the origin and growth of a recently active fissure ridge travertine over a seismic fault tivoli italy abstract an enigmatic c 2 km long and 15 m high travertine ridge the colle fiorito ridge occurs in the northwestern sector of the tivoli travertine plateau central italy the main questions addressed in this paper concern the origin and mode of growth of this prominent ridge the presence of active structures beneath the studied ridge is inferred by recent and past earthquakes located at shallow depths immediately beneath colle fiorito to understand the surficial structure of the colle fiorito ridge and the travertine depositional environment we constructed a 10 m resolution dem analyzed recent and past aerial photographs and conducted field surveys and meso to micro scale sedimentological analyses to understand the ridge subsurface structure we studied a set of 32 stratigraphic well logs available from previous works and from the local decorative stone industry and realized a 2d electrical resistivity tomography ert across the ridge results show a gentle antiformal structure affected by subvertical zones of strata discontinuity the colle fiorito structure is interpreted as a previously unknown fissure ridge travertine grown at the edge of the tivoli travertine plateau perhaps when the volumetric deposition rate reached its climax in the plateau for the abundance of fluid discharge and the rise of the water table such a fluid pressure may have activated the faults and fractures beneath colle fiorito thus opening new pathways for the ascension of geothermal fluids toward the surface

comparison of the quaternary travertine sites in the denizli extensional basin based on their depositional and geochemical data abstract in the denizli basin turkey located in the western anatolian extensional province travertine and tufa deposition has been an ongoing process for at least 600 000 years travertine bodies which are 30 to 75 m thick and each covers areas of 1 to 34 km2 are up to 1 km3 in volume today spring waters in this area have temperatures of 19 to 57 c are of the ca mg hco3 so4 type in the pamukkale kelkaya and pinarbasi areas and the ca mg so4 hco3 type at cukurbag thermal waters along the northern margin of the basin are generally hotter than those in the east southeast and south the 18o and d values of the spring waters indicate a meteoric origin the average temperatures of the hydrothermal systems in the denizli basin appear to have decreased from pleistocene to holocene travertine which formed from the hotter water is more widespread than the tufa that formed in the cooler spring waters deposition of the travertine which formed largely on slopes in depressions and along fissure ridges mostly on northern basin margins was controlled by the interplay between various intrinsic and extrinsic parameters the travertines are formed largely of calcite with only minor amounts of aragonite in some of the vertically banded crystalline crust raft and pisoid travertines found in some of the northern sites the aragonitic samples rich in sr are typically found around the spring orifices and along the central axis of the fissure ridges the stable isotope values of the travertine found in the northwest and southeast parts of the basin are different the 13c values of the northern travertine deposits are more positive 3 7 to 11 7 vpbd than those found in the south southeast areas 4 to 5 8 vpdb in contrast the travertine and tufa in the southeastern areas have higher 18o values 15 2 to 7 8 vpdb than those of the northern areas 16 6 to 4 8 vpdb available evidence indicates that spring activity and associated travertine precipitation in the denizli basin were controlled largely by tectonic activity rather than by climatic conditions

radiocarbon dating of residual organic matter in travertine formed along the yumoto fault in oga peninsula northeast japan implications for long term hot spring activity under the influence of earthquakes abstract radiocarbon dating was performed on trace amounts of organic matter included in travertines formed along the yumoto fault in oga peninsula ne japan the reliability of the dating method was confirmed by the consistency of ages obtained with the stratigraphy of the travertine mound and the ratio of carbon stable isotopes the radiocarbon chronology of the travertines shows that 1 the hot springs at oga have been active for approximately 29 000 years with average depositional rates ranging from 0 24 to 1 75 mm yr and 2 the principal hot spring activity has migrated southward with time variations in the accumulation rates and the progressive migration of the main focus of the hot spring activity imply irregular spring behaviour this behaviour has not been influenced by paleoclimate but may have been controlled by the earthquakes that occur frequently in the region around oga peninsula

younger dryas event recorded by the mirabilite deposition in huahai lake hexi corridor nw china abstract deposits from the huahai ancient lake in the hexi corridor were dated using conventional and ams 14c a 2500a carbon storage effect was defined at 9 25 m depth according to the 14c age difference between a plant macrofragment and detrital organic matter from the same layer the chronology of this strata indicated that the mirabilite layer at the depth of 8 05 m 9 15 m had formed during the younger dryas yd event the formation of the mirabilite layer indicated that the mean annual temperature in the hexi corridor dropped by 11 c during the yd event compared with today the lowest cold event occurred early in the yd which is consistent with what has been revealed by other high resolution records such as those of arctic ice cores and stalagmites in mid latitude regions

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

geochemical transect through a travertine mount a detailed record of co 2 enriched fluid leakage from late pleistocene to present day little grand wash fault utah usa abstract active and fossil endogenic travertine mounts scattered along the little grand wash fault are studied as records of quaternary co 2 enriched fluid leakage this study focusses on a particular area where a fossil mount formed in a near surface setting by successive circulation sealing episodes from late pleistocene to mid holocene and where a modern surface travertine is still being formed by a co 2 enriched fluid source the fossil mount is composed of horizontal and vertical veins whereby the vertical veins recorded numerous cycles of circulation sealing dissolution events and were used as conduits for the co 2 enriched fluid circulation from the depth to the surface or along sub horizontal fractures where successive precipitation events are recorded the modern travertine is being built at the surface by successive eruption of crystal geyser an anthropic geyser active since the 1930 s 13 c and 18 o signatures and u th datings ranging from 11 5 ky till present day allows calibrating in detail the co 2 enriched fluid leakage along a single fault segment and in a post glacial context as last glaciations in the study area took place 15 ky ago the dataset shows a high decrease of the oxygen stable isotope values till about 6 ky then the variations reflect a constant range until present day this tends to restrain the period of local increase of the meteoric water input in the aquifer that is sourcing the co 2 enriched water the fossil travertine represents a 7 ky long record of co 2 leakage above a natural reservoir from late pleistocene to mid holocene the flux of co 2 leakage through time and the total escaping volume have been computed and appears to be low in comparison with an anthropogenic leak provoked for instance by a non sealed well

degassing of mantle derived co2 and he from springs in the southern colorado plateau region neotectonic connections and implications for groundwater systems groundwaters of the southern colorado plateau arizona transition zone region are a heterogeneous mixture of chemically diverse waters including meteoric epigenic fluids karst aquifer waters and deeply sourced endogenic fluids we investigate the composition of travertine depositing co 2 rich springs to determine the origin transport and mixing of these various components the san francisco mountain recharge area has little surface flow instead waters discharge through major springs hundreds of kilometers away about 70 9340 l s of the total recharge 13 500 l s discharges 100 km to the north in the incised aquifer system at grand canyon most of this water 85 8070 l s emerges through two travertine depositing karst spring systems blue springs 6230 l s and havasu springs 1840 l s about 30 of recharge 4150 l s flows to the south and discharges along nw striking faults in the arizona transition zone forming the base flow for the verde river geochemical data define regional mixing trends between meteoric recharge and different endogenic end members that range from bicarbonate waters to sulfate waters water quality in the region is dictated by the percentage and character of the endogenic inputs that cause a measurable degradation of groundwater quality for water supply sources for the high co 2 include dissolution of limestone and dolostone c carb and external carbon c external c external is computed as the bicarbonate alkalinity dissolved inorganic carbon dic minus the c carb c external dic c carb c external is deconvolved using carbon isotopes into biogenically derived sedimentary carbon c organic and deep co 2 inputs c endogenic measured 13 c values are 17 to 3 versus pee dee belemnite pdb assuming 13 c carb 2 13 c organic 28 and 13 c endogenic 5 water chemistry mixing models indicate that an average of 42 of the total dic comes from dissolution of carbonate rocks 25 from organic carbon including soil respired co 2 and 33 from deep endogenic sources helium isotope values 3 he 4 he in gases dissolved in spring waters in the southern colorado plateau region range from 0 10 to 1 16 r a relative to air indicating that a significant component of the deeply derived fluid is from the mantle mean of 5 asthenospheric or 10 subcontinental lithospheric mantle source measured co 2 3 he ratios of 2 10 9 to 1 4 10 13 are adjusted by removing the proportion of co 2 from c carb and c organic to give values 10 for all but four samples various mixing models using co 2 3 he suggest that the mantle derived components of the co 2 load are highly variable from spring to spring and may make up an average of 10 of the total co 2 load of the regional springs fluid rock interactions involving endogenic fluids are suggested by 87 sr 86 sr 18 o and other tracers the endogenic co 2 component multiplied by discharge for each spring yields an integrated annual flux of deeply derived co 2 to the groundwater system of 1 4 10 9 mol yr this co 2 emission from the colorado plateau region reflects a complex tectonic evolution involving laramide hydration of the lithosphere above the farallon slab addition of fluids from mid tertiary mantle tectonism during slab removal and ongoing fluid movement induced by neotectonic small scale asthenospheric convection

proterozoic multistage ca 1 1 and 0 8 ga extension recorded in the grand canyon supergroup and establishment of northwest and north trending tectonic grains in the southwestern united states the grand canyon supergroup records at least two distinct periods of intracratonic extension and sedimentation in the late mesoproterozoic and neoproterozoic new 40 ar 39 ar age determinations indicate that the mesoproterozoic unkar group was deposited between ca 1 2 and 1 1 ga basins in which the unkar group was deposited and the related northwest striking faults were created by northeast southwest extension which was contemporaneous with regional northwest southeast grenville contraction new u pb data indicate that the neoproterozoic chuar group was deposited between 800 and 742 ma sedimentary and tectonic studies show that chuar deposition took place during east west extension and resulting normal slip across the butte fault this event is interpreted to be an intracratonic response to the breakup of rodinia and initiation of the cordilleran rift margin laramide monoclines of the grand canyon region have north and northwest trends reactivate faults that originated at the time of unkar and chuar deposition and can be traced for great distances hundreds of kilometers from the grand canyon we use the distribution of monoclines in the southwest to infer the extent of proterozoic extensional fault systems the 1 1 ga northwest trending structures and ca 800 700 ma north trending extensional structures created regional fault networks that were tectonically inverted during formation of the ancestral rocky mountains and laramide contraction and reactivated during tertiary extension

morphotectonics of fissure ridge travertines from geothermal areas of mammoth hot springs wyoming and bridgeport california abstract eleven quaternary fissure ridge travertines from mammoth hot springs wyoming and seventeen ones from bridgeport california were mapped and studied with a morphotectonic approach to understand possible relationships between travertines and active versus passive tectonics results are compared with other known geothermal fissure ridges on the earth the studied fissure ridges are all located in the hangingwall of normal faults but the fissure ridges appear as non dislocated by faults rather by axial fissures both in the two principal study areas and elsewhere azimuthal analyses of faults and fissure ridges show that the distribution of fissure ridge long axis is rather dispersed around the strike of the local normal faults no correlation occurs between the fissure ridge length and the angle between the strike of the normal fault and the strike of fissure ridges the studied fissure ridges are 2 to 360 m long mean length 72 1 m 1 to 15 m wide mean width 6 7 m and 0 5 to 8 m high mean height 3 9 m fissure ridge aspect ratios show a moderate correlation between the length and both the width and the height of fissure ridges whereas the correlation between width and height is less marked the growth in height and width of ridges appears as much more inhibited than in length a model is proposed in which fissure ridge travertines grow with enhanced elongation along one sub horizontal direction which seems moderately controlled by the associated normal fault and the regional extension other factors such as the inherited fracture network and the geothermal and artesian pressure of fluids fluid discharge may be important in the development of the studied fissure ridges results from this study may contribute to the knowledge of factors that control the long term geothermal circulation and also the long term hermetic durability of co 2 subsurface repositories

plateau versus fissure ridge travertines from quaternary geothermal springs of italy and turkey interactions and feedbacks between fluid discharge paleoclimate and tectonics abstract morphologically different deposits of thermal travertines are known worldwide but what factors controlled their morphology volume and growth for tens of thousands of years is only partially understood two main morphotypes of quaternary thermal travertines are reconsidered here to understand the reasons for their differential growth the fissure ridge travertines of denizli basin western turkey and the travertine plateau of tivoli central italy for comparable longevities and average vertical deposition rates the main differences between the studied travertines are as follows 1 volume of the travertine plateau is about one hundred times larger than each fissure ridge 2 despite a larger volume the travertine plateau does not produce relief whereas the fissure ridges produce a characteristic prominent topography 3 the travertine plateau grew primarily through lateral progradation whereas the fissure ridges through vertical aggradation 4 travertine deposition occurred in different environments principally low energy flat or shallow environments at tivoli and high energy inclined environments at denizli 5 the growth of the tivoli plateau occurred in a subsiding basin whereas the fissure ridges were not influenced by significant subsidence 6 c and o isotope signatures from the two studied travertines are different 7 despite similar annual precipitations the present water discharge in the tivoli area is about ten times greater than that of the denizli basin u series ages from the two deposits are correlated with paleoclimate oscillations at regional and global scales geological field evidence together with paleoclimate correlations suggest that in both the study cases the main body of travertine deposits the bedded travertine grew preferentially when the water table was high warm and or humid periods conversely when the water table was depressed cold and or dry periods the tivoli travertine underwent partial erosion and the denizli ridges were cut by axial veins and lateral sill like structures filled by banded sparitic travertine a comparative model is proposed where the main factor driving the difference in the morphostratigraphic architecture of fissure ridges and travertine plateaus is the volume of water discharge a high discharge rate resulted in the precipitation of caco3 far away from the springs hence driving the lateral progradation of the tivoli plateau a reduced discharge rate caused travertine precipitation close to the springs thus causing the vertical aggradation of the denizli fissure ridges paleoclimate oscillations must have controlled the amount of fluid discharge which in turn must have influenced the opening of the feeding fractures by an increased pore pressure

mixed geothermal and shallow meteoric origin of opal and calcite beds in pliocene lower pleistocene axial fluvial strata southern rio grande rift rincon hills new mexico u s a abstract exposed in upper pliocene fluvial strata in the eastern rincon hills and adjacent jornada del muerto basin southern rio grande rift new mexico usa are five laterally continuous beds 0 2 to 1 0 m thick of opal ct which straddle the east rincon hills normal fault four of these opal beds change basinward over 1 km or less to white friable lithofeldspathic sand with opal glaebules and then to microcrystalline calcite the opal and calcite generally replaced fine sand at shallow depths although two beds locally precipitated from standing water 87sr 86sr values 0 71301 to 0 71724 of the opal beds are consistent with precipitation from an advecting high temperature geothermal fluid that flowed through bedrock and or from a high temperature geothermal fluid derived from a deep crustal source carbon and oxygen isotopic values 13cpdb 7 1 to 0 6 18opdb 9 1 to 5 6 of the calcite beds lie between and overlap those of paleozoic carbonate and pliocene paleosol calcite suggesting precipitation from a mixture of a high temperature geothermal fluid that interacted with paleozoic carbonates and shallow meteoric groundwater for which paleosol calcite is a proxy the geothermal fluids are interpreted to have upwelled along the east rincon hills fault flowed laterally at or just below the surface and precipitated opal in response to rapid cooling and evaporation downflow precipitation of opal glaebules occurred as a result of decreasing silica concentrations and perhaps by mixing with shallow meteoric groundwater from which calcite precipitated probably by co2 degassing

desert wetlands in the geologic record abstract desert wetlands support flora and fauna in a variety of hydrologic settings including seeps springs marshes wet meadows ponds and spring pools over time eolian alluvial and fluvial sediments become trapped in these settings by a combination of wet ground conditions and dense plant cover the result is a unique combination of clastic sediments chemical precipitates and organic matter that is preserved in the geologic record as ground water discharge gwd deposits gwd deposits contain information on the timing and magnitude of past changes in water table levels and therefore are a potential source of paleohydrologic and paleoclimatic information in addition they can be important archeological and paleontological archives because desert wetlands provide reliable sources of fresh water and thus act as focal points for human and faunal activities in some of the world s harshest and driest lands here we review some of the physical sedimentological and geochemical characteristics common to gwd deposits and provide a contextual framework that researchers can use to identify and interpret geologic deposits associated with desert wetlands we discuss several lines of evidence used to differentiate gwd deposits from lake deposits they are commonly confused and examine how various types of microbiota and depositional facies aid in reconstructing past environmental and hydrologic conditions we also review how late quaternary gwd deposits are dated as well as methods used to investigate desert wetlands deeper in geologic time we end by evaluating the strengths and limitations of hydrologic and climatic records derived from gwd deposits and suggest several avenues of potential future research to further develop and utilize these unique and complex systems

the fate of mantle derived carbon in a continental sedimentary basin integration of c he relationships and stable isotope signatures abstract the isotopic composition and abundances of the rare gases he ne and ar and active gases co2 ch4 have been determined in a series of commercial gas reservoirs in the pannonian and vienna basins of hungary and austria respectively in these zones of continental extension significant components of mantle derived 4he up to 39 8 and 21ne up to 58 are identified the results of this study indicate a major component of mantle derived carbon in these systems as well ranging in composition from close to 100 co2 to ch4 dominated reservoirs with trace concentrations ppm of co2 these gas reservoirs provide a unique opportunity to examine the relationship of the conservative rare gases to the active gas components and to examine the sources and sinks for mantle and crustal derived carbon phases with the exception of kismarja gas field which shows evidence of addition of 3he depleted crustal co2 all gas fields exhibit a trend whereby the most co2 rich samples approach co 2 3 he mntl values similar to morb 2 109 to 7 109 while co2 depleted samples extend to co 2 3 he mntl values as low as 105 the lack of any correlation of co 2 3 he mntl ratios with r ra values indicates the observed trends are not a function of mixing between crustal and mantle derived endmembers but instead reflect progressive loss of the mantle derived co2 carrier phase during volatile transport and emplacement in the continental crust based on stable isotopic signatures from the kismarja field a crustal co2 endmember with an isotopic composition of 6 8 and a mantle co2 endmember with an isotopic composition no more depleted in 13c than 5 0 can be identified one of the few instances where the isotopic signatures of mantle and crustal derived co2 can be reliably distinguished in a continental setting covariation in 13cco2 and 13cch4 values in the gas fields is used to place constraints on two alternative models whereby the trends in percent co2 and co 2 3 he mntl ratios can be accounted for by 1 loss of the mantle derived co2 carrier phase 2 addition of crustal derived co2 3 addition of crustal derived thermogenic ch4 and potentially 4 conversion of the co2mntl carrier phase to mantle derived ch4 based on an estimated total mantle 4he flux for the pannonian basin of 4 2 108 atoms m 2 s 1 mantle carbon flux estimates for this basin alone range from 3 108 g c yr to 1 109 g c yr which over the lifetime of the basin is only 4 5 orders of magnitude less than flux estimates based on the total area of the spreading ridges clearly the addition of mantle derived carbon to the crust in areas of continental extension is significant and may have been previously underestimated we demonstrate here that integration of 13c data with rare gas isotopic tracers provides an important tool in constraining models of mantle carbon sources and sinks in continental settings

a multidisciplinary approach to understanding carbonate deposition under tectonically controlled hydrothermal circulation a case study from a recent travertine mound in the euganean hydrothermal system northern italy a multidisciplinary study was carried out on an upper pleistocene travertine mound montirone hill abano terme south of padova veneto italy with the aim of developing a comprehensive understanding of the processes interacting in structurally controlled thermal springs and the consequent deposition of thermal limestones the sedimentology geochemistry structural characteristics and hydrogeology of the mound which is associated with the euganean geothermal field and the related complex structural framework of the schio vicenza fault system were investigated a palaeo environmental model of the deposit has been reconstructed clarifying the connection between the travertine deposition and the regional structural setting calcium rich thermal waters rose from spring orifices estimated temperature from 54 c to 61 c based on geochemical calculations and produced a mound made of coalescent shield like bodies the dominant lime mudstone facies resulted from the accumulation of lime mud at the bottom of shallow crater like basins located on top of stacked cones soft sediment deformations affecting the lime mud sediment were most probably produced by the recurrent uprising of gas bubbles the overlying crystalline crusts were deposited on the flanks of the mound by waters overflowing from the vents with laminar flux a deep hydrothermal circuit with a long period of water rock interaction is supported by geochemical analyses furthermore a local extensional regime enhancing the migration of thermal fluids to the surface is inferred based on the results of the structural analysis carried out on the fault fracture mesh that affects the mound these results corroborate the well established relation among travertine deposits hydrothermal systems and fault systems and substantiate the structurally controlled conceptual model of the euganean hydrothermal system suggesting that both the thermal and the fault systems were active at least since 34 ka

origins of elements building travertine and tufa new perspectives provided by isotopic and geochemical tracers fluid rock interaction represents a major process in the formation of calcitic or aragonitic travertine and tufa catt in most cases catt is associated to limestone dissolution somewhere along the hydrogeological pathway however a wide array of other substratum basalts rhyolites carbonatites ultramafics granites dolomites evaporites can act as potential source of elements involved in the formation of catt this study reports on the evaluation of potential geochemical tracers linking catt to their substratum and unravelling the origin of elements a large database was established from available literature data as well as new data acquired in the frame of this study for a set of modern to recent catt ligurian ophiolites italy the chaine des puys limagne graben and paris basin france reunion island indian ocean jebel oust tunisia four most reliable tracing methods are identified 1 13c and 18o cross plot allows distinguishing epigean min 13c 27 2 max 13c 0 9 mean 13c 12 3 for n 314 from hypogean systems min 13c 4 max 13c 11 7 mean 13c 2 87 for n 198 very low 13c values 4 associated to negative 13c values are specifically indicative of an ultramafic source rock 2 barium and strontium cross plot helps to discriminate different groups of source rocks amongst the hypogean catt i source rocks composed of mixed limestones evaporites and dolomites are characterised by low barium 400 ppm contents ii mafic and granitic source rocks are undifferentiated and display similar barium from 15 to 930 ppm and high strontium 200 ppm contents iii the carbonatite group is characterised by its exceptional high barium and strontium values in epigean catt a pure limestone source rock usually relates to very low barium and strontium contents 50 ppm 3 relatively high beryllium content 30 ppm in catt seems to indicate a pure granitoid source 4 high chromium concentrations 20 ppm are systematically documented in modern catt located on an ultramafic substratum the definition of diagnostic compositional fields for actively forming or recently formed catt is influenced by many factors including water composition water temperature dissolved gas composition and concentration biological activity position in the sedimentary body and early diagenesis in addition to substratum lithology however the results of this study illustrate that despite these many factors the combined use of ba sr be cr 13c and 18o may be valuable to discriminate the rock lithology prevailing in the hydrogeological or palaeo hydrogeological reservoir of catt

sedimentology three dimensional geobody reconstruction and carbon dioxide origin of pleistocene travertine deposits in the ballik area south west turkey the denizli basin in the west anatolian extensional province in western turkey is well known for its numerous travertine occurrences a combined sedimentological diagenetic and geochemical investigation is executed on the ece and faber travertines of the ballk area the largest travertine site in the denizli basin the first aim of this study is the reconstruction of a three dimensional geo model in combination with a detailed sedimentological description from fabric to lithotype lithofacies and geobody scale with a focus on integrating pore typing the second aim involves the delineation of the co2 origin of ancient travertine precipitating waters peloidal phyto and dendritic lithotypes dominate the studied travertines and honeycomb and bacteriform shapes and encrusted bacterial or fungal filaments related to their fabrics suggest a microbial influence the environment of travertine precipitation evolved from dominantly sub aqueous as represented by the sub horizontal and biostromal reed travertine facies to dominantly sub aerial in a thin water film resulting in the cascade waterfall and biohermal reed travertine facies a general progradation of the travertine mound is indicated by the occurrence of stacked waterfall travertines this results in sigmoidal clinoforms inside a general mound boundary configuration strontium and oxygen carbon isotope signatures of the travertines point to a mixing mechanism of palaeofluids with deeply originated heavy carbon co2 with lighter carbon co2 of shallow origin these deposits can thus be considered as endogenic travertines carbonates of the lycian nappes acted as main parent carbon source rocks the relative contribution of the lighter carbon isotopes is most likely to have originated from organic matter or soil co2 this study provides a unique three dimensional insight into the ballk travertine architecture that potentially can be used as an analogue for subsurface travertine reservoirs worldwide and illustrates the importance of the combined use of c 13 and sr 87 sr 86 signatures in the delineation of the co2 origin of travertine precipitating waters

ecogeomorphic feedbacks in regrowth of travertine step pool morphology after dam decommissioning fossil creek arizona abstract the linkages between fluvial geomorphology and aquatic ecosystems are commonly conceptualized as a one way causal chain in which geomorphic processes create the physical template for ecological dynamics in streams with a travertine step pool morphology however biotic processes strongly influence the formation and growth of travertine dams creating the potential for numerous feedbacks here we take advantage of the decommissioning of a hydroelectric project on fossil creek arizona where restoration of caco 3 rich baseflow has triggered rapid regrowth of travertine dams to explore the interactions between biotic and abiotic factors in travertine morphodynamics we consider three conceptual frameworks where biotic factors independently modulate the rate of physical and chemical processes that produce travertine dams combine with abiotic factors in a set of feedback loops and work in opposition to abiotic processes such that the travertine step pool morphology reflects a dynamic balance between dominantly biotic constructive processes and dominantly abiotic destructive processes we consider separately three phases of an idealized life cycle of travertine dams dam formation growth and destruction by erosive floods dam formation is catalyzed by abiotic factors e g channel constrictions and bedrock steps and biotic factors e g woody debris and emergent vegetation from measurements of changes over time in travertine thickness on a bedrock step we find evidence for a positive feedback between flow hydraulics and travertine accrual measurements of organic content in travertine samples from this step show that algal growth contributes substantially to travertine accumulation and suggest that growth is most rapid during seasonal algal blooms to document vertical growth of travertine dams we embedded 252 magnets into nascent travertine dams along a 10 km stretch of river growth rates are calculated from changes over time in the magnetic field intensity at the dam surface at each magnet we record a range of hydraulic and travertine composition variables to characterize the dominant mechanism of growth abiotic precipitation algal growth trapping of organic material or in situ plant growth we find 1 rapid growth of travertine dams following flow restoration averaging more than 2 cm year 2 growth rates decline downstream consistent with loss of dissolved constituents because of upstream travertine deposition but also parallel to a decline in organic content in dam surface material and a downstream shift in dominant biotic mechanism 3 biotic mechanisms are associated with faster growth rates and 4 correlations between hydraulic attributes and growth rates are more consistent with biotic than abiotic controls we conclude that the strong influence of living organisms on rates of travertine growth coupled with the beneficial effects of travertine on ecosystem dynamics demonstrate a positive feedback between biology and geomorphology during our two year study period erosive flood flows occurred causing widespread removal of travertine the temporal distribution of travertine growth and erosion over the study period is consistent with a bimodal magnitude frequency relation in which growth dominates except when large infrequent storms occur this model may be useful in other systems where biology exerts strong controls on geomorphic processes

dissected hydrologic system at the grand canyon interaction between deeply derived fluids and plateau aquifer waters in modern springs and travertine geochemical study of water and gas discharging from the deeply incised aquifer system at the grand canyon arizona provides a paradigm for understanding complex groundwater mixing phenomena and quaternary travertines deposited from cool springs provide a paleohydrologic record of this mixing geochemical data show that springs have marked compositional variability those associated with active travertine accumulations deeply derived endogenic waters are more saline richer in co2 and elevated in 87sr 86sr relative to springs derived dominantly from surface recharge of plateau aquifers epigenic waters endogenic waters and associated travertine are preferentially located along basement penetrating faults we propose a model whereby deeply derived fluids are conveyed upward via both magmatism and seismicity our model is supported by 1 gas analyses from spring waters with high he ar and he n2 and 3he 4he ratios indicating the presence of mantle derived he 2 large volumes of travertine and co2 rich gases in springs recording high co2 fluxes and 3 87sr 86sr in these springs that indicate circulation of waters through precambrian basement geochemical trends are explained by mixing of epigenic waters of the colorado plateau aquifers with different endogenic end member waters in different tectonic subprovinces endogenic waters are volumetrically minor but have significant effects on water chemistry they are an important and largely unrecognized component of the hydrogeochemistry and neotectonics of the southwestern united states

multidisciplinary characterization of the buried travertine body of prima porta central italy abstract a buried travertine deposit identified in a well at prima porta to the north west of rome italy was investigated using a multidisciplinary approach that included stable isotope geochemistry mineralogy petrography and radiometric dating the travertine body is located just along the western boundary of the tiber valley a morpho tectonic depression of extensional origin it is associated with the rise of a deep seated hypothermal saline co2 rich fluid the depositional environment was inferred by the macroscopic features of core and microfacies analysis which suggested that travertine deposition was associated with a low to moderate energy environment such as gently dipping shallow pools on low angle terraced slopes a hydrothermal system characterised by long circulation paths at depth and deeply derived co2 dominated fluids are supported by geochemical analyses according to radiometric dating travertine deposition occurred from between 53 5 10 ka to 24 2 4 7 ka the activation of the travertine depositing spring was probably coeval with the wettest climatic conditions occurring during mis3 whereas the end of deposition coincides with the cold and arid phase of the last glacial maximum

a late miocene early pliocene chain of lakes fed by the colorado river evidence from sr c and o isotopes of the bouse formation and related units between grand canyon and the gulf of california we report strontium isotopic results for the late miocene hualapai limestone of the lake mead area arizona nevada and the latest miocene to early pliocene bouse formation and related units of the lower colorado river trough arizona california nevada together with parallel oxygen and carbon isotopic analyses of bouse samples to constrain the lake overflow model for integration of the colorado river sr isotopic analyses on the basal 1 5 cm of marl in particular along a transect over a range of altitude in the lowest altitude basin that contains freshwater brackish and marine fossils document the 87 sr 86 sr of first arriving bouse waters results reinforce the similarity between the 87 sr 86 sr of bouse formation carbonates and present day colorado river water and the systematic distinction of these values from neogene marine sr basal bouse samples show that 87 sr 86 sr decreased from 0 7111 to values in the range 0 7107 0 7109 during early basin filling 87 sr 86 sr values from a recently identified marl in the las vegas area are within the range of bouse sr ratios 87 sr 86 sr values from the hualapai limestone decrease upsection from 0 7195 to 0 7137 in the approach to a time soon after 6 ma when hualapai deposition ceased and the colorado river became established through the lake mead area bouse formation 18 o values range from 12 9 to 1 0 vienna pee dee belemnite vpdb and 13 c between 6 5 and 3 4 vpdb negative 18 o values appear to require a continental origin for waters and the trend to higher 18 o suggests evaporation in lake waters sr and stable isotopic results for sectioned barnacle shells and from bedding planes of the marine fish fossil colpichthys regis demonstrate that these animals lived in saline freshwater and that there is no evidence for incursions of marine water either long lived or brief in duration lack of correlation of sr and o isotopic variations in the same samples also argue strongly against systematic replacement of sr in bouse carbonates after deposition our results reinforce the conclusion that the bouse formation was deposited in a descending series of basins connected by overflow of colorado river water the hualapai limestone records a separate and earlier lake that may have been progressively influenced by colorado river water as the time of river integration approached

growth of fissure ridge travertines from geothermal springs of denizli basin western turkey fissure ridge travertines grown from geothermal springs of denizli basin southwestern turkey are investigated through stratigraphic structural geochemical and geochronological methods with the aim of understanding the growth of these elongate mound shaped structures two main types of travertine deposits are recognized 1 bedded travertines which grew as flowstone on sloping surfaces and form the bulk of fissure ridges and 2 banded travertines which grew as veins within the bedded travertine chiefly along its central feeding conduit stratigraphic and structural observations shed light on the bedded banded travertine relationships where the banded features grew through successive accretion phases crosscutting the bedded travertine or forming sill like structures the bedded and banded travertines alternated their growth as demonstrated by complicated crosscutting relationships and by the upward suture in places of banded travertine by bedded travertine that was in turn crosscut by younger banded travertine the bedded travertine is often tilted away from the central axis of the fissure ridge thus leaving more room for the central banded travertine to form u series ages confirm the bedded banded travertine temporal relationships and show that the growth of the studied fissure ridges lasted up to several tens of thousands of years during quaternary time the banded travertine was deposited mainly during cold events possibly in coincidence with seismic events that might have triggered the outflow of deep geothermal fluids c and o stable isotope and rare earth element data indicate a shallow feeding circuit for the studied structures with a fluid component deriving from a deeper geothermal circuit a crack and seal mechanism of fissure ridge growth is proposed modulated by the interplay of local and regional influencing factors and mechanisms such as geothermal fluid discharge paleoclimate tectonics and the progressive tilting of bedded travertine limbs over a soft substratum creating the necessary space for the central veins to grow

aqueous and isotope geochemistry of mineral springs along the southern margin of the tibetan plateau implications for fluid sources and regional degassing of co2 springs issuing from different faults and shear zones along the crest of the himalayas tap three different levels of crust beneath the tibetan plateau from structurally highest to lowest these are the tingri graben the south tibetan detachment system stds and the ama drime massif adm the aqueous chemistry reflects water rock interactions along faults and is consistent with mapped rock types major ion chemistry and calculated temperatures indicate that spring waters have circulated to greater depths along the n s trending faults that bound the tingri graben and ama drime detachment add compared to the stds suggesting that these structures penetrate to greater depths springs have excess co2 n2 he and ch4 compared to meteoric water values implying addition from crustal sources the 3he 4he ratios range from 0 018 to 0 063 ra and are consistent with a crustal source for he the 13c values of dissolved inorganic carbon dic and co2 gas range from 5 5 to 3 8 and 13 1 to 0 3 versus peedee belemnite respectively sources of carbon are evaluated by calculating isotopic trajectories associated with near surface effervescence of co2 positive 13c values of the tingri graben and stds springs are consistent with decarbonation of marine carbonates as the source of co2 negative values for the add springs overlap with mantle values but are best explained by metamorphic devolatilization of reduced sedimentary carbon the 15n values of n2 range from 2 2 to 2 1 versus air and are explained by mixtures of air derived nitrogen metamorphic devolatilization of sedimentary nitrogen and nitrogen from near surface biogenic processes co2 flux is estimated by scaling from individual springs 105 mol a 1 per spring to extensional structures across the southern limit of the tibetan plateau and likely contributes between 108 and 1011 mol a 1 up to 10 to the global carbon budget

controls on sr isotopic evolution in lacustrine systems eocene green river formation wyoming abstract strontium isotopes from lacustrine carbonates record detailed weathering histories of exposed bedrocks and thus are potentially useful for understanding interactions between tectonics and climate that may be driven by local or regional factors in basin scale hydrologic systems we combine extensive 87 sr 86 sr and 18 o datasets from the green river formation in order to identify environmental factors driving the evolution of sr concentration and isotopic composition in lacustrine systems through the use of sr mass balance modeling two models are developed the first tests the effect of drainage capture that drove a constant volume lake from balance filled to overfilled conditions and is applied to the laney member of the green river formation the second model focuses on lacustrine evolution in response to changing the concentration composition and mass of water influx in a variable size sr reservoir lake this model is applied to the wilkins peak member of the green river formation 87 sr 86 sr ratios are correlated with 18 o values only during the laney member when both are readily explained by a common forcing mechanism drainage capture modeling of sr isotope compositions and concentrations indicates a short residence time for sr 10 3 10 4 years or less in both balance overfilled and underfilled phases of the green river formation lacustrine system this in turn suggests that paleo lacustrine sediments in most lakes can preserve sr isotope records with high resolution 10 2 years timescales rates of sr sequestration in carbonate are shown to have a strong influence on lacustrine sr concentration and high sr concentrations of lacustrine carbonate consistent with high salinity are observed in the underfilled wilkins peak member and the balance filled tipton and lower laney members in the laney member 87 sr 86 sr mass balance modeling results provide additional support for previous interpretations that the introduction of a large drainage system produced an isotopic shift across the lower laclede upper laclede boundary major drainage reorganization is not required to drive high variability in 87 sr 86 sr ratios however modeling shows that variability in 87 sr 86 sr ratios of 0 004 observed in the wilkins peak member can be explained by change in the characteristics of intrabasinal water sources during highstand vs lowstand conditions

a newly emerged august 2013 artificially triggered fumarole near the fiumicino airport rome italy abstract early in the morning of 24 august 2013 following by hours the drilling of a shallow borehole in the same spot a new fumarole producing emissions of co2 rich gas water and mud suddenly appeared at a crossroad along the fenced area of the fiumicino international airport of rome italy similar episodes have been scientifically documented or simply reported in recent and past years to understand why gases are easily entrapped in the shallow subsurface of the fiumicino area we used five borehole cores drilled by us analyzed the stratigraphy of these and other nearby cores acquired a 2d seismic refraction tomogram and performed chemical and isotopic analyses of water samples collected from aquifers intercepted by two drilled boreholes our boreholes were realized with proper anti gas measures as while drilling we recorded the presence of pressurized gases at a specific permeable gravel level results show that in the study area gases become mainly entrapped in a mid pleistocene gravel horizon at about 40 50 m depth this horizon contains a confined aquifer that stores the endogenous upwelling gases the gravel is interposed between two silty clayey units the lower unit very hard and overconsolidated is affected by fractures that allow ascending gases to bypass the otherwise impermeable shale permeate the gravel and dissolve into the aquifer in contrast the upper unit is impermeable to fluids and seals the gas pressurized aquifer which therefore constitutes a source of hazard during human activities such as well drilling quarrying and various building related excavations as the stratigraphy of the fiumicino area is very common in large portions of the densely populated roman area and as the adjacent volcanic districts are hydrothermally active we conclude that phenomena similar to that observed at fiumicino could again occur both at fiumicino and elsewhere in the surrounding region as a prompt confirmation of our conclusion we signal that while writing this paper new artificially triggered degassing phenomena occurred off fiumicino in connection with the construction of the new harbor

evidence for the younger dryas climatic event in southeast asia abstract this article reviews evidence for the younger dryas climatic event from the limited data available from mainland and island southeast asia and from deep sea cores from the region data from highland indonesia and regional deep sea cores suggest a climatic reversal at the time of the younger dryas may be more widely detectable with finer resolution pollen analysis and additional radiocarbon dating but it should be remembered that dates of this age cannot be calibrated locations are suggested in the region where more sites and finer resolution analysis is needed before definite statements on the younger dryas can be made at present the best evidence for its occurrence comes from one sumatran pollen diagram but even that is very tentative

growth of a pleistocene giant carbonate vein and nearby thermogene travertine deposits at semproniano southern tuscany italy estimate of co2 leakage abstract a giant carbonate vein 50 m thick fissure ridge travertines and nearby travertine plateaus in the semproniano area mt amiata geothermal field southern tuscany italy are investigated through a multidisciplinary approach including field and laboratory geochemical analyses u th geochronology c nd o and sr isotope systematics ree abundances and fluid inclusion microthermometry the main aim of this work is to understand 1 modes and rates for the growth of the giant vein and nearby travertine deposits within a quaternary volcano tectonic domain 2 implications in terms of the co 2 leakage and 3 possible relationships with quaternary paleoclimate and hydrological oscillations results show that the giant vein was the inner portion of a large fissure ridge travertine and grew asymmetrically and ataxially through repeated shallow fluid injections between 650 and 85 ka with growth rates in the 10 2 10 3 mm a order the giant vein developed mainly during warm humid interglacial periods partially overlapping with the growth of nearby travertine plateaus estimated values of co 2 leakage connected with the vein precipitation are between about 5 10 6 and 3 10 7 mol a 1 km 2 approximately representing one millionth of the present global co 2 leakage from volcanic areas temperature estimates obtained from o isotopes and fluid inclusion microthermometry indicate epithermal conditions 90 50 c for the circulating fluid during the giant vein growth with only slight evidence of cooling with time geochemical and isotope data document that the travertine deposits formed mainly during pleistocene warm humid periods within a tectonically controlled convective fluid circuit fed by meteoric infiltration and maintained by the regional geothermal anomaly hosted by the carbonate reservoir of the mt amiata field

fossil travertine system and its palaeofluid provenance migration and evolution through time example from the geothermal area of acquasanta terme central italy abstract the geothermal area of acquasanta terme has often been studied for its active and fossil travertine deposits to elucidate fluid origin geodynamic and hydrological setting even though present day thermal springs are usually used to obtain most information the three travertine terraces bordering the tronto river contain a plethora of information a combination of elemental and isotope analyses 18o 13c and 87sr 86sr ratio fluid inclusion microthermometry and u th dating is used to verify the hydrogeology and its timing these analyses point out two fluid reservoirs with distinctly different fluids one with low salinity of 0 7 wt nacl eq and another with 28 5 wt nacl eq which corresponds to the fluid composition of present day spring fluids furthermore it is demonstrated that geothermal sources were intermittently active in the past 221 ka mainly during uneven numbered marine isotope stages which are related to humid interglacial periods and resulted in three different travertine terraces around 210 5 126 5 and 36 5 ka accordingly an uplift rate for this area could be estimated at around 1 mm ka the fluids were tapped at a depth of approximately 3 km in the tectonized cataclastic fraction of the triassic anidriti di burano formation the calcare cavernoso formation and are originally meteoric based on geochemical evidence of a uniform 87sr 86sr ratio of 0 707914 0 00019 and a 18oaragonite value of 11 90 0 34 which has been depressed by elevated precipitation temperatures between 22 2 and 50 c the characterization and dating of fossil travertine deposits gives valuable data providing insights in long term fluid flow and orogenic uplift rates adding valuable information to present day spring fluid characterization

continental smokers couple mantle degassing and distinctive microbiology within continents abstract the discovery of oceanic black and white smokers revolutionized our understanding of mid ocean ridges and led to the recognition of new organisms and ecosystems continental smokers defined here to include a broad range of carbonic springs hot springs and fumaroles that vent mantle derived fluids in continental settings exhibit many of the same processes of heat and mass transfer and ecosystem niche differentiation helium isotope 3he 4he analyses indicate that widespread mantle degassing is taking place in the western u s a and that variations in mantle helium values correlate best with low seismic velocity domains in the mantle and lateral contrasts in mantle velocity rather than crustal parameters such as gps proximity to volcanoes crustal velocity or composition microbial community analyses indicate that these springs can host novel microorganisms a targeted analysis of four springs in new mexico yield the first published occurrence of chemolithoautotrophic zetaproteobacteria in a continental setting these observations lead to two linked hypotheses that mantle derived volatiles transit through conduits in extending continental lithosphere preferentially above and at the edges of mantle low velocity domains high co2 and other constituents ultimately derived from mantle volatiles drive water rock interactions and heterogeneous fluid mixing that help structure diverse and distinctive microbial communities

springwater provenance and flowpath evaluation in blue lake bonneville basin utah abstract water in utah and nevada is important for agriculture municipal use solute transport and ecosystem preservation large spring wetland systems occur on the playa margin of the bonneville basin including blue lake 15 km south of the bonneville salt flats on the utah nevada state border large spring systems have historically been studied as water budgets don t apparently balance from direct mountain front recharge nelson and mayo 2014 gardner and heilweil 2014 and others blue lake is no exception prior studies here have suggested discharge rates 0 04 0 05 km3 yr louderback and rhode 2009 greater than expected for modelled recharge in the surrounding mountain range 0 03 km3 yr three hypothesized recharge mechanisms for blue lake are tested mountain front recharge interbasinal groundwater flow and infiltration from historic lake bonneville remote sensing suggests that a conservative estimate of blue lake discharge constitutes 50 64 of modelled mountain front recharge flint et al 2011 major ions 18o 2h dissolved gases 14c 3he 4he ne ar kr xe and trace elements sr and 87sr 86sr isotopes comprehensively constrain recharge conditions water rock interactions flowpaths and groundwater provenance of this large spring system 14c signatures suggest that blue lake discharge has a transit time between 5 600 and 12 200 years older than that of fish springs noble gas concentrations in blue lake water suggest an elevated recharge temperature greater than 19 c and low salinity indicating a deep water table and high geothermal gradient in the recharge area 87sr 86sr ratios of playa margin springs are elevated from that of mid playa groundwaters springwaters from the adjacent mountain range and alluvial fill groundwater from the valley directly south of blue lake playa margin spring sr isotope values 0 713 0 714 are most similar to direct runoff from the deep creek range granodiorite outcrop 0 713 interbasinal groundwater flow in combination with mountain front recharge is best supported by chemical data rather than mountain front recharge alone or the slow discharge of regional aquifers recharged by lacustrine infiltration from lake bonneville

ages of travertine deposits in eastern grand canyon national park arizona abstract travertine deposits in eastern grand canyon national park arizona are inferred to have formed under conditions of effective wetness that were greater than present uranium series dating of 17 samples indicates that the deposits formed at about 15 000 71 000 111 000 171 000 and 338 000 yr b p intervals of travertine deposition are essentially contemporaneous with dated high paleolake levels montane glacial maxima and high paleowater table levels from several great basin localities

lithospheric dismemberment and magmatic processes of the great basin colorado plateau transition utah implied from magnetotellurics 1 to illuminate rifting processes across the transition zone between the extensional great basin and stable colorado plateau interior we collected an east west profile of 117 wideband and 30 long period magnetotelluric mt soundings along latitude 38 5 n from southeastern nevada across utah to the colorado border regularized two dimensional inversion shows a strong lower crustal conductor below the great basin and its transition zone in the 15 35 km depth range interpreted as reflecting modern basaltic underplating hybridization and hydrothermal fluid release this structure explains most of the geomagnetic variation anomaly in the region first measured in the late 1960s hence the transition zone while historically included with the colorado plateau physiographically possesses a deep thermal regime and tectonic activity like that of the great basin the deep crustal conductor is consistent with a rheological profile of a brittle upper crust over a weak lower crust in turn on a stronger upper mantle jelly sandwich model under the incipiently faulted transition zone the conductor implies a vertically nonuniform mode of extension resembling early stages of continental margin formation colorado plateau lithosphere begins sharply below the western boundary of capitol reef national park as a resistive keel in the deep crust and upper mantle with only a thin and weak moho level crustal conductor near 45 km depth several narrow steep conductors connect conductive lower crust with major surface faulting some including modern geothermal systems and in the context of other great basin mt surveying suggest connections between deep magma sourced fluids and the upper crustal meteoric regime the mt data also suggest anisotropically interconnected melt over a broad zone in the upper mantle of the eastern great basin which has supplied magma to the lower crust consistent with extensional mantle melting models and local shear wave splitting observations we support a hypothesis that the transition zone location and geometry ultimately reflect the middle proterozoic suturing between the stronger yavapai lithosphere to the east and the somewhat weaker mojave terrane to the west we conclude that strength heterogeneity is the primary control on locus of deformation across the transition zone with modulating force components

travertine deposits from along the south tibetan fault system near nyalam tibet a newly investigated travertine deposit in southern tibet provides a window into holocene hydrological geomorphic and climatic processes near the boundary of the tibetan plateau and high himalaya travertine deposited as a result of the degassing of co 2 rich groundwater as it emerges on the earth s surface is in many cases formed along the trace of major crustal scale faults in primarily extensional tectonic regimes a travertine platform measuring roughly 1 km by 0 5 km exists near the town of nyalam in southern tibet along a major himalayan down to the n normal fault the south tibetan fault system a wide variety of travertine depositional textures and features are recorded in the platform on a series of terraces active travertine deposition was observed from spring mounds and seeps along the base of the platform at the modern river level palaeotemperatures of spring water calculated from 18 o of the travertine range from 9 to 25 c which closely matches the temperatures recorded from modern springs in the area a complex geomorphological landscape records interaction between growing alluvial fans travertine accumulation and a rapidly down cutting river with associated fluvial terraces river incision was contemporaneous with travertine deposition as indicated by cemented fluvial river gravel layers interbedded with travertine high 87 sr 86 sr ratios in the travertine mean of 0 7168 indicate subsurface fluid interaction with radiogenic crystalline rocks of the underlying greater himalaya uranium series ages of the travertine platform range from 5400 a 950 a to 11 600 a 1000 a and indicate a younging progression from higher terraces near the valley wall to lower terraces at present day river level travertine that overlies a river gravel terrace 18 m above river level formed at 11 600 a this date yields a local incision rate of 1 6 mm a 1 consistent with estimated fluvial incision rates in the high himalaya the range of our u series ages coincides with an interval of higher precipitation associated with greater intensity of the indian monsoon which led to elevated spring discharge and carbonate precipitation in this part of the high himalayas

karst hydrology of grand canyon arizona usa summary caves in grand canyon arizona usa fall into two main categories those formed under unconfined conditions and those formed under confined conditions this study focuses on the hydrology and paleohydrology of the confined caves in the redwall muav aquifer where the aquifer is overlain by rocks of the supai group and underlain by the bright angel shale unconfined caves are discussed only in their relation to confined caves discharge for confined groundwater was as it is today primarily from the redwall limestone where it has been incised by the main canyon or its tributaries and where it has converged along a structural low or fault descent of the potentiometric surface or water table over time is recorded by one ore episode and six cave episodes 1 emplacement of cu u ore 2 precipitation of iron oxide in cavities 3 dissolution of cave passages 4 precipitation of calcite spar linings over cave passage walls 5 precipitation of cave mammillary coatings 6 minor replacement of cave wall and ceiling limestone by gypsum and 7 deposition of subaerial speleothems the mammillary episode records the approximate position of the water table when the incision of the canyon was at that level discharge toward spring points has reorganized and adjusted with respect to ongoing canyon and side canyon incision the dissolution of grand canyon confined caves was the result of the mixing of epigene waters with hypogene waters so that undersaturation with respect to calcite was achieved the karst hydrology of grand canyon may be unique compared to other hypogene cave areas of the world

reply to the comment on first records of syn diagenetic non tectonic folding in quaternary thermogene travertines caused by hydrothermal incremental veining by billi et alii abstract in our previous paper billi et al 2017 using field geological observations u th dating and stable isotope analyses we studied two deposits of pleistocene thermogene travertines from tuscany in central italy we concluded our study 1 warning that the common stratigraphic concept of travertine being a sedimentary succession with age younging from bottom to top is not always correct 2 demonstrating that caco3 mineralization and veins can develop within the travertines after their formation with this syn diagenetic process being able to modify the continuous bottom up age evolution and 3 showing that this post depositional mineralization veining process can not only modify the temporal succession but also deform and change the initial depositional travertine structure and its petrophysical properties these conclusions could potentially make the interpretation of a travertine series more difficult than commonly thought alcicek et alii questioned our conclusions claiming that the travertine structures that we observed in tuscany and interpreted as post depositional features should have been interpreted in analogy to similar structures from travertines elsewhere as primary structures although we recognize as already thoroughly stated in billi et al 2017 that the travertine depositional post depositional processes generally require further studies we reaffirm the validity of our original interpretation at least for the structures analyzed in our previous paper we therefore counter all criticisms by alcicek et alii and conclude by indicating the way forward to further explore the depositional and post depositional processes of thermogene travertines

evolution of fault permeability during episodic fluid circulation evidence for the effects of fluid rock interactions from travertine studies utah usa faults are known to be important pathways for fluid circulation within the crust the transfer properties along faults can evolve over time and space the little grand wash and salt wash normal faults located on the colorado plateau are well known examples of natural co2 leakage systems from depth to surface previous studies dated and established a chronology of co2 enriched fluid source migration along the fault traces and linked the aragonite veins observed close to crystal geyser to co2 pulses however multiple circulation events recorded along a given fault segment deserve to be studied in minute detail in order to unravel the chronology of these events precipitation processes and associated mechanisms a combination of structural geology petrography u th dating oxygen and carbon isotope analysis were used to study the fault related co2 enriched paleo circulations in order to build a conceptual model of co2 circulation along the faults this study resulted in the precise descriptions of the features attesting co2 enriched fluid circulation by a characterization of their relationship and architecture at the outcrop scale these features are witnesses of a large range of circulation sealing mechanisms as well as changes in fluid chemistry and thermodynamic state of the system providing evidence for i the evolution of the fluid through a pathway from depth to the surface and ii different cycles of fault opening and sealing large circulation events linked with fault opening sealing are observed and calibrated in nature with millennial circulation and sealing time lapses numerical modelling indicates that such sealing timescale can be explained by the introduction of a fault sealing factor that allows modifying permeability with time and that is calibrated by the natural observations

hydrochemical and isotope characteristics of spring water and travertine in the baishuitai area sw china and their meaning for paleoenvironmental reconstruction a method of combining hydrochemical data logging and in situ titrating with measurement of stable carbon and oxygen isotopes was used to reveal the hydrochemical and isotopic characteristics in the baishuitai travertine scenic area of sw china it was found that the travertine forming springs have a very high concentration of calcium and bicarbonate and accordingly very high co2 partial pressures which are not likely to be produced by biological activity in soil alone further analysis of the stable carbon isotopes of the springs shows that the high pressure of co2 is mainly related to an endogenic co2 source that means the baishuitai travertine is endogenic in origin this is contrast to the commonly accepted saying that the travertine deposition in this study simply is a product of warm and humid conditions in a karst ecological environment rapid co2 degassing from the water is triggered by the much higher partial pressures in water than that of the surrounding air consequently as the waters flow downstream of the spring the ph increases the waters become supersaturated with respect to calcite and travertine is deposited the preferential release of 12co2 to the atmosphere results in a progressive increase of travertine 13c downstream this is concluded with a preliminary discussion of variation in travertine forming water temperatures according to differences in stable oxygen isotopic compositions of the travertine formed in different epochs at baishuitai it was found that the change in water temperature is as high as 13 c i e from 23 c at about 2500 years b p to 10 c at present this may mainly reflect that the effect of geothermal source on water temperature is decreasing the problems involved in paleoenvironmental reconstruction with endogene travertine are also discussed they are the impacts of dead carbon in radiocarbon dating and the enrichment in 13c of travertine by endogenic co2 and degassing of co2 from water which has to be considered in paleovegetation reconstruction when using 13c data of the endogene carbonate deposits

travertines depositional morphology and the bacterially constructed constituents abstract investigation of travertine accumulations throughout central italy and the west central u s has shown that the carbonate is precipitated in response to both inorganic and organic processes individual deposits range up to 85 m thick and hundreds of square kilometers in areal extent all of the carbonate is low magnesian calcite water chemistry temperature and morphology of the accumulation greatly influence the constituents comprising these deposits harsh environmental situations favor inorganic deposits while increasingly more moderate conditions result in the formation of a greater abundance of organically precipitated material morphological variations of travertine deposits recognized include 1 waterfall or cascade 2 lake fill 3 sloping mound fan or cone 4 terraced ound and 5 fissure ridge gross morphology internal stratification and constituents comprising these deposits vary systematically depending upon the type of accumulation and chemistry of the waters bacterially precipitated calcite forms a large percentage of the carbonate in many travertine accumulations exceeding 90 of the framework grains comprising some of the lake fill deposits bacteria are among the first taxa to inhabit and reproduce in harsh spring environments and produce a variety of fascinating constituents the bacteria are primarily rods generally 0 2 m in diameter and less than 1 0 m in length the rods readily decay resulting in calcite crystals loaded with micropores the basic building block of bacterially constructed travertine is a clump of bacteria averaging 20 m in diameter enclosed in a single crystal of calcite aggregates of these crystals produce a variety of deposits including 1 crudely laminated carbonate mud 2 finely laminat d layers of mud 3 intraclasts 4 foam rock and 5 shrubs the shrubs are most striking commonly forming layers 1 3 cm thick but also producing bacterial pisoids at some locales bacterial stromatolites composed of layers of shrubs alternating with finely laminated layers of bacterial mud comprise essentially the entire deposit the shrub layers are the result of flourishing summer growth of bacteria and furthermore show remarkable daily laminae 0 1 0 5 mm thick the importance of bacteria in the formation of travertine and their universally recognized abundance in modern sediments provides an impetus for a reexamination of the role of bacteria in the origin of other types of ancient deposits

using fossil spring deposits in the death valley region usa to evaluate palaeoflowpaths spring deposits reveal the timing and environment of past groundwater discharge herein however the potential for fossil spring deposits to infer water sources and palaeoflowpaths through trace elements and stable and radiogenic isotopes is examined past discharge 70 to 285 ka in the tecopa basin in the death valley region of southeastern california is represented by tufa deposits including mounds pools cemented ledges and rare calcite feeder veins 18o values indicate that spring discharge was a mixture of far travelled regional water with a significant and perhaps dominant contribution of local recharge on a nearby range front and alluvial pediment rather than simply representing an elevated regional water table 13c values indicate regional water had a high tds whereas solute data imply low overall solute contents consistent with dilution by a large component of local recharge radiogenic isotope data u series 87sr 86sr for tufa indicate that siliciclastic rocks a regional aquitard interacted with discharging water to access this aquitard regional flow was probably partitioned into a permeable north south damage zone of a north south range bounding fault along the foot of the resting spring range which ultimately controlled the location of groundwater discharge existing models for modern discharge in the tecopa basin by contrast call upon westward interbasin flow in carbonate rocks from the spring mountains through the intervening and nearly perpendicular nopah and resting spring ranges understanding the controls on regional groundwater flow is critical in this and other arid regions where water is by definition a scarce resource thus although it is a case study this report highlights a fruitful approach to palaeohydrology that can be widely applied copyright 2007 john wiley sons ltd

geobody architecture genesis and petrophysical characteristics of the budakalasz travertines buda hills hungary subsurface pre salt lower cretaceous reservoir systems encountered offshore brazil and angola that consist of porous continental carbonates are difficult to access because of the limited core material that is under concession therefore it is important to study comparable continental carbonate analogues such as travertines and lacustrine carbonates that potentially possess similar porosity and permeability characteristics the budakalasz pleistocene travertines buda hills hungary have been studied from a sedimentological geochemical and reservoir properties point of view in order to understand their formation petrophysical properties and 3d reservoir architecture the three dimensional geobody architecture of the budakalasz travertines illustrates the potential complexity of kilometre scale continental carbonate systems heterogeneous low angle sloping travertine lobes consisting of terrace slope smooth slope and reed facies are covered by a lime mudstone dominated gastropod and charophyte rich marsh pool facies the observed facies represent a change from a subaerial travertine to a palustrine to lacustrine system reflecting the ceasing of the system due to tectonic uplift the dominant paleo flow direction of the sloping lobes was towards the danube depression with several subordinate flow systems identified the srco isotope geochemical signatures reflect travertine precipitation at ambient to superambient temperatures from meteoric derived fluids with a mixed co2 origin of the marine carbonate substrate rocks a potential atmospheric and a soil derived component although the uniform signatures of the stable oxygen and carbon isotopes in addition to petrographic observations suggest partial diagenetic isotopic resetting the primary isotope trends seem to have been preserved a reservoir oriented facies evaluation in the three dimensional geobody frame of the budakalasz carbonates based on porosity and permeability core plug analyses reveals their heterogeneous nature terrace smooth slope and marsh pool facies have considerable porosities of 5 15 while the porosity of the reed facies may reach up to 27 permeability of all facies is strongly anisotropic mainly controlled by a better connectivity along layer parallel primary pores the reconstruction of the 3d geobody architecture of the budakalasz lobe complex coupled to its geochemical and petrophysical properties provides a unique dataset that contributes in understanding fossil travertine systems

soil gas distribution in the main coseismic surface rupture zone of the 1980 ms 6 9 irpinia earthquake southern italy soil gas measurements of different gas species with different geochemical behaviors were performed in the area of the pecore plain a 200 m 300 m sized fault bounded extensional basin located in the northern mount marzano massif in the axial belt of the southern apennine chain the pecore plain area was affected by coseismic surface faulting during the ms 6 9 1980 irpinia earthquake the strongest and most destructive seismic event of the last 30 years in southern italy the collected data and their geostatistical analysis provide new insights into the control exerted by active fault segments on deep seated gas migration toward the surface the results define anomalies that are aligned with the nw se trending coseismic rupture of the 1980 earthquake along the western border of the plain as well as along the southern border of the plain where a hidden e w striking fault is inferred geospatial analysis highlights an anisotropic spatial behavior of 222rn along the main nw se trend and of co2 along the e w trend this feature suggests a correlation between the shape and orientation of the anomalies and the barrier conduit behavior of fault zones in the area furthermore our results show that gas migration through brittle deformation zones occurs by advective processes as suggested by the relatively high migration rate needed to obtain anomalies of short lived 222rn in the soil pores

tectonic control on travertine and calcareous tufa deposition in a low temperature geothermal system sarteano central italy this paper presents an integrated study directed toward an understanding of the tectonic control on the hydrothermal circulation and resulting deposition of middle late pleistocene travertine in a low temperature geothermal field of southern tuscany located in the sarteano area central italy the study area is characterized by thermal springs c 25 c and related continental carbonate deposits structurally controlled by sw ne trending oblique to strike slip faults dissecting previous normal faults sedimentological stratigraphical data and 230 th 234 u radiometric age determination for the travertine indicate that continental carbonates were deposited in a tectonically controlled perched spring system from 268 22 ka at least to the present the hydrothermal system is and was characterized by meteoric waters with a minor contribution from fluids of deeper origin meteoric waters infiltrated to depth through tectonically damaged zones of mesozoic and cenozoic carbonate rocks and overheated as a result of localized anomalous geothermal gradient then fluids enriched in bicarbonate sulphate moved up along highly fractured rock masses at the intersection between strike slip faults and normal faults this paper highlights the use of continental carbonates in the reconstruction of palaeohydrothermal systems in terms of the location of the main conduits for hydrothermal fluid flow age of faulting and physical properties of hydrothermal fluids

hydrogeochemistry of the middle rio grande aquifer system fluid mixing and salinization of the rio grande due to fault inputs abstract deeply derived fluids influence river and groundwater hydrochemistry at the socorro constriction in the central new mexico rio grande rift new hydrochemical transects in the rio grande rift provide three dimensional perspectives on sources contributing to surface and groundwaters in addition to abrupt salinity increases in the rio grande major and trace ion chemistry 18o d 13c 87sr 86sr 3h and 3he 4he variations in springs and wells across the rift are best explained by mixing of deeply derived endogenic fluids containing both mantle and crustal inputs with shallow groundwater endogenic fluids ascend along rift bounding and intra rift faults and can cause increased salinity accompanied by an increase in metals and overall degradation of water quality our data reinforce models that attribute a downstream increase in salinity to geological not agricultural influences hydrochemical mixing of endogenic waters along faults in shallow aquifers has a major influence on groundwater and surface water quality and variability in arid tectonically active regions with important ramifications for water management

tufa and travertines of southern italy deep seated fault related co 2 as the key control in precipitation continental carbonates of quaternary age in southern italy commonly exhibit the facies of calcareous tufa often reported as related to shallow aquifers fed by meteoric waters and to organic processes a close spatial relationship exists between the mappable tufa deposits and major quaternary extensional faults with respect to the ca mg hco3 composition of limestone aquifers springs tufa depositing springs exhibit higher salinity and alkalinity are slightly warmer have lower ph and are enriched in so4 and co2 their d 13 c values are systematically positive and compatible with a deep seated carbon source a clear input of soil derived organic carbon is indicated only for small non mappable tufas deposited by perched springs the dataset indicates that the large tufa deposits owe their origin to a supplementary source of co2 advected by degassing through active faults as a necessary prerequisite for inducing a rise of total dissolved salts and alkalinity meteoric waters that have come from a shallow aquifer are able to precipitate only limited amount of carbonates

follow the water connecting a co2 reservoir and bleached sandstone to iron rich concretions in the navajo sandstone of south central utah usa concretions with thick iron oxide cemented rinds and lightly cemented iron poor sandstone cores are abundant within the navajo sandstone near the southeast fl ank of the escalante anticline utah united states previous workers suggested the spheroidal concretions as analogs for martian blueberries hematite concretions and linked the origin of concretions and bleaching of the navajo sandstone to the buoyant rise of hydrocarbons toward anticlinal crests we measured azimuths of 163 pipe like pipy joint associated concretions and those of 58 comet tails that extend from some spherical concretions both data sets have vector magnitudes 90 and subparallel southeast directed resultant vectors our data indicate that groundwater transported and deposited iron over a fl ow path that spanned more than 100 km from the anticlinal crest to the colorado river buoyant fl uids could not have transported iron from bleached rock to sites of concretion growth however because iron moved downdip we propose that iron was transported southeastward by reducing groundwater that fl owed through a co 2 and methane charged reservoir within the escalante anticline iron rich carbonates precipitated during co 2 degassing after methane was fl ushed from the aquifer microaerophiles oxidized fe 2 in concretions dissolving the carbonates and forming the iron oxide rich rinds and iron poor cores these concretions defi ne the fl ow direction and geochemical evolution of a paleoaquifer this approach could be used to follow the water on other planets

a multi methodological approach to reconstruct the configuration of a travertine fissure ridge system the case of the cukor quarry suttő gerecse hills hungary abstract travertines are continental carbonates that precipitate from spring waters mainly due to co2 degassing they are widely quarried as building stone which has led to numerous often abandoned travertine quarry outcrops these and other outcrops however merely represent the surface expressions of the complex architecture of travertine bodies and their deep rooted feeding systems integration of field observations and geochemical analyses with crucial subsurface geophysical data is required in order to fully understand travertine systems and their relationship to the local geological framework such a multi methodological approach is illustrated here for the case of the abandoned cukor quarry radio magnetotelluric rmt and electrical resistivity tomography ert surveys provide unique insights into local tectonics geobody architecture and the topography preceding travertine deposition altogether the lens shaped isolated domal geobody with spring proximal lithofacies and subvertical bedding in addition to the contrasting geochemistry and age with surrounding travertine enabled the unequivocal reconstruction of the dismantled cukor fissure ridge this study illustrates the high potential of this multi methodological approach on poorly exposed strongly weathered quarried and tectonically deformed travertine bodies and provides information on the complex feeding system beneath travertine deposits their reconstruction can be interpreted in light of the neo tectonic expression of regional uplift helps to complete the regional tectonic history and provides insights into older landscapes that lack preservation or would no longer be immediately recognized at the surface

carbonic springs as distal manifestations of geothermal systems highlighting the importance of fault pathways and hydrochemical mixing example from the jemez mountains new mexico abstract we examine a series of carbonic warm and hot springs in northern new mexico usa 1 tierra amarilla springs 2 penasco springs and 3 soda dam jemez and indian hot springs spring geochemistry is compared to waters from the valles caldera geothermal system and to groundwater in nearby sedimentary aquifers multiple hydrochemical tracers are applied to quantitatively evaluate flow paths and mixing at varying distances from the caldera we test three hypotheses for source and transport of waters to tierra amarilla and penasco springs san juan basin origin meteoric flow from the nacimiento mountains and or influence from the valles caldera geothermal system geochemically carbonic spring groups are distinct from meteoric and sedimentary aquifer waters based on isotopes of he and sr and concentrations of cl so4 li and b we interpret these carbonic springs to be distal manifestations of fluid circulation along faults with a mixture of valles caldera geothermal waters local meteoric and paleozoic aquifer waters with the potential for small contributions from the san juan basin aquifers semi confined fault conduits the jemez fault and nacimiento fault systems provide connectivity and help explain geochemical similarities and mixing trends within carbonic spring systems and between these systems and the distal valles caldera in addition penasco springs are interpreted to reflect a component of outflow from the geothermal system that crosses the nacimiento mountain basement block along ne trending faults input of deeply sourced waters can degrade water quality by contributing significant salinity and trace metals to groundwater at distances of 50 km from geothermal systems with faults acting as conduits for subsurface fluid flow