quantitative reconstruction of mid to late holocene climate in ne china from peat cellulose stable oxygen and carbon isotope records and mechanistic models there has been an increasing need to reconstruct past climate from proxy records quantitatively and mechanistically the inverse proxy modeling method stands out as a novel approach to quantitative palaeoclimate reconstructions through integrating process based models and proxy records representing a major progress in quantitative palaeoclimatology it has been proposed to incorporate multiple proxy records to produce a more robust constraint on the climate parameters sought for estimation and most of the work has been conducted using pollen records in conjunction with vegetation models here i show a worked example of using paired stable oxygen and carbon isotope records of peat cellulose from one single core to infer the climate history in ne china for the last 6000 years through solving a well posed inverse problem using bayesian statistics the quantitative palaeoclimate data obtained in this study may deepen our insight into the dynamics of the east asian summer monsoon mean growing season temper

data resolution matrix and model resolution matrix for rayleigh wave inversion using a damped least squares method inversion of multimode surface wave data is of increasing interest in the near surface geophysics community for a given near surface geophysical problem it is essential to understand how well the data calculated according to a layered earth model might match the observed data a data resolution matrix is a function of the data kernel determined by a geophysical model and a priori information applied to the problem not the data a data resolution matrix of high frequency 2 hz rayleigh wave phase velocities therefore offers a quantitative tool for designing field surveys and predicting the match between calculated and observed data we employed a data resolution matrix to select data that would be well predicted and we find that there are advantages of incorporating higher modes in inversion the resulting discussion using the data resolution matrix provides insight into the process of inverting rayleigh wave phase velocities with higher mode data to estimate s wave velocity structure discussion also suggested that each near surface geophysical target can only be resolved using rayleigh wave phase velocities within specific frequency ranges and higher mode data are normally more accurately predicted than fundamental mode data because of restrictions on the data kernel for the inversion system we used synthetic and real world examples to demonstrate that selected data with the data resolution matrix can provide better inversion results and to explain with the data resolution matrix why incorporating higher mode data in inversion can provide better results we also calculated model resolution matrices in these examples to show the potential of increasing model resolution with selected surface wave data

sedimentology stratigraphy and paleoclimate at the late miocene coffee ranch fossil site in the texas panhandle abstract the late miocene coffee ranch fossil assemblage contains some of the earliest evidence of c4 herbivory in north america however little is known regarding the environmental setting associated with the fauna and a general lack of detailed paleoclimate data exists for the late miocene from the north american continental interior in this study the sedimentary environments stratigraphy geochronology and paleoclimate are interpreted for a series of outcrops of the late miocene ogallala formation in the texas panhandle that includes the coffee ranch locality updated magnetostratigraphy coupled with previously published geochronology indicates that all exposed strata were deposited over a 277 kyr interval within chron c3an 2n from 6 42 6 70 ma depositional environments include fluvial channels floodplain ponds floodplain paleosols eolian paleosols riverine tufa and reworked volcanic ash trunk and tributary fluvial channels are differentiated using channel dimensions sedimentary structures and bounding surface architecture and indicate seasonally variable discharge paleosols from nine pedofacies are described and preserve a spectrum of weakly developed entisols and weakly to moderately mature inceptisols and vertisols constitutive mass balance calculations reveal that mature paleosols formed along distinct pedogenic pathways calcic vertisols accumulated pedogenic carbonate and exhibited either net volumetric dilation or collapse as a result of mineral weathering in contrast non calcic vertisols show patterns of decalcification and variable degrees of volumetric dilation and collapse the presence of the paleosols described in this study requires paleoprecipitation between of 900 1150 mm yr approximately double modern values and a westward shift of the continental udic ustic soil moisture boundary by 400 km during the late miocene this finding suggests that climates in the southern midcontinent were not sufficiently arid to select for c4 photosynthetic pathways over c3 photosynthesis in the late miocene

influence of changing atmospheric circulation on precipitation δ18o temperature relations in canada during the holocene postglacial precipitation 18o history has been reconstructed for two regions of canada long term shifts in the oxygen isotope composition of annual precipitation 18op in southern ontario appear to have occurred with a consistent isotope temperature relation throughout the past 11 50014c yr the modern isotope temperature relation in central canada near present boreal treeline evidently became established between 5000 and 4000 years ago although the relation during the last glacial maximum and deglaciation may also have been similar to present in the early holocene however unusually high 18opapparently persisted in spite of low temperature locally probably associated with high zonal index a rudimentary sensitivity analysis suggests that a small reduction in distillation of moisture in pacific air masses traversing the western cordillera perhaps accompanied by a higher summer winter precipitation ratio could have been responsible for the observed effect equivalent isotope temperature anomalies apparently occurred elsewhere in western north america in response to changing early holocene atmospheric circulation patterns suggesting that a time slice map of 18opfor north america during this period might provide a useful target for testing and validation of atmospheric general circulation model simulations using isotopic water tracers

oxygen isotope record of paleorainwater in authigenic carbonates of chinese loess paleosol sequences and its paleoclimatic significance abstract oxygen isotopic compositions of rhizoconcretions and land snail shells were measured to reconstruct the 18o profiles of paleorainwater 18op for well dated loess paleosols in luochuan china to assess the paleoclimatic significance of 18op factors that control the spatial and temporal 18o variations of rainwater in east asian monsoon regions were investigated modern records indicate that the spatial 18o variations of modern rainwater 18om are closely related to near surface temperature t and the amount of precipitation p in order to separate the effects of t and p on the 18om a linear relationship between 18om t and the natural logarithm of p is established by multiple regressing analyses 18 o m 1 070 0 326 t 2 041 ln p the 18o of paleorainwater over the past 130 ka in luochuan area is calculated by the modern spatial 18o t p relationship using estimated t and p from other paleoclimate records the calculated 18o match well to those reconstructed from the authigenic carbonates which implies that the spatial and temporal 18o variations of rainwater in east asian monsoon regions have similar 18o t p relationships and the authigenic carbonates in chinese loess paleosol sequences can serve as valid records of 18op as an application of the 18o t p relationship p variation in the past 130 ka in luochuan was evaluated the reconstructed p is in good agreement with other studies using different approaches our results suggest higher precipitation in marine isotope stages 1 3 and 5 reflecting intense summer monsoon influences during these periods of time

laterally constrained inversion of ground roll from seismic reflection records seismic reflection data contain surface waves that can be processed and interpreted to supply shear wave velocity models along seismic reflection lines the coverage of seismic reflection data allows the use of automated multifold processing to extract high quality dispersion curves and experimental uncertainties in a moving spatial window the dispersion curves are then inverted using a deterministic laterally constrained inversion to obtain a pseudo 2d model of the shear wave velocity a monte carlo global search inversion algorithm optimizes the parameterization when the strategy is used with synthetic and field data consistent final models with smooth lateral variations are successfully retrieved this method constitutes an improvement over the individual inversion of single dispersion curves

oxygen and hydrogen isotopes in the hydrologic cycle changes of the isotopic composition of water within the water cycle provide a recognizable signature relating such water to the different phases of the cycle the isotope fractionations that accompany the evaporation from the ocean and other surface waters and the reverse process of rain formation account for the most notable changes as a result meteoric waters are depleted in the heavy isotopic species of h and o relative to ocean waters whereas waters in evaporative systems such as lakes plants and soilwaters are relatively enriched during the passage through the aquifers the isotope composition of water is essentially a conservative property at ambient temperatures but at elevated temperatures interaction with the rock matrix may perturb the isotope composition these changes of the isotope composition in atmospheric waters surface water soil and groundwaters as well as in the biosphere are applied in the characterization of hydrological system as well as indicators of paleo climatological conditions in proxy materials in climatic archives such as ice lake sediments or organic materials

oxygen isotope variations in phosphate of biogenic apatites ii phosphorite rocks abstract phosphorites from sedimentary sequences ranging in age from archaean to recent were analysed for 18 o in both the po 4 18 o p and co 3 18 o c in the apatite lattice the oxygen isotope record is considerably better preserved in phosphates than in either carbonates or cherts the use of the longinelli and nuti 8 temperature equation yields temperatures for recent phosphorites that are in good agreement with those measured in the field the 18 o p values of ancient phosphorites decrease with increasing age these changes with time are not likely to be due to post depositional exchange changes in 18 o values of seawater and variations of temperature with time can account for the 18 o p time trend but the latter explanation is preferred in ancient phosphorites 18 o c in structurally bound carbonate in apatite is not a reliable geochemical indicator

isotope compositions c o sr nd of vertebrate fossils from the middle eocene oil shale of messel germany implications for their taphonomy and palaeoenvironment abstract the middle eocene oil shale deposits of messel are famous for their exceptionally well preserved articulated 47 myr old vertebrate fossils that often still display soft tissue preservation the isotopic compositions o c sr nd were analysed from skeletal remains of messel s terrestrial and aquatic vertebrates to determine the condition of geochemical preservation authigenic phosphate minerals and siderite were also analysed to characterise the isotope compositions of diagenetic phases in messel diagenetic end member values of the volcanically influenced and due to methanogenesis 12 c depleted anoxic bottom water of the meromictic eocene maar lake are isotopically very distinct from in vivo bioapatite values of terrestrial vertebrates this unique taphonomic setting allows the assessment of the geochemical preservation of the vertebrate fossils a combined multi isotope approach demonstrates that enamel of fossil vertebrates from messel is geochemically exceptionally well preserved and still contains near in vivo c o sr and possibly even nd isotope compositions while bone and dentine are diagenetically altered enamel of the hippomorph perissodactyl propalaeotherium has low 13 c values 9 0 7 typical for c 3 plant feeders dentine of the same teeth has 13 c values 15 17 higher amongst the highest 13 c bioapatite values reported for terrestrial vertebrates this reflects diagenetic carbonate exchange with the strongly 12 c depleted anoxic lake bottom water enamel 87 sr 86 sr values 0 711 0 001 are consistent with propalaeotherium feeding on palaeozoic bedrocks surrounding lake messel and suggests that the basaltic tuff ring around the maar was already eroded 640 ka after its formation dentine has however much lower volcanically influenced 87 sr 86 sr 0 706 due to diagenetic sr uptake from the lake water oil shale enamel 18 o p values 18 0 6 of propalaeotherium are 2 3 lower than those of bones and scales of aquatic vertebrates that lived in the 18 o enriched lake water using transfer functions a 18 o h 2 o value of 5 1 for meteoric water and a mat of 18 2 5 c were reconstructed for messel

evidence for rapid climate change in north america during the latest paleocene thermal maximum oxygen isotope compositions of biogenic phosphate from the bighorn basin wyoming oxygen isotope records of cenozoic sea water temperatures indicate that a rapid warming event known as the latest paleocene thermal maximum lptm occurred during the otherwise gradual increase in world temperatures during the late paleocene and early eocene oxygen isotope analysis of the carbonate and phosphate components of hydroxyapatite found in mammalian tooth enamel and body scales of river dwelling fish from the bighorn basin in wyoming were made to investigate corresponding changes in the terrestrial climate a comparison of carbonate and phosphate isotope data from modern and fossil material indicates that some diagenetic alteration of the fossil material has occurred although systematically larger intra tooth ranges in the oxygen isotope composition of carbonate indicate that it is more likely to have been affected than phosphate carbonate and phosphate from the ecologically diverse mammals and fishes both record a shift to higher oxygen isotope ratios at the same time and of the same duration as the lptm these shifts reflect a change in the isotopic composition of regional precipitation which in turn provides the first evidence for continental climate change during the lptm assuming the present day relation between the oxygen isotope composition of precipitation and temperature applies to conditions in the past and that animal physiology and behavior is relatively invariant over time the isotopic shift is equivalent to an increase of surface temperature in western north america of several degrees this result is consistent with the magnitude of high latitude ocean warming and provides a basis for relating marine and terrestrial oxygen isotope records to records of terrestrial biotic change 1998 elsevier science b v all rights reserved

pliocene and early pleistocene paleoenvironmental conditions in the pannonian basin hungary slovakia stable isotope analyses of fossil proboscidean and perissodactyl teeth abstract stable carbon and oxygen isotope values of structural carbonate 13c 18oco3 and phosphate 18opo4 in bio apatite were measured for fossil mammalian teeth from slovakia and hungary oxygen isotope compositions of enamel provide new quantitative records of the pliocene and early pleistocene paleoclimate in the pannonian basin pb the 18opo4 values were used to study the temporal variations in the oxygen isotope compositions of precipitation and the changes in temperature over the pb the new o isotope data suggest that surface air temperatures between 4 5 and 2 0 ma were 1 to 4 c warmer with about 700 mm yr more precipitation compared to the present c isotope analyses of samples from proboscideans anancus sp mammut sp and perissodactyls stephanorhinus sp tapirus sp from the pliocene mn15 mn16 and early pleistocene mn17 suggest that they were primarily c3 browsers the mean 13c value is high at 4 5 to 3 7 ma mn14 15 during the pliocene warm period and decreases at about 3 5 to 3 0 ma mn16 mid pliocene warm period with the onset of more humid conditions in europe the 13c values return to higher values from 2 5 ma onwards mn17 most likely reflecting more arid conditions as a consequence of the onset of the northern hemisphere glaciation

a review of seismic geophysical testing in iran for building near surface velocity models abstract it has long been understood that the near surface structure of the earth affects several aspects of civil engineering practice particularly in seismic applications therefore the implementation of a competent subsurface exploration program not only addresses the need for comprehensive site characterization but also reduces the devastating consequences of seismic activities typical geotechnical practice for subsurface exploration has often relied on a combination of drilling in situ testing such as standard penetration testing and cone penetration testing and laboratory testing of field samples however geophysical techniques have been developed over the years to evaluate near surface velocity models as a proxy for subsurface stiffness in seismic applications in this regard seismic geophysical methods such as refraction reflection downhole and crosshole testing spectral analysis of surface waves sasw and multichannel analysis of surface waves masw have continued to receive increase

paleoclimatic inference from stable isotope profiles of accretionary biogenic hardparts a quantitative approach to the evaluation of incomplete data abstract variation in 18o of invertebrate and vertebrate skeletons has been widely employed to estimate annual means and seasonal ranges of temperature from many geologic settings among incertitudes encountered in employing this approach is the influence of unconstrained noise in environmental signals cessation of hardpart accretion during reproduction and or seasonal temperature extremes biasing of calculated mean temperatures toward seasons of maximum growth rate and dependence on the most extreme 18o values observed for estimating annual temperature range to better constrain paleoclimatic interpretations we describe several applications of a computational approach that address many of these uncertainties it is predicated on the presumption that annual variation in isotope composition across an accretionary skeleton represents sinusoidal variation in temperature and or the composition of ambient fluids the analysis resolves a best fit sinusoid for any portion of the data output consists of determinations of mean annual 18o seasonal range in 18o and sine period which reflects hardpart growth rate the procedure can be employed over some window of values within any data series and can be reiterated to arrive at solutions for all possible windows the technique allows for quantitative interpretation of mean values and annual amplitudes of 18o variation for every window regardless of whether or not that window actually spans a seasonal isotope extreme moreover it affords equal interpretational weight for every analysis in the data set in that mean annual and seasonal variation values estimated for each window are derived from every analysis in the data set it is therefore not necessary to estimate mean annual 18o as simply the arithmetic mean of all analyses and estimates of seasonality can be derived from data within any window rather than depending only on those several analyses that fall at compositional extremes in order to demonstrate the utility this methodology to the interpretation of paleoclimatological data we have applied it to published temperature data from several modern climatological data sets and to published 18o data from a paleogene gulf coast fish otolith a modern arabian sea coral a miocene texan equine tooth and an eocene bivalve from england each yields robust estimates of mean annual temperatures or isotopic compositions and of seasonal ranges in these values in addition unique features of data from each of these examples illustrate the power of this method to shed light on climatological and or biological phenomena that are also unique to each system

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

holocene and late pleistocene climate in the sub mediterranean continental environment a speleothem record from poleva cave southern carpathians romania the pp10 stalagmite from poleva cave provides a late pleistocene and holocene isotopic record characteristic for the sw of romania a sub mediterranean climatic region the speleothem was dated by eight tims and one alpha u series dates which showed that it was precipitated between 75 ka and 2 ka with at least two hiatuses the basal sector of the stalagmite showed a slow growing regime of 0 26 cm ka while the upper one grew relatively fast with about 5 cm ka the temporal resolution for the isotopic sampling is thus 2 ka sample for the lower sector and 150 years sample for the upper one the relationship between 18 o and temperature was found positive the isotopic record of the lower sector shows two marked cold intervals during 67 and 58 ka and 40 35 ka respectively which correlate well with the villars and soreq records the upper sector record is so far the most detailed holocene isotopic record in romania and the only one available for the regions located at the exterior of the carpathians range the signal shows a gradual warming after the gs1 event punctuated by several cold events at 8 7 2 and 4 2 ka and also by warm oscillations centered at about 5 2 and 3 3 ka the results seem to indicate that if the north atlantic firstorder signals may extend well to the south eastern europe their amplitude and general trend may be diminished by the interferences with the mediterranean circulation

volcanism and paleoenvironment of the pula maar complex a pliocene terrestrial fossil site in central europe hungary abstract we describe the late pliocene paleoenvironment and paleoclimate of the pula fossil site of the western pannonian basin hungary which occurs within a lacustrine succession deposited in a volcanic crater maar radiometric dating of adjacent volcanic bodies hosting the fossil bearing sedimentary assemblages gives an age of 4 25 0 17 ma k ar to date five articulated rhinoceros skeletons dihoplus sp have been recovered and a few fragmentary remains of artiodactyls and freshwater fishes perca sp leuciscus sp and gobius sp are also present an insect taphocoenosis comprises terrestrial groups that inhabited the former lake margins syrphidae heteroptera chalcidoidea tenebrionidae as well as aquatic insects dytiscidae baetidae and chironomidae deciduous broad leaved woody plants prevailed in and around the pula locality quercus ulmus zelkova acer salicaceae and are associated with some rare floral elements ginkgo sassafras and buxus deposition at the lake bottom seems to have taken place in oxygen depleted layers and taphonomic evidence indicates that fossil material underwent minimal if any weathering 13c values of one rhinoceros tooth suggest that this mammal consumed mixed c3 plants in a wooded environment the climatic conditions inferred from the reconstructed vegetation and stable oxygen isotope data from the tooth enamel support a cf type climate koppen classification with a mean annual temperature of 10 13 c with some dry periods during the year pula is comparable to other maar fossil sites of pliocene age such as camp dels ninots spain and hajnacka i slovakia

earth surface evaporative process a case study from the great lakes region of the united states based on deuterium excess in precipitation abstract the deuterium excess parameter in rain defined as d d 8 18o is a powerful geophysical tool which can be used to estimate secondary processes that influence atmospheric vapor content in the evaporation condensation cycle in nature the d excess has been calculated based on the systematic analysis of the stable oxygen and hydrogen isotope ratios in precipitation samples from kalamazoo southwest michigan the results show that moisture derived from the evaporation of lake michigan contributes between 9 16 during the summer months to the atmospheric vapor load in the region admittedly this estimate is an upper value since in our model we have assumed that transpiration from leaf surfaces is minimal compared to the evaporation from lake michigan it is therefore obvious that large freshwater systems need to be regarded as a potentially significant source of atmospheric vapor load isotopic investigations such as this will enable to attain quantitative estimates of this important aspect a knowledge of which will enhance the usefulness of or perhaps even be essential in calculations based on many atmospheric circulation models

middle late cretaceous climate of the southern high latitudes stable isotopic evidence for minimal equator to pole thermal gradients a detailed 18 o and 13 c stratigraphy has been generated from analysis of well preserved albian early maastrichtian foraminifera from deep sea drilling project dsdp sites 511 and 327 falkland plateau 58 s 62 s paleolatitude in the southern south atlantic and cenomanian and coniacian santonian foraminifera from dsdp site 258 naturaliste plateau 58 s paleolatitude in the southern indian ocean these results when combined with previously published maastrichtian stable isotope data from ocean drilling program odp site 690 weddell sea 65 s paleolatitude provide new insight into the climatic and oceanographic history of the southern high latitudes during middle late cretaceous time the planktonic foraminifer 18 o curves reveal a gradual warming of surface waters from the albian through the cenomanian followed by extremely warm surface waters from the turonian through the early campanian long term cooling of surface waters began in the late early campanian and continued through the end of the maastrichtian the benthic foraminifer 18 o record generally parallels changes in the oxygen isotopic curves defined by shallow dwelling planktonic foraminifera the vertical oxygen and carbon isotopic gradients were relatively low during the albian cenomanian high from the turonian early campanian and then low during the late campanian and maastrichtian foraminiferal oxygen isotopic data from published sources and this study are averaged for each site corrected for latitudinal changes in salinity based on modern day surface water values and plotted versus paleolatitude for the late albian coniacian santonian and late maastrichtian differences between lowand high latitude surface water paleotemperatures are estimated at 14 c during the late albian and late maastrichtian but the coniacian santonian reconstruction reveals only a 0 4 c latitudinal temperature gradient uncertainty regarding cretaceous salinity gradients and possible diagenetic alteration of 18 o values introduce error into our estimates of paleolatitudinal thermal gradients however apparent low equator to pole temperature differences could indicate much higher poleward heat transport than at present

global climate perturbations during the permo triassic mass extinctions recorded by continental tetrapods from south africa several studies of the marine sedimentary record have documented the evolution of global climate during the permo triassic mass extinction by contrast the continental records have been less exploited due to the scarcity of continuous sections from the latest permian into the early triassic the south african karoo basin exposes one of the most continuous geological successions of this time interval thus offering the possibility to reconstruct climate variations in southern laurasia from the middle permian to middle triassic interval both air temperature and humidity variations were estimated using stable oxygen 18op and carbon 13cc isotope compositions of vertebrate apatite significant fluctuations in both 18op and 13cc values mimic those of marine records and suggest that stable isotope compositions recorded in vertebrate apatite reflect global climate evolution in terms of air temperature oxygen isotopes show an abrupt increase of about 8 c toward the end of the wuchiapingian this occurred during a slight cooling trend from the capitanian to the permo triassic boundary ptb at the end of the permian an intense and fast warming of 16 c occurred and kept increasing during the olenekian these thermal fluctuations may be related to the emeishan south china and siberian volcanic paroxysms that took place at the end of the capitanian and at the end of the permian respectively vertebrate apatite 13cc partly reflects the important fluctuations of the atmospheric 13c values the differences with marine curves being likely due to the evolution of local humidity both the oxygen and carbon isotope compositions indicate that the ptb was followed by a warm and arid phase that lasted 6 ma before temperatures decreased during the late anisian toward that of the end permian environmental fluctuations occurring around the ptb that affected both continental and marine realms with similar magnitude likely originated from volcanism and methane release

cool tropical temperatures shift the global δ18o t relationship an explanation for the ice core δ18o borehole thermometry conflict the discrepancy between central greenland borehole temperatures and the isotopic composition of last glacial maximum ice can be explained by a shift in the 5180 t relationship for the hydrological cycle linked to cooler tropical temperatures this concept is illustrated using a simple rayleigh distillation model an estimate for o a 5180 at lgm holocene of 0 37 o oc is determined with a simple graphical technique

retrieving lateral variations from surface wave dispersion curves surface wave analysis is usually applied as a 1d tool to estimate v s profiles here we evaluate the potential of surface wave analysis for the case of lateral variations lateral variations can be characterized by exploiting the data redundancy of the ground roll contained in multifold seismic data first an automatic processing procedure is applied that allows stacking dispersion curves obtained from different records and which retrieves experimental uncertainties this is carried out by sliding a window along a seismic line to obtain an ensemble of dispersion curves associated to a series of spatial coordinates then a laterally constrained inversion algorithm is adopted to handle 2d effects although a 1d model has been assumed for the forward problem solution we have conducted different tests on three synthetic data sets to evaluate the effects of the processing parameters and of the constraints on the inversion results the same procedure applied to the synthetic data was then tested on a field case both the synthetic and field data show that the proposed approach allows smooth lateral variations to be properly retrieved and that the introduction of lateral constraints improves the final result compared to individual inversions

stable isotope geochemistry of carbonate minerals in supergene oxidation zones of zn pb deposits abstract the 18 o 16 o and 13 c 12 c ratios of carbonate minerals formed by supergene oxidation of zn pb deposits and submarine alteration of ancient slags were studied in order to constrain isotope fractionation factors for smithsonite cerussite and phosgenite and to characterize conditions of nonsulfide ore formation we present new isotope data of carbonate hosted ores from the iglesiente district sardinia italy and vila ruiva portugal as well as from the silicate hosted ores of the broken hill district new south wales australia and freihung germany and review previously published isotope data the temperature dependence of oxygen isotope fractionation between pb and zn carbonate minerals and water below 240 c for cerussite and below 100 c for smithsonite and phosgenite can be expressed as 1000ln cerussite water 2 29 10 6 t 2 3 56 1000ln smithsonite water 3 10 10 6 t 2 3 50 1000ln phosgenite water 2 55 10 6 t 2 3 50 with t in kelvin the carbon isotope fractionation between smithsonite phosgenite hydrozincite and calcite is less than about 2 while cerussites are strongly depleted in 13 c by about 10 as compared to the former minerals oxygen isotope variations of individual carbonate minerals within a deposit are relatively small indicating constant formation temperatures and a single meteoric fluid source average formation temperatures of the studied deposits are calculated at 20 5 c using the estimated isotope compositions of local paleometeoric waters we observe a linear relationship between the isotope values of estimated paleometeoric waters and supergene carbonates thus base metal carbonate minerals from supergene deposits may provide paleoclimatic information the carbon isotope values are in most carbonate hosted deposits highly variable more than 10 suggesting at least two isotopically distinct carbon sources the isotopically light component can be related to oxidation of c3 plants soil derived carbon and or microbes that take active part in sulfide oxidation while the isotopically heavy component originates from carbonate carbon from wall rocks and or atmospheric carbon the 13 c enriched component is less dominant in silicate hosted deposits

constrained 1d joint inversion of seismic surface waves and p refraction traveltimes we present a joint inversion scheme that couples p wave refraction and seismic surface wave data for a layered subsurface an algorithm is implemented with a damped least squares approach the estimated parameters are s and p wave velocities and layer thicknesses while densities are assumed constant during inversion the coupling is both geometric and physical layer thicknesses are the same for sand p wave velocity profiles and p wave velocities enter in both forward algorithms sensitivity analysis performed on synthetic data reveals that surface wave dispersion curves can be sensitive also to p wave velocity of some layers especially for poisson s ratio values smaller than about 0 35 allowing synergic resolution of this parameter applications on both synthetic and field data show that the proposed approach mitigates the hidden layer problem of seismic refraction and leads to more accurate results than individual inversions also for surface waves additional constraints on the objective function on a priori poisson s ratio values allow unrealistic and not admissible vp and vs values to be avoided such constraints were applied in one field case considering the a priori information available about water table depth it is also shown that estimation of porosity can help the selection of the proper constraint on a priori poisson s ratio

paleobiology and skeletochronology of jurassic dinosaurs implications from the histology and oxygen isotope compositions of bones fossil biogenic phosphate of fast growing primary bone tissue of dinosaurs can preserve a histologic and isotopic time series of annual seasonality in temperature variations similar to tooth enamel and other accretionary skeletal phases such as corals or wood on two bone fragments from sympatric dinosaurs with different histologic patterns of bone growth high resolution oxygen isotope profiles were analyzed along the radial direction of bone growth the investigated specimens are from the jurassic shishugou formation in the junggar basin nw china and have distinct patterns of compositional variation a fibrolamellar dinosaur bone with multiple lines of arrested growth lags and periodic growth cycles of decreasing bone laminae thickness displays a cyclic intra bone variation in 18o values of about 2 corresponding with the lags these growth cycles in fast growing fibrolamellar bone provide evidence for seasonal growth of dinosaurs in lower latitudes 45 n possibly influenced by a monsoon type paleoclimate seasonal changes in temperature and water supply are consistent with the oxygen isotope composition measured in dinosaur bone phosphate as well as with growth rings in contemporaneous fossil conifer wood from the same locality in contrast a plexiform sympatric sauropod bone displays continuous growth free of lags and has a lower intra bone variation of 0 8 differences in bone histology are also reflected in the oxygen isotopic composition and its intra bone variability indicating different physiological responses to external climatic stress between sympatric dinosaur species seasonal intra bone oxygen isotope variations combined with bone histology may thus yield new insights into species specific response to climatic stress and its influence on dinosaur growth formation of growth marks growth rates as well as dinosaur thermophysiology

stable oxygen δ18o and hydrogen δd isotopes in ovicaprid dentinal collagen record seasonal variation abstract understanding paleoenvironmental conditions including the frequency and amplitude of seasonal variation is crucial to understanding a wide array of human behaviors in prehistory in vertebrate calcified tissue inorganic oxygen isotopes derived from apatite have been widely used as a proxy for paleoenvironment and seasonality in the archaeological record however organic sources of 18 o and d in mineralized tissue have remained largely unexplored here we measure the oxygen 18 o and hydrogen d composition of dentin collagen sequentially sampled from the lower cheek teeth of four modern ovicaprids from the baga gazar in chuluu bgc region of the gobi desert of mongolia a significant correlation between trends in hydrogen and oxygen isotope values within individual teeth was identified the amplitude of isotopic variation observed in sampled tooth dentin is similar to the yearly range of hydrogen and oxygen isotopic variation observed in meteoric precipitation for the region these data indicate that dentin collagen 18 o and d isotopic values reflect seasonal variation in the organic oxygen and hydrogen isotopic composition of diet and ingested water we argue that paired measurements of dentin collagen 18 o and d appear to be reliable seasonal climatic indicators

oxygen isotope variations in phosphate of biogenic apatites i fish bone apatite rechecking the rules of the game abstract the major advantage of the oxygen in phosphate isotope paleothermometry is that it is a system which records temperatures with great sensitivity while bone and teeth building organisms are alive and the record is nearly perfectly preserved after death fish from seven water bodies of different temperatures 3 23 c and different 18 o values 16 to 3 of the water were analysed the 18 o values of the analysed po 4 vary from 6 to 25 the system passed the following tests a the temperatures deduced from isotopic analyses of the sequence of fish from lake baikal are in good agreement with the temperatures measured in the thermally stratified lake b the isotopic composition of fish bone phosphate is not influenced by the isotopic composition of the phosphate which is fed to the fish but only by temperature and water composition isotopic analysis of fossil fish in combination with analysis of mammal bones should be a useful tool in deciphering continental paleoclimates

characterisation and isotopic evolution of saline waters of the outokumpu deep drill hole finland implications for water origin and deep terrestrial biosphere abstract the isotopic composition of water and dissolved sr as well as other geochemical parameters at the 2516 m deep outokumpu deep drill hole finland were determined the drill hole is hosted by palaeoproterozoic turbiditic metasediments ophiolite derived altered ultramafic rocks and pegmatitic granitoids sodium ca cl and ca na cl rich waters total dissolved solids up to ca 70 g l 1 containing significant amounts of gas mainly ch 4 up to 32 mmol l 1 n 2 up to 10 mmol l 1 h 2 up to 3 1 mmol l 1 and he up to 1 1 mmol l 1 discharge from fracture zones into the drill hole this water is distinct from the shallow fresh groundwater of the area and has an isotopic composition typical of shield brines that have been modified during long term water rock interaction based on water stable isotopes and geochemistry the drill hole water profile can be divided into five water types each discharging from separate fracture systems and affected by the surrounding rocks the 2 h varies from 90 to 56 vsmow and 18 o from 13 5 to 10 4 vsmow plotting clearly above the global and local meteoric water lines on a 2 h vs 18 o diagram the 87 sr 86 sr ratios range between 0 72423 and 0 73668 simple two component mixing between 2 h and 18 o rich end member brine and meteoric water cannot explain the water stable isotopic composition and trends observed instead hydration of silicates by ancient groundwaters recharged under different climatic conditions warmer than at present is the most likely mechanism to have caused the variation of the 2 h and 18 o values water types correlate with changes in microbial communities implying that different ecosystems occur at different depths the different water types and microbial populations have remained isolated from each other and from the surface for long periods of time probably tens of millions of years

a new stable isotope record of neogene paleoenvironments and mammalian paleoecologies in the western great plains during the expansion of c4 grasslands abstract stable isotopes in horse teeth from the north american great plains show that equids began to incorporate c4 plants in their diets about 6 5 million years ago as c4 grasslands expanded however the ecological response of many other ungulates to this expansion is poorly documented we use stable carbon isotopes in mammalian tooth enamel to test whether other ungulates adapted by incorporating c4 vegetation in their diets the openness of habitats before the expansion of c4 grasslands is uncertain with plant phytolith studies suggesting a patchy environment with open habitat grasses and forest and pollen and macrofloral studies suggesting more forested habitats to address this problem we use a model that predicts carbon isotope values for tooth enamel for a variety of environments based on values in modern plants carbon and oxygen isotopes were analyzed in medium to large herbivores from three late miocene and three pliocene local faunas comprising a total of 13 and 7 genera respectively and 59 and 42 individuals results indicate that before the expansion of c4 grasslands taxa with high crowned teeth were consuming predominantly c3 vegetation in contrast by the late pliocene most taxa studied were consuming a component of c4 vegetation and only the peccary platygonus sp had a pure c3 diet c4 consumption increased in the late pliocene 3 0 ma big springs local fauna probably in response to increased c4 biomass most landscapes in the late miocene of nebraska were open such as woodland savanna or c3 grassland although low carbon values from the pratt slide local fauna suggest a denser presumably forested area this general pattern suggests an expansion of open habitats no later than 12 ma early clarendonian through the miocene pliocene transition there was an overall shift to lower 18o enamel values which parallels the long term decrease in global mean annual temperature inferred from the marine record our results indicate that major changes in the diets of medium and large herbivores broadly corresponded with increased c4 biomass and cooling climate from the latest miocene to the late pliocene

reconstructing the paleoenvironment of east central europe in the late pleistocene using the oxygen and carbon isotopic signal of tooth in large mammal remains abstract stable carbon and oxygen isotope values 13 c 18 o of structural carbonate were determined in the bioapatite component of fossil teeth from the czech republic slovakia and hungary oxygen isotope compositions of enamel and dentin samples provide new quantitative records of the late pleistocene climate in east central europe ece these 18 o data were combined with records of oxygen isotope values of recent and paleogroundwaters to study the spatial patterns and temporal variations in the oxygen isotope composition of precipitation and the thermal climate over ece the new isotopic data suggest that surface air temperatures in the study region between 33 and 12 ka were 2 9 c colder than present specimens of woolly mammoth rhino and horse from the late pleistocene were primarily c 3 grazers

oxygen and hydrogen isotopic ratios of water in precipitation beyond paleothermometry paleoclimatologists face a dilemma no sedimentary proxy is a pure recorder of quantitative climate information yet climate modelers and policy makers increasingly seek quantitative comparisons between instrumentally documented possibly anthropogenic climate changes and those produced naturally in the past in the second edition of his influential book bradley 1999 p 6 discussed the calibration of proxy records to learn past climate changes calibration involves using modern climatic records and proxy materials to understand how and to what extent proxy materials are climate dependent it is assumed that the modern relationships observed have operated unchanged throughout the period of interest the principle of uniformitarianism in other words one relates the characteristics of sediment to climate at different places for one time or at a place for short times and then uses that relation plus characteristics of older sediments to estimate the climatic conditions that produced those sedimentary characteristics bradley 1999 then extensively discussed the difficulties in applying this methodology in a complex world with imperfect recorders nonetheless the goal of using calibrated proxies for quantitative as well as qualitative paleoclimatic reconstruction is clear a prominent recent use of calibrated paleoclimatic data is the assessment of whether the probably anthropogenic warming of the latter 20th century moved beyond the band of natural variability of the prevailing climate bradley 2000 combined recent instrumental records with several longer proxy based reconstructions of surface temperature including that of mann et al 1999 based on this composite data set bradley 2000 argued that temperatures in the late 20th century were unique in the context of the entire millennium the proxy records were primarily based on tree ring data but included isotopic and major element geochemistry of corals and occurrence of melt layers and isotopic ratios of water in ice cores however broecker 2001 questioned the basis for the reconstruction of

stable isotopic and geochemical identification of groundwater evolution and recharge sources in the arid shule river basin of northwestern china stable isotopic dvsmow and 18ovsmow and geochemical signatures were employed to constrain the geochemical evolution and sources of groundwater recharge in the arid shule river basin northwestern china where extensive groundwater extraction occurs for agricultural and domestic supply springs in the mountain front of the qilian mountains the yumen tashi groundwater ytg and the guazhou groundwater gzg were ca hco3 ca mg hco3 so4 and na mg so4 cl type waters respectively total dissolved solids tds and major ion mg2 na ca2 k so42 cl and no3 concentrations of groundwater gradually increase from the mountain front to the lower reaches of the guazhou basin geochemical evolution in groundwater was possibly due to a combination of mineral dissolution mixing processes and evapotranspiration along groundwater flow paths the isotopic and geochemical variations in melt water springs river water ytg and gzg together with the end member mixing analysis emma indicate that the springs in the mountain front mainly originate from precipitation the infiltration of melt water and river in the upper reaches the lateral groundwater from the mountain front and river water in the middle reaches are probably effective recharge sources for the ytg while contribution of precipitation to ytg is extremely limited the gzg is mainly recharged by lateral groundwater flow from the yumen tashi basin and irrigation return flow the general characteristics of groundwater in the shule river basin have been initially identified and the results should facilitate integrated management of groundwater and surface water resources in the study area copyright 2015 john wiley sons ltd

bison bonasus skull from the bihor mountains romania isotopic and morphological investigations in this study we investigated morphologically and geochemically a skull from an open pit situated on the c lineasa esu g rzii plateau bihor mountains the study presents the first 14c dating and stable isotope composition of bison skeletal remains from the romanian carpathians the result of 14c determination yielded two relevant maxima one is around ad 1550 and the second around ad 1645 the data indicate that the investigated bison died during the little ice age lia approximately 200 years before the last ones were hunted to extinction stable isotope composition of carbon from bison tooth enamel suggests that the bison diet consisted mainly of c3 grasses compatible with a high altitude habitat vegetation distribution and low mobility oxygen isotope composition of both phosphate and carbonate groups of tooth enamel indicates that the bison drank from stagnant water sources such as lakes or puddles formed from rain water this further suggests low mobility of the bison as well as the presen

a case study of seismic zonation in municipal areas an earthquake of 7 4 magnitude in august 1999 caused major loss of life and severe damage within the municipality of izmit 170 km southeast of istanbul figure 1 a survey of the damaged buildings was made by the municipal authorities shortly after the earthquake the municipal government decided to conduct a pilot seismic zonation project to determine whether the cause of the damage was poor construction materials and methods or weak soil conditions in this project we investigated the soil conditions with two objectives in mind 1 to estimate the seismic model of the soil column at each district to determine the geotechnical earthquake engineering parameters and 2 to map active faults within the municipal area

stable isotope distribution in maastrichtian vertebrates and paleosols from the haţeg basin south carpathians abstract located in the south carpathians in romania the ha eg basin contains a thick sequence of maastrichtian continental deposits yielding a rich dinosaur and mammalian fauna stable isotope analyses of both calcretes and dinosaur crocodilian and turtle remains from two localities tustea and sibisel were integrated in order to reconstruct environmental conditions during maastrichtian time and to gain further insights into the metabolism and behaviour of the vertebrates the large difference observed between the 18o and 13c of the eggshells and the surrounding mudstones as well as the preservation of the 9 difference between the oxygen isotope composition of the telmatosaurus eggshell and tooth enamel indicate that diagenesis has not significantly altered the primary isotopic signal the presence of smectite in the fraction less than 2 m and the preservation of dinosaur eggshell structure also indicate that diagenesis was not significant in the studied outcrops stable isotope compositions of both calcretes and phosphatic remains suggest warmer conditions during the deposition of the tustea sequence mean annual temperature of around 14 c than during the deposition of the sibisel sequence mean annual temperature of 10 c the intra tooth 18o patterns for zalmoxes and allodaposuchus show different magnitudes of isotopic variation with lower values for tustea and higher for sibisel the calculated 18obody water enrichment for kallokibotion bajazidi is similar to that found in living turtle taxa by contrast in the case of allodaposuchus the isotopic enrichment is higher than for recent taxa this suggests that for allodaposuchus the body water was less buffered by a watery environment which probably indicates more time spent outside water i e more terrestrial habit the 18o values for the teeth of telmatosaurus and zalmoxes are similar to those of allodaposuchus suggesting that at the investigated sites the body temperature of both dinosaurs was similar to that of the crocodile the isotopic composition of calcretes teeth and eggshells indicates a c3 vegetation and diet with 13c values between 27 and 29 pdb and the absence of large scale habitat partitioning between the dinosaurs

site amplification assessment in the east corinth gulf using 3d finite difference modeling and local geophysical data elastic 3d wave field simulations were performed in the seismically active region of eastern gulf of corinth in the area of loutraki city a new methodology was tested with the aim of performing multiple simulations for a large variety of realistic sources located around the study area by employing 3d finite difference modeling using matrix operations for the calculation of the spatial velocity and stress derivatives the new methodology was proven to be quite efficient in simulating the near surface 3d site effect of the study area by greatly minimizing the simulation time thus allowing the use of 3d finite difference modeling for a large number of simulations the complex geological features of the study area were obtained by performing multiple passive masw surveys within the busy urban area of loutraki by processing the acquired geophysical data a highly inhomogeneous near surface velocity structure in the study area was obtained and was implemented in the 3d wave field simulations the near surface amplification that is caused by the 3d subsurface structure was proven to be highly significant for the area of loutraki with high spectral amplification compared to the amplification that is caused by an equivalent 1d model in the area the dominant frequencies of the spectral amplification for the 3d model were also confirmed by processing hvsr measurements that were also taken in the area finally we also investigated how the propagation direction affects the near surface amplification

effect of lateral heterogeneity in the soil column on shear wave velocity estimation by rayleigh wave inversion we conducted elastic wavefield modeling of shot gathers using soil column models with vertical and lateral velocity variations to study the dispersive behavior of rayleigh waves and the effect of lateral heterogeneity on the accuracy of rayleigh wave inversion for shear wave velocity estimation we also conducted a field experiment over an alluvial valley with soil column that thins out in the direction orthogonal to the valley axis from the model and field experiments we found that the dispersion characteristics of rayleigh waves are greatly influenced by the geometry of and lateral heterogeneities within the soil column nevertheless estimation of shear wave velocities within a soil column with lateral heterogeneity by rayleigh wave inversion is sufficiently robust and accurate for geotechnical applications

oxygen isotope and paleobotanical estimates of temperature and δ18o latitude gradients over north america during the early eocene empirical estimates of climate parameters such as mean annual temperature mat are essential to describe both ancient climate and to ground truth climate model simulations of past climates in terrestrial settings no single proxy record is able to provide detailed temporal yet geographically widespread information and it thus becomes essential that paleoclimatic information obtained from different proxies be comparable as an example of how to compare estimates and to illustrate what can be learned by doing so we measured oxygen isotope ratios of phosphate in the tooth enamel of fossil mammals and the body scales of freshwater fish in order to estimate the mean annual temperature mat in which they lived the samples were collected from paleogene rocks of the bighorn green river and powder river basins of wyoming earliest eocene samples provide mat estimates that are similar to mat estimates for the same times and areas obtained from leaf margin analysis furthermore isotopic data from the paleocene eocene thermal maximum petm which has not yet yielded fossil floras indicate a significantly higher mat of 26 c we also used temperature estimates obtained by both methods to investigate paleoelevation and to reconstruct geographic patterns of mat over north america for the early eocene larger laramide basins have higher temperatures and lower inferred elevations compared to associated volcanic highlands where cooler temperatures are consistent with substantial elevations in turn latitudinal gradients in temperature indicate that warming centered on polar regions played an important role during the eocene hothouse lastly we show that the reconstructed eocene relation between oxygen isotope ratios of precipitation and mat is significantly different from the modern relation between these two variables because the relation has changed over time the modern correlation should not be used to estimate paleo mat from measurements of oxygen isotope ratios in fossil material

environmental controls on the 2h 1h values of terrestrial leaf waxes in the eastern canadian arctic the hydrogen isotope composition of plant waxes preserved in lacustrine sediments is a potentially valuable tool for reconstructing paleoenvironmental changes in the arctic however in contrast to

stable isotope geochemistry and formation mechanisms of quartz veins extreme paleoaltitudes of the central alps in the neogene quartzveins ranging in size from less than 50 cm length and 5 cm width to greater than 10 m in length and 5 m in width are found throughout the central swiss alps in some cases the veins are completely filled with milky quartz while in others sometimes spectacular void filling quartz crystals are found the style of vein filling and size is controlled by host rock composition and deformation history temperatures of vein formation estimated using stable isotope thermometry and mineral equilibria cover a range of 450 c down to 150 c vein formation started at 18 to 20 ma and continued for over 10 my the oxygen isotope values of quartz veins range from 10 to 20 permil and in almost all cases are equal to those of the hosting lithology the strongly rock buffered veins imply a low fluid rock ratio and minimal fluid flow in order to explain massive nearly monomineralic quartz formation without exceptionally large fluid fluxes a mechanism of differential pressure and silica diffusion combined with pressure solution is proposed for early vein formation fluid inclusions and hydrous minerals in late formed veins have extremely low d values consistent with meteoric water infiltration the change from rock buffered static fluid to infiltration from above can be explained in terms of changes in the large scale deformation style occurring between 20 and 15 ma the rapid cooling of the central alps identified in previous studies may be explained in part by infiltration of cold meteoric waters along fracture systems down to depths of 10 km or more an average water flux of 0 15 cm3 cm 2yr 1 entering the rock and reemerging heated by 40 c is sufficient to cool rock at 10 km depth by 100 c in 5 million years the very negative d values of

oxygen isotopic composition of carbonate concretions from the lower cretaceous of victoria australia implications for the evolution of meteoric waters on the australian continent in a paleopolar environment oxygen isotopic data from carbonate cements in concretions have been used to infer the isotopic composition of meteoric fluids present at the time of concretion growth in terrestrial sediments that were deposited within the early cretaceous south polar circle at 75 80 s carbon and oxygen isotope compositions have been determined on over 135 samples of carbonate from 45 concretions taken from 24 localities aptian albian in age in the terrestrial sedimentary basins associated with the otway and strzelecki groups southeastern australia the carbonate cements include calcite having 26 4 13c 19 6and3 6 18o 29 6 or siderite having17 6 18o 30 8 calcite cemented concretions are more abundant and are interpreted to represent early near surface cementation events on the basis of textural evidence such as high 30 porosities at the time of cementation and mineralogical evidence such as the preferential preservation within concretions of labile detrital grains including plagioclase pyroxene and amphibole the oxygen isotopic data indicate that meteoric fluids with very low 18o certainly less than 15 and probably on the order of 20 were involved in the precipitation of the early calcites the extremely low 18o values of the fluids involved in the early diagenesis of both the otway and strzelecki groups suggest that the catchment area of the river system that carried sediments to these basins had a cold high latitude climate with mean annual temperatures less than 5 c and quite possibly below freezing by analogy with the relationship between modern18o distribution of meteoric fluids and climate these new data suggest that the early cretaceous polar regions may not have been ice free

stable isotope variations in stalagmites from northwestern sweden document changes in temperature and vegetation during the early holocene a comment on sundqvist et al 2007a we offer an alternative palaeoenvironmental interpretation of oxygen isotope data obtained on two early holocene stalagmite records from caves in the scandes mountains of northern sweden korallgrottan and labrintgrottan and the well known soylegrotta norway sg93 record with which they are compared that differs in several respects from that proposed by the authors contrary to viewing these as inverted palaeotemperature records we suggest that they primarily reflect changes in the delta o 18 of local annual precipitation modified by secondary temperature dependent variation in water calcite oxygen isotope fractionation at each of the three sites this is supported by the striking similarity over the entire holocene between the sg93 calcite delta o 18 record and the lacustrine carbonate delta o 18 record from lake tibetanus northern sweden which implies straightforward transfer of annual precipitation delta o 18 signals into cave drip waters recent studies of drip waters in korallgrottan also support this model this further enhances the value of cave deposits as palaeoclimate archives in this region and provides additional evidence of the sensitivity of the precipitation isotope thermometer to changes in atmospheric circulation patterns less

nonlinear refraction traveltime tomography a few important issues for performing nonlinear refraction traveltime tomography have been identified they include the accuracy of the traveltime and raypath calculations for refraction the physical information in the refraction traveltime curves and the characteristics of the refraction traveltime errors consequently we develop a shortest path ray tracing method with an optimized node distribution that can calculate refraction traveltimes and raypaths accurately in any velocity model we find that structure ambiguity caused by short and long rays in the seismic refraction method may influence the inversion solution significantly therefore we pose a nonlinear inverse problem that explicitly minimizes the misfits of the average slownesses ratios of traveltimes to the corresponding ray lengths and the apparent slownesses derivatives of traveltimes with respect to distance as a result we enhance the resolution as well as the convergence speed to regularize our inverse problem we use the tikhon

environmental influences on rabbit and hare bone isotope abundances implications for paleoenvironmental research abstract palaeoclimatological and palaeoenvironmental reconstructions based on stable isotope analysis of mammalian bone require an understanding of the behavior and physiology of the organism and mandate taxon specific considerations this study assesses the utility of using bone tissue of leporids cottontail rabbits sylvilagus sp and hares lepus sp as paleoenvironmental proxies leporids are globally widespread and commonly found in many archaeological middens in north america with material available in many museum collections we isolated and analyzed bone collagen and carbonate from 135 modern specimens from mexico and southern united states for light element stable isotope values of oxygen nitrogen and carbon stable isotope values were assessed with local ecoregion types for each specimen location and interpolated precipitation humidity and temperature variables reflecting the water acquisition strategies of leporids our results show significant negative correlations of bone 18o values with mean annual precipitation and with relative humidity contrary to expectations neither 13c nor 15n values are strong predictors of moisture variables which may be due to micro scale topographic and environmental variation and selective feeding strategies significant positive correlations are observed for 13c and 15n values with temperature variables our study increases our ability to model past environmental landscapes by considering how behavior ecology and environment interact to result in measured stable isotope values in leporid bones

paleoclimatic reconstruction using the correlation in δ18o of hackberry carbonate and environmental water north america abstract celtis sp commonly known as hackberry fruits were collected from 101 north american sites located in 13 states and one canadian province between the years of 1979 1994 the biomineralized carbonate endocarp of the hackberry which is a common botanical fossil found throughout the quaternary sediments of the great plains was analyzed for its 18o value and plotted against the 18o value of site environmental water to demonstrate the potential of the hackberry as a paleoclimate indicator this correlation was reinforced by intensive studies on extracted tissue water 18o value and hackberry endocarp carbonate 18o value from three trees in sterling colorado the observed correlation in the large data set between hackberry endocarp carbonate 18o value and environmental water is endocarp 18o 38 56 0 69 environmental water 18o r 0 88 r2 0 78 p value

carbon and oxygen stable isotope compositions of late pleistocene mammal teeth from dolines of ajoie northwestern switzerland abstract fossils of megaherbivores from eight late pleistocene 14 c and osl dated doline infillings of ajoie nw switzerland were discovered along the transjurane highway in the swiss jura carbon and oxygen analyses of enamel were performed on forty six teeth of large mammals equus germanicus mammuthus primigenius coelodonta antiquitatis and bison priscus coming from one doline in boncourt 80 ka marine oxygen isotope stage mis5a and seven in courtedoux 51 27 ka late mis3 in order to reconstruct the paleoclimatic and paleoenvironmental conditions of the region similar enamel 13 c values for both periods ranging from 14 5 to 9 2 indicate that the megaherbivores lived in a c 3 plant dominated environment enamel 18 o po4 values range from 10 9 to 16 3 with a mean of 13 5 1 0 n 46 mean air temperatures mats were inferred using species specific 18 o po4 18 o h2o calibrations for modern mammals and a present day precipitation 18 o h2o mat relation for switzerland similar average mats of 6 6 3 6 c for the deposits dated to 80 ka and 6 5 3 3 c for those dated to the interval 51 27 ka were estimated this suggests that these mammals in the ajoie area lived in mild periods of the late pleistocene with mats only about 2 5 c lower than modern day temperatures

stable isotope record implicates aridification without warming during the late capitanian mass extinction abstract the late capitanian mass extinction 260 million years ago represents one of the greatest biotic perturbations of the phanerozoic and was the earliest mass extinction to affect terrestrial tetrapods and ecosystems in the past this extinction has been largely associated with taxonomic loss and ecological restructuring in marine environments but more recently it has also been recognised in terrestrial ecosystems though various environmental mechanisms have been proposed for the former little evidence has yet been presented for the cause of terrestrial extinctions we determined the stable oxygen and carbon isotope compositions of dentine apatite from twenty eight specimens of the dicynodont therapsid diictodon feliceps to investigate the potential role of climate in driving terrestrial tetrapod extinctions studied specimens were recovered from a 270 m stratigraphic interval constraining the peak in tetrapod extinction rates in the uppermost abrahamskraal formation in the well sampled main karoo basin of south africa our results demonstrate a positive excursion of 13c values coinciding with the extinction peak that is followed by a return to pre extinction 13c values suggesting a local increase in aridity at the time of the extinction for the same time interval the 18o values did not demonstrate statistically significant changes suggesting constant temperature in the south african paleoenvironment this unusual increase in aridity but not in temperature has been interpreted as the possible result of orogenesis in the cape fold mountain source along the southern margin of gondwana

large arctic temperature change at the wisconsin holocene glacial transition analysis of borehole temperature and greenland ice sheet project ii ice core isotopic composition reveals that the warming from average glacial conditions to the holocene in central greenland was large approximately 15 c this is at least three times the coincident temperature change in the tropics and mid latitudes the coldest periods of the last glacial were probably 21 c colder than at present over the greenland ice sheet

applications of engineering seismology in urban areas i present two case studies which describe applications of engineering seismology in urban areas high resolution shallow offshore 3d seismic survey for the bosphorus subsea road tunnel project and seismic geotechnical and earthquake engineering site characterization for a residential project in istanbul in case study 1 i conducted a 3d high resolution shallow seismic survey in 2011 to confirm the geometry of the future bosphorus subsea road tunnel traverse i processed the data to obtain 3d pstm and psdm volumes and interpreted these image volumes and correlated the interpretation results with the offshore borehole data with the recoverable signal band of 30 960 hz i attained a vertical resolution of less than 1 m

the correlation between 18o 16o ratios of meteoric water and surface temperature its use in investigating terrestrial climate change over geologic time abstract correlations between mean annual temperature mat and the weighted average oxygen isotope composition of yearly precipitation 18opt are well known but the utility of modern relations to make reliable estimates of temperature change over geological time is uncertain this question has been addressed by using seasonal subsets of the global data base of temperature and isotopic measurements to represent two different climate modes a comparison of middle to high latitude 18opt temperature relations for each climate mode reveals 1 a significant offset between them and 2 a difference in the strength of their correlations the offset in relations is due to differences in temperature and water vapor budget in the tropics and can lead to serious underestimates of temperature change differences in the strength of correlations arise from the influence of climate mode specific non temperature factors on 18opt the overall result is that no single relation can be used in all cases to make unambiguous temperature estimates using a temporal record of 18opt values one way to overcome these problems is to reconstruct 18opt temperature relations for the time periods being investigated if an appropriate proxy for 18opt is available it may also be possible to estimate temperature without relying on 18opt temperature relations a promising alternative to these options is to use records of 18opt to test predictions of global climate models an approach that may allow a reliable and more complete reconstruction to be made of climate change over geologic time

isotopic evidence for shifts in atmospheric circulation patterns during the late quaternary in mid north america wyoming is now at the eastern margin of westerlies originating in the pacific but in the pleistocene appears to have received moisture from elsewhere possibly the gulf of mexico oxygen isotope ratios of pedogenic carbonate in postglacial terraces correspond to ratios in equilibrium with present meteoric waters which show a strong relation to precipitation seasonality and storm sources in contrast the oxygen isotope ratios of all pre holocene soils are significantly more positive even though the carbon isotope composition of coexisting organic matter suggests that the carbonate formed in temperatures cooler than today the oxygen isotope ratios of paleowaters in mid north america appear to be more useful for identifying past storm sources than for estimating paleotemperatures

seasonal variability in arctic temperatures during early eocene time abstract as a deep time analog for today s rapidly warming arctic region early eocene 52 53 ma rock on ellesmere island in canada s high arctic 79 n preserves evidence of lush swamp forests inhabited by turtles alligators primates tapirs and hippo like coryphodon although the rich flora and fauna of the early eocene arctic imply warmer wetter conditions than at present the quantification of eocene arctic climate has been more elusive by analyzing oxygen isotope ratios of biogenic phosphate from mammal fish and turtle fossils from a single locality on central ellesmere island we infer early eocene arctic temperatures including mean annual temperature mat of 8 c mean annual range in temperature of 16 5 19 c warm month mean temperature of 19 20 c and cold month mean temperature of 0 3 5 c our seasonal range in temperature is similar to the range in estimated mat obtained using different proxies in particular relatively high estimates of early eocene arctic mat and sst by others that are based upon the distribution of branched glycerol dialkyl glycerol tetraether gdgt membrane lipids in terrestrial soil bacteria and isoprenoid tetraether lipids in marine crenarchaeota fall close to our warm month temperature suggesting a bias towards summer values from a paleontologic perspective our temperature estimates verify that alligators and tortoises by way of nearest living relative based climatic inference are viable paleoclimate proxies for mild above freezing year round temperatures although for both of these reptilian groups past temperature tolerances probably were greater than in living descendants

climatic and environmental controls on speleothem oxygen isotope values variations in speleothem oxygen isotope values d 18 o result from a complicated interplay of environmental controls and processes in the ocean atmosphere soil zone epikarst and cave system as such the controls on speleothem d 18 o values are extremely complex an understanding of the processes that control equilibrium and kinetic fractionation of oxygen isotopes in water and carbonate species is essential for the proper interpretation of speleothem d 18 o as paleoclimate and paleoenvironmental proxies and is best complemented by study of site specific cave processes such as infiltration flow routing drip seasonality and saturation state and cave microclimate among others this review is a process based summary of the multiple controls on d 18 o in the atmosphere soil epikarst and speleothem calcite illustrated with case studies primary controls of d 18 o in the atmosphere include temperature and relative humidity through their role in the multiple isotope effects variability and modifications of water d 18 o values in the soil and epikarst zones are dominated by evaporation mixing and infiltration of source waters the isotopically effective recharge into a cave system consists of those waters that participate in precipitation of caco3 resulting in calcite deposition rates which may be biased to time periods with optimal dripwater saturation state recent modeling experimental and observational data yield insight into the significance of kinetic fractionation between dissolved carbonate phases and solid caco3 and have implications for the hendy test to assist interpretation of speleothem d 18 o time series quantitative and semi quantitative d 18 o climate calibrations are discussed with an emphasis on some of the difficulties inherent in using modern spatial and temporal isotope gradients to interpret speleothems as paleoclimate proxy records finally several case studies of globally significant speleothem paleoclimate records are discussed that show the utility of d 18 o to reconstruct past climate

paleoclimatic tracers an investigation using an atmospheric general circulation model under ice age conditions 2 water isotopes the linear relationship observed between the water isotopic contents of precipitation and surface air temperatures leads to the use of the water isotopes h218o and hdo in paleoclimatology applied to the measurements of the isotopic content of paleowaters like groundwaters and deep ice cores this relationship is used to infer paleotemperatures however this interpretation of paleo isotopic contents is only valid if the isotope temperature relationship is not affected by climate change to address this problem we have developed a water isotope modeling inside an atmospheric general circulation model agcm and performed simulations of both the present day and last glacial maximum lgm climatic conditions agcms are indeed the only appropriate tools able to account the whole complexity of the atmospheric circulation for the present day climate preliminary results for january were presented by joussaume et al 1984 and are complemented by new simulations performed for both february and august climatic conditions with a higher resolution version of the model model results are well corroborated by observations they also exhibit some effects of the atmospheric circulation on the isotopic fields for the simulated lgm climate the model results compare well with paleoclimatic data of water isotopic contents except for a higher than observed spatial variability the overall patterns of the simulated 18o temperature relationship for the lgm climate are practically unchanged which tends to comfort the use of water isotopes in paleoclimatology however concerning the deuterium excess i e the relationship between oxygen 18 and deuterium the model results are not sufficiently valid to allow a discussion of the use of deuterium excess in paleoclimatology

geographic provenance of aeolian dust in east antarctica during pleistocene glaciations preliminary results from talos dome and comparison with east antarctic and new andean ice core data abstract the strontium and neodymium isotopic signature of aeolian mineral particles archived in polar ice cores provides constraints on the geographic provenance of dust and paleo atmospheric circulation patterns data from different ice cores drilled in the centre of the east antarctic plateau such as epica dome c edc 75 06 s 123 21 e and vostok 78 28 s 106 48 e suggested a uniform geographic provenance for dust during pleistocene glacial ages likely from southern south america ssa in this work the existing dust isotopic data from edc have been integrated with new data from marine isotopic stage mis 14 about 536 ka before 1950ad and in parallel some first results are shown for the new taldice ice core which was drilled on the edge of the east antarctic plateau talos dome 72 48 s 159 06 e on the opposite side with respect to ssa interestingly the isotopic composition of taldice glacial dust is remarkably similar to that obtained from glacial dust from sites located in the east antarctic interior overall the glacial dust isotopic field obtained from six east antarctic ice cores matches well south american data obtained from target areas in this respect it was recently suggested that dust exported long range from south america originates from patagonia and from the puna altiplano plateau to test this hypothesis we analysed the isotopic composition of dust from an ice core drilled on the illimani glacier bolivia 16 37 s 67 46 w 6350 m a s l in order to obtain information on the isotopic composition of regional mineral aerosol uplifted from the altiplano area and likely transported over a long distance altogether ice core and source data strongly suggest that the westerly circulation pattern allowed efficient transfer of dust from south america to the east antarctic plateau under cold quaternary climates isotopic data support the hypothesis of a possible mixing of dust from patagonia and from the puna altiplano plateau interestingly high glacial dust inputs to antarctica are characterized by less radiogenic nd values an issue suggesting that enhanced dust production in patagonia was associated with the activation of a secondary source still patagonia was the most important supplier for dust to central east antarctica during quaternary glaciations