external plateau jura are controlled by evaporitepillows or anticlines of middle triassic age the high amplitude folds of the haute chaine jura however are related to nw or se vergent thrusts with at least kilometric dipslip displacementthat has doubled the entire jurassic sequence the plateau jura evaporite related folds located in the foreland are interpreted as early stage buckle folds with further deformation afault ramp nucleates and develops into thrust related folds as observed in the haute chaine thus within the fold and thrust belt deformation increases toward the hinterland in the molassebasin however low amplitude folds represent an early deformation stage which could notdevelop further owing to the load of the overlying thick tertiary clastic wedge

strike slip faulting of ridged plains near valles marineris mars the surface of mars shows abundant evidence of extensional and contractional deformation in the form of normal faults grabens and wrinkle ridges 1 3 in contrast strike slip faults have been considered to be extremely rare or absent on mars4 5 this view is based on the lack of significant lateral offset of pre existing markers such as craters across suspected faults thus mars is believed to have evolved without plate tectonics or other large scale lateral motions of the lithosphere6 however careful study of viking orbiter images is revealing that strike slip faults may be present on mars7 here i identify and document several well preserved examples of martian strike slip faults and examine their relationships to wrinkle ridges the strike slip faulting predates or overlaps periods of wrinkle ridge growth south east of valles marineris and some wrinkle ridges may have nucleated and grown as a result of strike slip displacements along the echelon fault arrays lateral displacements of several kilometres inferred along these arrays may be related to tectonism in tharsis

carbon dioxide earth degassing and seismogenesis in central and southern italy 1 we present the first regional map of co2 earth degassing from a large area most of central and south italy derived from the carbon of deep provenance dissolved in the main springs of the region the investigation shows that a globally significant amount of deeply derived co2 10 of the estimated global co2 emitted from subaerial volcanoes is released by two large areas located in western italy the anomalous flux of co2 suddenly disappears in the apennine in correspondence to a narrow band where most of seismicity concentrates here at depth the gas accumulates in crustal traps generating co2 overpressurized reservoirs which induce seismicity

halide systematics in interstitial waters of ocean drilling sediment cores abstract the distribution of dissolved halides cl br i in interstitial waters of deep drill holes in the ocean is discussed for a number of environments hemi pelagic sediments hydrate containing sediments sediments affected by halide brines and also in hydrothermal environments the importance of the diagenesis of organic c in the production of i and br is discussed with reference to the observations of dissolved so 4 2 and nh 4 in the pore fluids more importantly in the zone of methano genesis below the so 4 2 reduction zone and usually associated with high organic c accumulation rates increases in i and br are of importance and usually are much higher than the increases observed in the so 4 2 reduction zone in pore fluids affected by dissolution of evaporites the br cl is often a strong indicator of the degree of evaporation of seawater demonstrated from results obtained in the mediterranean sea dissolution of halites on the other hand leads to br cl much lower than those of sea water in hydrothermal sediments there is no doubt that i and br contents of the fluids are influenced by hydrothermal alteration of the sediments and their organic c but signals are not clear the present study provides an overview of previous dsdp and odp studies of halide distributions in sedimentary pore waters in addition to other contributions on halide distributions in sedimentary pore waters in this symposium volume

timing of post depositional events in the burano formation of the secchia valley upper triassic northern apennines clues from gypsum anhydrite transitions and carbonate metasomatism the burano evaporite formation from the secchia river valley is an up to 2200 m thick sequence composed of meter to decameter scale interbeds of gypsum anhydrite and dolostones with minor halite the deposit has been affected by a complex array of post depositional modifications thermal events and large scale evaporite dissolution preventing a satisfactory reconstruction of the environment of deposition the modifications are intense because these rocks were the main decollement horizon during the formation of the northern apennines chain the carbonate rocks are massive and or laminated dolomitic mudstone wackestone oolitic packstones and oolitic peloidal bioclastic grainstones which commonly appear as mega boudins within a sulfate groundmass the dolostones to 3 7 to 3 0 pdb have been affected by mg metasomatic replacement by magnesite to 2 6 to 1 4 pdb induced by hydrothermal circulation total homogenization temperatures of fluid inclusions in hydrothermal magnesite range from 275 to 310 c the anhydrite rocks are characterized by flow structures such as centimeter scale pseudo lamination composed of aligned prismatic crystals with transposed isoclinal folds outlined by dolostones fragments homogenization temperatures of fluid inclusions in authigenic quartz incorporated into sulfate rocks range from 260 to 305 c emilia and from 230 to 315 c tuscany the gypsum rocks are composed of xenotopic irregular cloudy crystals and more rarely by centimeter scale idiotopic crystals showing the same structures as the anhydrite rocks the origin of the gypsum rocks is due to late alteration of anhydrite by migration of sharp hydration fronts the hydration is a two step process and is revealed by the presence in the gypsum rocks of corroded anhydrite micro relics and authigenic quartz crystals which include anhydrite the role of the burano evaporites during the apennines tectogenesis can be depicted as follows a prevalent deposition of gypsum in the upper triassic b gypsum dehydration at burial conditions to form anhydrite cretaceous c syn tectonic flow of anhydrite rocks brecciation of dolostones syn tectonic growth stage of quartz euhedra at deep burial conditions possibly related to the development of the oligocene miocene greenschist facies apuane metamorphic complex d hydrothermal deposition of sparry magnesite and partial mg metasomatic replacement of dolostones by magnesite e sub surface dissolution of halite to form thick matrix supported residual caprock like anhydrite mega breccias f complete gypsification of anhydrite at sub surface conditions and g evaporite dissolution at surface exposure producing dolostone breccias with partial calcitization and removal of most clasts calcare cavernoso

salt formation associated with sub surface boiling and supercritical water abstract laboratory experiments have demonstrated that supercritical water has extremely low solubility for normal sea salts this fact opens up the possibility for the precipitation of salt from seawater that circulates in faults and fractures close to a heat source in tectonically active basins typically extensional pre rifts and rift settings seawater attains supercritical conditions at depths exceeding 2800 m corresponding to a pressure of 300 bars and temperatures above 405 c salts may also precipitate by the boiling of seawater in sub surface or submarine settings this is demonstrated by a simple laboratory experiment the theoretical basis for the precipitation of salts from seawater attaining supercritical condition has been examined by molecular modelling these processes of salt precipitation constitute a new approach to the geological understanding of salt deposits and two regions are selected to examine whether salt may have deposited under such hydrothermal conditions today the atlantis ii deep in the red sea marine setting and lake asale dallol ethiopia continental setting

a low angle normal fault in the umbria region central italy a mechanical model for the related microseismicity abstract in the northern apennines the upper crust is thinned by a set of east dipping low angle normal faults lanfs the easternmost and more recent of these lanfs is the altotiberina fault atf located in northern umbria the geometry of the atf has been reconstructed matching surface geology with seismic reflection profiles and borehole data the fault whose average dip is 20 borders the upper pliocene quaternary tiber basin and has a displacement of about 8 km the deeper portion of the atf is located below the axial zone of the northern apennines where the strongest instrumental and historical seismicity is recorded the microseismicity of the region m 1 to evaluate the boundary conditions for the brittle activity of the atf the fault can be reactivated for low values of differential stress 1 3 t 10 mpa and tensile fluid overpressure p f 3 e g v 0 93 in the peculiar situation of the northern apennines the deep emissions of large amounts of co 2 documented in the area can be entrapped in their ascent by structural seals e g atf favouring localised fluid overpressures the impossibility of sustaining p f 3 for wide fault portions counteracted by hydraulic fracturing increased permeability under low effective stress and load weakening behaviour for normal faulting would prevent the nucleation of moderate ruptures along the fault the short lived attainment of p f 3 along small fault portions can account for the microseismic activity located along the atf which occurs on rupture surfaces in the range of 10 1 10 3 km 2

upper crustal structure beneath the columbia river basalt group washington gravity interpretation controlled by borehole and seismic studies a three dimensional gravity model based on deep borehole stratigraphy densities from borehole gravimetry and crustal structure from deep seismic and electrical surveys puts limits on sub basalt crustal structure in the northwest quadrant of the columbia plateau washington the gravity model indicates that the miocene columbia river basalt group crbg overlies a broad basin filled with sedimentary rocks that reach thicknesses in excess of 5 km thickest sub basalt sedimentary rocks are beneath the late cenozoic yakima basin analysis of residual gravity shows that the eocene chiwaukum graben does not continue beneath the crbg and that sub basalt sedimentary rocks are not thrust into the cores of the basalt anticlines in the yakima fold belt a gravity high that trends north south in the center of the crbg is probably caused by a broad basement ridge marked by thinner sedimentary rocks beneath the columbia river basalts the western edge of the north south basement high is traced at the surface by the hog ranch naneum ridge a major crustal feature the olympic wallowa lineament is expressed in the gravity field the lineament crosses the north south basement high but does not offset it suggesting that any strike slip motion on the lineament preceded development of the north south basement high an alternative interpretation of the north south gravity high based on a previous seismic study relates it to a high density structure in the crystalline basement perhaps associated with a failed continental rift

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

seismological geological and geophysical constraints for the gualdo tadino fault umbria marche apennines central italy abstract the april 3 1998 mw 5 1 gualdo tadino earthquake central italy was the last significant event in the 6 month long umbria marche seismic crisis this event and its aftershocks occurred in an area where active faulting produces no striking geological and geomorphological effects in this study we investigated the ruptured fault using detailed seismological data and a re processed and re interpreted seismic reflection profile aftershock location and focal mechanisms were used to constrain the geometry and kinematics of the ruptured fault and a comparison was made with the subsurface image provided by the seismic profile we found that the 1998 gualdo tadino earthquake occurred on a wsw dipping normal fault with a length of about 8 km and a relatively gentle dip 30 40 confined between 3 5 and 7 km in depth kinematics of the mainshock and aftershocks revealed a ne trending extension in agreement with the regional stress field active in the northern apennines belt the mw 5 1 earthquake originated above the top of the basement and ruptured within the sedimentary cover which consists of an evaporites carbonates multilayer we hypothesised that the active fault does not reach the surface blind normal fault

tectonic evolution of the eastern margin of the thaumasia plateau mars as inferred from detailed structural mapping and analysis 1 the eastern margin of the thaumasia plateau emtp is characterized by a diversity of tectonic features which recorded its complex and still controversial tectonic history a detailed structural survey and analyses have been carried out in order to assess the kinematics and relative age of the main deformational events combining results from statistics of lineament orientations and density of fault length for each geologic unit and taking into account crosscutting relationships among tectonic structures three main deformational events have been recognized the early stage of the tectonic evolution of emtp is recorded by noachian units at the southern edge of melas dorsa and is represented by n s oriented grabens sutured by early hesperian formations starting from late noachian the extensional stress field became ne sw oriented and resulted in the formation of nw se striking sets of grabens at the boundary between noachian and hesperian the most important change in tectonic regime occurred the hesperian tectonics are characterized by an e w shortening possibly related to an eastward motion of the thaumasia plateau this tectonic phase likely produced a n s oriented wrinkle ridges as well as regional folds and thrust faults e w oriented preexisting tectonic lineaments could have been reactivated forming regional transfer zones in this scenario coprates rise melas dorsa and thaumasia ridge could be interpreted as mountain belts resulting from buckling and thrust faulting of the eastern and southern margins of the thaumasia plateau the proto valles marineris could have experienced a left lateral component of displacement and played a role of a transfer shear zone

geochemical evidence of water source characterization and hydrodynamic responses in a karst aquifer summary the lez karst spring the main perennial outlet of the lez karst system in southern france plays an important role in supplying drinking water to the montpellier metropolitan region in order to investigate the origin of groundwater its circulation patterns and to understand the connectivity and compartmentalization of a karst system a multi tracer approach was used to describe the hydrogeology of the lez karst system groundwater samples were collected from lez karst during a range of hydrologic conditions between march 2006 and august 2009 and analyzed for major and trace elements total organic carbon fecal and total coliform during the first recharge event of autumn highly mineralized water was observed at lez spring during the studied years multiple parameters of water during this rise were monitored with a fine time step in 2008 discriminate factorial analyses revealed the existence of different water types discharging at lez spring during high stage periods highly mineralized water initially discharges from the spring followed by rapid infiltration water this behavior suggests that hydrodynamics affect groundwater circulation by soliciting different endmembers these characteristics were observed on a larger scale when monitoring three intermittent springs connected to lez spring a detailed analysis using bivariate diagrams of major trace elements and elemental ratios provided insight into different water origins associated lithologies and mineral solution reactions related to hydrodynamic responses from the five identified water types the two more contrasting ones are emphasized the first one corresponds to the most geochemically evolved waters issued from deep layers where evaporite chemical fingerprinting has been identified they are characterized by high mineralization and high concentrations in cl na mg li b and br elements and high sr ca mg ca and cl br ratios the second water type corresponds to the most diluted low mineralized waters with high concentrations of no 3 bacteria total organic carbon toc and represents the flux of rapid infiltration waters this endmember underlines the vulnerability of the system to surface infiltration and anthropogenic contamination through the infiltration of water via sinkholes and well developed fracture networks

geochemistry of regional aquifer systems hosted by carbonate evaporite formations in umbria and southern tuscany central italy abstract in central italy mesozoic carbonates represent the principal reservoir of freshwater of the region the hydrogeological setting is linked to the geological evolution of the apennine chain and is generally characterised by a lower aquifer and one or more shallower aquifers separated by thin aquicludes in these systems groundwater composition is the result of a complex array of regional and local geochemical processes the main geochemical processes are the dissolution of calcite the influx of deeply derived co2 related to a regional process of mantle degassing dedolomitization and mixing with deep saline fluids the occurrence of saline fluids characterised by a na cl hco3 composition is related to the presence of a deep regional aquifer at the base of mesozoic carbonates the extremely high pco2 values computed for the saline waters suggest that the deep aquifer is also a structural trap for the mantle derived co2 during its ascent towards the surface in central italy geological and geophysical data highlight the presence of two different crustal sectors the eastern sector where the geometry of the apennine thrust belt is still preserved and the western sector where the compressive structures are dislocated by important extensional deformations in the western sector the normal faults disrupting the compressive structures allow the mixing of the deep na cl hco3 fluids with the shallow groundwater causing a salinity increase and the natural deterioration of groundwater quality

modelling groundwater processes in a carbonate catchment a case study from the madonie area northern sicily abstract this study reports on the results of a hydrogeochemical survey carried out in the madonie area a carbonate massif located in palermo province northern sicily the large dataset 226 collected sites is used to highlight the processes controlling the distribution of dissolved chemicals in groundwaters and more importantly to develop a general model based on reaction path modelling and using the eq3 6 code of rock water reactions in a carbonate environment the investigated groundwater samples have conductivity between 31 7 and 8220 s cm their total dissolved solids tds content is higher near the coast area where the seawater contribution becomes important calcium and hco 3 excess concentrations in groundwaters with respect to the meteoric water seawater mixing line suggest that water rock interactions in carbonate aquifers play a major role on water chemistry using the dataset reaction path modelling is used to simulate the evolution of groundwaters upon interaction with carbonate rocks model simulations are performed in time mode taking into account the mineralogical composition of madonie carbonate rocks and the different dissolution rates of each dissolving mineral the model results of reaction path calculations are in fair agreement with analytical data for natural waters demonstrating the likelihood of model assumptions and supporting further the relevance of carbonate dissolution in determining the chemistry of fluids in the investigated area the developed model is useful for low temperature weathering of carbonate mineral in general and is thus likely to apply in a variety of geological contexts

morphology evolution and tectonics of valles marineris wallslopes mars abstract hillslopes up to 11 km in height can be found along the walls of the valles marineris troughs the widest and deepest troughs are grabens in which tectonics probably exerted the primary control on the wall morphology geographical variations in the wall morphology and profiles show that they result from complex persistent tectonic influences and that significant changes in erosional processes occurred during this evolution from late hesperian to late amazonian preliminary calculations suggest that about 85 95 of the fault controlled wall relief probably formed in an ancient stage prior to this transitional period a study of the volatile content of the wall rocks based upon the morphology and distribution of impact craters on the surrounding plateaus shows that extreme erosional widening of the central valles marineris troughs occurred during the ancient stage of high ground ice content during the subsequent recent stage of tectonic and morphological evolution the wall materials were partly desiccated

hydrogeochemical and isotopic constraints on the origins of dryland salinity murray basin victoria australia abstract combined hydrogeological and hydrogeochemical data allow flow systems and the origins of solutes in the honeysuckle creek area of the southeastern murray basin which is an area affected by dryland salinity to be constrained recharge occurs both on the uplands that are composed of fractured violet town volcanic rocks and the riverine plain that comprises sediments of the shepparton and coonambidgal formations groundwater from the violet town volcanics has low salinity 20 mmol l groundwater has intermediate cl br ratios 600 1000 which indicate that the high salinities do not simply result from halite dissolution rather mixing of groundwater homogenises cl br ratios and evaporation as a consequence of a shallow water table is the dominant process that increases salinity oxygen and h isotopes also indicate that mixing and evaporation have occurred these results indicate that land use over the whole region not just the uplands needs to be considered in any salinity management plans additionally future development of salinity is controlled by depth to the water table on the plains and the efficiency of recharge rather than by salt stores halite or brines in the unsaturated zone

geochemistry and origin of formation brines from the paris basin france 2 saline solutions associated with oil fields abstract oil fields from the paris basin are located in three geological levels dogger middle jurassic rhaetian and keuper upper triassic the origin of water and dissolved salts in saline solutions associated with oil is investigated using the hypothesis that cl and br are conservative in solution in a diagram of cl br ratios vs cl the points of the dogger and the keuper aquifers lie in the zone of primary brines whereas those of the rhaetian are located in the zone of secondary brines the na cl ratio is very high in all of the saline solutions suggesting either a relatively poorly evolved brine at the beginning of halite deposition or some halite dissolution all of the saline solutions especially those from the dogger aquifer are clearly diluted dilution by meteoric waters would not alter the cl br ratio high concentrations of lithium rubidium and boron are attributed to the presence of an extremely evolved brine of marine origin in mixtures of secondary brines formed by dissolution of halite and small amounts of sylvite and ca sulphate mass balance calculations of the excess of cl with respect to na k allows the fraction x of water derived from the primary brine to be calculated assumptions are that all na and k is derived from the secondary brine and that the cl content of the primary brine is constrained by bischofite saturation at 11 000 mmol kg 1 the typical proportion of water from the primary brine waters is 0 7 in the dogger formation and 2 4 in the keuper values of the concentration factor cf expressed as the ratio of the molal concentration of a conservative ion in the evolved brine to its concentration in seawater have been calculated for lithium solutions from the dogger and keuper aquifers have cfli values of 1 8 103 and of 7 7 103 respectively in the rhaetian aquifer the linear relationship between heavy isotope contents of the brine 2h and 18o and the cl content indicates a mixture of two water sources the first one is meteoric water as defined by the intersection of the formation water line with the global meteoric water line 2 h 65 18 o 9 3 the other end member is enriched in heavy isotopes and in cl and is attributed to seawater that has dissolved evaporites mainly halite however the presence of small amounts of an extremely evolved brine is required to account for the bromide lithium rubidium and boron contents of the formation brine from the rhaetian aquifer as this contribution is very limited in amount it cannot affect the heavy isotope content of the formation water mass balance equations are solved for ternary mixtures of meteoric water seawater and brine the same constraints as above no na and k supplied by the primary brine and clbrine 11 000 mmol kg 1 are applied it is also assumed that the seawater component has the same ionic contents as modern seawater and that the salt content of the meteoric component is negligible the fraction of primary brines is x 1 4 according to the cl balance this estimate agrees with that obtained from the lithium balance assuming that the primary brine component was the same as that of the keuper formation water mass balance calculations also indicate that the so42 content of the rhaetian formation water is exclusively due to the secondary brine component in the three saline solutions the very high ca2 contents and high ca 2 mg 2 ratios may be attributed to reaction of the very evolved brine free of so2 4 with gypsum or anhydrite the result is an exchange of mg2 for ca2 which causes a release of ca2 to the solution and a precipitation of secondary mg sulphate this process can also account for the high strontium contents of the analysed samples values of the ratio 87 sr 86 sr are very high in the keuper formation water due to close contact of the solutions with the granitic basement or with granite derived detrital deposits values in the rhaetian and dogger aquifers equal those of upper triassic marine deposits the stable isotope 34s and 18o content of the dissolved aqueous so2 4 indicates a triassic origin for the bulk of sulphate involved in the evolution of formation waters from the rhaetian and from the dogger all geochemical indicators thus show a vertical migration of triassic brines however aqueous so2 4 from the keuper has a permian isotopic signature suggesting a reworking in solution of salts from this period

the crustal structure of the northern apennines central italy an insight by the crop03 seismic line in this paper the crop03 deep seismic reflection profile in the northern apennines is described and re considered in light of new geophysical data and interpretations made available in the last five years particularly from heat flow measurements aeromagnetics tomography active stress determination and passive seismology the crustal structure of the northern apennines is shown to be composed of two distinct domains to the west is the tyrrhenian domain and to the east is the adriatic domain these domains have distinctive geological and geophysical characteristics that exhibit distinct reflectivity patterns at all crustal levels in the tyrrhenian domain the upper oligocene lower miocene compressive structures are no longer recognizable because they are dissected by subsequent extensional tectonic features the seismic profile highlights the strong asymmetry of extensional deformation and the upper crust is affected by a set of six major east dipping low angle normal faults in the adriatic domain compressive tectonics have acted since the middle miocene and the pattern of shallow contractional structures is well preserved the geological interpretation of the seismic data supports a thick skinned style of deformation where the basement is involved in the major thrust sheets the good quality of seismic data also allows for determining the total shortening produced by the contractional structures in the central part of the profile at the border between the tyrrhenian and adriatic domains seismic data shows the presence of an intermediate sector the sector consists of a highly reflective window where the refraction data indicate a local doubling of the crust for about 30 km a scenario is presented that attempts to describe the geodynamics that drove the tectonic evolution of the northern apennines since the upper oligocene

detecting induced correlations in hydrochemistry abstract plots containing common variables are prone to induced correlations these plots are commonly used in hydrochemistry and other branches of geochemistry with no discussion of the potential influence of the common variables on the observed trends some examples from the literature include 1 comparison of a sum to a component of the sum 2 comparison of a ratio to its own numerator or denominator 3 comparison of two ratios with the same numerator or denominator these types of common variable plots may increase or decrease the correlation that exists between two independent variables this paper presents a randomisation method for distinguishing between the real and induced relationships that can occur in plots of type 1 2 or 3 above thereby enabling a distinction between hydrochemical processes and induced correlation s if the slope and correlation coefficient of the actual data are similar to the randomised data the relationship cannot be attributed to a hydrochemical process alone if the slope and correlation coefficient are different it is likely that the data trend is the result of a real process but we recommend this be confirmed using additional evidence such as relationships between other element ion concentrations or independent isotopic evidence common variable plots are useful tools for identifying and describing hydrochemical processes but the data trends need to be tested to ensure that correlations are a result of real processes rather than an artefact caused by a common variable

valles marineris landslides evidence for a strength limit to martian relief abstract unresolved controversies in martian geology surround the role of active tectonics and a wetter climate early in mars history and particularly the history and amount of liquid water at or near the surface among the various lines of evidence brought into such debates are the massive landslides along the walls of valles marineris which generally have been interpreted as resulting from marsquakes and therefore necessitating active tectonics under either wet or dry conditions we analyze valles marineris landslides using digital elevation data from the mars orbiter laser altimeter mola and find that a relief limit consistent with the intact strength of evaporites or other weak sedimentary rock defines an upper bound to the length and relief of unfailed slopes as would material with the strength properties of basalt lithology subjected to ground accelerations of about 0 2 g in contrast to prior interpretations of valles marineris landslides we propose an alternative complementary hypothesis that does not require significant pore water pressures or ground acceleration based on the close correspondence between back calculated material strength properties and values consistent with portions of the chasm walls at least locally being composed of relatively weak materials such as potentially frozen evaporites and or mixtures of ash fall or flow deposits ice hydrated salts and lava flows

dedolomitization as an analogue process for assessing the long term behaviour of a co2 deep geological storage the alicun de las torres thermal system betic cordillera spain abstract carbon dioxide deep geological storage especially in deep saline aquifers is one of the preferred technological options to mitigate the effects of greenhouse gases emissions thus in the last decade studies characterising the behaviour of potential co 2 deep geological storage sites along with thorough safety assessments have been considered essential in order to minimise the risks associated with these sites the study of natural analogues represents the best source of reliable information about the expected hydrogeochemical processes involved in the co 2 storage in such deep saline aquifers in this work a comprehensive study of the hydrogeochemical features and processes taking place at the natural analogue of the alicun de las torres thermal system betic cordillera has been conducted thus the main water co 2 rock interaction processes occurring at the thermal system have been identified quantified and modelled and a principle conclusion is that the hydrogeochemical evolution of the thermal system is controlled by a global dedolomitization process triggered by gypsum dissolution this geochemical process generates a different geochemical environment to that which would result from the exclusive dissolution of carbonates from the deep aquifer which is generally considered as the direct result of co 2 injection in a deep carbonate aquifer therefore discounting of the dedolomitization process in any co 2 deep geological storage may lead to erroneous conclusions this process will also influence the porosity evolution of the co 2 storage formation which is a very relevant parameter when evaluating a reservoir for co 2 storage the geothermometric calculation performed in this work leads to estimate that the thermal water reservoir is located between 650 and 800 m depth which is very close to the minimum required to inject co 2 in a deep geological storage it is clear that the proper characterisation of the features and hydrogeochemical processes taking place at a natural system analogous to a man made deep geological storage will provide useful conceptual semi quantitative and even quantitative information about the processes and consequences that may occur at the artificial storage system

geochemical modeling of the madison aquifer in parts of montana wyoming and south dakota stable isotope data for dissolved carbonate sulfate and sulfide are combined with water compo sition data to construct geochemical reaction models along eight flow paths in the madison aquifer in parts of wyoming montana and south dakota the sulfur isotope data are treated as an isotope dilution problem whereas the carbon isotope data are treated as rayleigh distillations all reaction models reproduce the observed chemical and carbon and sulfur isotopic composition of the final waters and are partially validated by predicting the observed carbon and sulfur isotopic compositions of dolomite and anhydrite from the madison limestone the geochemical reaction models indicate that the dominant groundwater reaction in the madison aquifer is dedolomitization calcite precipita tion and dolomite dissolution driven by anhydrite dissolution sulfate reduction ca mg2 ina cation exchange and halite dissolution are locally important particularly in central montana the groundwater system is treated as closed to c02 gas from external sources such as the soil zone or cross formational leakage but open to c02 from oxidation of organic matter coupled with sulfate reduction and other redox processes occurring within the aquifer the computed mineral mass transfers and modeled sulfur isotopic composition of madison anhydrites are mapped throughout the study area carbon 14 groundwater ages adjusted for the modeled carbon mass transfer range from modem to about 23 000 years b p and indicate flow velocities of 7 7 ftlyr 2 1 26 5 rnlyr most horizontal hydraulic conductivities calculated from darcy s law using the average 14 c flow velocities are within a factor of 5 of those based on digital simulation the calculated mineral mass transfer and adjusted 14 c groundwater ages permit determination of apparent rates of reaction in the aquifer the apparent rate of organic matter oxidation is typically 0 12 jlidol uyr sulfate and to a lesser extent ferric iron are the predominant electron acceptors the kinetic biochemical fractionation of 34 s between sulfate and hydrogen sulfide is approximately 44 o at 25 c with a temperature variation of

theoretical geothermometers andpco2 indicators for aqueous solutions coming from hydrothermal systems of medium low temperature hosted in carbonate evaporite rocks application to the thermal springs of the etruscan swell italy in order to derivet pco2 geoindicators suitable for thermal waters coming from the hydrothermal systems of medium low temperature which are hosted in carbonate evaporite rocks the theoretical concentration of ca mg hco3 so4 f and their complexes in aqueous solutions in equilibrium with a mineral assemblage made up of calcite dolomite anhydrite and fluorite has been calculated at temperatures between 0 and 150 c atpco2 in the 0 1 100 bar interval and for total molality of mobile species na and ci ranging between 0 0001 and 0 3 the results of such calculations indicated that 1 the ca mg s04 and f contents and thes04 f 2 andcamg ratios are potential geothermometers 2 the hc03 2so4 ratio is a pco indicator 3 thehc03f ratio and the hc03 content arc indicators of bothpco2 andt a first geothermometric and geobarometric evaluation of the thermal springs of the etruscan swell generally shows equilibrium temperatures in the interval 50 100 c and pco from about 1 bar to bars these estimations are consistent with the general knowledge of the hydrothermal systems of medium low temperature present in the region

geothermal structure of the tyrrhenian sea over 200 heat flow measurements have been carried out in the tyrrhenian sea mostly since 1977 as part of the heat flow map for italy and surrounding seas italian program as well as part of the french italian tyrrhenia program all data have been corrected for the influence of the plio quaternary sedimentation measured heat flow values were evaluated according to the sedimentary environment following criteria outlined by sclater et al 1980 in this way areas affected mainly by shallow thermal effects in the zones with maximum density of data have been displayed filtering out these shallow contributions the major regional geothermal trends were obtained the tyrrhenian basin can be divided in two distinct regions with different geothermal characteristics the northern part of the basin appears to be connected with the continental structures involved in the interaction between the corsica and tuscan margins the maximum heat flow area located offshore civitavecchia is related to the tensile structures of the tuscan geothermal province the most important thermal features of the central and southern part are located along the central belt trending nw se the lowest heat flow values are located in the peri tyrrhenian areas and are related to the continental margins of the basin while the maxima are connected with the stretched and thinned area localized in the bathyal plain taking into account the heat flow data as well as other geological and geophysical information an evolutionary model for the tyrrhenian sea is presented suggesting a generalized stretching of an initially continental crust accompanied by intensive rifting phases which may have favoured the onset of oceanic type crust

salt tectonics driven by sediment progradation part ii radial spreading of sedimentary lobes prograding above salt experimental models indicate that sedimentary lobes deposited above mobile evaporites deform gravitationally by spreading outward radially radial spreading forms both concentric and radial families of thin skinned grabens that are then pierced diapirically by salt ridges the overburden blocks located between the ridges become subsiding depocenters later continued spreading after depletion of the salt layer forces salt ridges and diapirs to fall forming rapidly subsiding bathymetric lows that channel or trap younger sediments spreading causes large horizontal overburden movements whose distribution and orientation change when the locus of regional deposition shifts

a conceptual model for groundwater circulation using isotopes and geochemical tracers coupled with hydrodynamics a case study of the lez karst system france abstract geochemical and isotopic tracers 18o 2h 87sr 86sr and 13ctdic were used to constrain origins and chemical evolution of groundwater in a mediterranean karst system the lez spring is the main perennial outlet of this karst system and supplies the metropolitan area of montpellier southern france with drinking water groundwater samples were collected at the lez spring and surrounding springs and wells under different hydrodynamic conditions during two hydrological years from june 2008 until may 2010 the results show that multiple hydrological compartments interact through an important network of fractures and faults they notably reveal connections between the main jurassic limestone aquifer and the overlying cretaceous valanginian compartment and between the surface and deep levels of the karst system isotopic tracers provided information about atmospheric recharge origins lithological signatures and chemical evolution of waters long residence time groundwaters issued from deep layers have a triassic hydrochemical fingerprinting being enriched in 13ctdic and characterized by high concentrations in cl as well as high sr ca mg ca and 87sr 86sr ratios evidences suggest that these waters mix with waters from the lower layers of the main jurassic aquifer constitute an intermediate storage compartment prone to rise through piston flow mechanism a two end member hydrograph separation based on ec tds was used to determine the proportion of the deep compartment s contribution to the lez spring outflow on average over the study period the main aquifer compartment and the deep aquifer compartment are estimated to contribute 92 6 and 7 4 of groundwater flow at the lez spring respectively

modeling of grabens extending above evaporites in canyonlands national park utah abstract grabens in canyonlands national park utah began extending above a layer of evaporites when the colorado river cut through the overburden two dimensional finite element models simulate the effects of geometry and rock properties on graben configuration and spacing only those models having a progressively increasing slope or no slope mimicked the natural upslope graben propagation typical rock properties produced the most realistic fault patterns an initial friction angle of 31 a cohesion of 1 mpa and strain weakening comprising cohesion loss and decrease of friction angle to 26 a tensile stress limit narrowed the grabens and reproduced the vertical upper portion of the natural faults the viscous salt resisted overburden spreading and controlled its rate modeled grabens spread at typical rates of 1 2 mm a 1 for a salt viscosity of 1 10 18 pa s and the entire system strained at rates from 6 0 10 14 s 1 to 0 5 10 14 s 1 the faults bounding a graben formed nearly simultaneously at the top surface and propagated downward salt rose beneath the grabens as reactive diapirs overburden adjacent to the canyon flexed as salt was expelled and formed an arching horst and graben a corresponding horst has been found in the field the model results scale to larger dimensions except for the steep upper part of the faults reduced dimensions create vertical or no faults

some results of heterogeneous data inversions for oceanic tides many different instruments directly or indirectly observe the oceanic tidal movements among them we consider here the coastal tide gauge and deep sea pressure recorder which provide at least the principal spectral constituents of the tidal height the gravimeter which indirectly observes the oceanic tides through the gravitational effect generated by the deformation of the solid earth under the ocean tidal mass load and the satellite altimeter which samples the tides in the time domain and over the nearly whole ocean our present paper deals with an empirical method for the recovery of the oceanic tides by inversion of heterogeneous data sets the aim is to take advantage of the different kinds of information coming from the measurement instruments in order to complete more accurate empirical solutions first tide gauge and gravity loading data are separately and jointly inverted to provide global charts of the major semidiurnal m2 wave the results prove that the tide gauge data have a major contribution in the tidal mapping but also suggest that the gravity loading data distort the information this is certainly due to unmodelled geophysical phenomena and instrumental errors second tide gauge and satellite altimeter data are considered in a separate and a joint inversion computation to provide tidal estimations along a predefined geographical line in the north atlantic the results are accurate enough to make provision for the boundary conditions of an hydrodynamical tidal model as an intrinsic advantage of the inversion method a posteriori standard deviations and error covariances for all the solutions displayed are provided and analyzed

hydrogeochemistry of groundwaters from carbonate formations with basal gypsiferous layers an example from the mt catria mt nerone ridge northern appennines italy abstract the mt catria mt nerone mesozoic calcareous ridge contains a defined almost isolated hydrogeological system this system is composed of three main superimposed aquifers separated by marly and marly clayey aquicludes which developed in the calcareous and marly calcareous formations of the umbria marche series the lower water circulation occurs in the massiccio formation where ca mg hco 3 waters mix with underlying gypsum saturated waters due to the presence of triassic evaporites giving rise to ca mg hco 3 so 4 up to ca mg so 4 water types the mixing ratio between the two end members or the degree of gypsum dissolution depends on the depth of water circulation and depth of the top of the triassic evaporites recharge areas for these water types are located at the highest elevations on the ridge while discharge areas occur at springs along the slopes of the main reliefs as well as in two deeply eroded valleys waters recharged in the mt nerone area north western side of the ridge appear to be affected by gypsum and dolomite dissolution caused by a direct interaction at depth with the triassic evaporites followed by calcite precipitation in a closed p co 2 system dedolomitization conversely waters recharged in the mt catria area south eastern side of the ridge seem to be affected by gypsum dissolution and calcite precipitation in an open p co 2 system which produces fracture sealing of the upper parts 120 m of the massiccio formation and a confinement of the deep waters the consequent pressurization causes additional gypsum dissolution without calcite precipitation in a closed p co 2 system previous hypotheses of hydraulic continuity of the basal aquifer throughout the calcareous ridge are reconsidered here and a new interpretation based on hydrochemical data is provided

debris flow origin for the simud tiu deposit on mars a late hesperian smooth plains deposit on mars interpreted as a debris flow extends more than 2000 km from hydraotes chaos through simud and tiu valles and into chryse planitia the simud tiu deposit widens out to 1000 km and embays streamlined landforms and knobs made up of sedimentary and perhaps volcanic deposits that were carved by earlier channeling activity morphologic features of the simud tiu deposit observed in viking and pathfinder images are generally consistent with a debris flow origin but some of the deposit s salient features are not readily explained by catastrophic flooding or ice flow internal depressions appear to be bounded by linear scarps along flow margins where differential shearing may have occurred and in areas where flow spreading may have produced zones of extensional breakup and thinning within the flow possible flow lobes within the deposit may have formed by successive flow surges within the flow unit the pathfinder landing site is on the simud tiu deposit and the observations there are consistent with debris flow the low longitudinal ridges at the site may have formed by clast interactions as the flow ground to a halt imbricated planar rocks on the ridges such as in the rock garden also may have been emplaced by debris or ice flow however stream energy calculations at ares vallis and channel geology indicate that flooding probably was incapable of emplacing the meter size boulders observed at the pathfinder site dewatering of pressurized zones in the debris flow or underlying material may be responsible for mud eruptions that formed a couple of patches of low pancakelike shields up to 5 km in diameter and for probable water flows that formed two small rille channels a few kilometers long local irregular grooves may be cracks that resulted from later desiccation and contraction of the flow material the debris flow unit apparently coalesced from outflows of water fluidized debris originating from beneath chaotic and hummocky terrains within and along the margins of simud and tiu valles the deposit is onlapped from the north by another flow deposit originating from acidalia planitia if the simud tiu debris flow had entered a standing body of water a turbidity current may have arisen from the debris flow and then backflowed over the debris flow to account for the acidalia deposit

rate of diffuse carbon dioxide earth degassing estimated from carbon balance of regional aquifers the case of central apennine italy central italy is characterized by an anomalous flux of deeply derived co2 in the western tyrrhenian sector of central italy co2 degassing occurs mainly from focused emissions vents and strong diffuse degassing and thermal springs whereas in the eastern apennine area deep co2 is dissolved in cold groundwaters of regional aquifers hosted by mesozoic carbonate evaporite formations influx of deep co2 into 12 carbonate aquifers 12 500 km2 of the central apennine is computed through a carbon mass balance that couples aquifer geochemistry with isotopic and hydrogeological data mass balance calculations estimate that 6 5 1010 mol yr 1 of inorganic carbon are dissolved in the studied aquifers approximately 23 of this amount derives from biological sources active during the infiltration of the recharge waters 36 comes from carbonate dissolution while 41 is representative of deep carbon sources characterized by a common isotopic signature 13c 3 the calculated deep co2 influx rate ranges from 105 to 107 mol yr 1 km 2 increasing regionally from east to west in the study area

energetics of calcium rich dolomite abstract the enthalpy of formation of sedimentary ca rich dolomite has been determined by oxide melt calorimetry the results show that ca rich dolomite is energetically different from well ordered stoichiometric dolomite the enthalpy of formation from calcite and magnesite becomes strongly more endothermic with increasing excess ca content this supports the idea that the substitution of ca in the mg layer of dolomite is energetically unfavorable ca rich dolomite is unstable relative to well ordered stoichiometric dolomite and calcite the enthalpy behavior for excess ca substitution in dolomite is different from that of mg substitution in calcite the enthalpy change is much larger in magnitude in dolomite and is more strongly dependent on composition differences in cation order as well as the presence of a modulated structure and low symmetry domains in ca rich dolomite cannot be discerned from the enthalpy data the findings confirm that the growth and occurrence of ca rich dolomite in sedimentary environments must be attributed to kinetic factors rather than to equilibrium

cl br ratios and environmental isotopes as indicators of recharge variability and groundwater flow an example from the southeast murray basin australia abstract systematic variations in cl br ratios together with r 36 cl values 14 c activities and 18 o values reflect differences in groundwater recharge and define groundwater flow paths in the riverine province of the southeast murray basin in groundwater from the shallowest shepparton formation homogenisation of cl br and 18 o values and a decline in 14 c activities with depth imply that vertical flow dominates the 14 c activities define variations in pre land clearing recharge in the palaeovalleys of present day rivers deep leads which contain sandier sediments higher recharge 0 5 to 1 4 mm year produced relatively fresh groundwater tds 36 cl values in groundwater from the goulburn subcatchment zones of groundwater with variable cl br ratios in the deeper calivil renmark aquifer also allow the detection of rapid leakage from the surface that has the potential to compromise groundwater resources

saline ground waters and brines in the canadian shield geochemical and isotopic evidence for a residual evaporite brine component abstract saline ca na cl type groundwaters and brines sampled in deep mines over an extensive area of the canadian precambrian shield have elevated br cl ratios which may indicate that the chlorinity of these waters was derived from the infiltration of residual evaporitic brines remnants of the great marine incursions of the paleozoic era boron concentrations in these waters are generally low i e 11 b 10 b ratios of these waters are significantly greater than the average value for continental crustal rocks with the highest values 4 19 approaching that of present day seawater 4 20 moreover the boron isotopic ratios generally trend to higher values with increasing chlorinity which supports the conclusion from the br cl relationship that most of the chloride in shield brines is of marine origin rather than a product of water rock interactions if this is correct crystalline rocks must then be sufficiently permeable on a regional scale to have allowed the brine to infiltrate to depths of several kilometers where it now resides

the evaporation path of seawater and the coprecipitation of br and k with halite brines and salt were sampled at the morton bahamas solar salt production facility on great inagua island in the bahamas the brines were analyzed by ion chromatography to define more precisely than heretofore the evaporation path of seawater to the end of the halite facies at inagua calcium carbonate begins to precipitate at a brine concentration factor of 1 8 times that of seawater gypsum begins to precipitate at a brine concentration of 3 8 times seawater and halite at a concentration factor of 10 6 three of the most concentrated brines from inagua 40 times seawater were evaporated further in the laboratory magnesium sulfate first precipitated at brine concentrations about 70 times those of seawater and potassium bearing phases began to precipitate for these brines at concentrations greater than 90 times those of seawater the distribution of coefficients of br and k between brines and halite were determined by combining analytical data for the inagua brines with measurements of the br and k content of halites from inagua and of halite which had precipitated from inagua brines during storage the observed average value of dbr is 0 032 in good agreement with some of the previous measurements the measured values of dk are highly variable 0 001 to 0 021 dk for halite precipitated early in the halite facies is in the vicinity of 0 015

evaluating the geogenic co2 flux from geothermal areas by analysing quaternary travertine masses new data from western central italy and review of previous co2 flux data abstract quantification of carbon fluxes between solid earth and its atmosphere is necessary to understand the global geological carbon cycle some of the main co2 contributors are metamorphism and magmatic mantle degassing co2 is discharged from active and quiescent volcanoes fault zones geothermal systems and co2 rich groundwater here a new method for the estimation of the geogenic flux of co2 from tectonically active regions based on the volume composition and age of travertine deposits is proposed the method is applied to the travertine deposits of western central italy where travertine deposition is driven by degassing of co2 charged groundwater results show that the study areas are characterized since middle pleistocene by diffuse co2 degassing processes with time averaged co2 fluxes ranging between 1 24 0 12 106 mol y 1 km 2 and 1 38 0 42 106 mol y 1 km 2 these values are of the same order of magnitude of carbon dioxide fluxes measured by different methods in western central italy and are higher than the global baseline co2 flux from high heat flow regions the review of the available 234u 230th and 14c data shows that the co2 degassing processes that affects western central italy nowadays were already active at least 350 ka ago proving that this region is a globally relevant case for the study of earth degassing considering the widespread occurrence of travertine deposits in tectonically active areas worldwide the proposed approach can be used as a reliable tool to estimate the co2 flux in different geodynamic settings within system earth

hydrogeochemical processes in clastic sedimentary rocks south korea a natural analogue study of the role of dedolomitization in geologic carbon storage abstract for long term mineral trapping of sequestered co 2 in deep saline aquifers base cations such as ca 2 and mg 2 are essential as a natural analogue study of geologic carbon storage in deep aquifers hosted in sedimentary formations we examined the hydrochemistry of sulfate rich up to 1140 mg l so 4 2 and moderately high p co 2 10 1 1 to 10 2 4 atm groundwater in a cretaceous non marine sedimentary basin in south korea with the objective to elucidate water rock interactions controlling the concentrations and behavior of base cations principal component analysis of the acquired hydrochemical data indicated that dissolution of carbonates calcite and dolomite and evaporite minerals halite and gypsum controls the chemical composition of groundwater resulting in substantial increases of the concentration s of ca 2 mg 2 na cl so 4 2 and total dissolved solids tds in deep groundwater na versus cl and ca 2 mg 2 versus hco 3 so 4 2 plots provided evidence for dissolution of halite and gypsum progressively increasing 34 s values of dissolved so 4 2 from 15 1 to 19 2 with increasing sulfate concentrations indicated gypsum dissolution ion ion plots esp mg 2 ca 2 ca 2 so 4 2 and mg 2 so 4 2 and saturation indices of calcite dolomite and gypsum suggest that the groundwater chemistry esp the concentrations of ca 2 and mg 2 is controlled by dedolomitization driven by gypsum dissolution groundwater in the study area does not reach complete equilibrium with respect to calcite and dolomite because of gypsum dissolution which controls the mg 2 ca 2 ratios of groundwater continued calcite precipitation triggered by an excess ca supply from gypsum dissolution reduces the concentrations of dissolved inorganic carbon dic in groundwater the increase of 13 c dic values from 11 1 to 6 5 concomitantly with increasing sulfate concentration was explained via geochemical modeling by dedolomitization under the rate constant ratio of about 0 038 between dolomite and calcite the model results agree well with the observed mg 2 ca 2 ratios and further suggest a potential increase of the void volume in the aquifer through dedolomitization by about 0 72 cm 3 l based on this analogue we suggest that dedolomitization in concert with dissolution of gypsum may constitute an important process releasing base cations for mineral trapping of injected co 2 in non marine clastic sedimentary strata containing carbonates and gypsum in south korea and elsewhere

a combined geochemical and isotopic study of the fluids discharged from the montecatini thermal system nw tuscany italy abstract the thermo mineral fluids discharges of montecatini terme northern apennines tuscany italy have been exploited since the roman times and despite the fact that this thermal complex is one of the biggest in europe the most recent geochemical investigations were published almost 40 years ago to fill this gap in this paper a detailed geochemical and isotopic investigation on the main thermal springs and wells from the montecatini thermal system mts is presented the chemical and isotopic features of the montecatini waters suggested that they are mainly controlled by water rock interaction processes between meteoric water permeating at depth from the surrounding reliefs up to 800 m a s l and the triassic evaporites burano formation belonging to the tuscan sedimentary series the local stratigraphic and tectonic framework favors an efficient recharge of the hydrothermal reservoir by the meteoric precipitation from a large catchment area and this aspect plays a fundamental role for the longevity of the montecatini thermal spas notwithstanding the huge amount of thermal water exploited the 3h values indicated that the thermal waters are likely related to a relatively long 50 years fluid circulation pattern approaching the surface thermal and saline waters mix with cold and low tds total dissolved solids waters hosted in short shallow aquifer s whose chemistry is dictated by the interaction of rain waters with silico clastic rocks of low solubility geothermometric estimations in the f so42 hco3 system suggested the occurrence of a main fluid reservoir at t 80 95 c and pco2 0 5 bars such co2 pressure is consistent with values estimated for other thermal springs from central southern tuscany being co2 basically supplied by a deep source nevertheless 13c co2 and 13c tdic values were lower than those expected for a mantle thermometamorphic co2 source this can be explained by i isotopic fractionation occurring during calcite precipitation and or ii mixing with biogenically derived gases occurring at relatively shallow depth

co2 water mineral reactions during co2 leakage geochemical and isotopic monitoring of a co2 injection field test a shallow co2 injection experiment was performed at the co2fieldlab site near svelvik norway in sept 2011 the gas was injected through a 45 inclined well to a target depth of 20 m its aim was to test various geophysical and geochemical monitoring tools for integrated near surface leakage monitoring a total of 1 67 t of co2 was injected over a period of six days groundwater level was at 60 cm depth and a complex salinity stratification with brackish water overlying fresh and saltwater was observed at the beginning of the experiment four water sampling boreholes were located at each corner of a square configuration of 8 m with the nominal injection at the center from baseline conditions to the post co2 injection phase ph temperature and electrical conduc tivity of the groundwater were measured collecting water samples at three different depths 5 10 and 15 m for analyses of major minor and trace elements ca na so4 cl mg al ba mn ni co b li and isotopes 11b 7li 34sso4 18oso4 87sr 86sr 18oh2o 2hh2o significant changes in chemical and isotope signatures of water over the duration of the experiment indicated two processes 1 binary mixing with seawater and rainwa ter as the possible end members due to a near seashore location and 2 co2 water rock interactions enhanced by dissolved co2 causing acid conditions and favoring rock dissolution the relative contribution of those pro cesses was quantified by a mass balance model and equilibrium calculations this comprehensive geochemical and isotope approach allowed discriminating reactive mechanisms from non reactive mixing processes asso ciated with co2 leaks within an aquifer with a strong conductivity stratification and heterogeneous mineralogy and this approach seems promising for investigating co2 leaks at field scale