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

u th dating of freshwater travertine from middle velino valley central italy paleoclimatic and geological implications abstract six travertine bodies outcropping along the middle velino valley central italy have been studied and dated using the u th method in order to obtain new chronological constraints for the recent geological evolution of the area the lithological and sedimentological characteristics of travertines have been described showing that such deposits can be referred to waterfall pool terraces and gentle slopes environment travertines have formed during warm periods and can be referred to marine oxygen isotope stages 5 3 and 1 travertine deposition seems to stop around 5 ka bp according to other european and italian sites pollen stratigraphy and ostracod assemblages from the close sequence of valle di castiglione characterized by the same climatic conditions of velino valley have confirmed that periods of velino valley travertine deposition were effectively characterized by warm and wet climatic conditions seismic activity strongly active in the area since the middle pleistocene has deeply influenced the location and the discharge of springs which have deposited the travertines influencing in turn the shape and size of travertine bodies

differences in the 14c age δ13c and δ18o of holocene tufa and speleothem in the dinaric karst we studied holocene speleothems and tufa samples collected in numerous caves and rivers in the dinaric karst of croatia slovenia bosnia and herzegovina as well as serbia and montenegro differences in the formation process of tufa and speleothems are discussed in the context of their isotopic composition 14 c 13 c and 18 o as well as the chemistry of surface water rivers lakes and drip water in caves the physical and chemical parameters monitored in the surface water tufa precipitation and drip water speleothem precipitation show that more stable conditions accompany speleothem rather than tufa formation this is particularly obvious in the water temperature variations 2 22 c in surface water and 7 12 c in drip water and in saturation index variation 3 11 in surface water and 1 6 in drip water the range of 14 c ages recorded by holocene speleothems v12 000 yr is wider by several thousands years than that of holocene tufa samples v6000 yr n 13 c values for tufa samples range from 312x to 36x and for speleothem samples from 312x to 3x reflecting higher soil carbon and or vegetation impact on the process of tufa than on speleothem formation the differences in n 18 o values of tufa and speleothem samples from different areas reflect different temperature conditions and differing isotopic composition in the water the study shows that speleothems from the dinaric karst can be used as global palaeoclimatic records whereas tufa records changes in the local palaeoenvironment 2003 elsevier science b v all rights reserved

improved fourier terrain correction part ii fourier methods for potential fields have always been developed with the simplification that the calculation surface is a level plane the fourier approach can be extended to deal with an uneven observation surface i consider the case of terrain correction for gravity surveys in which the attraction of a variable thickness layer is calculated at points on its upper surface the main idea is to use a power series in topographic height that is then converted into a series of convolutions to avoid convergence problems a cylindrical zone around the observer must be removed from the fourier treatment and its contribution computed directly the resultant algorithm is very fast in an example based on a recent survey the new method is shown to be more than 300 times faster than a calculation based on summing contributions from a column of material under each topographic grid point

hot spring systems geobiology abiotic and biotic influences on travertine formation at mammoth hot springs yellowstone national park usa multiple abiotic and biotic factors combine in nature to influence the formation of calcium carbonate limestone deposits systems geobiology studies of how micro organisms respond to or sometimes even control the coupled effects of environmental change and mineralization will permit more accurate interpretation of the fossil record of ancient microbial life mammoth hot springs in yellowstone national park usa serves as a natural laboratory for tracking how the dynamic interplay of physical chemical and biological factors come together to form hot spring limestone called travertine systematic downstream correlations occur at mammoth hot springs between travertine deposition geomorphology crystalline structure and geochemistry microbial communities mat morphology pigmentation and phylogenetic and metabolic diversity and spring water conditions temperature ph geochemistry and flow field based microscale and mesoscale experimentation indicates that microbes directly influence travertine growth rate and crystalline structure at the macroscale time lapse field photography and numerical modelling suggest that travertine terrace geomorphology is influenced strongly by hydrology heat dispersion and geochemistry these results from mammoth hot springs allow establishment of a conceptual framework across broad spatial and temporal scales in which to track how multiple geological and biological factors combine to control caco3 crystal precipitation and the resulting formation of travertine deposits

depositional facies and aqueous solid geochemistry of travertine depositing hot springs angel terrace mammoth hot springs yellowstone national park u s a petrographic and geochemical analyses of travertine de positing hot springs at angel terrace mammoth hot springs yellow stone national park have been used to define five depositional facies along the spring drainage system spring waters are expelled in the vent facies at 71 to 73 8c and precipitate mounded travertine composed of aragonite needle botryoids the apron and channel facies 43 728c is floored by hollow tubes composed of aragonite needle botryoids that encrust sulfide oxidizing aquificales bacteria the travertine of the pond facies 30 62 8c varies in composition from aragonite needle shrubs formed at higher temperatures to ridged networks of calcite and aragonite at lower temperatures calcite ice sheets calcified bubbles and aggregates of aragonite needles fuzzy dumbbells pre cipitate at the air water interface and settle to pond floors the prox imal slope facies 28 54 8c which forms the margins of terracette pools is composed of arcuate aragonite needle shrubs that create small microterracettes on the steep slope face finally the distal slope facies 28 30 8c is composed of calcite spherules and calcite feather crys tals despite the presence of abundant microbial mat communities and their observed role in providing substrates for mineralization the com positions of spring water and travertine predominantly reflect abiotic physical and chemical processes vigorous co 2 degassing causes a 12 unit increase in spring water ph as well as rayleigh type covariations between the concentration of dissolved inorganic carbon and corre sponding d 13 c travertine d 13 c and d 18 o are nearly equivalent to aragonite and calcite equilibrium values calculated from spring water in the higher temperature 50 738c depositional facies conversely

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

relationship between tectonics volcanism sedimentation and basin development late cenozoic central part of northern honshu japan abstract a pronounced interplay between tectonics volcanism and sedimentation can be established in the volcanic arc region of the central part of northern honshu during the early miocene to quaternary interval four stages are recognized with the type of volcanism and sedimentation varying according to the tectonic stress regime 1 1 rifting stage 22 15 ma ns trending half grabens were formed under an extensional stress regime related to the rifting of the sea of japan basins were rapidly filled by intermediate to felsic volcanic products which are often associated with subaerial fluvial and lacustrine sediments 2 2 back arc basin opening stage 15 13 ma with more advanced stagess of rifting subsidence from crustal stretching resulted in marked marine incursion and an overall transgressive succession developed during this stage the back arc side of northern honshu subsided rapidly to middle bathyal environments at the same time associated with the opening of the sea of japan large volumes of regionally extensive mafic lavas and associated hyaloclastites were erupted within submarine grabens in contrast in the present backbone ranges felsic volcanism occurred within bathyal to shallow marine environments igneous rock types in this stage display a bimodal mafic felsic chemistry 3 3 transitional stage 13 2 4 ma a thermal subsidence substage 13 8 ma an intermediate stress regime developed which included phases of both weak extension and compression consequently grabens along the sea of japan ceased to form later lithospheric cooling eventually led to thermal subsidence of the back arc region and hemipelagic sediments mantled the previously active mafic volcanic apron volcanism at this time was mainly restricted to a narrow zone along the present backbone ranges where felsic to intermediate volcanic products accumulated within shallow marine environments b incipient compressional substage 8 2 4 ma hemipelagic sedimentation continued on the back arc side of northern honshu along the present backbone ranges the intermediate stress regime continued with formation of many large caldera structures associated with subaerial felsic volcanism 4 4 shortening deformation stage 2 4 ma present the change of the absolute direction of motion of the pacific plate at the early to middle pliocene changed the regional stress regime of the volcanic arc from intermediate to compression movement of back arc thrusts along the sea of japan coast began 2 3 ma and led to uplift of the volcanic arc continued compression in the volcanic arc produced narrow uplifted zones with associated basins bounded by reverse faults these basins were filled rapidly by terrestrial sediments containing upward coarsening sequences under this highly compressional tectonic stress regime volcanism became intermediate mafic in composition with large stratovolcanoes becoming prominent

origin of annual laminations in tufa deposits southwest japan abstract laminated tufas and a tufa depositing stream in sw japan shirokawa ehime prefecture were studied monthly over a 3 yr period a series of samples from the tufa clearly reveals the pattern of annual laminations the annual layering pattern was primarily controlled by changes in the rate of calcite precipitation as calculated from water chemistry the concentration of dissolved caco 3 which correlates with the precipitation rate was high in summer autumn and low in winter spring owing to changes in the partial pressure of co 2 in underground air regular seasonal changes in underground pco 2 probably resulted from two temperature dependent processes the diffusion of soil co 2 and the ventilation of underground air these changes in addition to water temperature changes altered the precipitation rate which has a clear seasonal pattern especially in the lower stream the seasonal precipitation rate was high in summer autumn and low in winter spring which is consistent with the seasonal lamination pattern seen in the tufas the textures of collected samples show that the laminations consist of densely calcified summer autumn june october laminae and lightly calcified winter spring november may laminae we infer that the increased precipitation rate stimulated thick calcite encrustation on cyanobacterial filaments to produce the dense textures this interpretation is supported by the lowered organic inorganic carbon production ratio in summer autumn seasonal variations in cyanobacterial assemblages are present but do not reflect the seasonal lamination pattern because the relevant processes are temperature dependent the seasonal lamination pattern at shirokawa is thought to generally apply to other laminated tufas deposited in temperate climates however a reversed pattern can result from local and climatic circumstances dense laminae were deposited in winter near the source of the spring at shirokawa because calcite precipitation was high owing to low underground pco 2 in winter reversed patterns reported from northwestern europe were probably influenced by seasonal rainfall which is reflected in hydrological conditions

holocene environmental changes in lake bangong basin western tibet part 1 chronology and stable isotopes of carbonates of a holocene lacustrine core abstract a 12 4 m core collected from the eastern part of lake bangong is analyzed for mineralogy radiometric chronology and stable isotope contents of authigenic inorganic carbonate isotopic compositions of the modern lake waters and of its major tributaries are first presented radiocarbon activity of these waters show that equilibrium with the atmospheric co2 is not reached because of admixture of dead carbon in solution in the system a model is thus developed to correct the radiocarbon ages of fossil material of aquatic origin for this ageing the core provides a continuous holocene record changes in mineralogy of bulk sediments and in 13c and 18o contents of authigenic carbonates reveal extremely large changes in environmental conditions induced by climate changes and or local hydrological factors e g closure opening of the lake system controlled by the altitude of the outflow sill the eastern basin of lake bangong was closed before 9 6 and after 1 2 ka b p in response to aridity on the catchment wet warm conditions attributed to the monsoon influence were established suddenly at 9 6 ka b p and maintained until 6 2 ka b p although minor reversal events occurred between 8 6 and 7 7 ka b p the return towards aridity is non linear dry spells at 6 2 3 9 3 2 and 1 3 ka b p are alternated with short term periods with positive precipitation evaporation balance

mars global digital dune database mgd 3 global dune distribution and wind pattern observations abstract the mars global digital dune database mgd 3 is complete and now extends from 90 n to 90 s latitude the recently released south pole sp portion mc 30 of mgd 3 adds 60 000 km 2 of medium to large size dark dune fields and 15 000 km 2 of sand deposits and smaller dune fields to the previously released equatorial eq 70 000 km 2 and north pole np 845 000 km 2 portions of the database bringing the global total to 975 000 km 2 nearly all np dunes are part of large sand seas while the majority of eq and sp dune fields are individual dune fields located in craters despite the differences between mars and earth their dune and dune field morphologies are strikingly similar bullseye dune fields named for their concentric ring pattern are the exception possibly owing their distinctive appearance to winds that are unique to the crater environment ground based wind directions are derived from slipface sf orientation and dune centroid azimuth dca a measure of the relative location of a dune field inside a crater sf and dca often preserve evidence of different wind directions suggesting the importance of local topographically influenced winds in general however ground based wind directions are broadly consistent with expected global patterns such as polar easterlies intriguingly between 40 s and 80 s latitude both sf and dca preserve their strongest though different dominant wind direction with transport toward the west and east for sf derived winds and toward the north and west for dca derived winds

factors controlling present day tufa dynamics in the monasterio de piedra natural park iberian range spain depositional environmental settings sedimentation rates and hydrochemistry the tufa record and hydrochemical characteristics of the river piedra in the monasterio de piedra natural park ne spain were studied for 6 years the mean discharge of this river was 1 22 m3 s the water was supersaturated with calcium carbonate the hco3 ca2 and tdic concentrations decreased along the 0 5 km long studied stretch whereas the calcite si showed no systematic downstream or seasonal variation over the same stretch several sedimentary subenvironments exist in which four broad types of tufa facies form 1 dense laminated tufa stromatolites 2 dense to porous massive tufa 3 porous coarsely laminated tufa with bryophytes and algae and 4 dense hard laminated deposits in caves the half yearly period thickness and weight of sediment accumulated on 14 tablets installed in several subenvironments showed that the deposition rate was greater in fast flowing river areas and in stepped waterfalls and lower in slow flowing or standing river areas and in spray and splash areas mechanical co2 outgassing is the main factor controlling calcite precipitation on the river bed and in waterfalls but this process does not explain the seasonal changes in depositional rates the deposition rates showed a half yearly period pattern recorded in all fluvial subenvironments persistent over time 5 26 mm 0 86 g cm2 in warm periods 2 26 mm 0 13 g cm2 in cool periods mass balance calculations showed higher calcite mass values in warm 21 58 mg l than in cool 13 68 mg l periods this biannual variation is mainly attributed to the seasonal differences in temperature that caused changes in inorganic calcite precipitation rate and in biomass and the correlative photosynthetic activity tufa sedimentation was therefore controlled by both physicochemical and biological processes the results of this study may help test depositional rates and their environmental controls and thus assess the climatic and hydrological significance of ancient tufas in semi arid conditions in particular in the quaternary

preferential soft tissue preservation in the hot creek carbonate spring deposit british columbia canada abstract the relict holocene hot creek carbonate spring deposit in southeast british columbia is characterized by excellent preservation of soft tissue organisms e g cyanobacteria but poor preservation of organisms with hard tissue e g wood diatoms the deposit is formed mainly of calcified cyanobacteria with fewer mineralized macrophytes plants bryophytes mosses wood and diatoms cyanobacteria grew as solitary filaments lyngbya and as radiating hemispherical colonies rivularia both were preserved by encrustation and encapsulation while alive and as casts after filament death and decay sheath impregnation was rare to absent filament encrustation whereby calcite crystals nucleated on and grew away from the sheath exterior produced moulds that replicated external filament morphology but hastened filament decay filament encapsulation whereby calcite nucleated in the vicinity of and grew towards the encapsulated filament promoted sheath preservation even after trichome decay subsequent calcite precipitation inside the hollow sheath generated sheath casts the inability of mineralizing spring water to penetrate durable cell walls meant that bryophytes macrophytes and most wood was preserved by encrustation some wood resisted complete decay for several thousand years and its lignified cell walls allowed rare permineralizations diatoms were not preserved in the relict deposit because the frustules were dissolved by the basic spring water amorphous calcium carbonate produced by photosynthetic co 2 removal may have acted as nucleation sites for physicochemically precipitated calcite thus metabolic activities of floral organisms probably initiated biotic mineralization but continuous inorganic calcite precipitation on and in flora ensured that soft tissues were preserved

wet dry seasonal variations of hydrochemistry and carbonate precipitation rates in a travertine depositing canal at baishuitai yunnan sw china implications for the formation of biannual laminae in travertine and for climatic reconstruction travertine or tufa is a chemical sedimentary deposit that is precipitated from springfed stream water supersaturated with calcite due to co2 degassing liu et al 1995 pentecost 1995 ford and pedley 1996 these deposits have biannual laminations which could provide valuable paleoclimatic and paleoenvironmental information with high resolution liu et al 2006 kano et al 2007 brasier et al 2009 lojen et al 2009

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

travitonics using travertines in active fault studies abstract late quaternary travertines deposited from hot springs can reveal much about the neotectonic attributes and histories of structures on the basis of field studies in the aegean region turkey and greece the northern apennines italy and the basin and range province usa we conclude that the following relationships are of predictive value i travertine deposits are preferentially located along fracture traces either immediately above extensional fissures or in the hanging walls of normal faults ii the locations of many travertine fissure ridge deposits coincide with step over zones relay ramps between fault segments networks of intersecting tensional fissures reflecting the complex strains experienced in such settings are probably responsible for enhancing hydrothermal flow iii the morphology of travertine deposits overlying extensional fissures is controlled by the rheology of the underlying materials tufa cones towers pinnacles form on former and present lake floors where fissures underlie unconsolidated sediments whereas fissure ridges develop where fissures cut bedrocks at the surface iv fissure ridges comprise outwardly dipping bedded travertine flanking a central tensional fissure filled by vertically banded travertines fissures can be used to infer local stretching directions v where there are travertines datable by the u series method it is possible to calculate time averaged dilation and lateral propagation rates for individual fissures vi most fissures cutting fissure ridges comprise self similar angular segments with fractal dimensions in the range 1 00 1 12 the properties of bedded travertine combined with stress perturbations at fissure tips probably being responsible for such similar fractal dimensions being inferred from such a wide range of locations fissures gradually increasing in width with depth are products of continuous fracture dilation in contrast to those that form during episodic dilation which display stepped increases of width with depth vii travertine deposited from springs along fault zones accumulate in terraced mounds sited down slope of the spring line viii many post depositional fractures cutting travertine deposits are locally oriented at right angles to deposit margins and ix systematic joints in travertines are restricted to those parts of eroded sheet deposits that have been exhumed

deposition and diagenesis of mammoth hot springs travertine yellowstone national park wyoming u s a strata forming a 113 m long core through mammoth hot springs record the holocene evolution of this travertine accumulation from deposition as part of a lacustrine to a terraced mound environment the deposit is readily divided into four intervals 113 67 m carbonate cemented volcaniclastic with intercalated layers of travertine 67 60 m moderately pure travertine with some volcaniclastics 60 50 m carbonate cemented volcaniclastic rich interval and 50 0 m essentially pure travertine lithologic composition sedimentary structures and the rare ostracode fossils indicate that the lower 67 m predominantly accumulated in a lacustrine environment whereas the upper 40 m are terraced mound deposits all of the travertine is calcite some after aragonite layers of shrubs oncoids and peloids all bacterial in origin form the dominant allochems within the travertine stable isotopic carbon and oxygen values n 128 are strongly positively correlated and decrease up core 4 and 8 respectively reflec

speleothems travertines and paleoclimates abstract age data for about 660 speleothems and about 140 spring deposited travertines were collected including many unpublished results these data were plotted as histograms and also as error weighted frequency curves on a 350 000 yr scale these plots clearly show periods of increased speleothem travertine growth as well as times of cessation the periods of most frequent speleothem growth were between approximately 130 000 and 90 000 yr ago and since about 15 000 yr ago such periods before 150 000 yr ago however cannot be yet recognized because of a lack of sufficient data and the associated uncertainties of dates in this age range a comparison with the oxygen isotope record of deep sea core v28 238 shows a clear relationship indicating that terrestrial calcite formation is controlled by paleoclimatic fluctuations the evident climatic stimulation of quaternary calcite formation is readily explained geochemically and is substantiated by the obvious difference in speleothem travertine growth as a function of geographic position

travertine deposition and faulting the fault related travertine fissure ridge at terme s giovanni rapolano terme italy in this paper we describe an example of travertine fissure ridge development along the trace of a normal fault with metre displacement located in the eastern margin of the neogene quaternary siena basin in the terme s giovanni area rapolano terme italy this morphotectonic feature 250 m long 30 m wide and 10 m high formed from supersaturated hot waters 39 9 c flowing from thermal springs aligned along the trace of the normal fault dissecting travertines not older than late pleistocene 24 3 ka a straight continuous fissure with a maximum width of 20 cm occurs at the top of the ridge along its crest hot fluids flow from cones mainly located at the extremities of the ridge where travertine is depositing the travertine fissure ridge shows an asymmetrical profile since it buries the fault scarp the difference in height of slopes corresponds to the vertical displacement of the normal fault fissuring of the recent travertine deposits along the strike of the crestal fissure as well as recent hydrothermal circulation lead us to believe that the terme s giovanni normal fault may be currently active on the whole the terme s giovanni fissure ridge can be defined as a travertine fault trace fissure ridge adding a helpful example for studying the relationship between faulting and travertine deposition