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

a 780 year annually resolved record of indian ocean monsoon precipitation from a speleothem from south oman 1 meteorological records of monsoon rainfall in the indian ocean are generally less than 100 years long the relative brevity of these records makes it difficult to investigate monsoon variation on decadal and centennial timescales to determine what factors influence the intensity of rainfall on these timescales or to place possible changes in the twentieth century into a broader historical context development of a geologic proxy for rainfall that records annual variation in the monsoon over much longer time periods than are covered by instrumental records would be a significant step forward we have developed an annually resolved record of monsoon rainfall variation for the past 780 years based on annual layer thickness and stable isotope analyses of a laminated stalagmite from southern arabia our results show that monsoon variation over the past century is not outside of the range of the past 800 years decreasing monsoon rainfall over the past century is related to increasing sea surface temperature in the indian ocean spectral analyses of the record are dominated by cycles that are similar to those observed in records of solar activity on centurial timescales decadal to interannual cycles in the record appear to originate in the tropical pacific ocean index terms 3344 meteorology and atmospheric dynamics paleoclimatology 3354 meteorology and atmospheric dynamics precipitation 1854 1620 global change climate dynamics 3309 1699 global change general or miscellaneous keywords monsoon paleoclimate rainfall indian ocean speleothem oxygen isotopes

a three thousand year record of north atlantic climate annual band counting on three radiometrically dated stalagmites from nw scotland provides a record of growth rate variations for the last 3000 years over the period of instrumental meteorological records we have a good historical calibration with local climate mean annual temperature mean annual precipitation regional climate north atlantic oscillation and sea surface temperature sst strongest at 65 70 n 15 20 w although the correlation with the latter breaks down prior to the instrumental record this suggests that the climatic factors that force nw scottish climate and therefore our stalagmite growth varied through time and include winter nao strength the strength of the thermohaline circulation and possibly solar output spectral analysis was performed on the stalagmite growth rate time series a spectral frequency of 50 70 years is predominant in two stalagmites that were deposited from 1000 to 3000 bp a slightly longer frequency of 72 94 years is dominant from 1000 bp to present these are the same as that observed in ocean gcm output for the north atlantic region ssts our stalagmites provide high resolution precisely dated evidence of a similar periodicity predominating over the last 3000 years in a climate proxy record known to be sensitive to changes in forcing functions relevant to the north atlantic sector

the 2002 2003 el nino recorded in australian cave drip waters implications for reconstructing rainfall histories using stalagmites 1 a 30 month study of drip hydrochemistry from kooringa cave eastern australia revealed a clear geochemical response to the 2002 2003 el nino through the drought drip discharge fell to base flow drip ca2 concentrations fell by half and drip mg ca and sr ca increased in a co varying pattern calcite mg ca and sr ca predicted from drip waters displayed a marked increase through and just beyond the period of greatest moisture deficit the results suggest that stalagmites from shallow caves in drought sensitive eastern australia potentially preserve a valuable record of el nino la nina history

roles of forest bioproductivity transpiration and fire in a nine year record of cave dripwater chemistry from southwest australia forest biomass has the potential to significantly impact the chemistry and volume of diffuse recharge to cave dripwater via the processes of nutrient uptake transpiration and forest fire yet to date this role has been under appreciated in the interpretation of speleothem trace element records from forested catchments in this study the impact of vegetation is examined and quantified in a long term monitoring program from golgotha cave sw australia the contribution of salts from rain and dry deposition of aerosols and dissolved elements from soil mineral and bedrock dissolution to dripwater chemistry are also examined this study is an essential pre requisite for the future interpretation of trace element data from sw australian stalagmite records whose record of past environmental change will include alterations in these biogeochemical fluxes solute concentrations in dripwater vary spatially supporting the existence of distinct flow paths governed by varying amounts of transpiration as well as nutrient uptake by deeply rooted biomass applying principal components analysis we identify a common pattern of variation in dripwater cl mg k ca sr and si interpreted as reflecting increasing transpiration due to forest growth mass balance calculations show that increasing elemental sequestration into biomass has the largest impact on so4 providing an explanation for the overall falling dripwater so4 concentrations through time in contrast to the transpiration driven rising trend dominating other ions the long term rise in transpiration and nutrient uptake driven by increased forest bioproductivity and its impact on our dripwater chemistry is attributed to i the post fire recovery of the forest understorey after fire impacted the site in 2006 ce ii and or increased water and nutrient demand as trees in the overlying forest mature the impact of climate driven changes on the water balance is also examined finally the implications for interpreting sw australian speleothem trace element records are discussed

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

trace metal and carbon isotopic variations in cave dripwater and stalagmite geochemistry from northern borneo we investigate stalagmite trace metal ratios and carbon isotopic composition 13 c as potential paleoclimate proxies by comparing cave dripwaters stalagmites and bedrock composition from gunung mulu and gunung buda national parks in northern borneo a tropical rainforest karst site three year long biweekly time series of dripwater mg ca sr ca and 13 c from several drips at our site are not correlated with rainfall variability indicative of a relatively weak relationship between hydroclimate and dripwater geochemistry at our site however combining all of the dripwater geochemical data gathered over four field trips to our site n 300 samples we find that drips with highly variable mg sr ca have relatively invariable 18 o values close to the mean we hypothesize that increased residence times translate into reduced variance in dripwater 18 o through mixing in the epikarst as well as increased mg sr ca values through increased calcite precipitation in the epikarst mg ca sr ca and 13 c time series from three overlapping stalagmites that grew over the last 27 kyrs are characterized by strong centennial scale variations and bear little resemblance to previously published well reproduced 18 o time series from the same stalagmites the only shared signal among the three stalagmites geochemical time series is a relative decrease of 1 in 13 c from the last glacial maximum to the holocene consistent with a transition from savannah c4 to rainforest c3 conditions documented in nearby records taken together our study indicates that stalagmite mg sr ca ratios are poor indicators of hydroclimate conditions at our site while stalagmite 13 c exhibits some reproducible signals on glacial interglacial timescales

reconstruction of late holocene autumn winter precipitation variability in sw romania from a high resolution speleothem trace element record abstract we present the first high resolution trace element mg ca sr ca ba ca record from a stalagmite in southwestern romania covering the last 3 6 ka which provides the potential for quantitative climate reconstruction precise age control is based on three independent dating methods in particular for the last 250 yr where chemical lamina counting is combined with the identification of the 20th century radiocarbon bomb peak and 230th u dating long term cave monitoring and model simulations of drip water and speleothem elemental variability indicate that precipitation related processes are the main drivers of speleothem mg ca ratios calibration against instrumental climate data shows a significant anti correlation of speleothem mg ca ratios with autumn winter october to march precipitation r 0 61 p during the late holocene our data suggest a heterogeneous pattern of past regional winter hydroclimate in the carpathian balkan realm along with intermittent weakening of the dominant influence of north atlantic forcing in agreement with other regional paleo hydrological reconstructions the observed variability reveals periodically occurring strong nw se hydro climate gradients we hypothesize that this pattern is caused by shifts of the eastern edge of the area of influence of the nao across central eastern europe due to the confluence of north atlantic forcing and other climatic features such as the east atlantic western russia eawr pattern

transformation of enso related rainwater to dripwater δ18o variability by vadose water mixing speleothem oxygen isotopes 18o are often used to reconstruct past rainfall 18o variability and thereby hydroclimate changes in many regions of the world however poor constraints on the karst hydrological processes that transform rainfall signals into cave dripwater add significant uncertainty to interpretations of speleothem based reconstructions here we present several 6 5 year biweekly dripwater 18o time series from northern borneo and compare them to local rainfall 18o variability we demonstrate that vadose water mixing is the primary rainfall to dripwater transformation process at our site where dripwater 18o reflects amount weighted rainfall 18o integrated over the previous 3 10 months we document large interannual dripwater 18o variability related to the el nino southern oscillation enso with amplitudes inversely correlated to dripwater residence times according to a simple stalagmite forward model asymmetrical enso extremes produce significant offsets in stalagmite 18o time series given different dripwater residence times our study highlights the utility of generating multiyear paired time series of rainfall and dripwater 18o to aid interpretations of stalagmite 18o reconstructions

annual trace element variations in a holocene speleothem high resolution secondary ionization mass spectrometry sims analysis along the growth axis of a holocene speleothem from northern scotland reveals high frequency oscillations and longer term trends in mg ca sr ca and ba ca at the scale of the high frequency oscillations mg ca and sr ca display a well defined anticorrelation while sr ca and ba ca are positively correlated imaging of elemental ratios in two dimensions reveals that the high frequency signal is well preserved and laterally continuous across the sample tims 230th ages and annual ultraviolet luminescence banding provide chronological control and demonstrate that the high frequency cyclicity is annual trace element variations in speleothem calcite are a reflection of hydrochemical processes in the unsaturated zone overlying the cave supply effects and partitioning at the water calcite interface mg partitioning between water and calcite is temperature dependent calculations suggest that the annual mg ca oscillations may be caused by seasonal temperature changes however the longer timescale variations in mg ca are too great to be explained by this mechanism seasonal variations in water residence time in the unsaturated zone which reflect effective precipitation provide a more probable explanation for the observed annual oscillations and also explain the inverse relationship between mg ca and sr ca this record suggests that trace elements in speleothems have the potential to provide the high resolution insights into interannual palaeoclimatic variability required for assessment of general circulation models

anthropogenic impact records of nature for past hundred years extracted from stalagmites in caves found in the nanatsugama sandstone formation saikai southwestern japan abstract in the nanatsugama area saikai city nagasaki prefecture japan covered by paleogene calcareous sandstone the environmental change information for the past hundred years was extracted from growing stalagmites in two limestone caves their annual microbanding information was used for dating from the shimizu do cave stalagmites the vegetation change from forest to grassland during 1500 to 1700 could be read using the carbon isotope and mg ca ratios of the stalagmites before 1500 the stable carbon isotope ratios ranged from 9 to 10 which are characteristic of forest vegetation from 1600 to 1700 the stable carbon isotope ratio increased 13 c 2 suggesting a drastic change to grassland vegetation probably for the purpose of collecting grasses for agricultural use the increase in mg ca due to the reduction in the biomass from 1500 to 1700 also showed the vegetation change from forest to grassland a ryuo do cave stalagmite recorded the change in the so 4 2 concentration several times during the period from 1600 to 1900 in addition to the sulfate of sea salt origin the higher concentration and smaller 34 s of sulfate in the ryuo do cave drip water compared to those in the shimizu do cave drip water may be due to the oxidation of biogenic pyrite in the marine kamashikiyama tuff formation which covers the calcareous sandstone of the nanatsugama sandstone formation the oxidation of pyrite is promoted by the biological activity of sulfur oxidizing bacteria under oxic conditions indicating that the surface cover was repeatedly changed into non paddy fields the change in the so 4 2 concentration could then be related to the changes in the amount of the nagasaki prefecture coal production in the early 20th century and the china fossil fuel consumption in the late 20th century transported a long distance by a monsoon from the china continent thus the combination of annual microbanding information and the mg 2 and so 4 2 concentrations and c and s stable isotope ratios of the stalagmites made it possible to extract local and or global anthropogenic environmental changes in nature the records extracted in this way were in good agreement with those partially extracted from ancient documents ancient picture maps and topographical maps

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

advancements in the use of speleothems as climate archives abstract speleothems have become a cornerstone of the approach to better understanding earth s climatic teleconnections due to their precise absolute chronologies their continuous or semicontinuous deposition and their global terrestrial distribution we review the last decade of speleothem related research building off a similar review by mcdermott 2004 in three themes i investigation of global teleconnections using speleothem based climate reconstructions ii refinement of climate interpretations from speleothem proxies through cave monitoring and iii novel technical methods of speleothem based climate reconstructions speleothem records have enabled critical insight into the response of global hydroclimate to large climate changes this includes the relevant forcings and sequence of climatic responses involved in glacial terminations and recognition of a global monsoon response to climate changes on orbital and millennial time scales we review advancements in understanding of the processes that control speleothem 13 c values and introduce the idea of a direct atmospheric pco 2 influence we discuss progress in understanding kinetic isotope fractionation which with further advances may help quantify paleoclimate changes despite non equilibrium formation of speleothems this feeds into the potential of proxy system modeling to consider climatic hydrological and biogeochemical processes with the objective of quantitatively interpreting speleothem proxies finally we provide an overview of emerging speleothem proxies and novel approaches using existing proxies most recently technical advancements made in the measurement of fluid inclusions are now yielding reliable determinations of paleotemperatures

identifying short term and seasonal trends in cave drip water trace element concentrations based on a daily scale automatically collected drip water dataset abstract a 13 month long daily scale drip water dataset collected by an automatic water sampling device placed in a small cave in ireland provides evidence for seasonal shifts in hydrochemistry including a pulse of colloidally associated elements in the late summer ca sr mg na ba p cu zn rb y cs u th and pb concentrations of the collected water samples were determined and flow rates were also calculated alkali and alkali earth metals decreased in concentration during a summer water deficit whereas colloidally associated element concentrations increased during the same interval and spiked dramatically in the late summer early autumn the observed increase in colloidally associated element concentrations may have coincided with increased breakdown of soil organic material by microorganisms in the late summer early autumn which led to an increased flux of organic colloids in the drip water or it may relate to increased rates of dry deposition from cave air the decrease in alkali and alkali earth metal concentrations in the summer most likely resulted from the addition of dilute water linked to condensation of water vapor above the drip site drip water sr and p concentrations are anticorrelated and their variation over the study period resembles seasonal trends observed in stalagmite calcite at other sites because the sr minima and p maxima are interpreted as reflecting different phenomena increased proportion of condensation water relative to karst water and an increased flux of organic colloids respectively the relative timing of these two mechanisms in the past may explain the shifting polarity of their correlation observed in some stalagmite trace element records

controls on trace element sr mg compositions of carbonate cave waters implications for speleothem climatic records abstract at two caves clamouse s france and ernesto ne italy cave drip and pool waters were collected and sampled at intervals over a 2 3 year period mg ca and sr ca concentration ratios corrected for marine aerosols are compared with those of bedrocks and in some cases aqueous leachates of soils and weathered bedrocks cave waters do not lie along mixing lines between calcite and dolomite of bedrock carbonate but typically show enhanced and covarying mg ca and sr ca four factors are considered as controlling processes 1 the much faster dissolution rate of calcite than dolomite allows for the possibility of increase of mg ca if water rock contact times are increased during drier conditions a theoretical model is shown to be comparable to experimental leachates 2 prior calcite precipitation along a flow path is a powerful mechanism for generating enhanced and covarying mg ca and sr ca ratios this mechanism requires the solution to lose co 2 into pores or caverns 3 incongruent dolomite dissolution has only limited potential and is best regarded as two separate processes of dolomite dissolution and calcite precipitation 4 selective leaching of mg and sr with respect to ca is shown to be important in leachates from ernesto where it appears to be a phenomenon of calcite dissolution in general selective leaching can occur whenever ca is sequestered into precipitates due to freezing or drying of soils or if there is derivation of excess sr and mg from non carbonate species the ernesto cave has abundant water supply which in the main chamber is derived from a reservoir with year round constant p co 2 of around 10 2 4 and no evidence of calcite precipitation in the karst above the cave two distinct but overlying trends of enhanced and covarying mg ca and sr ca away from the locus of bedrock compositions are due to calcite precipitation within the cave and at a variable drip site due to enhanced selective leaching at slow drip rates mg enhancement in the first chamber is due to a more dolomitic bedrock and longer residence times the clamouse site has a less abundant water supply and presents geochemical evidence of prior calcite precipitation both in the cave and in overlying porous dolomite dedolomitized limestone bedrock initial p co 2 values as high as 10 1 are inferred experimental incubations of clamouse soils which generated enhanced p co 2 and precipitated caco 3 had compositions similar to the karst waters calcite precipitation is inferred to be enhanced in drier conditions hydrological controls on cave water chemistry imply that the trace element chemistry of speleothems may be interpretable in palaeohydrological terms drier conditions tends to promote not only longer mean residence times enhancing dolomite dissolution and hence mg ca but also enhances degassing and calcite precipitation leading to increased mg ca and sr ca

rainfall and hydrological controls on speleothem geochemistry during climatic events droughts and typhoons an example from seopdong cave republic of korea abstract a five year old 20 cm long soda straw sd 1 was analyzed geochemically to delineate the relationship between the geochemical record and climatic behavior the growing tip of the soda straw was marked on july 18 1999 and the sample was collected on july 16 2004 thus the growth period of this speleothem is well constrained during the five years the soda straw grew about 20 cm a mean growth rate of about 4 cm year fast growth rate of this speleothem enabled not only to understand seasonal variations of geochemical data but also to compare these data directly with outside climatic variations near the cave 210 pb ex excess or unsupported 210 pb results suggest that the overall pattern of 210 pb ex changes as well as the frequency and relative intensity of their peaks show a strikingly similar pattern to that of the amounts of precipitation in the study area this suggests that 210 pb ex was transported into the cave with infiltrating rainwater mostly during rainy summers because 210 pb ex is a particle reactive element controlling detailed growth rates by the 210 pb ex fluctuations it can be noticed that 18 o compositions vary very little in spite of significant droughts and typhoon events whereas 13 c values clearly display impacts of a severe drought from 2000 to 2001 the sr ca ba ca u ca and mn ca ratios coincide with the 13 c trends and show anomalies during the drought period these coeval trends strongly indicate that hydraulic factors in vadose zone that were directly controlled by the amount of rainfall influenced on the geochemical imprints of the sd 1 this study illustrates the behavior of an atmospheric radionuclide 210 pb ex the o and c stable isotopes and trace elements in calcite speleothems and furthermore implies that they can be used to detect short term climatic behavior including climatic extreme events as well as the long term climatic fluctuations in the past

characteristics of the october 2005 microearthquake swarm and reactivation of similar event seismic swarms over decadal time periods near socorro new mexico seismicity in the rio grande rift in central new mexico southwestern united states has been dominated by microearthquakes occurring above the midcrustal socorro magma body smb for at least the past century the smb is a sill like feature 3400 km2 in area with a top surface at 19 km depth and centered below the inner rift half graben system a recent swarm of microearthquakes above the magma body began on 20 october 2005 the activity intensified toward 30 october 2005 with the largest event being a shallow felt local magnitude m l 2 4 earthquake at 02 57 35 utc seismicity increased in the region following this event with over 1600 earthquakes detectable at a minimum of one local seismic station during the subsequent month seismic waveforms for the earthquakes in this sequence are remarkably similar implying consistently similar location and faulting geometry the time space distribution of earthquakes indicates that this sequence is highly swarmlike in contrast to tectonic mainshock aftershock sequences given the local tectonic setting and shallow 8 km depth of individual events above the smb a likely explanation for the socorro earthquake sequence is fluid flow or pressure induced triggering associated with the evolution of the smb swarms such as the 2005 sequence are not uncommon in this area e g prominent previous sequences occurred in may and july of 1983 here we characterize the 2005 earthquake sequence by presenting composite focal mechanisms magnitude estimates and high precision relative locations based on waveform cross correlation techniques that capitalize on the similar waveforms a new waveform scanning technique identifies over 1600 small similar earthquakes during this period from continuous seismic records waveforms and locations are also observed to be similar between the 2005 and 1983 sequences suggesting consistency in source location geometry and thus mechanism over decadal time scales

reconstructing el nino southern oscillation enso from high resolution palaeoarchives el nino southern oscillation enso is one of the most important coupled ocean atmospheric phenomena to cause global climate variability on interannual timescales efforts to understand recent apparently anomalous enso behaviour are hampered by the phenomenon s unstable non stationary nature and the limitations inherent in palaeoclimate records in this paper the complexities associated with isolating enso signals in observational and palaeoclimate records are reviewed the utility and limitations of high resolution tree ring coral speleothems ice and documentary proxy data for enso reconstruction are discussed to overcome the regional biases contained within each palaeoclimatic source it is necessary to compare complementary signals derived from multiple proxy climate records to date there have been limited attempts to reconstruct large scale enso using these multiproxy methodologies a critique of the complexities associated with previous approaches of reconstructing discrete enso events and atmospheric oceanic indices is provided abundant potential remains to better characterise teleconnection patterns propagation signatures and non stationary features of large scale enso behaviour if key uncertainties in enso dynamics such as the response of extreme events to natural human forcing are to be adequately assessed then complementary attempts must be made to model the historic synoptic conditions with apparent changes in reconstructed indices copyright 2006 john wiley sons ltd

impacts of cave air ventilation and in cave prior calcite precipitation on golgotha cave dripwater chemistry southwest australia abstract speleothem trace element chemistry is an important component of multi proxy records of environmental change but a thorough understanding of hydrochemical processes is essential for its interpretation we present a dripwater chemistry dataset pco2 alkalinity ca sicc mg and sr from an eight year monitoring study from golgotha cave building on a previous study of hydrology and dripwater oxygen isotopes treble et al 2013 golgotha cave is developed in quaternary aeolianite and located in a forested catchment in the mediterranean type climate of southwest western australia all dripwaters from each of the five monitored sites become supersaturated with respect to calcite during most of the year when cave ventilation lowers pco2 in cave air in this winter ventilation mode prior calcite precipitation pcp signals of increased mg ca and sr ca in dripwater are attributed to stalactite deposition a fast dripping site displays less evolved carbonate chemistry implying minimal stalactite growth phenomena which are attributed to minimal degassing because of the short drip interval 30 s we employ hydrochemical mass balance modelling techniques to quantitatively investigate the impact of pcp and co2 degassing on our dripwater initially we reverse modelled dripwater solutions to demonstrate that pcp is dominating the dripwater chemistry at our low flow site and predict that pcp becomes enhanced in underlying stalagmites secondly we forward modelled the ranges of solution mg ca variation that potentially can be caused by degassing and calcite precipitation to serve as a guide to interpreting the resulting stalagmite chemistry we predict that stalagmite trace element data from our high flow sites will reflect trends in original dripwater solutes preserving information on biogeochemical fluxes within our system by contrast stalagmites from our low flow sites will be dominated by pcp effects driven by cave ventilation our poorly karstified system allows us to highlight and quantify these in cave pcp processes which are otherwise masked at sites where karstification is more developed and hydrogeology is more complex our modelling also shows enhanced co2 source production in the unsaturated zone that is attributed to deeply rooted vegetation and increasing bioproductivity which we link to forest recovery after fires impacted our site during 2006 ce

meteorological causes of harmattan dust in west africa we investigated the temporal dynamics of dust entrainment in the bodele depression central sahara to better understand the intra annual variability of aerosol emission in the world s largest dust source the linkages between dust entrainment and large scale meteorological factors were examined by correlating several meteorological variables in the mediterranean and africa north of the equator with the aerosol concentrations in the bodele depression separately for winter and summer the methodological tools applied are ncep ncar reanalysis data and the aerosol index of the total ozone mapping spectrometer toms ai available for 15 years from 1978 to 1993 we found that dust mobilisation during the harmattan season is highly dependent on air pressure variability in the mediterranean area high pressure to the north of the bodele intensifies the ne trade winds leading to an increased entrainment of dust in the bodele depression in summer dust mobilization cannot be explained by the large scale meteorological conditions this highlights the importance of local to regional wind systems linked to the northernmost position of the intertropical convection zone itcz during this time

timing and nature of the penultimate deglaciation in a high alpine stalagmite from switzerland abstract the timing and nature of the penultimate deglaciation also known as termination ii t ii is subject of controversial discussions due to the scarcity of precisely dated palaeoclimate records here we present a new precisely dated and highly resolved multi proxy stalagmite record covering t ii from the high alpine schafsloch cave in switzerland an area where climate is governed by the north atlantic the inception of stalagmite growth at 137 4 1 4 kyr before present bp indicates the presence of drip water and cave air temperatures of above 0 c and is related to a climate induced change in the thermal state from cold to warm based of the glacier above the cave the cessation of stalagmite growth between 133 1 0 7 and 131 9 0 6 kyr bp is most likely related to distinct drop in temperature associated with heinrich stadial 11 the resumption of stalagmite growth at 131 9 0 6 kyr bp is accompanied by an abrupt increase in temperature and precipitation as indicated by distinct shifts in the oxygen and carbon isotopic composition as well as in trace element concentrations the mid point of t ii is around 131 8 0 6 kyr bp in the schafsloch cave record is significantly earlier compared to the age of 129 1 0 1 kyr bp in the sanbao cave record from china the different ages between both records can be best explained by the competing effects of insolation and glacial boundary forcing on seasonality and snow cover extent in eurasia

soil and karst aquifer hydrological controls on the geochemical evolution of speleothem forming drip waters crag cave southwest ireland abstract in recent years there has been increased interest in cave speleothems as archives of palaeoclimate monitoring of rainfall and soil and karst water chemistries was performed at crag cave castleisland co kerry southwest ireland in august 1997 and january 1998 in order to understand temporal and spatial variations in karst water hydrology and chemistry and their implications for interpreting the potential palaeohydrological signal preserved by speleothems at this site temporal variations in karst water drip rates and geochemistry allow drips to be classified by hydrological response to rainfall and the associated processes of dilution piston flow source change and prior calcite precipitation during aquifer throughflow evolution from soil matrix and preferential flow solutions has also been determined to exert an important control on karst water chemistries as a result of these findings we present hydrogeochemical models and plumbing diagrams that delineate the controls on karst water evolution at a number of sampling locations within the cave at this site we propose that a palaeohydrological signal may be recorded by crag cave speleothems that may be interpreted via the study of mg ca ratios in speleothems linked to monitoring of modern drip water chemistry

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

spatial variability in cave drip water hydrochemistry implications for stalagmite paleoclimate records the identification of vadose zone hydrological pathways that most accurately transmit climate signals through karst aquifers to stalagmites is critical for accurately interpreting climate proxies contained within individual stalagmites a three year cave drip hydrochemical study across a spectrum of drip types in crag cave sw ireland reveals substantial variability in drip hydrochemical behaviour stalagmites fed by very slow drips 2 ml min sites apparently unconnected with local meteorological events water from these drips was typically undersaturated with respect to calcite and thus did not result in calcite deposition data presented here suggest that drips in this flow regime also experience flow re routing and blocking and that any stalagmites developed under such drips are unsuitable as mid to high resolution paleoclimate proxies most drip sites demonstrated seasonal ca2 and mg2 variability that was probably linked to water excess prior calcite precipitation along the flowpath affected the chemistry of slowly dripping sites while dilution predominantly controlled the water chemistry of the more rapidly dripping sites this research underscores the importance of understanding drip hydrology prior to selecting stalagmites for paleoclimate analysis and before interpreting any subsequent proxy data

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

a stepwise screening system to select storm sensitive stalagmites taking a targeted approach to speleothem sampling methodology a stepwise stalagmite sample screening process was applied in order to select a stalagmite as a sensitive recorder of recent tropical cyclone rainfall events near belize field and laboratory criteria were combined in series to screen out candidate stalagmites whose characteristics indicated lower sensitivity to stormwater infiltration the approach described here was designed to increase the likelihood that selected stalagmites would increase the signal noise ratio of the target phenomenon in the resulting proxy records this four stage method for sample selection may be an important methodological consideration for researchers attempting to use speleothems for stable isotope paleotempestology hallmarks of this approach include 1 establishing a priori scientific targets 2 applying sample criteria in the form of contra indicators and 3 organizing the sample screening protocol into a series of practical stages the overall approach to stalagmite selection presented here supports cave conservation and can be adapted readily by others in support of different scientific goals it is hoped that other investigators will also publish field and laboratory sample selection schemes as increased transparency will provide new information invaluable to replication efforts and to advancing the field of speleothem paleo environmental studies

climate influence on geochemistry parameters of waters from santana perolas cave system brazil abstract a four year study of water geochemistry and hydrology was performed in a relatively deep cave system overlying bedrock thickness varies from 100 to 300 m as part of two monitoring programs from june 1990 to february 1992 and from march 2000 to march 2002 the ph saturation index for calcite ca and so 4 concentrations and elemental ratios of mg ca and sr ca were measured in surface well and drip waters throughout the system despite local hydrological and geological differences among sampling sites the monitoring revealed significant synchronous intersite variations in these parameters that are related to seasonal changes in rainfall recharge suggesting that element ratios of speleothems formed in deep caves are capable of recording short term climate variations groundwater residence time appears to be the main factor affecting the water composition in the epikarst epikarstic waters are always undersaturated with respect to calcite but both saturation index s i and dissolved solids content increase substantially during drier periods because of longer residence times and longer interaction between meteoric water and limestone by contrast results from cave drips and rimstone pools indicate constant supersaturation for calcite and demonstrate that a major control on trace element ratios of waters in the deep vadose zone is the degree of prior calcite precipitation this mechanism is more effective during drier periods when higher mg ca and sr ca values are observed in all drip and pool sites however variations do occur independently of the general trend of drip discharge which suggest non linear features in cave seepage water geochemistry in addition synchronous variations in so 4 and cl concentration indicate high connectivity between different water flow pathways characterized by similar response to interseasonal changes in vadose water level fluctuations in trace element ratios of cave streams appear to reflect increased contribution of waters flushed from the vadose fissure aquifer during very wet periods by a piston flow mechanism flushing episodes are also responsible for maintaining more positive saturation indices in streams even during periods of high river discharge our results suggest that trace elements are a potential proxy for past rainfall changes but they also reveal different scenarios for interpreting trace elements ratios of speleothems and freshwater tufa deposited in a deep cave systems located in tropical humid areas

the significance of chemical isotopic and detrital components in three coeval stalagmites from the superhumid southernmost andes 53 s as high resolution palaeo climate proxies abstract stalagmites are important palaeo climatic archives since their chemical and isotopic signatures have the potential to record high resolution changes in temperature and precipitation over thousands of years we present three u th dated records of stalagmites ma1 ma3 in the superhumid southern andes chile 53 s they grew simultaneously during the last five thousand years ka bp in a cave that developed in schist and granodiorite major and trace elements as well as the c and o isotope compositions of the stalagmites were analysed at high spatial and temporal resolution as proxies for palaeo temperature and palaeo precipitation calibrations are based on data from five years of monitoring the climate and hydrology inside and outside the cave and on data from 100 years of regional weather station records water insoluble elements such as y and hree in the stalagmites indicate the amount of incorporated siliciclastic detritus monitoring shows that the quantity of detritus is controlled by the drip water rate once a threshold level has been exceeded in general drip rate variations of the stalagmites depend on the amount of rainfall however different drip water pathways above each drip location gave rise to individual drip rate levels only one of the three stalagmites ma1 had sufficiently high drip rates to record detrital proxies over its complete length carbonate compatible element contents e g u sr mg which were measured up to sub annual resolution document changes in meteoric precipitation and related drip water dilution in addition these soluble elements are controlled by leaching during weathering of the host rock and soils depending on the ph of acidic pore waters in the peaty soils of the cave s catchment area in general higher rainfall resulted in a lower concentration of these elements and vice versa the mg ca record of stalagmite ma1 was calibrated against meteoric precipitation records for the last 100 years from two regional weather stations carbonate compatible soluble elements show similar patterns in the three stalagmites with generally high values when drip rates and detrital tracers were low and vice versa 13c and 18o values are highly correlated in each stalagmite suggesting a predominantly drip rate dependent kinetic control by evaporation and or outgassing only c and o isotopes from stalagmite ma1 that received the highest drip rates show a good correlation between detrital proxy elements and carbonate compatible elements a temperature related change in rainwater isotope values modified the ma1 record during the little ice age 0 7 0 1 ka bp that was 1 5 c colder than today the isotopic composition of the stalagmites ma2 and ma3 that formed at lower drip rates shows a poor correlation with stalagmite ma1 and all other chemical proxies of ma1 hendy tests indicate that the degassing controlled isotope fractionation of ma2 and ma3 had already started at the cave roof especially when drip rates were low changing pathways and residence times of the seepage water caused a non climatically controlled isotope fractionation which may be generally important in ventilated caves during phases of low drip rates our proxies indicate that the neoglacial cold phases from 3 5 to 2 5 and from 0 7 to 0 1 ka bp were characterised by 30 lower precipitation compared with the medieval warm period from 1 2 to 0 8 ka bp which was extremely humid in this region

evidence for holocene changes in australian indonesian monsoon rainfall from stalagmite trace element and stable isotope ratios abstract trace element and stable isotope ratios from an active stalagmite lr06 b1 recovered from liang luar cave on the island of flores eastern indonesia are used to reconstruct the position of the austral summer inter tropical convergence zone and australian indonesian summer monsoon variability during the holocene uranium series dating of the stalagmite shows that it commenced growth 12 640 years ago with hiatuses spanning 8 560 to 6 420 and 3 670 to 2 780 years ago stalagmite mg ca and sr ca ratios correlate significantly with one another and with 18 o and 13 c throughout the record this suggests that the mg ca and sr ca ratios are dominated by prior calcite precipitation a process whereby degassing in the vadose zone during periods of low recharge causes deposition of calcite and disproportionate loss of ca 2 ions relative to mg 2 and sr 2 upstream of the stalagmite the degree of initial 234 u 238 u disequilibrium also appears to have been controlled by recharge to the overlying aquifer together with the mg ca sr ca and 18 o values the initial uranium isotope activity ratios 234 u 238 u i imply a generally drier early holocene coincident with a lower sea level and lower southern hemisphere summer insolation comparison of speleothem 18 o time series from flores and borneo shows that they vary in unison for much of the holocene however there is a significant decrease in the borneo 18 o record 6 000 to 4 000 years ago that does not occur in the flores record this anomaly may be related to a change in the australian indonesian summer monsoon circulation in response to a protracted positive phase of the indian ocean dipole under this scenario stronger upwelling off of western indonesia would based on present day effects result in reduced summer convective activity over flores and a subsequent northward shift of the intertropical convergence zone

i stal a model for interpretation of mg ca sr ca and ba ca variations in speleothems and its forward and inverse application on seasonal to millennial scales 1 trace element ratios mg ca sr ca and ba ca are readily measured in speleothems and may be closely related to hydrological balance enhancing paleoclimate information inferred from stable isotope measurements we develop a model which simulates the variation in dripwater chemistry resulting from variable degree of water rock interaction and prior calcite precipitation pcp with the latter process depending both on drip interval and drip oversaturation with respect to caco3 partition coefficients between speleothem and dripwater are dependent on temperature for mg and on speleothem growth rate for sr and ba as observed in laboratory experiments the drip oversaturation state regulated both by cave pco2 and the dilution and soil karst dissolution processes strongly affects stalagmite trace element concentrations by modulating the extent of pcp and speleothem growth rates application of an inverse model confirms that seasonal co2 cycles can explain the uncorrelated seasonal cycles in mg ca and sr ca observed in our speleothem records from nw spain for which high co2 coincides with dry season in absence of seasonal variations in drip interval cycles in cave pco2 can produce seasonal covariation in sr ca mg ca and ba ca in long time series 104 yr where seasonal sampling resolution is not obtained in stalagmites a change from dominance of summer to winter rainfall can shift the season of strongest stalagmite deposition to one of lower mean co2 and hence greater pcp and higher mg ca sr ca and ba ca ratios caves best suited to record a dominantly water balance signal such as mean drip intervals are those with minimal seasonal variation in cave pco2

speleothem trace element signatures a hydrologic geochemical study of modern cave dripwaters and farmed calcite trace element variations in ancient cave speleothems are often interpreted as indicators of changes in paleo rainfall and hydrologic conditions however these records are difficult to interpret without an understanding of the physicochemical controls on stalagmite chemistry plus site specific calibration of changes in net rainfall to variations in dripwater and speleothem chemistry in this study we examine geochemical relationships between net rainfall precipitation minus evapotranspiration p et drip rates drip water chemistry and contemporaneous calcite chemistry to test the hypothesis that speleothem mg ca and sr ca records are proxies for rainfall amount hrc is contained within four low magnesium limestone units capped sporadically by a remnant dolomitic limestone aqueous concentrations of magnesium post evapotranspiration decrease with increasing vertical travel distance between the soil zone and the point of in cave drip emergence drip path length dpl as dissolved high mg solutions sourced from the dolomitic caprock are diluted with dissolved low mg limestone waters sourced from the host limestone dripwater mg ca and sr ca ratios covary and provide diagnostic indicators of the two dominant mechanisms controlling dripwater chemistry 1 mixing of post evaporative solutions derived from two geochemical endmembers dissolution of dolomite and limestone and 2 evolution of hydrochemistry away from dissolved bedrock compositions due to prior calcite precipitation pcp above the drip sites by resolving the linear mixing relationships for drip water mg ca and sr ca sources and the distribution coefficients for trace element transfer in the pcp dripwater to calcite precipitation reactions and applying these principles to our time series we find that the extent of pcp production within the karst is directly controlled by the balance between precipitation p and evapotranspiration et higher net rainfall p et 1 wet conditions reduces pcp and lower net rainfall with increased evapotranspiration p et 1 increases pcp farmed calcite x ca ratios faithfully track hydrologically influenced seasonal variations in dripwater chemistry for x mg sr and na however the relationship between changes in net rainfall and changes in mg ca and sr ca ratios in modern calcite is unique at each site and differs significantly at closely spaced drip stalagmite locations this suggests that in situ modern hydrochemical calibrations should be performed atop individual speleothems prior to harvesting for paleoclimate investigations and that such calibrations may not reflect past conditions as drip paths change we apply this understanding to published dripwater data and speleothem time series from other caves a major implication is that in order to interpret stalagmite sr ca and mg ca ratios as wet vs dry proxies speleothem sr ca and mg ca variations must be coherent and in phase over all time periods i e sr mg ratios must be constant these criteria will help to distinguish rainfall amount versus rainfall source in speleothem 18o records

partitioning of mg sr ba and u into a subaqueous calcite speleothem abstract the trace element geochemistry of speleothems is becoming increasingly used for reconstructing palaeoclimate with a particular emphasis on elements whose concentrations vary according to hydrological conditions at the cave site e g mg sr ba and u an important step in interpreting trace element abundances is understanding the underlying processes of their incorporation this includes quantifying the fractionation between the solution and speleothem carbonate via partition coefficients where the partitioning d of element x dx is the molar ratio x ca in the calcite divided by the molar ratio x ca in the parent water and evaluating the degree of spatial variability across time constant speleothem layers previous studies of how these elements are incorporated into speleothems have focused primarily on stalagmites and their source waters in natural cave settings or have used synthetic solutions under cave analogue laboratory conditions to produce similar dripstones however dripstones are not the only speleothem types capable of yielding useful palaeoclimate information in this study we investigate the incorporation of mg sr ba and u into a subaqueous calcite speleothem cd3 growing in a natural cave pool in italy pool water measurements extending back 15 years reveal a remarkably stable geochemical environment owing to the deep cave setting enabling the calculation of precise solution x ca we determine the trace element variability of modern subaqueous calcite from a drill core taken through cd3 to derive dmg dsr dba and du then compare these with published cave cave analogue and seawater analogue studies the dmg for cd3 is anomalously high 0 042 0 002 compared to previous estimates at similar temperatures 8 c the dsr 0 100 0 007 is similar to previously reported values but data from this study as well as those from tremaine and froelich 2013 and day and henderson 2013 suggest that na sr might play an important role in sr incorporation through the potential for na to outcompete sr for calcite non lattice sites dba in cd3 0 086 0 008 is similar to values derived by day and henderson 2013 under cave analogue conditions whilst du 0 013 0 002 is almost an order of magnitude lower possibly due to the unusually slow speleothem growth rates

evidence for solar influence in a holocene speleothem record pere noel cave se belgium abstract we present a decadal centennial scale holocene climate record based on trace elements contents from a 65 cm stalagmite from belgian pere noel cave pere noel pn stalagmite covers the last 12 7 ka according to u th dating high spatial resolution measurements of trace elements sr ba and mg were done by laser ablation inductively coupled plasma mass spectrometry la icp ms trace elements profiles were interpreted as environmental and climate changes in the han sur lesse region power spectrum estimators and continuous wavelet transform were applied on trace elements time series to detect any statistically significant periodicities in the pn stalagmite spectral analyses reveal decadal to millennial periodicities i e 68 75 133 136 198 209 291 358 404 602 912 1029 and 2365 2670 yr in the speleothem record results were compared to reconstructed sunspot number data to determine whether solar signal is presents in pn speleothem the occurrence of significant solar periodicities i e cycles of gleissberg de vries unnamed 500 years eddy and hallstatt supports for an impact of solar forcing on pn speleothem trace element contents moreover several intervals of significant rapid winter change were detected during the holocene at 10 3 9 3 9 5 around 8 2 6 4 6 2 4 7 4 5 and around 2 7 ka bp those intervals are similar to the cold winter events evidenced in different natural paleoclimate archives suggesting common climate forcing mechanisms related to changes in solar irradiance

evidence of rainfall variations in southern brazil from trace element ratios mg ca and sr ca in a late pleistocene stalagmite trace element ratios in the bt2 stalagmite from botuveracave southern brazil are explored as a proxy for changes in the local rainfall recharge during the last 116 ky bp mg ca and sr ca ratios measured with an electron microprobe are signif icantly positively correlated with one another throughout the entire record and vary in a way that is very consistent with variations of d 18 o in the same speleothem during the last glacial period we suggest that prior calcite precipitation in the vadose zone of the cave system is the main factor affecting the incorporation of mg and sr into calcite of the stalagmite this interpretation is supported by trace element correlation patterns and by results from a hydrochemistry study performed in a cave located in the same region and in a similar environmental setting therefore we conclude that higher lower mg ca and sr ca values are associated with lower higher levels of recharge into the karstic aquifer as such conditions lead to an increase decrease in the volume of calcite precipitated in the unsaturated zone above the cave during dry wet climate periods trace element variations point to generally dryer wetter conditions during lower high phases of summer insolation in the southern hemisphere these periods coincide with decreased increased activity of the south american summer monsoon as revealed by d 18 o stalagmite records in addition trace element variations show that rather wet conditions persisted through out most of the last glacial period from approximately 70 to 17 ky bp we suggest that during this period the glacial boundary conditions especially ice volume buildup in the northern hemisphere played an important role for monsoon rainfall inten sification in the region 2007 elsevier ltd all rights reserved

hydrology of cave drip waters at varying bedrock depths from a karst system in southeastern australia the study of how cave drip water discharge responds to recharge events is fundamental to evaluating the potential of actively forming speleothems as high resolution climate archives most previous research has focused on caves of the northern hemisphere middle latitudes where recharge is strongly seasonal few studies have explored drip water behaviour from regions where the expected seasonal rainfall pattern is significantly perturbed on an irregular basis by changing regional atmospheric circulation patterns here we report the results of a 4 year study of cave drip water climate relationships from two caves in eastern australia the discharge of 10 drip sites located beneath bedrock thicknesses of 12 22 and 45 m was monitored either continuously using automated infrared sensors or at discrete approximately monthly intervals and compared with local rainfall and water balance data the study period traversed two major droughts including the severe 2002 2003 el nino drips at 12 and 22 m depths responded almost simultaneously to individual recharge events although the time lag between individual events varied according to the volume of recharge and pre event storage overall a steady decline in discharge is evident through the moisture deficit period with increased flows through phases of positive water balance speleothems growing at these and similar shallow chamber sites have potential for reconstructing palaeo rainfall trends at high resolution although the highly variable nature of year to year recharge would make it difficult to obtain data on a calendrical time scale drips at 45 m depth did not respond consistently to individual recharge events and displayed hydrological behaviour markedly dissimilar to one another and to the near surface drip sites indicating great complexity in karst architecture and the absence of fissure flow although speleothems at this depth may well preserve information on longer term rainfall trends their potential to encode a palaeo rainfall variability signal at interannual resolution is poor copyright 2007 john wiley sons ltd

an isotopic and modelling study of flow paths and storage in quaternary calcarenite sw australia implications for speleothem paleoclimate records abstract we investigated the distinctive shallow sub surface hydrology of the southwest western australia swwa dune calcarenite using observed rainfall and rainfall 18 o soil moisture cave drip rate and dripwater 18 o over a six year period august 2005 march 2012 a lumped parameter hydrological model is developed to describe water fluxes and drip 18 o comparison of observed data and model output allow us to assess the critical non climatic karst hydrological processes that modify the precipitation 18 o signal and discuss the implications for speleothem paleoclimate records from this cave and those with a similar karst setting our findings include evidence of multiple reservoirs characterised by distinct 18 o values and recharge responses low and high flow sites dripwaters exhibit 18 o variations in wet versus dry years at low flow sites receiving diffuse seepage from the epikarst with an attenuated isotopic composition that approximates mean rainfall recharge from high magnitude rain events is stored in a secondary reservoir which is associated with high flow dripwater that is 1 lower than our monitored low flow sites 18 o one drip site is characterised by mixed flow behaviour and exhibits a non linear threshold response after the cessation of drainage from a secondary reservoir following a record dry year 2006 additionally our results yield a better understanding of the vadose zone hydrology and dripwater characteristics in quaternary age dune limestones we show that flow to our monitored sites is dominated by diffuse flow with inferred transit times of less than one year diffuse flow appears to follow vertical preferential paths through the limestone reflecting differences in permeability and deep recharge into the host rock

dating cave drip water by tritium summary speleothems are increasingly used as an archive of past climate but some of the proxy signals encoded in these deposits reflect hydrological characteristics of the karst aquifer and not necessarily climate variability a central aspect in karst hydrology is the time required for the rainwater to reach the point of discharge in a cave e g the tip of the stalactite one promising approach in determining this residence time is drip water dating by tritium 3 h in contrast to traditional tritium dating we do not refer directly to tritium concentrations in precipitation as input function but to an infiltration weighted annual mean of the rainwater values using concentration differences between this infiltration weighted mean and the drip water an age is calculated from the radioactive decay law assuming piston flow the approach was tested in three adjacent caves in northwestern germany which were monitored for about two years all of the studied drip sites yielded drip water ages between 2 and 4 years with uncertainties on the order of 1 year these results were confirmed at several drip sites by oxygen isotope data which show rather constant values with insignificant intra annual variability attempts to apply the 3 h 3 he method resulted in comparable ages despite several complicating factors

magnesium and strontium systematics in tropical speleothems from the western pacific abstract we present bulk average sr and mg data for 13 speleothems from different locations in the western equatorial pacific guam solomon islands and vanuatu these data plot on a single straight line in a graph of ln sr ca vs ln mg ca with a slope of 0 9 a 22 000 year record of sr and mg in one of these samples from guam also plots with the same slope suggesting that the process partitioning mg and sr within the guam speleothem is the same as the one that partitions mg and sr between the different pacific speleothems we rule out temperature growth rate detrital phases and sea spray as likely mechanisms for this correlation we construct mathematical models of limestone diagenesis and show that this cannot explain the slope of the correlation our favoured explanation for the correlation is calcite water interaction in the form of prior calcite precipitation pcp and or incongruent calcite dissolution icd we present a formal mathematical model of pcp and prove that the slope of a graph of ln sr ca and ln mg ca is given by kd sr 1 kd mg 1 a similar equation is derived for icd in a companion paper sinclair 2011 using published values for kdsr and kdmg this slope is calculated to be 0 88 in excellent agreement with our observations because the slope is independent of solution and host limestone composition it can be used to diagnose calcite water interaction in individual cave water studies where host rock composition is unknown or in speleothems for which no field drip water data or host rock geochemistry exists approximately half of published drip and speleothem mg sr studies plot within error of this slope we hypothesize that the overall trend in our pacific speleothem data results from the individual dripwater systems evolving from a roughly similar initial rock composition set by late quaternary reef limestone in the guam speleothem the broad peak in mg and sr centred on the early mid holocene reflects a change in hydrology rainfall with the most likely scenario being that dry conditions prevailed on guam at this time

inconsistency between records of δ18o and trace element ratios from stalagmites evidence for increasing mid late holocene moisture in arid central asia the interpretation of trace element calcium ratios of speleothems as indicators of local hydroclimatic variability in the vicinity of caves has led to controversy in reconstructing the evolution of

annual to sub annual resolution of multiple trace element trends in speleothems this study aims to establish evidence for the widespread existence of preserved high resolution trace element variations in speleothems that may have climatic significance ion microprobe analysis of speleothems reveals that annual to sub annual variations in element chemistry exist at five shallow western european cave sites crag cave county kerry and ballynamintra county waterford ireland uamh an tartair sutherland scotland grotte pere noel belgium grotta di ernesto ne italy with widely varying climatic geomorphic and geological settings the variations are not restricted to species mg sr and ba known to substitute directly for ca in the calcite lattice but include h f na and p phosphorus as phosphate displays the greatest variability and may have the most significance as a proxy for the seasonal temperature cycle because of its role as a nutrient element the technique allows estimation of growth rate of speleothems at any interval of interest which is one of several possible uses in palaeoclimatology

regional scale climate influences on temporal variations of rainwater and cave dripwater oxygen isotopes in northern borneo this study investigates the relationship between large scale climate variability rainfall oxygen isotopic composition 18 o and cave dripwater 18 o at gunung mulu and gunung buda national parks in northern borneo 4 n 115 e on intraseasonal to interannual timescales a 3 yr timeseries of rainfall 18 o contains prominent seasonal and interannual variability the seasonal cycle in rainfall 18 o is defined by lighter values of 10 during late boreal summer and heavier values of 4 during late boreal winter and is poorly correlated to local precipitation which displays very weak seasonality seasonally varying moisture trajectories likely play a key role in the observed seasonal cycle of rainfall 18 o driving enhanced fractionation during boreal summer and less fractionation during boreal winter dripwater 18 o timeseries display 2 seasonal cycles that follow the rainfall 18 o seasonal cycles with a mean 18 o value equivalent to the mean 18 o of rainfall large surveys of cave dripwaters conducted during three fieldtrips to gunung mulu buda reveal a system wide response to rainfall 18 o seasonality that supports a relatively short less than 6months response time for most drips during the weak 2005 2006 la nina event sustained positive precipitation anomalies are associated with rainfall 18 o values that are 4 to 5 lighter than previous years values consistent with the tropical amount effect observed in both models and data dripwater 18 o values are 1 to 2 lighter during the weak la nina event the importance of the amount effect in driving intraseasonal rainfall 18 o anomalies at our site is supported by an 8 increase in rainfall 18 o that occurred over the course of two weeks in response to a pronounced decrease in regional convective activity dripwater discharge rates underwent a ten fold decrease during the extended dry period but dripwater 18 o values remained constant this study supports the interpretation of stalagmite 18 o records from gunung mulu buda as paleo precipitation records that are sensitive to the location and strength of deep convection in the west pacific warm pool 2007 elsevier b v all rights reserved

multi proxy evidence for human induced deforestation and cultivation from a late holocene stalagmite from middle java indonesia abstract speleothem multi proxy records have proved highly useful in reconstructing past changes in climatic and environmental conditions as well as karst processes and in distinguishing between the numerous potential driving forces that influence these proxies there is lack of such terrestrial proxies from the tropical indo pacific for the first time we present an annual to decadal scale multi proxy record of 377 samples including stable isotopes 18o 13c and trace elements mg ca sr ca from a holocene calcite stalagmite from bribin cave gunung kidul regency middle java indonesia that has grown over the last 4000 years 11 230th dates 18o values average 7 with high frequency variability of up to 1 and hint at relatively stable overall climatic conditions in the tropical indo pacific region during the late holocene the 13c values of stalagmite jb2 are low 13 at the beginning of the record suggesting a c3 dominated rainforest cover strong positive covariation with mg ca and sr ca ratios is a stringent indication of a dominant natural control by prior calcite precipitation and water rock interaction however 13c values increase dramatically by 4 from 1 1 ka to 0 5 ka clear evidence of an anthropogenic influence through deforestation and cultivation

the hydrochemical response of cave drip waters to sub annual and inter annual climate variability wombeyan caves se australia abstract a thorough understanding of cave seepage waters is necessary to interpret geochemical variations in speleothem calcite in terms of changing surface climatic conditions at a particular site here we present the hydrochemistry of ten cave drip waters from a karst system in se australia based on up to 5 5 years of monitoring discharge was continuously measured at six sites and manually at the other sites dripwater samples were analysed for ph electrical conductivity cations and anions at all sites at monthly or more frequent intervals each drip possesses a unique chemistry and not all drip waters responded to antecedent short term hydrological variations for example the hydrochemical behaviour of three adjacent drips at a bedrock depth of 45 m was completely different to that of shallower sites and was apparently un related to surface hydrology throughout the investigation based on modelled calcite precipitation vectors prior calcite precipitation was demonstrated at several sites but can only be linked directly to changes in surface recharge at the shallowest sites at extremely low flow shallow drip waters accessed a high mg sr and ba source thought to be the overlying soil high frequency sample collection allows for the calculation of predicted mg ca calcite and sr ca calcite values highlighting that the sites with the greatest potential to record high resolution palaeohydrological records are those situated at shallow depth longer temporal resolution palaeohydrological records may be recorded at deeper sites but longer term monitoring is required to identify probable time scales inherent system non linearities dissolution of secondary calcite in pore spaces of the aquifer changes in the source of trace elements and the presence of multiple reservoirs confirm the need for the use of multiple speleothems and a multi proxy approach to gain accurate palaeohydrological records from this site

paleointensity applications to timing and extent of eruptive activity 9 10 n east pacific rise placing accurate age constraints on near axis lava flows has become increasingly important given the structural and volcanic complexity of the neovolcanic zone at fast spreading ridges geomagnetic paleointensity of submarine basaltic glass sbg holds promise for placing quantitative age constraints on near axis flows in one of the first extensive tests of paleointensity as a dating tool or temporal marker we present the results of over 550 successful sbg paleointensity estimates from 189 near axis 4 km sites at the east pacific rise 9 10 n paleointensities range from 6 to 53 t and spatially correspond to the pattern expected from known temporal variations in the geomagnetic field samples within and adjacent to the axial summit trough ast have values approximately equal to or slightly higher than the present day samples out to 1 3 km from the ast have values higher than the present day and samples farther off axis have values lower than the present day the on axis samples 500 m from the ast provide a test case for using models of paleofield variation for the past few hundred years as an absolute dating technique results from samples collected near a well documented eruption in 1991 1992 suggest there may be a small negative bias in the paleointensity estimates limiting resolution of the dating technique possible explanations for such a bias include local field anomalies produced by preexisting magnetic terrain anomalously high magnetic unblocking temperatures leading to a small cooling rate bias and or the possibility of a chemical remanence produced by in situ alteration of samples likely to have complicated thermal histories paleointensity remains useful in approximating age differences in young flows and a clear along axis paleointensity contrast near 9 50 n is suggestive of a 150 200 year age difference paleointensity values of off axis samples are generally consistent with rough age interpretations based on side scan data furthermore spatial patterns in the paleointensity suggest extensive off axis flow emplacement may occur infrequently with recurrence intervals of 10 20 kyr results of a stochastic model of lava emplacement show that this can be achieved with a single distribution of flows with flow size linked to time between eruptions