geochemical and mineralogical control of different genetic types of deep sea nodules from the pacific ocean deep sea nodules from the northeast pacific nodule belt and the southeast pacific sonne basin being formed in areas bordering the equatorial zone of high biological productivity accumulate by two basically different growth processes a early diagenetic growth by supply from pore water and b hydrogenetic growth by supply from near bottom sea water these growth processes lead to different genetic types of nodules early diagenetic type a hydrogenetic type b and mixed type ab a further type ac very rich in mn is being formed by increasing influence of early diagenesis these types can clearly be distinguished by their shapes surface textures mineral constituents of oxide fraction internal microstructures and geochemistry a genetical classification is being proposed on the basis of statistically computed interelement relationships todorokite very poor in fe is the main mn phase in the early diagenetic substance mno2 intimately intergrown with feooh xh2o is the main phase in the hydrogenetic substance consequently an important difference can be pointed out the metal supply for the growth of the early diagenetic nodules is based on an ionic solution of me2 e g mn2 ni2 cu2 zn2 whereas the supply for the hydrogenetic nodules is caused by transport of colloidal particles mobilization of mn2 and fractionation from fe is controlled by the amount of decomposing organic matter in the peneliquid layer of the sediments the main factor controlling the intensity of early diagenesis is the biological productivity in surface waters the crucial point of reversal at a mn fe ratio of about 5 obtained by hyperbolical regression of the analyses of nodules from the southeast pacific represents best concentrations in ni and cu mn fe quotients greater than 5 cause a decrease of ni and cu content nodules from the northeast pacific nodule belt generally contain higher concentrations in cu than nodules from the southeast pacific this can be explained by an additional supply of cu transported below ccd by siliceous plankton

paleoclimate and location of the border between mediterranean climate region and the saharo arabian desert as revealed by speleothems from the northern negev desert israel speleothem bearing karstic caves of the northern negev desert southern israel provides an ideal site for reconstructing the paleoclimate and paleo location of the border between mediterranean climate region and the saharo arabian desert major periods of speleothem deposition representing humid periods were determined by high resolution 230 th u dating and corresponding studies of stableisotopecompositionwereusedtoidentifythesourceofrainfallduringhumidperiodsandthevegetationtype majorhumidintervals

understanding past climatic and hydrological variability in the mediterranean from lake prespa sediment isotope and geochemical record over the last glacial cycle here we present stable isotope and geochemical data from lake prespa macedonia albania border over the last glacial cycle marine isotope stages 5 1 and discuss past lake hydrology and climate tic oxygen and carbon isotopes as well as responses to climate of terrestrial and aquatic vegetation toc rock eval pyrolysis carbon isotopes pollen the lake prespa sediments broadly fall into 5 zones based on their sedimentology geochemistry palynology and the existing chronology the glacial sediments suggest low supply of carbon to the lake but high summer productivity intermittent siderite layers suggest that although the lake was likely to have mixed regularly leading to enhanced oxidation of organic matter there must have been within sediment reducing conditions and methanogenesis mis 5 and 1 sediments suggest much more productivity higher rates of organic material preservation possibly due to more limited mixing with longer periods of oxygen depleted bottom waters we also calculated lakewater 18o from siderite authigenic glacial and calcite endogenic holocene and show much lower lakewater 18o values in the glacial when compared to the holocene suggesting the lake was less evaporative in the glacial probably as a consequence of cooler summers and longer winter ice cover in the holocene the oxygen isotope data suggests general humidity with just 2 marked arid phases features observed in other eastern and central mediterranean lakes

holocene climatic changes in the western mediterranean from south east france to south east spain abstract holocene climatic changes along coastal regions from south east france to south east spain were studied using pollen ratios comparing modern pollen rain vegetation and climate along selected transects from the atlantic ocean to the mediterranean we obtained threshold values of two different ratios corresponding to the different climatic conditions along the transects these pollen ratios and threshold values were employed to characterize the holocene climatic changes from nine mediterranean coastal sites the results were compared with data from marine and continental pollen sequences distributed in the western mediterranean basin and with additional regional data independent of human activity lake level fluctuations alpine glacier advance and retreat chronology 14 c anomaly and cooling phases in eastern france and central europe the role of anthropogenic activities and climate on the changes in vegetation is discussed six major changes in vegetation cover were identified they correspond to aridification phases that occurred around 9500 9000 yr bp 10 900 9700 cal bp 7500 7000 yr bp 8400 7600 cal bp 4500 4000 yr bp 5300 4200 cal bp 3700 3300 yr bp 4300 3400 cal bp 2600 1900 yr bp 2850 1730 cal bp and 1300 1000 yr bp 1300 750 cal bp these arid episodes were regional responses to more global climatic changes and determined the changes in the vegetation cover humans undoubtedly enhanced the vegetation changes but none the less had to adapt to these new climatic conditions

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

lateglacial to holocene trace element record ba mg sr from corchia cave apuan alps central italy paleoenvironmental implications in this study mg ca sr ca and ba ca ratios in a lateglacial to holocene stalagmite cc26 from corchia cave central italy are compared with stable isotope data to define palaeohydrological changes for most of the record the trace element ratios show small absolute variability but similar patterns which are also consistent with stable isotope variations higher trace element to calcium values are interpreted as responses to decreasing moisture inducing changes in the residence time of percolation producing prior calcite precipitation and or variations in the hydrological routing statistically meaningful levels of covariability were determined using anomalies of mg ca d 18 o and d 13 c combining these three time series into a single palaeomoisture trend parameter we highlight several events of reduced moisture ca 8 9 8 4 6 2 4 2 3 1 and 2 0 ka a humid period between ca 7 9 and 8 3 ka and other shorter term wet events at ca 5 8 5 3 and 3 7 ka most of these events can be correlated with climate changes inferred from other regional studies for both extremities of the record i e before ca 12 4 ka and after ca 0 5 ka mg ca and sr ca are anti correlated and show the greatest amplitude of values a likely explanation for which involves aragonite and or gypsum precipitation the latter derived from pyrite oxidation above the cc26 drip point copyright 2014 john wiley sons ltd

a late holocene climate record in stalagmites from modric cave croatia few terrestrial holocene climate records exist from south eastern europe despite its important geographical position as a transitional climatic zone between the mediterranean and mainland continental europe here we present new petrographic and stable isotope data for two holocene speleothems from modric cave croatia 44 15 n 15 32 e a coastal adriatic site 120 m inland modern meteorological and cave conditions have been monitored for 2 years to understand the links between climate variability and stable isotope time series records in speleothems typical of a mediterranean type climate a negative water balance exists between april and september so that recharge of the aquifer is restricted to the winter months the weighted mean 18o of the rainfall is 5 96 2 2 83 and the weighted mean d h rainfall value is 36 83 2 19 95 slightly above the global meteoric water line but well below the mediterranean meteoric water line modern calcite from the tops of each stalagmite exhibits 18o values that are close to isotopic equilibrium with their respective drip water values unfortunately the relatively young ages and low uranium contents ca 50 p p b of both stalagmites hamper the use of u series dating radiocarbon dates have been used instead to constrain their chronology using a dead carbon correction apart from some isotope stage 3 material ca 55 ka both stalagmites were deposited during the late holocene climatic conditions during the late holocene are inferred to have been sufficiently wet to maintain stalagmite growth and any hiatuses appear to be relatively short lived inferred changes in the stalagmite diameters during deposition are linked to 13c and 18o variations indicating alternating periods of drier and wetter conditions drier conditions are inferred for the late roman ages warm period and the mid medieval warm period wetter conditions are associated with the little ice age copyright 2012 john wiley sons ltd

evidence for obliquity forcing of glacial termination ii variations in the intensity of high latitude northern hemisphere summer insolation driven largely by precession of the equinoxes are widely thought to control the timing of late pleistocene glacial terminations however recently it has been suggested that changes in earth s obliquity may be a more important mechanism we present a new speleothem based north atlantic marine chronology that shows that the penultimate glacial termination termination ii commenced 141 000 2500 years before the present too early to be explained by northern hemisphere summer insolation but consistent with changes in earth s obliquity our record reveals that terminations i and ii are separated by three obliquity cycles and that they started at near identical obliquity phases

distinct phases of relative sea level changes in the central adriatic during the last 1500 years influence of climatic variations abstract we present a new sea level reconstruction for the past 1500 years based on biological indicators from the central adriatic islands biogenic littoral rims built by the coralline rhodophyte lithophyllum byssoides were found on the particularly exposed sites on the rocky coasts of the islands of vis ravnik and bisevo in croatia the presence of thick and well developed lithophyllum rims considered to be precise 10 cm sea level indicators points directly to the rising sea level environment biogenic rims were mapped measured and sampled for 14c dating the obtained results point to four phases of sea level changes the sea level was near stable from around 550 till 770 cal ad in the dark ages cold period dacp then during the medieval climate anomaly mca 770 till 1330 cal ad the sea level increased at a rate of 0 71 mm yr during the little ice age lia 1330 till 1640 cal ad it was near stable again later the sea level started to rise at a much higher rate particularly during the current warm period cwp these data were compared with local predictions derived from a glacio hydro isostatic models associated with the last glacial cycle if the isostatic eustatic component is separated this area seems to have almost stable tectonic conditions during the past 1500 years our results show that the large algal rims most likely grew during near stable sea level conditions that occurred during two relatively colder periods in the past 1500 years they also reveal that well developed up to 1 8 m wide upper levels of algal rims were formed during 300 years of stabilisation throughout the lia

late quaternary paleoclimate in the eastern mediterranean region from stable isotope analysis of speleothems at soreq cave israel abstract the eastern mediterranean continental paleoclimate during the past 25 000 years was determined by a high resolution petrographic stable isotopic and age study of speleothems from soreq cave israel 18o 13c trends indicate that all speleothems older than 7000 yr formed under conditions that differ from those of today the period from 25 000 to 17 000 yr b p was characterized by the highest 18o and 13c values which indicate deposition at temperatures of 12 16 c annual rainfall of 300 450 mm and vegetation typical of a mixed c3 c4type from 17 000 to 10 000 yr b p deglaciation in northern europe 18o values dropped progressively correlative with warming 2 3 c and a gradual increase in precipitation a simultaneous decrease in 13c gives a range expected for c3 type vegetation this period also shows significant 18o and 13c spikes which are correlatable with global events e g heinrich events and the younger dryas stade the speleothems that grew between 10 000 and 7000 yr b p have a unique petrography showing irregular thin laminae of various colors and much detritus they have the lowest 18o corresponding to 1000 mm rain coupled with the highest 13c caused by flooding events which stripped the soil cover from 7000 to 1000 yr b p conditions became closer to those of today this study demonstrates that global events which were recognized in northern europe and north africa are also evident in the eastern mediterranean and are reflected principally by large changes in the rainfall rate

palaeolithic landscapes of europe and environs 150 000 25 000 years ago an overview abstract when considering the evolution and migrations of neandertalers and early modem human beings the harsh conditions of the last glacial maximum are often implicitly or explicitly assumed as their environmental background this perception is false the conditions of the high glacial apply to a small fraction of late pleistocene time here we review the palaeoenvironmental history of europe from 150 000 to 25 000 years ago with the aid of data from long cores of ice and marine and continental sediments the results are displayed in four sketch maps that illustrate the landscapes of an interglacial glacial cycle the maps connected by palaeoenvironmental histories show that especially between 60 000 and 25 000 years ago a critical part of the palaeolithic the glacial landscapes were for much of the time less barren than is generally assumed but numerous climate changes on a scale of several millennia are evident placing a premium on accurate dating of the co evolution of humans and landscape moreover during the glacial interval abrupt climatic changes lasting from a century to a few millennia were common their importance for landscape changes and their impact on human activity remain to be ascertained

paleoclimate and growth rates of speleothems in the northwestern iberian peninsula over the last two glacial cycles abstract speleothem growth requires humid climates sufficiently warm to stimulate soil co2 production by plants we compile 283 u th dates on 21 stalagmites from six cave systems in the nw coast of spain to evaluate if there are patterns in stalagmite growth that are evidence of climatic forcing in the oldest stalagmites from marine oxygen isotope stage mis 7 5 growth persists through the glacial period hiatuses and major reductions in growth rate occur during extreme minima in summer insolation stalagmites active during the last interglaciation cease growth at the mis 5 4 boundary 74 ka when regional sea surface temperature cooled significantly during mis 3 only two stalagmites grew rates were highest between 50 and 60 ka during the maximum in summer insolation one stalagmite grew briefly at 41 ka 36 5 and 28 6 ka all during warm phases of the dansgaard oeschger cycles a pronounced holocene optimum in stalagmite growth occurs from 9 to 6 ka the cessation of most growth by 4 1 ka coincident with broad increases in aridity over the mediterranean and areas influenced by the north african monsoon suggest that regions such as nw spain with dominant atlantic moisture sources also experienced increased aridity at this time

abrupt post glacial climate events in west asia and north africa monsoon domains regions beyond the present or past penetration of the indian and african monsoons have experienced several large and abrupt climatic fluctuations over the past 13 14c kyr pollen and lake records from west asia western tibet and rajasthan east africa ethiopia and west africa western sahara sahel and subequatorial africa were selected on the basis of chronological control sensitivity of both site and environmental indicators to climate change the continuity of the record and interdisciplinary control of the palaeoclimatic interpretation conditions wetter than those of today prevailed during the early mid holocene period but major dry spells are recorded at all sites during the intervals 11 0 9 5 kyr bp 8 7 kyr bp and 3 4 kyr bp several records also suggest dry events of minor amplitude around 6 kyr bp potential boundary forcings of insolation and sea surface and tropical land surface conditions are discussed the solar radiation accounts for the general envelop of the post glacial monsoon fluctuations but explains neither the timing nor the amplitude of the short term changes in spite of apparent covariation between fluctuations in sea surface conditions in the north atlantic and the monsoon record no direct mechanism could be found relating the intensity of the oceanic thermohaline conveyor belt to the monsoon strength changes in tropical land surface conditions soil moisture negative feedback and changes in ch4 production from wetlands provide a more satisfactory hypothesis for explaining abrupt reversal events

holocene climate variability in europe evidence from δ18o textural and extension rate variations in three speleothems time series o isotope profiles for three u th dated stalagmites have revealed that for much of the holocene a site on the atlantic seaboard sw ireland exhibits first order 18o trends that are almost exactly out of phase with coupled 18o curves from two southern european sites se france and nw italy in the irish stalagmite cc3 from crag cave sw ireland low 18o at 10 000 cal yr bp reflects cool conditions by the early to mid holocene 9000 6000 cal yr bp 18o had increased reflecting the onset of warmer conditions on the atlantic seaboard this shift to higher 18o was accompanied by a marked increase in the stalagmite extension rate reinforcing our interpretation that this was a period of relative warmth except for an episode of increased extension rate about 5500 yr ago 18o in the crag stalagmite exhibits a gradual decrease accompanied by declining extension rates between 7800 and 3500 cal yr bp interpreted as a cooling trend there is evidence for increases in both 18o and stalagmite extension rate in the period from 3500 cal yr bp to the present day suggesting a return to warmer conditions on the atlantic seaboard in the stalagmite from nw italy er76 grotta di ernesto trentino province the early holocene c 9200 7800 cal yr bp is characterised by high 18o probably indicative of warm and or dry conditions exceptionally low 18o from 7800 to 6900 cal yr bp at this site reflects a well defined wet phase cerin wet phase in the last three millennia this stalagmite exhibits a shift to lower 18o interpreted as some combination of cooler and or wetter conditions unlike the irish stalagmite the italian sample does not show a correlation between 18o and extension rate instead its extension rate correlates roughly with 13c presumably reflecting a climate driven vegetation change in the early holocene 18o in the french stalagmite cl26 grotte de clamouse herault province se france was low relative to its holocene average for much of the period since c 3500 cal yr bp this stalagmite exhibits higher 18o than in the early holocene suggesting warmer conditions like the irish stalagmite the french sample exhibits a well defined correlation between 18o and extension rate had drip water availability been the dominant control on 18o at this semi arid site then higher 18o would have been accompanied by lower not higher extension rates this suggests strongly that temperature rather than rainfall amount was the dominant control at this site while conclusions regarding the patterns of climate variability on a continent scale must remain tentative because of the limited number of stalagmites studied we argue that early holocene warm conditions on the atlantic seaboard irish site coincided with relatively cool conditions at the clamouse site by c 3500 yr ago the pattern appears to have been reversed

speleothems and climate a special issue of the holocene speleothems cave dripstones are formed as a part of the meteoric water cycle and therefore vari ations in their growth rate and composition reflect environmental changes on the land surface above the cave since they are continental deposits and possess a remarkably accurate dating potential using tims u series techniques speleothems are important palaeoclimatic archives for the terrestrial environment complementing the marine and ice core records the climatic proxies that can be deciphered from speleothems are growth rate stable isotope composition d18o d13c organic humic matter and trace element composition as well as luminescent laminae which may display annual rhythms the nine papers in this special issue oftheholocene present the latest results in palaeoclimatic analysis from speleothems

late holocene drought responsible for the collapse of old world civilizations is recorded in an italian cave flowstone a severe drought in parts of low latitude northeastern africa and southwestern asia 4200 yr ago caused major disruption to ancient civilizations stable isotope trace element and organic fluorescence data from a calcite flowstone collected from the well watered alpi apuane karst of central western italy indicate that the climatic event responsible for this drought was also recorded in mid latitude europe although the timing of this event coincides with an episode of increased ice rafted debris to the subpolar north atlantic the regional ocean atmosphere response seems atypical of similar holocene ice rafting events furthermore comparison of the flowstone data with other regional proxies suggests that the most extreme part of the dry spell occurred toward the end of a longer term climate anomaly

timing and hydrological conditions of sapropel events in the eastern mediterranean as evident from speleothems soreq cave israel this paper explores the connection between the timing of sapropel events in the eastern mediterranean sea and the time of low 18o events in speleothems of the soreq cave israel a new well dated 18o and 13c profile of the soreq cave speleothems for the last 140 kyr reveals five prominent low 18o events dated at 124 to 119 kyr with the main peak at 122 kyr event v 108 to 100 kyr with peaks at 107 and 102 kyr event iv 85 to 79 kyr with peak at 80 kyr event iii 55 to 52 kyr with a peak at 54 kyr event ii and 8 5 to 7 kyr with peaks at 8 5 and 7 kyr event i these events are characteristic of period of enhanced rainfall in the eastern mediterranean area particularly so for events v and i where the marked decrease in 18o and the correspondingly marked increase in 13c indicate very wet conditions the chronology of the low 18o events v iv iii and i match the ages estimated for the formation of sapropels s5 s4 s3 and s1 which are also associated with high hydrological activity thus it is suggested that the low 18o events in the soreq cave speleothems constrain the maximum duration of the sapropel formation pollen data from the sapropel layers and the isotopic pattern of the speleothems indicate that sapropels s5 and s1 were deposited during very wet periods when there were major decrease in the sea surface salinity coupled with frost free winters and drought free summers sapropels s4 and s3 were formed during periods of increased precipitation but ones in which the general climate was mediterranean semi arid

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

late holocene climate variability in the adriatic sea central mediterranean planktic and benthic foraminifera assemblages from a set of sediment cores collected on the adriatic shelf and the southern adriatic deep basin provide compelling evidence of submillennial scale environmental changes during the last 6000 years repeated peaks in globigerinoides sacculifer represent warm dry intervals including the mediaeval warm period the roman age the late bronze age and the copper age the last occurrence lo of g sacculifer 550 years bp approximates the base of the little ice age lia significant turnovers in the structure of the water column reflect changes in the rate of formation and depth of flow of the north adriatic dense water naddw and the levantine intermediate water liw about 7500 years bp the benthic oxygen isotope records mark the timing when the naddw formation intensified on the slope and shifted to its modern route about 5500 years bp when sea level reached its modern high stand oxygen isotope records of intermediate planktic dwellers indicate a northward intrusion of the liw on the slope the oscillating isotope trends during the last five millennia document a discontinuous invasion of liw into the central adriatic possibly reflecting short term climate changes with weakened liw production during colder and wetter intervals

speleothem evidence for late holocene climate variability and floods in southern greece abstract we present stable isotope data 18o 13c from a detrital rich stalagmite from kapsia cave the peloponnese greece the cave is rich in archeological remains and there are reasons to believe that flooding of the cave has directly affected humans using the cave using a combination of u th and 14c dating to constrain a site specific correction factor for 232th 238u detrital molar ratio a linear age model was constructed the age model shows that the stalagmite grew during the period from ca 950 bc to ca ad 830 the stable oxygen record from kapsia indicates cyclical changes of close to 500 yr in precipitation amount with rapid shifts towards wetter conditions followed by slowly developing aridity superimposed on this signal wetter conditions are inferred around 850 700 500 and 400 100 bc and around ad 160 300 and ad 770 and driest conditions are inferred to have occurred around 450 bc ad 100 150 and ad 650 detrital horizons in the stalagmite indicate that three major floods took place in the cave at 500 bc 70 bc and ad 450 the stable carbon isotope record reflects changes in biological activity being a result of both climate and human activities

holocene atmosphere ocean interactions records from greenland and the aegean sea we compare paleoclimate proxy records from central greenland and the aegean sea to offer new insights into the causes timing and mechanisms of holocene atmosphere ocean interactions a direct atmospheric link is revealed between aegean sea surface temperature sst and high latitude climate the major holocene events in our proxies of aegean sst and winter spring intensity of the siberian high gisp2 k record follow an 2300 year spacing recognised also in the 14c record and in worldwide holocene glacier advance phases suggesting a solar modulation of climate we argue that the primary atmospheric response involved decadal centennial fluctuations in the meridional pressure gradient driving aegean sst events via changes in the strength duration and or frequency of northerly polar continental air outbreaks over the basin the observed natural variability should be accounted for in predictions of future climate change and our timeframe for the aegean climate events in addition provides an independent chronostratigraphic argument to middle eastern archaeological studies

speleothem record of the last 180 ka in villars cave sw france investigation of a large δ18o shift between mis6 and mis5 the vil car 1 flowstone core from villars cave sw france provides one of the first european speleothem records extending back to 180 ka based on ueth tims and mc icp ms measurements the core offers a continuous record of termination ii and the last interglacial the penultimate deglaciation is characterized by a prominent 5 depletion in calcite d 18 o determining which specific environmental factors

palaeoclimatic implications of the growth history and stable isotope delta o 18 and delta c 13 geochemistry of a middle to late pleistocene stalagmite from central western italy the age structure and stable isotope composition of a stalagmite cc i from an upland cave in central western italy were studied to investigate regional response to global climatic changes four growth phases are constrained by 28 thermal ionization and multi collector inductively coupled plasma mass spectrometry th u ages and reveal intermittent deposition through the period between marine isotope stage mis 11 and 3 similar to380 and similar to43 kyr most of the growth took place between similar to380 and similar to280 kyr a period punctuated briefly by a hiatus in deposition through the glacial maximum of mis 10 growth was terminated abruptly at 280 kyr just prior to the mis 8 glacial maximum with a present day chamber temperature of 7 5 degreesc the timing of hiatuses close to these glacial maxima point to freezing conditions at the time no deposition was recorded through the entirety of mis 7 and most of mis 6 whilst two minor growth phases occurred at similar to141 125 and similar to43 kyr growth at 141 kyr indicates temperatures 0 degreesc at a time when mis 6 ice volumes were close to their maximum high stable carbon isotope delta 13 c values similar to2 8parts per thousand to 3 1parts per thousand throughout the stalagmite s growth reflect a persistently low input of biogenic co2 indicating that the steep barren and alpine like recharge area of today ha s been in existence for at least the last similar to380 kyr during mis 9 the lowest delta 13 c values occur well after maximum interglacial conditions suggesting a lag in the development of post glacial soils in this high altitude karst the stable oxygen isotope delta 18 o trends match the main structural features of the major climate proxy records specmap vostok and devils hole suggesting that the delta 18 o of cc1 has responded to global scale climate changes whilst remarkable similarity exists between cc1 delta 18 o and regional sea surface temperature reconstructions from north atlantic core odp980 and southwest pacific marine core md97 2120 through the most detailed part of the cc1 record mis 9 8 the results suggest that cc1 and other stalagmites from the cave have the potential to capture a long record of regional temperature trends particularly in regards to the relative severity of pleistocene glacial stages c 2004 elsevier b v all rights reserved

mid holocene climate variations revealed by high resolution speleothem records from soreq cave israel and their correlation with cultural changes mid holocene 7000 4000 yr bp paleoclimate conditions were reconstructed for the eastern mediterranean region through a high resolution 3 20 yr oxygen and carbon isotopic record in a speleothem

high resolution palynological record off the iberian margin direct land sea correlation for the last interglacial complex abstract we present high resolution pollen dinocyst and isotopic data for the last interglacial complex from marine core md952042 southwestern margin of the iberian peninsula 37 48 n 10 10 w 3148 m direct land sea correlation from this core indicates that during this period north atlantic sea surface temperatures were in phase with iberian climate our palynological analysis suggests a younger dryas like event at the marine isotope stage mis 6 5 transition the analysis also indicates that the eemian spans from the lightest isotopic values of mis 5e ca 126 ky bp to the heavier isotopic values towards the mis 5e 5d transition therefore the eemian is not entirely equivalent to mis 5e pollen analysis identifies four climatic phases of low amplitude during the eemian a mediterranean climate in southwestern europe is gradually replaced by oceanic conditions the middle of the eemian is characterized by an increase in precipitation on the land and ocean associated with a slight cooling this seems to be the result of a displacement of the polar front as far south as southern europe during this period after the eemian three relatively short climatic phases on land melisey i st germain ia and montaigu cold event occurred contemporaneously with three shifts of sea surface temperatures the montaigu event first identified in terrestrial pollen sequences is therefore also recorded in core md952042 on the basis of pollen dinocyst and planktonic isotopic data our results also show that the warm periods of mis 5 are not characterized by similar climatic conditions on land

all age depth models are wrong but how badly the uncertainty and error associated with fitted age depth models were investigated by fitting a range of models to sets of simulated radiocarbon dates based on varved sediments and comparing the modelled relationship with the varve timescale with large numbers of dates cubic smooth splines out perform other models with few dates no model reliably provides a good fit to reality and calculated confidence intervals are over optimistic c 2003 elsevier ltd all rights reserved

tephrostratigraphy chronology and climatic events of the mediterranean basin during the holocene an overview the identification and characterisation of high frequency climatic changes during the holocene requires natural archives with precise and accurate chronological control which is usually difficult to achieve using only 14c chronologies the presence of time spaced tephra beds in quaternary mediterranean successions represents an additional independent tool for dating and correlating different sedimentary archives these tephra layers are potentially useful for resolving long standing issues in paleoclimatology and can help towards correlating terrestrial and marine paleoclimate archives known major tephras of regional extent derive from central and southern italy the hellenic arc and from anatolia a striking feature of major holocene tephra deposition events in the mediterranean is that they are clustered rather than randomly distributed in time several tephra layers occurred at the time of the s1 sapropel formation between c 8 4 and 9 0 ka bp mercato gabellotto fiumebianco e1 cappadocia and ot

regional climate variability and ecosystem responses to the last deglaciation in the northern hemisphere from stable isotope data and calcite fabrics in two northern adriatic stalagmites abstract geochemical and physical changes along the growth axis of speleothems are controlled by climate as well as the dynamics of the host karst system discriminating between the two is one of the major challenges in assembling robust cave palaeoclimate records overcoming this dilemma may be achieved by investigating multiple properties from two or more speleothems from the same cave spanning the same time interval in this study we use high resolution stable oxygen and carbon isotope 13c and 18o morphological and petrographic data from two calcite stalagmites sv1 and sv7 from grotta savi italy to help constraining the regional climate conditions during the younger dryas the new sv1 record spanning 15 3 9 4 ka builds on a previously published low resolution stable isotope time series it is anchored by 22 new u th ages and lamina counting yielding a refined age model that supersedes the previous one the sv7 record is anchored by 8 u th ages and spans 13 1 10 5 ka partially overlapping the sv1 record together the morphological and geochemical characteristics of sv1 and sv7 allow us to identify site specific processes driving the isotopic variations this enables us to explore the degree of complacency in speleothems whereby periodically a speleothem is insensitive to recording a climate signal due to aquifer hydrology and network evolution the model suggests that 18o is a proxy for the infiltration amount that reaches the site of deposition which in the case of sv7 was buffered by the aquifer hydrology the interpretation of 13c in both stalagmites is more complex being influenced by both temperature and hydrology only a comparison of the two stalagmite records allows us to recognise a decoupling between the effects of hydrology and temperature according to our interpretation the most distinctive climate information of the younger dryas was the high hydrological variability with phases dominated by seasonal infiltration within an overall cooling trend our record also reveals a significant early holocene climate anomaly centred at 10 4 ka whose magnitude was possibly amplified by local synoptic conditions our research demonstrates the importance of investigating several complementary proxies particularly from morphologically diverse stalagmites when monitoring data are not available fabric and lamina thickness can be fundamental to unravelling the dominant control of hydrology or temperature on stable isotopes

late pleistocene holocene sea level rise and the pattern of coastal karst inundation records from submerged speleothems along the eastern adriatic coast croatia in order to reconstruct the late pleistocene holocene sea level rise along the eastern adriatic coast eight speleothems were collected from three submerged caves along the croatian coast from depths of 38 5 to 17 m the marine biogenic overgrowth layer and the youngest and the oldest parts of the speleothems were dated by the 14c method their stable isotope 13c 12c and 18o 16o contents were also measured from the measured 14c activity of the marine overgrowth and using the model of alessio et al 1992 risultati preliminari relativi alla datazione di speleotemi sommersi nelle fasce costiere del tirreno centrale giornale di geologia ser 3 54 2 165 193 the start of overgrowth i e the time of flooding by seawater was determined to be 10 185 cal bp at 36 m 9160 cal bp at 34 m and 7920 cal bp at 23 m our results partially match the sea level curves reconstructed for adjacent areas tyrrhenian coast and french mediterranean coast however the start of the marine overgrowth on speleothems in pit caves indicates strong dependence on the steepness of the terrain on steep extensively karstified coasts marine overgrowths on speleothems coincided with the submersion of the speleothems due to the relatively short distance between the pit and the open sea and fast penetration of seawater into the pit in contrast marine overgrowths on speleothems in pits in the flat terrains occurred later because speleothem growth ceased due to flooding with fresh groundwater later the fresh water was replaced by seawater due to the greater distance of the inland pits to the former coast

a 53 year seasonally resolved oxygen and carbon isotope record from a modern gibraltar speleothem reconstructed drip water and relationship to local precipitation abstract the response of a climate proxy against measured temperature rainfall and atmospheric circulation patterns at sub annual resolution is the ultimate test of proxy fidelity but very few data exist showing the level of correspondence between speleothem climate proxies and the instrumental climate record cave sites on the gibraltar peninsula provide a unique opportunity to calibrate speleothem climate proxies with the longest known available precipitation isotopes and instrumental records an actively growing speleothem sampled from new st michaels cave in 2004 is composed of paired laminae consisting of light columnar calcite and a darker microsparitic calcite stable isotope analysis of samples micromilled in 100 m steps at the equivalent of bi monthly intervals reveals fabric correlated annual cycles in carbon isotopes oxygen isotopes and trace elements responding to seasonal changes in cave microclimate hydrology and ventilation patterns calcite 13 c values reach a minimum in the light columnar fabric and evidence from trace element behaviour and cave monitoring indicates that this grows under cave winter conditions of highest p co 2 whereas the dark microsparitic calcite characterised by elevated 13 c and 18 o values grows under low summer p co 2 conditions drip water 13 c dic reaches a minimum in march april at which time the attenuated 18 o signal becomes most representative of winter precipitation an age model based on cycle counting and the position of the 14 c bomb carbon spike yields a precisely dated winter oxygen isotope proxy of cave seepage water for comparison with the gnip and instrumental climate record for gibraltar the 18 o characteristics of calcite deposited from drip water representing winter precipitation for each year can be derived from the seasonally resolved record and allows reconstruction of the 18 o drip water representing winter precipitation for each year from 1951 2004 these data show an encouraging level of correspondence r 2 0 47 with the 18 o of rainfall falling each year between october and march and on a decadal scale the 18 o of reconstructed winter drip water mirrors secular change in mean winter temperatures

hydrological conditions over the western mediterranean basin during the deposition of the cold sapropel 6 ca 175 kyr bp a new oxygen isotope record is reported from a stalagmite collected in the argentarola cave located on the tyrrhenian coast of italy as shown from observations and numerical modeling of n 18 o in modern precipitation the recorded n 18 o variability for this zone is dominated by the amount of precipitation so called amount effect the n 18 o profile measured in the stalagmite is characterized by a prominent negative excursion ca 2 3x between 180 and 170 kyr bp this paleoclimatic feature is interpreted as being due to a relatively wet period which occurred during the penultimate glacial period more precisely during marine isotope stage 6 5 this pluvial phase is shown to correspond chronologically to the deposition of the sapropel event 6 s6 although this particular sapropel event occurred during a cold phase the n 18 o excursion is similar to those corresponding to other sapropels s4 s3 and s2 the evidence for humid conditions during s6 in the western mediterranean basin agrees with previous studies based on deep sea sediment cores taken collectively the data suggest that during sapropel events dilution of ocean surface waters was not restricted to the output of the river nile but was rather widespread over the entire mediterranean sea due to increased rainfall 2002 elsevier science b v all rights reserved

late glacial to holocene climate change and human impact in the mediterranean the last ca 17ka diatom record of lake prespa macedonia albania greece lake prespa macedonia albania greece occupies an important location between mediterranean and central european climate zones although previous multi proxy research on the late glacial to holocene sequence core co1215 320 cm ca 17 cal ka bp to present has demonstrated its great value as an archive of quaternary palaeoclimate data some uncertainty remains in the interpretation of climate change with the exception of oxygen stable isotope data previous palaeolimnological interpretation has relied largely on proxies for productivity here existing interpretation is strengthened by the addition of diatom data results demonstrate that shifts in diatom assemblage composition are driven primarily by lake level changes and thus permit more confident interpretation of shifts in moisture availability over time while corroborating previous interpretation of catchment and climate induced productivity shifts an inferred cold arid shallow lake phase between ca 17 1 and 15 7 cal ka bp is not only followed by a high productivity phase from ca 15 7 cal ka bp with late glacial warming but also is the first evidence for a gradual increase in lake level in line with other regional records clear evidence for a younger dryas climate reversal between ca 13 1 and 12 3 cal ka bp is followed by an unusually gradual transition to the holocene and deeper oligotrophic mesotrophic lake conditions are reached by ca 11 0 cal ka bp in contrast to the arid episode from ca 10 0 to 8 0 ka inferred from positive 18 ocalcite values rapid diatom inferred lake level increase after the start of the holocene suggests high moisture availability in line with palynological evidence but with only very subtle evidence for the impact of an 8 2 ka cold event the maintenance of high lake levels until 1 9 cal ka bp and the peak of inferred humidity from ca 7 9 to 6 0 cal ka bp matches the oxygen stable isotope profile and confirms that the latter is driven primarily by evaporative concentration rather than reflecting regional shifts in precipitation sources over time during the late holocene progressive eutrophication is inferred between 1 9 and present two shallow phases at ca 1 0 cal ka bp and at ca 100 years ago probably represent an aridity response which is added to increase human impact in the catchment overall the study is important in confirming previous tentative inferences that late glacial to holocene moisture availability has strong affinity with other sites in the eastern mediterranean it also tracks the pattern of north atlantic forcing

carbon transfer dynamics from bomb 14c and δ13c time series of a laminated stalagmite from sw france modelling and comparison with other stalagmite records twenty two ams 14c measurements have been made on a modern stalagmite from sw france in order to reconstruct the 14c activity history of the calcite deposit annual growth laminae provides a chronology up to 1919 a d results show that the stalagmite 14c activity time series is sensitive to modern atmosphere 14c activity changes such as those produced by the nuclear weapon tests the comparison between the two 14c time series shows that the stalagmite time series is damped its amplitude variation between pre bomb and post bomb values is 75 less and the time delay between the two time series peaks is 16 years 3 a model is developed using atmosphere 14c and 13c data fractionation processes and three soil organic matter components whose mean turnover rates are different the linear correlation coefficient between modeled and measured activities is 0 99 these results combined with two other stalagmite 14c time series already published and compared with local vegetation and climate demonstrate that most of the carbon transfer dynamics are controlled in the soil by soil organic matter degradation rates where vegetation produces debris whose degradation is slow the fraction of old carbon injected in the system increases the observed 14c time series is much more damped and lag time longer than that observed under grassland sites the same mixing model applied on the 13c shows a good agreement r2 0 78 between modeled and measured stalagmite 13c and demonstrates that the suess effect due to fossil fuel combustion in the atmosphere is recorded in the stalagmite but with a damped effect due to som degradation rate the different sources of dead carbon in the seepage water are calculated and discussed

the holocene climatic evolution of mediterranean italy a review of the continental geological data we present a synthesis of geological stratigraphic geomorphological and stable isotope data collected from continental archives to highlight the environmental and climatic differences between the first and second half of the holocene of central and southern italy the beginning of the holocene is marked by rapid environmental change in mediterranean italy between c 9500 cal bp and c 6000 5500 cal bp average temperatures were probably higher and environmental conditions were generally stable between c 9000 and 7000 cal bp meteoric precipitation was at its highest the end of the wetter period seems to occur later at c 6000 5000 cal bp since c 6000 5000 cal bp rapid climatic excursions are apparent in different palaeoclimate proxies with both variability in meteoric precipitation and temperature evident of particular relevance is the event occurring at c 4200 cal bp this event heralds a period of significant environmental change in the apennines and more generally in central italy

confidence intervals for age estimates and deposition times in late quaternary sediment sequences distribution sampling from sequences of radiocarbon ages is used to obtain confidence intervals for intermediate age estimates sediment deposition times and thence pollen deposition rates three

the eastern mediterranean paleoclimate as a reflection of regional events soreq cave israel the climate of the eastern mediterranean region of the last 60 ky was determined by a high resolution study of the oxygen and carbon isotopic composition 1500 measurement pairs of speleothems from the soreq cave israel with chronology provided by 53 precise 230 th 234 u tims ages the high precision of the speleothem tims ages permits us to determine the timing of regional climatic events in the eastern mediterranean region and to see if they correlate with global events during the period from 60 to 17 ky the 18 o and 13 c values were generally 2 2 5 higher than during the period from 17 ky to present this is consistent with the climatic transition from glacial to interglacial within the 60 to 17 ky period the soreq cave stable isotope profile includes four cold peaks at 46 35 25 and 19 ky and 2 warm peaks at 54 and 36 ky in addition the period 17 ky has two more cold peaks at 16 5 and from 13 2 to 11 4 ky the ages of four of the six cold peaks correlate well with the ages of three heinrich events h1 h2 h5 and with the age of the younger dryas however the other two heinrich events are not reflected in the soreq cave record several other isotope peaks which appear during the last 7 ky are contemporaneous with regional climatic events in the middle east and north africa in addition to the drop in 18 o and 13 c observed between the last glacial and the holocene sharp simultaneous drops in 234 u 238 u 0 ratios sr concentrations and in 87 sr 86 sr are also observed suggesting that the latter are climate related these variations are interpreted in terms of major changes in the temperature the mean annual rainfall and its isotopic composition the isotopic composition of the mediterranean vapor source the soil moisture conditions and in the mixing proportions of sources with different 87 sr 86 sr ratios sea spray dust particles and dolomitic host rock

holocene lake development of two dalmatian lagoons malo and veliko jezero isle of mljet in respect to changes in adriatic sea level and climate abstract within the austrian igbp pages project palaeolimnology of adriatic alpine lakes paal geochemical and diatom analyses were performed on sediment cores of malo and veliko jezero two karstic coastal lakes on the island mljet croatia combined with diatom calibration they provide evidence of remarkable environmental changes during the holocene the formation of the lakes in the early holocene was triggered by a rise in the adriatic sea level from approximately 50 to 30 m which resulted in the transmission of seawater through karst and by a temporary increase in precipitation the onset of this pluvial period was dated in malo jezero at 8 4 kyr b p and had its maximum approximately 7 6 kyr b p it was briefly interrupted by a dryer episode from about 7 2 until 7 1 kyr b p between 6 and 5 5 kyr b p a transition to the present mediterranean climate occurred the marine ingression into veliko jezero through the soline channel with a present depth of 2 5 m took place about 5 kyr b p from 5 to 4 kyr b p the oscillating sea level gradually approached the present value a tephra layer at 7 3 kyr b p in both lakes was related to sudden environmental changes that were probably caused by tectonic movements accompanying italian volcanism

origin and type of rainfall for recharge of a karstic aquifer in the western mediterranean a case study from the sierra de gador campo de dalias southeast spain isotope signatures in precipitation from the global network for isotopes in precipitation around the mediterranean basin and literature data are compared with isotopic data from a large karstic aquifer in southeast spain to explain the origin and type of the precipitation events dominating recharge analysis of the deuterium excess d at the scale of the mediterranean basin and at the regional scale allows us to understand the isotopic context of the study area campo de dalias and the sierra de gador almerfa province the origin of precipitation can be determined from its d value the d value changes as a function of the initial evaporation condition it depends on the relative humidity and temperature during the evaporation producing the water vapour of the clouds the water vapour which dominates the study area is generated in two areas the atlantic ocean d 10 parts per thousand and the western mediterranean basin d 15 parts per thousand with increasing precipitation volume the western mediterranean character dominates these heavier storms contribute mainly to recharge as illustrated by the d value of 13 6 parts per thousand in deep groundwater of the campo de dalias weighted d values increase with the volume of precipitation giving a significant relationship for the southern and eastern coasts of the iberian peninsula this selectivity of d to monthly precipitation was used to estimate the return period of precipitation leading to aquifer recharge at 0 9 4 9 years moderate rainfall which occurs more frequently still represents similar to 60 90 of the total precipitation one of the challenges to meet ever growing water demands is to increase recharge from moderate events yielding intermediate quantities per event but forming the bulk of the annual precipitation copyright c 2006 john wiley sons ltd

sea level change during mis 5a based on submerged speleothems from the eastern adriatic sea croatia abstract two stalagmites were collected from below sea level in u vode pit on the krk island eastern adriatic sea at elevations of 14 5 and 18 8 m they exhibit a growth history indicating a double high sea level stand during marine isotope stage mis 5a 87 77 ka thin layers of halite and gypsum were found to be associated with hiatuses in speleothem growth probably caused by seawater inundation during sea level highstands these mineral deposits are likely to have been precipitated during marine regression phases under evaporitic conditions we constrain the age of the speleothem growth below and above growth hiatuses and hence timing of possible marine incursions using multi collector inductively coupled plasma mass spectrometry mc icpms u th techniques age estimates indicate that during mis 5a relative sea level elevations were greater than 14 5 m from 87 to 82 ka and 18 8 m from 77 to 64 ka and constrained to be lower than 18 8 m from 93 to 90 ka 82 to 77 ka and 64 to 54 ka assuming no tectonic adjustment however present speleothem depths could indicate long term regional tectonics

paleoclimate reconstruction based on the timing of speleothem growth and oxygen and carbon isotope composition in a cave located in the rain shadow in israel high resolution th 230 u 234 ages and delta 18 o and delta 13 c compositions of speleothems in ma ale efrayirn cave located to the east of the central mountain ridge of israel enable us to examine the nature of the rain shadow aridity during glacial and interglacial intervals speleothem growth occurred during marine glacial isotopic periods with no growth during the two last marine isotope interglacial intervals and during the peak of the last glacial maximum this contrasts with speleothem growth in caves located on the western flank of the central mountain ridge in the eastern mediterranean semiarid climatic zone which continued throughout the last 240 000 yr thus during glacial periods water reached both sides of the central mountain ridge a comparison of the present day rain and cave water isotopic compositions and amounts at the ma ale efrayim cave site with those on the western flank shows that evaporation and higher temperatures on the eastern flank are major influences on isotopic composition and the lack of rainfall the delta 18 o and delta 13 c profiles of the speleothems deposited between 67 000 and 25 000 yr b p match the general trends of the isotopic profiles of soreq cave speleothems suggesting a similar source eastern mediterranean sea and similar climatic conditions thus during glacial periods the desert boundary effectively migrated further south or east from its present day location on the eastern flank whereas interglacial periods appear to have been similar to the present with the desert boundary at the same position the decrease in overall temperature and a consequent reduction in the evaporation to precipitation ratios on the eastern flank are viewed as the major factors controlling the decay of the rain shadow effect during glacial periods c 2003 elsevier science usa all rights reserved

holocene climatic conditions in the eastern adriatic recorded in stalagmites from strasna pec cave croatia abstract in the study we present results of stable isotope analysis 18o 13c of two stalagmites spd 1 and spd 2 from strasna pec cave situated on dugi otok island in the central adriatic region the growth interval of the speleothems based on u th dating covers the period from 4 4 ka to 1 5 ka both speleothems show frequent 18o and 13c fluctuations with similar average values 18o value of 4 for both speleothems and average value of 13c 8 5 and 8 8 respectively in order to reconstruct the holocene climatic conditions in the eastern adriatic the speleothem isotopic record is discussed and compared with other holocene records they reveal periods of drought which occurred at 4 3 4 ka and around 3 5 ka with relatively wet phases between from 3 ka there is a general trend towards dryness as evidentiated by the relatively high 18o values of 3 5 to 2 5 recorded in speleothem spd 1 there is distinct trend of drying during the roman warm period and further toward the dark age cold period dacp with shorter periods of wetter conditions these changes coincide well with the other records thus revealing regional events along the eastern adriatic

sedimentological constraints on the late silurian history of the highland boundary fault scotland implications for midland valley basin development the relationship between movement on the highland boundary fault and deposition of the lower old red sandstone in the midland valley basin of scotland is controversial most models favour mid silurian to early devonian sinistral movement on the highland boundary fault and development of a transtensional midland valley basin to constrain highland boundary fault movement during the late silurian we examine the basal lower old red sandstone alluvial succession exposed adjacent to the highland boundary fault a lack of synsedimentary fault movement indicators coupled with an increase in stratal thickness across the fault indicates that the highland boundary fault was not active during lower old red sandstone sedimentation a transtensional basin model cannot be sustained

u th isotope systematics from the soreq cave israel and climatic correlations precise 230 th 234 u ages were obtained on thirty one growth laminae in speleothem samples which are self consistent with the detailed layer stratigraphy samples with low 232 th 238 u ratios give ages with analytical uncertainties of 40 years at 2 ky and 1000 years at 90 ky some growth zones with high but variable 232 th 238 u were dated by intermal isochrons this permits the determination of the initial 230 th 232 th assuming equilibrium of 232 th and 238 u series in the source of the high 232 th component this shows initial 230 th 232 th in activity units of from 1 3 to 2 9 the calculated atomic ratios of 232 th 238 u for the high 232 th component range from 1 08 to 2 4 which is well below the average crustal value speleothem materials with high 232 th 238 u are found to exhibit clear correlations of 232 th with si al and fe while 238 u correlates with sr and ba analyses of soreq cave drip waters show that the particulates in the waters have high 232 th concentrations and a 232 th 238 u ratio much lower than that found in the high 232 th component in speleothems but with 230 th 232 th 1 0 to 2 4 we infer that the trapped high th component in speleothems is from particulate matter in water with a large concentration of adsorbed u and not simply from detrital material the speleothems have only small234u excess the initial 234 u 238 u 0 show a range of 1 02 to 1 14 that was found to correlate with age over the past 25 ky the youngest samples have values in the same range as the modern drip waters there appears to be a correlation of 234 u 238 u 0 with the 18 o values there is a drop of 18 o in the time interval 20 to 15 ky which then remains relatively constant to recent times as the high 18 o values have been related to rainfall and associated climatic conditions we suggest that the 234 u 238 u in the speleothem reflects the effects of rainfall and soil weathering conditions on drip water composition and may provide a proxy for climate change