early stage sinkhole formation in the acque albule basin of central italy from geophysical and geochemical observations abstract sinkhole occurrence along the tyrrhenian margin of the central apennines is of great importance for applied research land management and civil protection this study reports on gps altimetry magnetic gravity geoelectric seismic and soil gas measurements of a rapidly developing sinkhole near the guidonia military airport the measurements revealed an elliptical 2 m depression elongated 220 m in the nne ssw direction with the minor axis of 110 m in the spring of 2013 two vertical cavities formed in the eastern and northeastern flanks of the depression whose depths and shapes are rapidly evolving with the formation of widespread fracturing along the same side the geophysical observations image the developing sinkhole to a depth of some 50 m the presence of the travertino lithotype around the depression down to at least 40 m and the lack of this lithotype below the lowered area the sinkhole s evolution appears to be structurally controlled by local and regional faulting these results are useful for designing further geophysical geotechnical and geochemical studies to monitor the sinkhole s evolution and to assess the hazard it presents in densely urbanized area

an interdisciplinary study of a mammoth bearing late pleistocene sediment succession in lower austria abstract in the alpine foreland and the vienna basin loess paleosol sequences lps are common some of the most famous lps sites in the circum alpine area include stratzing gottweig willendorf krems wachtberg and stillfried which cluster in a relatively small area along the danube river in lower austria lps provide detailed insights into climate driven terrestrial palaeoenvironmental changes that can be placed into a robust chronological framework because lps are amenable to a range of dating techniques here we present a well dated 13 6 m thick mammoth bearing sediment succession characterised by low energy aquatic deposits sheet flow deposits and sandy loess from re deposited miocene sediments i e a depositional environment that contrasts to the classical lps sites this new site is situated 1 6 km nne of bullendorf in lower austria where pleistocene sediment successions with a robust chronology are rare our multidisciplinary approach is based on optically stimulated luminescence and 14c dating and includes mammal faunal investigations and stable isotope analyses of molluscs osl and 14c dating suggest deposition of the sediment sequence immediately before and briefly after the last glacial maximum the mollusc assemblages and the mammal fauna are representative of a cold climate characteristic of a tundra steppe environment stratigraphic changes in 18o of two mollusc species pupilla muscorum and succinella oblonga suggest an alternating dry cold and humid cold climate oxygen isotope data of freshwater gastropod shells suggest a drastic decrease in the mean growing season temperature compared to today while the carbon isotope composition is indicative of a c3 vegetation

stable and clumped isotopes in shell carbonates of land snails cathaica sp and bradybaena sp in north china and implications for ecophysiological characteristics and paleoclimate studies knowledge of ecophysiological characteristics of different land snail species is crucial for defining climatic significance of snail faunal assemblages however little work has been done in this aspect hindering our obtaining unambiguous paleoclimatic information using these proxy indicators here we document for the first time the different ecophysiological characteristics of cathaica sp and bradybaena sp land snails using the stable isotopes and clumped isotope 47 of the shell carbonates the 47 derived temperatures for both species revealed a robust correlation with environmental temperatures moreover the temperatures for cathaica sp are 3 5 c higher than those for bradybaena sp land snails indicating different ecophysiological adaptations or growing seasons of the two species specifically cathaica sp snails prefer living in a warm humid summer whereas bradybaena sp snails are active in the relatively cool arid spring and or autumn the result testifies to the 47 in snail shell carbonates as a promising paleothermometer in monsoonal region and presents new insight into paleoclimatic explanation of these land snail species this finding highlights the importance of climatic seasonality in the changes of the faunal assemblages of land snails

stable isotope composition of late pleistocene holocene eobania vermiculata muller 1774 pulmonata stylommatophora shells from the central mediterranean basin data from grotta d oriente favignana sicily abstract this paper presents stable isotopic results oxygen and carbon from both modern and late pleistocene holocene shells of the land snail eobania vermiculata muller 1774 from favignana island sicily it aims to contribute to the understanding of climate and vegetation history of this region during formation of upper palaeolithic mesolithic and meso neolithic deposits of grotta d oriente ort results from both an evaporative model fbm and an empirical regional isotopic model i e linear relation between oxygen isotopic composition of shells 18 os and those of local precipitation 18 op indicate that the 18 os values of modern specimens are mainly controlled by local temperature relative humidity and 18 op at the time of snail activity data also suggest that the modern snails are nocturnally active almost all year round in the study area the carbon isotopic compositions of shells 13 cs of the same specimens indicate a diet prevalently or exclusively composed of c3 vegetation the 18 os values of late pleistocene specimens suggest that climate conditions at 14 2 ka cal bp were similar to the present day in agreement with additional 18 os records from southern italy by contrast early middle holocene shells are notably 18 o depleted and suggest wetter conditions possibly combined with a decrease in isotopic composition of precipitation source compared to the present day when compared with regional palaeoclimatic records a large scale isotopic response to millennial scale changes in atmospheric and hydrological conditions e g enhanced rainfall in the central eastern mediterranean is observed during the early middle holocene the 13 cs of late pleistocene and holocene specimens are consistently higher than those of modern ones for the late pleistocene this could be reasonably explained in terms of water stressed vegetation on the other hand this seems to be less valid for holocene counterparts when the climate was wetter probably 13 cs values result from the combination of distinct competing factors involving atmospheric co 2 concentration seasonal water budget vegetation type cover and other carbon sources results reveal coherent relationships between regional 18 os and 13 cs demonstrating that late pleistocene holocene land snail shell remains from archaeological sites may provide useful snapshots of past seasonal climate conditions

holocene trends in 18o in land snail shells from the negev desert and their implications for changes in rainfall source areas abstract the 18o value of the carbonate of land snail shells is related to the 18o content of precipitation which in turn relates to the source region and trajectory of the rain bearing air masses analyses of 18o of the shell carbonate of 76 radiocarbon dated holocene samples of the land snail trochoidea seetzeni from the northern negev desert in southern israel were carried out and the results were compared to modern snails from the same region early holocene 18o values are similar to modern but during the period centered around 6500 6000 yr b p a depletion of some 2 below modern is observed a change in the atmospheric circulation pattern for this period is thus indicated most likely an increase in the frequency of storm systems reaching the region from north eastern africa by 3500 yr b p 18o values had reached modern levels and indicate a stable pattern of atmospheric circulation since that time

the influence of diet on the δ13c of shell carbon in the pulmonate snail helix aspersa abstract the influence of diet and atmospheric co2 on the carbon isotope composition of shell aragonite and shell bound organic carbon in the pulmonate snail helix aspersa raised in the laboratory was investigated three separate groups of snails were raised on romaine lettuce c3 plant 13c 25 8 corn c4 plant 13c 10 5 and sour orange 12c enriched c3 plant 13c 39 1 the isotopic composition of body tissues closely tracked the isotopic composition of the snail diet as demonstrated previously however the isotopic composition of the acid insoluble organic matrix extracted from the aragonite shells does not track diet in all groups in snails that were fed corn the isotopic composition of the organic matrix was more negative than the body by as much as 5 whereas the matrix was approximately 1 heavier than the body tissues in snails fed a diet of c3 plant material these results indicate that isotopic composition of the organic matrix carbon cannot be used as an isotopic substrate for paleodietary reconstructions without first determining the source of the carbon and any associated fractionations the isotopic composition of the shell aragonite is offset from the body tissues by 12 3 in each of the culture groups this offset was not influenced by the consumption of carbonate and is not attributable to the diffusion of atmospheric co2 into the hemolymph the carbon isotopic composition of shell aragonite is best explained in terms of equilibrium fractionations associated with exchange between metabolic co2 and hco3 in the hemolymph and the fractionation associated with carbonate precipitation these results differ from previous studies based primarily on samples collected in the field that have suggested atmospheric carbon dioxide contributes significantly to the shell 13c the culture results indicate that the 13c of aragonite is a good recorder of the isotopic composition of the snail body tissue and therefore a better recorder of diet than is the insoluble shell organic carbon because the systematic fractionation of carbon isotopes within the snail is temperature dependent the 13c of the shell could provide an independent technique for estimating paleotemperature changes

holocene hydrological changes in south western mediterranean as recorded by lake level fluctuations at lago preola a coastal lake in southern sicily italy abstract this paper presents a high resolution lake level record for the holocene at lago preola sicily southern italy based on a specific sedimentological approach with a chronology derived from ams radiocarbon dates it gives evidence of three major successive palaeohydrological periods with 1 a pronounced dryness during the early holocene until ca 10300 cal bp 2 a highstand from ca 10300 to 4500 cal bp and 3 a marked lowstand from 4500 cal bp to present large amplitude lake level fluctuations characterise two transition phases at ca 10300 9000 and 6400 4500 cal bp period 2 was interrupted between 8300 and 7000 cal bp by a dry phase that was punctuated to ca 7300 cal bp by the deposition of a tephra from neighbouring pantelleria island comparisons of the preola record with other palaeohydrological records along north south and west east transects in the mediterranean show contrasting patterns of hydrological changes north south of around 40 n latitude the records highlight a mid holocene period characterised by lake level minima maxima humid mid holocene conditions over the mediterranean south of 40 n were probably linked to a strong weakening of the hadley cell circulation and of monsoon winds we suggest that the maximum of humidity in the mediterranean during the mid holocene was characterised by humid winters to the north of 40 n and humid summers to the south on a multi centennial scale the high resolution palaeohydrological reconstructions in the central mediterranean area reveal a strong climate reversal around 4500 4000 cal bp with contrasting changes in the hydrological cycle in addition to seasonal and inter hemispherical changes related to orbital forcing this major oscillation might be related to non linear responses of the climatic system to the gradual decrease in summer insolation at northern latitudes another major climate oscillation around 7500 7000 cal bp may have resulted from the combined effects of 1 a strong rate of change in insolation and 2 variations in solar activity finally comparisons of the preola lake level record with sicilian pollen records suggest a strong influence of moisture availability on vegetation development in sicily very dry early holocene conditions probably prevented the expansion of coastal evergreen forests while decreasing moisture availability since the onset of the late holocene may have exacerbated effects of intensive land use

oxygen isotope signatures from land snail helix melanostoma shells and body fluid proxies for reconstructing mediterranean and north african rainfall abstract in this paper we show that oxygen isotope ratios from the shell carbonate of the land snail helix melanostoma reflect local rainfall parameters stable oxygen isotopes were measured in the body fluid 18 o body and shells 18 o shell of live collected h melanostoma along a north south transect across the gebel akhdar in northeast libya 18 o body ranged between 8 1 and 13 0 whilst 18 o shell ranged between 1 0 and 2 8 to investigate the relationship between snail oxygen isotope composition and climate these measurements were correlated with ambient air temperature relative humidity rainfall amount and the 18 o composition of rainwater 18 o rain strong and significant correlations were found between 18 o shell and 18 o rain and between 18 o shell and rainfall amount r 2 0 79 and 0 85 respectively suggesting that h melanostoma shells can be used as a proxy for past rainfall conditions when combined in multiple linear regressions 18 o rain and rainfall amount explained 90 of the variance in 18 o shell r 2 0 90 simple and multiple linear regressions were used to develop predictive models for these climate parameters as h melanostoma shells are commonly found in mediterranean and north african archaeological and geological deposits the predictive equations developed in this study hold great potential for reconstructing pleistocene to holocene rainfall and aridity patterns in the gebel akhdar and for assessing the relationship between environmental changes and human behavioural changes

spt blow count vs shear wave velocity relationship in the structurally complex formations of the molise region italy abstract the relationship between the shear wave velocity vs and the blow number of the standard penetration tests nspt was investigated with reference to the structurally complex formations located in a wide sector of the southern apennine chain molise region italy novel nspt vs correlations were developed based on a balanced number of in situ tests coming from the seismic microzonation of the municipalities of campobasso district and the seismic vulnerability assessment of strategic road infrastructures it was proven that available relationships were not able to fit the data in the area of interest even making the analysis according to the soil grain size classification this circumstance was related to the nature of the geological formations which are chaotically built and affected by complex structural textural and lithological characteristics hence in this paper a rational methodology for an integrated geological and geotechnical assessment of the available field data based on lithostratigraphical features was presented and discussed three original empirical nspt vs power function relationships were derived and distinguished depending on the main lithofacies recognized in the campobasso district corresponding to structured soil deposit ssd all soils as and weathered soils ws their validation through statistical assessment of data confirmed the relevance of the results and the advantages related to their use at regional scale based on an integrated geological and geotechnical approach

evaluation of the lateral earth pressure coefficients at rest in granular soil deposits using the anisotropic components of s wave velocity abstract determination of the lateral earth pressure coefficients at rest k0 in natural soil deposits is an important issue in geotechnical and geological engineering in this study evaluation of this parameter in a granular soil deposit was examined by using two anisotropic components of the s wave velocity sv and sh wave components to this end thirteen pairs of p and s wave seismic refraction profiles were acquired at two different granular sites in iran the collected shot gathers were processed from which the sv and sh wave velocities were derived the sv wave velocities were obtained by using the multichannel analysis of surface waves masw method while the sh wave velocities were extracted by utilizing the multichannel analysis of love waves malw technique the reference k0 values in the soil deposits were calculated by the mayne and kulhawy s formula based on the friction angles and overconsolidation ratios ocr determined from laboratory tests the curves of the reference k0 values versus the sh sv velocity ratios at both sites strongly confirmed the feasibility of k0 evaluation from the velocity components to develop a global equation for k0 evaluation in granular soil deposits a general regression analysis was conducted on the obtained data from this study combined with those reported in the literature the results showed that reliable values of k0 can be estimated using the sh sv velocity ratios the findings of this study may appropriately serve as references for economic and non invasive in situ k0 identification in granular soil deposits using the surface wave methods

electrical resistivity tomography applied to geologic hydrogeologic and engineering investigations at a former waste disposal site a former dolerite quarry and landfill site was investigated using 2d and 3d electrical resistivity tomography ert with the aims of determining buried quarry geometry mapping bedrock contamination arising from the landfill and characterizing site geology resistivity data were collected from a network of intersecting survey lines using a wenner based array configuration inversion of the data was carried out using 2d and 3d regularized least squares optimization methods with robust l1 norm model constraints for this site where high resistivity contrasts were present robust model constraints produced a more accurate recovery of subsurface structures when compared to the use of smooth l2 norm constraints integrated 3d spatial analysis of the ert and conventional site investigation data proved in this case a highly effective means of characterizing the landfill and its environs the 3d resistivity model was successfully used to confirm the position of the landfill boundaries which appeared as electrically well defined features that corresponded extremely closely to both historic maps and intrusive site investigation data a potential zone of leachate migration from the landfill was identified from the electrical models the location of this zone was consistent with the predicted direction of groundwater flow across the site unquarried areas of a dolerite sill were imaged as a resistive sheet like feature while the fault zone appeared in the 2d resistivity model as a dipping structure defined by contrasting bedrock resistivities

geochemistry of rainfall at stromboli volcano aeolian islands isotopic composition and plume rain interaction the chemical and isotopic compositions of the precipitation at stromboli island italy were investigated between october 2003 and october 2005 we employed a rain gauge network designed to cover the range in exposures and elevations of the volcanic edifice the hydrogen and oxygen isotopic ratios vary greatly on a seasonal basis and correlate with air temperature deuterium excess values show a positive correlation with altitude no direct contribution of volcanogenic h or o is evident in the isotopic composition of the rainwater the chemical composition of the rainwater is principally controlled by the sea aerosol contribution at the coastal sites whereas it is significantly influenced by volcanic activity near the summit vents interaction with volcanic acid gases is indicated by the ph which is usually 1 2 units lower near the craters than at the coastal sites the s cl cl f and s f molar ratios in rainwater 1 5 km from the craters are consistent with those measured in the volcanic plume using other methods diffusive tubes and fourier transform infrared spectroscopy rising of undegassed magmas changes these molar ratios because of the differential degassing of sulphur chlorine and fluorine from the magma we therefore propose that the chemical composition of precipitation within 1 5 km of the craters provides additional information that is useful for monitoring volcanic activity at stromboli island moreover this paper presents estimates of the fluxes of f cl s na k ca and mg to the soil that could be useful for geochemical studies on groundwater

analysis of spatial variability of spt penetration resistance in collapsible soils considering water table depth abstract geostatistical kriging approach was used for mapping of water table depth and for checking its influence on penetration resistance observed in standard penetration test spt geostatistical mapping was based on a compartmentalisation of 204 spt records in two main groups using monthly and yearly rainfall marks as a segregation criterion six maps produced at 1 10 000 scale were achieved as follows water table depth variation and penetration resistance variation at the depths of 1 5 6 0 8 5 11 0 13 5 m greater variations of the penetration resistance in terms of increase and reduction of resistance were observed at the depths of 6 0 and 8 5 m

stacked 2 6 ma grain size record from the chinese loess based on five sections and correlation with the deep sea δ18o record 1 this study aims to establish a stacked climate record of the quaternary period from the chinese loess sequence and to address the forcing mechanisms for the regional climate history of the loess plateau by correlating the stacked record with a composite 18o record in deep sea sediments a total of 18 352 samples were obtained from five loess sections located at baoji lingtai jingchuan puxian and pingliang in the southern and middle loess plateau these yielded high resolution grain size records between section correlation of these shows that although small depositional hiatuses are present in places within a single section most parts of the sections display near continuous dust deposition throughout the quaternary the grain size records were tuned simultaneously to the theoretical variations in obliquity and precession of the earth s orbit the grain size records plotted on their orbital timescales were then averaged to form a stacked loess grain size time series termed the chiloparts record this resolves most of the orbital timescale paleoclimate events buried in the loess soil sequences of the southern and middle loess plateau and can be used as a regional archive of the pleistocene climate history in the loess plateau comparison of the chiloparts record with a composite marine 18o record shows that for the past 1 8 ma the loess paleosol record can be correlated almost cycle by cycle with the marine record several discrepancies in the climatic events between the two records have also been identified implying that regional forcing mechanisms may have played a part in the climatic evolution of the chinese loess plateau

late glacial to holocene transition in northern spain deduced from land snail shelly accumulations abstract shells of the helicid cepaea nemoralis were studied using taphonomic isotopic and morphometric measurements to estimate late glacial holocene 12 1 6 3 cal ka bp environmental conditions in northern spain higher taphonomic alteration among holocene shells suggests lower sedimentation rates or higher shell destruction rates than during glacial conditions shells preserved the aragonitic composition despite differing degree of skeleton damage shell 13 c values were 10 3 1 1 8 2 2 3 and 7 3 1 6 for modern holocene and late glacial individuals respectively higher 13 c values during the late glacial and some holocene periods imply higher water stress of c 3 plants and or higher limestone contribution than today intrashell 13 c values were higher during juvenile stages suggesting higher limestone ingestion to promote shell growth shell 18 o values were 1 1 0 7 0 9 0 8 and 0 1 0 7 for modern holocene and late glacial specimens respectively a snail flux balance model suggests that during 12 1 10 9 cal ka bp conditions were drier and became wetter at 8 4 6 3 cal ka bp and today intrashell 18 o profiles reveal that glacial individuals experienced more extreme seasonality than interglacial shells despite possible larger hibernation periods shell size correlated positively with 18 o values suggesting that growth rates and ultimate adult size of c nemoralis may respond to climate fluctuation in northern spain

stable isotope δ18o δ13c and δd signatures of recent terrestrial communities from a low latitude oceanic setting endemic land snails plants rain and carbonate sediments from the eastern canary islands abstract stable isotopes of oxygen and carbon extracted from fossil land snail shells have been used increasingly to interpret past environments to evaluate the utility of this approach for low latitude oceanic islands populations of the modern helicid land snail theba geminata a species also abundant in the quaternary fossil record of the region were sampled at ten low altitude d and 2 v smow for 18 o ranging from 11 to 2 v smow and from 2 6 to 0 7 v smow respectively the local vegetation is heterogeneous including c 3 c 4 and cam plants 13 c values vary from 13 0 to 29 0 v pdb across plant species of the 24 species five are c 4 15 are c 3 and four are cam plants the 18 o values for shells represent a narrow range of values from 0 3 to 2 5 v pdb which is consistent with the low climate seasonality typifying low latitude oceanic settings hypothetical model of the expected 18 o value for shell aragonite precipitated in equilibrium suggests that the most negative 18 o shell represent the closest estimate for 18 o rain water the 13 c values of shells range from 9 4 to 1 7 v pdb the most positive 13 c values are attributed to a diet based on c 4 plants the comparison of 13 c values of soft tissues and shells suggests that snails ingested notable amounts from 20 up to 40 of foreign carbonates consequently fossil shells with the most negative 13 c values should be selected for radiocarbon dating in future geochronological studies of the region the 13 c values of body tissues vary from 12 0 to 27 2 v pdb indicating that land snails consumed c 3 and c 4 plants indiscriminately the mean carbon isotopic composition averaged across multiple fossil specimens may thus provide a useful tool for reconstructing paleoclimates and paleoenvironments throughout the quaternary history of the canary islands and other comparable low latitude oceanic settings

study of the diet effect on δ13c of shell carbonate of the land snail helix aspersa in experimental conditions abstract this study aims to demonstrate the influence of the metabolic co2 derived from the diet and of the atmospheric co2 on the shell carbonate 13c of the pulmonate snail helix aspersa maxima raised under controlled conditions adult snails were analyzed and compared with three hatching and 1 day old young snails stemming from the same breeding one day after the 2 day old individuals were raised during 1 month three groups of gastropods were fed with fresh lettuce c3 plant 13c 27 49 three groups with corn c4 plant 13c 11 7 and three groups ate alternately both c3 c4 the difference between the average 13c values of the adult snails on the one hand and the hatched and 1 day old snails on the other hand indicates a depletion of 2 47 therefore the isotopic parents offspring signal is not preserved the depleted ingested albumen by the snail embryo in the egg during the building of the shell could explain this depletion the c3 diet experiment gave the expected isotopic composition difference between the diet lettuce and the shells average 13cshell lettuce 13 75 0 52 this result shows a clear diet effect on the isotopic composition of the snail shells for the c4 experiment the difference in carbon isotope composition between the corn and the shell 13cshell corn yielded an average value of 4 89 0 87 the main result is that 13c is not constant and appears to depend on the type of ingested food several hypotheses can arise from this study to explain the different fractionations a differences in the quality of the two diets b differences in turnover rate for c3 and c4 feeders the groups regularly fed with mixed diet yielded 13c values showing a preferential use of c3 food for most values the c3 c4 mixed dietary alternation probably led snails to use mainly the lettuce instead of the corn powder

middle pleistocene mis 14 environmental conditions in the central mediterranean derived from terrestrial molluscs and carbonate stable isotopes from sulmona basin italy abstract a paleosol from the middle pleistocene lacustrine fluvial succession of sulmona basin central italy was analysed for the land snail shell content and the stable isotope composition of the shells and associated pedogenic carbonates the paleosol known as fiorata paleosol is covered by a thick tephra layer dated to ca 527 ka allowing the pedogenetic horizons to be correlated to the marine isotope stage mis 14 early mis 13 interval the terrestrial mollusc assemblage contained few individuals and was characterized by a low number of species which predominantly indicate open and dry habitats thus suggesting that fiorata paleosol likely developed during glacial conditions of the mis 14 the 13 c values of pedogenic carbonates and terrestrial shells indicate prevailing c 3 type vegetation probably marked by some degree of water stress calculation of the 18 o precipitation values derived from pedogenic carbonates and shell 18 o values indicate that the average temperature was 3 5 c lower than present day this study highlights how paleosols despite offering only snapshots of past climate and environments provide valuable complementary information to paleoclimatic data obtained in the adjacent lacustrine intervals specifically for the sulmona successions

paleoclimatic implications of the spatial patterns of modern and lgm european land snail shell δ18o abstract the oxygen isotopic composition of land snail shells may provide insight into the source region and trajectory of precipitation last glacial maximum lgm gastropod shells were sampled from loess from belgium to serbia and modern land snail shells both record 18 o values between 0 and 5 there are significant differences in mean fossil shell 18 o between sites but not among genera at a single location therefore we group 18 o values from different genera together to map the spatial distribution of 18 o in shell carbonate shell 18 o values reflect the spatial variation in the isotopic composition of precipitation and incorporate the snails preferential sampling of precipitation during the warm season modern shell 18 o decreases in europe along a n s gradient from the north sea inland toward the alps modern observed data of isotopes in precipitation gnip demonstrate a similar trend for low altitude sites lgm shell 18 o data show a different gradient with 18 o declining toward the ene implying a mid atlantic source due to increased sea ice and a possible southern displacement of the westerly jet stream balkan lgm samples show the influence of a mediterranean source with 18 o values decreasing northward

oxygen isotope composition of living land snail shells data from italy sixty seven shells of living land snails were selected from 31 different localities across italy to investigate the relationships between their oxygen isotopic composition 18os and the mean value of local rainfall 18op despite the difficulty for some localities to correctly estimate the oxygen isotopic composition of local rainfall a good relationship was found this indicates that the oxygen isotopic composition of environmental water used by the snails is in italy strictly related to that of the local meteoric precipitation however the relationship found is substantially different from that previous established for central europe indicating that regional climatic conditions are important in defining the final isotopic composition of land snail shells moreover these equations may not hold for different climatic conditions existing during for instance glacial and interglacial periods the data also show that isotopic differences among species are relatively narrow and that they may depend on ecological factors i e style of life rather than any clearly identifiable different vital offset

stable isotope composition of land snail body water and its relation to environmental waters and shell carbonate abstract day to day and within day diel variations in d and 18 o of the body water of the land snail theba pisana were studied at a site in the southern coastal plain of israel three phases of variation which relate to isotopic changes in atmospheric water vapor were distinguished 1 on rain days snail water becomes isotopically depleted approximately in the direction of the rain isotope values but always less depleted in d as is atmospheric water vapor 2 during the 1 3 days following a rain the snail water becomes isotopically enriched along a line with slope 18 o space this relates to an increasing influence of humidity derived from the mediterranean sea 3 a period of relative stability of the isotopic composition persists until the next rain event the isotopic variations can be explained by isotopic equilibration with atmospheric water vapor and or uptake of dew derived therefrom during the winter when the snails are active there is only very minor enrichment in 18 o relative to equilibrium with water vapor or dew apparently as a result of metabolic activity but this enrichment becomes pronounced after long periods of inactivity within day variation in body water isotopic composition is minor on non rain days shell carbonate is enriched in 18 o by ca 1 2 relative to equilibrium with body water in most regions the isotopic composition of atmospheric water vapor or dew is a direct function of that of rain because the isotopic composition of snail body water is related to that of atmospheric water vapor and the isotopic composition of shell carbonate in turn is related to that of body water land snail shell carbonate 18 o should provide a reliable indication of rainfall 18 o however local environmental conditions and the ecological properties of the snail species must be taken into account

carbon isotope signatures from land snail shells implications for palaeovegetation reconstruction in the eastern mediterranean in this study we compare carbon isotope values in modern helix melanostoma shell carbonate 13cshell from the gebel al akhdar region of libya with carbon isotope values in h melanostoma body tissue 13cbody local vegetation 13cplant and soil 13csoil all vegetation in the study area followed the c3 photosynthetic pathway however the 13cplant values of different species formed two distinct isotopic groups this can be best explained by different water use efficiencies with arid adapted species having significantly more positive 13cplant values than less water efficient species the ranges and means of 13cbody and 13cplant were statistically indistinguishable from one another suggesting that 13cbody was primarily a function of local vegetation composition h melanostoma 13cshell reflected the 13cplant of local vegetation with a positive offset between body diet and shell of 14 5 1 4 therefore in the gebel al akhdar where only c3 plants are present higher mean 13cshell values likely reflect greater abundances of water efficient c3 plants in the snails diet and therefore in the landscape whilst lower mean 13cshell values likely reflect the consumption of less water efficient c3 plants the distribution of these plants is in turn affected by environmental factors such as rainfall these findings can be applied to archaeological and geological shell deposits to reconstruct late pleistocene to holocene vegetation change in the southeast mediterranean

geotechnical assessment and engineering classification of the antalya tufa rock southern turkey abstract this study mineralogically and geotechnically assesses the antalya tufa rock types which are highly variable in nature geological observations geotechnical site investigations and in situ and laboratory tests have been performed to determine the parameters i e organic matter content rock fabric apparent porosity unit weight uniaxial compressive strength young s modulus tensile strength cohesion and angle of internal friction that may have a significant influence on tufa rock behavior and to develop a comprehensive geotechnical database for the antalya tufa rock the geotechnical database was utilized for the engineering classification of the antalya tufa rocks using the gsi classification system

empirical correlations of shear wave velocity vs and penetration resistance spt n for different soils in an earthquake prone area erbaa turkey abstract the seismicity of the northern part of turkey is mainly controlled by the north anatolian fault zone nafz the nafz is one of the world s most active seismic zones and has produced destructive earthquakes and related hazards in the northern region of turkey several earthquakes and earthquake related hazards have occurred along different segments of this fault zone in the recent past the study area erbaa town is located along the eastern segment of north anatolian fault zone nafz and is one of the largest towns of tokat province in the middle black sea region of turkey the center of erbaa is located on the left embankment of the kelkit river after the disastrous 1942 ms 7 2 and 1943 ms 7 6 earthquakes the settlement was shifted southwards as a part of a seismic microzonation study of the erbaa area shear wave velocity vs values of the geological units exposed in this area were required for site response analyses the geological units in the study area consist mainly of alluvial and pliocene units these layers were evaluated on the basis of drilling in situ spt scptu and spt based uphole and laboratory testing in this study empirical correlations between shear wave velocity vs and standard penetration test blow counts spt n were considered in order to define shear wave velocity profiles for the study area the relationships between shear wave velocity standard penetration test spt blow counts and the soil properties were evaluated as functions of depth spt based uphole tests were performed to measure shear wave velocity during drilling operations in some of the borings the spt based vs values were computed with different empirical formulas and compared with the measured spt based uphole vs measurements the empirical correlations were found to require modification to provide the best correlation for this site the depth factor was considered during the development of new empirical equations therefore a site specific formula was proposed in order to obtain vs profiles for all layers in the study area

behavior of a 31m high excavation supported by anchoring and nailing in residual soil of gneiss abstract a 31 m high excavation located at niteroi rj in residual soil from gneissmigmatite with high nspt 40 was performed for a building construction two levels of anchored walls were considered in order to guarantee stability when the construction of the upper wall was almost completed a crack parallel to the direction of the wall formed in the hilltop it was decided that the construction works would cease in order to perform additional studies the presence of reasonably continuous soil layers of different colors gray white and red with thicknesses varying from a few millimeters to some centimeters clearly observed in the face of the cut slope the inclination of these soil layers varied along the length of the excavation and they were in an orientation that was unfavorable for the stability of the cut laboratory tests were performed and the presence of high activity clay mineral and low shear resistance parameters was determined for the gray clayey sand soil those weakness planes i e the thin layers of gray clayey sand had not been properly detected in the previous studies that supported the design of those walls considering these new findings the original project was reviewed and it was decided that soil nailing would be used for accomplish the excavation to the original planned level the upper wall was also reinforced with additional anchors load measurements in the nails indicated that the stress state in the soil mass corresponded to the active condition at the final level of excavation significant lateral movements were measured and varied according to the direction and inclination of the cited weakness planes it was observed that the reliquiae planes were fundamentally important to the behavior of the excavation

the role of porosity on the engineering geological properties of 1669 lavas from mount etna abstract a comprehensive laboratory characterization of volcanic rocks belonging to the 1669 lava flow of mount etna recognized as one of the largest and most catastrophic event ever occurred is presented herein with the aim of investigating on their peculiar mechanical attitude the multi disciplinary approach proposed herein pointed out that although originated by the same eruptive event 1669 trachybasaltic lavas are characterized by relevant differences in porosity and rock fabric from both the qualitative and quantitative points of view this is an interesting aspect because such rocks are quarried for the production of high quality material to be employed for engineering geological purposes even in the val di noto unesco world heritage site in this perspective their detailed characterization is an essential practice even preparatory for the engineering geological use to this purpose this paper provides a focus on the laboratory investigation of these rocks which according to three different porosity classes underwent petrographic physical mechanical and seismic analyses interesting statistical correlations allowed understanding the mutual dependence of the main engineering geological parameters highlighting how porosity through both vesicles and microcracks plays a leading role from the engineering geological point of view achieved results provide a scientific casuistry on this topic and are a reliable reference for studies on similar rock types worldwide since lavas are among the most used rock materials in the engineering geological practice

holocene paleoenvironment 7200 4000 cal bp of the los castillejos archaeological site se spain inferred from the stable isotopes of land snail shells abstract neolithic copper age and modern land snail shells from the los castillejos archeological site 37 20 n se iberian peninsula were analyzed for 13 c 12 c and 18 o 16 o ratios to estimate the paleoenvironmental conditions during shell deposition modern and ancient 13 c values ranged from 9 2 to 7 7 and from 13 6 to 5 7 respectively and they differed among taxa 13 c values were similar for neolithic 13 c 8 1 2 3 copper age 13 c 8 4 0 6 and modern 13 c 8 4 0 5 herbivorous cernuella specimens alternatively fossil shells of the herbivorous ferussacia folliculum 13 c 9 9 1 2 and the omnivorous rumina decollata 13 c 11 1 2 showed substantially lower 13 c values than modern specimens which may suggest lower water stress during the early to mid holocene than today the 18 o values from modern specimens ranged from 1 1 to 0 6 while the 18 o values from fossil specimens ranged from 6 7 to 0 and they differed among species cernuella exhibited shell 18 o values that increased from the neolithic 18 o 2 3 1 8 and copper age 18 o 1 7 0 6 to the present 18 o 0 3 0 5 the 18 o values of fossil shells of f folliculum 18 o 3 7 1 0 and r decollata 18 o 4 0 1 6 were also lower than modern shells calculations of a published snail flux balance mixing model for 18 o values indicate that early to mid holocene shells precipitated during times when relative humidity was greater than today the se iberian peninsula was noticeably wetter 7200 cal bp and experienced drier conditions thereafter the results are consistent with other regional paleoclimatic proxies and reinforce the potential use of land snail shells as paleoenvironmental archives

the loess deposits of buca dei corvi section central italy revisited loess deposits have been described in the past for the upper section of buca dei corvi succession central italy in this paper the deposits were re analysed to clarify the depositional environment and to attempt a paleoclimate reconstruction two radiocarbon dates on pedogenic carbonate constrain the ages to the late glacial and are consistent with previous osl dating of the top of the succession the non marine mollusc assemblage shows typical character of cold and dry climatic conditions testified by strong oligotypical composition mineralogy and geochemistry of the sediments indicate the abundant presence of exotic quartz mineral which can be explained only by wind transport probably wind transport was also responsible of deposition of carbonate which then dissolved and re precipitated producing pedogenic concretions stable isotopes 13c 12c and 18o 16o ratios of the concretions are consistent with a climate drier than present conditions with an environment characterized by sparse vegetation

clumped and stable isotopes of land snail shells on the chinese loess plateau and their climatic implications abstract we report stable 13cshell 18oshell and clumped isotope 47 compositions of modern and last glacial fossil snail shell carbonates from the luochuan and weinan sections on the central and southern chinese loess plateau clp our study reveals that the average 47 temperature t47 of modern snails is consistent with monitored temperatures during the snail growing season at the studied locations and is 10 c higher than that of fossil snails from glacial time moreover the average 13cshell of modern snails is more depleted than that of fossils we argue that the 13cshell cannot record changes in plant communities i e the c3 c4 ratio on the clp and may mainly indicate arid conditions with depleted values reflecting reduced aridity additionally the reconstructed snail body water 18o 18owater of modern snails is more enriched than 18o in modern growing season precipitation and 18owater of fossils this contrast may be related to the high degree of evaporative enrichment of environmental water 18o in the body ingested by modern snails under warm conditions therefore we suggest that using 18oshell to directly reconstruct the oxygen isotopes of precipitation is difficult and that higher 18oshell and 18owater values probably indicate higher environmental temperature stronger evaporative enrichment on glacial interglacial timescales on the clp

foundation evaluation of underground metro rail station using geophysical and geotechnical investigations abstract excavations for underground space developments in a thickly populated urban area are sometimes hindered by unexpected formidable consequences like formation of sinkholes or uneven settlement of foundations such troublesome incidences occasionally damage structures in the vicinity of excavations although adequate design guidelines and codes of practices are adopted the disturbance of subsurface regime due to excavation or construction activities often leads to undesired stability issues with resultant appearance of weak zones the reinforcement of weak zones by grouting is one of the common remedies without demarcating the weak or the affected zones becomes counter productive excavation at a location in chennai mega city for metro rail was severely affected by soil piping with development of sinkholes and weakening of the surrounding strata subsequently development of cracks in the adjacent buildings and caused tilting of the nearby taller structures the mandated the geophysical and geotechnical investigations were carried out to demarcate the affected area to avoid further deterioration of the site cross hole seismic p and s wave velocities were estimated between10 pairs of boreholes up to 20 m depth on both the sides of the excavation two electrical resistivity tomography ert profiles each of 141 m in length were carried out in the same location cross hole s wave velocity profiles and resistivity tomograms clearly indicate the presence of weak zones and possible sinkhole locations site specific empirical relationship was established between s wave velocity and standard penetration test spt n value this relationship was further used for determination of spt n values from the measured vs values to compare the subsurface conditions identified under pre and post excavations the results confirmed the presence of weak zones which are responsible for the weakening of the surrounding strata in the foundation geophysical and geotechnical investigations similar to present investigation can be useful for designing metro rail projects in a subsurface environment comprising alluvium sand clay mixed with silt pebbles and boulders lying near a region of ground water pocket in a thickly populated urban area

shear wave velocity as function of cone penetration test measurements in sand and silt mixtures abstract a database of research quality piezocone test cptu results and shear wave velocity v s measurements assembled in the context of an ambitious research project carried out at the treporti test site venice italy has been interpreted in order to study the seismic response of the predominantly silty sediments forming the venetian lagoon basin as well as to explore potential correlations for such intermediate soils the experience gained so far with the treporti database and other field data collected in the lagoon area has shown that the mechanical behavior of venetian soils cannot be easily interpreted using the existing and well established cptu based approaches hence the interest in examining whether or not the seismic response of these sediments expressed in terms of shear wave velocity follows the framework published for other soils the applicability to the available data of a number of existing correlations originally developed either for sands or fine sediments has been first investigated and updated relationships have been then suggested furthermore the small strain stiffness calculated from v s measurements has been compared with the field stiffness derived from the observed performance of a full scale test embankment built in the treporti site so as to verify common design assumptions the verification and calibration of existing approaches are likely to constitute a useful contribution to the practice of geotechnics not only in the venetian lagoon area but also in the silty deposits usually present in the surrounding alluvial plain and other similar depositional environments allowing rapid estimates of seismic soil classification as well as small strain stiffness properties for preliminary design or at sites where only cone penetration data are available

rapid least squares inversion of apparent resistivity pseudosections by a quasi newton method1 a fast inversion technique for the interpretation of data from resistivity tomography surveys has been developed for operation on a microcomputer this technique is based on the smoothness constrained least squares method and it produces a two dimensional subsurface model from the apparent resistivity pseudosection in the first iteration a homogeneous earth model is used as the starting model for which the apparent resistivity partial derivative values can be calculated analytically for subsequent iterations a quasi newton method is used to estimate the partial derivatives which reduces the computer time and memory space required by about eight and twelve times respectively compared to the conventional least squares method tests with a variety of computer models and data from field surveys show that this technique is insensitive to random noise and converges rapidly this technique takes about one minute to invert a single data set on an 80486dx microcomputer

reconstruction of late pleistocene climate in the valsequillo basin central mexico through isotopic analysis of terrestrial and freshwater snails we aim to reconstruct the climatic and environmental conditions in the valsequillo basin during the deposition of the valsequillo gravels between c 40 000 and 8000 years ago when large mega fauna and potentially humans occupied the basin fossil freshwater fossaria sp and sphaeriidae family and terrestrial polygyra couloni holospira sp and cerionidae family snail shells from sections within the barranca caulapan were collected for oxygen and carbon stable isotope analysis oxygen and carbon isotopes in terrestrial and freshwater snail shells relate to local climatic parameters and environmental conditions prevailing during the lifetime of the snail whole shell isotope analysis showed that c 35 000 years ago climate in the valsequillo basin was similar to the present day between c 35 000 and 20 000 bp conditions became increasingly dry after which conditions became wetter again although this record is truncated intra shell isotopic analyses show that the amount of precipitation varied seasonally during the late pleistocene if people did reach this part of the americas in the late pleistocene they would have experienced changing long term and seasonal climatic conditions and would have had to adapt their life strategies accordingly

holocene snail shell isotopic record of millennial scale hydrological conditions in western mediterranean data from bauma del serrat del pont ne iberian peninsula land snail shells are a common component in mediterranean holocene archaeological deposits providing the opportunity to explore their potential as source of information concerning human behaviour and palaeoclimatic conditions many well preserved shells of the caenogastropod pomatias elegans were recovered along the holocene succession of bauma del serrat del pont bsp in the iberian peninsula their oxygen 18os and carbon 13cs isotopic compositions were analysed and compared with that of modern shells of the same species collected in two distinct areas near the archaeological site modern shells from site a shady and b sunny show distinctly different oxygen isotopic ratios possibly due to the effect of microenvironmental conditions e g temperature and relative humidity carbon isotopes by contrast reveal similar values isotope mass balance suggests a prevalent contribution of vegetation 70 integrated with foreign carbonates 30 to 13cs of modern snails early late holocene shells 9 2 5 cal ka bp have lower 18os compared with modern counterparts which is consistent with prevailing wetter conditions compared with present day the 13cs reveals distinct hydrological regimes wet and dry conditions from early to late holocene respectively in general shell isotopic records from western and central mediterranean regions suggest wetter conditions during the middle holocene with a possible reduction in humidity from 4 cal ka bp the 18os indicates a possible latitudinal difference in hydrological balance between mediterranean and atlantic europe as inferred by previous studies of regional palaeoclimatic records carbon isotopes by contrast do not provide a clear climatic picture probably due to the effect of distinct vegetation structure and composition comparisons with other environmental archives reinforce the concept of regional shell oxygen isotopic response to millennial scale changes in hydrological condition over the western and central mediterranean during the late quaternary

implications of the apparent 14c age of cultured achatina fulica and the spatial features of 14c ages among modern land snail shells in china abstract it has long been known that many terrestrial snail shells are subject to the so called limestone effect however the magnitude and impact of this effect on the 13c values of snail shells and soft body tissue 13cshell and 13cbody are still unknown in this study achatina fulica snails were hatched and cultured under controlled conditions and supplied with 14c free calcium carbonate and lettuce a c3 plant as a calcium source and food supply respectively the snail shells and soft body tissues were sampled monthly for 5 months and 13c and radiocarbon dating analyses were conducted to trace carbon source variations at different growth stages our results show that the apparent 14c age of the shells and the corresponding 13cshell values increased progressively from the 1st to 3rd months and subsequently decreased during the 4th and 5th months the results demonstrate for the first time that carbonate ingestion has a straightforward influence on the 14c ages and 13c values of shells and that the limestone effect changes over the lifetime of snails moreover the apparent 14c ages of snails sampled in the field are older than modern ages when taken from the northern carbonate region and relatively young or the same as modern ages when collected from ferralic soils this further supports our findings from cultured snails and suggests that snail shells are good archives for radiocarbon dating purposes in southern china although the 13c values of the soft body tissues of cultured snails vary synchronously with those of the shell this seemingly common phenomenon cannot be easily explained by carbonate ingestion as the snail bodies are of more recent origin than the shells atmospheric co2 may be another candidate explaining the synchronicity between 13cshell and 13cbody as well as the f 14c variations of snail bodies however it is still unclear how snails differentially incorporate carbon from different sources e g carbonate and atmospheric co2 at different growth stages since carbon from different sources is combined in the bicarbonate pool in the hemolymph before being used by snails

integrated geophysical approach in assessing karst presence and sinkhole susceptibility along flood protection dykes of the loire river orleans france abstract non invasive geophysical methods are often used for detecting near surface defects and monitoring seepage in river dykes or dams between 2008 and 2009 a series of geophysical experiments was conducted to detect karst features below the dykes of the loire river orleans france multi channel analysis of seismic surface waves masw was used to obtain the shear wave velocity vs profile of the subsurface below the dykes as an effective approach to investigating the structure of the dykes multi channel resistivity surveys were also used to evaluate the electrical properties of material inside and under the dykes this study discusses the exploration strategy and results for several sections of the dyke system based on the experimental data vs contours are used to geometrically and qualitatively describe the subsurface under the dykes and identify areas of mechanical weakness corresponding to karst features while resistivity contours allow distinguishing interactions between the karst and the dykes through the identification of areas of downward material movement known and unknown anomalies are identified a practical approach that combines seismic and electric resistivity results is proposed to assess karst presence and sinkhole hazards along the investigated dykes using a susceptibility index referring to the likelihood level of the events as a validation method areas of strong karst susceptibility index along the dykes are compared to known collapse event sinkholes dyke breaches etc locations available in databases

enhanced rainfall in the western mediterranean during deposition of sapropel s1 stalagmite evidence from corchia cave central italy a stable isotope record from a stalagmite collected from antro del corchia cave apuan alps central italy supported by 17 uranium series ages indicates enhanced regional rainfall between ca 8 9 and 7 3 kyr cal bp at the time of sapropel s1 deposition within this phase the highest rainfall occurred between 7 9 and 7 4 kyr cal bp comparison with different marine and lake records and in particular with the soreq cave record israel suggests substantial in phase occurrence of enhanced rainfall between the western and eastern mediterranean basins there is no convincing evidence for major climatic change at the time of the 8 2 kyr event

identification and quantitative analysis of sinkhole contributing factors in florida s karst abstract sinkholes are one of the major geohazards in karst areas causing loss of life and significant economic loss as well sinkhole forming mechanism varies depending on the geological environment and florida s sinkholes are formed through the process of interaction between groundwater flow and cover soils the significance of this paper is 1 to identify key sinkhole contributing factors and 2 to quantify the impact of those factors on sinkhole formation particularly this study accounted for geomechanical factors that contribute to sinkhole raveling due to erosion and mechanical stability of overburden soils identification of key sinkhole contributing factors will allow developing a probabilistic sinkhole prediction model the study area was focused on east central florida where cover collapse sinkholes often occur uniform distribution transformation was employed for the quantitative analysis on each factor and then case studies with specific examples are then presented to validate the results of the quantitative analysis in conclusion the identified key factors are hydraulic head difference soil permeability thicknesses of aquifer systems and proximity to karst features e g existing sinkhole the critical permeability kcrit showing a rapid increase of sinkhole occurrence is about 20 cm h thickness and characteristics of cover soils seem a controlling factor of sinkhole types and the overburden thickness around 40 to 45 m tends to form the collapse type a multivariate regression analysis indicates that the thickness of the surficial aquifer system is the most significant factor and then the head difference and the proximity to karst features follow in order

the grain size depositional process in wetlands of the sanjiang plain and its links with the east asian monsoon variations during the holocene abstract compared to the well studied the grain size depositional process in hydraulic and aeolian sediments the process in wetlands is still poorly understood in this study the grain size components of a well dated mud peat profile sj2 in the sanjiang plain were partitioned using a lognormal distribution function the results suggest that the lacustrine deposits contain four distinct unimodal grain size distributions c 1 through c 4 with their modal sizes ranging 0 7 1 6 2 4 8 7 15 7 27 8 and 380 2 529 6 m respectively only the c 1 and c 3 were identified in the peat layers a grain size depositional modal was introduced to explain the environmental meanings of the four components c 3 as a nearshore suspension component was the most sensitive component to the variation of local hydraulic conditions based on the variation of c 3 percentages of the profile sj2 the local hydraulic conditions were tentatively reconstructed and the results showed a close relation with the monsoon variations during the holocene accordingly we suggest the relative coarse component of the polymodal peat deposits in monsoonal regions can be used as a sensitive indicator for the hydraulic conditions and the monsoon circulations in the geological past

three dimensional site characterization with borehole data a case study of suzhou area abstract due to the inherent spatial variation of the site information and the limited number of boreholes which could be afforded in a specified project the geotechnical and geological information at a site could not be fully characterized which imposes a significant challenge to the analysis design and construction of the geotechnical system of concern indeed the issue of site characterization has long puzzled engineers this paper presents a three dimensional site characterization in the urban area of suzhou where plenty of borehole explorations have been undertaken with the borehole database established the relationship between the shear wave velocity and the depth is analyzed this relationship can be captured by regression based models and then a sequence extrapolation method that is based upon the linear relationship between the time average shear wave velocities is developed for the prediction of the shear wave velocity along the depth next a three dimensional characterization and visualization of the stratigraphic model in the urban area of suzhou are presented the characterization of the stratigraphic model in this paper is realized through the characterization of the elevations of the interfaces between adjacent strata in the sequence stratigraphic structure the sequence stratigraphic structure is derived with a method that is based upon the one by one comparison and updating of the borehole data and then the best unbiased estimator of the elevations of the interfaces between adjacent strata at the concerned site is predicted with the kriging based interpolation method with the aid of arcgis engine a three dimensional visualization of the characterized stratigraphic model is made possible

seismic tomography imaging of an unstable embankment abstract seismic tomography imaging was employed to make a diagnosis and choose a remedy for an embankment supported by a retaining wall showing clear evidence of structural instability the geometry and structural characteristics of the wall the inside geometry of cracks and the physical parameters of the underground materials were the primary objectives of the geophysical survey seismic data were acquired along two vertical sections each one delimited by the lines of the sources within an inclined borehole and of the receivers lying on the ground for each section a total of 744 travel times were inverted to obtain compressional wave velocities on a regular rectangular grid of squared cells 1 m 1 m using an inversion algorithm which is based on the simultaneous iterative reconstruction technique sirt ultrasonic tests carried out in laboratory on intact specimens together with other supplemental site information improved tomography resolution allowing global and node constraints that forced the solution of the inverse problem to match known boundary values tomography imaged two high velocity zones separated by a curved shape low velocity zone the first ones were found to be compatible with the concrete retaining wall and with the schist materials ranging from highly weathered to intact schist while the low velocity zone was interpreted as filling materials and or completely decomposed rock schist the combination of seismic tomography and laboratory measurements allowed extrapolation of important parameters over a large volume of rock mass otherwise only representative of small rock samples near boreholes it also enabled engineering characterization of subsurface rock mass providing useful and accurate information to design a remedy for the embankment

application of cross hole seismic measurements in site investigation surveys application of the cross hole seismic method to site investigation surveys for civil engineering developments is illustrated by case histories from the united kingdom using the borehole sparker probe developed in mccann et al 1975 as the seismic source at newborough anglesey it is shown that this source generates both a compressional wave and a vertically polarized shear wave in the borehole the measured velocity values are used to determine the dynamic elastic moduli of the saturated sand deposit at this site at cocking sussex and east fleet dorset the presence of an air filled void between two boreholes is shown to have a significant effect on the velocity of propagation and amplitude of the transmitted seismic signals this work is extended at maidstone kent where the technique is used to confirm the presence of a cavity below the foundation of a house in the hot dry rock geothermal project at rosemanowes cornwall increased fracturing of the granitic rock mass following explosive stimul

early middle holocene land snail shell stable isotope record from grotta di latronico 3 southern italy this paper compares stable isotope d 18 o and d 13 c records of early middle holocene land snail shells from the archaeological deposits of grotta di latronico 3 ltr3 southern italy with modern shell isotopic data no substantial interspecific variability was observed in shell d 18 o d 18 os of modern specimens pomatias elegans cornu aspersum eobania vermiculata helix ligata and marmorana fuscolabiata in contrast interspecific shell d 13 c d 13 cs variability was significant probably due to different feeding behaviour among species the d 18 os values of living land snails suggest that species hibernate for a long period during colder months so that the signal of 18 o depleted winter rainfall in their d 18 os is lost this suggests that d 18 os and d 13 cs values of pomatias elegans from this archaeological succession provide valuable clues for seasonal spring autumn climatic con ditions during the early middle holocene the d 18 os values of fossil specimens are significantly lower than in modern shells and in agreement with other palaeoclimatic records suggesting a substantial increase of precipitation and or persistent changes in air mass source trajectories over this region between ca 8 8 cal ka bp and 6 2 6 7 ka ago the d 13 cs trend suggests a transition from a slightly 13 c enriched to a 13 c depleted diet between early and middle holocene compared to present conditions we postulate that this d 13 cs trend might reflect changes in the c3 vegetation community potentially combined with other environmental factors such as regional moisture increase and the progressive decrease of atmospheric co2 concentration copyright 2010 john wiley sons ltd

oxygen and carbon stable isotopes of modern land snail shells as environmental indicators from a low latitude oceanic island abstract land snails provide a unique opportunity to study terrestrial paleoenvironments because their shells which are generally highly abundant and well preserved in the fossil record contain a temporal record of environmental change in the form of isotope codes to evaluate the utility of this approach for a low latitude oceanic setting 207 modern shells of 18 species of land snail were analyzed for their oxygen and carbon isotope composition along a north and south facing altitudinal gradient 10 2160 m a s l in tenerife island 28 n of the canary archipelago shells collected at each locality showed a relatively large range in isotope composition which was greater along the south facing transect drier and hotter suggesting that the variance in shell isotope values may be related to water stress although pooled isotope values did not generally show strong relationships with environmental variables i e altitude temperature and precipitation mean isotope values were strongly associated with some climatic factors when grouped by site the mean 18o value of the shell 18oshell by site displayed a negative correlation with elevation which is consistent with the positive relationship observed between temperature and the 18o value of rain 18orain calculated 18o values of the snail body water 18obody derived from observed temperatures and 18oshell values using the equation of grossman and ku grossman e l and ku t l 1986 oxygen and carbon isotope fractionation in biogenic aragonite chem geol isotope geosci sec 59 59 74 displayed a trend with respect to altitude that was similar to measured and hypothetical 18o values for local rain water the calculated 18obody values from the shell declined 0 17 vsmow per 100 m which is consistent with the altitude effect observed for tropical rains in western africa and it correlated negatively with rainfall amount accordingly lower 18oshell values indicate lower temperatures lower 18orain values and possibly higher rainfall totals a positive correlation between the mean 13c values of shells 13cshell and plants by site suggests that shells potentially record information about the surrounding vegetation the 13cshell values varied between 15 7 and 0 6 vpdb indicating that snails consumed c3 and c4 cam plants where more negative 13cshell values probably reflects the preferential consumption of c3 plants which are favored under wetter conditions individuals with more positive 13cshell values consumed a larger percentage of c4 plants other potential factors such as carbonate ingestion or atmospheric co2 contribution were unlikely that were more common at lower elevations of the hotter and drier south facing transect the relatively wide range of shell isotope values within a single site requires the analysis of numerous shells for meaningful paleoclimatic studies although small differences were observed in isotope composition among snail species collected at a single sampling site they were not significant suggesting that isotope signatures extracted from multi taxa snail data sets may be used to infer environmental conditions over a broad range of habitats

stable isotope record in mollusca and pedogenic carbonate from late pliocene soils of central italy abstract the late pliocene younger than 2 5 ma alluvial fan succession of toppetti quarry near todi umbria central italy includes many palaeosols pedogenic carbonate concretions and mollusc remains were separated from 73 palaeosols collected along 150 m of exposure and analysed for their oxygen and carbon stable isotope content 13c and 18o of the pedogenic carbonate and land snail shells suggest that no dramatic change in local climate took place values of the pedogenic carbonates are similar to other data reported for the mediterranean region 18o data suggest a mean annual temperature and or 18o similar to modern climatic conditions carbon isotope data from both land snails and pedogenic carbonate are consistent with a prevailing type c3 vegetation a mixture of forest and c3 grassland sustained by a mean annual precipitation between 300 and 1000 mm mainly in the cool periods of the year seems to be the most likely scenario the limited variation shown by the isotope composition of the biogenic and inorganically precipitated carbonate indicates that the environmental variations are referable mainly to change of humidity rather than temperature

designing foundations around sinkholes there is an increasing awareness among developers and owners of the need to conduct subsurface exploration studies before planning a project the use of geophysical methods in subsurface exploration has been established to be valuable in locating sinkhole activity and suggesting pro active measures however the value of geophysical exploration to supplement geotechnical investigation has not yet been stressed primarily out of cost concerns ground penetrating radar and electrical resistivity tests which were used to determine void spaces below proposed buildings are gaining wider acceptance as a result of information obtained from geophysical tests foundation designs were modified to use post tensioned mats or to include grouting an improved grouting technique that controls the volume of grout being pumped is also discussed this paper is an attempt to document some case studies which resulted in making design improvements to mitigate the effects of known sub surface solution activity these case studies illustrate the use of geophysical exploration methods in adding value to the engineered design

oxygen and carbon isotopic composition of modern terrestrial gastropod shells from lipari island aeolian archipelago sicily abstract oxygen 18os and stable carbon 13cs isotopic compositions of modern terrestrial gastropod shells from lipari island in the aeolian archipelago sicily have been analysed and compared with local meteoric water 18o 18op and vegetation 13c 13cv respectively results reveal that the 18os 18op relationship over the study area differs from those obtained on continental europe and italian shells implying that even at the scale of the mediterranean basin different relationships may co exist these differences have been interpreted as the increasing influence of mediterranean vapour water on tyrrhenian coasts at relatively low altitude up to 600 m asl which compensates for the effect of the 18op and possibly of temperature on shell 18o the steady state flux balance model fbm in agreement with previous studies suggests that snails are active prevalently at night shell carbon isotope ratios reflect the 13cv as predicted by the metabolic model and represent a valuable tool for identifying c3 plants with very distinct isotopic signatures

a late pleistocene refugium in mediterranean north africa palaeoenvironmental reconstruction from stable isotope analyses of land snail shells haua fteah libya abstract the late pleistocene to holocene archaeological record of north africa is key to understanding the emergence of anatomically modern humans into west asia and europe and the broadening of subsistence strategies in the shift from hunter gatherer to pastoral agricultural lifeways some contend that these developments were modulated by major shifts in climate and environment evaluation of this hypothesis requires the pairing of local and regional climate records with well dated archaeological sequences the haua fteah archaeological site in the gebel akhdar region of libya provides a key site to test this hypothesis as the cave contains one of the longest and most complete sequences of human occupation in north africa as well as abundant material for palaeoenvironmental reconstruction this study uses stable isotope analyses 18o and 13c of the terrestrial mollusc helix melanostoma to construct a palaeoenvironmental framework for interpreting north african human environment interactions from the upper palaeolithic to the neolithic 30 000 to 5000 years ago the land snail stable isotope records from haua fteah suggests that cool arid conditions in the cave peaked during marine isotope stage mis 2 this stage was however only marginally drier than previous and subsequent stages and coincided with an increase in occupation density in the cave this suggests that the gebel akhdar may have served as an environmental refugium from the more extreme aridity in the surrounding sahara and arid coastal plains for late stone age lsa populations in north africa conditions became progressively wetter towards the holocene however generally wetter conditions were interrupted by two arid episodes at c 8 0 ka and 7 3 ka that appear to coincide with regional changes reflected elsewhere in the mediterranean basin

implications for late holocene climate from stable carbon and oxygen isotopic variability in soil and land snail shells from archaeological site 41km69 in texas usa abstract well preserved fossil land snail shell collected in a 115 cm soil profile from archaeological site 41km69 in texas usa minimally span the past 2200 years and provide an opportunity to explore the paleoclimate implications of isotopic variability in shell carbonates bulk soil carbonates and soil organic matter carbon isotopic compositions 13 c values of modern and archaeological adult snail shell carbonates suggest significant 60 dietary input of c 3 plants during all periods oxygen isotopic compositions of shells suggest that the isotopic composition of environmental water available at the time of shell growth has changed little over the period of the profile a linearly decreasing trend in 13 c of soil organic matter from 22 8 at the bottom of the profile 115 cm below surface to 25 6 for modern surface samples indicate an overall 20 increase in abundance of c 3 plants this implies a progressively wetter climate and less severe water stress conditions or decreasing summer rainfall that is in agreement with other studies on late holocene climate change in the southern great plains usa these results strongly suggest a stable climate that favored c 3 vegetation in this portion of texas during this period

equilibrated clumped isotope signatures of land snail shells observed from laboratory culturing experiments and its environmental implications abstract this study reports on the clumped isotope values 47 of land snail shells precipitated at known temperatures ranging from 20 c to 30 c our observed shell 47 values fall into the uncertainties of published 47 t calibration line e g kelson et al 2017 indicating the shell aragonite of land snails is precipitated at clumped isotopic equilibrium without an obvious 47 vital effect the 47 data are neither related to the various bulk isotopic input sources both for 13c and 18o which result from differences in the supplied food and water nor are they related to the ingested carbonate composition or snail growth rate furthermore we preliminarily applied the 47 t calibration kelson et al 2017 to calculate the mean growth temperatures of the parent snails results suggest that the clumped isotope values for land snail shells can be regarded as a useful tool to reconstruct the mean seasonal temperature of snail activity when the environmental parameters are optimum future studies should focus on the applicability of this relationship to snails in natural environments where the self preservation or acclimatization mechanisms are more complex

crosshole seismic testing procedures and pitfalls crosshole seismic testing is a valuable technique for determining seismic velocity profiles for critical structure siting investigations improper field procedures however can result in the acceptance of apparent velocities as true velocities leading to unconservative design values common pitfalls in crosshole seismic testing are 1 the use of source receiver borehole spacings too large to enable the determination of true formation velocities 2 the use of in hole station spacings too large to allow resolution of thin velocity layers of interest 3 the use of incremental traveltimes between widely spaced receiver boreholes and 4 the naive assumption that boreholes are vertical and hence parallel a procedure is presented whereby field programs can be more rationally planned

stable carbon and oxygen isotopic variations in modern rabdotus land snail shells in the southern great plains usa and their relation to environment abstract variations of stable isotopic ratios of carbon 13c 12c and oxygen 18o 16o were investigated in modern shells of two species of rabdotus land snails r dealbatus and r alternatus in the southern great plains geographic variation in relation to climate and vegetation microgeographic variation variability among individuals and detailed records of seasonal variations within individual shells were studied stable carbon isotopic ratios in shell carbonate are primarily a function of the isotopic composition of the diet of the snails as represented by the isotopic composition of shell organic matter this in turn reflects the presence or absence of cam crassulacean acid metabolism or c4 plants vegetation density may have a small effect on the carbon isotope ratios microgeographic variation samples within 25 to 300 m is greater than that seen across different climatic regions and points to very local control of isotopic variations predominantly related to vegetation seasonal variations as assessed through serial analysis of individual shells up to 35 samples per shell may provide a means for distinguishing between isotopic influences of perennial cam vs annual c4 plants carbon isotopic variations in time series of shells from a site provide a means of reconstructing temporal changes in environment and climate oxygen isotopic values of shell carbonate are uniform across the region and also show no significant microgeographic variation the oxygen isotopic composition appears to be mainly a function of the rainwater isotopic composition with no direct influence of rainfall amount or evaporative effects the 18o values are only 2 enriched relative to estimated equilibrium with rainwater variability is low sd of 0 8 among sites so the isotopic composition of fossil rabdotus shells can provide a precise record of changes in the isotopic composition of rain over time

environmental significance of 13c 12c and 18o 16o ratios of modern land snail shells from the southern great plains of north america c 12 c and 18 o 16 o ratios of aragonite shells of modern land snails from the southern great plains of north america were measured for samples from twelve localities in a narrow east west corridor that extended from the flint hills in north central oklahoma to the foothills of the sangre de cristo mountains in northern new mexico usa across the study area shell y 18 o values pdb scale ranged from 4 1x to 1 2x while y 13 c values ranged from 13 2x to 0 0x y 18 o values of the shell aragonite were predicted with a published steady state evaporative flux balance model the predicted values differed with one exception by less than 1x from locality averages of measured y 18 o values this similarity suggests that relative humidity at the time of snail activity is an important control on the y 18 o values of the aragonite and emphasizes the seasonal nature of the climatic information preserved in the shells correlated y 13 c values of coexisting vallonia and gastrocopta suggest similar feeding habits and imply that these genera can provide information on variations in southern great plains plant ecology although there is considerable scatter multispecies transect average y 13 c values of the modern aragonite shells are related to variations in the type of photosynthesis i e c3 c 4 in the local plant communities the results of this study emphasize the desirability of obtaining isotope ratios representing averages of many shells in a locale to reduce possible biases associated with local variations among individuals species etc and thus better represent the bneighborhoodq scale temporal and or spatial environmental variations of interest in studies of modern and ancient systems d 2004 university of washington all rights reserved

investigating the potential and mechanism of soil piping causing water level drops in mountain lake giles county virginia abstract mountain lake located in giles county southwestern virginia is one of only two natural lakes in the state of virginia the lake exhibits rare self draining behavior with recent episodes in 2008 2011 and 2012 that drained the lake almost completely and revealed the presence of four sinkhole like depressions with piping holes at their bottoms and sides near the northeastern and northwestern margins of the lake this phenomenon has raised concern over declining tourism to the mountain lake lodge the purpose of this study was to investigate the piping potential of lake bottom sediment and its role in seepage and lake level fluctuations sixteen grab samples of lake bottom sediment were collected from the vicinity of the depressions additionally five shelby tube samples were obtained to determine the in situ density of the sediment grain size distribution atterberg limits and compaction mold permeameter tests were used to evaluate lake sediment s susceptibility to piping grain size distribution and atterberg limits test results reveal that the lake bottom sediment consists predominantly of fine sand and silt which are well known for their susceptibility to piping results of the compaction mold permeameter test show that the critical hydraulic gradient ic the hydraulic gradient at which the sediment starts to pipe ranges between 1 and 10 depending on the density grain size distribution and plasticity characteristics of the sediment these results suggest that piping of lake sediment is the primary mechanism responsible for the formation of lake bed depressions and lake level fluctuations

stable carbon and oxygen isotopic composition of modern land snails along a precipitation gradient in the mid latitude east asian monsoon region of china abstract the stable oxygen and carbon isotope composition 18oshell and 13cshell of land snail shells preserved in chinese eolian loess deposits have the potential to reconstruct past changes in the east asian summer monsoon easm since the late oligocene to assess the potential of 18oshell and 13cshell for the semi quantitative reconstruction of past variations of the easm we studied modern snails and the corresponding vegetation composition of three distinct ecosystems woodland grassland and mountains spanning a large rainfall gradient 178 1403 mm in the mid latitude east asian monsoon region the results show that different snail species in the three ecosystems have significantly different values of 18oshell and 13cshell the snails in woodland from the eastern plain area have significantly lower 18oshell and 13cshell values than those of snails in grassland from the chinese loess plateau and the snails from the qinba mountains region have values intermediate between the two systematic variations of the 13c of snail shells body tissues and local plants are evident along the rainfall gradient indicating that 13cshell is mainly influenced by the 13c of ingested plants which is controlled by the easm we confirm that 13cshell is a reliable precipitation proxy and we obtained a new empirical equation 13cshell 0 0030 0 0003 map 8 80 0 32 r 0 76 n 74 p

a high frequency sparker source for the borehole environment for tomographic investigations of shallow subsurface features of limited lateral extent a high frequency low cost borehole seismic source would be highly desirable particularly for investigators with limited budgets we constructed a simple arc discharge seismic source from off the shelf items this source consists of a salt water filled bottle containing exposed conductors of a coaxial cable across which 100 to 300 joules of electrical power were discharged this source produced a seismic pulse with a dominant frequency in the neighborhood of 1 5 khz and a half power bandwidth in excess of 1 khz repeatability of seismic signatures in a variety of environmental settings was excellent sufficient power was generated to observe seismic signals with at least a 35 db signal to noise ratio at horizontal borehole separations of 100 m for a borehole separation of 33 2 m signals with at least a 35 db signal to noise ratio were observed at angular ranges in the vertical plane to 68 degrees the hydrostatic

isotopic composition of precipitation in italy a first overall map abstract composite monthly samples of atmospheric precipitation were collected over different periods of time ranging from one to seven years at 77 different locations throughout italy these samples were measured for their oxygen and hydrogen isotopic composition to obtain basic information for hydrological and meteorological studies in this area on the basis of the results obtained a first map of the isotopic composition of precipitations in italy has been drawn up the main features of this map are the following 1 no isotopic latitudinal gradient has been found along the tyrrhenian coast from sicily to the italian french border despite the considerable range of latitude 2 a minor latitudinal gradient is found in the southeasternmost section of the country apulia partially favored by the local morphology 3 a marked shadow effect of the apennines is apparent along the southern section of the po valley and along the central section of the adriatic coast 4 the contribution of water vapor from the northernmost section of the adriatic sea affects the eastern and central sections of the po plain 5 the shadow effect of the alps is considerably smaller than expected 6 the isotopic vertical gradients calculated in nine different areas and based on groups of two to five different stations vary but are essentially close to about 0 2 100 m 7 when mean monthly temperature values were available their relationship with the isotopic composition of precipitation was found to be on average very poor 8 the relationship between mean 18o and mean d calculated for the collection locations shows shifts of both the slope and the deuterium excess when compared to the global meteoric water line these shifts are different for northern central and southern italy 9 in a few cases anomalously low monthly values suggest the existence of pronounced amount effects

grain size distribution function of polymodal sediments in hydraulic and aeolian environments and numerical partitioning of the sedimentary components most continental sediments are polymodal composed of overlapping components of which the grain size generally obeys some type of natural distribution the grain size components and their function types can be determined from frequency and cumulative curve plots in order to define the function formula of the grain size distribution the function parameters can be estimated by fitting a defined function formula to the measured grain size data of the sample which simultaneously achieves numerical partitioning of the sedimentary components genetic analysis of grain size components of hydraulic and aeolian sediments demonstrates the following environmental implications fluvial sediment is composed of isolated saltation and suspension components the sediments in closed lake basins are dominated by a suspension silt clay component with a small proportion of saltation sand the fine sand component makes up the majority of desert sand overlapping with a small proportion of fine dust aeolian loess is composed of two overlapping components a short suspension time silt component and a long suspension time fine component aeolian material in the north pacific deep sea sediments is dominated by long suspension time fine dust the fine component in aeolian sediments shows a consistent grain size distribution and genetic connection from the desert sand loess of northern china to the north pacific ocean which is mainly transported by westerly winds and is dispersed in the atmosphere forming a background dust c 2002 elsevier science b v all rights reserved

deciphering late quaternary land snail shell δ18o and δ13c from franchthi cave argolid greece this paper investigates the stable isotopic composition from late pleistocene holocene 13 to 10 5 cal ka bp shells of the land snail helix figulina from franchthi cave greece it explores the palaeoclimatic and palaeoenvironmental implications of the isotope palaeoecology of archaeological shells at the time of human occupation of the cave modern shells from around the cave were also analysed and their isotopic signatures compared with those of the archaeological shells the carbon isotope composition of modern shells depicts the consumption of c3 vegetation shell oxygen isotopic values are consistent with other mediterranean snail shells from coastal areas combining empirical linear regression and an evaporative model the 18os suggest that modern snails in the study area are active during periods of higher relative humidity and lower rainfall 18o probably at night late glacial and early holocene 18os show lower values compared to modern ones early holocene 18os values likely track enhanced moisture and isotopic changes in the precipitation source by contrast lower late glacial 18o could reflect lower temperatures and 18op compared to the present day shell carbon isotope values indicate the presence of c3 vegetation as main source of carbon to late glacial and early holocene snails