investigating fossil hydrothermal systems by means of fluid inclusions and stable isotopes in banded travertine an example from castelnuovo dell abate southern tuscany italy southern tuscany italy hosts geothermal anomalies with associated widespread co2 gas rich manifestations and active travertine deposing thermal springs geothermal anomalies have been active since the late miocene and have led to the formation of widespread late miocene pleistocene travertine deposits and meso and epithermal mineralizations this study investigates the travertine deposit exposed in the castelnuovo dell abate area of southern tuscany here a fissure ridge type travertine deposit and its feeding conduits currently filled with banded calcite veins i e banded travertine represent a spectacular example of fossil hydrothermal circulation in the peripheral area of the exploited monte amiata geothermal field the castelnuovo dell abate travertine deposit and associated calcite veins were analysed to establish the characteristics of the parent hydrothermal fluids and the age of this circulation the focus of the study was on fluid inclusions rarely considered in travertine studies but able to provide direct information on the physico chemical characteristics of the original fluid uranium thorium geochronological data provided further constraints on the 1 age of tectonic activity 2 age of the hydrothermal circulation and 3 evolution of the monte amiata geothermal anomaly results indicate that brittle deformation nw and se trending normal to oblique slip faults was active during at least the middle pleistocene and controlled a hydrothermal circulation mainly characterized by fluids of meteoric origin and as old as 300 350 ka this is the oldest circulation documented to date in the monte amiata area the fluid chemical composition is comparable to that of fluids currently exploited in the shallow reservoir of the monte amiata geothermal field therefore suggesting that fluid composition has not changed substantially over time these fluids however have cooled by about 70 c in the last 300 350 ka corresponding to a cooling rate of the monte amiata geothermal area of about 20 c 100 ka 1

geochemical study of travertines along middle lower tiber valley central italy genesis palaeo environmental and tectonic implications several travertine deposits dating to the pleistocene outcrop along the tiber valley between orte and rome mineralogically they are mainly composed of calcite various lithofacies stromatolitic phytoclastic and massive were identified and relatively wide ranges of carbon 13c 8 11 to 11 42 vs vpdb and oxygen 18o 22 74 to 27 71 vs vsmow isotope compositions were measured the isotope and chemical compositions of water and free gases in some cases associated with the travertines were also measured carbon isotope data show that several samples fall in the typical range of thermogenic travertine i e linked to the addition of deep inorganic co2 the oxygen isotope composition of the springs associated with the travertine deposits points to travertine precipitation by slightly thermal water of meteoric origin in general these travertines are in association with or close to mineralised groundwaters with slightly acidic ph low thermalism and enrichment in sulphates or sodium chloride and rich co2 gas emissions the origin of which may be linked to decarbonation reactions the travertine bodies are locally connected with crustal structural lineaments favouring the circulation of ascending deep co2 rich fluids conversely some samples show isotopic connotations of meteogenic deposits representing travertines formed mainly from soil biogenic or atmospheric carbon dioxide generally present in shallow groundwater or surface water according to their morphology and isotope data these travertines may be attributed to the sedimentary environment of waterfalls these new geochemical and morphological data are integrated with those already available in the literature regarding the study area and contribute to shedding light on palaeo environmental conditions in western central italy during the quaternary

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

calibration of the calcite water oxygen isotope geothermometer at devils hole nevada a natural laboratory abstract the 18 o of ground water 13 54 0 05 and inorganically precipitated holocene vein calcite 14 56 0 03 from devils hole cave 2 in southcentral nevada yield an oxygen isotopic fractionation factor between calcite and water at 33 7 c of 1 02849 0 00013 1000 ln calcite water 28 09 0 13 using the commonly accepted value of calcite water t of 0 00020 k 1 this corresponds to a 1000 ln calcite water value at 25 c of 29 80 which differs substantially from the current accepted value of 28 3 use of previously published oxygen isotopic fractionation factors would yield a calcite precipitation temperature in devils hole that is 8 c lower than the measured ground water temperature alternatively previously published fractionation factors would yield a 18 o of water from which the calcite precipitated that is too negative by 1 5 using a temperature of 33 7 c several lines of evidence indicate that the geochemical environment of devils hole has been remarkably constant for at least 10 ka accordingly a re evaluation of calcite water oxygen isotopic fractionation factor may be in order assuming the devils hole oxygen isotopic value of calcite water represents thermodynamic equilibrium many marine carbonates are precipitated with a 18 o value that is too low apparently due to a kinetic isotopic fractionation that preferentially enriches 16 o in the solid carbonate over 18 o feigning oxygen isotopic equilibrium

gisp2 oxygen isotope ratios the gisp2 oxygen isotope record with its high resolution detail yields crucial information on past climate change the glacial 18o oscillations of the gisp2 core with their very fast onsets are templates of a prototype oscillation of variable duration with an amplitude of 3 9 the halfway mark of the cold warm transition is reached in 2 years the top is reached in 50 years the 18o time gradient of the leading front is about 7 8 per 100 yr after reaching the top 18o slowly declines by 0 14 per 100 yr the duration of 18o decline varies from a couple of centuries for fast oscillations to about 4000 yr for slower ones the subsequent 18o downturn during the warm cold transition has a 18o time gradient of 3 2 per 100 yr and lasts about 80 yr

stable isotope geochemical study of pamukkale travertines new evidences of low temperature non equilibrium calcite water fractionation abstract in this paper we present the first detailed geochemical study of the world famous actively forming pamukkale and karahayit travertines denizli basin sw turkey and associated thermal waters sampling was performed along downstream sections through different depositional environments vent artificial channel and lake terrace pools and cascades of proximal slope marshy environment of distal slope 13 c travertine values show significant increase from 6 1 to 11 7 pdb with increasing distance from the spring orifice whereas the 18 o travertine values show only slight increase downstream from 10 7 to 9 1 pdb mainly the co 2 outgassing caused the positive downstream shift 6 in the 13 c travertine values the high 13 c values of pamukkale travertines located closest to the spring orifice not affected by secondary processes suggest the contribution of co 2 liberated by thermometamorphic decarbonation besides magmatic sources based on the gradual downstream increase of the concentration of the conservative na k cl evaporation was estimated to be 2 5 which coincides with the moderate effect of evaporation on the water isotope composition stable isotopic compositions of the pamukkale thermal water springs show of meteoric origin and indicate a local meteoric water line of denizli basin to be between the global meteoric water line craig 1961 and western anatolian meteoric water line imsek 2003 detailed evaluation of several major and trace element contents measured in the water and in the precipitated travertine along the pamukkale mm section revealed which elements are precipitated in the carbonate or concentrated in the detrital minerals former studies on the hungarian egerszalok travertine kele et al 2008a b 2009 had shown that the isotopic equilibrium is rarely maintained under natural conditions during calcite precipitation in the temperature range between 41 and 67 c in this paper besides the detailed geochemical analyses along downstream sections we present new evidences of non equilibrium calcite water fractionation in lower temperature range 13 3 to 51 3 c our measurements and calculations on natural hot water travertine precipitations at pamukkale and egerszalok revealed that the 18 o travertine is equal with the 18 o hco3 at the orifice of the thermal springs which means that practically there is no oxygen isotope fractionation between these two phases high rate of co 2 degassing with rapid precipitation of carbonate could be responsible for this as it was theoretically supposed by o neil et al 1969 thus for the determination of the deposition temperature of a fossil travertine deposit we propose to use the water bicarbonate oxygen isotope equilibrium fractionation instead of the water travertine fractionation which can result 8 9 c difference in the calculated values our study is the first detailed empirical proof of o neil s hypothesis on a natural carbonate depositing system the presented observations can be used to identify more precisely the deposition temperature of fossil travertines during paleoclimate studies

radium isotopes alkaline earth diagenesis and age determination of travertine from mammoth hot springs wyoming u s a abstract travertine from active springs former vents and drill core from mammoth hot springs wyoming was analyzed for ra isotopes 226 ra 228 ra other alkaline earth elements mg sr ba and mineralogical composition thermal water also was analyzed travertine presently being deposited contains 3 0 15 3 pci g 226 ra and has a 228 ra 226 ra ratio identical to that in thermal water travertine precipitates mostly as aragonite and experiences a complete diagenetic transformation to calcite within 9 a estimated from 228 ra 226 ra value of youngest completely calcite travertine systematic compositional changes associated with this diagenetic transformation are enrichment of mg and depletion of sr ba and ra apparent mineral water distribution coefficients for mg sr and ba in aragonite and calcite are within the range of those determined experimentally implying near equilibrium conditions and high water rock ratios during travertine diagenesis impure travertine from near the base of the travertine section in the u s geological survey y 10 drill hole at 72 9 m depth has a 230 th 234 u isochron age of 7700 440a the content of 226 ra in normal subhorizontally layered porous travertine decreases with depth in y 10 the observed 226 ra vs depth relation is consistent with continuous deposition of travertine at the y 10 site from 7700 a bp to near present at a mean rate of 1 0 cm a and indicates minimal exchange of ra between travertine and pore water after the early diagenetic transformation of aragonite to calcite these data imply that under favorable conditions 226 ra measurements may be useful in determining ages and deposition rates for other travertines

geomorphological paleontological and 87sr 86sr isotope analyses of early pleistocene paleoshorelines to define the uplift of central apennines italy abstract the eastern border of the middle valley of the tiber river is characterized by several plio pleistocene paleoshorelines which extend for about 100 km along the western margin of the central apennines italy we studied these paleoshorelines by the means of geological and paleontological analyses and new 87 sr 86 sr isotope analyses the youngest and uppermost paleoshorelines have been detected and mapped through detailed geologic and stratigraphic surveys which led to the recognition of nearshore deposits cliff breccias alignments of lithophaga borings fossil abrasion notches and wave cut platforms the altitude of these paleoshorelines decreases almost regularly in the nnw sse direction from 480 to 220 m a s l measurements of the 87 sr 86 sr isotope ratio have been conducted on corals and mollusks collected from sediments outcropping close to the paleoshorelines the isotopic dating results indicate numerical values that range between 0 70907 and 0 70910 all over the 100 km outcrop these results together with biostratigraphic data constrain the age of the youngest paleoshorelines to 1 65 1 50 ma these paleoshorelines are thus considered almost isochronous giving an estimated uplift rate of 0 34 0 17 0 03 mm a moving from nnw to sse shape length and continuity of the 100 km long observed movements indicate that the studied paleoshorelines are an important marker of the quaternary uplift of the central apennines

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

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

warm period growth of travertine during the last interglaciation in southern germany abstract late quaternary travertine at two sites near stuttgart formed entirely during interglacial periods the travertine contains structures from growth induced by bacteria and such structures have been dated by 230th u mass spectrometry the resulting ages from both sites imply growth episodes of short duration with growth rates up to 5 mm yr 1 at 99 800 1300 yr b p 2 n 8 and 105 900 1300 yr b p 2 n 7 these episodes were likely part of marine isotope stage mis 5 3 deposition of silt interrupted travertine growth at one of the sites 105 000 yr b p likely correlatives of this silt are the st germain i b stade recorded in the grand pile peat bog and a cold episode 1000 yr long recorded by 18o values in the grip ice core travertine also formed during stage 5 5 115 000 yr and during the early holocene we found no evidence for travertine accumulation in stages 2 3 4 and 5 1 at both sites the sr u ratio and the initial 234u 238u activity ratio resemble those of modern spring water however the sites differ in the chemical composition of spring water and in stratigraphic sequence of travertine accumulation

tufas and travertines of the mediterranean region a testing ground for freshwater carbonate concepts and developments actively forming travertine and tufa sites are widespread in temperate and warm climates such as the mediterranean region but also develop in other climatic regimes from the arctic to equatorial latitudes the terms travertine and tufa are sometimes applied indiscriminately today however each has a specific definition most studied deposits are active or of quaternary especially holocene age there are fewer tertiary and even less late mesozoic examples on record in part this is because of a recognition problem as these deposits commonly preserve as fragmentary erosional remnants physico chemical precipitation of calcium carbonate is commonly considered to be the main mechanism contributing to tufa and travertine deposition rapid cooling of waters further aids the process in thermal travertine sites however biomediation of calcium carbonate associated with prokaryote microphyte biofilms is now recognized to be equally important in slow flowing and near static sites much of this precipitation occurs in close association with cyanobacterial heterotrophic bacterial and diatoms the mediterranean region figures significantly in the development of travertine and tufa research consequently this article employs key literature on mediterranean examples to illustrate developments and concepts in freshwater carbonate research modern work started in the 1950s and defined many previously unknown outcrops many such sites became the targets for early radiocarbon dating studies since the late 1970s a number of laboratory based and field based classification schemes have been proposed some schemes were based on associated macrovegetation types others were based on petrological characteristics or on geometry and sedimentary facies characteristics of late the sedimentological modelling has benefited greatly from the use of shallow geophysical techniques in order to better define the internal geometries of the deposits two distinct research strands were developed during the 1990s both aimed at a better understanding of environmental change the first considered biocomponents the research was multifaceted and ranged from exploring the role of micro organisms in cement and lime mud precipitation to biostratigraphic analysis of contained pollen and invertebrate remains these provided proxy environmental information which has helped to define past climate variability in the region the second research strand focussed on geochemical signatures as a proxy tool for defining environmental change this definition was made possible by new petrological studies which have greatly aided the recognition of primary depositional fabrics this improved knowledge has reduced the sampling dangers of diagenetic contamination inherent in earlier geochemical studies lithofacies modelling has also brought to light important early post depositional neomorphic changes which obscure primary fabrics and complex diagenetic histories have been revealed stable isotope signatures of carbon and oxygen have also been used to define palaeo water temperature fine tuning of depositional time frames has also been achieved from absolute dating techniques employing radiocarbon and uranium thorium

interaction between shallow and deep aquifers in the tivoli plain central italy enhanced by groundwater extraction a multi isotope approach and geochemical modeling abstract in the tivoli plain rome central italy the interaction between shallow and deep groundwater flow systems enhanced by groundwater extraction has been investigated using isotopic and chemical tracers a conceptual model of the groundwater flowpaths has been developed and verified by geochemical modeling a combined hydrogeochemical and isotopic investigation using ion relationships such as dic cl ca ca mg so 4 so 4 hco 3 and environmental isotopes 18 o 2 h 87 sr 86 sr 34 s and 13 c was carried out in order to determine the sources of recharge of the aquifer the origin of solutes and the mixing processes in groundwater of tivoli plain multivariate statistical methods such as principal component analysis and cluster analyses have confirmed the existence of different geochemical facies and the role of mixing in the chemical composition of the groundwater results indicate that the hydrochemistry of groundwater is characterized by mixing between end members coming directly from carbonate recharge areas and to groundwater circulating in a deeply buried meso cenozoic carbonate sequence the travertine aquifer is fed by both flow systems but a local contribution by direct input in the plain has also been recognized the stable isotope data 18 o 2 h 13 c and 34 s supports the flow system conceptual model inferred from the geochemical data and represents key data to quantify the geochemical mixing in the different groundwaters of the plain the results of numerical modeling phreeqc are consistent with the flowpaths derived from the hydrogeochemical conceptual model the inverse models performed generated the main geochemical processes occurring in the groundwater flow system which also included mixing geochemical and isotope modeling demonstrate an increasing influence of groundwater from the deeply buried aquifer in the travertine aquifer enhanced by lowering of the travertine aquifer water table due to quarry pumping

coordinated incoherent scatter radar observations of the semidiurnal tide in the lower thermosphere the incoherent scatter radars at arecibo 18 3 degree n millstone hill 42 6 degree n and sondrestrom 67 degree n simultaneously observed the thermal structure and dynamics of the earth s lower thermosphere during the period september 21 25 1987 as part of the lower thermosphere coupling study plasma spectral measurements were used to derive ion temperatures and horizontal neutral wind velocities in the altitude region 90 140 km and semidiurnal harmonics were determined from the data sets the daily mean temperatures were found to be within 40 degree k at the three stations and the largest semidiurnal temperature amplitudes exceeding 70 degree k above 115 km were recorded at arecibo mean winds were about plus minus 30 m s at most altitudes shifting from eastward to westward directions at 115 km and the semidiurnal amplitudes were in the range 20 70 m s phase variations with height reveal reasonable consistency among the three stations within 3 4 hours and indicate an average vertical wavelength of 40 70 km however a strong variation is seen in the vertical structure in the 110 to 130 km region suggesting the presence of different tidal modes comparison with the most current tidal propagation model by forbes and vial this issue indicates that the model tends to underestimate the amplitudes for this time period particularlymore above 110 km by virtue of the latitudinal distribution of the three radars their coordinated observations of the lower thermosphere serve to constrain numerical models and improve their understanding of this important yet complex region of the atmosphere less

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

fracture networks and strike slip deformation along reactivated normal faults in quaternary travertine deposits denizli basin western turkey abstract the denizli basin in the west anatolian extensional province in western turkey is known for its numerous quaternary travertine occurrences travertine morphology is often dependant on the relative position of the deposition with respect to basin bounding faults the travertine occurrences examined in this study are situated at the intersection of the locally e w oriented denizli basin and the adjacent ne sw oriented baklan graben in the ne based on an extensive field campaign including lidar scanning several high resolution fault fracture maps of five large quarries 300 m in length and 60 m in height are constructed in which this world class travertine deposit is currently excavated a structural analysis is performed in order to determine the tectonic overprinting of the travertine body and to derive the stress states of the basin after travertine deposition the mostly open non stratabound joints are several tens of metres long and often bifurcate creating a dense fracture network minor infill of the joints resulted in the presence of a few colour banded calcite veins based on the e w ne sw and nw se orientation of three dominant joint sets it is concluded that the joint network is caused by local n s extension alternated by nw se and ne sw extension exemplifying the presence of stress permutations in the quaternary high angle e w to wnw ese faults cross cut the quarries faults are filled with travertine debris and clastic infill of above lying sedimentary units indicative of the open nature of the faults the specific e w fault orientation in the locally e w trending denizli basin indicates that they initiated as normal faults a paleostress inversion analysis performed on kinematic indicators such as striations on the clayey fault infill and the sinistral displacement of paleosols shows that some of the normal faults were reactivated causing left lateral deformation in a transient strike slip stress field with a ne sw oriented 1

classification and environmental models of cool freshwater tufas abstract tufa deposits are common in the quaternary record facies developments are dependent upon localised carbonate precipitation generally these take the form of phytoherm build ups together with associated detrital deposits derived from disagragation of the former phytoherm cements differ from speleothems and floe calcite accumulations in being biologically mediated or modified this paper recognises the following five types perched spring line cascade fluviatile paludal and lacustrine facies each type is composed of distinctive constructional and detrital sediment associations these unique sediment combinations are the product of an interplay between angle of slope water discharge rate standing water bodies phytal and microbial colonization and ambient temperature the proposed models will be of value in the interpretation of ancient and partially exposed tufas

uranium series dating of travertine from suttő implications for reconstruction of environmental change in hungary abstract terrestrial carbonate formations such as travertines speleothems and lake sediments are important archives of terrestrial climate forcing at the sutt section in hungary a complex succession of travertine is covered by a loess palaeosol sequence both are high resolution terrestrial archives of climate and environment change uranium series 230th u dating was carried out to set up a more reliable chronological frame for the travertine as the growth of travertine is very complex pore cements may cause serious problems for precise dating the state of alteration of primary spar and micrite was characterised by microscopic cathodoluminescence and microprobe analyses the travertine from sutt showed homogeneous phases of primary calcite minor micropores and rare pore cements the carbon isotopic composition indicates that the source of carbon was a mixture of atmospheric and soil derived co2 calculated water temperatures based on oxygen isotope data range from 22 c to 31 c an attempt to provide an independent relative dating approach by palaeomagnetic techniques failed 230th u ages were determined applying an isochron approach using the leachate leachate method as the travertine deposits have a dense structure the bulk sampling method was successfully applied in determining uranium series ages with much higher precision than former studies with alpha spectrometry travertines from sutt yielded mid pleistocene ages ranging from the antepenultimate glacial to the penultimate interglacial 310 240 ka these results are in agreement with those from optically stimulated luminescence osl dating and amino acid racemisation aar dating of the overlying sediment indicating at least an mis 7 age for the travertine

chemical and stable isotope composition of recent hot water travertines and associated thermal waters from egerszalok hungary depositional facies and non equilibrium fractionation abstract combined petrographical mineralogical geochemical and stable isotope analyses were conducted on an actively forming egerszalok travertine mound to determine the factors that govern carbonate precipitation and thus influence the use of travertines in paleoclimate reconstruction stable isotope analyses of oxygen carbon and hydrogen demonstrate both biological and abiological factors to control travertine deposition processes of morphology related outgassing had major effects upon isotopic composition continuous co 2 degassing and temperature change of the thermal water between the spring orifice and distal parts of the system caused stable carbon and oxygen isotope compositions of the precipitating travertines to increase from 2 7 to 4 3 relative to v pdb and from 10 5 to 14 7 relative to v smow respectively the travertines at the spring orifice t 67 c are composed of almost pure calcite with a 13 c value of 2 7 relative to v pdb enabling classification as intermediate between thermometeogene and thermogene in lower temperature water away from the spring orifice various amounts of aragonite 5 35 with higher sr concentrations precipitate from solution this phenomenon is exceptional in hot spring carbonate deposits and could be explained by fast carbonate precipitation due to the morphology related outgassing oxygen and hydrogen isotope measurements of the thermal water confirmed evaporation to be causing limited kinetic isotope fractionation however 18 o values of the travertine do show isotope shifts away from the equilibrium fractionation curve which is most probably related to the rapid calcite precipitation and transportation along the flow path our data closely follow the temperature 18 o calcite water relationship observed for other travertine localities this is slightly displaced from the experimental curve and determines an empirical travertine curve our study shows that this shift may result in an approximately 8 c difference in paleotemperature calculations depending upon which fractionation curve is used

geochronology of the most recent activity in the sabatini volcanic district roman province central italy abstract the presence of young highly explosive volcanoes in the densely populated roman area central italy makes the evaluation of the long term volcanic hazard a crucial point the sabatini volcanic district svd part of the potassic quaternary roman province extends over an area of 1800 km2 including the city of rome here we report twenty six new 40ar 39ar age analyses of pyroclastic and lava units in order to put time constraints on the most recent svd eruptive activity i e post dating 400 ka as a groundwork for a detailed reconstruction of the whole volcano tectonic evolution integrated geochronological and field evidence shows that svd volcanism maintained a typical areal character through the whole history both effusive and explosive activity phases from different source areas and volcano tectonic settings overlapped in time and space while climactic phases migrated repeatedly through time in particular new geochronological data better constrain a climactic phase of activity at around 300 ka related to the bracciano volcano tectonic depression and the sacrofano caldera and point out that the most recent eruptive activity in the svd took place from time space clustered hydromagmatic centres at least up to 90 ka in addition we remark some parallelism among major activity phases in the svd and the nearby districts of the roman province with possible implications on quaternary regional tectonics finally new age data put constraints on tephrostratigraphic correlations through the apennine chain and the adriatic sea

sedimentological and geochemical characteristics of a fluvial travertine a case from the eastern mediterranean region a sedimentological and geochemical study was performed on the travertines in the southern part of the usak geothermal field western turkey to assess the applicability of a fluvial tufa facies model in interpreting late quaternary travertine deposits developed along the stream valleys that follow fault and fracture systems modern thermal 31 to 38 c springs are found on the floor of the valley between 480 m and 520 m above sea level the distribution and nature of travertine facies were determined from natural outcrops samples of the travertines and spring water were characterized using a range of geochemical and petrographic methods waterfall slope and pool facies associations consist of various combinations of travertine facies and subordinate detrital facies waterfall and slope facies associations of the older deposits occur where the springs emerged onto a hillslope or topographic break in contrast the pool facies association developed in depressions or flat areas that were fed by thermal springs the youngest generation 1 85 ka precipitated at lower elevations than the older ones 147 to 153 ka stable carbon and oxygen isotope values of the aksaz travertines range between 4 3 and 6 3 vienna pee dee belemnite and 12 6 and 7 2 vienna pee dee belemnite respectively the high d 13 c values suggest that the thermal waters were charged with isotopically heavy co2 of deep origin based on palaeotemperature calculations the temperatures of the palaeosprings are slightly higher up to 44 c than the present equivalents but sometimes the temperature is lower probably due to mixing with the stream water although the thermal waters occasionally are impeded by fluvial activity travertine precipitation occurs in the protected parts of the aksaz stream valley this contribution highlights the applicability of the fluvial facies model for tufa for the interpretation of travertine deposits worldwide

the history of the monti sabatini and alban hills volcanoes groundwork for assessing volcanic tectonic hazards for rome abstract the volcanic rocks of rome provide chronostratigraphic constraint that is of use to geologists archaeologists and paleontologists identifying the areal distribution of these rocks their mode of emplacement and a detailed chronology of the eruptive events also is crucial for assessing local natural hazards in a volcanic tectonic context and for recognizing whether the volcanoes may erupt again in the future we have identified and dated many of the volumetrically significant eruptive units from the monti sabatini and alban hills colli albani and propose a formalized volcanic stratigraphy for rome it is probable that seismic events triggered some eruptions as several ignimbrites from the two volcanoes have statistically indistinguishable ages following a 200 kyr period of dormancy that was coincident with a pulse of regional uplift the alban hills appears to have begun recently circa 45 ka a new eruptive cycle therefore accurate assessment of volcanic tectonic hazards and estimation of possible future volcanic activity is necessary for the safety of the five million people living near these volcanoes

studying travertines for neotectonics investigations middle late pleistocene syn tectonic travertine deposition at serre di rapolano northern apennines italy middle late pleistocene tectonic activity has been inferred through studies on travertine deposits exposed in a tract of the hinterland northern apennines a detailed study on the relationships between tectonics and travertine deposition coupled with 230th 234u age determination of travertines at cava oliviera quarry located close to serre di rapolano village southern tuscany northern apennines allowed us to recognise pleistocene faults whose activity has been referred to 157 24 ka at least travertine deposition was tectonically controlled by wsw ene striking oblique and normal faults associated to a main fault named as the violante fault this structure dissected a regional normal fault known as the rapolano fault early middle pliocene in age which bounded the eastern side of the pliocene siena basin and gave rise to space accommodation for clayey and sandy marine sediments hydrothermal circulation and related travertine deposition was favoured by the damaging enhancement due to the fault fault intersection tectonic activity has been also documented by deformation recorded by travertines which suggest a main tectonic event between 64 5 and 40 5 ka the tectonic activity described for the study area agrees with the quaternary tectonic evolution documented in the surrounding areas e g mt amiata and mt vulsini as well as the tyrrhenian margin of the central apennines indicating that a widespread tectonic activity affected the inner part of the apennines until the latest quaternary

the quaternary travertine deposits of europe and asia minor abstract a summary is provided of the published information relating to all aspects of quaternary travertine formation in europe west of the ural mountains the deposits have been divided into two broad groups the meteogene travertines which result primarily from the degassing of soil borne aqueous co 2 and thermogene deposits resulting from the degassing of thermally generated co 2 meteogene deposits are rare above latitude 58 n and in regions where the mean annual air temperature is below 5 c a significant positive correlation exists between mean air temperature and travertine deposit thickness the combined effects of temperature and rainfall are used to provide a zoned map showing the travertine forming potential of limestones within the region information from 14 c dating indicates that deposition reached a maximum in the period 5 10 ka bp and is currently limited by land and water management practices in the populated areas thermogene deposits occur in regions of high co 2 discharge resulting from tectonic activity such as italy and turkey where there is much vulcanism these travertines are frequently more massive and less readily weathered than meteogene deposits fully referenced information is provided for 320 important mostly well studied sites 227 meteogene 93 thermogene of which 156 are currently active

the subsurface geology of rome sedimentary processes sea level changes and astronomical forcing abstract in this paper we present a reconstruction of the stratigraphic setting of the continental sedimentary sequences that were deposited by the paleo tiber river within the greater area of rome between 0 9 and 0 6 ma carried out through analyses of a large number of borehole data through palinspastic restoration of several cross sections we depict the original geometry of the sedimentary record that has been dislocated by intense tectonic activity linked to volcanism and we reconstruct the geologic and paleogeographic evolution of this area moreover we provide a complete review of the chronostratigraphic and magnetostratigraphic data reported in previous work and we extend paleomagnetic analyses to three new clay sections these geochronological constraints allow us to compare aggradation of the paleo tiber sedimentary successions with the 18o record evidencing a strict link between sedimentation and sea level changes in the rome area by doing so we provide a direct test on the timing of the sea level rise for mis 19 through mis 15 a record of data for which no equivalent exists in the literature

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

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

development of the cambazli turgutlu manisa fissure ridge type travertine and relationship with active tectonics gediz graben turkey abstract travertine occurrences in the cambazli village area exist at the western edge of the gediz graben comprising the turgutlu neogene basin the cambazli travertine was classified into two main groups based on physical mineralogical and petrographic properties occurrences of travertine are probably due to faulting between the paleozoic units of menderes massif and the pliocene kanlitepe formation group i travertine is horizontal and oriented ne sw and nw se whereas group ii travertine occurrences are oriented e w direction the cambazli travertine is a fissure ridge type travertine continues to develop both in fissures and on the topographic surface as bedded deposits layered travertine is deposited on both surfaces of fissures it develops either symmetrically or asymmetrically with respect to the centre of the fissure kinematical analyses of listric normal fault measurements demonstrate that nne ssw extension occurred the cambazli travertine in the gediz graben has been deposited by hydrothermal waters rising through fracture systems probably related to an active listric normal fault developed in the north of the study area

strike slip deformation and u th dating of travertine deposition examples from north anatolian fault zone bolu and yenicag basins turkey the relation of the travertine deposition outcropping in the bolu and yenicaga basins located to the west of the north anatolian fault system nafs with the faulting of the zone nafz of the system in this part is examined these travertines are dated by u series travertine formations in the bolu and yenicaga basins are deposited in different ways and localities on pressure ridges in the releasing restraining bends of the strike slip faults and around the intersection of faults while the travertines of the uctepeler and belemur hill are deposited on the pressure ridges the travertines deposited in cigdem hill and cepni are deposited in the releasing restraining bends of the faults of the zone and the travertines in golkoy are deposited on the foot wall of the intersecting of the normal faults which encircles the west side of the basin as a result of the dating of the travertines on the study area by u series method the age data range between 52 649 8040 a and 96 308 17 674 a and between 17 962 1671 a and 133 463 76 882 a in the yenicaga and basins respectively information on fault activity is gained as a result of the dating of the travertines deposited due to the strike slip deformation on different segments of the nafz