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

bomb 14c time history recorded in two modern stalagmites importance for soil organic matter dynamics and bomb 14c distribution over continents carbon 14 activity measurements made by accelerator mass spectrometry on two modern stalagmites from the han sur lesse cave belgium and from the postojna cave slovenia permit the construction of 14c activity a14c time series over the last 50 years a high precision chronology is given by annual laminae in the first stalagmite and by a specific mark explosion in the postojna cave in 1944 in the second one in both stalagmites 14c activity increase due to nuclear tests in the atmosphere is remarkable however instead of a sharp peak like the one observed in the atmosphere around 1963 1964 the 14c activities of the stalagmite caco3 show an abrupt increase with an offset of 1 10 years followed by a high activity plateau for the han sur lesse sample and a slight decrease for the postojna sample for both stalagmites the variation of the a14c amplitude between pre and post bomb period is much lower than the atmospheric record which demonstrates the damping effect of the soil carbon reservoir we have modeled the caco3 activities using fractionation processes between atmosphere co2 soil co2 and organic matter om dissolved inorganic carbon and stalagmite caco3 in both cases studied the model and former soil studies suggest that co2 from soil organic matter som decomposition which has a slow turnover i e 1 y is of major importance in winter when the development of speleothem is the most important combined with the fact that 80 90 of the stalagmite carbon comes from soil co2 this produces a damping effect on the speleothem a14c consequently the geochemical time resolution at least for speleothem carbon is much lower than the structural resolution given by annual laminae alternations and is mainly controlled by soil carbon dynamics a14c and 13c are smoothed over several years differences between the 14c time series of the han sur lesse and postojna stalagmites are likely to be due to the double amount of precipitation in postojna which produces a faster soil om turnover and thus a system which is more sensitive to atmospheric changes

elevated and variable values of 13c in speleothems in a british cave system 13c isotope variations in speleothems have been investigated for samples from the british isles where plants which use the hatch slack or c4 photosynthetic pathway are not present the range of 13c expected in speleothem carbonate formed in isotopic equilibrium with soil co2 derived from the overlying c3 vegetation should thus fall in the range 12 to 6 forty one actively growing speleothem samples from low discharge sites were analysed from stump cross caverns yorkshire england ten percent have 13c greater than 6 in addition a large range of 13c was observed 8 06 1 38 a 1 variability of 17 with adjacent samples having 13c differing by a maximum of 4 74 similar findings were obtained from a review of analyses of late quaternary speleothem samples from the british isles with 75 of flowstone samples and 57 of high flow stalagmite samples exhibiting elevated 13c three possible processes are proposed as possible causes of elevated 13c in speleothems firstly fractionation may occur between the stalactite and stalagmite due to evaporation or degassing secondly degassing of the groundwaters may have occurred within the aquifer before reaching the cave void allowing release of some co2 from the water whilst remaining saturated in calcium finally the elevated 13c may be due to short water residence times in the soil such that equilibrium between soil water and soil co2 is not reached evidence presented here demonstrates that any one of these mechanisms may be important in the karst areas of the british isles caution is needed before interpreting the 13c signal within speleothems in terms of palaeovegetation

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

start of the last interglacial period at 135 ka evidence from a high alpine speleothem a detailed study of growth periods of a flowstone from spannagel cave in the zillertal alps austria at 2500 m above sea level a site highly sensitive to climate changes offers unprecedented new insights into pleistocene climate change in central europe flowstone sample spa 52 has a high u content to 116 ppm analyses of this sample reveal that episodes of calcite deposition started at 204 3 ka 135 1 2 ka and 122 ka suggesting that at these times the mean air temperature at this high alpine site was within 1 5 c of the present day condition the beginning of growth at 135 ka corresponds to the ending of the last glaciation and is concordant with a midpoint age for the penultimate deglaciation at 135 2 5 ka as deduced from the absolutely dated oxygen isotope curve in sediments from the bahamas as well as with recent coral evidence from barbados indicating a high sea level already by 135 8 0 8 ka this set of data supports evidence against northern hemisphere forcing of termination ii because the insolation maximum is at 127 ka

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

a high resolution record of holocene climate change in speleothem calcite from cold water cave northeast iowa high precision uranium thorium mass spectrometric chronology and 18o 13c isotopic analysis of speleothem calcite from cold water cave in northeast iowa have been used to chart mid holocene climate change significant shifts in 18o and 13c isotopic values coincide with well documented holocene vegetation changes temperature estimates based on 18o 16o ratios suggest that the climate warmed rapidly by about 3 c at 5900 years before present and then cooled by 4 c at 3600 years before present initiation of a gradual increase in 13c at 5900 years before present suggests that turnover of the forest soil biomass was slow and that equilibrium with prairie vegetation was not attained by 3600 years before present

high resolution mapping of uranium and other trace elements in recrystallized aragonite calcite speleothems from caves in the pyrenees france implication for u series dating abstract aragonite and calcite speleothems were sampled in the cave of pierre saint martin pyrenees atlantiques france these speleothems contain significant amounts of uranium and strontium which were measured spatially and chemically by nuclear microprobe analysis sr and u distributions are highly varied with a marked contrast between aragonite and calcite because the aragonite concentrates sr and u on the other hand zn is preferentially located in calcite and in layers of organic matter trapped in caco 3 sr contents ranged from 440 to 1100 g g in the calcite and 4900 to 18 500 g g in the aragonite u concentrations show remarkably high values from 11 to 19 g g in the calcite and 89 to 350 g g in the aragonite these u and sr concentrations are amongst the highest measured in supergene speleothems deposited by infiltrating meteoric waters x ray absorption experiments with synchrotron radiation suggested that uranium was incorporated in its hexavalent oxidation state in both aragonite and calcite recrystallization from aragonite into calcite was indicated by micromorphological observations for some of the samples this recrystallization process may explain the uranium loss in neogenic calcite deposits and consequently the opening of the geochemical system which can lead to errors in age dating with the u series dating method uranium loss in recrystallized calcite is one of the important aspects to be considered in u series dating and more generally for u geochemical stability in caco 3

polycyclic aromatic hydrocarbons in stalagmites occurrence and use for analyzing past environments this article presents a preliminary investigation into the value of polycyclic aromatic hydrocarbons pahs as markers for interpreting past environments in karst areas we analyzed a core sample representing the last 400 years growth from a massive stalagmite in the chevaline cave vercors france together with the soil overlying the karst directly above the stalagmite during the last millennium this area has been profoundly affected by human activities such as slash and burn agriculture charcoal burning and forestry these activities may have induced changes in pah production in the soil and thus in the pah record in the stalagmite pahs were extracted using both the soxhlet method and the ultrasonic method in order to compare extraction yields the ultrasonic method in conjunction with classic hplc fluo analysis was adopted for the analyses as it gave the greater yields pah distributions were obtained for the stalagmite and for the overlying soils the sum of the pah measured in the stalagmite ranges from 18 to 30 ng g furthermore the more soluble and labile pahs lighter than anthracene dominated the pah distribution in the stalagmite about 90 of low molecular weight pah however we did not find any obvious source fingerprints in the soil or the stalagmite and we observed an unexpected discrepancy between the pah distributions in the stalagmite and its stratigraphy which is controlled by mineral and organic inclusions although pah analyses can provide valuable data about the transfer of organic compounds in the karst it is difficult to extract meaningful paleoenvironmental information from pahs in stalagmites over the time scale of this study

trace element variations in an annually layered stalagmite as recorders of climatic changes and anthropogenic pollution in central china abstract we analyzed variations in the sr ca ba ca ree ca ree rare earth element zn ca and pb ca ratios preserved in an annually layered stalagmite xl21 from central china the stalagmite record spans the 95 year period ad 1914 2008 the sr ca and ba ca ratios have a significant positive correlation with the stalagmite s growth rate suggesting that they were primarily controlled by growth rate variations variations in ree ca ratios are consistent with local temperature changes suggesting temperature influenced ree concentrations in the stalagmite over decadal to annual timescales higher temperature in this humid area can increase vegetation cover microbial activity and organic decomposition in the soil resulting in enhanced pco2 organic matter concentration and reduced ph and consequently increased ree mobilization from the overlying soil layer and host rock higher temperatures may also increase the natural zn mobilization from the overlying soil mediated by organic matter and consequently may have led to increased zn retention in xl21 an increasing trend is seen in the pb ca ratios from xl21 since 1985 which is consistent with increased lead production in this area and indicates an increase in mine derived lead pollution in the local environment over the past 30 years

interhemispheric anti phasing of rainfall during the last glacial period abstract we have obtained a high resolution oxygen isotopic record of cave calcite from caverna botuvera 27 13 s 49 09 w southern brazil which covers most of the last 36 thousand years ka with an average resolution of a few to several decades the chronology was determined with 46 u th ages from two stalagmites tests for equilibrium conditions show that oxygen isotopic variations are primarily caused by climate change we interpret our record in terms of meteoric precipitation changes hence the variability of south american monsoon sam intensity the oxygen isotopic profile broadly follows local insolation changes and shows clear millennial scale variations during the last glacial period with amplitudes as large as 3 but with smaller centennial scale shifts 1 during the holocene the overall record is strikingly similar to but strongly anti correlated with a number of records from the northern hemisphere we compared our record to other precisely dated contemporaneous records from hulu cave eastern china minima in 18o wet periods intense sam at our site are synchronous with maxima in 18o dry periods weak east asian monsoon eam in eastern china within precise dating errors and vice versa this anti phased precipitation relationship between two low latitude locations may be interhemispheric in extent based on comparison with records from other sites precipitation anti phasing may be related to north south shifts in the mean position of the intertropical convergence zone itcz and asymmetry in hadley circulation in two hemispheres associated not with seasonal changes as observed today but with millennial scale climate shifts the millennial scale atmospheric see saw patterns that we observe could have important controls and feedbacks on climate within hemispheres because of water vapor s greenhouse properties

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

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

in situ observation of contour currents in the northern south china sea applications for deepwater sediment transport deepwater currents and related suspended sediment concentration were obtained by an acoustic doppler current profiler adcp mooring system in the northern south china sea from september 2011 to may 2013 to characterize the occurrence of contour currents and to evaluate their sediment transport capacity magnitude of the current velocity generally varied in the range of 0 2 cm s with a dominant flow direction of 250 southwestward the observed contour current defined as the along slope component of the deepwater currents has a tunnel like vertical structure with the largest velocity occurring in the middle of the tunnel and decreasing outwards both the magnitude and the depth range of the maximum velocity display evident inter seasonal variations with the strongest velocity in summer and the weakest in spring while the thickness of the contour currents was the highest in winter and the lowest in spring we also found that passing through of the deep reaching mesoscale eddies significantly affected the magnitude and direction of the contour currents the suspended sediment concentration ssc estimated from echo intensities of the adcp is the highest at the near bottom 400 g l and decreases upwards to 10 g l at water depth shallower than 1750 m high ssc is mostly observed during periods of low magnitude of the contour currents suggesting resuspension of sediment from the seafloor is not the major controlling factor of these high ssc events our observation also suggests that the major role that contour currents play is to transport sediment from the sources through keeping sediment suspended above the lower continental slope of the south china sea

the hekla 3 volcanic eruption recorded in a scottish speleothem recent research has demonstrated the presence of annual luminescent growth banding in a stalagmite from sutherland n w scotland baker smart edwards and richards 1993 the banding record of this sample contains a short duration increase in annual band width indicating a doubling of growth rate for a period of four years predicted growth rates derived from calcite precipitation kinetics are compared with observed growth rate variability to demonstrate that such a doubling of growth rate would not be expected within the probable range of normal climate variation the growth rate peak is dated to 1135 130 bc by thermal ionization mass spectrometric 238u 234 u 230th dating not inconsistent with the timing of the hekla 3 volcanic eruption this event may explain the observed variation in growth rate and provide a new source of evidence for interpretation of the effects of large explosive eruptions

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

impact of ancient metal smelting on arsenic pollution in the pecora river valley southern tuscany italy abstract a significant as anomaly has been reported in the literature for stream sediments and unlithified quaternary deposits of the pecora river valley in southern tuscany extending from the colline metallifere pyrite base metals district to the tyrrhenian sea the as anomaly spreads over several square kilometers around a core that exceeds 500 ppm several source contributions from natural to anthropogenic have been invoked to explain the observed as distribution in the pecora valley including the metal working industry which was active in this area particularly in etrusco roman times and in the middle ages in order to evaluate the contribution of ancient mining and metallurgical activities in the pecora valley to elevated as concentrations in the environment a detailed mineralogical and geochemical survey of metallurgical slags and smelted ore minerals was undertaken from six different sites through the pecora valley poggio butelli etrusco roman iron slags sata creek arialla marsiliana forra and cascata sites all medieval base metals slags the as content of etrusco roman slags is relatively low few tens of ppm whereas medieval slags show variable but higher amounts of base metals ag ranging from tens to tens of thousands ppm and as up to 267 ppm with average contents of about 40 ppm arsenic is mostly partitioned in sulfides disseminated through the glassy groundmass rather than in solid solution with the glassy matrix remnants of the ore used for base metal and ag smelting during the middle ages had the highest as contents up to about 1000 ppm the overall as concentration in the slags independent of age and type is generally lower than that found in stream sediments and quaternary alluvial deposit outcrops of the upper pecora valley textural observations indicate that exogenous alteration of slags is minor and mostly confined to superficial exposures of matte droplets or along fractures metal particles embedded within the glassy groundmass even those located a few micrometres from the surface appear to be unaltered it is suggested therefore that as and contaminant metal contributions to the pecora valley by archaeometallurgical slags was minor at least for slags from the last 2500 to 700 a bp similarly based on gross mass balance calculations airborne release of as due to smelting roasting operations in the past cannot account for the observed extent of the as anomaly in stream sediments and quaternary deposits although residues of unsmelted or partially smelted fe cu pb zn charges or fluxes for base metal metallurgy contain much greater amounts of as than smelting slags their relatively low abundance would limit the overall input of as into the pecora river valley on the other hand concurrent research seems to indicate a major geogenic contribution to the as anomaly in the pecora valley

freshwater bivalves tell of past climates but how clearly do shells from polluted rivers speak abstract freshwater bivalves margaritifera margaritifera linnaeus and unio crassus philipsson from rivers in sweden 79 specimens and england one specimen were used to study the effects of human induced pollution on shell growth table 1 we analyzed variations in annual and daily shell growth rates of 80 specimens from unpolluted and polluted ph

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

seasonal trace element and stable isotope variations in a chinese speleothem the potential for high resolution paleomonsoon reconstruction abstract we report the presence of clear annual cycles in trace element mg ca sr ca ba ca and u ca and stable isotope 18o and 13c composition in an annually banded stalagmite from heshang cave hubei province china 30 44 n 110 42 e through a combination of micromilling and in situ analysis la mc icpms we measured geochemical variations across 16 annual growth bands to assess their potential as seasonal resolution paleomonsoon proxies to facilitate comparison with modern climatic and environmental data we created composite annual cycles for each proxy by stacking 6 well defined years speleothem 18o variations 10 8 to 8 5 are controlled by seasonal variations in temperature and drip water 18o which lead to maximum values during may around the time of summer monsoon onset this provides a chronological marker which can be used to constrain the timing of the other geochemical cycles the composite cycles reveal a strong positive correlation between mg ca sr ca ba ca and 13c values in the micromilled section r2 0 65 0 98 with minimum values occurring around may maximum u ca values occur at the same time we present simple models which show that these correlations as well as the observed ranges of mg ca 14 1 to 22 4 mmol mol sr ca 0 2 to 0 4 mmol mol and 13c 12 5 to 10 7 may be fully explained by progressive co2 degassing and calcite precipitation from an initially saturated solution using realistic initial conditions for heshang cave t 18 c mg casolution 0 84 mol mol sr casolution 0 69 mmol mol 13ctdic 16 75 we find that the observed relationships can be produced by using dmg 0 016 and dsr 0 30 within the range of expected values the model suggests that the fraction of ca removed from the solution ranges from 0 to 30 to produce the observed seasonal cycles this variation may be due to two related processes which occur during drier periods 1 increased prior precipitation of calcite in the epikarst or on the cave ceiling and or 2 a greater degree of co2 degassing and calcite precipitation on stalagmite surfaces when drip rates are lower both mechanisms would have the effect of enriching speleothem mg ca sr ca ba ca and 13c values during drier periods past variations in heshang carbonate chemistry may therefore be useful as seasonal resolution proxies for past rainfall

east asian monsoon evolution and reconciliation of climate records from japan and greenland during the last deglaciation abstract east asian monsoon eam evolution during the last deglaciation has been shown repeatedly to be aligned with paleoclimatic changes in the north atlantic based on climate reconstructions comparing asian speleothem records with greenland ice cores in contrast to this finding paleoclimatic reconstructions based on lake suigetsu sediment cores suggest that past eam variability in japan was not always coherent with climatic variability recorded in greenland ice cores we resolve this discrepancy using an absolute dated stalagmite 18 o record that covers the period between 15 5 and 10 7 thousand years before present ka before ad 1950 this stalagmite record is from nearby maboroshi cave japan and shows climate changes that are synchronous with those of chinese caves and greenland ice cores our results support an effective teleconnection between low and high latitudinal climate systems during the transitions into the bolling allerod ba warming at 14 6 ka and the younger dryas cooling at 12 8 ka in the north atlantic however our results also indicate monsoonal intensification during the ba coincident with decreasing temperatures in greenland from 14 6 to 12 8 ka we explain this decoupling as a result of the interhemispheric bipolar seesaw climate system discrepancies between lake suigetsu radiocarbon age data sets and other radiocarbon calibration archives can also be removed when our maboroshi record is used to adjust the lake suigetsu age model as well as resolving temporal ambiguities in the lake suigetsu paleoclimate record

atmospheric pb pollution by pre medieval mining detected in the sediments of the brackish karst lake an loch mor western ireland abstract this paper presents results of geochemical investigations of lake sediments from the karst lake an loch mor aran islands including the first highly resolved record of atmospheric roman pb pollution for ireland the natural pb influx into the lake is largely contributed by 3 pb components which differ in their isotopic composition detrital influx of pb from the siliciclastic input dissolved influx of pb released by weathering of the local limestone and dissolved influx of seawater pb the balance between the 3 pb components varies in concert with the hydrological evolution of the lake the influx of pb in dissolved form is estimated by geochemical mass balance assuming that the siliciclastic influx is characterised by the pb al ratio of the late glacial clastic sediments it typically accounts for 50 80 of total pb input in the holocene sediments of an loch mor the natural dissolved influxes of pb sc and y reach a similar order of magnitude normalisation with sc and y is applied to quantify contributions from anthropogenic pb based on continuous sampling of 1 cm sample slices variations in the influx of roman pb could be reconstructed at a time resolution of c 5 a combined geochemical and pb isotope mass balance is used to characterise the isotopic composition of anthropogenic pb distinctly enhanced influx of anthropogenic pb occurs in the 1st and 2nd century ad and shows high variability on decadal scale this is in contrast to central european pb records which document a gradual increase and decrease in ancient atmospheric pollution by roman pb the reconstructed high variability in the influx of roman pb in an loch mor documents variations in the wind regime of western europe temporarily favouring the transport of atmospheric pb to western ireland

black carbon pollution of speleothems by fine urban aerosols in tourist caves speleothems in the karst caves of south korea which receive many visitors are losing their aesthetic appeal due to black coloring mineralogical textural and chemical analyses were conducted on the speleothems to discover the cause of the discoloration an abrupt color change from the natural color seen in the inner zones to the black color of the outer zones suggests that pollution commenced just after the opening of caves to visitors and has continued since then the main mineral compositions of both the outer black and the inner layers are the same but the concentration of non carbonate carbon is much higher in the black layers than in the inner layers electron microscopy showed that chain like agglomerates ca 0 2 1 1 m diameter of sub micrometer carbon spheres ca 0 02 0 05 m diameter are absent from the inner layer but present in the black layer as well as in the cave aerosol on the basis of their sub micrometer size agglomeration pattern and composition the carbon spheres and their agglomerates are considered to originate mostly from automobile exhaust they are presumed to have been carried into the caves by visitors from urban environments and then deposited on the surface of growing speleothems protection of speleothems from discoloration requires control of these fine anthropogenic aerosols

cave minerals of the world 2nd edition by carol hill and paolo forti national speleological society huntsville al 463 p isbn number 1 879961 07 5 70 00 think about all of those spectacular displays of mineral crystals that grace the world s mineral museums a great many of the large faceted crystals grew in some sort of cavity over long periods of time such mineral crystals are discovered in vugs pockets and cavities exposed in mines and quarries the conditions under which they were found are very different from the conditions under which they grew the fluids from which they grew are long gone a challenge for mineralogists to deduce from the surviving clues of trace elements isotopes and fluid inclusions now consider a cave it also is a cavity maintaining conditions of constant temperature water vapor pressure and carbon dioxide pressure for long periods of time this is also an environment where minerals can grow but in the case of many caves human observers can watch the growth process in progress some cave minerals appear as large faceted crystals some are nondescript crusts of little beauty but fascinating mineralogy most have formed from flowing dripping and seeping water and thus take on shapes dictated by the idiosyncrasies of the moving water such mineral deposits are known as speleothems stalactites stalagmites flowstone and a host of more intricate shapes hill and forti illustrate speleothems with some spectacular color photographs the authors have solicited contributions from cave photographers all over the world and without exception the

on pollution of the biosphere in industrial areas the example of the donets coal basin abstract the distribution of heavy metals nitrates and other elements and compounds was studied in the donets basin biosphere the neomineralization processes in burning coal waste heaps were investigated more than 10 minerals were found for the first time in the donets basin the most frequently occurring are native sulphur and ammonium chloride in the process of geochemical mapping 30 000 soil samples were collected and analyzed the soil content of hg as pb zn cd and other elements was determined these concentrations often exceed the permissible level of concentration plc the soil mercury content is high in 90 of the donetsk city territory in some places it is 7 5 9 0 mg kg several times higher than the plc a high mercury concentration up to 19 mg kg was found in the soils of the central donbas area where the large coke chemical mercury and metallurgical plants are situated the air mercury content is about 25 30 pg l 1 pg 10 12 g in donetsk city and it is 300 1000 pg l or more near the nikitovsky mercury plant the background level is 1 6 1 8 pg l geochemical anomalies of arsenic mercury nitrates and other toxic elements and compounds were detected in 6000 donbas subsurface water samples near donetsk the arsenic content is up to 24 times and the mercury content is up to 3 10 times higher than the plc nitrate pollution of the donbas subsurface water covers 80 of the territory the nitrate content is as high as 500 1000 mg l and more plc is 45 mg l the sources of biosphere pollution by heavy metals and nitrates are coal waste heaps coal mines coke chemical plants metallurgical plants and other enterprises toxic pollution of the donbas biosphere negatively influences human health further systematic investigations of the donbas biosphere need to be conducted involving cooperation between scientists of different countries under joint programs

can tree ring chemistry reveal absolute dates for past volcanic eruptions discussion of the significance of volcanically induced impacts on human history the natural environment and climate through the holocene has frequently stalled because of controversy concerning certain key volcanic eruptions and their precise relationships with the archaeological environmental record a major stumbling block in such debates is a failure to obtain precise and accurate dates for many of these key volcanic events most existing dates currently float against archaeological historical environmental and climate data a potential means to resolution lies with tree rings these can be dated precisely by dendrochronology are available from a wide range of loci around the world and can record global climatic influences it has been suggested that certain growth anomalies in dendrochronological sequences could offer proxy absolutely dated records of major climatically effective volcanic eruptions however this assertion has been widely disputed given the lack of a direct positive causal connection the hypothesis that the required connection may be chemically encoded in individual annual growth rings from dated sequences is explored here both via review of existing literature on dendrochemical techniques and by la icp ms chemical analysis of two tree ring sequences it is concluded that dendrochemistry provides a promising means by which absolute dates may one day be attributed to key volcanic eruptions of pre modern times 2005 elsevier ltd all rights reserved

annually laminated lake sediments and the study of quaternary environmental changes a review abstract annually laminated lake sediments non glacial varves have in recent years been discovered in increasing abundance especially since the development of in situ freezer samplers so far the majority of examples have been found in three main areas eastern north america northern and central europe and east and central africa a much more widespread distribution seems highly probable however the formation of annual laminations in freshwater lakes is governed by a number of factors the most important of which appears to be morphometry seasonality of sediment supply which may be controlled by physical biological or even cultural processes in the lake or in its catchment is also clearly significant four main types of laminations here termed ferrogenic calcareous biogenic and clastic have so far been recorded although it is quite clear that others exist special field and laboratory techniques are needed in order that the particular properties of varved sediments may be fully exploited annually laminated sediments have so far been applied to the investigation of a number of aspects of the quaternary these include the study of a geochronology b climatic change c vegetation history especially the role of fire in forest ecosystems d the calculation of rates of sediment influx to lakes and of rates of erosion from their catchments and e the monitoring of processes in the modern environment such as heavy metal pollution eutrophication and acid rain annually laminated lake sediments combine an internal independent chronology with the preservation of discrete visible increments of seasonal and annual sedimentation given this unique property and the likelihood that many more examples will be discovered the prospects for further applications of studies of these sediments to the investigation of the quaternary seem very good indeed

speleothems and pine trees as sensitive indicators of environmental pollution a case study of the effect of uranium ore mining in hungary abstract four decades of u ore production in hungary provides an opportunity to study the possible environmental effects of mining the study reveals significant changes in chemical composition of a stalagmite cave deposit the good fit between u content changes in the studied deposit and the u ore production rate support the assumption of the relationship with mining activity an independent chemoenviromental archive living pine pinus sylvestis trees were also investigated data on pine tree cores collected from the same region show different levels of pollution cu zn mn u after the 1950s and 1960s linked to the opening of mines and subsequent dust fallout around the site elevated concentrations of detritally derived elements si al th coupled with a rise in u concentration and change in 234 u values of the stalagmite suggest increasing amounts of mine derived dust from 1 to 3 km distance that settled and washed into the karst system the combined usage of different proxies not only provides historic records for the anthropogenic impact in the environment but also allows the timing of u concentration increases within the stalagmite and the identification of elemental behavior from the pollution this study shows that complementary geochemical archives such as stalagmites and tree rings used together can enhance understanding of past environmental contamination

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

initial intensification of east asian winter monsoon at about 2 75 ma as seen in the chinese eolian loess red clay deposit 1 the loess paleosol red clay sequence in the chinese loess plateau provides a record of the evolution of atmospheric circulation and monsoon climate over east asia during the last 7 8 ma detailed analyses of the baishui and jingchuan sections show that the grain size of eolian loess increased abruptly at about 2 75 ma which is accompanied with a reversal of depositional pattern from the red clay to loess paleosol deposits suggesting that the dust transporting circulation was reorganized this is the earliest clear expression of the east asian winter monsoon intensification at the pliocene pleistocene climate transition coincident with the initiation of major northern hemisphere glaciation over the eurasian arctic and northeast asia implying that at the early stage of the pliocene pleistocene global cooling the east asian winter monsoon circulation had been closely linked with the build up of ice sheet and climate changes over the high latitudes of northern hemisphere the intensified winter monsoon winds would have in turn acted as an important positive feedback in strengthening global cooling by increasing albedo and dust loading

comment on linking the mesoproterozoic belt purcell and udzha basins across the west laurentia siberia connection abstract paleogeographic reconstruction of the northern siberian craton against southwestern laurentia in accordance with paleomagnetic data basement piercing points and the best fit of the rift margins aligns mesoproterozoic dike and sill swarms in northeast siberia with correlative ones in montana and wyoming it also juxtaposes the mesoproterozoic belt purcell basin of west laurentia against the mesoproterozoic udzha basin of the northern siberian craton we review the veracity of this hypothetical belt purcell udzha basin as a test of our siberia west laurentia reconstruction various elements of the structural framework of the basins are closely aligned in the reconstruction the udzha trough is aligned with the st mary moyie fault zone and vulcan basement structure of southwestern canada the khastakh trough is aligned with the helena embayment of central montana parts of the belt purcell supergroup appear to correlate with parts of the riphean section in northeastern siberia however the siberian section appears to be much thinner than the belt purcell section and precise correlation is not possible with present stratigraphic and geochronological data the reconstruction leads to the prediction that the udzha rift channeled sediment from a cratonic pediment into the delta and alluvial fan complex in the deep belt purcell rift basin distributary channels may have shifted within the udzha basin to feed shifting depocenters in the belt purcell basin details of age and tectonic evolution for the udzha basin are less clear than for the belt purcell basin but we outline specific geological relationships predicted by the reconstruction model and suggest tests for future research

paleoclimatic evolution of the sw and ne south china sea and its relationship with spectral reflectance data over various age scales abstract spectral analysis of sediment from international ocean discovery program iodp site u1433 in the south china sea can be used to constrain humidity and temperature through time by constructing hematite goethite records spanning the last 10 million years records in the southwest and northern parts of this basin show long term contrasting trends despite the fact that geochemical evidence for alteration is similar in both parts of the basin i e towards less alteration since 10 ma however contrasting clay mineral assemblages in the northern and southwestern areas do suggest long term changes in the relative climate of indochina and southern china we interpret this to reflect the northward migration of the itcz since the miocene resulting in a progressive drying of indochina and increasingly wet conditions in south china sediment believed to be supplied from the mekong river iodp site u1433 shows increasing chemical weathering at a time of long term drying of the climate this probably reflects increasing chemical weathering driven by slower transport and despite reduced rates of chemical alteration in the context of a colder drier climate since the miocene in general hematite goethite data are consistent with pollen constraints from the same drill site that show colder conditions with increasing hematite goethite since 3 ma and with a transition to apparently wetter conditions since the mid pleistocene transition mpt this implies that most of the sediment in the southwestern basin is weathered and eroded during warmer wetter interglacial phases at least since the mpt

uranium series chronology and environmental applications of speleothems an increasing number of scientists recognize the value of speleothems1 as often extremely well preserved archives of information about past climate vegetation hydrology sea level nuclide migration water rock interaction landscape evolution tectonics and human action well constrained data are required to document past changes reconstruct past patterns and predict future responses of the earth system at a wide range of spatial and temporal scales speleothems are particularly useful in this regard because they can be found in many locations of the globe sampled at high resolution and reliably dated using high precision uranium series techniques speleothems are bodies of mineral material formed in caves as the result of chemical precipitation from groundwater flowing or dripping in a cave most speleothems are composed of calcite formed by slow degassing of co2 from supersaturated groundwater but aragonite and gypsum forms are also common particularly near cave entrances where evaporative effects are important a host of different speleothem types decorate the walls ceilings and floors of caves and their mineralogy and morphology is a function of fluid flow and chemistry of waters feeding a particular location as well as the ambient conditions temperature chemistry light in the air or water filled void subaerial forms include the familiar stalagmites stalactites draperies flowstones subaqueous forms include rimstone pools rafts mammillary calcite wall coatings and dog tooth spar for an extensive review of the types of speleothem that have been observed see hill and forti 1997 speleothems are used in a multitude of ways to explore past environmental conditions perhaps the most fundamental of which is their very presence or absence deposition of speleothems relies on sufficient water supply and soil co2 to enable dissolution and transport of reactants in the vadose zone to underlying caves in arid or glacial times conditions may not have been favorable for speleothem formation

huge erratic boulders in tonga deposited by a prehistoric tsunami along some coastlines there are erratic boulders apparently emplaced by tsunamis or cyclonic storms evaluating their origin and time of emplacement places constraints on the frequency severity and location of coastal hazards seven such large coral limestone boulders are present near fahefa village on tongatapu island southwest pacific apparently emplaced by a prehistoric tsunami these boulders are 10 20 m above sea level and above any possible source and all are 100 400 m from the present shoreline coral 230th ages indicate that the limestone formed during the last interglacial sea level highstand ca 120 130 ka the largest boulder is 20 times more massive than any reported boulders emplaced by historically documented storms and may be the largest known tsunami or storm erratic worldwide situated above its source we performed computer simulations to assess whether tsunamis produced by earthquakes undersea landslides or volcanoes could emplace the boulders the simulations indicate that either volcanic flank collapse along the tofua arc 30 40 km to the southwest or undersea landslides on the submarine slopes of tongatapu could be responsible either could explain why these boulders are not widespread on tongatapu and instead occur in a localized group along the western coast this study demonstrates that small 1 km3 submarine slope failures sometimes generate locally large tsunamis the fahefa boulders are in a well studied and well populated area yet were unknown to the scientific community until recently this suggests that systematic searches elsewhere for erratic boulders and other tsunami deposits might provide new information for assessing the size and extent of prehistoric tsunamis

cave air control on dripwater geochemistry obir caves austria implications for speleothem deposition in dynamically ventilated caves there are very few process studies that demonstrate the annual variation in cave environments depositing speleothems accordingly we initiated a monitoring program at the obir caves an austrian dripstone cave system characterized by a seasonally changing air flow that results in a predictable pattern of high pco2 during summer and low pco2 in winter although similar seasonal changes in soil pco2 occur they are not directly connected with the changes in the subsurface since the dripwaters are fed from a well mixed source showing little seasonal variation cold season flushing by relatively co2 poor air enhances degassing of co2 in the cave and leads to a high degree of supersaturation of dripwater with regard to calcite forced calcite deposition during the cold season also gives rise to a pronounced pattern of synchronous seasonal variations in electrical conductivity alkalinity ph ca and 13cdic which parallel variations recorded in 13ccave air chemical components unaffected by calcite precipitation e g d 18o sio2 so4 lack a seasonal signal attesting to a long residence in the karst aquifer modeling shows that degassing of co2 from seepage waters results in kinetically enhanced c isotopic fractionation which contrasts with the equilibrium degassing shown from the soreq cave in israel the obir caves may serve as a case example of a dripstone cave whose seepage waters and speleothems show intra annual geochemical variability that is primarily due to chemical modification of the groundwater by a dynamic bidirectional subsurface air circulation

stable isotope variations in modern tropical speleothems evaluating equilibrium vs kinetic isotope effects applications of speleothem calcite geochemistry in climate change studies require the evaluation of the accuracy and sensitivity of speleothem proxies to correctly infer paleoclimatic information the present study of harrison s cave barbados uses the analysis of the modern climatology and groundwater system to evaluate controls on the c and o isotopic composition of modern speleothems this new approach directly compares the 18 o and 13 c values of modern speleothems with the values for their corresponding drip waters in order to assess the degree to which isotopic equilibrium is achieved during calcite precipitation if modern speleothems can be demonstrated to precipitate in isotopic equilibrium then ancient speleothems suitable for paleoclimatic studies from the same cave environment may also have been precipitated in isotopic equilib rium if modern speleothems are precipitated out of isotopic equilibrium then the magnitude and direction of the c and o isotopic offsets may allow specific kinetic and or equilibrium isotopic fractionation mechanisms to be identified carbon isotope values for the majority of modern speleothem samples from harrison s cave fall within the range of equilibrium values predicted from the combined use of 1 calcite water fractionation factors from the literature 2 measured temperatures and 3 measured 13 c values of the dissolved inorganic carbon of drip waters calcite samples range from 0 8 higher to 1 1 lower than predicted values the 13 c depletions are likely caused by kinetically driven departures in the fractionation between hco3 aq and caco3 from equilibrium conditions caused by rapid calcite growth 13 c enrichments can be accounted for by rayleigh distillation of the hco3 aq reservoir during degassing of 13 c depleted co2 modern speleothems from harrison s cave are not in o isotopic equilibrium with their corresponding drip waters and are 0 2 to 2 3 enriched in 18 o relative to equilibrium values 18 o variations in modern calcite are likely controlled by kinetically driven changes in the fractionation between hco3 aq and caco3 from equilibrium conditions to nonequilibrium conditions consistent with rapid calcite growth in contrast to 13 c 18 o values of modern calcite may not be affected by rayleigh distillation during degassing because co2 hydration and hydroxylation reactions will buffer the o isotopic composition of the hco3 aq reservoir if the effects of rayleigh distillation manifest themselves in the o isotopic system they will result in 18 o enrichment in the hco3

lead concentrations and isotope ratios in speleothems as proxies for atmospheric metal pollution since the industrial revolution abstract lead concentrations and isotope ratios from two speleothems from the han sur lesse cave in southern belgium were measured in order to study the ability of speleothems to act as archives of atmospheric pollution to address this aim we analyzed trace elemental al and pb compositions by la icp ms and icp ms as well as pb isotopes by mc icp ms the results help to identify three intervals characterized by particularly high enrichment of pb from 1880 to 1905 ad from 1945 to 1965 ad and from 1975 to 1990 ad the speleothem record shows similar changes as the known historical atmospheric pollution level in belgium lead isotope ratios discriminate between pb sources and confirm that coal and gasoline combustion combined with regional metallurgical activities were the predominant pb pollution sources in the stalagmites during the last 250 years this study opens possibilities to determine anthropogenic versus natural metal sources in well dated speleothem archives

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