modification and preservation of environmental signals in speleothems speleothems are primarily studied in order to generate archives of climatic change and results have led to significant advances in identifying and dating major shifts in the climate system however the climatological meaning of many speleothem records cannot be interpreted unequivocally this is particularly so for more subtle shifts and shorter time periods but the use of multiple proxies and improving understanding of formation mechanisms offers a clear way forward

middle pleistocene bivalves of the iznik lake basin eastern marmara nw turkey and a new paleobiogeographical approach iznik lake is a tectonically originated basin mainly controlled by the e w trending middle strand of the north anatolian fault naf system pleistocene sediments occurring in front of the faults are well exposed both in the northern and in the southern shorelines of the basin in this study two endemic brackish water bivalve species didacna subpyramidata pravoslavkev 1939 and didacna nov sp were found in the oldest terrace of the northern pleistocene sequence having characterized morphology these species serve as stratigraphic indicators in the regional pleistocene stratigraphy of the ponto caspian region and thus are well correlated to the assemblages of the early khazarian subhorizon middle pleistocene hence these data demonstrate that the early khazarian brackish water sea covered the study area additionally a model for the formation of the basin is proposed the iznik lake basin was a gulf of the former marmara sea in the early khazarian connecting the marmara to the black sea and the caspian sea the subsequent regional prograding uplifts main dextral strike slip fault and many normal faults of the naf zone cut off the marine connections to the basin leading to its present location and topographic level

a terrestrial u th dated stable isotope record of the penultimate interglacial abstract here we present the first u series dated stable oxygen isotope record in continental europe that covers the entire tripartite penultimate interglacial i e marine isotope stages 7 5 to 7 1 this record was obtained from a u rich stalagmite from spannagel cave in the austrian alps which is largely devoid of kinetic isotope fractionation effects which comprised previously studied flowstone from this site composed of dense columnar calcite this speleothem apparently grew without significant interruption for ca 50 ka albeit at a very slow rate the age model was established based on 23 individual u th tims dates using a combination of a bayesian approach which includes additional information using stratigraphic constraints and the mixed effect regression model the resulting record shows three prominent maxima in 18 o mis 7 5 7 3 and 7 1 separated by a long earlier and a shorter later cold period mis 7 4 and 7 2 respectively the mid points of the transitions into the three warm phases occurred at 240 3 215 2 and 200 3 ka and the mis 7 6 transition was dated to 190 3 ka the timing of these climate transitions is supported by other samples from the same cave and agrees within analytical uncertainties with u th dated evidence from corals marine aragonitic sediments and submerged stalagmites as well as with orbitally tuned deep sea records good agreement was also found with new speleothem data from china as far as mis 7 1 and 7 5 are concerned whereas mis 7 3 apparently started earlier and mis 7 2 lasted longer than in the alps comparing the european speleothem data with antarctic ice cores reveals obvious differences in age the latter suggesting an earlier start and a generally shorter duration of the three warm episodes in essence this study underscores the great potential of speleothems as accurate and precise chronometers of pleistocene climate change and emphasizes the need for similar studies in other continents including submerged caves in order to improve the imperfect chronological framework of mis 7

u pb dating of a speleothem of quaternary age we demonstrate that u pb dating is a promising method for secondary carbonate materials of quaternary age and older by obtaining a 206pb 238u age for a speleothem with high u 10 g g 1 and very low pb 10 ng g 1 that is supported by an independent 230th age thermal ionisation mass spectrometry was used to determine the u and pb isotopic ratios and concentrations for subsamples of a stalactite from winnats head cave peak district uk we obtained 206pb 204pb ratios up to 50 and determined a 206pb 238u age of 248 10 ka which is within error of the 207pb 235u age of 333 79 ka and a spectrometric u th age of 255 ka for samples of tertiary and quaternary age the initial state of u series disequilibrium is an important consideration and as with most radiometric dating techniques the mineral must have remained closed to u th pb and all intermediate daughters we show that dense calcite speleothems are ideal in this respect and that no loss of rn has occurred unlike u series disequilibrium methods u pb dating has no upper limit and hence materials of quaternary age older than 0 6 ma can be analysed to investigate landscape development paleoclimate hominid evolution or hydrogeochemistry in carbonate terrains

trace element distribution in annual stalagmite laminae mapped by micrometer resolution x ray fluorescence implications for incorporation of environmentally significant species abstract stalagmite er78 from grotta di ernesto cave in ne italy displays clear annual lamination consistent with its shallow depth below a forest ecosystem subject to autumnal peaking of water infiltration synchrotron radiation scanning micro x ray fluorescence analyses of heavy elements at european synchrotron radiation facility beamline id22 and light elements at id21 with 1 3 m resolution has been combined with data from ion microprobe analyses to reveal chemical variability across the visible layers of these annual laminae a series of elements display a symmetrical peak centered around the thin dark layer at the top of each lamina the peak concentration is ordered y zn cu and pb p and br this hierarchy is thought to reflect the selectivity of transport of these elements possibly by organic colloids flushed from the soil zone during autumn infiltration ion microprobe analysis indicates na and f also increase as does h the latter reflecting increased microporosity sr displays a trough around the dark and thin autumn layer implying that its incorporation may be limited by competition with other elements mg and s show a different pattern of annual variation and fe displays none the trace metals br and y display peak abundance in the early 20th century which appears to reflect a period of tree felling rather than a climatic anomaly the results demonstrate the power of the high spatial resolution and low detection limits of the synchrotron technique and its ability to produce quantitative maps that allow distinction of layered structure from that of isolated particles or irregular inhomogeneities

climate caving in to new chronologies speleothems formed in caves such as stalagmites can be dated precisely and are increasingly providing detailed and accurate records of past climates

late glacial holocene palaeoceanography of the sea of marmara timing of connections with the mediterranean and the black seas abstract stratigraphic analysis of late quaternary sediments of the sea of marmara basin smb indicates that it was a freshwater lake during the late glacial to ca 12 000 yr bp depositing sediments with a neoeuxinian fauna characteristic of the black sea basin at ca 12 000 yr bp it was inundated by the mediterranean waters and gradually converted into a marine realm as indicated by the presence above the neoeuxinian sediments of a mixed layer containing both marine and freshwater fauna a sapropelic sediment layer was deposited between 10 600 and 6400 yr bp under suboxic bottom water conditions this layer roughly corresponds in time to s1 sapropel unit of the eastern mediterranean suggesting a common origin its presence in the smb therefore supports the hypothesis that a large influx of freshwaters from the black sea was an important factor in sapropel formation in the eastern mediterranean a second sapropelic layer formed in the smb during 4750 to 3200 yr bp the earliest known record of mediterranean water in the bosphorus is at ca 5300 yr bp suggesting a later marine inundation than the 7150 yr bp event suggested by ryan and co workers an abrupt drowning of black sea shelf at 7 5 kyr bp geo eco marina 2 proc int workshop on fluvial marine interactions mainas romania 1 7 october 1997 pp 115 125 and ryan w b f pitman iii w c major c o shimkus k moskalenko v jones j a dimitrov p gorur n sakinc m yuce h 1997b an abrupt drowning of black sea shelf mar geol 138 1997 119 126 this implies that either earlier marine connections with the black sea were through a different waterway or the earlier marine record in the strait has been eroded the present two layer flow system was established at 4000 yr bp

evidence of warm and humid interstadials in central europe during early mis 3 revealed by a multi proxy speleothem record abstract marine isotope stage 3 mis 3 57 27 ka was characterised by numerous rapid climate oscillations i e dansgaard oeschger d o events which are reflected in various climate archives so far mis 3 speleothem records from central europe have mainly been restricted to caves located beneath temperate alpine glaciers or close to the atlantic ocean thus mis 3 seemed to be too cold and dry to enable speleothem growth north of the alps in central europe here we present a new speleothem record from bunker cave germany which shows two distinct growth phases from 52 0 0 8 0 5 to 50 9 0 6 1 3 ka and 47 3 1 0 0 6 to 42 8 0 9 ka rejecting this hypothesis these two growth phases potentially correspond to the two warmest and most humid phases in central europe during mis 3 which is confirmed by pollen data from the nearby eifel the hiatus separating the two phases is associated with heinrich stadial 5 hs 5 although the growth stop precedes the onset of hs 5 the first growth phase is characterised by a fast growth rate and mg concentrations and sr isotope data suggest high infiltration and the presence of soil cover above the cave the second growth phase was characterised by drier but still favourable conditions for speleothem growth during this phase the 13c values show a significant decrease associated with d o event 12 the timing of this shift is in agreement with other mis 3 speleothem data from europe and greenland ice core data

direct radiometric age determination of carbonate diagenesis using u pb in secondary calcite abstract carbonate rocks and corals from the middle devonian lucas formation ontario have 238 u 204 pb values ranging from 132 to 559 and give concordant apparent 206 pb 238 u and 207 pb 235 u ages in approximate agreement with the primary age of sedimentation a carbonate rock from one part of the section gives an anomalously young age and contains patches of secondary calcite spar this spar is predominantly pale purple under cathodoluminescence cl and contains 250 600 ppb u and 15 22 ppb pb the values range from 2 10 3 10 4 making the pb very radiogenic apparent 206 pb 238 u ages range from 208 to 249 ma and 232 th 238 u values are from 0 005 to 0 040 the younger ages are correlated with an increase in orange cl and higher apparent values the age scatter is attributed to mixing of a subordinate calcite spar which infiltrated the older spar the young calcite is bright orange under cl has 7200 ppb u of 6 2 10 4 a of 0 23 and is dated at 45 ma the age of the older spar has been determined by a sequential dissolution technique the resulting u pb data can be plotted as u pb age spectra and yield lplateau dates ranging from 231 5 1 4 to 244 9 1 6 ma and an integrated 206 pb 238 u age of 238 2 1 1 ma also the sequential dissolution increases the values progressively to a5 10 4 making these ages independent of the initial pb correction the occurrence of two young ages of diagenetic calcite in these strata is consistent with the idea of recurrent fluid activity along fracture zones in subsurface sediments in the michigan basin this study shows that it is now possible to date secondary carbonate diagenesis by u pb and by inference to determine precisely the timing of activity on ancient fracture zones in carbonate rocks

seasonal variations in sr mg and p in modern speleothems grotta di ernesto italy sub annual variations in trace element chemistry and luminescence have recently been demonstrated from speleothems and offer the potential of high resolution palaeoclimatic proxies however no studies have yet examined microscopic trace element variations in relation to modern cave conditions in this study the spatial variations in trace element sr mg and p concentrations in speleothems a stalagmite and a soda straw stalactite from the alpine ernesto cave temperature 6 6 0 1 c in a forested catchment in ne italy have been studied using secondary ion mass spectrometry sims and compared with environmental parameters and waters in the modern cave an annual lamination exists in the stalagmite and soda straw stalactite in the form of clear calcite with narrow visible layers which are uv fluorescent and interpreted to contain soil derived humic fulvic acids washed into the cave during autumn rains microanalyses were undertaken of seven annual laminae probably deposited during the 1960s in the stalagmite and seven laminae in the 1990s for the stalactite the analysis results show that sr consistently has a trough and p a peak centred on the inclusion rich layer mg shows mainly a negative covariation with sr in laminae formed in the 1990s but a positive covariation in the stalagmite formed in 1960s the spatial scale of the main geochemical variations is the same as that of annual laminae of inclusion poor and inclusion rich couplets mass balance arguments are used to show that the p is inorganic in form and presumably occurs as individual phosphate ions within the calcite most drip waters show limited chemical variations but a summer peak in trace elements in 1995 and a decrease in mg ca in the following winter are notable more pronounced covariations in mg ca and sr ca are shown by a site with highly variable drip rates where ratios increase at slow drip rates the strongest seasonal variations are found in pool waters where ratios increase reflecting significant ca removal from the water into the calcite during the winter in response to seasonal pco2 variations in cave air thus the cave waters compositions tend to reflect climate conditions such that mg ca and sr ca are tentatively interpreted to be higher when climate conditions are dry combining results from the speleothems and cave water along with the behaviour of each trace species mg ca variations in the speleothems are considered to reflect their variation in the cave waters whereas sr incorporation is also dependent on precipitation rate in this case mainly controlled by temporal variations in pco2 in the cave and conceivably also by inhibitors such as phosphate p adsorption a fraction of which is subsequently incorporated within calcite depends on aqueous phosphate concentration and water flux both of which should increase during the autumn therefore multiple trace element profiles in speleothems reflect multiple aspects of environment seasonality and conditions and hence a calibration against weather records is desirable to establish their palaeoclimatological meaning the strong annual variation of trace elements and particularly p can provide chronological markers for high resolution studies of other climate proxies such as stable isotopes

carbonate deposits from the ancient aqueduct of beziers france a high resolution palaeoenvironmental archive for the roman empire abstract carbonate deposits from a roman aqueduct in beziers southern france record environmental conditions during the late first century c e these deposits formed in a steep section of the aqueduct with a high flow velocity which caused rapid deposition of up to 11 mm of calcite per year over a period of 22 24 years the microstructure trace element and stable isotope composition show that regular deposition was interrupted by high discharge events probably in response to heavy rainfall during autumn and winter transporting colloidally and particle bound elements and depositing calcite with elevated 18 o values individual autumn high discharge events coincide with abrupt decreases in 13 c from 8 to 12 giving rise to a saw tooth profile in some years several high flow events persisted throughout the winter suppressing this profile event horizons of micrite capping sparite growth surfaces enriched in mg may represent anomalously low water levels or periods when the channel fell dry in comparison to carbonate deposits from roman aqueducts in the eastern mediterranean visible layering is less regular and pronounced in beziers reflecting a more complex precipitation pattern

calcite and aragonite precipitation from seawater solutions of various salinities precipitation rates and overgrowth compositions abstract the reaction rate and composition of calcite and aragonite overgrowths precipitated from seawater solutions of various salinities i e s 5 15 25 35 44 were determined at 25 c and 10 2 5 atm co2 partial pressure using a constant disequilibrium seeded technique the rate data were fitted to an empirical rate law of the form log r n c or a 1 log k where n is the empirical reaction order and k is the rate constant calcite precipitation rates in seawater solutions do not vary appreciably as a result of salinity variations over the range investigated while those for aragonite show an increase in going from the higher i e s 35 44 to the lower i e s 5 15 25 salinity range this study also confirms previously published findings that above a given saturation state i e c 2 6 aragonite precipitates more rapidly than calcite at 25 c the incorporation of sr2 in aragonite and mg2 in calcite overgrowths are independent of the precipitation rate the partition coefficient of sr2 in aragonite is approximately equal to unity and is unaffected by salinity variations between 5 and 44 however the mg2 partition coefficient in calcite increases with decreasing salinity of the parent seawater solutions possibly as a result of variations in the sulfate content of the solutions and solids the experimental results were discussed in the context of a number of geological environments

revealing the pace of river landscape evolution during the quaternary recent developments in numerical dating methods during the last twenty years several technical developments have considerably intensified the use of numerical dating methods for the quaternary the study of fluvial archives has greatly benefited from these enhancements opening new dating horizons for a range of archives at distinct time scales and thereby providing new insights into previously unanswered questions in this contribution we separately present the state of the art of five numerical dating methods that are frequently used in the fluvial context radiocarbon luminescence electron spin resonance esr 230th u and terrestrial cosmogenic nuclides tcn dating we focus on the major recent developments for each technique that are most relevant for new dating applications in diverse fluvial environments and on explaining these for non specialists therefore essential information and precautions about sampling strategies in the field and or laboratory procedures are provided for each method new and important implications for chronological reconstructions of quaternary fluvial landscapes are discussed and where necessary exemplified by key case studies a clear statement of the current technical limitations of these methods is included and forthcoming developments which might possibly open new horizons for dating fluvial archives in the near future are summarised

trace elements in speleothems as recorders of environmental change speleothems are now established as important palaeoenvironmental archives and contain a number of suitable proxies although trace elements have been much less widely used than oxygen and carbon isotopes the complexity of the cave environment helps to explain this since the fluids from which speleothems form vary greatly in composition in space even within a cave chamber seasonally and over longer periods understanding the forcing factors for this variability is the key to decoding the significance of the trace element records a variety of techniques are available for trace element work and it is important to understand the strengths and limitations of each and also to seek an understanding e g by micro imaging techniques of whether the elements are associated with inclusions in the caco3 or are isolated within the crystal lattice for some elements there is a more or less predictable relationship between element ratios to ca in the water and in the calcite individual trace elements may be derived from atmospheric deposition superficial deposits or bedrock and can be recycled in soil processes before being transferred to the cave some components show an instantaneous response to water infiltration whereas others are only leached by slow flowing seepage waters changing in the proportion of water from fracture fed and seepage flow aquifer compartments is an important factor in influencing trace element supply high flows lead to higher fluxes of soil derived colloidally transported elements conversely under relatively dry conditions degassing of co2 results in prior calcite precipitation upflow of the site of speleothem deposition and leads to higher ratios of sr ca and mg ca some trace element variations in speleothems over time are induced during crystal growth whereby faster growth leads to a greater departure from equilibrium element partitioning despite the demonstrated temperature dependence of mg partitioning into calcite attempts at deriving palaeotemperature records from speleothems have been so far confounded by variations in solution mg ca and or crystallographic effects a number of case studies have effectively used trace elements such as speleothem mg as records of palaeo aridity using supporting arguments from modern monitoring or covariations with other parameters such as stable isotopes sr and u isotopes can also be indicators of palaeohydrology although sr isotope variations can also reflect varying aeolian input considerable progress has been made in decoding the meaning of annual trace element variations using criteria for understanding dripwater hydrology and ph this should lead in the future to more specific interpretations of how seasonality evolves through time

determination of aragonite trace element distribution coefficients from speleothem calcite aragonite transitions the processes that govern the incorporation of trace elements into speleothems can often be linked to environmental changes although element incorporation into speleothem calcite is now reasonably well understood current knowledge regarding trace element variability in speleothem aragonite is very limited of particular interest is whether trace element distribution coefficients are above or below one in order to assess the extent to which prior aragonite precipitation has affected speleothem aragonite trace element records this study uses nine calcite to aragonite transitions in seven speleothems from diverse environmental settings to derive the first quantitative estimates of the distribution coefficients for several elements in speleothem aragonite dmg ar 9 7e 5 9 01e 5 dba ar 0 91 0 88 dsr ar 1 38 0 53 and du ar 6 26 4 54 1 sd for one speleothem from western germany the distribution coefficients are generally higher which is potentially related to the very low growth rates 11 m year of this sample in particular dsr ar appears to show a negative correlation with growth rate when growth rate is below 20 m year in summary our results demonstrate that speleothem aragonite dmg ar is below one du ar is considerably above one and dsr ar is above one or close to unity for dba ar reaching a similar conclusion is difficult due to the relatively high uncertainty enhanced prior aragonite precipitation will thus result in lower u and higher mg concentrations in speleothem aragonite although in many cases mg in speleothem aragonite is most likely dominated by other processes this result suggests that u concentrations in aragonitic stalagmites could serve as a very effective proxy for palaeo rainfall

230th u dating of last interglacial brain corals from bonaire southern caribbean using bulk and theca wall material abstract we compared the suitability of two skeletal materials of the atlantic brain coral diploria strigosa for 230th u dating the commonly used bulk material comprising all skeletal elements and the denser theca wall material eight fossil corals of presumably last interglacial age from bonaire southern caribbean sea were investigated and several sub samples were dated from each coral for four corals both the ages and the activity ratios of the bulk material and theca wall agree within uncertainty three corals show significantly older ages for their bulk material than for their theca wall material as well as substantially elevated 232th content and 230th 238u ratios the bulk material samples of another coral show younger ages and lower 230th 238u ratios than the corresponding theca wall samples this coral also contains a considerable amount of 232th the application of the available open system models developed to account for post depositional diagenetic effects in corals shows that none of the models can successfully be applied to the bonaire corals the most likely explanation for this observation is that the assumptions of the models are not fulfilled by our data set comparison of the theca wall and bulk material data enables us to obtain information about the open system processes that affected the corals the corals showing apparently older ages for their bulk material were probably affected by contamination with a secondary detrital phase the most likely source of the detrital material is carbonate sand the higher 230th 232th ratio of this material implies that detrital contamination would have a much stronger impact on the ages than a contaminant with a bulk earth 230th 232th ratio and that the threshold for the commonly applied 232th reliability criterion would be much lower than the generally used value of 1 ng g 1 the coral showing apparently younger ages for its bulk material was probably influenced by more than one diagenetic process a potential scenario is a combination of detrital contamination and u addition by secondary pore infillings our results show that the dense theca wall material of d strigosa is generally less affected by post depositional open system behaviour and better suited for 230th u dating than the bulk material this is also obvious from the fact that all ages of theca wall material reflect a last interglacial origin 125 ka whereas the bulk material samples are either substantially older or younger however for some corals the 230th u ages and activity ratios of the bulk material and the theca wall samples are similar this shows that strictly reliable 230th u ages can also be obtained from bulk material samples of exceptionally well preserved corals however the bulk material samples more frequently show elevated activity ratios and ages than the corresponding theca wall samples our findings should be generally applicable to brain corals mussidae that are found in tropical oceans worldwide and may enable reliable 230th u dating of fossil corals with similar skeletal architecture even if their bulk skeleton is altered by diagenesis the 230th u ages we consider reliable 120 130 ka along with a recently published age of 118 ka provide the first comprehensive dating of the elevated lower reef terrace at bonaire 118 130 ka which is in agreement in timing and duration with other last interglacial records

hydrogeochemistry and fractionation pathways of mg isotopes in a continental weathering system lessons from field experiments abstract the potential of magnesium isotope records from cave carbonate archives speleothems has been documented but remains underexplored this is due to the limited knowledge regarding the complex suite of physico chemical and biological disequilibrium fractionation processes affecting meteoric fluids in the soil zone the carbonate hostrock and calcite precipitation in the cave this study presents 26 mg data from a monitored cave in germany bunker cave including rain water 26 mg 0 70 0 14 soil water 26 mg 0 51 0 10 and drip waters 26 mg 1 65 0 08 sampled between november 2009 and may 2011 field precipitation experiments i e calcite precipitated on watch glasses 26 mg 3 56 0 26 may 2006 to june 2010 were found to be of limited use this is because of experimental crystallographic and sampling artefacts conversely variations in soil and drip water 26 mg over time are predominantly related to seasonal variations in water availability and air temperature affecting the subtle weathering ratio between mg bearing clay minerals in the soil here mainly chlorite and montmorillonite and the low mg calcite hostrock bunker cave 26 mg drip water values display a significant dependency on the air temperature outside the cave this is because air temperature influences co 2 levels in the soil and hence rock water interaction for fast drip sites the direct correlation of 26 mg soil water and 26 mg drip water documents a relative short residence time of the fluid in the carbonate aquifer and thus limited isotope equilibration and mixing of different reservoirs this result is encouraging and adds new evidence to the poorly understood hydro geochemistry of carbonate aquifers slow seepage flow drip sites display an annual 26 mg drip water pattern that is geochemically unrelated to that of the soil water further research including laboratory experiments must focus on the complex fractionation between drip water and speleothem calcite mg isotope record

the timing and evolution of the post glacial transgression across the sea of marmara shelf south of istanbul high resolution reflection seismic profiles with core analyses of sedimentary sequence near the sea of marmara som entrance to the strait of istanbul soi bosphorus provide detailed record of sealevel changes since the late glacial maximum lgm the sequence is deposited over the lgm erosional surface at a maximum depth of 105 m it includes seven seismic units that can be confidently correlated with 14c dated sedimentary units in the cores unit 6 represents levee deposits of the paleo soi channel that was deposited by a black sea outflow during 11 2 10 6 kyr bp the reflection surfaces at base of unit 5 and 4 correspond to wave cut terraces at 71and 63 m respectively and are estimated to be 10 6 and 9 8 kyr bp the seismic unit 2 overlaying a mud drape unit 3 comprises deltaic sediments that was deposited during 6 400 3200 yr 14c bp isopach map and

a post younger dryas black sea regression identified from sequence stratigraphy correlated to core analysis and dating the north western black sea shelf is the widest continental shelf of the black sea where the danube delta prodelta system includes important records on the black sea water level fluctuations this study integrates newly acquired high resolution single channel seismic reflection profiles and calypso piston cores recovered along a transect extending from the danube delta deep into its deep sea fan the correlated results provide information on the late quaternary architecture of the danube black sea shelf and on the role of global glacio eustatic fluctuations on the building of the danube delta prodelta the sedimentary sequences in the black sea are strongly affected by water level changes for the whole duration of late glacial holocene period the level of the black sea was controlled by the regional climate modifications rather than the global eustatic changes the seismic sequences recognized on a very high resolution seismic profile were dated by two calypso piston cores based on the obtained data during the last glacial maximum the black sea was a land locked lake with the level below 120 m in the course of the deglaciation the lake level rose up to 40 m which is confirmed by occurrence of the prodelta lobes formed after the rise in water level originated from the melt water following the younger dryas 11 000 8500 c 14 bp there occurred a new level lowering to the level of 100 m identified by the forced regression deposits recorded on the romanian shelf this last lowstand previously recognized by a pronounced shoreline with a characteristic beach profile and a belt of coastal dunes is also indicated by the prodelta at 100 m depth all these coastal features as well as the incised anastomosed channel system remained preserved on the shelf resulting from a rapid ultimate transgression starting immediately after 8500 c 14 bp c 2010 elsevier ltd and inqua all rights reserved

tracing the transport of anthropogenic lead in the atmosphere and in soils using isotopic ratios the isotopic composition of lead in aerosols and soils in israel is used to characterize the sources of anthropogenic lead in the region to ascertain the isotopic composition of natural rock derived lead in specific areas and to determine rates of anthropogenic lead migration in soils the isotopic composition of lead currently emitted from cars in israel 206pb207pb 1 115 2 is controlled by alkyl lead produced in france and germany in addition to petrol lead two more sources of anthropogenic lead can be detected in sampled aerosols the first one has low concentrations of lead 4 ng m3 and 206pb207pb 1 157 and is most likely lead emitted in turkey that traveled across the eastern mediterranean basin the second type of aerosols contains a mixture of lead emitted in several countries including turkey greece and ukraine 206pb207pb value of 1 155 1 160 pb 20 30 ng m3 anthropogenic lead is more accessible for acid leaching than natural lead therefore it is more labile in the soil the isotopic composition of lead in the acid leached fraction of near road soil profiles record the histor of alkyl lead emission in the country based on changes in the isotopic composition of lead with soil depth it is estimated that anthropogenic lead migrates into the soil at approximately 0 5 cm y a soil profile from a relatively remote area is less contaminated by anthropogenic lead and displays a different distribution of lead isotopic values with depth the isotopic composition of lead suggests that natural lead in soils developed on carbonate bedrock is derived from clays either from the rock esidue the clay fraction in the carbonate bedrock or from airborne clay but not from lead released from the carbonate fraction in the rock

precise dating of dansgaard oeschger climate oscillations in western europe from stalagmite data the signature of dansgaard oeschger events millennial scale abrupt climate oscillations during the last glacial period is well established in ice cores and marine records but the effects of such events in continental settings are not as clear and their absolute chronology is uncertain beyond the limit of 14 c dating and annual layer counting for marine records and ice cores respectively here we present carbon and oxygen isotope records from a stalagmite collected in southwest france which have been precisely dated using 234u 230th ratios we find rapid climate oscillations coincident with the established dansgaard oeschger events between 83 000 and 32 000 years ago in both isotope records the oxygen isotope signature is similar to a record from soreq cave israel and deep sea records indicating the large spatial scale of the climate oscillations the signal in the carbon isotopes gives evidence of drastic and rapid vegetation changes in western europe an important site in human cultural evolution we also find evidence for a long phase of extremely cold climate in southwest france between 61 2 0 6 and 67 4 0 9 kyr ago

an abrupt drowning of the black sea shelf abstract during latest quaternary glaciation the black sea became a giant freshwater lake the surface of this lake drew down to levels more than 100 m below its outlet when the mediterranean rose to the bosporus sill at 7 150 yr bp 1 saltwater poured through this spillway to refill the lake and submerge catastrophically more than 100 000 km2 of its exposed continental shelf the permanent drowning of a vast terrestrial landscape may possibly have accelerated the dispersal of early neolithic foragers and farmers into the interior of europe at that time

accurate trace element analysis of speleothems and biogenic calcium carbonates by la icp ms the high spatial resolution of laser ablation inductively coupled plasma mass spectrometry la icp ms microanalysis of speleothems and biogenic calcium carbonates makes it possible to improve our understanding of past climatic conditions however there are analytical problems associated with this method such as molecular interferences elemental fractionation and mass load dependent matrix effects when using nist silicate reference glasses for calibration our study with a sector field icp ms shows that many masses are affected by interferences such as 24mg by 48ca or 31p by 15n16o elemental fractionation and mass load dependent matrix effects have been detected for both 213 and 193 nm nd yag lasers they are small for refractory lithophile elements in particular for the 193 nm laser 5 for chalcophile siderophile trace elements with low boiling points however these effects are large up to 40 and 20 for the 213 and 193 nm lasers respectively and variable for the nist glasses and carbonates in this paper a protocol for precise and accurate la icp ms analysis of calcium carbonates is established isotopes for interference free measurements at low m m 300 and medium m m 4000 mass resolution have been identified the nist glasses are suitable for calibration of refractory lithophile element concentrations however matrix matched calibration with carbonate reference materials such as usgs macs 1 or macs 3 is necessary for accurate analysis of chalcophile siderophile elements with low boiling points analytical reproducibility rsd is a factor of 2 better using the 193 nm laser than the 213 nm laser as shown by the analysis of macs 1 and macs 3 la icp ms analyses yield results that agree with the reference values within relative uncertainties of ca 5 10 at the 95 confidence level we have applied la icp ms for the determination of trace element concentrations in calcite and aragonite layers of a stalagmite and found large variations for mg zn sr and u in ostracod shells the concentrations of some trace elements e g sr and ba vary significantly indicating the potential for paleoclimate research

aeolian contribution to strontium and strontium isotope variations in a tasmanian speleothem abstract a speleothem from south central tasmania shows marked secular variations in its strontium content the element exhibits a striking bimodal distribution pattern with abrupt changes between two modal groups that is believed to be due to rapid changes in the direction of the dominant strong winds strontium isotope compositions in the speleothem range from 0 70865 to 0 70898 indicating derivation of sr from at least two distinct sources the first a persistent one from the overlying limestone the second a higher 87 sr 86 sr component probably representing input from terrestrial dust the speleothem record is unusual because it indicates a greater input of radiogenic sr dust flux during interstadial times than under full glacial conditions if an aeolian origin of some of the strontium contained in speleothems at other inland cave sites around the world can be confirmed variations in strontium isotope composition will provide high resolution records of how terrestrial dust flux has varied during the quaternary in near coastal sites significant amounts of strontium may be derived from seasalt and in those areas temporal variation of the element in speleothems may reflect at least in part changing distance from the coast due to changes in sealevel

a paleoclimate record of the last 17 600 years in stalagmites from the b7 cave sauerland germany abstract petrographical and geochemical parameters of stalagmites from the b7 cave in iserlohn letmathe northern rhenish massif nw germany record late and postglacial climate changes temperature and or precipitation fabrics and microfacies of the stalagmite profiles lead to a differentiation of four hierarchies of rhythms clastic layers in the stalagmites are caused by flooding events and are time markers twenty four tims th u age dates provide a time calibration of stalagmite growth phases one stalagmite reveals an early growth period between 17 6 and 16 7 ka bp between 9 6 and 5 5 ka bp atlantic episode of the holocene the growth rate of the stalagmites was higher than before and after this time with dominant light porous microfacial laminae and high 18 o and 13 c values representing partly kinetic fractionation effects this part of the holocene is interpreted as a mainly warm episode with frequent interruptions of dripping within the past 4 ka the profiles with predominant dark compact facies reveal low isotopic values which may be interpreted as a temperature proxy record the stalagmite records resemble records from an irish stalagmite correlation with the 14 c record from european tree rings suggests that colder periods in the north atlantic were accompanied by drier winters in central europe

geochemistry of speleothem records from southern illinois development of 234u 238u as a proxy for paleoprecipitation natural waters universally show fractionation of uranium series u series parent daughter pairs with the disequilibrium between 234 u and 238 u 234 u 238 u commonly used as a tracer of groundwater flow because speleothems provide a temporal record of geochemical variations in groundwater precipitating calcite 234 u 238 u variations in speleothems provide a unique method of investigating water rock interaction processes over millennium time scales we present high precision thermal ionization mass spectrometric tims u series analyses of speleothems and drip waters from fogelpole cave in southern illinois data from all speleothems from the cave show an inverse correlation between 234 u 238 u and u concentration following the pattern observed in groundwaters globally within a 65 cm long stalagmite concordant 234 u 238 u 230 th and 235 u 231 pa ages for 5 samples indicate accurate chronology from 78 5 ka to 30 ka notably 234 u 238 u o which differs from most speleothems by having 234 u 238 u ob1 positively correlates with speleothem growth rate we generalize this to the observation that speleothems globally show 234 u 238 u o deviating farther from secular equilibrium at lower growth rates and approaching secular equilibrium at higher grow rates based on the fogelpole observations we suggest that groundwater 234 u 238 u is controlled by the u oxidation state the u concentration of the water and the fluid velocity a transport model whereby u series nuclides react and exchange with mineral surfaces can reproduce the observed trend between growth rate and 234 u 238 u o based on this result we suggest that 234 u 238 u o in speleothems may record changes in hydrologic flux with time and thus could provide a useful proxy for long term records of

high resolution seismic profiling in the sea of marmara northwest turkey late quaternary sedimentation and sea level changes high resolution sparker seismic profiling was carried out in the sea of marmara northwest turkey to study the late quaternary tectonics and sedimentation of this important active basin at the western end of the north anatolian fault zone a sedimentary unit interpreted as the clinoforms of a prograding delta was observed in places along the outer part of the southern shelf the topset foreset transitions of the latest clinoforms cluster around 100 m below present sea level they were probably deposited during the last glacial maximum and early phase of deglaciation between 25 and 13 k y b p when the level of the aegean was below that of the dardanelles sill 60 70 m below sea level at present therefore the sea of marmara was isolated from the aegean during the last glacial maximum but it is possible that a fluvial overflow existed across the dardanelles during this time stabilizing the level of the marmara lake and allowing the delta progradation rivers that drain into the sea of marmara from the south have a much greater combined drainage basin area and sediment flux than those draining the region to the north this may explain the much broader shelf to the south half graben bounded by north dipping normal faults observed within the southern shelf would tend to trap sediment sourced from the south and subdue any sea bed morphology on the shelf

intra and inter annual uranium concentration variability in a belizean stalagmite controlled by prior aragonite precipitation a new tool for reconstructing hydro climate using aragonitic speleothems aragonitic speleothems are increasingly utilised as palaeoclimate archives due to their amenability to high precision u th dating proxy records from fast growing aragonitic stalagmites precisely dated to annual timescales can allow investigation of climatic events occurring on annual or even sub annual timescales with minimal chronological uncertainty however the behaviour of many trace elements such as uranium in aragonitic speleothems has not thus far been as well constrained as in calcitic speleothems here we use uranium concentration shifts measured across primary calcite to aragonite mineralogical transitions in speleothems to calculate the distribution coefficient of uranium in aragonitic speleothems derived du 3 74 1 13 because our calculated du is considerably above 1 increased prior aragonite precipitation due to increased karst water residence time should strongly control stalagmite aragonite u ca values consequently uranium concentrations in aragonitic speleothems should act as excellent proxies for effective rainfall we test this using a high resolution icp ms derived trace element dataset from a belizean stalagmite yok g is an aragonitic stalagmite from yok balum cave in belize with an extremely robust monthly resolved chronology built using annual 13c cycles we interpret seasonal u ca variations in yok g as reflecting changes in the amount and seasonality of prior aragonite precipitation driven by variable rainfall amounts the u ca record strongly suggests that modern drying has occurred in belize and that this drying was primarily caused by a reduction in wet season rainfall this is consistent with published stable isotope data from yok g also very strongly suggesting modern rainfall reductions previously interpreted as the result of southward itcz displacement our results strongly suggest that u ca values in aragonitic speleothems are excellent proxies for rainfall variability this new tool combined with the exceptional chronological control characteristic of aragonitic stalagmites and the high spatial resolution afforded by modern microanalytical techniques should facilitate the construction of new exquisitely resolved rainfall records providing rare insights into seasonality changes as well as long term changes in local recharge conditions

speleothem δ13c record suggests enhanced spring summer drought in south eastern spain between 9 7 and 7 8 ka a circum western mediterranean anomaly south eastern spain is one of the driest regions in europe and thus prone to drought terrestrial climate records covering the late glacial and holocene from this area are sparse here we present

periglacial transport distance of pb derived from small scale ore veins in the rhenish slate mountains abstract the spatial extent of metal contamination caused by small scale ore veins is increased by periglacial solifluction our objectives were 1 to examine the spatial distribution of pb in cover beds that migrated over pb ore veins 2 to calculate the transport distance of ore derived pb and 3 to determine controls on the transport distance we examined six transects 320 775 m long in the rhenish slate mountains in west germany the transects included four west exposed and two east exposed slopes with inclinations between 2 20 all transects were forest covered and located at 280 450 m above sea level soils were dystric cambisols and stagnic luvisols samples of 120 b horizons developed in the sediments of the last ice age wuerm were analyzed for total pb concentrations and partly also 206 pb 207 pb ratios the pb concentrations ranged from 20 to 135 mg kg 1 the spatial pb distribution suggested that 14 out of 18 sampling points showing local pb concentration maxima contained pb from ore veins upslope with a two end member mixing model using 206 pb 207 pb isotope ratios of the ore 206 pb 207 pb ratio 1 1828 as one end member and of the native substrate a mixture of slate and loess 206 pb 207 pb ratio 1 2254 0 0072 as the other we confirmed that the 14 pb peaks originated from the ore because they contained 76 100 of ore derived pb by the use of a geographic information system the transport distance of this pb was determined to range between 30 and 110 m silt concentrations pearson r 0 69 and the relief curvature cramer s v 0 60 were major controls on the transport distance our study demonstrates that pb ore veins can increase native soil pb concentrations in soil derived from the periglacial drift of the last ice age wuerm up to a distance of more than 100 m

postglacial connection of the black sea to the mediterranean and its relation to the timing of sapropel formation the opening of the connection between the mediterranean and black seas as sea level rose above the bosporus sill has long been associated with the formation of the most recent holocene sapropel deposit s1 in the eastern mediterranean but the mechanism has remained elusive we present a model for the opening of the black sea based on hydraulics arguments which demonstrates that increased freshwater flux out of the black sea began 500 1000 years after sea level reached sill depth and that the timescale for the increased freshwater flux that drained the freshwater reservoir of the black sea is about 2500 3500 years we argue that the increased freshwater discharge out of the black sea would lead to decreased deep water formation and higher productivity in the surface waters in the eastern mediterranean two conditions generally associated with sapropel formation the delay in increased freshwater flux after the opening of the black sea and the period of increased freshwater discharge appear to match the onset and duration of sapropel deposits in the eastern mediterranean

lead isotope systematics of epigenetic lead zinc mineralization in the western part of the rheinisches schiefergebirge germany in the western part of the rheinisches schiefergebirge three different types of epigenetic lead zinc vein mineralization in paleozoic rocks can be distinguished 1 syntectonic variscan veins 2 post variscan saxonian veins mainly in paleozoic siliceous clastic rocks 3 post variscan carbonate hosted mineralization in the aachen stolberg area ore impregnations occur in the triassic buntsandstein bunter sandstone and muschelkalk of the maubach mechernich triangular depression covering the paleozoic rocks data points define two distinct populations in both lead isotope diagrams and thus indicate two major variscan and post variscan mineralization events the lead isotope pattern of the paleozoic sedimentary rocks bears good evidence that this thick rock sequence may be the main source of metals for the mineralization the metals were mobilized at deeper levels by saline fluids at different times there are no direct indications for remobilization of the older variscan vein ore deposits the sandstone and carbonate hosted ore impregnations of maubach mechernich have a similar lead isotope pattern to the post variscan mineralization in the paleozoic sedimentary basement

caribbean hydroclimate and vegetation history across the last glacial period abstract we present a new speleothem trace element and stable isotope record which extends previous paleoclimate evidence from cuban speleothems to the last 96 ka multiple proxies were used to reconstruct caribbean hydroclimate and vegetation variability on orbital to millennial timescales in particular our proxies indicate a shift to more abundant c4 compared to c3 vegetation and or reduced soil activity during the last glacial maximum our results confirm the close link of caribbean precipitation to north atlantic climate variability insolation and the strength of the amoc the associated variations in caribbean ssts and the shift of the itcz led to substantial changes of the hydrological cycle during heinrich stadials and the younger dryas climatic conditions in cuba were comparably cool and or dry in contrast warm dansgaard oeschger cycles were accompanied by wetter conditions this is in agreement with previous evidence for the holocene when north atlantic cold warm events coincided with drier wetter conditions in cuba however our record suggests that this connection was less dominant during mis 4 to 2 displayed by a weaker response of cuban precipitation proxies to north atlantic climatic shifts than during mis 5 in particular we hypothesize that this weaker connection was mediated by the southerly shifted itcz inducing a weakening of the northern branch of the caribbean low level jet which usually transports moisture into the northern caribbean this is strikingly evident during the deglacial when driest and or coolest conditions prevailed in western cuba from hs 1 into the younger dryas including the bolling allerod interstadial

ree3 and mn2 activated cathodoluminescence in lateglacial and holocene stalagmites of central europe evidence for climatic processes combined visual cathodoluminescence cl and spectral analyses of cl reveals periodic enrichments of rare earth elements ree3 and manganese mn2 within the laminations of eight calcitic lateglacial to postglacial stalagmites in the annual layers the enrichment of trace elements can be correlated with the autumn winter laminae which are strongly pigmented and rich in organic carbon during the holocene they occur especially in the atlantic stage and in subrecent recent times the enrichment of ree3 and mn reflects times of more intense weathering which presumably prevailed during the atlantic warm and humid climate in subrecent recent times especially the last 100 years these enrichments may have been at least partially anthropogenically induced

monitoring bunker cave nw germany a prerequisite to interpret geochemical proxy data of speleothems from this site summary monitoring cave environments is important to understand processes in karst systems if stalagmites from a specific cave are used as archives of past climate variability a quantitative understanding of the soil karst speleothem system is crucial the monitoring program performed in bunker cave nw germany which includes monthly collection of climatological data as well as air and water samples from the cave and the overlying soil since 2006 is a prerequisite for the interpretation of speleothem data from the cave in terms of climate variability the results show that bunker cave is a homogeneously ventilated cave with rather low pco2 values of 580 1200 ppmv which lacks strong seasonal variations the 18o value of cave drip water reflects the mean annual composition of the rain water and the seasonal variability is strongly attenuated indicating a well mixed karst aquifer hence stalagmites from bunker cave should be well suited to record interannual decadal climate trends seven drip sites in two cave chambers show three different types of discharge behaviour including slow seasonal drip fast seasonal drip and seepage flow the drip rate patterns of most drip sites are consistent with the main infiltration events taking into account a delay of several months an instantaneous response to precipitation i e piston flow is not observed for any drip site indicating a specific water capacity threshold in the soil karst aquifer prior calcite precipitation pcp was also identified especially during times of low discharge though pcp is not as pronounced at bunker cave as in other caves it probably has an influence on the mg ca ratios of the stalagmites

a pleistocene landslide dammed lake indicated by karren features eastern alps austria abstract numerous enigmatic tube shaped holes in the limestone ceilings of overhangs and small caves in a restricted area north of the village st aegyd am neuwalde lower austria have been known at least since 1933 but so far no detailed study concerning their origin has been conducted the vertical holes occur in middle triassic limestone and they are almost perfect cylinders tapering gently to a rounded apex their diameters are up to 5 5 cm and their depths reach 45 cm they occur on both sides of the unrechttraisen valley located in the north eastern part of the northern calcareous alps almost identical features were described from the shores of lakes in western ireland and termed rohrenkarren or tube karren simms 2002 according to simms model they have formed by condensation corrosion within air pockets trapped in limestone overhangs by rising water levels during floods the occurrence of these features is surprising because presently there is no lake and so far no palaeolake has been known from this area based on high resolution airborne laser scanning data and detailed field observations a landslide deposit was identified in a narrow section of the valley downstream of the rohrenkarren sites fine grained partly laminated sediments with abundant dragonfly anisoptera or flatworm turbellaria eggs indicative of lacustrine sediments up to ca 100 m above present river bed these data indicate that a landslide had dammed the unrechttraisen river resulting in a ca 100 m deep lake the rohrenkarren have formed due to fluctuations of the lake level resulting from differences in river run off and seepage through the landslide dam since 230th u dating of calcite crusts covering some rohrenkarren was not successful the age is not well constrained

comparison of high resolution sub annual records of trace elements in a modern 1911 1992 speleothem with instrumental climate data from southwest australia high spatial resolution measurements of mg p u sr ba and na using 193 nm excimer laser ablation inductively coupled plasma mass spectrometry has revealed clearly resolvable annual cycles in a modern speleothem from southwestern australia the age of this stalagmite is established by the dates of emplacement and removal of the boardwalk where it grew 1911 1992 this chronological constraint allows for the first confident comparison between the instrumental climate record and speleothem trace element content eleven laser ablation transects across a 0 5 mm wide section of the speleothem growth axis were measured cycles that could be matched between adjacent transects were stacked into a master record to minimise variability between tracks and permit greater confidence in comparing the trace elements to the instrumental climate record p and u positively and mg inversely mimic the sudden 20 decrease in annual rainfall experienced by this region since 1965 we argue that p from seasonal vegetation decay is transported to the speleothem before it is mineralised in the soil owing to the low p retention capacity of southwest australian soils both vegetation activity and the transport of vegetation derived hpo42 are sensitive to rainfall groundwater p concentration may also influence the transport of u through the strong affinity between phosphate and uranyl ions mg appears to be sensitive to groundwater residence time as this affects drip water mg ca composition by preferential loss of ca during drier episodes when calcite precipitates before reaching the stalagmite the effects of groundwater residence time may also be important for sr on inter annual scales however the behaviour of sr on the annual cycle is opposite to mg but compatible with ba and na which are shown to depend on speleothem growth rate

is the abrupt drowning of the black sea shelf at 7150yrbp a myth abstract sedimentological and chronostratigraphic studies of the coastal plain sediments of the black sea near the sakarya river turkey and seismic stratigraphic survey of the shelf sediments off this river s mouth were carried out the results indicate that just prior to its flooding by the mediterranean waters at about 7200 yr bp the black sea was a fresh water lake emptying its waters into the sea of marmara the water level of this lake was about 18 m lower than the present sea level but above the 35 m sill depth of the bosphorus this finding contradicts with ryan et al 1997a ryan et al 1997b hypothesis that the black sea lake water level was more than 100 m below the sill depth of the bosphorus and that the drowning of the black sea shelf at 7150 yr bp was abrupt

lead isotopes as tracers of pollutants in soils in order to gain insight into pb pollution of soils a pb isotope study was performed on soil profiles from selected sites in switzerland samples were analysed from the swiss national park where high pb contents have been observed despite the absence of obvious pollution sources other samples were taken in populated areas n of zurich where soil pollution was expected major goals of this study were 1 to distinguish anthropogenic from natural pollution by pb isotopic means 2 to determine the magnitude of pollution penetration 3 to assess the extent of pollution and 4 to identify the anthropogenic sources of pollution for major pollutants the pb isotopic compositions have been determined on samples collected between 1993 and 1995 fly ash from waste incinerators showed a constant isotopic composition 206pb 204pb 17 92 17 96 independent of the plant and sampling year in contrast samples representative for petrol pb displayed a larger spread 17 13 17 52 but generally had the least radiogenic composition among the pollutants sewage sludge showed an intermediate composition 17 74 17 88 aerosols as omnipresent pollutants had compositions 17 49 17 77 between car exhausts and fly ash from waste incineration reflecting their mixed nature for air fall deposition a mean pb isotopic composition 206pb 204pb 17 99 has been calculated for the 20th century taking into account the time dependent evolution of aerosols due to the pb isotopic contrast between unpolluted soil 206pb 204pb 18 8 and the anthropogenic contaminants pollution could be detected in all but one soil profile penetration of pollution reached to depths of between 20 and 30 cm calculated anthropogenic net pb inputs amounted to approximately 2 2 g m 2 in weakly polluted soils national park and reached values of 15 7 17 5 g m 2 in soils closely exposed to pollutants in soils with low anthropogenic pb inputs pollution could be explained by air fall deposition in stronger polluted soil profiles the pb isotopic composition of the pollutant did not allow us to clearly identify the pollution sources because of anthropogenic inputs from several sources

evolutionary mechanisms of the paratethys sea and its separation into the black sea and caspian sea abstract a possible mechanism leading to the transformation of the paratethys seas i e the sarmatian sea lake meotian sea pontian sea lake etc is here proposed the time period from the formation of the closed sarmatian sea lake to the present is also considered it will be shown that the main reason for the collapse of the sarmatian sea lake into the black and caspian seas was development of a canyon that cut through the mountains separating the black and mediterranean seas later this canyon was transformed into the bosporus and the dardanelles straits the canyon was formed mainly by erosive activity of a river that had periodically emerged from the paratethys abrasion of the canyon bottom and the related erosional lowering of its level led to gradual drainage of the paratethys basins the consequences of the messinian salinity crisis in the mediterranean sea contributed to the penetration of salt water into the paratethys and then to its temporary isolation and transformation into a closed sea lake later its level rose and the river was formed again that river flowed into the mediterranean sea in the process eroding its own bed during low levels of the world ocean the riverbed experienced increased erosion eventually dropping below high ocean level at which time the river was flooded by mediterranean water this process led to the formation of a corridor linking the seas together this corridor developed over the course of many glacioeustatic fluctuations in the world ocean

diagenesis of speleothems and its effect on the accuracy of 230th u ages abstract speleothems can be precisely dated by u series disequilibrium methods one basic assumption of the 230th u dating method is that the system remains closed and u and th isotopes are neither lost nor added after deposition for stalagmites this requirement is usually fulfilled due to their protected environment in caves however undersaturated drip water may lead to diagenesis of speleothem caco3 and altered 230th u ages here we present a detailed petrographic investigation using thin sections and 230th u ages of a stalagmite from the riesenberghohle northern germany which grew during marine isotope stages 5e c and a the occurrence of a mosaic fabric in large parts of the stalagmite in combination with several age inversions is a clear indication for diagenetic alteration we discuss the potential diagenetic processes and quantitatively model their influence on the 230th u ages post depositional u loss leads to increasing 230th 238u activity ratios and thus apparently older ages in contrast post depositional addition of u results in decreased 230th 238u activity ratios and apparently younger ages comparison with our modelling results suggests that diagenesis occurred early after deposition initial and post depositional detrital contamination probably played a minor role for the observed age inversions

geochemical paleogradient in pore waters controlled by aom recorded in an oligocene laminated limestone from the outer carpathians abstract a 20 cm thick laminated limestone of oligocene age from the outer carpathians is composed mainly of coccoliths and authigenic calcite 13 c values unequivocally indicate that the authigenic calcite precipitated as a result of methane oxidation the 13 c and 18 o values change gradually from the base to the top of the bed from 38 0 to 17 6 and from 1 1 to 5 7 respectively this trend reflects a geochemical gradient which developed in the zone of anaerobic oxidation of methane aom due to the consumption of sulfate by methane this gradient was related to an inverse relationship between the concentrations of both compounds in the pore waters of the aom zone methane was the source of isotopically light carbon it was accompanied by heavy oxygen containing water liberated from decomposition of gas hydrates the methane bearing fluids migrated upwards to the base of the sulfate reduction sr zone where methane was oxidized ch 4 so 4 2 hco 3 hs h 2 o and the aom zone developed the bicarbonate produced in this reaction was significantly depleted in 13 c and 16 o in the sr zone organic matter was oxidized by sulfate 2ch 2 o so 4 2 h 2 s 2hco 3 the bicarbonate released in that reaction was the source of isotopically heavier c and lighter o the proportion of bicarbonate produced by oxidation of methane to bicarbonate produced by oxidation of organic matter decreased upwards the resultant isotopic composition of bicarbonate dissolved in the pore waters changed upwards towards higher 13 c and lower 18 o values and has been recorded in the limestone s isotopic composition

isotopic archives of sulphate in speleothems the hemispheric impact of industrial emissions upon atmospheric sulphur loading is reflected in the sulphur depositional history recorded in cores from ice sheets however these do not reveal regional variations recently deposited speleothems are used here as archives of regional sulphur depositional history at two locations within the united kingdom and ireland 34s so4 and 18o so4 present within speleothem carbonate are measured for the first time as part of a dual isotope approach to decode the speleothem sulphur record the largely refractory nature of 34s so4 under oxidising conditions enables source provenance of atmospheric so2 whereas the complex cycles of isotopic exchange and fractionation during incorporation of oxygen into sulphate molecules enable 18o so4 signatures to yield insights into ambient environmental conditions and biogeochemical cycling in the ecosystem above the cave 34s so4 values extracted from speleothem carbonate formed within browns folly mine uk range from 3 5 to 5 5 and 18o so4 10 3 to 13 7 both signatures lie within the range expected from sulphate deposition in industrial locations and reflect the transfer of sulphate into speleothem calcite with little fractionation however 18o so4 signatures at crag cave western ireland are isotopically heavier than expected and approach isotopic equilibrium with 18o h2o under reducing conditions dual isotope analysis of 34s so4 and 18o so4 optimises the correct identification of sulphur sources and biogeochemical cycling prior to incorporation into the speleothem record at carefully selected cave sites where drip water flowpaths into the cave remain oxic speleothems hold the potential to retain records of atmospheric sulphur loading at the local and regional scale

oscillating quaternary water levels of the marmara sea and vigorous outflow into the aegean sea from the marmara sea black sea drainage corridor abstract detailed interpretation of single channel air gun and deep tow boomer profiles demonstrates that the marmara sea turkey experienced small amplitude 70 m fluctuations in sea level during the later quaternary limited in magnitude by the sill depth of the strait of dardanelles moderate subsidence along the southern shelf and quaternary glacio eustatic sea level variations created several stacked deltaic successions separated by major shelf crossing unconformities which developed during the transitions from global glacial to interglacial periods near the strait of dardanelles a series of sand prone deposits are identified beneath an uppermost holocene transparent mud drape the sandy deposits thicken into mounds with the morphology and cross sectional geometries of barrier islands sand waves and current generated marine bars all cross stratification indicates unidirectional flow towards the dardanelles prior to the deposition of the transparent drape which began 7000 years bp in strong support of the notion that the marmara sea flowed westwards into the aegean sea through the dardanelles at times of deglaciation in northern europe the global sea level curve shows that at 11 000 and 9500 years bp sea level rose to the sill depths of the straits of dardanelles and bosphorus respectively the effect from 11 000 to 9500 years bp was seawater incursion into the marmara sea drowning and formation of algal serpulid bioherms atop lowstand barrier islands and transgression of shelves and lowstand deltas at 9500 years bp glacial meltwater temporarily stored in the black sea lake developed into a vigorous southward flow toward the aegean sea forming west directed sandy bedforms in the western marmara sea and initiating deposition of sapropel s1 in the aegean sea this strong outflow persisted until 7000 years bp after which a mud drape began to accumulate in the marmara sea and euryhaline mediterranean mollusks successfully migrated into a progressively more saline black sea where sapropel deposition began most eastern mediterranean sapropels from s1 to s11 appear to correlate with periods of rising sea level and breaching or near breaching of the bosphorus sill these events are believed to coincide with times of vigorous outflow of low salinity fresh surface waters transiting the black sea marmara sea corridor and ultimately derived from melting of northern european ice sheets

paleoclimatic and paleoceanographic conditions leading to development of sapropel layer s1 in the aegean sea abstract sapropel s1 occurs as 25 35 cm thick black weakly laminated muds in aegean sea cores s1 was deposited between 9600 and 6400 yr b p during a period of isotopically depleted and relatively cool surface waters micro faunal and floral data indicate a major reduction in surface waters salinity during the deposition of s1 and oxygen isotopic data show a northerly fresh water source relatively light 13 c org and high pollen spore concentrations in s1 suggest increased influx of terrestrial organic carbon probably supplied by major rivers draining into the northern aegean sea benthic foraminifera indicate high nutrient low oxygen bottom waters for s1 and together with silt sized hematite and manganese coatings suggest that during the deposition of s1 surface sediments were oxic visual and xrd evidence of pyrite in s1 together with enrichments in s cu zn as ni cr and fe suggest that subsurface conditions were sufficiently reducing for so 4 2 reduction to occur probably by diffusion from surface oxic into subsurface anoxic sediments palynomorphs in s1 show large increases in terrestrial pollen and spores with the floral assemblage indicating significant influx from northern european rivers and minor african components associated with increased summer monsoonal rain abundance of dinoflagellates and amorphogen suggests some increase in primary productivity in response to increased influx of humic compounds however there is no evidence of upwelling the clay fraction in s1 shows notable decreases in smectite and kaolinite and reciprocal increases in illite and chlorite the combined data suggested that the evolution of s1 in the aegean sea largely resulted from stagnation of the surface waters during the final disintegration of the continental ice sheets rather than an increase in primary productivity and higher preservation of organic carbon on the sea floor

climate and cave control on pleistocene holocene calcite to aragonite transitions in speleothems from morocco elemental and isotopic evidence the occurrence of aragonite in speleothems has commonly been related to high dripwater mg ca ratios because mg is known to be a growth inhibitor for calcite laboratory aragonite precipitation experiments however suggested a more complex array of controlling factors here we present data from pleistocene to holocene speleothems collected from both a dolostone and a limestone cave in northern morocco these stalagmites exhibit both lateral and stratigraphic calcite to aragonite transitions aragonite fabrics are well preserved and represent primary features in order to shed light on the factors that control alternating calcite and aragonite precipitation elemental mg sr ba u p y pb al ti and th abundances were measured using la icp ms and analysed with principal component analysis samples were analyzed at 100 200 m resolution across stratigraphic and lateral transitions carbon and oxygen isotope ratios were analysed at 100 m resolution covering stratigraphic calcite to aragonite transitions results show that the precipitation of aragonite was driven by a decrease in effective rainfall which enhanced prior calcite precipitation different geochemical patterns are observed between calcite and aragonite when comparing data from the grotte de piste and grotte prison de chien this may be explained by the increased dripwater mg ca ratio and enhanced prior aragonite precipitation in the dolostone cave versus lower dripwater mg ca ratio and prior calcite precipitation in the limestone cave a full understanding for the presence of lateral calcite to aragonite transitions is not reached trace elemental analysis however does suggest that different crystallographic parameters ionic radius amount of crystal defect sites adsorption potential may have a direct effect on the incorporation of sr mg ba al ti th and possibly y and p

moroccan speleothem and tree ring records suggest a variable positive state of the north atlantic oscillation during the medieval warm period we present a magnesium mg and strontium sr record from an aragonitic speleothem grotte de piste morocco 34 n 04 w providing a reconstruction of effective rainfall from 619 to 1962 ad the corresponding drip site was monitored over 2 yr for drip water mg ca and sr ca ratios results show evidence for prior aragonite precipitation which can explain negative correlations between speleothem mg and sr concentrations the data shown here have important climate implications concerning the evolution of the north atlantic oscillation nao a comparison of the stalagmite data from grotte de piste with an updated tree ring based drought reconstruction from morocco and other nao related proxy records confirms that the medieval warm period mwp was dominated by nao conditions the stalagmite record and multiple proxy records from the iberian peninsula however suggest that considerable rainfall variability occurred during the mwp this implies that the nao has been more variable during the mwp than formerly suggested

last glacial holocene paleoceanography of the black sea and marmara sea stable isotopic foraminiferal and coccolith evidence multi proxy data and radiocarbon dates from several key cores from the black sea and marmara sea document a complex paleoceanographic history for the last v30 000 yr the marmara sea was isolated from both the black sea and the aegean sea during glacial periods when global sea level lowering subaerially exposed the shallow sills at the straits of bosphorus and dardanelles i e lake stage and reconnected through both straits during interglacial periods when rise of global sea level breached the shallow sills i e gateway stage micropaleontological data show that during the lake stage the surface water masses in both the marmara sea and black sea became notably brackish however during the gateway stages there was a low salinity surface layer and normal marine water mass beneath two sapropel layers are identified in the marmara sea cores sapropels m2 and m1 were deposited between v29 5 and 23 5 ka and v10 5 and 6 0 ka respectively micropaleontological and stable isotopic data show that the surface water salinities were reduced considerably during the deposition of both sapropel layers m2 and m1 and calculation using planktonic foraminiferal transfer functions shows that sea surface temperatures were notably lower during these intervals the presence of fauna and flora with black sea affinities and the absence of mediterranean fauna and flora in sapropels m1 and m2 strongly suggest that communication existed with the black sea during these times a benthic foraminiferal oxygen index shows that the onset of suboxic conditions in the marmara sea rapidly followed the establishment of fully marine conditions at v11 10 5 ka and are attributed to black sea outflow into the marmara sea since 10 5 ka these suboxic conditions have persisted to the present the data discussed in this paper are completely at odds with the flood hypothesis of ryan et al 1997 and ryan and pitman 1999 crown copyright 2002 elsevier science b v all rights reserved

palaeo climate reconstruction from stable isotope variations in speleothems a review abstract speleothems are now regarded as valuable archives of climatic conditions on the continents offering a number of advantages relative to other continental climate proxy recorders such as lake sediments and peat cores they are ideal materials for precise u series dating yielding ages in calendar years thereby circumventing the radiocarbon calibration problems associated with most other continental records stable isotope studies in speleothems have shifted away from attempting to provide palaeo temperature reconstructions to the attainable goal of providing precise estimates for the timing and duration of major o isotope defined climatic events characterised by high signal to noise ratios e g glacial interglacial transitions dansgaard oeschger oscillations the 8200 year event unlike the marine records speleothem data sets are not tuned and their independent chronology offers opportunities to critically assess leads and lags in the climate system that in turn can provide important insights into forcing and feedback mechanisms improved procedures for the extraction and measurement of stable isotope ratios in fluid inclusions trapped in speleothems are likely to provide in the near future a much enhanced basis for the quantitative interpretation of o isotope ratios in speleothem calcite the latter developments open up once again the tantalising prospect of palaeo temperature estimates but more importantly perhaps provide a direct test for a new generation of general circulation models whose hydrological cycles will incorporate the water isotopes the literature is reviewed briefly to provide for the reader a sense of the current state of the art and to provide some pointers for future research directions

pb concentrations and isotope ratios of soil o and c horizons in nord trondelag central norway anthropogenic or natural sources abstract soil o and c horizon samples n 752 were collected at a sample density of 1 site 36 km 2 in nord trondelag and parts of sor trondelag c 25 000 km 2 and analysed for pb and three of the four naturally occurring pb isotopes 206 pb 207 pb and 208 pb in a hno 3 hcl extraction soil o and c horizons are decoupled in terms of both pb concentrations and pb isotope ratios in the soil c horizon the grong olden culmination a continuous exposure of the precambrian crystalline basement across the general grain of the caledonian orogen is marked by a distinct 206 pb 207 pb isotope ratio anomaly no clear regional or even local patterns are detected when mapping the pb isotope ratios in the soil o horizon samples variation in the isotope ratios declines significantly from the soil c to the o horizon on average pb concentrations in the o horizon are four times higher and the 206 pb 207 pb isotope ratio is shifted towards a median of 1 15 in comparison to 1 27 in the c horizon it is demonstrated that natural processes like weathering in combination with plant uptake need to be taken into account in order to distinguish anthropogenic input from natural influences on pb concentration and the 206 pb 207 pb isotope ratio in the soil o horizon

hydrology in the sea of marmara during the last 23 ka implications for timing of black sea connections and sapropel deposition 1 sediments deposited under lacustrine and marine conditions in the sea of marmara hold a late quaternary record for water exchange between the black sea and the mediterranean sea here we report a multiproxy data set based on oxygen and strontium isotope results obtained from carbonate shells major and trace elements and specific organic biomarker measurements as well as a micropaleontological study from a 14c dated sediment core retrieved from the sea of marmara pronounced changes occurred in 18o and 87sr 86sr values at the fresh and marine water transition providing additional information in relation to micropaleontological data organic biomarker concentrations documented the marine origin of the sapropelic layer while changes in n alkane concentrations clearly indicated an enhanced contribution for organic matter of terrestrial origin before and after the event when compared with the black sea record the results suggest that the black sea was outflowing to the sea of marmara from the last glacial maximum until the warmer bolling allerod the first marine incursion in the sea of marmara occurred at 14 7 cal ka b p however salinification of the basin was gradual indicating that black sea freshwaters were still contributing to the marmara seawater budget after the younger dryas which is associated with a high input of organic matter of terrestrial origin both basins were disconnected resulting in a salinity increase in the sea of marmara the deposition of organic rich sapropel that followed was mainly related to enhanced primary productivity characterized by a reorganization of the phytoplankton population

black sea marmara sea quaternary connections new data from the bosphorus istanbul turkey abstract previous studies concluded that the bosphorus strait was formed during the quaternary by fluvial incision of a valley between the black sea to the north and the marmara sea in the south hitherto however few details of the evolution of this connection have been elucidated from the sediments deposited within the bosphorus itself we report here details of sedimentological and palaeontological evidence relating to this history obtained from five boreholes drilled into the unconsolidated sediment fill in the north central sector of the bosphorus together with nearby geophysical profiles the quaternary fill of this part of the bosphorus comprises two major facies associations yellow arkosic sands dominate the lower facies association a these are assigned a middle to late pleistocene age and the contained faunas have a lagoonal to lacustrine character and a black sea provenance paratethyan affinities the abruptly succeeding units of facies association b comprise fining and coarsening upwards units of coarse to fine shelly and clayey sands that alternate with shell bearing green clays these sediments were formed in a range of marine and coastal settings and biostratigraphic evidence and absolute dating demonstrate the mid late holocene age of this upper unit initially brackish faunal assemblages in this upper unit show an upward increase in marine and mediterranean affinities integrating these new data with previously published observations from coeval deposits in the southern bosphorus and izmit bay ne marmara sea we conclude that during the late pleistocene and early holocene a topographic barrier existed in the south central sector of the bosphorus on both sides of which estuarine and lagoonal sediments accumulated with distinctive black sea and mediterranean faunas during a significant rise in sea level between 7000 and 5300 years ago this barrier was finally submerged permitting interchange of marine waters between the mediterranean and the black sea and creating the present oceanographic situation this evolution conflicts with the cataclysmic role of the bosphorus in the early holocene as postulated in the catastrophic flood hypothesis of ryan et al mar geol 138 1997 119 126 annu rev earth planet sci 31 2003 525 554 it also contrasts with the history recorded from the gulf of izmit where intermittent connection between these two bodies of water throughout much of the quaternary is evident

on the origin of the bosphorus abstract the palaeozoic upper cretaceous basement palaeomorphology of the bosphorus the strait of istanbul bears the evidence of a valley of a palaeostream running to the black sea in the north a palaeobasin deeper than 160 m opening to the sea of marmara in the south and a barrier between these two features this suggest that the northern part of the bosphorus was formed mainly by fluvial activity whereas the southern part developed as a basin by faulting the recent sediment thickness exceeds 130 m in the basin indicating that the southern part of the bosphorus was once essentially depositional rather than an erosional the present form of the bosphorus was established in holocene time by the connection of the basin in the south with the stream in the north the barrier and the stream valley in the north have been deepened by erosion and faulting to form a strait connecting the black sea and the mediterranean

catastrophic flooding of the black sea abstract decades of seabed mapping reflection profiling and seabed sampling reveal that throughout the past two million years the black sea was predominantly a freshwater lake interrupted only briefly by saltwater invasions coincident with global sea level highstand when the exterior ocean lay below the relatively shallow sill of the bosporus outlet the black sea operated in two modes as in the neighboring caspian sea a cold climate mode corresponded with an expanded lake and a warm climate mode with a shrunken lake thus during much of the cold glacial quaternary the expanded black sea s lake spilled into to the marmara sea and from there to the mediterranean however in the warm climate mode after receiving a vast volume of ice sheet meltwater the shoreline of the shrinking lake contracted to the outer shelf and on a few occasions even beyond the shelf edge if the confluence of a falling interior lake and a rising global ocean persisted to the moment when the rising ocean penetrated across

lead isotope variability in speleothems a promising new proxy for hydrological change first results from a stalagmite from western germany abstract we studied an aragonitic section of ca 6 cm length of stalagmite hbsh 1 from the huttenblaserschachthohle western germany 230 th u dating revealed that this section grew between 210 and 190 ka with a relatively uniform growth rate of 3 1 m a 1 for the first time we determined pb isotope ratios 207 pb 206 pb and 208 pb 206 pb in a stalagmite by laser ablation la icp ms in addition we analyzed various trace element mg al si p mn sr pb and th concentrations the results indicate that pb in hbsh 1 originated from two external sources i the regional galena pbs mineralization with high pb content as well as isotope ratios and ii the carbonate fraction in the host rock with low pb content as well as isotope ratios except for sr all trace elements show similar variations probably driven by the amount of infiltration into the cave system this is probably the result of the similar transport and incorporation mechanisms of these elements as colloids and or particles the pb isotope ratios also show a strong correlation with trace element variability strongly suggesting that the pb isotope variability in hbsh 1 has the potential to be used as a promising new proxy for hydrological change based on the observed variability we identify two phases from 204 9 to 201 5 and from 198 4 to 195 9 ka with enhanced water infiltration in the cave region between 210 0 and 204 9 201 5 and 198 4 as well as 195 9 and 190 0 ka less infiltration occurred

annual trace element cycles in calcite aragonite speleothems evidence of drought in the western mediterranean 1200 1100 yr bp each of two calcitic stalagmites from grotte de clamouse herault southern france displays a discrete aragonite layer dated at around 1100 yr bp the layer of fanning aragonite ray crystals is immediately preceded by calcite with mg and sr compositions that are uniquely high for the past 3 kyr trace element compositions close to the boundary between original aragonite and calcite are consistent with quasi equilibrium partitioning of trace elements between the phases study of modern dripwaters demonstrates that pronounced covariation of mg ca and sr ca ratios in dripwater occurs owing to large amounts of calcite precipitation upflow of the drips that fed the stalagmites trace element to ca ratios are enhanced during seasonally dry periods ion microprobe data demonstrate a pronounced covariation of trace elements including mg and sr in calcite and sr u and ba in aragonite the mean peak spacing is close to the long term mean of annual growth rates determined by differences in u series ages and so the trace element peaks are interpreted as annual the trace element chemistry of the stalagmites on annual to inter annual scales thus directly reflects the amounts of prior calcite precipitation interpreted as an index of aridity the longer term context is a multi decadal period of aridity 1200 1100 yr bp possibly correlated with an analogous episode in central america the arid period culminated in the nucleation of aragonite but within a decade was followed by a return to precursor conditions copyright 2005 john wiley sons ltd

sea level changes and related depositional environments on the southern marmara shelf abstract petrographic data obtained from 182 surface sediment samples together with the available bathymetric data are used to investigate the effects of the last major sea level changes on shelf evolution in the southern sea of marmara grain size analysis reveals the presence of at least three belts or zones which are rich in coarse grained sand and gravel sediments these coarse grained belts which are up to 45 km long 15 km wide show up to 20 m of relief and are presently found at 40 80 m average 60 m water depths based on microscopic examination and residual analysis the sediments from these belts are interpreted as indicators of high energy shallow waters where detrital siliciclastics with some benthic contribution accumulated the presence of a 62 65 m deep sill in the canakkale strait and the consideration of sea level curves would suggest that the marmara shelves must have been subaerially exposed down to 65 m water depths for about 10 000 yrs 22 000 12 000 yrs b p sufficient time to modify former shelf topographies and form such bottom relief while difficult to date we believe that coarse grained belts found on the southern marmara shelf must be relict i e former shorelines beaches and their formation is largely related to low stands of sea level during the late pleistocene regression and early holocene transgression however the available high resolution seismic profiling data suggest that the neotectonism in this seismically active sea of marmara plays an important role to explain the raise of these older shorelines to their present levels on the sea floor

late quaternary sedimentation in the strait of bosporus high resolution seismic profiling abstract uniboom profiling supported by borehole data in the southern part of the bosporus revealed that close to its banks holocene sediments are underlain by the faulted slopes of a valley cut in many places into the palaeozoic bedrock away from the banks the sediments thicken and their boundary with the underlying pleistocene deposits is defined by an erosional surface at about the 80 ms twt this surface marks the initiation of marine currents in the valley as its deeper parts began to be submerged in the late pleistocene to early holocene marine spillway phase the upward coarsening holocene sequence records the subsequent evolution of the present two way marine strait the sequence is divided into three seismostratigraphic units the lowest one constitutes an onlapping fill deposited under salt wedge estuarine conditions when sediment input and runoff discharge were high and sealevel was still rising but the flow of mediterranean waters into the black sea was not continuous it fills low areas and is well developed under a sill close to the southern entrance of the strait as sealevel rose closer to its present level and the rate of terrigenous input decreased in the middle holocene this unit began to be eroded and reworked by strong bottom currents the second unit records the transitional stage between the estuarine phase and the present two layered current system its seismic facies and sedimentary features indicate deposition under high energy conditions and shifting loci of accumulation the third surficial unit is a thin depositional lag rich in shell fragments blanketing the other two units it records deposition under fully marine conditions and flow of powerful bottom currents during the last few millenia

holocene climate variability in central germany and a potential link to the polar north atlantic a replicated record from three coeval speleothems here we present high resolution trace element and stable isotope records from three coeval holocene stalagmites from the herbstlabyrinth cave system central germany all stalagmites were precisel