variations in the discharge and organic matter content of stalagmite drip waters in lower cave bristol six drip waters which were actively depositing stalagmites in lower cave bristol were analysed both for discharge and luminescence properties drip discharges were determined for two different years and show a complex response to surface precipitation variations inter annual variability in drip discharge is demonstrated to be significantly higher than intra annual variability and discharge was demonstrated both to increase and decrease non linearly with increased precipitation drip waters demonstrate a correlation between their luminescence intensity and drip discharge with increased luminescence in winter as more organic matter is flushed through the aquifer the strength of the relationship between luminescence intensity and discharge increases with increased discharge the results presented here have implications for the palaeoenvironmental interpretation of annual growth laminae and the growth rates of stalagmite samples 1997 john wiley sons ltd

insolation values for the climate of the last 10 million years new values for the astronomical parameters of the earth s orbit and rotation eccentricity obliquity and precession are proposed for paleoclimatic research related to the late miocene the pliocene and the quaternary they have been obtained from a numerical solution of the lagrangian system of the planetary point masses and from an analytical solution of the poisson equations of the earth moon system the analytical expansion allows the direct determination of the main frequencies with their phase and amplitude numerical and analytical comparisons with the former astronomical solution ber78 are performed so that the accuracy and the interval of time over which the new solution is valid can be estimated the corresponding insolation values have also been computed this analysis leads to the conclusion that the new values are expected to be reliable over the last 5 ma in the time domain and at least over the last 10 ma in the frequency domain

variations in stalagmite luminescence laminae structure at poole s cavern england ad 1910 1996 calibration of a palaeoprecipitation proxy duplicate records of variations in the structure of stalagmite annual luminescence laminae are investi gated for the period ad 1910 to 1996 for poole s cavern buxton central england for the two stalagmites 88 of the years have luminescence laminae that exhibit a near sinusoidal shape with no structural variations however 10 laminae 12 of total exhibit a double band structure these are demonstrated to occur in years with high monthly or daily mean precipitation it is suggested that high intensity 60 mm d 1 and high quantity 250 mm per month of precipitation may flush luminescent organic material onto the stalagmites from either the soil or groundwater zones and generate a double lamina however not all precipitation events generated double laminae high intensity events in summer were ineffective due to a soil moisture deficit and or interception by the woodland canopy high rainfall months 250 mm failed to generate double laminae when preceded by two or more months of greater than 150

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

cyclic rapid warming on centennial scale revealed by a 2650 year stalagmite record of warm season temperature 1 a 2650 year bc665 ad1985 warm season mjja may june july august temperature reconstruction is derived from a correlation between thickness variations in annual layers of a stalagmite from shihua cave beijing china and instrumental meteorological records observations of soil co2 and drip water suggest that the temperature signal is amplified by the soil organism co2 system and recorded by the annual layer series our reconstruction reveals that centennial scale rapid warming occurred repeatedly following multicentenial cooling trends during the last millennia these results correlate with different records from the northern hemisphere indicating that the periodic alternation between cool and warm periods on a sub millennial scale had a sub hemispherical influence

speleothern luminescence intensity and spectral characteristics signal calibration and a record of palaeovegetation change abstract the intensity and spectral characteristics of speleothem luminescence are investigated for signs of any potential palaeoenvironmental signals luminescence in speleothems has been demonstrated to have an organic acid source acids being transported from the overlying soil to the speleothem via the groundwater system luminescence spectral characteristics confirm a humic fulvic acid source of the luminescence but are unable to distinguish between plant acids derived from different vegetation systems spectral characteristics also differ between solid and dissolved speleothem calcite the influence of six factors on luminescence intensity are considered changes in organic acid concentration organic acid structural type depth of the sample below the surface dilution effects through changes in water discharge rate dilution effects through changes in speleothem growth rate and the effects of luminescence quenching due to the presence of metal ions in a holocene stalagmite sample from sutherland a period of low luminescence intensity is observed which is demonstrated to correlate with periods of blanket bog expansion recorded in the regional pollen record this suggestion is supported by a study of 18 recently deposited samples from northwest europe and 5 cave water samples feeding stalagmites in a british cave when a relationship to vegetation is evident with very low luminescence intensity observed from sites overlain by blanket bog deposits this is thought to be due to both low organic acid concentrations in feedwaters and also the low luminescence efficiency of the humic acids from bog sites due to their structural characteristics

u pb isotopic age of the stw 573 hominid from sterkfontein south africa sterkfontein cave south africa has yielded an australopith skeleton stw 573 whose completeness has excited great interest in paleoanthropology stw 573 or little foot was found 25 meters below the surface in the silberberg grotto 238u 206pb measurements on speleothems immediately above and below the fossil remains corrected for initial 234u disequilibrium yield ages of 2 17 0 17 million years ago ma and 2 24 0 07 0 09 ma respectively indicating an age for stw 573 of close to 2 2 ma this age is in contrast to an age of approximately 3 3 ma suggested by magnetochronology and ages of approximately 4 ma based on 10be and 26al but it is compatible with a faunal age range of 4 to 2 ma

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

age and evolution of the grand canyon revealed by u pb dating of water table type speleothems the age and evolution of the grand canyon have been subjects of great interest and debate since its discovery we found that cave mammillaries water table indicator speleothems from nine sites in the grand canyon showed uranium lead dating evidence for an old western grand canyon on the assumption that groundwater table decline rates are equivalent to incision rates samples in the western grand canyon yielded apparent water table decline rates of 55 to 123 meters per million years over the past 17 million years in contrast to eastern grand canyon samples that yielded much faster rates 166 to 411 meters per million years chronology and inferred incision data indicate that the grand canyon evolved via headward erosion from west to east together with late stage 3 7 million years ago accelerated incision in the eastern block

four climate cycles of recurring deep and surface water destabilizations on the iberian margin centennial climate variability over the last ice age exhibits clear bipolar behavior high resolution analyses of marine sediment cores from the iberian margin trace a number of associated changes simultaneously proxies of sea surface temperature and water mass distribution as well as relative biomarker content demonstrate that this typical north south coupling was pervasive for the cold phases of climate during the past 420 000 years cold episodes after relatively warm and largely ice free periods occurred when the predominance of deep water formation changed from northern to southern sources these results reinforce the connection between rapid climate changes at mediterranean latitudes and century to millennial variability in northern and southern polar regions

u pb dating of discordant 0 1 ma old secondary u minerals abstract a modified tera wasserburg u pb concordia plot which takes care of initial disequilibrium of radioactive daughter nuclides has been applied to date discordant torbernite samples from hohenstein northeast bavaria to 137 11ka lower intercept and 66 27ma upper intercept the secondary u pb age is supported by the 230 th 234 u disequilibrium age of 132 4 ka

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

late holocene annual growth in three alpine stalagmites records the influence of solar activity and the north atlantic oscillation on winter climate annual growth rates and the ratio of dark to light colored calcite within single annual laminae in three contemporaneously deposited holocene speleothems from grotta di ernesto an alpine cave in northern italy respond to changes in surface temperature rather than precipitation based on monitoring of present day calcite growth and correlation with instrumental data for surface climatic conditions we interpret a higher ratio of dark to light colored calcite and the simultaneous thinning of annual laminae as indicative of colder than present winters such dark and thin laminae occur in those parts of the three stalagmites deposited from ad 1650 to 1713 and from ad 1798 to 1840 as reconstructed through lamina counting these periods correspond to the well known maunder and dalton minima of solar activity an 11 yr cyclicity in growth rate coupled with reduced calcite deposition during the historic minima of solar activity is indicative of a solar influence on lamina thickness spectral analysis of the lamina thickness data also suggests that the north atlantic oscillation variability influenced winter temperatures based on the present day controls on cave calcite formation we infer that high frequency changes in solar activity modulated the seasonal duration of soil co2 production

speleothem palynology an undervalued tool in quaternary studies palynological analysis of cave sediments in particular the analysis of pollen from speleothems is not a widely adopted approach to palaeoenvironmental studies in the british isles this disregard of speleopalynology may be due to the lack of understanding of the cave pollen taphonomy and uncertainty and suspicion as to what cave pollen spectra actually represent however a number of studies of pollen from caves have been carried out particularly in belgium france and spain which have demonstrated speleothem pollen spectra to be representative of contemporary vegetation above the cave with pollen generally well preserved speleothems have the distinct advantage over other pollen sources that they can be dated by high precision tims u th dating up to an order of magnitude further back in time than 14c dating of organic sediments would allow this potentially allows previously unconstrained middle pleistocene palynological records to be precisely and accurately dated thus providing a geochronologically controlled terrestrial record of palaeoenvironmental change this paper presents a timely review of speleothem palynology aiming to eliminate biases and misconceptions and illustrate the enormous potential this unique source of palaeoenvironmental data holds particularly in providing accurately dated pollen records from previously understudied environments and time periods

speleothems from the earliest quaternary snapshots of paleoclimate and landscape evolution at the northern rim of the alps abstract ancient cave systems in the northern calcareous alps today located well above the timberline at altitudes of 2400 2500 m host u rich speleothems that preserved growth layers on the microscopic scale of presumably annual origin two flowstone samples were dated to 2 019 0 037 0 069 ma and 1 730 0 032 0 068 ma respectively using u pb isochron techniques these ages are corroborated by the late pliocene to early pleistocene pollen spectrum extracted from one of the samples we use a multiproxy approach and exploit laminated speleothem sequences to tie high resolution stable isotope data to a floating lamina counted chronology o isotope values of growth intervals when calcite deposition was close to isotopic equilibrium are low compared to modern and holocene speleothems from other alpine caves and are inconsistent with the current altitudinal setting of the caves a vegetated but geomorphologically stable alpine catchment i e 2000 m asl no peri glacial processes combined with a deep seated cave the thickness of the vadose zone might have exceeded 1000 m is required in order to reconcile the isotopic data with the pollen record and the petrographic evidence furthermore the data can be used to constrain the rate for quaternary rock uplift to 0 8 mm annum for this frontal part of the european alps collectively the data suggest that these speleothems formed both during interglacials mis 59 or 61 and interglacial glacial transitions mis 75 74 or 77 76 but the seasonal precipitation pattern was arguably markedly different from today s provided that the highly regular microscopic laminae are indeed annual lamina counts suggest a minimum length of ca 6 ka for interglacials during the earliest pleistocene

post earthquake denudation and its impacts on ancient civilizations in the chengdu longmenshan region china this study characterizes significant changes in denudation and disasters in mountainous areas induced in the humid chengdu longmenshan region by the wenchuan earthquake in 2008 a study focusing on the longxi baisha river basin was conducted to investigate the amount of denudation triggered by specific flash flood and debris flow events in 2009 2014 the following results were obtained through a comparison of pre seismic regional denudation rates and denudation characteristics of other seismically active mountain regions 1 regional denudation processes occurred in a wave like process of initial increase then decline with a peak exhibiting a hyperbolic attenuation trend this trend indicates that the denudation rate in the chengdu longmenshan region is expected to return to the pre seismic rate of 0 3 mm a 1 after 81 years in 22 years after the earthquake year 2030 debris flow disasters are expected to be rare 2 disasters increased significantly in the chengdu longmenshan region after the wenchuan earthquake with an average of 29 5 people missing or dead per year 22 times greater than the pre earthquake rate and average economic losses of 192 million yuan per year 1 6 times greater than the pre earthquake rate 3 the denudation process was jointly controlled by the quantities of loose solid material and precipitation after the wenchuan earthquake the amount of loose solid material influenced the extent of denudation while vegetation coverage rates and soil consolidation determined the overall denudation trend in the region and changes in precipitation led to denudation fluctuations 4 the results can be used to analyze the relationship between the potential flash flood debris flow disasters after earthquakes in the ancient shu kingdom and changes in historical social settlements the results can also be used to predict denudation processes and disaster risks from earthquakes in humid mountainous regions around the world such as the southern slope of the himalayas japan and the taiwan mountains c 2018 elsevier b v all rights reserved

final closure of panama and the onset of northern hemisphere glaciation abstract the greenland ice sheet is accepted as a key factor controlling the quaternary glacial scenario however the origin and mechanisms of major arctic glaciation starting at 3 15 ma and culminating at 2 74 ma are still controversial for this phase of intense cooling ravelo et al 1 a c ravelo d h andreasen m lyle a o lyle m w wara regional climate shifts caused by gradual global cooling in the pliocene epoch nature 429 2004 263 267 proposed a complex gradual forcing mechanism in contrast our new submillennial scale paleoceanographic records from the pliocene north atlantic suggest a far more precise timing and forcing for the initiation of northern hemisphere glaciation nhg since it was linked to a 2 3 c surface water warming during warm stages from 2 95 to 2 82 ma these records support previous models g h haug r tiedemann effect of the formation of the isthmus of panama on atlantic ocean thermohaline circulation nature 393 1998 673 676 2 claiming that the final closure of the panama isthmus 3 0 2 5 ma j groeneveld s steph r tiedemann d nurnberg d garbe schonberg the final closure of the central american seaway geology in prep 3 induced an increased poleward salt and heat transport associated strengthening of north atlantic thermohaline circulation and in turn an intensified moisture supply to northern high latitudes resulted in the build up of nhg finally culminating in the great irreversible climate crash at marine isotope stage g6 2 74 ma in summary there was a two step threshold mechanism that marked the onset of nhg with glacial to interglacial cycles quasi persistent until today

warm period growth of travertine during the last interglaciation in southern germany abstract late quaternary travertine at two sites near stuttgart formed entirely during interglacial periods the travertine contains structures from growth induced by bacteria and such structures have been dated by 230th u mass spectrometry the resulting ages from both sites imply growth episodes of short duration with growth rates up to 5 mm yr 1 at 99 800 1300 yr b p 2 n 8 and 105 900 1300 yr b p 2 n 7 these episodes were likely part of marine isotope stage mis 5 3 deposition of silt interrupted travertine growth at one of the sites 105 000 yr b p likely correlatives of this silt are the st germain i b stade recorded in the grand pile peat bog and a cold episode 1000 yr long recorded by 18o values in the grip ice core travertine also formed during stage 5 5 115 000 yr and during the early holocene we found no evidence for travertine accumulation in stages 2 3 4 and 5 1 at both sites the sr u ratio and the initial 234u 238u activity ratio resemble those of modern spring water however the sites differ in the chemical composition of spring water and in stratigraphic sequence of travertine accumulation

high resolution record of northern hemisphere climate extending into the last interglacial period high resolution record of northern hemisphere climate extending into the last interglacial period

paleoclimate implications of mass spectrometric dating of a british flowstone the timing of growth phases in a cave flowstone from yorkshire england has been precisely dated by thermal ionization mass spectrometric 238u 234u 230th dating six growth periods of both short duration and fast growth rate are separated by nondepositional hiatuses the ages of these phases were determined to be 128 8 2 7 103 1 1 8 84 7 1 2 57 9 1 5 49 6 1 3 and 36 9 0 8 ka there is a remarkably good correlation between the periods of active speleothem growth and the timing of solar insolation maxima derived from orbital parameters which has not previously been reported speleothem growth theory and evidence from other terrestrial paleoclimate records suggest that episodic rapid growth phases at the insolation maxima are most likely to be caused by changes in either precipitation intensity or volume which caused switching in the routing of water flow in the unsaturated zone above the cave such a result provides new evidence of the importance of variations in solar insolation for terrestrial paleoclimate and offers the potential for derivation of a paleowetness index from speleothem growth

seasonality intensification and long term winter cooling as a part of the late pliocene climate development abstract a mutual climatic range method is applied to the mediterranean marine pollen record of semaforo vrica section calabria italy covering the period from 2 46 ma to 2 11 ma the method yields detailed information on summer annual and winter temperatures and on precipitation during the nine obliquity and precession controlled glacial periods marine isotope stages 96 to 80 and eight interglacial periods marine isotope stages 95 to 81 characterising this time interval the reconstruction reveals higher temperatures of at least 2 8 c in mean annual and 2 2 c in winter temperatures and 500 mm in precipitation during the interglacials as compared to the present day climate in the study area during the glacials temperatures are generally lower as compared to the present day climate in the region but precipitation is equivalent along the consecutive interglacials a trend toward a reduction in annual and winter temperatures by more than 2 3 c and toward a higher seasonality is observed along the consecutive glacials a trend toward a strong reduction in all temperature parameters of at least 1 6 c is reconstructed climatic amplitudes of interglacial glacial transitions increase from the older to the younger cycles for summer and annual temperatures the cross spectral analyses suggest obliquity related warm humid cold dry interglacial glacial cycles which are superimposed by precession related warm dry cold humid cycles a time displacement in the development of temperatures and precipitation is indicated for the obliquity band by temperatures generally leading precipitation change at 4 kyr and on the precession band of 9 6 kyr in maximum

factors controlling carbonate dissolution rates quantified in a field test in the austrian alps carbonate dissolution rates were investigated by measuring the mass difference of carbonate tablets exposed to natural dissolution for 1 year 70 tablets were distributed over 13 test sites on the north slope of the hochschwab massif in the austrian alps the influences of altitude subsoil vs sub aerial exposure vegetation karst morphology soil humidity sample lithology and sample surface morphology were investigated the observed dissolution rates varied between 13 and 40 m a for subcutaneous samples and about 11 m a for sub aerial exposure outstandingly high rates of 48 m a were observed in a doline and nearly zero rates were measured at a site influenced by seeping spring water a mass balance using high resolution hydrological data was calculated for the klaffer spring which has an average outflow of 4 8 m3 s it indicated a loss of 21 106 kg of carbonate rock per year which gives an average dissolution rate of 95 m a for the catchment area of 83 km2 the dissolution rates of 10 m a from the sub aerially exposed samples are comparable to values from limestone pedestals which were protected from dissolution by glacial erratics for the past 15 ka

annual growth banding in a cave stalagmite the presence of microscopic luminescence banding in cave calcite deposits speleothems has recently been reported1 3 the luminescence seems to be caused by excitation of humic and fulvic acids derived from the overlying soil and subsequently incorporated into the calcite3 4 we have tested whether such luminescence corresponds to annual growth layers using high precision thermal ionization mass spectrometric 238u 234u 230 th ages from banded sections of a holocene stalagmite we report here that the timespans yielded by counting bands on the assumption that they are annual agree within error limits with those obtained by our uranium thorium dating this demonstration that the banding is annual should make banded speleothems valuable resources for providing high resolution records of past climate in which precipitation can be estimated from growth rates5 6 and temperatures from stable isotope measurements7 and solar terrestrial correlations as the luminescence intensity can be related to the solar sunspot cycle1 3

roles of mesoscale eddies in the kuroshio paths a high resolution ocean general circulation model is developed to simulate connections between the kuroshio path variations and mesoscale eddy activities as realistically as possible the climatological mean of the modeled kuroshio takes a nearshore nonlarge meander path it is found that the model is capable of simulating two types of nonlarge meander state and a possible version of the large meander state the offshore nonlarge meander is generated through interaction between the kuroshio and an anticyclonic eddy the large meander occurs just after significant intensification of the anticyclonic kuroshio recirculation successive intrusion of anticyclonic eddies from the upstream region is responsible for this process those anticyclonic eddies are advected by the kuroshio from the region northeast of luzon island and increase the upstream kuroshio volume transport on an interannual time scale the cyclonic eddies propagating from the kuroshio extension region on the other hand weaken the kuroshio meander after the merger the kuroshio path variations south of japan thus seem to be closely related to eddy activities in the subtropical gyre system

migration of sharks into freshwater systems during the miocene and implications for alpine paleoelevation trace element and isotopic compositions of fossilized shark teeth sampled from miocene marine sediments of the north alpine molasse basin the vienna basin and the pannonian basin generally show evidence of formation in a marine environment under conditions geochemically equivalent to the open ocean in contrast two of eight shark teeth from the swiss upper marine molasse locality of la moliere have extremely low 18o values 10 3 and 11 3 and low 87sr 86sr ratios 0 707840 and 0 707812 compared to other teeth from this locality 21 1 22 4 and 0 708421 0 708630 the rare earth element ree abundances and patterns from la moliere not only differ between dentine and enameloid of the same tooth but also between different teeth supporting variable conditions of diagenesis at this site however the ree patterns of enameloid from the exotic teeth analyzed for o and sr isotopic compositions are similar to those of teeth that have o and sr isotopic compositions typical of a marine setting at this site collectively this suggests that the two exotic teeth were formed while the sharks frequented a freshwater environment with very low 18o content and sr isotopic composition controlled by mesozoic calcareous rocks this is consistent with a paleogeography of high elevation 2300 m miocene alps adjacent to a marginal sea

comparison of the luminescence properties of waters depositing flowstone and stalagmites at lower cave bristol discharge and luminescence properties of waters feeding a flowstone in lower cave bristol were measured at both three weekly and 30 minute sampling intervals within rainfall events over the period april 1994 april 1995 and july december 1995 respectively results are compared with the discharge and luminescence of lower 0 01 ml s 1 feeding flowstones when 30 minute sampling results are considered dilution and hysteresis effects can be observed in the discharge luminescence relationship both on an intra event basis and over the winter as a whole exhaustion of organic matter within the karst groundwater system over the hydrological year may also be important a very rapid flux of luminescent organic matter in early autumn generates a non linear order of magnitude change in water luminescence intensity flowstone water luminescence properties can be interpreted as having i higher concentrations of luminescent organic matter compared with stalagmites from luminescence intensity data 2 a greater proportion of humic acid in relation to fulvic acid from luminescence wavelength data 3 a more rapid response to surface rainfall events and 4 a consequently greater proportion of non linear responses to surface rainfall variations these results are considered in terms of the utility of the analysis of luminescence variations in solid samples of stalagmites and flowstones in aiding the reconstruction of past rainfall variations and it is suggested that stalagmites are more useful than flowstones

quaternary erosion induced isostatic rebound in the western alps the high elevation and deep incision of the alps have traditionally been used as an argument for recent tectonic activity that has elevated the belt and increased erosion rates normal faulting and horizontal extension however dominate current tectonic activity and isostatic compensation of thinning crust should lead not to increased but to decreased mean elevations here we test the idea that enhanced quaternary erosion of the alps and isostatic compensation of the mass removed can account for the distribution of present day geodetically measured rates of vertical movement in the western alps using geophysical relief and kuhlemann s estimated average erosion rate for the alps we quantify the spatial distribution of erosion and the volume of eroded rock respectively from these we obtain a map of rock eroded within a given time span the calculated isostatic response of the alpine lithosphere to erosional unloading for a variety of values of the flexural rigidity of the alpine lithosphere reaches a maximum of 500 m since 1 ma in the inner swiss alps and vertical movement extends across the entire belt including peri alpine basins assuming a steady erosion rate since 1 ma this rebound accounts for half of the measured vertical motion of 1 1 mm yr in the southern valais thus a significant fraction 50 of the present day vertical movement results from the isostatic response to enhanced erosion during plio quaternary time

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

the younger dryas and holocene climate record of a stalagmite from holloch cave bavarian alps germany stable isotope analyses and seven u th dates of a stalagmite from the alpine holloch cave germany have yielded a palaeoclimate record for the past 14 300 yr the 18o record is positively correlated with relative temperature variations the late glacial part of this record including the younger dryas exhibits a striking correlation with records from ice cores lake sediments and marine sediments in addition this record suggests relatively high temperatures and distinct temperature fluctuations from 9000 4200 yr bp if compared with the 4200 0 yr bp period matching the regional soil formation erosion and timberline patterns the 13c record appears to have been controlled mainly by soil formation 14 300 9000 yr bp and by humidity variations 9000 0 yr bp copyright 2004 john wiley sons ltd

surface uplift uplift of rocks and exhumation of rocks uplift of the surface of mountain belts requires forces that are comparable in magnitude to those associated with plate motion and therefore determination of rates of surface uplift could provide important information on the dynamics of mountain ranges rates of uplift of the surfaces of mountain ranges have not however been quantified sufficiently well that they provide useful constraints on those processes many reports off surface uplift in mountain ranges are based on mistaking exhumation of rocks or uplift of rocks for surface uplift and provide no information whatsoever on the rates of surface uplift

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

late pliocene northern hemisphere glaciations the continental and marine responses in the central mediterranean abstract detailed pollen analyses and oxygen isotope records of three foraminiferal species globigerina bulloides uvigerina peregrina and cibicides pachyderma from the semaforo and vrica composite sections crotone southern italy have been compared to the global climatic changes depicted by late pliocene early pleistocene foraminiferal 18o records of site 607 in the north atlantic and hole 653a in the tyrrhenian basin west mediterranean major overturns in the mid altitude vegetation are shown near isotopic stages 82 60 58 and 50 at about 2 03 ma 1 6 ma and 1 37 ma according to the raymo et al 1989 and ruddiman et al 1989 timescales at the same dates glacial 18o maxima either became higher or display step increases in the western mediterranean or in the open ocean as well this suggests that size increases of northern hemisphere ice sheets were the driving factor for regional or local marine and continental environmental changes within the mediterranean basin near isotopic stages 62 60 close to the conventional plio pleistocene boundary the climatic conditions severed enough within the mediterranean basin to modify the continental environment as depicted by a sudden increase of artemisia percentages while the first significant southward migration of the north polar front may have been recorded by an influx of left coiling neogloboquadrina pachyderma in the central mediterranean it also appears that boreal guests entered the mediterranean during phases of 18o enrichment of foraminiferal calcite there does not seem to be any discrepancy between the climatic concept of the pliocene pleistocene boundary and its chronostratigraphic definition

organic acid fluorescence applications to speleothem palaeoenvironmental reconstruction abstract recent advances in fluorescence spectrophotometry permit the non destructive analysis of speleothems secondary carbonate cave deposits with a view to palaeoenvironmental reconstruction the fluorescence of speleothems is derived from organic acids that have been carried by groundwater from the overlying soil and coprecipitated with the speleothem calcite organic acids are formed as one of the many products of humification and their chemical structures are such that they are particularly suitable for analysis by fluorescence spectrophotometry numerous studies have been carried out that have demonstrated the structure and hence the fluorescence properties of organic acids to be influenced by many factors including extraction method concentration source ph metal and inorganic ion complexing and most importantly in the case of speleothems soil type and climate and vegetation change on the basis of this recent investigations carried out on contemporary historical and quaternary samples have shown it to be possible to obtain palaeoenvironmental information from the fluorescence properties of organic acids in speleothems

late pliocene millennial scale climate variability in the northern north atlantic prior to and after the onset of northern hemisphere glaciation 1 sediments recovered at ocean drilling program site 984 on the reykjanes ridge provided multicentennial scale records of late pliocene climate change over the onset of northern hemisphere glaciation nhg 2 95 2 82 ma short term climate variations prior to and after the onset of continent wide glaciation were compared to test the hypothesis of whether dansgaard oeschger do cycles may have been triggered by continental ice breakouts during two selected interglacial stages prior to and after nhg g15 and g1 climate variability resembled that found in the holocene and the mid pliocene warm period in contrast do like periodicities of 1470 2900 and 4400 years indeed only occurred in glacial stages after the onset of nhg g14 g6 and 104 but not in stage g20 prior to the onset these results suggest a causal link between do cycles and the late pliocene onset of major nhg and ice breakouts in the north atlantic

modelling stalagmite growth and δ13c as a function of drip interval and temperature abstract growth and stable isotope composition of stalagmites are affected by climate changes to understand the underlying mechanisms we developed a time dependent multi box model that describes stalagmite growth and stable isotope fractionation of carbon under disequilibrium conditions the model takes variations of the drip interval temperature and the amount of mixing between the impinging drops and the solution on top of the stalagmite into account which allows to quantify the influence of these parameters to calculate the variations of 13c the multi box model was calibrated by comparison with an existing growth model the results show that drip interval temperature and the mixing coefficient do have a significant influence on 13c however considering the higher natural variability of the drip interval this parameter might have the largest influence