varves of the dead sea sedimentary record abstract the sedimentary record of the dead sea provides an exceptional high resolution archive of past climate changes in the drought sensitive eastern mediterranean levant a key region for the development of humankind at the boundary of global climate belts moreover it is the only deep hypersaline lake known to have deposited long sequences of finely laminated annually deposited sediments i e varves of varied compositions including aragonite gypsum halite and clastic sediments vast efforts have been made over the years to decipher the environmental information stored in these evaporitic clastic sequences spanning from the pleistocene lake amora to the holocene dead sea a general characterisation of sediment facies has been derived from exposed sediment sections as well as from shallow and deep water sediment cores during high lake stands and episodes of positive water budget mostly during glacial times alternating aragonite and detritus laminae aad facies were accumulated whereas during low lake stands and droughts prevailing during interglacials laminated detritus ld facies and laminated halite lh facies dominate the sequence in this paper we i review the three types of laminated sediments of the dead sea sedimentary record aad ld and lh facies ii discuss their modes of formation deposition and accumulation and their interpretation as varves and iii illustrate how dead sea varves are utilized for palaeoclimate reconstructions and for establishing floating chronologies

survey and explorations of caves in southeastern ethiopia middle stone age and later stone age archaeology and holocene rock art abstract the horn of africa provides the setting for the evolution of early modern humans and their dispersal out of africa as well as for the entry many thousands of years later of pastoralists who brought near eastern and later south asian livestock into africa however significant gaps remain in our understanding of the late upper pleistocene archaeological record of the horn of africa mainly due to the paucity of well stratified sites from the period the discovery in southeastern ethiopia of a number of caves with rich upper pleistocene and holocene archaeological deposits many of which also had rock art depicting domestic animals offers an unprecedented opportunity for exploring the later prehistory of the region in 2007 2008 our survey documented twenty one cave sites and shelters with evidence of cultural deposits including middle stone age msa and later stone age lsa stone artifacts faunal remains and rock art active and fossil speleothems important for paleoclimatic reconstructions and chronology were found from two other caves in eastern and western harerghe test excavations were conducted at three sites with abundant archaeological material documented from stratified deposits at two of these sites gilbo tate and goda buticha the latter is a subject of another paper in this volume rock art was recorded at eighteen sites three of which in western harerghe had not previously been documented at many of the sites much of the art is faded and in a vulnerable state and continued efforts to document and conserve this art are urgently needed

a speleothem based mid holocene precipitation reconstruction for west central florida the mid holocene was the warmest segment of the current interglacial and possessed a weak latitudinal temperature gradient which impacted climate teleconnections and thus precipitation variability

the circulation of the dead sea brine in the regional aquifer abstract ca chloride brines have circulated between the lakes and the adjacent aquifers throughout the history of the dead sea lacustrine hydrology system the ein qedem eq hydrothermal saline springs system discharging at the western shores of the modern dead sea is the modern manifestation of this essential and continuous process the eq springs comprise the most significant source of ca chloride brine that currently discharges into the lake the chemical composition of eq brine has remained virtually uniform during the past ca 40 yr indicating that the brine represents a large groundwater reservoir the eq brine evolved from ancient ca chloride brine that occupied the tectonic depression of the dead sea basin during the quaternary during this period the composition of lake s brine was affected by mixing with freshwater and formation of primary minerals based on chronological and geochemical data we argue that the eq brine comprises the epilimnetic solution of last glacial lake lisan that penetrated and circulated through the adjacent judea group aquifer 14c and 81kr dating indicates recharge ages spanning the time interval of 40 20 ka coinciding with the period when the lake reached its highest stand of 200 30 m below msl at 31 17 4 ka and maintained a stable layered stratified configuration for a period of several ten thousand years the presented evidence suggests that the circulation of the ca chloride brine involves penetration into the aquifer during high stands eq brine recharge and its discharge back into the lake during the modern low stands 400 to 430 m below msl accordingly the mechanism of brine circulation between the lake and the marginal aquifers is related to the long term hydro climate history of the dead sea basin and its vicinity

rainfall and cave water isotopic relationships in two south france sites this article presents isotopic measurements 18o and d of precipitation and cave drip water from two sites in southern france in order to investigate the link between rainfall and seepage water and to characterize regional rainfall isotopic variability these data which are among the longest series in france come from two rainfall stations in south west france le mas 1996 2012 and villars 1998 2012 typically under atlantic influence and from one station in the south east orgnac 2000 2012 under both mediterranean and atlantic influence rainfall isotopic composition is compared to drip water collected under stalactites from the same sites villars cave four drip stations 1999 2012 in the south west and chauvet cave two drip stations 2000 2012 in the south east near orgnac the study of these isotopic data sets allows the following conclusions to be drawn about the rainfall drip water relationships and about rainfall variability 1 the cave drip water isotopic composition does not show any significant changes since the beginning of measurements in order to explain its isotopic signature it is necessary to integrate weighted rainfall 18o of all months during several years which demonstrates that even at shallow depths 10 50 m cave drip water is a mixture of rain water integrated over relatively long periods which give an apparent time residence from several months to up to several years these results have important consequences on the interpretation of proxies like speleothem fluid inclusions and tree ring cellulose isotopic composition which are used for paleoclimatic studies 2 in the villars cave where drip stations at two different depths were studied lower 18o values were observed in the lower galleries which might be due to winter season overflows during infiltration and or to older rain water with a different isotopic composition that reaches the lower galleries after years 3 local precipitation is characterized by local meteoric water lines lmwl with 18o d slopes close to 7 in both areas and correlations between air temperature and precipitation 18o are low at both monthly and annual scales even with temperature weighted by the amount of precipitation 4 the mesoscale climate model remoiso equipped with a water isotope module allows the direct comparison of modeled and observed long term water isotope records the model slightly overestimates rainfall 18o at the respective sampling stations however it simulates very well not only the seasonal rainfall isotopic signal but also some intra seasonal patterns such as a typical double peak 18o pattern in winter time

abrupt or gradual change point analysis of the late pleistocene holocene climate record from chew bahir southern ethiopia we used a change point analysis on a late pleistocene holocene lake sediment record from the chew bahir basin in the southern ethiopian rift to determine the amplitude and duration of past climate transitions the most dramatic changes occurred over 240 yr from similar to 15 700 to 15 460 yr during the onset of the african humid period ahp and over 990 yr from similar to 4875 to 3885 yr during its protracted termination the ahp was interrupted by a distinct dry period coinciding with the high latitude younger dryas stadial which had an abrupt onset less than similar to 100 yr at similar to 13 260 yr and lasted until similar to 11 730 yr wet dry wet transitions prior to the ahp may reflect the high latitude dansgaard oeschger cycles as indicated by cross correlation of the potassium record with the northgrip ice core record between similar to 45 20 ka these findings may contribute to the debates regarding the amplitude and duration and mechanisms of past climate transitions and their possible influence on the development of early modern human cultures

comparison of varve and 14c chronologies from steel lake minnesota usa annually laminated sediments varves offer an effective means of acquiring high quality palaeoenvironmental records however the strength of a varve chronology can be compromised by a number of factors such as missing varves ambiguous laminations and human counting error we assess the quality of a varve chronology for the last three millennia from steel lake minnesota through comparisons with nine ams 14c dates on terrestrial plant macrofossils from the same core these comparisons revealed an overall 8 4 discrepancy primarily because of missing uncountable varves within two stratigraphic intervals characterized by low carbonate concentrations and obscure laminations application of appropriate correction factors to these two intervals results in excellent agreement between the varve and 14c chronologies these results together with other varve studies demonstrate that an independent age determination method such as 14c dating is usually necessary to verify and potentially correct varve chr

sedimentary and structural controls on seismogenic slumping within mass transport deposits from the dead sea basin abstract comparatively little work has been undertaken on how sedimentary environments and facies changes can influence detailed structural development in slump sheets associated with mass transport deposits mtds the nature of downslope deformation at the leading edge of mtds is currently debated in terms of frontally emergent frontally confined and open toed models an opportunity to study and address these issues occurs within the dead sea basin where six individual slump sheets s1 s6 form mtds in the late pleistocene lisan formation all six slumps which are separated from one another by undeformed beds are traced towards the ne for up to 1 km and each shows a change in sedimentary facies from detrital rich in the sw to more aragonite rich in the ne the detrital rich facies is sourced predominantly from the rift margin 1 5 km further sw while the aragonite rich facies represents evaporitic precipitation in the hyper saline lake lisan the stacked system of mtds translates downslope towards the ne and follows a pre determined sequence controlled by the sedimentary facies each individual slump roots downwards into underlying detrital rich layers and displays a greater detrital content towards the sw which is marked by increasing folding while increasing aragonite content towards the ne is associated with more discrete thrusts the mtds thin downslope towards the ne until they pass laterally into undeformed beds at the toe the amount of contraction also reduces downslope from a maximum of 50 to

decadal cyclicity of regional mid holocene precipitation evidence from dominican coral proxies 1 the stable carbon 13c and oxygen 18o isotopic compositions of four holocene specimens of montastraea sp and siderastrea sp coral skeletons from the dominican republic were analyzed to examine decadal scale fluctuations in regional precipitation the specimens range in length from 47 to 197 years individually and range in age from 7 2 to 5 2 kyr oscillations in the 13c and 18o of coral skeletons from the holocene enriquillo valley occur with a seemingly consistent frequency of 15 20 years for one coral 6 ka this decadal to multidecadal mode of variability is statistically significant the decadal to multidecadal mode of stable isotopic variability may represent cyclic fluctuations in mid holocene migration of the intertropical convergence zone itcz or in the hydrogeology of the region as governed by fluctuations in the passage of tropical storms and hurricanes regional temperature is believed to act as only a secondary control on the 18o values of these corals however itcz migration and or oscillations in storm frequency at this site may ultimately reflect decadal scale patterns in greater tropical north atlantic sea surface temperatures the length and resolution of climate variability represented in this study indicate a persistent decadal to multidecadal mode of atlantic climate fluctuation throughout the mid holocene that is indistinguishable from observed historical climate

isotopic characterization of cave environments at varying altitudes on the eastern adriatic coast croatia implications for future speleothem based studies abstract an important step in the implementation of paleoclimate reconstructions from speleothems cave carbonate deposits is to evaluate the sensitivity of the host cave environment to regional climate accordingly we studied three caves at different altitudes 74 m 570 m and 1250 m a s l along a transect from the dalmatian islands to velebit mountain peaks in coastal croatia to characterize their environments in terms of each cave s suitability to host speleothems that would be capable of yielding robust paleoclimate reconstructions we conducted cave microclimate 2 years and dripwater 1 year monitoring and analysed the isotopic composition of precipitation cave dripwater and modern spelean calcite as for the water isotopic imprints the isotopic values of meteoric waters reaching the two lower altitude caves in spite of an altitude difference of 500 m lie on local meteoric water lines lmwls of similar slope and intercept 2 h 6 61 18 o 4 92 and 2 h 6 69 18 o 6 86 their slopes lower than that of gmwl indicate enhanced evaporation during the warm season as expected the lmwl of the highest cave region 2 h 7 83 18 o 14 45 resembles the slope of the gmwl but the values of deuterium excess obtained for all three caves between 15 2 and 16 6 match that of western mediterranean sourced waters 15 monthly d excess values suggest atlantic sourced air masses can reach the sites throughout the year but never dominate the rainfall composition the altitude effect was noted both in precipitation and in dripwater isotopic composition but with notably different 18 o 100 m gradients 0 33 and 0 11 respectively stable isotope variations of the dripwaters in all caves were attenuated in relation to the rainwater even those of the drip sites with fracture flow behaviour based on stable cave microclimate conditions relatively steady discharges and modern calcite apparently precipitated at or close to isotopic equilibrium with dripwater the two caves at lower altitudes show the greatest potential for future paleoclimate studies the cave at the highest altitude experiences large cave air temperature amplitudes 5 3 c and pronounced ventilation making the isotopic signal susceptible to kinetic fractionation which might preclude quantification of environmental changes but on the other hand it accentuates isotopic events making them easier to identify

catastrophic arid episodes in the eastern mediterranean linked with the north atlantic heinrich events the response of continental climate to the well documented climate oscillations during the last glacial period has been a subject of intense interest yet much less is known about the influence on regional continental climates than in the marine or polar realms of earth the detailed lake level history of the closed lake lisan paleo dead sea in the middle east has been reconstructed from shoreline indications and high resolution u th and 1 4 c chronologies thus providing data on the response of the lake s catchment area to the climate changes during the corresponding period we present a correlation between the newly developed lake lisan level curve for the past 55 k y and the north atlantic heinrich events the correlation indicates a closely connected climate response between these north atlantic events and the hydrologic conditions that prevailed in the eastern mediterranean our findings show that although the generally cooler conditions that prevailed during the last glaciation favored high levels of the lake catastrophic events in the north atlantic which are associated with maximum cooling have been responsible for droughts in the eastern mediterranean we infer that cold water input to the mediterranean originating in the collapse of the north atlantic deep water circulation caused the reduction of evaporation and less precipitation in the eastern mediterranean

reply to comment on ben dor y et al varves of the dead sea sedimentary record quaternary science reviews 215 2019 173 184 abstract in the comment on varves of the dead sea sedimentary record quaternary science reviews 215 ben dor et al 2019 173 184 by r bookman two recently published papers are suggested to prove that the interpretation of the laminated sedimentary sequence of the dead sea deposited mostly during mis2 and holocene pluvials as annual deposits i e varves is wrong in the following response we delineate several lines of evidence which coalesce to demonstrate that based on the vast majority of evidence including some of the evidence provided in the comment itself the interpretation of these sediments as varves is the more likely scientific conclusion we further discuss the evidence brought up in the comment and its irrelevance and lack of robustness for addressing the question under discussion

hypersaline brine diagenesis and evolution in the dead sea lake lisan system israel abstract water soluble salts were extracted from 57 aragonite and detrital laminae sampled from the pleistocene lake lisan sediments the solutions and solids were analysed for ca mg na k sr cl so 4 and bicarbonate average na cl mg ca sr ca mg cl ca cl sr cl k cl k na and k mg ratios calculated for seven stratigraphie elevations in the lisan column indicate that the dead sea rift sediment brine system has remained practically closed for 70000 years the soluble salts reflect both the hydrologie evolution of the lake as well as diagenetic processes mg ca ratios systematically decrease in younger sediments and this decline is accompanied by a 1 5 4 fold sr enrichment in aragonite solubles relative to salts extracted from detrital laminae the major process responsible for these observations is dolomitization of sr rich aragonite by interstitial brine diagenesis was triggered by slow desiccation of the lake s sediments after the lisan waters started to recede due to a change in climate very sharp chemical gradients which developed in the sediments after deposition have been preserved because further diagenesis was quenched by the advancing dry out h 2 o loss by evaporation induced difrusional migration of na and cl from aragonite laminae into adjacent detrital layers this lowered the na cl ratio in the aragonite and raised it in the detritus relative to the initial dead sea na cl ratio of 0 26 the early lisan brine was similar in its chemical composition and total salinity to that of the present dead sea

fold and thrust systems in mass transport deposits abstract improvements in seismic reflection data from gravity driven fold and thrust systems developed in offshore mass transport deposits mtds reveal a number of significant features relating to displacement along thrusts however the data are still limited by the resolution of the seismic method and are unable to provide detail of local fold and thrust processes investigation of exceptional gravity driven contractional structures forming part of mtds in lacustrine deposits of the dead sea basin enables us to present the first detailed outcrop analysis of fold and thrust systems cutting unlithified soft sediments we employ a range of established geometric techniques to our case study including dip isogons fault propagation fold charts and displacement distance diagrams previously developed for investigation of thrusts and folds in lithified rocks fault propagation folds in unlithified sediments display tighter interlimb angles compared to models developed for lithified sequences values of stretch which compares the relative thickness of equivalent hangingwall and footwall sequences measured along the fault plane may be as low as only 0 3 which is significantly less than the minimum 0 5 values reported from thrusts cutting lithified rocks and reflects the extreme variation in stratigraphic thickness around thrust related folds we suggest that the simple shear component of deformation in unlithified sediments may modify the forelimb thickness and interlimb angles to a greater extent than in lithified rocks the average spacing of thrust ramps and the thickness of the thrust sequence display an approximate 5 1 ratio across a range of scales in mtds in general thicker hangingwall and footwall sequences occur with larger thrust displacements although displacement patterns on thrusts cutting unlithified yet cohesive sediments are more variable than those in lithified rocks line length restoration of thrust systems in mtds reveals 42 shortening which reduces to 35 in overlying beds a 23 reduction in shortening by folding and thrusting along individual thrusts suggests that heterogeneous lateral compaction may increase by 10 towards the sediment surface thrust systems cutting unlithified sediments display distinct steps in cumulative displacement distance plots representing increased rates of slip along the floor thrust while displacement distance plots along individual thrusts also reveal horizontal steps relating to lithological variation competent units cut by thrust ramps may display the greatest displacement which then progressively reduces both upward and sometimes downward along the ramp this relationship demonstrates that ramps do not necessarily propagate upwards from the underlying flat as in some traditional models but rather initiate by offset of competent horizons in the hangingwall of the detachment critical taper angles in mtds may be an order of magnitude less than in accretionary complexes or lithified rocks overall thrusts cutting unlithified sediments in mtds display more variable displacement and more pronounced displacement gradients toward fault tips compared to thrusts cutting lithified sequences

plasma characteristics of polar cap f layer arcs first results are reported of a comprehensive campaign to measure ionospheric structure and dynamics of nighttime polar cap f layer or f region arcs airborne optical and digital ionosonde data were collected simultaneously with ground based incoherent scatter radar data continuously over many hours in time and 500 to 1000 km in space polar cap f region sub visual auroral arcs which are commonly observed during quiet magnetic conditions are found to represent boundaries or shears in the polar cap plasma circulation pattern f region electron concentration enhancements are found in these features and can be of significance to polar thermospheric circulation composition and thermal structure the quiet polar ionosphere is so structured that high time resolution intensified optical images of thermospheric emmissions can make a major contribution to interpretation of incoherent scatter radar data

lithology of the long sediment record recovered by the icdp dead sea deep drilling project dsddp abstract the sedimentary sections that were deposited from the holocene dead sea and its pleistocene precursors are excellent archives of the climatic environmental and seismic history of the levant region yet most of the previous work has been carried out on sequences of lacustrine sediments exposed at the margins of the present day dead sea which were deposited only when the lake surface level rose above these terraces e g during the last glacial period and typically are discontinuous due to major lake level variations in the past continuous sedimentation can only be expected in the deepest part of the basin and therefore a deep drilling has been accomplished in the northern basin of the dead sea during winter of 2010 2011 within the dead sea deep drilling project dsddp in the framework of the icdp program approximately 720 m of sediment cores have been retrieved from two deep and several short boreholes the longest profile 5017 1 revealed at a water depth of 300 m reaches 455 m below the lake floor blf i e to 1175 m below global mean sea level and comprises approximately the last 220 240 ka the record covers the upper part of the amora penultimate glacial the last interglacial samra the last glacial lisan and the holocene ze elim formations and therewith two entire glacial interglacial cycles thereby for the first time consecutive sediments deposited during the mis 6 5 5 4 and 2 1 transitions were recovered from the dead sea basin which are not represented in sediments outcropping on the present day lake shores in this paper we present essential lithological data including continuous magnetic susceptibility and geochemical scanning data and the basic stratigraphy including first chronological data of the long profile 5017 1 from the deep basin the results presented here a focus on the correlation of the deep basin deposits with main on shore stratigraphic units thus providing a unique comprehensive stratigraphic framework for regional paleoenvironmental reconstruction and b highlight the outstanding potential of the dead sea deep sedimentary archive to record hydrological changes during interglacial glacial and transitional intervals

upslope verging back thrusts developed during downslope directed slumping of mass transport deposits acknowledgements sm acknowledges the israel science foundation isf grant no 1436 14 and the ministry of national infrastructures energy and water resources grant 214 17 027 rw was supported by the israel science foundation isf grant no 1245 11

distinguishing thrust sequences in gravity driven fold and thrust belts abstract piggyback or foreland propagating thrust sequences where younger thrusts develop in the footwalls of existing thrusts are generally assumed to be the typical order of thrust development in most orogenic settings however overstep or break back sequences where later thrusts develop above and in the hangingwalls of earlier thrusts may potentially form during cessation of movement in gravity driven mass transport deposits mtds in this study we provide a detailed outcrop based analysis of such an overstep thrust sequence developed in an mtd in the southern dead sea basin evidence that may be used to discriminate overstep thrusting from piggyback thrust sequences within the gravity driven fold and thrust belt includes upright folds and forethrusts that are cut by younger overlying thrusts backthrusts form ideal markers that are also clearly offset and cut by overlying younger forethrusts portions of the basal detachment to the thrust system are folded and locally imbricated in footwall synclines below forethrust ramps and these geometries also support an overstep sequence however new short cut basal detachments develop below these synclines indicating that movement continued on the basal detachment rather than it being abandoned as in classic overstep sequences further evidence for synchronous thrusting where movement on more than one thrust occurs at the same time is provided by displacement patterns on sequences of thrust ramp imbricates that systematically increases downslope towards the toe of the mtd older thrusts that initiate downslope in the broadly overstep sequence continue to move and therefore accrue greater displacements during synchronous thrusting our study provides a template to help distinguish different thrust sequences in both orogenic settings and gravity driven surficial systems with displacement patterns potentially being imaged in seismic sections across offshore mtds

distinguishing coeval patterns of contraction and collapse around flow lobes in mass transport deposits abstract gravity driven mass transport deposits mtds form by the downslope directed movement of sediment associated with slope failure simple models suggest that extension forms at the upslope head area contraction is focussed in the downslope toe of the slump while differential shear associated with strike slip is restricted to the lateral margins of the slump although the head and toe are considered to be dominated by layer parallel shear lps differential layer normal shear lns may be generated around the lateral margins of slumps and potentially also within mtds where flow has been separated into different lobes despite this realisation that lns must form there has been little work into the geometries and spatial relationships of resulting structures using the late pleistocene lisan formation exposed around the dead sea basin as our case study we examine detailed

gypsum as a monitor of the paleo limnological hydrological conditions in lake lisan and the dead sea the isotopic composition and mass balances of sources and sinks of sulfur are used to constrain the limnological hydrological evolution of the last glacial lake lisan 70 14 ka bp and the holocene dead sea lake lisan deposited large amounts of primary gypsum during discrete episodes of lake level decline this gypsum which appears in massive or laminated forms displays 34s values in the range of 14 28 in addition lake lisan s deposits the lisan formation contain thinly laminated and disseminated gypsum as well as native sulfur which display significantly lower 34s values 26 to 1 and 20 to 10 respectively the calculated bulk isotopic compositions of sulfur in the sources and sinks of lake lisan lacustrine system are similar 34s 10 indicating that freshwater sulfate was the main source of sulfur to the lake the large range in 34s found within the lisan formation 26 to 28 is the result of bacterial sulfate reduction bsr within the anoxic lower water body the monimolimnion and bottom sediments of the lake precipitation of primary gypsum from the ca chloride solution of lake lisan is limited by sulfate concentration which could not exceed 3000 mg l the upper gypsum unit deposited before ca 17 15 ka is the thickest gypsum unit in the section and displays the highest 34s values 25 28 yet our calculations indicate that no more than a third of this unit could have precipitated directly from the water column this implies that during the lake level decline that instigated the precipitation of the upper gypsum unit significant amounts of dissolved sulfate had to reach the lake from external sources we propose a mechanism that operated during cycles of high low stands of the lakes that occupied the dead sea basin during the late pleistocene during high stand intervals i e marine isotopic stages 2 and 4 lake brine underwent bsr and infiltrated the lake s margins and adjacent strata as lake level dropped these brines carrying 34s enriched sulfate were flushed back to the shrinking lake and replenished the water column with sulfate thereby promoting massive gypsum precipitation the holocene dead sea precipitated relatively small amounts of primary gypsum mainly in the form of thin laminae 34s values of these laminae and disseminated gypsum are relatively constant 15 0 7 and are close to present day lake composition this reflects the lower supply of freshwater to the lake and the limited bsr activity during the arid holocene time and possibly during former arid interglacials in the levant

rapid climate change during the early holocene in western europe and greenland based on microfacies analyses of seasonally laminated varved sediments from lake holzmaar germany we report evidence of decadal to century scale climate variability during the early holocene the shifts in climate are documented in the thickness variations and changes in the composition of the varves in response to subtle shifts in limnological conditions the close similarity between the holzmaar varve record and the grip oxygen isotope record during 7 4 9 0 calendar cal ka suggests that the high frequency climatic variations in both regions were controlled by the same mechanism our more detailed studies covering the central 409 yr period 7 846 8 255 cal ka encompassing the 8 2 ka event document for the first time on a seasonal scale the changing precipitation regimes in western europe during these climate shifts we show i that winters were drier and summers shorter and cooler in western europe during colder periods in greenland ii in contrast to the present day climate in the holzmaar

paleoenvironmental reconstruction of a saline lake in the tertiary evidence from aragonite laminae in the northern tibet plateau abstract the origin of aragonite has long been debated because it is precipitated and preserved under specific conditions aragonite laminae first found from eocene to miocene strata in the western qaidam basin northern tibet plateau contain much information on paleolake signatures mineralogical and geochemical analyses were conducted on alternating yellowish and grayish aragonite layers the yellowish layers are mainly composed of aragonite crystals while the grayish layers contain less aragonite and fewer organic remnants that accumulate among debris with sporadic framboidal pyrite the 13c values of yellowish layers are remarkably positive by approximately 4 01 vpdb and the 18o values are slightly negative compared with base data of the qaidam basin considering the 12co2 absorption of algal blooms positive excursions of 13c shown in aragonite indicate high 13c values in depositional water therefore a seasonal algal influenced inorganic origin is proposed to explain the formation of aragonite laminae during warm seasons mg ca ratios are elevated because of evaporation effects the algal blooms decrease the co2 content leading to high ph values these conditions promote the rapid crystal growth of aragonite instead of other carbonate minerals slightly negative 18o values in yellowish layers are interpreted as the result of intense inflow during warm seasons which leads to less precipitation of organic matter and debris the grayish layers in cold seasons are the opposite from the eocene to oligocene the progressively decreasing 18o values of aragonite reflect global cooling during this time a conspicuously positive step in 18o values indicates an arid environment coinciding with the uplift of the himalaya from the oligocene to lower miocene the results from this study show that understanding of aragonite in the qaidam basin is essential to reconstruct the high resolution paleoenvironment and to reveal the tertiary evolution of paleoclimates in the northern tibet plateau

strontium isotopic chemical and sedimentological evidence for the evolution of lake lisan and the dead sea precise strontium isotope ratios combined with chemical analyses and sedimentological information are used to monitor the water sources and the evolution of the dead sea and its late pleistocene precursor lake lisan 70 18 kyr b p the materials analyzed include bulk aragonite water leached soluble salts and residual aragonite and gypsum from the lisan formation in the perazim valley near the sw shore of the dead sea the residual aragonite and the associated soluble salts display systematic fluctuations in 17sr86sr ratios between 0 70803 and 0 70806 and from 0 70805 to 0 70807 respectively in individual soluble salt residual aragonite pairs the soluble salt displays a higher 87sr86sr ratio gypsum samples yield 17sr86sr ratios similar to the soluble salts from adjacent layers in the section this shows that in individual samples the source of sr in aragonite was distinct from that in soluble salts and the gypsum the sterility of the lisan sediments their strictly nonbioturbated fine lamination and their high content of chloride salts indicate that lake lisan was a saline or even hypersaline water body in the absence of alternative sources of hco3 and s042 the abundance of primary aragonite and gypsum in the lisan column reflects an import of very large volumes of freshwater into the otherwise saline lake resulting in a density stratification of this water body the history of the upper water layer and that of the lower brine is reflected in the chemical and strontium isotope composition of the aragonite and in that of the associated soluble salts and in the gypsum samples respectively whereas the bicarbonate and much of the ca2 required for aragonite crystallization were supplied by the freshwater the complementary ca2 and sr 2 were added by the lower brine the upper water layer of lake lisan acted as a so42 capacitor during the lake s rise periods it was removed therefrom as prominent gypsum beds upon climatic induced drier period mixing or even complete overturn of the lake the evolution of lake lisan took place between two distinct modes the first was characterized by an extensive supply of freshwater and resulted in a rise of the lake s level a density layered structure and precipitation of aragonite the second mode was marked by a diminishing freshwater input resulting in mixing or complete overturn of its water and precipitation of gypsum these two modes reflect the climatic evolution of the region in the late pleistocene which fluctuated between drier and wetter periods the transition to the holocene is accompanied by the dry up of lake lisan and its contraction to the present dead sea

evidence from lake lisan of solar influence on decadal to centennial scale climate variability during marine oxygen isotope stage 2 documentation of short term climate variability during the glacial period has been limited by the availability of well dated high resolution archives here we present a paleoclimate reconstruction from varved lacustrine sediments of lake lisan dead sea rift for ca 26 2 17 7 calendar ka the age is based on a floating varve chronology anchored to radiometric dates our reconstruction indicates that small ice rafting events a b c and d as well as heinrich events in the north atlantic are associated with the eastern mediterranean arid intervals study of seasonal sublaminae yields evidence of several additional decadal to century scale arid events that correlate with cooler temperatures at higher latitudes analyses in the frequency domain indicate the presence of periodicities centered at 1500 yr 500 yr 192 yr 139 yr 90 yr and 50 60 yr suggesting a solar forcing on climate

revised chronology of the icdp dead sea deep drill core relates drier wetter drier climate cycles to insolation over the past 220 kyr abstract the dead sea deep drilling project drilled 456 meters into the deepest floor of the dead sea and recovered a record of the past 220 kyr of the levant hydroclimate history that is marine isotope stages 1 7 including the last three interglacials and the last two glacials we present an updated chronology of the core from dsddp hole 5017 1 a from the dead sea s deepest basin that refines our previous chronology torfstein et al 2015 based on new information the updated chronology uses the following approaches 1 radiocarbon ages of kitagawa et al 2017 2 correlation of specific layers in the core with u th dated sediments on the dead sea margin particularly during the interval of glacial lake lisan mis 2 3 4 3 tuning of the 18o data of dsddp core aragonite to the u th dated oxygen isotopes of regional cave speleothems and 4 tuning of the dsddp aragonite 18o data to summer insolation curves when the cave 18o chronology is less clear the updated chronology reveals a strong relationship between the sedimentary facies comprising the core and northern hemisphere summer insolation variations it shows that sequences of sediments marking drier wetter drier climate conditions in the lake s watershed e g salt muds salt respectively appear across the flank peak flank segments of several summer insolation peaks in particular the transition from drier to wetter sedimentary facies during mid latitude insolation peaks coincides with the intervals of sapropel conditions in the mediterranean reflecting enhanced nile flow due to intense african monsoonal conditions and marking the impact of the tropical precession cycles on eastern mediterranean hydroclimate this pattern was lost during mis 2 3 4 when mostly sequences of primary aragonite are punctuated by gypsum precipitation during heinrich events marking the strong impact of the north atlantic on the last glacial levant hydroclimate

calibration of the 14c time scale to 40 ka by 234u 230th dating of lake lisan sediments last glacial dead sea a new comparison of 14c dates with 234u 230th ages is presented of aragonites from lake lisan the last glacial dead sea between 20 52 cal ka bp the lisan data are coincident with the coral based 14c calendar age calibration through the continuous portion of the curve to 23 5 cal ka bp and with the additional checkpoints at 30 and 40 cal ka bp the agreement with the corals provides evidence for the accuracy of the u th and 14c ages and indicates that lisan aragonites can potentially be used to generate a nearly continuous record of the atmospheric 14c variations through this crucial time interval the lisan data are compared with other records older than 25 cal ka bp from lake suigetsu japan north atlantic foraminifera south african cave deposits and tufa from spain over some age intervals the records show broad agreement over other intervals they diverge all agree that 14c ages were 2 5 0 5 ka younger than calendar ages between 20 32 cal ka bp for ages 32 cal ka bp the lake suigetsu data indicate small differences between 14c ages and calendar ages of less than 1 5 ka the other records broadly agree that 14c ages are too young by 3 1 ka from 32 39 cal ka bp at 40 cal ka bp the foraminifera show equal 14c and calendar ages while the corals lisan aragonites and the spanish tufa indicate a large age difference of 4 5 ka a recent paleomagnetic study of the lisan formation indicates that the high calendar 14c age difference at 40 cal ka bp may be associated with the laschamp paleomagnetic excursion

modelling of dripwater hydrology and hydrogeochemistry in a weakly karstified aquifer bath uk implications for climate change studies abstract a better knowledge of dripwater hydrology in karst systems is needed to understand the palaeoclimate implications of temporal variations in mg ca and sr ca of calcareous cave deposits quantitative modelling of drip hydrology and hydrochemistry was undertaken at a disused limestone mine brown s folly mine in sw england overlain by 15 m of poorly karstified jurassic limestones with sub vertical fracturing enhanced by proximity to an escarpment discharge was monitored at 15 sites intermittently from the beginning of 1996 and every 10 20 days from later 1996 to early 1998 samples for hydrochemical parameters ph alkalinity cations anions fluorescence were taken corresponding to a sub set of these data and supplemented by bedrock and soil sampling limited continuously logged discharge and soil water observations three sites covering the range of discharge approximately 1 l s 1 to 1 ml s 1 maximum discharge and hydrochemical behaviours were studied in more detail a quantitative flow model was constructed based on two parallel unit hydrographs responsive and relatively unresponsive to discharge events respectively the linear response and conservative mixing assumptions of the model were tested with hydrogeochemical data dripwaters at many of sites are characterized by evidence of prior calcite precipitation in the flowpath above the mine which in the higher discharging sites diminishes at high flow also at low flow rates dripwaters may access seepage reservoirs enriched in mg and or sr dependent on the site the discharge at all three sites can be approximated by the flow model but in each case hydrochemical data show violations of the model assumptions all sites show evidence of non conservative mixing and there are temporal discontinuities in behaviour which may be stimulated by airlocks generated at low flow enhanced mg ca and sr ca often do relate to low flow conditions but the relationships between climate and hydrogeochemical response are non linear

a window into africa s past hydroclimates the sisal_v1 database contribution africa spans the hemispheres from temperate region to temperate region and has a long history of hominin evolution although the number of quaternary palaeoclimatic records from the continent is increasing much of the history of spatial and temporal climatic variability is still debated speleothems as archives of terrestrial hydroclimate variability can help reveal this history here we review the progress made to date with a focus on the first version of the speleothem isotopes synthesis and analysis sisal database the geology of africa has limited development of large karst regions to four areas along the northern coast bordering the mediterranean eastern africa and the horn of africa southwestern africa and southern africa exploitation of the speleothem palaeoclimate archives in these regions is uneven with long histories of research e g in south africa but large areas with no investigations such as west africa consequently the evidence of past climate change reviewed here is irregularly sampled in both time and space nevertheless we show evidence of migration of the monsoon belt with enhanced rainfall during interglacials observed in northeast africa southern arabia and the northern part of southern africa evidence from eastern africa indicates significant decadal and centennial scale rainfall variability in northwestern and southern africa precession and eccentricity influence speleothem growth largely through changing synoptic storm activity

stable isotope proxy records in tropical terrestrial environments abstract the tropics refers to an area that is loosely equatorial characterized by relatively high temperatures at low altitude comparatively low seasonal contrast in temperatures and generally high or highly seasonal rainfall the stable isotopes of carbon oxygen and hydrogen are increasingly important tools of relevance to understanding trajectories and mechanisms of past environmental change in the tropics in the case of carbon this is because at the broadest level the carbon isotope composition of organic and carbon containing inorganic proxy materials formed in the tropics can be read as being derived from the balance between c3 tree and c4 grass photosynthesis hence providing a relative measure of vegetation type and indirectly climate likewise changes in the oxygen and hydrogen isotope composition of many proxy materials again at the broadest level can be read as indicative of changes in hydrological conditions and or altitude in the past this review provides an entry point into the literature relating to the use of stable isotopes as terrestrial environmental proxies for past environmental change with a focus on the measurement and interpretation of stable isotope data from the wide range of proxy materials preserved in tropical environments

stable isotopes in east african precipitation record indian ocean zonal mode observational stable isotope data and model simulations show that the 18 o composition of precipitation in east africa is closely related to the coupled ocean atmosphere system over the indian ocean during the rainy seasons 18 o is a very sensitive recorder of the indian ocean zonal mode iozm the link between 18 o and the iozm is established through adjustments in the large scale overturning circulation over the indian ocean and associated changes in convective activity and precipitation over east africa the iozm is recorded as significant departures in 18 o not only over east africa but as a dipole mode with opposite sign to the east and west of the indian ocean

long term earthquake clustering a 50 000 year paleoseismic record in the dead sea graben the temporal distribution of earthquakes in the dead sea graben is studied through a 50 000 year paleoseismic record recovered in laminated sediments of the late pleistocene lake lisan paleo dead sea the lisan represents more than 10 times the 4000 years of historical earthquake records it is the longest and most complete paleoseismic record along the dead sea transform and possibly the longest continuous record on earth it includes unique exposures of seismite beds earthquake induced structures associated with slip events on syndepositional faults the seismites are layers consisting of mixtures of fragmented and pulverized laminae the places where the seismites abut syndepositional faults are interpreted as evidence for their formation at the sediment water interface during slip events on these faults thicker sediment accumulation above the seismites in the downthrown blocks indicates that a seismite formed at the water sediment interface on both sides of the fault scarps modern analogs and the association with surface ruptures suggest that each seismite formed during a m l 5 5 earthquake the 230 th 234 u ages of a columnar section obtained by thermal ionization mass spectrometry give a mean recurrence time of 1600 years of m l 5 5 earthquakes in the dead sea graben the earthquakes cluster in 10 000 year periods separated by quiet periods of similar length this distribution implies that a long term behavior of the dead sea transform should be represented by a mean recurrence of at least 20 000 year record this observation has ramifications for seismic hazard assessment based on shorter records

reconstructing low levels of lake lisan by correlating fan delta and lacustrine deposits abstract reconstruction of paleo shorelines of lake lisan the late pleistocene precursor of the dead sea is based on sequence stratigraphy of fan delta and lacustrine deposits that are exposed at the perazim valley southwest of the dead sea the shoreline sediments are physically correlated with lacustrine aragonites their ages are determined by u series dating to establish a lake level curve for the time interval between 55 and 35 kyr during most of this period lake lisan was at a relatively low level which fluctuated between 280 and 290 m below sea level m bsl the minimum lake stand 330 m bsl was reached at 47 kyr and lasted for 3 4 kyr this episode is marked by a depositional hiatus in the section and formation of an erosional channel the studied period correlates with the global marine isotope stage 3 the low stand of lake lisan during most of this period indicates relative dry climatic conditions in the region

oceanic link between abrupt changes in the north atlantic ocean and the african monsoon abrupt changes in the african monsoon which have been recorded throughout the late pleistocene and early holocene epochs tend to coincide with changes in north atlantic thermohaline circulation a numerical simulation shows that the interaction between thermohaline circulation in the north atlantic ocean and wind driven currents in the topical atlantic ocean contributes to the rapidity of african monsoon transitions during abrupt climate change events

ams radiocarbon dating of annually laminated sediments from lake holzmaar germany ams radiocarbon ages have been determined on terrestrial macrofossils selected from the annually laminated sediments of lake holzmaar germany the radiocarbon chronology of this lake covers the last 12 6 ka comparison of the radiocarbon dated varve chronology with tree ring data shows that an additional 878 years have to be added to the varve chronology the corrected c 14 varve chronology of holzmaar reaches back to ca 13 8 ka cal bp and compares favourably with the results from soppensee switzerland hajdas et al 1993 the corrected ages for the onset and the end of the younger dryas biozone are 11 940 cal bp and 11 490 cal bp respectively the ash layer of the laacher see volcanic eruption is dated at 12 201 224 cal bp and the ulmener tephra layer is dated at 10 904 cal bp

applications of stalagmite laminae to paleoclimate reconstructions comparison with dendrochronology climatology abstract laminated stalagmites observed in either ultra violet or visible light or recognized via trace elements are now widely recognized as a common deposition form annually laminated stalagmites should be expected in caves which have an overlying climate that has a strong seasonality similar climate zones to where trees grow with distinct annual rings continuous laminated stalagmite chronologies up to several thousand years should be expected where some mixing of stored water occurs such stalagmites can be used to reconstruct climate particularly through variations in lamina width such climate records would be relatively damped by mixing of event water with stored groundwater constraining the amount of high frequency climate signals contained in the stalagmite but relatively long continuous lamina sequences permit the preservation of low frequency centennial scale climate signals this contrasts with numerous tree ring climate records which are frequently limited in preserving multi centennial trends due to the necessary removal of age related noise from relatively short tree segments laminated stalagmites and tree rings should therefore to some degree provide complementary climate information appropriate methods for compiling stalagmite layer chronologies and climatologies are presented

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

hydrological uncertainties in the modelling of cave drip water δ18o and the implications for stalagmite palaeoclimate reconstructions abstract in this paper we review our current understanding of karst drip water hydrology emphasising the extent of non linear and non stationary process dynamics that render stalagmite palaeoclimate reconstructions using a statistical pseudo proxy approach difficult to implement we outline an approach to attribute the uncertainty that arises specifically as a consequence of variable water routing through the overlying soil epikarst and karst aquifer this is based upon the development of a monthly lumped parameter karst hydrological model which we use to demonstrate the range of modelled drip water discharges possible from a single climate input refinement of the model to include precipitation 18 o enables us to determine the theoretical range in drip water and stalagmite 18 o for three sites with contrasting climates northern temperate nw scotland monsoonal ethiopia and mediterranean gibraltar for actual climate monthly mean temperature monthly total precipitation monthly mean precipitation 18 o we compare model simulations of karst groundwater storage and drip water 18 o to demonstrate our ability to model different climate regimes realistically we also investigate the 18 o variability associated with specific karst water reservoirs that differ in their capacity and drainage mechanisms 18 o variability is then compared to stalagmite 18 o record from the three regions for the last 45 years we conclude by reviewing the implications of our hydrological model for stalagmite 18 o quaternary palaeoclimate reconstructions over different timescales and sampling resolutions

investigation of the stable isotope fractionation in speleothems with laboratory experiments many speleothems show evidence for calcite precipitation under disequilibrium conditions to improve the understanding of these kinetic processes several laboratory experiments were performed to study the fractionation of stable oxygen and carbon isotopes during the precipitation of calcite carbonate was precipitated under controlled conditions from both a body of standing water beaker experiments and a solution flowing along a channel channel experiments at a relative humidity of 100 slow degassing of co2 simulated by the beaker experiments results in 18o values in equilibrium with the solution in contrast the 13c values show a significant enrichment inversely proportional to the height of the solution in the beakers fast degassing of co2 simulated by the channel experiments showed an enrichment of both 13c and 18o and a slope of 13c 18o of 1 4 0 6 these results represent experimental evidence for the hendy effect which is manifested in i a progressive increase in 18o and 13c away from the growth axis and ii a positive correlation between 18o and 13c along a single growth layer of a stalagmite

u th dating of lake lisan late pleistocene dead sea aragonite and implications for glacial east mediterranean climate change u series dating can be an effective means to obtain accurate and precise ages on quaternary carbonates however most samples require a correction for u and th in admixed detritus this complication is often addressed through generation of u th isochrons requiring analyses of several coeval samples in addition presence of water derived hydrogenous th in the carbonate can cause inaccuracies in isochron ages this study reports a high resolution u series chronology of sediments deposited by lake lisan the last glacial precursor of the dead sea the strategy employed combines multiple measurements from a few stratigraphic heights and fewer analyses from many heights in a single described and measured section the resulting chronology is based on ages at 22 heights in a 40 m thick section covering the interval of 70 14 calendar ka bp the effects of admixed detritus are evaluated using trace elements nearly pure aragonite samples indicated by very low abundances of insoluble elements such as nb and zr were found to contain hydrogenous th which causes the uncorrected u 230th age of a modern sample to be 2 5 ka nevertheless accurate ages have been obtained by correcting for the detrital and aqueous interferences the resulting ages are in stratigraphic order and their accuracy is evidenced by consistency of lisan formation u series and 14c ages with the coral based calendar radiocarbon age calibration the u th ages provide a context to unravel the limnological history of lake lisan boundaries between the lower middle and upper stratigraphic units correspond to the mis 4 3 and 3 2 transitions respectively during mis 2 and 4 the lake generally showed a stable two layer configuration and a positive fresh water balance reflected by deposition of laminated aragonite detritus dry intervals during mis 2 and 4 are indicated by thick gypsum layers and an inferred depositional hiatus which are temporally associated with heinrich events h1 at 17 ka and h6 at 65 ka respectively during mis 3 the lake level was unstable with intermittent dry periods indicated by abundant clastic layers and a significant hiatus between 43 49 ka clastic layers are associated with dansgaard oeschger events during mis 3 and indicate lake level declines during abrupt northern hemisphere warmings overall the climate of the eastern mediterranean region shows a strong linkage to the northern hemisphere climate with increasing lake size and stability during cold periods and fluctuations and dessication during warmings and heinrich events

a high resolution multi proxy stalagmite record from mechara southeastern ethiopia palaeohydrological implications for speleothem palaeoclimate reconstruction an annually laminated stalagmite from southeastern ethiopia grew for 443 8 yr starting at 5023 yr bp 160 yr as determined by lamina tuned u th dating the speleothem shows three growth phases 1 an initial phase where the stalagmite has a candlestick shape deposited by relatively slow rate drip water 2 a middle growth phase where laminae grow on the flanks suggesting faster drip rates and 3 a final growth phase where the speleothem becomes narrower owing to a decrease in drip water supply towards the end of deposition morphometry annual growth rate fluorescence index and 234u 238u isotope ratio show marked differences between the growth phases while 13c and 18o do not show significant variation except within the third phase towards the top of the stalagmite where they have higher values the study indicates that the multiproxy approach is crucial as the different proxies respond to single climate forcing in different manners our results can be widely applied to speleothem studies distinguishing the relative importance of the various proxies in recording cave external climate hydrology and cave internal e g evaporation processes copyright 2006 john wiley sons ltd

climatic change recorded in the sediments of the chew bahir basin southern ethiopia during the last 45 000 years abstract east african paleoenvironments are highly variable marked by extreme fluctuations in moisture availability which has far reaching implications for the origin evolution and dispersal of homo sapiens in and beyond the region this paper presents results from a pilot core from the chew bahir basin in southern ethiopia that records the climatic history of the past 45 ka with emphasis on the african humid period ahp 15 5 ka calbp geochemical physical and biological indicators show that chew bahir responded to climatic fluctuations on millennial to centennial timescales and to the precessional cycle since the last glacial maximum potassium content of the sediment appears to be a reliable proxy for aridity showing that chew bahir reacted to the insolation controlled humidity increase of the ahp with a remarkably abrupt onset and a gradual termination framing a sharply defined arid phase 12 8 11 6 ka calbp corresponding to the younger dryas chronozone the chew bahir record correlates well with low and high latitude paleoclimate records demonstrating that the site responded to regional and global climate changes

decadal scale rainfall variability in ethiopia recorded in an annually laminated holocene age stalagmite an annually laminated uranium series dated holocene stalagmite from southeast ethiopia has been analysed for growth rate and 13c and 18o variations at annual to biennial resolution in order to provide the first long duration proxy record of decadal scale rainfall variability in this climatically sensitive region our study site 10 n is climatically influenced by both summer june august and spring march may rainfall caused by the annual movement of the inter tropical convergence zone itcz and modulated by large scale anomalies in the atmospheric circulation and in ocean temperatures here we show that stalagmite growth episodic throughout the last 7800 years demonstrates decadal scale 8 25 yr variability in both growth rate and 18o a hydrological model was employed and indicates that this decadal variability is due to variations in the relative amounts of rainfall in the two rain seasons our record unique in its combination of length a total of 1000 years annual chronology and high resolution 18o shows for the first time that such decadal scale variability in rainfall in this region has occurred through the holocene which implies persistent decadal scale variability for the large scale atmospheric and oceanic driving factors

recurrence pattern of holocene earthquakes along the dead sea transform revealed by varve counting and radiocarbon dating of lacustrine sediments abstract a high resolution holocene seismic history of the dead sea transform dst is established from laminated sedimentary cores recovered at the shores of the dead sea radiocarbon dating and annual laminae counting yield excellent agreement between disturbed sedimentary structures identified as seismites and the historical earthquake record all recent and historical strong events of the area were identified including the major earthquakes of a d 1927 1837 1212 1033 749 and 31 b c the total of 53 seismites recognized along the entire holocene profile indicate varying recurrence intervals of seismic activity between a few and 1000 years with a conspicuous minimum rate at 2100 31 b c and a noticeable maximum during the past six to eight centuries most of the epicenters of the correlated earthquakes are situated very close to the dead sea within 150 km or up to 400 km north of it along the dst between 1000 b c and a d 1063 and from a d 1600 to recent time the epicenters are all located on the northern segment of the dst whereas prior to 1000 b c and between a d 1000 and 1600 they appear to scatter along several segments of the dst we establish how the local intensity exerts a control on the formation of seismites at historically estimated intensities greater than vii all well documented earthquakes are correlated whereas at intensities smaller than vi none are matching the periods with enhanced earthquake rate along the dst correlate with those along the north anatolian fault as opposed to the intervening east anatolian fault this may indicate some elastic coupling on plate boundary scale that may also underlie escape and extrusion tectonics typical of continental collision

bed parallel slip identifying missing displacement in mass transport deposits abstract bed parallel slip bps where neighbouring beds slide past one another along bedding planes is notoriously difficult to identify without reference to pre existing features such as steep faults or dykes that act as markers to record bps offset while bps is intuitively thought to operate during downslope sliding of mass transport deposits mtds in sedimentary basins there is a conspicuous lack of supporting outcrop or seismic data to corroborate this and bps displacement may therefore have remained unaccounted for this study addresses this gap in knowledge by investigating late pleistocene mtds developed around the dead sea basin and provides the first detailed analysis of bps that pervades a gravity driven setting in particular we examine the role of bps that crosscuts earlier normal and reverse faults that act as markers to allow metre scale patterns of horizontal displacement to be identified in mtds the studied bps always forms with a consistent top to the east sense of offset that corresponds with gravity driven downslope movement towards the depo centre of the basin bps frequently develops adjacent to competent detrital rich beds and forms discrete glide planes with little or no visible deformation in sediments on either margin although detachment folds are occasionally developed above the slip plane and confirm directions of easterly movement early downslope dipping normal faults that are cut by later bps planes results in older over younger stratigraphic relationships across the bps surface together with sawtooth patterns where multiple bps planes have developed conversely early upslope dipping normal faults that are cut by bps create younger over older stratigraphic relationships combined with missing section and staircase patterns where multiple bps planes exist as bps in sub horizontal sequences does not have a vertical component of displacement it may be examined in terms of horizontal heave bps increases heave in upslope dipping normal faults whereas it reduces heave in downslope dipping normal faults and may even become negative where sections are repeated across sawtooth profiles in addition bps increases heave in upslope dipping reverse thrust faults and reduces heave across downslope dipping backthrusts although individual bps planes may have limited displacement the net consequence of multiple planes of bps that form in the shallow subsurface is to distort patterns and estimates of extension and contraction across fault zones in mtds

varve counting reveals high resolution radiocarbon reservoir age variations in palaeolake lisan the laminated lacustrine sediments deposited in the last glacial lake lisan represent annual deposits of primary aragonite and silty detritus that reflect the annual supply of bicarbonate bearing freshwater to the lake a varve counting curve was constructed for the time interval of ca 17 4 22 cal ka bp based on aragonite u th and atmospheric radiocarbon ages of organic debris recovered from the studied section radiocarbon in the primary evaporitic aragonite comprises both atmospheric and old carbon reflecting the reservoir age the aragonite reservoir ages were determined by comparing the aragonite radiocarbon dates to the varve counting curve and are found to lie in the range 1900 600 a and display a continuous decline this opens the possibility for high annual resolution monitoring of the reservoir age similar in quality to tree ring counting during the upper part of marine isotope stage mis 2 our work also demonstrates that a uniform reservoir age correction is inappropriate when determining the chronology of short term climate events in lacustrine environments copyright 2009 john wiley sons ltd

dead carbon in stalagmites carbonate bedrock paleodissolution vs ageing of soil organic matter implications for 13c variations in speleothems twenty one 14c accelerator mass spectrometric analyses were obtained for three holocene stalagmites from the uamh an tartair cave sutherland scotland in order to estimate the past dead carbon proportion dcp results show that the dcp increases from 22 to 38 from 3780 years ago to the present because 13c variation is small within each sample it is concluded that this dcp increase is the product of the ageing of soil organic matter related to peat bog development above the cave that produced older soil co2 and not from a more intense dissolution of the surrounding carbonates which would have led to a 13c increase comparison with samples from other sites in europe shows no intersite correlation between dcp and 13c but a relatively good intersite correlation is observed between dcp and average site temperature thus temperature may be a major factor controlling the production of old soil organic matter co2 and therefore the dead carbon content of seepage water in contrast to the scotland stalagmites two other holocene samples from sites in southern france and belgium exhibit a good correlation between 13c and dcp which can be explained in terms of variations in the intensity of limestone dissolution consequently 13c variations observed in stalagmites are not always due to changes in the vegetation type c3 c4 as has been commonly assumed 13c 12c variations in speleothem calcite may also be controlled by the soil organic matter age and in some cases by the intensity of the limestone dissolution conversely a largely constant speleothem 13c signal as observed for the scotland stalagmites does not necessarily imply that surface climate and vegetation conditions were stable since the dcp variations in this case are clearly related to the peat bog development during stalagmite growth