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

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

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

calibration of the stable isotope composition and body size of the arid dwelling land snail sphincterochila candidissima a climatic archive abundant in mediterranean archaeological deposits land snails recovered from archeological deposits may be used to deduce climatic conditions during prehistoric occupation because their aragonitic skeletons are usually well preserved and document valuable climatic information in the form of isotope codes since the snail sphincterochila candidissima is common in archeological sites along the western mediterranean but has been minimally investigated the present work examines the relationship between the oxygen 18o and carbon 13c stable isotopes of modern specimens and relevant meteorological data individuals of sphincterochila were regularly live collected throughout 1 year from september 2013 to october 2014 in tarragona ne spain and the 18o and 13c values were measured at the shell lip or aperture which depicts the last growth episode closest to specimens collection date shell margin 18o values varied from 3 1 in september to 0 8 in april average shell margin 18o values per collection date positively correlated with monthly avera

controls on morphological variability and role of stream power distribution pattern yamuna river western india abstract understanding the controls on the morphological variability of river systems constitutes one of the fundamental questions in geomorphic investigation channel morphology is an important indicator of river processes and is of significance for mapping the hydrology ecologic connectivity in a river system and for predicting the future trajectory of river health in response to external forcings this paper documents the spatial morphological variability and its natural and anthropogenic controls for the yamuna river a major tributary of the ganga river india the yamuna river runs through a major urban centre i e delhi national capital region the yamuna river was divided into eight geomorphically distinct reaches on the basis of the assemblages of geomorphic units and the association of landscape valley and floodplain settings the morphological variability was analysed through stream power distribution and sediment load data at various stations stream power distribution of the yamuna river basin is characterised by a non linear pattern that was used to distinguish a high energy natural upstream reaches b anthropogenically altered low energy middle stream reaches and c rejuvenated downstream reaches again with higher stream power the relationship between stream power and channel morphology in these reaches was integrated with sediment load data to define the maximum flow efficiency mfe as the threshold for geomorphic transition this analysis supports the continuity of river processes and the significance of a holistic basin scale approach rather than isolated local scale analysis in river studies

near surface k feldspar precipitation in cretaceous sandstones from the potiguar basin northeastern brazil abstract the cretaceous fluvial sandstones of the acu formation potiguar basin northeastern brazil contain abundant very early authigenic k feldspar overgrowths around detrital orthoclase and microcline grains detailed optical and cathodoluminescence petrography scanning electron microscopy and electron microprobe analyses provided information about the conditions and timing of precipitation of these overgrowths as well as of the associated diagenetic phases the overgrowths are optically discontinuous with the detrital grains untwined nonluminescing and were formed clear on grain surfaces under phreatic conditions the overgrowths commonly show a rhombohedral sanidine habit range in thickness from about 0 4 to 1 0 mm are chemically pure kalsi3o8 and constitute up to 6 of the whole rock the extremely early origin of the k feldspar overgrowths is indicated by their coating of mechanically infiltrated smectitic clays authigenic smectite rims booklet and vermicular aggregates of kaolinit

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

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

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

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

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

stable isotope composition of late glacial land snail shells from grotta del romito southern italy palaeoclimatic implications abstract stable isotope composition of living and fossil land snail shells was determined at grotta del romito southern italy with the aim to reconstruct environmental and climatic variation in the area during late upper palaeolithic the investigated succession comprised 15 different excavated layers spanning between ca 13 000 and 14 500 yr cal bp the oxygen isotope composition of snail shells indicates a marked decrease at the layer d8 suggesting a climatic deterioration consistent with the gi 1d climatic event older dryas this climate deterioration may have been related to a substantial decrease of mean annual temperature with associated changes in the regional atmospheric circulation however the environmental conditions at the time of shell s growth in the other intervals sampled suggest condition comparable to the present day the carbon isotope composition of fossil snail shells is in agreement with other records which indicate a general increase of the 13 c values of organic matter during pleniglacial to late glacial caused by substantially lower atmospheric co 2 concentration at that time

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

paleoenvironment of the folsom archaeological site new mexico usa approximately 10 500 14c yr b p as inferred from the stable isotope composition of fossil land snail shells abstract well preserved aragonitic land snail shells vallonia from late pleistocene eolian sediment in the folsom archaeological site in new mexico exhibit an overall decrease of 18opdb from maximum values of 2 7 more positive than modern to younger samples with lower average values of about 3 6 within the modern range the age of the samples approximately 10 500 14c yr b p suggests that the decrease in 18o may manifest climatic changes associated with the younger dryas some combination of increased relative humidity and cooler temperatures with decreased 18o of precipitation during the times of snail activity can explain the decrease in shell 18o a well known paleoindian bison kill occurred at the folsom site during this inferred environmental transition average 13c values of the aragonite shells of the fossil vallonia range from 7 3 to 6 0 among different archaeological levels and are not as negative as modern values this suggests that the proportion of c4 vegetation at the folsom site approximately 10 500 14c yr b p was greater than at present a result which is consistent with other evidence for higher proportions of c4 plants in the region at that time

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

the ksâr akil lebanon mollusc assemblage zooarchaeological and taphonomic investigations abstract shells of marine molluscs exploited by prehistoric humans constitute archives of palaeoecological and palaeoclimatic data as well as of human behaviour in coastal settings here we present our investigations on the mollusc assemblage from ks r akil lebanon a key site in southwestern asia occupied during the middle and upper palaeolithic the site plays an important role in understanding modern human dispersals into eurasia taxa from intertidal rocky shore subtidal soft bottom and rocky littoral habitats dominate the marine component of the invertebrate assemblage terrestrial snails indicate wooded and open half shaded habitats in the vicinity of the site species composition suggests that these habitats were present throughout the upper palaeolithic humans transported marine molluscs to the rockshelter as food packages for dietary purposes e g patella caerulea patella rustica phorcus turbinatus and shells of other taxa to be used as tools e g glycymeris sp or possibly for ornamental purposes e g nassarius gibbosulus and columbella rustica in the initial upper palaeolithic collection focussed on empty shells as raw material for utilitarian purposes in the subsequent early upper palaeolithic and later periods mollusc gathering was performed in an increasing number of habitats and shifted towards collection for human consumption which was the main reason for the introduction of shells to the site during the epipalaeolithic concurrent size shifts of live collected as well as beached specimens suggests that size changes were linked to environmental change rather than to potential overexploitation of dietary taxa by humans

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

human manipulation of terrestrial gastropods in neolithic culture groups of ne morocco abstract shells of terrestrial gastropods helicidae sphincterochilidae are common in rock shelter sediments and open air sites of iberomaurusian to neolithic age in ne morocco excavations at numerous sites in the eastern rif yielded new sites with a rich record of well preserved terrestrial gastropods among which species of the genera otala sphincterochila and alabastrina dominate in sites with sediments younger than 7500 calbp such as taghit haddouch hassi ouenzga ifri oudadane ifri armas and mtlili a high percentage of shells were perforated in a regular manner narrow slots or squarish holes of a few millimetres width cut into the second or third whorl are regularly found in an apical position of the shell we interpret these as evidence of human manipulation of the shell in order to facilitate consumption of the snail body we discuss these new findings in the context of the settlement of this part of north africa by different cultural groups

systematic consumption of non marine gastropods at open air mesolithic sites in the iberian mediterranean region arenal de la virgen and casa corona located in the upper vinalopo valley se of the iberian peninsula are open air mesolithic sites dated to the middle holocene 8600 7800 cal bp recent excavations have provided evidence of non marine assemblages dominated by terrestrial sphincterochila candidissima and iberus alonensis and fresh water gastropods melanopsis tricarinata tricarinata associated with habitation structures these sites represent the first documented cases of systematic land snail consumption at open air residential camps in the iberian mediterranean region this report presents the assemblage composition and modern ethological parameters and discusses taphonomic processes gathering strategies seasonal patterns and their implications in subsistence practices the pattern of occurrence of these species is contrasted with lake environmental records at a local scale to trace paleoecological conditions in the study area

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

shell midden sclerochronology abstract sclerochronological analysis of shell midden faunal remains offers a unique opportunity to study climate and environmental change in relation to human activity middens exist near most aquatic habitats almost worldwide for much of the late pleistocene and holocene they afford good preservation of accretionary calcium carbonate remains such as mollusk shells and fish otoliths in comparatively well dated contexts as such midden samples are a source of sequential proxy records of past climate and environmental conditions and may provide detailed pictures of human environment interaction however midden samples present several challenges to the development and application of sclerochronological proxies including unique taphonomic concerns here these challenges are outlined within descriptions of the major applications of midden sclerochronology archeological concerns including season of capture reconstructing the history of anthropogenic environmental impacts and paleoclimate environment proxy reconstructions

holocene 4 5 1 7 cal kyr bp paleoenvironmental conditions in central argentina inferred from entire shell and intra shell stable isotope composition of terrestrial gastropods the isotopic fingerprint of terrestrial gastropods has been increasingly used as a credible natural paleoenvironmental archive most published work has used this proxy at tropical and temperate latitudes of the northern hemisphere and focused on entire shell analysis the present study provides entire shell and intra shell isotopic profiles to infer average and seasonal late holocene environmental conditions in central argentina 30 s shells of plagiodontes daedaleus gastropoda odontostomidae were retrieved from the alero deodoro roca sector b site one of the few archaeological sites in central argentina rich in shells collected by pre hispanic hunter gatherer groups ancient entire shells exhibited values that were 2 5 higher in 13c and 1 8 higher in 18o than modern individuals pointing to higher abundance of c4 plants and overall drier conditions lower relative humidity and or higher rain 18o during 4 5 1 7 cal kyr bp than today in agreement with published regional proxies intra shel

stable isotope composition of middle to late holocene land snail shells from the marroquies archeological site jaen southern spain paleoenvironmental implications abstract the marroquies archeological site located in the metropolitan area of jaen 37 46 southern spain contains land snail shells which have been preserved jointly with other human and zooarcheological remains new radiocarbon analyses carried out on pristine domestic animal and human bones confirmed that these remains belong to the copper age interval 4470 3880 cal bp n 8 land snail entire shells of two species one herbivorous and one omnivorous were analyzed for 13 c 12 c and 18 o 16 o ratios to estimate the paleoenvironmental conditions prevailing during the middle to late holocene in the southernmost part of europe the 13 c values of fossil shells ranged from 13 8 to 8 1 n 15 whereas modern specimens ranged from 10 8 to 8 6 n 20 the fact that ancient and modern shells generally exhibited similar 13 c values suggests that the 13 c values of the vegetation have remained relatively stable during 4470 3880 cal bp and the present snail species did not differ in 13 c values despite their differing dietary habits the 18 o values of fossil shells ranged from 4 9 to 1 2 n 15 whereas modern specimens ranged from 2 8 to 0 9 n 20 fossil shells were on average 2 lower in 18 o values than modern shells calculations from a snail evaporative steady state flux balance model suggest that shells at 4470 3880 cal bp precipitated under appreciably higher relative humidity conditions than today whereas rain 18 o values and air temperatures at the soil air interface during snail active period were possibly similar although samples from this study represent a time period in which the well documented late holocene aridification trend in southern spain already started snails suggest conditions at 4470 3880 cal bp were yet noticeably wetter than at present this study shows that land snail shells preserved in holocene archeological sites offer valuable paleoenvironmental information in their isotope codes

younger dryas early holocene transition in the south eastern iberian peninsula insights from land snail shell middens the land snail sphincterochila candidissima from archeological records in villena se spain was studied isotopically to estimate the younger dryas yd early holocene transition in the western mediterranean live collected individuals exhibited body 21 8 1 6 and shell 5 8 1 4 d 13 c values typical of a c3 plant diet probably combined with carbonate ingestion calculations of a carbon flux balance mixing model suggest that living specimens experienced similar metabolic rates with comparable ratio of input and output fluxes of bicarbonate from the snail hemolymph all fossil shells showed comparable d 13 c values among each other but values were 2 higher than living specimens this may be explained by higher water stress at the yd holocene transition or by the suess effect shell d 18 o values averaged 1 3 0 8 for living individuals 0 5 0 8 for holocene 8 4 10 2 cal ka bp specimens and 0 4 0 6 for yd 12 0 12 4 cal ka bp snails an oxygen flux balance mixing model suggests that yd shells precipitated during relative humidity rh values of 79 82 after which rh increased gradually reaching maximum values of 87 88 at 8 4 8 6 cal ka bp and from there rh eventually declined to present values of 82 comparisons with other snail data suggest that the xerophilous sphincterochila records different environmental signatures fro other contemporaneous taxa copyright 2013 john wiley sons ltd

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