climate reconstruction for the holsteinian interglacial in eastern poland and its comparison with isotopic data from marine isotope stage 11 abstract sediments of palaeolakes located in eastern poland represent the holsteinian interglacial and the initial part of the succeeding saalian glaciation they consist of 55 m thick lake marl and calcareous gyttja deposits reconstruction of climate during this part of the pleistocene was carried out by the analyses of oxygen and carbon isotope ratios of carbonates palynological data al and ca content of sediments isotope ratios and palynological results give in some cases contradictory results 18o ratios from lake ossowka eastern poland indicate relatively cool conditions at the climatic optimum of the holsteinian interglacial low ratios may have been caused by increased precipitation that led to high stands of the lake level during the initial stages of the following glaciation the 18o and 13c ratios increased probably resulting from low water level and strong evaporation in cool and dry climate phases additionally high al contents indicate high allochthonous siliciclastic input high ca concentrations indicate autochthonous carbonate precipitation from the lake epilimnion the combined climate indicators for the holsteinian interglacial in eastern poland suggest that this temperate episode corresponds to marine isotope stage 11 mis 11 of the north atlantic comparison of the continental record from eastern poland with the marine record from the north atlantic separated by about 2500 km indicates that even small climatic changes can be identified in genetically different deposits documenting the global nature of pleistocene climate trends

environmental changes during the holocene climatic optimum in central europe human impact and natural causes abstract the priority programme changes of the geo biosphere aimed to reconstruct the environmental history of central europe with emphasis on the time interval from 9000 to 5500 cal bp time slice ii coinciding with the holocene climatic optimum during this period the onset of human activities such as settlement agriculture and animal husbandry caused environmental changes studies of different landscape units in germany were carried out to identify these anthropogenically induced changes and to distinguish them from natural effects on the environmental system the investigated archives included laminated lake sediments fluvial sediments colluvia and soils speleothems peat and coastal sediments the different archives were examined using refined research methods including a variety of sedimentary and geochemical analyses together with pollen analysis and dating methods for the establishment of a reliable chronology the results of the various research groups are summarised and critically discussed based on these results the climatic optimum can be subdivided into three periods 1 the early atlantic from 9000 to 7500 cal bp with negligible human impact and stable environmental conditions 2 the late atlantic during early and middle neolithic from 7500 to 6300 cal bp with pollen evidence for vegetation changes but only negligible changes detectable in other proxy records and 3 the late atlantic during the younger neolithic jungneolithikum after 6300 cal bp with human impact observed in many archives and proxy records especially in the pollen record but also in lacustrine and fluvial sediments during the whole climatic optimum natural causes such as minor shifts of temperature did not induce substantial environmental changes though some changes such as temporary droughts may have facilitated and amplified the observed human impact

the early quaternary north sea basin the onset of the quaternary 2 58 ma corresponds to significant paleo environmental events such as the intensification and southward extension of northern hemisphere glaciation in the north sea basin a significant late cenozoic succession has been identified as a high resolution archive of paleo environmental changes during the pliocene and pleistocene however the identification of the base of the quaternary has been a long standing issue owing to lack of stratigraphic calibration this study incorporates continuous regional 3d seismic data with high quality chronostratigraphic markers to map the base quaternary surface at high resolution across the entire north sea depth conversion backstripping seismic geomorphology and sedimentation rate calculations are integrated to analyse the paleogeographical evolution of the north sea basin and its infill of c 83 10 3 km 3 of northward prograding marine to deltaic sediments the basin is 600 km long from sse to nnw and largely localized above residual topography of the mesozoic graben system during the earliest quaternary 2 58 2 35 ma paleo water depths were c 300 50 m and solid sedimentation rates calculated from 0 porosity c 32 km 3 ka 1 the base quaternary provides an important marker for further studies of the changing environment of the quaternary of nw europe as well as resource and shallow geohazard analysis supplementary material a base quaternary two way travel time structure map is available at https doi org 10 6084 m9 figshare c 3900343

patterns of variation in late glacial pollen stratigraphy along a northwest southeast transect through switzerland a numerical analysis palynological data from seven late glacial sites on a transect from the swiss plateau through the north and central alps to the south alps are analysed numerically constrained classification procedures were used to derive local pollen assemblage zones for each site detrended correspondence analysis was used to compare pollen stratigraphical similarities and differences within and between sites and to estimate the amount of palynological change at each site canonical correspondence analysis was used to display graphically patterns of variation between local zones within the sites and between the seven sites and to partition the total palynological variance into within site temporal variation and between site spatial variation the numerical results suggest that no two sites have identical late glacial pollen stratigraphies that the south alps site has a very different pollen stratigraphy compared with the other sites that the major spatial patterns of variation correspond to site location and thus that there was considerable variation in late glacial pollen rain along the transect just as there is today the total palynological variance is partitioned into 73 temporal variance 13 2 spatial variance and 13 8 unexplained variance the younger dryas event is poorly reflected in the south alps but is well reflected as a palynological revertence towards pre allerod assemblages at mid and high elevation sites in the north and central alps it is also well reflected as changes in pollen composition at one site on the swiss plateau but is poorly reflected at a nearby site on the swiss plateau

vegetation response to abrupt climate changes in western europe from 45 to 14 7k cal a bp the bergsee lacustrine record black forest germany

the mid holocene ulmus decline at diss mere norfolk uk a year by year pollen stratigraphy from annual laminations 3 m of annually laminated sediments were recovered from a small steep sided lake diss mere norfolk uk in an 8 cm section known to include the mid holocene elm decline the laminae were sampl

late glacial climatic oscillations as recorded in swiss lake sediments regional pollen assemblage zones for the late glacial period of the swiss plateau are introduced and defined they include four major zones artemisia juniperus hippophae betula pinus paz with several subzones pollen and oxygen isotope analyses on lacustrine sediments from several lakes in the area reveal four distinct phases of climatic oscillation in the time period of 13 000 9500 yr bp the first oscillation termed the aegelsee fluctuation occurs shortly before 12 000 yr bp and varve counts suggest its duration was ca 100 yr it is characterised by a short decrease in the oxygen isotopes as well as a short increase in nap associated with a depression in birch pollen values the second oscillation which occurs in the 18o record shortly before the deposition of the laacher see tephra ca 11 000 yr bp is termed the gerzensee fluctuation it occurs during a pine dominated phase and its vegetational effects cannot be determined palynologically the most prominent regressive phase is the younger dryas biozone ca 10 700 10 000 yr bp characterised by an increase in heliophilous nap and low 18o values the younger dryas biozone can often be subdivided palynologically into two parts a first part rich in grasses and juniper and a second part with higher filipendula and birch values during the preboreal biozone another distinct oscillation is evidenced only in the oxygen isotope ratios comparison of the swiss oxygen isotope profiles with the greenland dye 3 record suggests that not only the three major shifts in the 18o curves but also the minor ones are closely comparable suggesting some common climatic control

laminated sediments human impact and a multivariate approach a case study in linking palynology and archaeology steisslingen southwest germany abstract situated in the alpine foreland lake steisslingen provides sediments covering the last 16 000 sidereal years the exceptional value as an environmental archive is due to large laminated sections found in several long cores counting of organic varves allowed the establishment of a detailed varve based age model a high resolution pollen analysis for the period 5457 bc to 813 ad was carried out and compared with an archaeological mapping of a 5 km radius around lake steisslingen the combined interpretation of the palynological and archaeological evidence facilitates a reconstruction of the settlement history and the evolution of the landscape over the last eight millenia several important aspects of vegetational and settlement history are illuminated the mathematical ordination method of correspondence analysis is used to extract the main dimension of explanation from the pollen data a single curve is generated and thought to reflect human impact the validity of this assumed proxy is tested against the vegetational and archaeological evidence of the micro scale area since neolithic times from the steisslingen example we conclude that human impact is the most important and in a mathematical sense continuous factor in vegetational development of those landscapes which are settled since prehistoric times

the wurmian late glacial in lowland switzerland a synthesis is provided of late glacial 14 9 ka bp environmental changes in lowland switzerland the swiss plateau the chronology of deglaciation and subsequent developments in vegetation cov

varve chronology and palynology of the lateglacial in northwest germany from lacustrine sediments of hamelsee in lower saxony abstract the hamelsee is a dolina from a collapse over permian salt that occurred at the end of the pleniglacial it is more than 21 m deep and contains 18 m of lacustrine sediments the lateglacial sediments in the central part of the lake consist of 2 7 m from 15 to 17 7 m of sapropelic and silty muds which are mostly laminated and partly bioturbated minor slumps occur mainly during colder phases the subdivision of the lateglacial is based on pollen zones multidisciplinary studies of the microfacies from thin sections geochemistry pollen analysis and rotifer analysis allow environmental and palaeoclimatological interpretations to be made the biozones of the lateglacial and their boundaries are marked by rapid climatic changes though covering comparatively short periods of time they are not monotonous but characterized by minor internal climatic fluctuations the sediments of the meiendorf and oldest dryas are not laminated the allerod sediment is seasonally varved without interruption and encompasses 625 yr the eruption of the laacher see volcano 12 900 cal bp had an impact on the climate during the following 10 yr the transition from the allerod to the younger dryas took some 50 yr and it occurred 200 yr after the eruption of the laacher see volcano the abrupt change at the end of the lateglacial 11 560 cal bp occurred within less than 10 yr however many proxies reacted with a time lapse of 15 to 30 yr

high resolution lacustrine record of the late glacial holocene transition in central europe abstract in this paper we present the high resolution record of proxy climatic data in central europe during the final stages of the last deglaciation derived from the annually laminated sediments of lake go ciaz central poland the isotopic palynological and other microfossil data confirm sudden changes of climate at the onset and termination of the younger dryas completed within 150 and 70 years respectively in close agreement with the previous estimates derived from the polar ice cores and marine sediments in the upper yd some amelioration of climate took place already about 600 years before the main yd preboreal transition counting of annual varves in the lake sediments allows a direct estimate of the duration of the younger sdryas in central europe it lasted approximately 1640 years substantially longer than suggested by previous estimates derived from laminated lake sediments and glacial varves but agreeing with the radiocarbon calibration data obtained for barbados corals the calendar ages of the boundaries of the yd 12 920 and 11 280 cal bp are tentatively set

irregular glacial interstadials recorded in a new greenland ice core the greenland ice sheet offers the most favourable conditions in the northern hemisphere for obtaining high resolution continuous time series of climate related parameters profiles of 18o 16o ratio along three previous deep greenland ice cores1 3 seemed to reveal irregular but well defined episodes of relatively mild climate conditions interstadials during the mid and late parts of the last glaciation but there has been some doubt as to whether the shifts in oxygen isotope ratio were genuine representations of changes in climate rather than artefacts due to disturbed stratification here we present results from a new deep ice core drilled at the summit of the greenland ice sheet where the depositional environ ment and the flow pattern of the ice are close to ideal for core recovery and analysis the results reproduce the previous findings to such a degree that the existence of the interstadial episodes can no longer be in doubt according to a preliminary timescale based on stratigraphic studies the interstadials lasted from 500 to 2 000 years and their irregular occurrence suggests complexity in the behaviour of the north atlantic ocean circulation

late and post glacial evolution of lake steisslingen i abstract piston cores from lake steisslingen a small hard water lake situated 20 km west of lake constance and mainly supplied by submerged springs reveal a record of the environmental history going back to 15 600 cal yr bp from the bolling to ca 9800 cal yr bp the sediments are partly seasonally laminated from then on up to the middle ages the lamination is mostly undisturbed providing a high resolution time scale by varve counting a detailed pollen profile and 13 ams 14c analyses all investigated sediment sections show evidence of exceptionally high sulphate concentrations in the lake water which lead to the fixation of all reactive iron as pyrite the high sulphur content can only be attributed to s rich water supplied by the submerged springs thus indicating the miocene obere meeres molasse as the dominant aquifer since soil erosion is strongly reduced due to increased forest density in the preboreal boreal the submerged springs are the main nutrient source for the lake mixing or stable stratification of the waterbody mostly depends on nutrient availability and bioproductivity in the epilimnion the controlling external factors are wind and changes in water level and or temperature at the end of the younger dryas and during the preboreal low water levels and precipitation rates are assumed the water column mixing was regular bioproductivity high and high degradation activity of organic matter led to a redissolution of calcite the hydrological separation of a northern shallow lake seeried probably fell into the period of this low lake level around 10 450 10 300 cal yr bp the lake level rose but never again reached the former level between 10 000 and 7200 cal yr bp non glacial varves are even found in shallower parts of the lake indicating a stable anoxic monimolimnion with a rising chemocline bioproductivity was low wind protection provided by the now dense forestation and favourable climatic conditions e g high summer temperatures and low winter temperatures seem to be the responsible factors fluctuating human impact is identified from about 7400 cal yr bp until permanent settlement by the alemanni about 1500 cal yr bp strong human influence is observed from 2000 cal yr bp onwards when agricultural activity and clearing of the shoreline vegetation by man caused high soil erosion rates and thus eutrophication at about 800 cal yr bp the recent hydrological conditions were established by implementing an artificial drain thus lowering the lake level

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

evidence for general instability of past climate from a 250 kyr ice core record recent results1 2 from two ice cores drilled in central greenland have revealed large abrupt climate changes of at least regional extent during the late stages of the last glaciation suggesting that climate in the north atlantic region is able to reorganize itself rapidly perhaps even within a few decades here we present a detailed stable isotope record for the full length of the greenland ice core project summit ice core extending over the past 250 kyr according to a calculated timescale we find that climate instability was not confined to the last glaciation but appears also to have been marked during the last interglacial as explored more fully in a companion paper3 and during the previous saale holstein glacial cycle this is in contrast with the extreme stability of the holocene suggesting that recent climate stability may be the exception rather than the rule the last interglacial seems to have lasted longer than is implied by the deep sea specmap record4 in agreement with other land based observations5 6 we suggest that climate instability in the early part of the last interglacial may have delayed the melting of the saalean ice sheets in america and eurasia perhaps accounting for this discrepancy

a 15 000 year stable isotope record from sediments of lake steisslingen southwest germany abstract stable isotope records for carbon and oxygen in bulk carbonates carbon in bulk organic matter and for total and chromium reducible sulfur in a lacustrine sediment core from lake steisslingen southwest germany show several distinct and abrupt shifts during the last 15 000 years variations in the isotopic composition of authigenic carbonates indicate two major phases in the lake history in the pre holocene the hydrological budget of the lake was apparently stable variations of 18 o values of authigenic carbonates were therefore dominantly controlled by temperature changes a decrease in the 18 o carb values of about 2 at the allerod younger dryas transition is interpreted as a drop in mean annual air temperatures of approximately 5 c an abrupt temperature increase of a similar magnitude is inferred at the younger dryas preboreal boundary throughout most of the holocene the isotopic composition of authigenic carbonates was influenced by marked changes in the hydrological budget of the lake a major positive excursion in the 13 c carb and 18 o carb values at the beginning of the atlantic and a smaller one in the preboreal were related to evaporation effects which indicate that dry climatic conditions must have prevailed at that time a simultaneous increase in 13 c values of bulk organic matter at the beginning of the atlantic suggests a high level of productivity in the lake as a consequence aqueous sulfate became limited as indicated by variations in the 34 s values of total and chromium reducible sedimentary sulfur therefore we conclude that the beginning of the atlantic was characterized not only by dry but also by warm climatic conditions which triggered a higher productivity in the lake in the subatlantic sediments large variations in carbon oxygen and sulfur isotope ratios were observed as a result of human activities causing considerable perturbations in the biogeochemical element cycling of lake steisslingen results obtained by the study of the continuous 15 ka record of lake steisslingen document clearly that isotopic proxy data from lacustrine sediments can provide useful information on environmental and climatic changes of local regional and in the case of the younger dryas event of even hemispherical significance

isotopic composition and speciation of sulfur in the miocene monterey formation reevaluation of sulfur reactions during early diagenesis in marine environments the timing and pathways of early diagenetic sulfur transfer from dissolved species in pore waters to solid inorganic and organic compounds in sediments have been studied in the miocene monterey formation santa maria basin onshore california correlation between concentrations of total organic carbon toc and total sulfur ts in addition to concentrations of titanium aluminum total iron and reactive iron have been used to infer organic matter reactivity redox conditions and relative rates of clastic and biogenic input for each lithofacies isotopic compositions of six sulfur species acid volatile disulfide kerogen bitumen sulfate and elemental have provided information regarding relative timing of sulfur incorporation sulfate diffusivity in the upper centimeters of the sediments and the sources of sulfur for individual species isotopically the disulfide species expresses the greatest fractionation relative to estimated values of miocene seawater sulfate 22 cdt on average disulfide is depleted in 34s by 10 4 relative to kerogen and by 9 9 relative to acid volatile sulfide the 34s of bitumen shows no systematic change relative to 34skeregon suggesting the presence of migrated bitumen isotopic similarity of sulfate and elemental sulfur to sulfides and bitumen indicates that sulfate and elemental sulfur are chemical and or biological oxidation products derived from sulfides and bitumen consistent ordering of isotopic values for sulfur species disulfide acid volatile sulfide kerogen indicates that pyrite precipitated nearest to the sediment water interface under mildly reducing conditions and with little or no decrease in sulfate concentration relative to seawater enrichment of 34s in acid volatile sulfide and kerogen sulfur resulted from formation of these species at greater depths or in restricted micro environments under more reducing conditions and with low concentrations of porewater sulfate the formation of acid volatile sulfide after pyrite but during early diagenesis is significant because it implies more strongly reducing conditions than are generally recognized in deep water marine sediments

time dependent evolution of rock slopes by a multi modelling approach abstract this paper presents a multi modelling approach that incorporates contributions from morpho evolutionary modelling detailed engineering geological modelling and time dependent stress strain numerical modelling to analyse the rheological evolution of a river valley slope over approximately 10 2 kyr the slope is located in a transient tectonically active landscape in southwestern tyrrhenian calabria italy where gravitational processes drive failures in rock slopes constraints on the valley profile development were provided by a morpho evolutionary model based on the correlation of marine and river strath terraces rock mass classes were identified through geomechanical parameters that were derived from engineering geological surveys and outputs of a multi sensor slope monitoring system the rock mass classes were associated to lithotechnical units to obtain a high resolution engineering geological model along a cross section of the valley time dependent stress strain numerical modelling reproduced the main morpho evolutionary stages of the valley slopes the findings demonstrate that a complex combination of eustatism uplift and mass rock creep mrc deformations can lead to first time failures of rock slopes when unstable conditions are encountered up to the generation of stress controlled shear zones the multi modelling approach enabled us to determine that such complex combinations may have been sufficient for the first time failure of the s giovanni slope at approximately 140 ka mis 7 even without invoking any trigger conversely further reactivations of the landslide must be related to triggers such as earthquakes rainfall and anthropogenic activities this failure involved a portion of the slope where a plasticity zone resulted from mass rock creep that evolved with a maximum strain rate of 40 per thousand years after the formation of a river strath terrace this study demonstrates that the multi modelling approach presented herein is a useful tool for estimating the progressive development of slope failures because it can highlight time dependent continuous deformations as the major processes that drive rocky slopes to failure this type of approach can be devoted to the best selection of risk mitigation strategies with respect to both human life and anthropic infrastructure

age dating and the orbital theory of the ice ages development of a high resolution 0 to 300 000 year chronostratigraphy using the concept of orbital tuning a continuous high resolution deep sea chronostratigraphy has been developed spanning the last 300 000 yr the chronology is developed using a stacked oxygen isotope stratigraphy and four different orbital tuning approaches each of which is based upon a different assumption concerning the response of the orbital signal recorded in the data each approach yields a separate chronology the error measured by the standard deviation about the average of these four results which represents the best chronology has an average magnitude of only 2500 yr this small value indicates that the chronology produced is insensitive to the specific orbital tuning technique used excellent convergence between chronologies developed using each of five different paleoclimatological indicators from a single core is also obtained the resultant chronology is also insensitive to the specific indicator used the error associated with each tuning approach is estimated independently and propagated through to the average result the resulting error estimate is independent of that associated with the degree of convergence and has an average magnitude of 3500 yr in excellent agreement with the 2500 yr estimate transfer of the final chronology to the stacked record leads to an estimated error of 1500 yr thus the final chronology has an average error of 5000 yr