lateglacial climate development in nw romania comparative results from three quantitative pollen based methods abstract this paper provides quantitative reconstructions of the lateglacial changes in four climate parameters from two fine resolution pollen profiles in the gutaiului mountains nw romania climate estimates are based on two modern analogue techniques with and without considering vegetation types and weighted averaging partial least squares regression wa pls giving evidence for several climatic fluctuations during the period from 14 700 to 11 500 cal yr bp the comparative results of the two modern analogue techniques show consistent trends of climate changes that are also coherent at both sites but these results appear to largely disagree compared with climate reconstruction provided by wa pls the modern analogue techniques revealed four intervals with low temperatures prior to 14 700 cal yr bp between 13 950 and 13 800 13 400 and 13 200 and 12 700 and 11 700 cal yr bp the temperature declines were more pronounced for winter than for summer suggesting an intensification of seasonality which together with a drop in precipitation indicates an increase in continentality the younger dryas is the most pronounced cooling phase with winter temperatures 14 16 c colder than modern conditions annual and summer temperatures 2 5 c and 2 c respectively below present ones precipitation was 400 500 mm half that of present during the bolling and allerod summer temperatures were close to modern values 13 to 17 c whereas winter 6 to 12 c and annual temperatures 0 5 to 6 c as well as precipitation were 550 to 700 mm lower indicating more continental conditions compared to the present day climate

cosmic ray labeling of erosion surfaces in situ nuclide production rates and erosion models a number of in situ cosmogenic radionuclides and stable nuclides have been measured in natural exposed rock surfaces with a view to study their in situ production and rock erosion rates 1 the in situ radionuclides can be used for a high resolution tomography of the erosional history of an exposed surface two stable nuclides 3he 21ne and five radionuclides 10be 26al 36cl 14c 39ar having half lives in the range of 300 1 5 106 yr half life are measurable in many rock types a prerequisite for the application of the in situ nuclides for the study of erosional histories of surfaces is a knowledge of their production rates under different irradiation conditions altitude latitude irradiation geometry and shielding relative nuclide production rates can be determined fairly accurately using the extensive available data on cosmic ray neutrons 2 absolute nuclide production rates cannot generally be predicted with any accuracy because of lack of data on excitation functions of nuclides unless some normalization is possible as was done in the case of several cosmic ray produced isotopes in the atmosphere 3 based on a recent natural calibration experiment in which erosion free surfaces exposed to cosmic radiation for 11 000 yrs were sampled the absolute production rates of 10be and 26al in quartz have been accurately estimated for mountain altitudes in sierra nevada 4 the absolute production rates of 10be and 26al in quartz can therefore be estimated fairly accurately for any given latitude and altitude some measurements of 14c in rocks of low erosion rate 5 similarly allow an estimate of its production rate attempts made to measure the in situ production rates of 3he in rocks have not yet led to a convergent production rate in view of the importance of knowing the production rates of isotopes of he ne and ar i present here theoretical estimates of their production rates based on available cross section data i discuss the information that can be extracted from the study of the in situ nuclides in rocks useful parameters characterizing the exposure history of a rock surface are 1 the effective surface exposure age and 2 the time averaged erosion rate the implications of these parameters for single and multiple nuclide studies are discussed in terms of the erosion models considered

paleoglaciation of the tibetan plateau and surrounding mountains based on exposure ages and ela depression estimates the tibetan plateau holds an ample record of past glaciations and there is an extensive set of glacial deposits dated by exposure dating here a compilation is presented of 10be exposure ages from 485 glacial deposits with 1855 individual samples on the tibetan plateau and ela depression estimates for the glacial deposits based on a simple toe to headwall ratio approach to recalculate the tibetan plateau exposure ages 10be production rates from 24 calibration sites across the world are compiled and recalibrated yielding an updated global reference 10be production rate the recalculated exposure ages from the tibetan plateau glacial deposits are then divided into three groups based on exposure age clustering to discriminate good well clustered from poor scattered deglaciation ages a major part of the glacial deposits have exposure ages affected by prior or incomplete exposure complicating exposure age interpretations the well clustered deglaciation ages are primarily from mountain ranges along the margins of the tibetan plateau with a main peak between 10 and 30 ka indicating glacial advances during the global lgm a large number of deglaciation ages older than 30 ka indicates maximum glaciation predating the lgm but the exposure age scatter generally prohibits accurate definition of the glacial chronology the ela depression estimates scatter significantly but the main part is remarkably low average ela depressions of 337 197 m for the lgm and 494 280 m for the pre lgm indicate restricted glacier expansion

chronological and geomorphological investigation of fossil debris covered glaciers in relation to deglaciation processes a case study in the sierra de la demanda northern spain abstract in this study fossil debris covered glaciers are investigated and dated in the sierra de la demanda northern spain they are located in glacial valleys of approximately 1 km in length where several moraines represent distinct phases of the deglaciation period several boulders in the moraines and fossil debris covered glaciers were selected for analysis of 10 be surface exposure dating a minimum age of 17 8 2 2 ka was obtained for the outermost moraine in the san lorenzo cirque and was attributed to the global last glacial maximum lgm or earlier glacial stages based on deglaciation dates determined in other mountain areas of northern spain the youngest moraines were dated to approximately 16 7 1 4 ka and hence correspond to the gs 2a stadial oldest dryas given that the debris covered glaciers fossilize intermediate moraines it was deduced that they developed between the lgm and the oldest dryas coinciding with a period of extensive deglaciation during this deglaciation phase the cirque headwalls likely discharged large quantities of boulders and blocks that covered the residual ice masses the resulting debris covered glaciers evolved slowly because the debris mantle preserved the ice core from rapid ablation and consequently they remained active until the end of the late glacial or the beginning of the holocene for the san lorenzo cirque and the holocene thermal maximum for the mencilla cirque the north facing part of the mencilla cirque ensured longer preservation of the ice core

chronology of the late weichselian glaciation in the bohemian forest in central europe abstract a glacial chronology based on in situ produced 10 be surface exposure dating of moraines in the bohemian forest central europe was established eleven exposure ages obtained for moraine boulders in the prasilske lake and laka lake valleys czech republic were complemented by 10 be ages from kleiner arbersee germany recalculated according to recently calibrated production rates in the northern hemisphere the glacial phases in the bohemian forest occurred during the last glacial maximum around 24 1 2 5 23 6 2 4 21 8 2 0 and 19 5 2 1 ka following phases of local glaciation occurred during the northern hemisphere deglaciation period around 16 ka and 14 ka the last indicated phase may correlate with older dryas the glacial chronology of the bohemian forest is in agreement with local glaciation chronologies in the giant mts krkonose mts and the eastern alps

cold and wet last glacial maximum on mount sandiras sw turkey inferred from cosmogenic dating and glacier modeling abstract in situ cosmogenic 36 cl was measured in boulders from moraines on mount sandiras 37 1 n 28 8 e 2295 m the southwestern most previously glaciated mountain in turkey valleys on the north side of the mountain were filled with 1 5 km long glaciers that terminated at an altitude of 1900 m the glacial activity on mount sandiras correlates with the broadly defined last glacial maximum lgm the maximum glaciation occurred approximately 20 4 1 3 ka 1 1 ka 1000 calendar years ago when glaciers started retreating and the most extensive moraines were deposited the glaciers readvanced and retreated by 19 6 1 6 ka ago and then again by 16 2 0 5 ka using the glacier modeling and the paleoclimate proxies from the eastern mediterranean we estimated that if temperatures during lgm were 8 5 11 5 c lower than modern precipitation was up to 1 9 times more than that of today thus the local lgm climate was cold and wet which is at odds with the conventional view of the lgm as being cold and dry in the region

positive degree day factors for ablation on the greenland ice sheet studied by energy balance modelling ice ablation is related to air temperature by the positive degree day factor variations of the positive degree day factor in west greenland are studied using an energy balance model to simulate ablation under different conditions degree day factors for simulated and measured ice ablation at nordbogletscher and qaman rssup sermia agree well with values around 8 mm d 1 c 1 degree day factors for snow are less than half those for ice energy balance modelling shows that degree day factors vary with summer mean temperature surface albedo and turbulence but there is only evidence of large positive degree day factors at lower temperatures and with low albedo 0 3 the greatest effect of albedo variations 0 3 0 7 is at lower temperatures while variations in turbulence have greater effect at higher temperatures current models may underestimate runoff from the greenland ice sheet by several tenths because they use a degree day factor for melting ice that is too small for the colder parts of the ice sheet i e the upper ablation area and the northerly margin

was the younger dryas triggered by a flood draining of a huge lake into the northern atlantic may have triggered a cold period 12 900 years ago the route taken by the flood waters remains unknown

reply to comment on scaling factors for production rates of in situ produced cosmogenic nuclides a critical reevaluation by darin desilets marek zreda and nathaniel lifton

late pleistocene climate conditions in the north chilean andes drawn from a climate glacier model a climate glacier model was used to reconstruct late glacial climate conditions from two case study glaciers at 18 and 22 s in the arid sub tropical western andes of northern chile the model uses i the geometry of the late glacial maximum glaciation ii modern diurnal and annual cycles amplitudes and lapse rates of the climate iii empirical statistical sublimation melt and accumulation models developed for this area and iv dynamic ice flow through two known cross sections for steady state conditions the model is validated with modern conditions and compares favorably with the glaciological features of today the mass balance model calculates the modern equilibrium line altitude at 18 s as high as 5850 m field data 5800 m whereas no glaciers exist in the fully arid southern area at 22 s despite altitudes above 6000 m and continuous permafrost for late glacial times the model results suggest a substantial increase in tropical summer precipitation ap 840 50 10 mm a 1 for the northern test area 1000 10 30 mm a 1 for the southern test area and a moderate temperature depression t 4 4 0 1 0 2 c at 18 s 3 2 0 1 c at 22 s extratropical frontal winter precipitation june september was 15 of the total annual precipitation a scenario with higher winter precipitation from the westerlies circulation belt does not yield a numerical solution which matches the observed geometry of the glaciers therefore we conclude that an equatorward displacement of the westerlies must be discarded as a possible explanation for the late pleistocene glaciation in the andes of northern chile

an early advance of glaciers on mount akdag sw turkey before the global last glacial maximum insights from cosmogenic nuclides and glacier modeling abstract for the first time in turkey we report an early advance of glaciers before the broadly defined global last glacial maximum lgm forty one moraine boulders from three glacial valleys on mount akdag 36 54 n 29 57 e 3016 m southwest coast of turkey were dated with cosmogenic 36 cl valleys on the north side of the mountain were filled with few km long glaciers that terminated at elevations of about 2000 m above sea level a s l the pre lgm glaciations reached their maximum positions 2150 m a s l by 35 1 2 5 ka ago 1 ka 1000 calendar years the glaciers readvanced during the global lgm and reached their farthest locations 2050 m a s l by around 21 7 1 2 ka ago later glaciers retreated and shortly stabilized during the lateglacial at around 15 1 0 9 ka ago using the glacier modeling and paleoclimate proxies from the eastern mediterranean we estimated that if temperatures during the lgm were 8 11 c colder than modern which is suggested by paleotemperature proxies from the region precipitation was up to two times more than that of today previous estimates on southwest coast of turkey indicate a similar precipitation value while central turkey requires drier conditions implying regional heterogeneity on lgm climates in turkey

climate variability in the spanish pyrenees during the last 30 000 yr revealed by the el portalet sequence abstract palynological sedimentological and stable isotopic analyses of carbonates and organic matter performed on the el portalet sequence 1802 m a s l 42 48 00 n 0 23 52 w reflect the paleoclimatic evolution and vegetation history in the central western spanish pyrenees over the last 30 000 yr and provide a high resolution record for the late glacial period our results confirm previous observations that deglaciation occurred earlier in the pyrenees than in northern european and alpine sites and point to a glacial readvance from 22 500 to 18 000 cal yr bp coinciding with the global last glacial maximum the patterns shown by the new high resolution pollen data from this continental sequence chronologically constrained by 13 ams 14c dates seem to correlate with the rapid climate changes recorded in greenland ice cores during the last glacial interglacial transition abrupt events observed in northern latitudes heinrich events 3 to 1 oldest and older dryas stades intra allerod cold period and 8200 cal yr bp event were also identified for the first time in a lacustrine sequence from the central western pyrenees as cold and arid periods the coherent response of the vegetation and the lake system to abrupt climate changes implies an efficient translation of climate variability from the north atlantic to mid latitudes

accuracy of cosmogenic ages for moraines analyses of all published cosmogenic exposure ages for moraine boulders show an average age range of 38 between the oldest and youngest boulders from each moraine this range conflicts with the common assumption that ages of surface boulders are the same as the age of the landform the wide spread in boulder ages is caused by erosion of the moraine surface and consequent exhumation of fresh boulders a diffusion model of surface degradation explains the age range and shows that a randomly sampled small set of boulders n 3 7 will always yield a lower age limit for the moraine the model indicates that for identical dating accuracy six to seven boulders are needed from old and tall moraines 40 000 100 000 yr 50 100 m initial height but only one to four boulders from small moraines 20 000 100 000 yr 10 20 m by following these guidelines the oldest obtained boulder age will be 90 of the moraine age 95 probability this result is only weakly sensitive to a broad range of soil erosion rates our analysis of published boulder ages indicates that 3 of all moraine boulders have prior exposure and 85 of these boulders predate the dated moraine

exposure age chronology of the last glaciation in the eastern pyrenees abstract we present a chronology of ice recession in the eastern pyrenees based on in situ produced 10be data obtained from the tet paleoglacier complex the sampling strategy is based on the relative chronology provided by a detailed geomorphological map of glacial landforms results indicate that the last maximum ice advance occurred late i e during marine isotope stage 2 compared to the chronology currently established for the rest of the pyrenees despite debatable evidence for a glacial readvance during the oldest dryas stade ice cap melt out was rapid residual cirque glaciers having disappeared by the allerod interstade this is consistent both with north atlantic excursions established by the greenland ice cores and paleoenvironmental data for the region the rapid response of the east pyrenean ice cap to temperature variations is primarily linked to its small size compared to larger pyrenean ice fields to the dry mediterranean climate and to topography related nonlinearities in which a small vertical rise in equilibrium line altitude generates a large change in ice mass possible sources of age uncertainty are discussed in the context of sampling design for single nuclide 10be dating of landform sequences in formerly glaciated landscapes

the influence of aspect and altitude on the size shape and spatial distribution of glacial cirques in the high tatras slovakia poland the shape of glacial cirques is generally considered to result from the combined actions of climate topography and geology the goal of this article was to determine the dependence of cirque morphology on mesoclimatic conditions defined by altitude and aspect in the highest part of the carpathians the high tatras the morphology of each of 116 analyzed cirques was described using a set of 12 morphometric characteristics the relationships between the obtained data were evaluated using simple and multivariate statistical methods the results indicate that cirques in the high tatras are scale specific landforms with allometric development their occurrence increases with altitude but their size decreases the shape of the cirques is determined by altitude only to a small extent with the exception of an increase in the degree of incision with altitude the spatial distribution of cirques is negatively influenced by incoming solar radiation and positively influenced by moisture sources which came mainly from the nw to n during the cold phases of the pleistocene for this reason north facing cirques have proportionally stronger representation and are more incised with steep slopes thus cirques have proportionally stronger representation on the northern slopes and represent more developed glacial erosion landforms than those on the southern slopes although some relationships were detected between cirque morphology and mesoclimatic factors such as altitude and aspect a general discriminant analysis showed that these environmental factors did not explain variations in cirque morphology with sufficient cogency

late quaternary sackungen in the highest mountains of the carpathians sackungen represents a common mode of deep seated rock slope failures in alpine landscapes but proof of their temporal and causal relationship to extrinsic factors such as climatic changes glacier retreat or seismic activity remains elusive based on the terrestrial cosmogenic nuclide tcn dating of 18 sackung scarps supported by one radiocarbon dated scarp we reconstructed the post glacial chronology of sackungen in the tatra mts central europe slovakia and poland the highest part of the carpathians the obtained ages 15 7 4 3 ka indicate that sackungen post date the regional lgm and some of them originated soon after the glacier withdrawal from adjacent valleys furthermore systematic decrease of scarp ages with their increasing altitude suggests a direct link between sackung origin and post lgm glacier thinning however substantial lag 5 ka of some sackungen in respect to glacier retreat implies complex relationships between sackung onset and deglaciation where retreat of glaciers acted predominantly as a preparatory not a triggering factor during the genesis of these slope deformations they originated either as a consequence of stress relaxation within the rock mass lasting several ka or alternatively could be triggered by climatic processes or seismicity indeed a significant part of sackung activity took place during predominantly warmer and more humid periods with some dates coinciding with the belling allerod chronozone but especially with the onset of the holocene and the holocene climatic optimum earthquake triggering is less probable as the tatra mts lack significant modern and historic seismic activity and there is no geomorphic evidence of fault offsets on the late quaternary landforms in concert with other recent studies we propose that large rock slope failures in high mountains seldom react immediately to glacier withdrawal but could display temporal delay lasting up to several millennia c 2017 elsevier ltd all rights reserved

pleistocene ice caps on the coastal mountains of the adriatic sea ice caps once covered large areas of mount orjen 1894 m on the adriatic coast of montenegro bosnia herzegovina croatia the largest ice cap covered an area of c 165 km2 and reached a maximum ice thickness of c 450 m in some areas reaching down to 500 m above modern sea level u series dating of secondary carbonates within moraines indicates that the most extensive glaciation occurred during the middle pleistocene correlating with a major phase of glaciation in greece to the south during mis 12 c 480 430 ka later less extensive glaciations are also recorded in the cirques and valleys and correlate with glaciations during mis 6 190 130 ka and mis 5d 2 110 11 7 ka each phase of glaciation would have required large amounts of snow accumulation under modern precipitation values which at c 5000 mm are some of the highest in europe mean annual temperatures would need to be only c 5 6 c lower in order to form similar sized glaciers today a mean annual temperature depression of 12 13 c would still require 1000 mm of snow accumulation water equivalent to balance ablation suggesting sustained moisture supply during pleistocene cold stages such sustained precipitation supply during pleistocene cold stages is likely to have been facilitated by major temperature contrasts between the european landmass and the mediterranean sea which are likely to have sustained lee side vortices to the south of the alps in the gulf of genoa and adriatic sea forming weak moisture bearing depressions which tracked across the eastern adriatic coastal mountains large ice caps on the dinaric alps would have blocked the inland penetration of these depressions resulting in much drier conditions in the balkan interior creating favourable conditions for the deposition of thick accumulations of loess the last glaciers on orjen formed during the younger dryas 12 9 11 7 ka and confirm the influence of north atlantic ocean circulation on pleistocene climate change in this part of the mediterranean

10be exposure age chronology of the last glaciation in the krkonose mountains central europe abstract a new chronology of the last glaciation is established for the krkonose giant mountains central europe based on in situ produced 10be in moraine boulders exposure ages and schmidt hammer rebound values obtained for terminal moraines on the northern and southern flank of the mountains suggest that the oldest preserved moraines represent early phases of the last glacial maximum lgm large moraines at the outlet of the snowy cirques niezne kotly and in the middle part of the upa ob i d l trough were deposited around 21 ka while a series of smaller moraines above the lgm deposits represent readvances that occurred no later than 18 1 0 6 ka 15 7 0 5 ka 13 5 0 5 ka and 12 9 0 7 ka an exposure age of 13 8 0 4 ka obtained for protalus ramparts at the foot of the upska jama cirque headwall indicates that glaciers advanced only in north to east facing cirques during the lateglacial the last glacier fluctuation was synchronous with the younger dryas cold event the timing of local glacier advances during the last glacial episode correlates with the late weichselian glacier phases in the alps and in the bavarian bohemian forest

last glacial maximum temperatures over the north atlantic europe and western siberia a comparison between pmip models margo sea surface temperatures and pollen based reconstructions abstract evaluating the ability of models to simulate climates different from the modern one is important for climate prediction here we present a first comparison between results from simulations of the last glacial maximum climate and continental and surface ocean reconstructions for the north atlantic europe and western siberia the simulations include prescribed sea surface temperature sst and slab ocean atmospheric general circulation model runs performed within the pmip1 project and atmosphere ocean fully coupled runs performed after pmip1 and within the pmip2 project the surface ocean reconstructions are from the margo project continental reconstructions are based on pollen data over the north atlantic most models simulate the strengthening of the sst meridional gradient suggested by the reconstructions but most do not reproduce the lgm control sst anomaly at the right location nor with the right amplitude over western siberia the model results are much improved when a new ice sheet reconstruction ice 5g is used to force the models the main discrepancy remains for western europe winter temperatures for which lgm control anomalies are significantly underestimated by all models all models indicate that this region during the lgm experienced significantly higher interannual variability in coldest month temperatures compared to the control runs this increased variability could have conspired to bias the apparently extremely cold pollen based temperature reconstructions

deglaciation chronology and paleoclimate of the pieciu stawow polskich roztoki valley high tatra mountains western carpathians since the last glacial maximum inferred from 36cl exposure dating and glacier climate modelling abstract exposure dating of abraded bedrock surfaces below glacial trimlines in the pieciu stawow polskich roztoki valley using cosmogenic 36 cl has been applied to determine the deglaciation chronology in the study area nineteen rock samples yielded ages between 21 5 and 9 5 ka the spatial distribution of ages provides evidence of progressive downwasting of glaciers within the study area dates of exposure indicate that the onset of ice volume decrease occurred no later than 21 5 ka this provides evidence that the local maximum glaciation occurred in accordance with the global last glacial maximum lgm the first period of deglaciation in the study area was completed around 18 ka further significant loss of ice volume is confirmed between 15 and 13 ka the spatial distribution of chronological data within the pieciu stawow polskich valley indicates post lgm readvances of glaciers around 17 ka and 12 ka using the glacier modelling and paleoclimate proxies from the study area the early late glacial glacier had been stable with a 9 10 c decrease in temperature and 30 50 lower precipitation in relation to modern conditions the subsequent advance took place with temperatures 6 7 c lower and 10 30 less precipitation the timing of the readvances is nearly synchronous with late glacial advances in the european alps southern carpathians and anatolian peninsula this suggests synchronicity of major climatic fluctuations across central europe and the northern margin of the mediterranean basin

size specific steady state accumulation area ratio an improvement for equilibrium line estimation of small palaeoglaciers abstract characteristic distribution of the steady state accumulation area ratio aar0 of valley and corrie glaciers was investigated in a global dataset comprised of 46 glaciers there is a positive relationship between aar0 and glacier area with smaller glaciers having lower values of aar0 compared with larger glaciers the relationship between glacier area s and steady state aar of studied glaciers can be optimally described by a logarithmic regression equation this relationship is thought to be a globally valid approximation if the size of the glacier is not smaller than 10 1 km2 in the case of palaeoglaciers an aar0 value of 0 44 0 07 is best applied on glaciers with areas in the range 0 1 1 km2 0 54 0 07 for glaciers covering areas between 1 and 4 km2 and 0 64 0 04 for glaciers larger than 4 km2 this assumes insignificant debris cover for the investigated palaeoglaciers the proposed size specific aar0 values take into account the geometric hypsometric properties of palaeo glaciers the results have major importance for palaeoglaciological reconstructions in many regions of former marginal niche glaciation characterized by small former glaciers

permafrost or seasonal frost a review of paleoclimate proxies of the last glacial cycle in the east central european lowlands abstract our critical revision of the sedimentological characteristics and genetic interpretation of relict periglacial soil deformation features cryoturbations and sand wedges suggests that the continuous permafrost zone did not necessarily reached the lowland areas of the pannonian basin as suggested by previous studies the discontinuous permafrost zone most probably penetrated the north western part of the study area for a certain period but most of the lowlands might have been affected only by sporadic isolated permafrost and or deep seasonal frost the re evaluated climate conditions implied by the periglacial soil structures and other proxies for a periglacial environment of the area do not constrain such a narrow zone of extremely low mean annual air temperature maat and mean annual precipitation map the compilation of the climate thresholds suggested by the observed and revised interpretation cryoturbation features and thermal contraction cracks with other paleoclimate proxies converge on 0 2 c maat and 300 490 mm map on the lowland areas of the pannonian basin during the coldest phase of the last glacial these values indicate a temperature drop of 10 2 c and a precipitation decrease of 30 50 relative to modern conditions

landscape evolution degrades the geologic signature of past glaciations glaciers on land leave behind characteristic landforms and bedrock topography the spatial extent of this signature and dating of the erosional and depositional features has led to a good understanding of temporal and spatial shifts of past glaciers and climate at best the landscape contains considerable information on past glacial processes in the form of moraines and other depositional landforms however evidence suggests that all unconsolidated landforms degrade manifested in the general degradation and smoothing of the topography over time to determine the relative amount and pattern of degradation on glacial moraines we use a well documented moraine degradation model that uses both local slope and a proportionality constant to determine the diamicton transport rate this formulation results in diffusion type topographic smearing and smoothing of the initially angular topographic features more specifically diamicton is eroded at the crest of a moraine transported downhill and deposited on the gentler lower flank collectively this produces moraine cross profiles that closely resemble observations in the field by assuming an initial constant boulder frequency per unit volume of the diamicton the model tracks the surface lowering and the related exhumation of boulders to the moraine surface this produces a tightly constrained set of testable predictions 1 modelled moraine cross profile 2 modelled spatial pattern of surface boulders no boulders on the lower flank and 3 relative frequency of surface boulders smallest frequency of surface boulders at the inflection point highest frequency at the crest these characteristics were measured in the field of alpine tropical and antarctic moraines the correspondence between model predictions and field data is remarkably good and strongly supports our understanding of the time dependent evolution of glacial landscapes these results highlight the evolving nature of glacial landforms and indicate the complete removal of original moraine surfaces and postglacial emergence of spatial pattern in boulder frequency

geomorphological evidence and 10be exposure ages for the last glacial maximum and deglaciation of the velka and mala studena dolina valleys in the high tatra mountains central europe abstract 10be exposure age chronology of the last glaciation was established in a key area at the southern slopes of the high tatra mts western carpathians in situ produced 10be in moraine boulders glacially transformed bedrock surfaces and rockfall accumulations constrains the timing of the last glacial maximum lgm glacier expansion and provides chronological evidence for the post lgm decay of one of the largest paleoglaciers in the range the uncertainty weighted mean age of 22 0 0 8 ka obtained for the terminal moraine in the forefield of the velka studena dolina valley indicates that the oldest moraine was deposited close to the global lgm this finding confirms that well preserved moraines in the range were formed during the last glacial cycle and that glaciation on the southern flank of the range was more extensive than earlier in the last glacial cycle the maximum glacier extent correlates with late wurmian weichselian glacier phases in the alps the bavarian bohemian forest and the krkonose mts but probably postdates the period of maximum glaciation in the southern carpathians re advance moraines at the mouth of the velka studena dolina valley and in the middle part of the mala studena dolina valley were deposited no later than around 20 5 ka and 15 5 ka respectively the timing of these advances is broadly synchronous within the high tatra mts as well as with glacier advances in the alps bavarian bohemian forest and krkonose mts 10be exposure ages obtained from glacially transformed bedrock surfaces range between 20 5 1 7 ka and 10 7 0 3 ka constraining the onset and the final phase of the deglaciation surface exposure dating of four rockfall accumulations produced uncertainty weighted mean ages of 20 2 1 2 ka 17 0 0 7 ka 16 5 0 4 ka and 15 6 0 7 ka these ages indicate that activation of rock slope failures occurred under paraglacial conditions within a few centuries up to 1400 years after the formation of re advance moraines

revised deglaciation history of the pietrele stânisoara glacial complex retezat mts southern carpathians romania abstract although geomorphological evidences of quaternary glaciations of the southern carpathians were extensively studied and discussed the limited number of chronological studies resulted in poor and controversial knowledge on the age of glaciations and deglaciation of the area we use new and recalculated in situ produced 10be surface exposure ages of glacial landforms to shed light on the age of the maximum glacial extent and the glacier oscillations during the last deglaciation process on the northern side of the retezat mountains according to our data the maximum ice extent documented by preserved moraines occurred around 21 0 1 5 0 8 ka coincident with the global last glacial maximum lgm the deglaciation process during the lateglacial was characterized by two glacial advances at 18 6 0 8 0 9 and 16 3 0 6 0 6 ka inferred stabilization date of the penultimate glacial stage at 15 2 0 8 0 7 ka was closely followed by the abrupt warming at the onset of the bolling allerod documented by a local chironomid based temperature reconstruction the last small glacier advance was dated to 13 5 0 4 0 5 ka these recessional readvance phases agree with other european glacial chronologies

sensitivity of mass balance of five swiss glaciers to temperature changes assessed by tuning a degree day model a degree day model is used to assess the sensitivity of the mass balance of five swiss glaciers to temperature changes the model uses temperature data extrapolated from nearby climate stations and is tuned by varying precipitation to make the model fit the observed distribution of mass balance with altitude once the model is tuned the effect of temperature change is simulated by recalculating the mass balance with the same parameters as before but with a temperature increase of 1 c throughout the year the largest mass balance changes involving increased ablation of 1 m w e a 1 c 1 occur at the snout with a progressively smaller increase with altitude the area averaged sensitivities for the five glaciers are 0 7 to 0 9 m w e a 1 c 1 if annual precipitation also increased by 20 it would partly offset the effect of the 1 c higher temperatures but could not compensate for it

10 be exposure age chronology of the last glaciation of the rohacska valley in the western tatra mountains central europe abstract 10 be exposure ages from moraines and bedrock sites in the rohacska valley provide chronology of the last glaciation in the largest valley of the western tatra mts the western carpathians the minimum apparent exposure age of 19 4 2 1 ka obtained for the oldest sampled boulder and the mean age of 18 0 0 8 ka calculated for the terminal moraine indicate that the oldest preserved moraine was probably deposited at the time of the global last glacial maximum lgm the age of this moraine coincides with the termination of the maximum glacier expansion in other central european ranges including the adjacent high tatra mts and the alps the equilibrium line altitude ela of the lgm glacier in the rohacska valley estimated at 1400 1410 m a s l was 50 80 m lower than in the eastern part of the range indicating a positive ela gradient from west to east among the north facing glaciers in the tatra mts lateglacial glacier expansion occurred no later than 13 4 0 5 ka and 11 9 0 5 ka as indicated by the mean exposure ages calculated for re advance moraines this timing is consistent with the exposure age chronology of the last lateglacial re advance in the high tatra mts alps and lower mountain ranges in central europe the ela in the rohacska valley estimated at 1690 1770 m a s l in this period was located 130 300 m lower than in the north facing valleys in the high tatra mts 10 be exposure ages obtained for a rock glacier constrains the timing of this landform stabilization in the salatinska valley and provides the first chronological evidence for the lateglacial activity of rock glaciers in the carpathians

regional synthesis of mediterranean atmospheric circulation during the last glacial maximum atmospheric circulation leaves few direct traces in the geological record making reconstructions of this crucial element of the climate system inherently difficult we produced a regional mediterranean synthesis of paleo proxy data from the sea surface to alpine altitudes this provides a detailed observational context for change in the three dimensional structure of atmospheric circulation between the last glacial maximum lgm 23 000 to 19 000 years ago and the present the synthesis reveals evidence for frequent cold polar air incursions topographically channeled into the northwestern mediterranean anomalously steep vertical temperature gradients in the central mediterranean imply local convective precipitation we find the lgm patterns to be analogous though amplified to previously reconstructed phases of enhanced meridional winter circulation during the maunder minimum the little ice age

maximum extent of late pleistocene glaciers and last deglaciation of la cerdanya mountains southeastern pyrenees abstract this paper examines glacial evolution in the la pera and malniu cirques and aranser la llosa and duran valleys in the cerdanya massifs on the south facing slopes of the eastern pyrenees a geomorphologic analysis and dating of moraine boulders glacially polished bedrock and rock glacier blocks were carried out by means of cosmogenic 36cl surface exposure dating the maximum ice advance was contemporary with the last glacial maximum at 23 ka ago and it was of greater or only slightly lesser magnitude than for previous quaternary advances the termini of glaciers remained close to maximum positions with minor advances and retreats until 18 17 ka when the glacial tongues disappeared from the valleys depending on the previous topography these glaciers left behind a single polygenic moraine in the case of confined valleys or multiple moraines next to each other in the case of flat more open areas a final glacial advance is detected during the oldest dryas close to the cirque headwalls and the glaciers finally disappeared during the bolling interstadial the glaciers were then replaced by rock glaciers whose front immediately became inactive although their activity continued near their source area until the early holocene

chronology of the last glacial cycle in the european alps chronological data for glacier advances in the european alps between the last interglacial eemian and the holocene are summarised 115 to 11 ka during this time glaciers were most extensive extending tens of kilometres out onto the forelands between 30 and 18 ka that is synchronous with the global ice volume maximum of marine isotope stage mis 2 evidence for ice expanding to just past the mountain front for an earlier major glacier advance comes from swiss sites where advances have been luminescence dated to mis 5d 100 ka and mis 4 70 ka up to now no such evidence has been found in the eastern alps by 18 ka more than 80 of the late wurmian ice volume had gone subsequently glaciers readvanced reaching into the upper reaches of the main valleys during the lateglacial gschnitz stadial which likely occurred around 17 ka with final moraine stabilisation no later than 15 4 ka the link of the egesen stadial with the younger dryas climate deterioration is supported by exposure ages from four sites as well as minimum limiting radiocarbon dates from bogs within former glacier tongue areas key questions on the spatial and temporal variability of ice extents throughout the last glacial cycle have yet to be answered copyright 2008 john wiley sons ltd

expression of the younger dryas cold event in the carpathian mountains ukraine past glacial activity in the ukrainian carpathian mountains is characterized by cirques glacial valleys and moraine ridges at altitudes between 1350 and 1850 m a s l although the geomorphology of this area was extensively studied the deposition time of these glacial forms and specifically the moraines was never determined we surveyed and mapped the geomorphology of the pozhezhevs ka glacial valley which is part of the charnogora ridge we used surface exposure dating and developed a data base of this area using remote sensing and geographic information system to understand the timing and nature of glacial event in the eastern carpathian mountains well developed continuous lateral frontal moraines cross the valley floor at 1400 m a s l ten sandstone boulders were sampled from one of these to determine the deposition time of the moraine samples were prepared at the glasgow university cosmogenic nuclide laboratory and analyzed at the suerc ams laboratory surface exposure ages were calculated using the cronus earth online 10be exposure age calculator our exposure ages for nine samples ukr 2 to ukr 10 range from 11 0 0 4 10be ka to 14 5 0 5 10be ka one sample ukr 1 produced no current and thus no exposure age is available the mean deposition time for the moraine ranges from 12 4 0 3 to 12 9 0 3 10be ka depending on choice of surface erosion and snow cover these results provide the first direct indication using surface exposure dating of a possible glacier response in the ukrainian carpathian mountains to a cold event contemporary with the younger dryas yd together with exposure ages from other mountain ranges across europe the new data provide direct chronological evidence for a widespread expression of the yd cold event outside the main ice margin limits left by the former scandinavian ice sheet

late pleistocene climate of poland in the mid european context abstract proxy data from pollen and mollusc indicator species periglacial phenomena changes in geometry of mountain palaeoglaciers and based on selected lithological and geomorphological features enabled reconstruction of the late pleistocene climate characteristics in poland and adjacent areas climate during the eemian was generally stable but with a distinct west east gradient in summer strong influence of the atlantic air masses moving to the east resulted in the annual precipitation over 600 mm climate instability in the late eemian as well as during stadials and interstadials of the early weichselian was expressed by progressive cooling and increasing temperature difference between winters and summers reflecting stronger continentalism towards the west accompanied by decreased precipitation periglacial frost crackings and polygonal patterns indicated occurrence of permafrost in poland already at about 49 ka bp and its occurrence until the termination of the last glaciation these periglacial structures have developed at mean annual temperatures from 9 to 4 c with winter extremes up to about 25 c mean summer temperature reached likely around 10 c as suggested by palaeobotanic record palaeoglaciological studies of mountain glaciers across europe allowed inferring their activity and sensitivity to climatic fluctuations during the late weichselian the weichselian of central europe was controlled mostly by the southerly and easterly circulation dominated by climate cyclones and anticyclones respectively an inflow of air masses from the west was significantly limited and concentrated mainly within the so called periglacial corridor between the scandinavian ice sheet and the alps such circulation pattern determined serious reduction of precipitation during the last glacial maximum that reached 60 in relation to modern conditions the following late pleistocene cold phases oldest and younger dryas were slightly warmer and wetter with increasing contribution of the westerlies that were strongly dependent on progressing shrinkage of the northern hemisphere ice sheets

late pleistocene glacial chronology of the pietrele valley retezat mountains southern carpathians constrained by 10be exposure ages and pedological investigations abstract the southern carpathians are located in the transition zone between mediterranean and continental climates and constituted the major areas of ice accumulation in the carpathians during pleistocene glaciations an absolute glacial chronology had not yet been established in this study we constrain the glacial history of the pietrele valley in the retezat mountains located in the southern carpathians and find that the timing of the late wurmian glacial advance is asynchronous to global climate records likely reflecting changes in moisture availability in the area the former ice extent of two major glacial advances m1 or lolaia glacial advance and m2 or capra judele glacial advance in the valley was reconstructed based on mapping and surveying of glacial features field relations and different pedological weathering indicators of till imply that the m1 glacial advance occurred well before the global last glacial maximum lgm its deposition during the penultimate glaciation is unlikely no boulders suitable for exposure dating were found on m1 moraines seventeen exposure ages show that the moraines of the maximum late wurmian m2 glacial advance were abandoned around 16 1 1 6 ka another late glacial advance m3 or stevia advance occurred during the younger dryas chron as constrained by two exposure ages we suggest that the glacial advance that occurred during the time of the global lgm was less extensive than the m2 glacial advance and the deposits were overrun by the lateglacial m2 glacier as we found no field evidence of glacial deposits between the m1 and the m2 moraines we explain this obvious asynchronity of the local late wurmian ice extent with that of global records of ice accumulation with increased aridity in the carpathians during the global lgm due to a lower sea level the reconstructed late pleistocene equilibrium line altitude ela shows a distinct increase in the trend from the alps and the bavarian forest to the carpathians in comparison to the modern ela this finding supports the high aridity in the study area during the late pleistocene two distinct lateglacial moraines were deposited during times of reported colder and wetter climatic conditions around the north atlantic heinrich events h0 and h1

paleo climate of the central european uplands during the last glacial maximum based on glacier mass balance modeling during the last glacial maximum lgm glaciers existed in scattered mountainous locations in central europe between the major ice masses of fennoscandia and the alps a positive degree day glacier mass balance model is used to constrain paleo climate conditions associated with reconstructed lgm glacier extents of four central european upland regions the vosges mountains the black forest the bavarian forest and the giant mountains with reduced precipitation 25 75 reflecting a drier lgm climate the modeling yields temperature depressions of 8 15 c to reproduce past glaciers more severe cooling is required in the west than in the east indicating a strong west east temperature anomaly gradient

high resolution simulations of the last glacial maximum climate over europe a solution to discrepancies with continental palaeoclimatic reconstructions the analyses of low resolution models simulations of the last glacial maximum lgm 21 kyr bp climate have revealed a large discrepancy between all the models and pollen based palaeoclimatic reconstructions in general the models are too warm relative to the observations especially in winter where the difference is of the order of 10 c over western europe one of the causes of this discrepancy may be related to the low spatial resolution of these models to assess the impact of using high resolution models on simulated climate sensitivity we use three approaches to obtain high resolution climate simulations over europe first an atmospheric general circulation model agcm with a stretched grid over europe second a homogeneous t106 agcm high resolution everywhere on the globe and last a limited area model lam nested in a low resolution agcm with all three methods we have performed simulations of the european climate for present and lgm conditions according to the experimental design recommended by the palaeoclimate modeling intercomparison project pmip model results have been compared with updated pollen based palaeoclimatic indicators for temperature and precipitation that were initially developed in pmip for each model a low resolution global run was also performed as expected the low resolution simulations underestimate the large cooling indicated by pollen data especially in winter despite revised slightly warmer reconstructions of the temperatures of the coldest month and show results in the range of those obtained in pmip with similar models the two high resolution agcms do not improve the temperature field and cannot account for the discrepancy between model results and data especially in winter however they are able to reproduce trends in precipitation more closely than their low resolution counterparts do but the simulated climates are still not as arid as depicted by the data conversely the lam temperature results compare well with climate reconstructions in winter but the simulated hydrological cycle is not consistent with the data finally these results are discussed in regard of other possible causes for discrepancies between models and palaeoclimatic reconstructions for the lgm european climate

latest pleistocene glacier advances and post younger dryas rock glacier stabilization in the mt krivaň group high tatra mountains slovakia abstract the timing of glacier disappearance and rock glacier stabilization in the highest massifs of the carpathians is still poorly documented in this paper we establish the extent and chronology of the final stages of glaciation and timing of stabilization of the uppermost rock glaciers in the tatra mountains which are the highest 2654 m a s l northernmost n 49 12 and coldest range in the carpathians on the base of morphostratigraphic principles schmidt hammer tests and glacier equilibrium line altitude ela estimation we assigned moraines and rock glaciers in the mt kriva massif sw part of high tatras to a threefold stratigraphic sequence with glacial stages advances from older to younger popradske pleso pp sucha va ecka i sv i and sucha va ecka ii sv ii landforms attributed to two younger advances sv i and sv ii were sampled for the purpose of cosmogenic 10be surface exposure dating our data show that pp and sv i glacial advances occurred during the oldest dryas climatic downturn the younger advance sv i occurred just before the bolling allerod b a warming at 14 9 0 4 ka at this time small glaciers occupied lower glacial cirques in the study area the youngest sv ii advance was characterized by rock glaciers and small debris covered glaciers confined to the highest cirques the mean exposure age of four relict rock glaciers of this stage is 11 1 0 9 ka but individual rock glacier mean ages spanned between 11 8 and 10 4 ka our research results show that the youngest moraines and rock glaciers in the tatra mountains were formed during the younger dryas yd but the final permafrost melting and rock glacier stabilization period was delayed until the early holocene but no later than 10 4 ka in high elevation cirque bottoms up to 2120 m a s l the yd glaciers and rock glaciers readvanced across land which was ice free as early as 14 8 14 2 ka thus it is likely that during the b a interphase glaciers completely disappeared in the tatra mountains the yd was the last period of glacial periglacial activity in the massif as we investigated one of the highest situated rock glaciers in the tatras up to 2220 m a s l we conclude that all rock glaciers in this massif are relict landforms which developed in response to severe lateglacial climate conditions the lateglacial climate of the tatra mountains is discussed herein on the basis of glacier equilibrium line altitude ela estimation and the vertical distribution of rock glacier belts we argue that paleoclimate significance of the presented geomorphological record may match paleobotanical proxy reconstructions and the results of climate simulations but only if the impact of enhanced temperature seasonality on glacier mass balance and rock glacier activity is taken into account

latest pleistocene and holocene glacier variations in the european alps in the alps climatic conditions reflected in glacier and rock glacier activity in the earliest holocene show a strong affinity to conditions in the latest pleistocene younger dryas glacier advances in the alps related to younger dryas cooling led to the deposition of egesen stadial moraines egesen stadial moraines can be divided into three or in some cases even more phases sub stadials moraines of the earliest and most extended advance the egesen maximum stabilized at 12 2 1 0 ka based on 10be exposure dating at the schonferwall tyrol austria and the julier pass outer moraine switzerland final stabilization of moraines at the end of the egesen stadial was at 11 3 0 9 ka as shown by 10be data from four sites across the alps from west to east the sites are piano del praiet northwestern italy grosser aletschgletscher central switzerland julier pass inner moraine eastern switzerland and val viola northeastern italy there is excellent agreement of the 10be ages from the four sites in the earliest holocene glaciers in the northernmost mountain ranges advanced at around 10 8 1 1 ka as shown by 10be data from the kartell site northern tyrol austria in more sheltered drier regions rock glacier activity dominated as shown for example at julier pass and larstig valley tyrol austria new 10be dates presented here for two rock glaciers in larstig valley indicate final stabilization no later than 10 5 0 8 ka based on this data we conclude the earliest holocene between 11 6 and about 10 5 ka was still strongly affected by the cold climatic conditions of the younger dryas and the preboreal oscillation with the intervening warming phase having had the effect of rapid downwasting of egesen glaciers at or slightly before 10 5 ka rapid shrinkage of glaciers to a size smaller than their late 20th century size reflects markedly warmer and possibly also drier climate between about 10 5 ka and 3 3 ka conditions in the alps were not conducive to significant glacier expansion except possibly during rare brief intervals past tree line data from kaunertal tyrol austria in concert with radiocarbon and dendrochronologically dated wood fragments found recently in the glacier forefields in both the swiss and austrian alps points to long periods during the holocene when glaciers were smaller than they were during the late 20th century equilibrium line altitudes ela were about 200 m higher than they are today and about 300 m higher in comparison to little ice age lia elas the larstig rock glacier site we dated with 10be is the type area for a postulated mid holocene cold period called the larstig oscillation presumed age about 7 0 ka our data point to final stabilization of those rock glaciers in the earliest holocene and not in the middle holocene the combined data indicate there was no time window in the middle holocene long enough for rock glaciers of the size and at the elevation of the larstig site to have formed during the short infrequent cold oscillations between 10 5 and 3 3 ka small glaciers less than several km2 may have advanced to close to their lia dimensions overall the cold periods were just too short for large glaciers to advance after 3 3 ka climate conditions became generally colder and warm periods were brief and less frequent large glaciers for example grosser aletschgletscher advanced markedly at 3 0 2 6 ka around 600 ad and during the lia glaciers in the alps attained their lia maximum extents in the 14th 17th and 19th centuries with most reaching their greatest lia extent in the final 1850 1860 ad advance

climate at the equilibrium line of glaciers the relationships between temperature precipitation and radiation on glacier equilibrium lines are investigated using 70 glaciers for which the mass balance and meteorological observations have been carried out for sufficiently long periods it is found that the characteristic climate at glacier equilibrium lines can be described using the summer 3 months temperature in a free atmosphere annual total precipitation and the sum of global and long wave net radiation all of these are measured at or very near the equilibrium line altitudes then it is shown how the shift of the equilibriumline will occur as a result of a climatic change finally the effect of the shift of the equilibrium line on the annualmean specific mass balance is analytically derived and compared with observations the present results make it possible to identify the altitudes in climate models where glacierization should begin and to evaluate the mass balance changes as a result of possible future changes in the climate

trimlines blockfields mountain top erratics and the vertical dimensions of the last british irish ice sheet in nw scotland periglacial trimlines separating glacially eroded lower slopes from blockfield covered plateaus on british and irish mountains have been interpreted either 1 in terms of representing the maximum altitude of the last ice sheet during the last glacial maximum lgm or 2 as a thermal boundary separating wet based ice at pressure melting point from cold based ice on summit plateaus we test these competing hypotheses through 10be exposure dating of high level erratic boulders above trimlines on five mountains in nw scotland nine out of 14 erratics yielded post lgm exposure ages ranging from 14 0 0 7 ka to 16 5 0 9 ka or from 14 9 0 9 ka to 17 6 1 1 ka depending on the 10be production rate employed in exposure age calculation these ages refute hypothesis 1 as they imply that the last ice sheet overtopped the mountains preservation of apparently intact blockfields on the summits implies cold based ice cover supporting hypothesis 2 as altitudinally consistent high level trimlines extend from our sampled sites across much of nw scotland and the hebrides our conclusions apply to all trimlines in this broader area and probably to all high level trimlines elsewhere in the british isles preservation of blockfields under cold based ice is consistent with blockfield evolution on plateaus throughout much or all of the quaternary averaged exposure ages of 15 16 ka for plateau top erratics implies nunatak emergence from the downwasting ice sheet prior to a regional readvance of the ice margin the wester ross readvance and before rapid warming at 14 7 ka at the onset of the lateglacial interstade but after the timing of ice sheet thinning as retrodicted by recent proxy climate driven thermo mechanical coupled models our findings provide an additional constraint on the future development of such models by implying that high level trimlines represent the altitude of a former transition zone between ice at pressure melting point and ice below pressure melting point

periglacial trimlines in the scottish highlands abstract two periglacial weathering limits have been identified on mountains in the highlands of scotland the lower has been interpreted as a periglacial trimline marking the upper limits of loch lomond younger dryas stade glaciers and has been employed to reconstruct the dimensions of parts of the main west highland icefield and certain smaller glaciers and icefields interpretation of the upper weathering limit has been more contentious but recent research has demonstrated 1 significant contrasts in the degree of bedrock weathering above and below this limit 2 that gibbsite a pre devensian weathering product is abundant above the limit but rare in soils farther downslope 3 that the isotopic 26al age of bedrock exposures above the limit greatly exceeds that at lower altitudes and 4 that the altitude of the weathering limit descends regularly along former ice sheet flowlines collectively these attributes suggest that the upper weathering limit is a periglacial trimline defining the maximum altitude of the last ice sheet calculated basal shear stress values are consistent with this interpretation which implies that the mainland ice shed lay at ca 900 m in wester ross and descended gently northwards whilst harris and lewis in the outer hebrides supported an independent ice cap that achieved a maximum altitude of ca 700 m wider implications of this interpretation and the future potential for ice sheet reconstruction are explored

timing of glacier advances and climate in the high tatra mountains western carpathians during the last glacial maximum during the last glacial maximum lgm long valley glaciers developed on the northern and southern sides of the high tatra mountains poland and slovakia chlorine 36 exposure dating of moraine boulders suggests two major phases of moraine stabilization at 26 21 ka lgm i maximum and at 18 ka lgm ii the dates suggest a significantly earlier maximum advance on the southern side of the range reconstructing the geometry of four glaciers in the sucha woda panszczyca mlynicka and velicka valleys allowed determining their equilibrium line altitudes elas at 1460 1460 1650 and 1700 m asl respectively based on a positive degree day model the mass balance and climatic parameter anomaly temperature and precipitation has been constrained for lgm i advance modeling results indicate slightly different conditions between northern and southern slopes the n s ela gradient finds confirmation in slightly higher temperature at least 1 c or lower precipitation 15 on the south facing glaciers during lgm i the precipitation distribution over the high tatra mountains indicates potentially different lgm atmospheric circulation than at the present day with reduced northwesterly inflow and increased southerly and westerly inflows of moist air masses

soft sediment deformation structures in cave deposits and their possible causes kalacka cave tatra mts poland abstract clastic deposits in kalacka cave in the tatra mts show soft sediment deformation structures ssds rare for a cave environments the poorly sorted allochthonous sediments were deposited within a cave sump under a fluvial regime likely due to glacially initiated back flooding during the last glacial the structures include small scale faults normal and reverse folds upright symmetric anticlines low amplitude open folds w vergent folds and fault propagation folds and water escape structures a laboratory experiment is used to assess the possibile liquefaction of a thin soft sediment filling in a limestone tube including calculation of the site effects of resonance frequency and amplification coefficient and the site vulnerability index kg the calculations indicate that seismic waves can be amplified up to 10 times and the expected resonance frequency is 17 05 hz we argue that the observed ssds formed in two stages first brittle and ductile deformation structures developed due to gravity induced slumping next liquefaction produced water escape structures the studied ssds were likely seismically triggered favorable conditions occurred during the withdrawal of the last glacier mis 2 when the sediments were oversaturated and the tatra mts experienced a strong earthquake m7 0 alternatively high frequency microearthquakes could have been triggered by slope failure cutting into kalacka cave

extent and deglacial chronology of the last british irish ice sheet implications of exposure dating using cosmogenic isotopes over 160 10be and 36cl exposure ages pertaining to the extent and chronology of the last british irish ice sheet biis are critically reviewed despite uncertainties inherent in the use of exposure ages this approach has demonstrated that at the last glacial maximum lgm ca 26 21 ka the biis extended over all low ground in scotland and all or almost all of ireland consistent with recent models depicting extension of the last biis to the atlantic shelf edge all exposure ages obtained for high level sites above trimlines on the mountains of northwestern scotland and ireland pre date the lgm this finding confirms that high plateaux in these areas escaped significant glacial erosion probably under a protective cover of cold based glacier ice that remained frozen to the underlying substrate in terms of deglaciation chronology the southern irish sea basin was probably deglaciated by 19 18 ka with extensive deglaciation of low ground in ireland and northeastern scotland prior to ca 14 5 ka ice cover on low ground in northwestern scotland apparently persisted after 14 0 ka suggesting survival of ice in favourable locations during the lateglacial interstade ca 14 5 12 9 ka attempts to date readvances have had mixed success the wester ross readvance in northwestern scotland was initially dated to ca 16 3 ka but more recent research implies a much younger age ca 14 0 13 5 ka exposure ages indicating a prolonged stillstand during ice sheet retreat in the cairngorms at ca 14 5 14 0 ka conflict with ages obtained on postglacial rockslides and basal radiocarbon dates which indicate deglaciation before ca 15 5 15 0 ka exposure dating has been successfully employed to confirm a loch lomond stadial ca 12 9 11 5 ka age for moraines in several mountain areas and to constrain the minimum altitude of the ice cap that extended over the western grampians at that time copyright 2009 john wiley sons ltd

ice thickness and topographic relief in glaciated landscapes of the western usa abstract the development of relief in glaciated landscapes plays a crucial role in hypotheses relating climate change and tectonic processes in particular glaciers can only be responsible for peak uplift if they are capable of generating significant relief in formerly nonglaciated landscapes previous work has suggested that relief in glaciated landscapes should scale with the thickness of the ice here we summarise a field based test of this hypothesis in two mountain ranges in the western united states the sierra nevada california and the sangre de cristo range colorado these areas exhibit a range of degrees of glacial occupation during the quaternary including some drainage basins essentially unoccupied by ice allowing a detailed exploration of how relief in different parts of a drainage basin evolves in response to glacial modification we mapped last glacial maximum lgm trimlines to estimate the ice thickness at the equilibrium line altitude during the lgm and determined several metrics of relief for drainage basins across the full spectrum of lgm ice extents comparison between measures of relief and ice thickness estimates indicates that relief production in glaciated mountain belts scales with ice thickness and consequently also drainage area we extended our study to the bitterroot range in idaho montana and the teton range in wyoming for a more comprehensive understanding of sub ridgeline relief or missing mass this measure of mean relief is surprisingly little affected by either the degree of glacial modification or the total material removed by glaciers but appears to be influenced by the more active tectonics of the teton range while the effects of glacial modification on the landscape are clear valley widening hanging valley formation the overall change in the relief structure of the mountain ranges studied here is surprisingly modest

glacial dynamics at the beginning of termination i in the eastern alps and their stratigraphic implications abstract results of a geological re investigation of the type localities of the buhl stadial the supposed first halt during ice decay of the inn glacier in the basin of hopfgarten and at the southern flank of the mountain range wilder kaiser northern tyrol austria are presented it is shown that in this region no stationary or advancing inn glacier tongue existed following the last glacial maximum lgm ice extent all sedimentary and morphological evidence indicates that large parts of the inn glacier and all other eastern alpine valley glaciers became stagnant followed by massive down wasting hence this period after the lgm at the beginning of termination i wurm lateglacial is best defined as phase of early lateglacial ice decay which can be tentatively correlated to greenland stadial 2c 21 2 19 5 kyr bp only smaller glaciers advanced towards their lateglacial maximum position lmp this happened mostly due to short lasting climatic oscillations as indicated in the windau valley hopfgarten and at steinach am brenner a mechanically induced glacier advance is reconstructed for the cirque glaciers of the wilder kaiser at an advanced stage of down melting they lost their blockade established by the inn glacier during lgm and advanced downvalley it is proposed to define the processes of this phase by lithostratigraphic type sections

relict landslide development as inferred from speleothem deformation tectonic data and geoelectrics abstract the direct dating of pre and postfaulting dislocated calcite speleothems afforded new insight into slope failure in the tatra mountains in southern poland a multi approach study of the karstic kalacka cave non crevasse type enabled us to infer the slope deformation structure which had been poorly preserved in ground surface topography using combined methods including geomorphological and structural mapping of cave and ground surfaces paleostress analysis near surface electrical resistivity tomography ert and induced polarization methods ip uranium series dating 234u 230th calcite microtexture analysis and stable isotope 18o and 13c analysis here slope deformation began with dilation between 280 7 ka and 265 8 ka and proceeded as deep seated gravitational slope deformations the final stage consisted of dilation rejuvenation and rockfall during the latest pleistocene or holocene post 35 4 ka additionally some dilations are evident beyond the extent of the landslide detected by ert indicating further progradation of slope failure since this failure was initiated during the climatic transition from mis 9 to mis 8 stable isotope analysis of calcite flowstone layers was applied to test climate factors the correlation of calcite microtexture and 18o and 13c compositional changes with the interval of dilation activity indicates that regional environment factors chiefly an increase in precipitation probably contributed to slope destabilization

synchronisation of palaeoenvironmental events in the north atlantic region during the last termination a revised protocol recommended by the intimate group abstract the north atlantic intimate group of the inqua palaeoclimate commission has previously recommended an event stratigraphy approach for the synchronisation of records of the last termination using the greenland grip isotopic record as the regional stratotype and intcal98 for the calibration of radiocarbon dates lowe j j hoek w intimate group 2001 inter regional correlation of palaeoclimatic records for the last glacial interglacial transition a protocol for improved precision recommended by the intimate project group quaternary science reviews 20 1175 1187 here we present a revised protocol for time stratigraphic correlation in the north atlantic region over a more extended time period 30 8 ka this employs the new ngrip isotopic record and associated greenland ice core chronology 2005 gicc05 as the regional stratotype intcal04 for the calibration of radiocarbon dates bayesian based statistical procedures for the construction of age models and tephrochronology to validate correlations between regional site records

a stratigraphic framework for abrupt climatic changes during the last glacial period based on three synchronized greenland ice core records refining and extending the intimate event stratigraphy due to their outstanding resolution and well constrained chronologies greenland ice core records provide a master record of past climatic changes throughout the last interglacial glacial cycle in the north atlantic region as part of the intimate integration of ice core marine and terrestrial records project protocols have been proposed to ensure consistent and robust correlation between different records of past climate a key element of these protocols has been the formal definition and ordinal numbering of the sequence of greenland stadials gs and greenland interstadials gi within the most recent glacial period the gs and gi periods are the greenland expressions of the characteristic dansgaard oeschger events that represent cold and warm phases of the north atlantic region respectively we present here a more detailed and extended gs gi template for the whole of the last glacial period it is based on a synchronization of the ngrip grip and gisp2 ice core records that allows the parallel analysis of all three records on a common time scale the boundaries of the gs and gi periods are defined based on a combination of stable oxygen isotope ratios of the ice 18o reflecting mainly local temperature and calcium ion concentrations reflecting mainly atmospheric dust loading measured in the ice the data not only resolve the well known sequence of dansgaard oeschger events that were first defined and numbered in the ice core records more than two decades ago but also better resolve a number of short lived climatic oscillations some defined here for the first time using this revised scheme we propose a consistent approach for discriminating and naming all the significant abrupt climatic events of the last glacial period that are represented in the greenland ice records the final product constitutes an extended and better resolved greenland stratotype sequence against which other proxy records can be compared and correlated it also provides a more secure basis for investigating the dynamics and fundamental causes of these climatic perturbations

glacial chronology and palaeoclimate in the bystra catchment western tatra mountains poland during the late pleistocene abstract deglaciation chronology of the bystra catchment western tatra mountains has been reconstructed based on 10be exposure age dating fourteen rock samples were collected from boulders located on three moraines that limit the horizontal extent of the lgm maximum advance and the lateglacial recessional stage the oldest preserved maximum moraine was dated at 15 5 0 8 ka an age that could be explained more likely by post depositional erosion of the moraine such scenario is supported by geomorphologic and palaeoclimatological evidence the younger cold stage is represented by well preserved termino lateral moraine systems in the kondratowa and sucha kasprowa valleys the distribution of the moraine ridges in both valleys suggest a complex history of deglaciation of the area the first late glacial re advance lg1 was followed by a cold oscillation lg2 that occurred at around 14 0 0 7 13 7 1 2 ka glaciers during both stages had nearly the same horizontal extent however their thickness and geometry changed significantly mainly due to local climatic conditions triggered by topography controlling the exposition to solar radiation the lg1 stage occurred probably during the pre bolling cold stage greenland stadial 2 1a however the lg2 stage can be correlated with the cooling at around 14 ka during the greenland interstadial 1 gi 1d older dryas this is the first chronological evidence of the older dryas in the tatra mountains the ela of the maximum bystra glacier was located at 1480 m a s l in accordance with the ela in the high tatra mountains during the lgm during the lg1 and lg2 stages the ela in the catchment rose up to 1520 1530 m a s l and was located approximately 100 150 m lower than in the eastern part of the massif climate modelling results show that the bystra glacier maximum advance could have advanced in the catchment when mean annual temperature was lower than today by 11 12 c and precipitation was reduced by 40 60 this is in accordance with lgm conditions previously reported for the high tatras during the lg1 and lg2 stages the temperature decrease in the study area reached 10 c and precipitation was lower by 30 compare to modern conditions this resulted in slightly higher accumulation 20 30 in the western tatra mountains compare to the high tatra mountains

late pleistocene and holocene glaciation in the pyrenees a critical review and new evidence from 10be exposure ages south central pyrenees a compilation and a critical assessment of the 14c data set available show that the chronology of glacial events in the pyrenees is not well constrained after reviewing the literature on glacial reconstruction we suggest a simplified subdivision of the pyrenean last glacial cycle record into last pleniglacial deglaciation and neoglacial to improve the numerical glacial chronology we provide 10be surface exposure ages for 5 glacial erosion surfaces 9 moraines and 2 erratics in the upper noguera ribagorcana valley south central pyrenees published corrected 14c data and new 10be exposure ages indicate that the major phase of moraine building recorded in this valley during the last pleniglacial probably occurred after 25 ka bp this age calls in question the generally accepted hypothesis of a very early deglaciation of the pyrenees ca 70 40 ka bp and strongly suggests that the pyrenees could have been in pleniglacial conditions during the last glacial maximum lgm however we do not exclude the possibility that the maximum glacier extent during the last glacial cycle had taken place much earlier than the lgm as indicated by some published u th ams 14c and osl data we suggest that pleniglacial conditions could have taken place during a longer 30 20 ka period than generally assumed and that the last pleniglacial could include several glacier fluctuations recorded irregularly in different valleys with a last major glacier readvance taking place around the lgm in addition the deglaciation is represented by a series of moraines deposited between ca 13 7 0 9 and 10 1 0 6 ka this moraine series indicates a highly variable climatic pattern that is partly correlated with greenland stadial 1 the younger dryas and suggests that the deglaciation could have continued into the early holocene

an event stratigraphy for the last termination in the north atlantic region based on the greenland ice core record a proposal by the intimate group it is suggested that the grip greenland ice core should constitute the stratotype for the last termination based on the oxygen isotope signal in that core a new event stratigraphy spanning the time interval from ca 22 0 to 11 5 k grip yr bp ca 19 0 10 0 k 14 c yr bp is proposed for the north atlantic region this covers the period from the last glacial maximum through termination 1 of the deep ocean record to the pleistocene holocene boundary and encompasses the last glacial late glacial of the traditional northwest european stratigraphy the isotopic record for this period is divided into two stadial episodes greenland stadials 1 gs 1 and 2 gs 2 and two interstadial events greenland interstadials 1 gi 1 and 2 gi 2 in addition gi 1 and gs 2 are further subdivided into shorter episodes the event stratigraphy is equally applicable to ice core marine and terrestrial records and is considered to be a more appropriate classificatory scheme than the terrestrially based radiocarbon dated chronostratigraphy that has been used hitherto 1998 john wiley sons ltd

glacier response in the european alps to heinrich event 1 cooling the gschnitz stadial the gschnitz stadial was a period of regionally extensive glacier advance in the european alps that lies temporally between the breakdown of the last glacial maximum piedmont lobes and the beginning of the bolling warm interval moraines of the gschnitz stadial are found in medium to small catchments are steep walled and blocky and reflect a snowline lowering of 650 700 m in comparison to the little ice age reference snowline 10 be surface exposure dating of boulders from the moraine at the type locality at trins gschnitz valley tyrol austria shows that it stabilised no later than 15 400 1400 yr ago the overall morphological situation and the long reaction time of the glacier suggest that the climatic downturn lasted about 500 300 yr indicating that the gschnitz cold period began approximately 15 900 1400 yr ago if not somewhat earlier this is consistent with published radiocarbon dates that imply that the stadial occurred sometime between 15 400 14 c yr bp 18 020 19 100 cal yr and 13 250 14 c yr bp 15 360 16 015 cal yr a palaeoclimatic interpretation of the gschnitz glacier based on a simple glacier flow model and statistical glacier climate models shows that precipitation was about one third of modern day precipitation and summer temperatures were about 10 k lower than today in comparison during the younger dryas precipitation in this area was only about 10 less and ts summer temperature was only 3 5 4 k lower than modern values based on the age of the moraine and the cold and dry climate at that time we suggest that the gschnitz stadial was the response of alpine glaciers to cooling of the north atlantic ocean associated with heinrich event 1 copyright 2005 john wiley sons ltd

in situ cosmogenic exposure ages from the isle of skye northwest scotland implications for the timing of deglaciation and readvance from 15 to 11 ka we present 10 in situ cosmogenic exposure ages from two moraines on the isle of skye the strollamus medial moraine was deposited during deglaciation of the devensian ice sheet and yields a mean exposure age from five samples of 14 3 0 9 ka the moraine age indicates that a significant ice mass existed on skye at the time of a regional readvance recorded in wester ross northwest scotland taken at face value the ages suggest that deglaciation did not occur until well into greenland interstade 1 the slapin moraine represents the local limit of the loch lomond readvance llr and yields a mean exposure age from five samples of 11 5 0 7 ka which is consistent with deposition relating to the llr these ages suggest that the maximum extent may have been reached late in the stadial and that some glaciers may have remained active until after the climatic amelioration that marks its end this scenario is considered unlikely given the nature of the climate during this period which leads us to call for a locally calibrated production rate copyright 2011 john wiley sons ltd

cosmic ray production rates of 10be and 26al in quartz from glacially polished rocks we have studied the concentrations of 10be and 26al in quartz crystals extracted from glacially polished granitic surfaces from the sierra nevada range these surfaces were identified with the glacial advance during the tioga period 11 000 years ago our measurements yield the most accurate estimates to date for the absolute production rates of these nuclides in sio2 due to cosmic ray nucleons and muons for geomagnetic latitudes 43 8 44 6 n and altitudes 2 1 3 6 km the estimates are relatively free from uncertainties in snow cover since we studied a suite of rock surfaces inclined 0 75 with respect to the horizontal the principal uncertainty arises due to the lack of a precise date for the glacial retreat event about 10 the 26al 10be ratio at production 6 0 is determined more accurately since the exposure age of the samples is 2 orders of magnitude smaller than the mean lives of the two nuclides production rates of 10be and 26al in quartz at other latitudes and altitudes in the troposphere can be determined from the present measurements by scaling using the known altitude and latitude dependence of cosmic ray fluxes of nucleons and negative muons knowledge of the production rates of these nuclides is a prerequisite for their application in erosion and geomorphological studies

the glacial history of the dinaric alps montenegro abstract large areas of montenegro were glaciated during the pleistocene this paper presents evidence from the massifs of central montenegro including durmitor and sinjajevina moracke planine maganik prekornica and vojnik glacial deposits have been subdivided on the basis of morphostratigraphy and soil weathering and 31 u series ages from cemented tills provided a geochronological framework the largest glaciation occurred before 350 ka when a series of conjoined ice caps over the massifs of central montenegro covered a total area of nearly 1500 km 2 these formed during mis 12 and correspond with the largest skamnellian stage glaciations in greece to the south later middle pleistocene glaciations occurred during the penultimate glacial cycle correlating with the vlasian stage in greece mis 6 when ice caps covered an area of 720 km 2 over central montenegro there is also geochronological evidence of glacial deposits dating from the interval between mis 12 and mis 6 before the interglacial complex of mis 7 this glaciation appears to have been very similar in extent to that which occurred during mis 6 the last glacial cycle in central montenegro was characterised by valley and cirque glaciers covering a total area of 49 km 2 it is very likely that glaciers have been present in the mountains of central montenegro during every glacial cycle since a small glacier still survives today the smaller glaciers of the last glacial cycle are likely to have been associated with summer temperatures that were warmer than those of earlier cold stages the striking contrast in the extent and thickness of ice cover during the cold stages of the pleistocene has an important bearing on the geomorphological and biological evolution of the balkans

post lgm faulting in central europe lidar detection of the 50 km long sub tatra fault western carpathians abstract the increasing availability of high resolution lidar data reveals surprisingly strong topographic evidence of late quaternary faulting in some intraplate regions characterized by weak recent tectonic activity for the first time we present evidence of a 50 km long post last glacial maximum lgm tectonic rupture along the southern margin of the tatra mountains slovakia in the highest part of the carpathian mountains using a high resolution 1 1 m lidar dem we recognize that the normal range bounding sub tatra fault stf and its eastward branch the ru bachy fault rbf offset late quaternary glacial moraines alluvial fans and colluvial slopes the fault zone morphology is dominated by a nearly continuous southward facing up to 18 m high main scarp locally accompanied by antithetic fault scarps and hanging wall grabens similar offsets of pre lgm and lgm deposits and the absence of fault scarps within holocene alluvium suggest that the stf and rbf were active for a relatively short time interval between 18 ka and the holocene using the vertical separation of dated lgm moraine crests we estimate that the minimum average postglacial slip rates along the stf and rbf varied from 0 1 0 3 mm year i e rates one order of magnitude higher than those reported for other faults in central europe additionally deep seated landslides and the presence of large rock avalanches along the fault suggest possible postglacial high magnitude earthquake s producing coseismic rupture of the stf and rbf we conclude that 1 southern range bounding faults of the tatra mountains are the longest 50 km and only documented post lgm ruptures revealing extensive offset of late quaternary deposits in the western carpathians and 2 relatively small along strike variations in postglacial offset mimic the long term exhumation trends and imply en block uplift of the southern margin of the tatra mountains with the highest displacement along the east stf

glaciation in the rila mountains bulgaria during the last glacial maximum abstract relict glacial landform complexes have been studied in the mountains of the central balkan peninsula since the end of the 19th century since their existence was proved for the first time by cvijic various authors have debated the number of glacial phases as well as their age at present the problem of age determination is being solved by the application of the new methods for numerical dating this paper is a detailed study of the maximum glaciation in the rila massif which is the highest mountain in bulgaria and in the whole balkan peninsula the application of cosmogenic nuclide dating 10be on moraine samples confirmed that the largest extent of former glaciers that left moraine deposits was around the time of the last glacial maximum most probably the maximum extent occurred in two phases the first around the beginning and the second around the end of the lgm 24 23 ka bp and 18 16 ka bp respectively separated by a retreat phase during the coldest but also driest phase of the glacial stage the gis processed calculations on the basis of field evidence of the former glacier extent and the preliminary calculations of the equilibrium line altitude ela through the accumulation ablation ratio aar method show that the ela during the lgm had quite small differences throughout the rila massif from about 2150 to 2200 m a s l in the nw to about 2250 2290 m in the se despite the considerable differences in terminal moraine depositional altitudes from 1150 to 2000 m a s l this is due to both the complicated pattern in the directions of moisture supply and to the influences of local topography

the utility of statistical analysis in structural geology abstract recent advances in statistical methods for structural geology make it possible to treat nearly all types of structural geology field data these methods provide a way to objectively test hypotheses and to quantify uncertainty and their adoption into standard practice is important for future quantitative analysis in structural geology we outline an approach for structural geologists seeking to incorporate statistics into their workflow using examples of statistical analyses from two locations within the western idaho shear zone in the west mountain location we test the published interpretation that there is a bend in the shear zone at the kilometer scale directional statistics on foliations corroborate this interpretation while orientation statistics on foliation lineation pairs do not this discrepancy leads us to reconsider an assumption made in the earlier work in the orofino location we present results from a full statistical analysis of foliation lineation pairs including data visualization regressions and inference these results agree with thermochronological evidence that suggests that the orofino area comprises two distinct subparallel shear zones the r programming language scripts that were used for both statistical analyses can be downloaded to reproduce the statistical analyses of this paper

landscape similarity retrieval and machine mapping of physiographic units abstract we introduce landscape similarity a numerical measure that assesses affinity between two landscapes on the basis of similarity between the patterns of their constituent landform elements such a similarity function provides core technology for a landscape search engine an algorithm that parses the topography of a study area and finds all places with landscapes broadly similar to a landscape template a landscape search can yield answers to a query in real time enabling a highly effective means to explore large topographic datasets in turn a landscape search facilitates auto mapping of physiographic units within a study area the country of poland serves as a test bed for these novel concepts the topography of poland is given by a 30 m resolution dem the geomorphons method is applied to this dem to classify the topography into ten common types of landform elements a local landscape is represented by a square tile cut out of a map of landform elements a histogram of cell pair features is used to succinctly encode the composition and texture of a pattern within a local landscape the affinity between two local landscapes is assessed using the wave hedges similarity function applied to the two corresponding histograms for a landscape search the study area is organized into a lattice of local landscapes during the search the algorithm calculates the similarity between each local landscape and a given query our landscape search for poland is implemented as a geoweb application called terraex pl and is available at http sil uc edu given a sample or a number of samples from a target physiographic unit the landscape search delineates this unit using the principles of supervised machine learning repeating this procedure for all units yields a complete physiographic map the application of this methodology to topographic data of poland results in the delineation of nine physiographic units the resultant map bears a close resemblance to a conventional physiographic map of poland differences can be attributed to geological and paleogeographical input used in drawing the conventional map but not utilized by the mapping algorithm

surface exposure dating 36cl and 10be of post last glacial maximum valley moraines lake district northwest england some issues and implications surface exposure ages 36cl and 10be have been obtained from 16 boulders at the margins of and within the limits of former valley glaciers at four sites in the lake district northwest england the established view is that the lake district functioned as an independent centre of ice dispersal during the last glacial maximum lgm 26 21 ka of the dimlington stade greenland stades 2 3 and that the glacial depositional landforms at the sampled sites are products of stillstands or readvances of the ice margins following the lgm however several of the apparent 36cl surface exposure ages pre date rather than post date the lgm it is inferred that these boulders retain levels of 36cl inherited from a previous period of exposure rather than indicating moraine formation prior to the lgm and their subsequent survival beneath lgm ice an implication is that lake district glaciers achieved limited erosion of bedrock during the build up to and at the maximum of the lgm and that glacial erosion rates increased at a late stage in that period single 36cl and 10be exposure ages from two sites suggest a stillstand or readvance of valley glaciers prior to the loch lomond younger dryas stade lls greenland stade 1 and windermere lateglacial interstade greenland interstade 1 but additional ages are required in order to confirm or refute these individual ages an lls age for glacial depositional landforms at both these sites had previously been proposed 36cl surface exposure ages for boulders on moraines within the lls limit do not fully support emplacement at that time there is a possibility that these moraines are associated with a pre lls stillstand or readvance of the valley glacier copyright 2013 john wiley sons ltd

last glacial maximum and lateglacial in the polish high tatra mountains revised deglaciation chronology based on the 10 be exposure age dating abstract deglaciation chronology of the polish high tatra mountains has been reconstructed based on 10 be exposure age dating fifty seven rock samples were collected from boulders located on the terminal and lateral moraines that limit the horizontal extent of the lgm and the lateglacial glaciers in the biala woda and sucha woda catchments the uncertainty weighted mean age of 21 5 2 5 ka obtained for the maximum terminal moraine in the sucha woda valley indicates that the oldest preserved moraines were formed during the global lgm the age population ranges between 15 1 1 0 and 28 3 2 0 ka and suggests that glaciers reached their maximum position lgm i as early as 28 25 ka and the final stabilization of the form occurred much later possibly after melting of buried dead ice the younger glacial oscillation lgm ii occurred no later than 20 5 ka and is represented by well preserved termino lateral moraine systems in the panszczyca valley the first lateglacial stage lg1 in the study area is documented in the rybi potok valley at the rp1 moraine 1300 m a s l which was stable at around 16 6 0 3 ka the younger lg2 stage has no defined absolute age however it is constrained between 16 5 and 15 5 ka by the timing of the lg3 stage this cold event is represented by well formed moraines in the roztoka piec stawow polskich rybi potok and panszczyca valleys of which exposure age indicates their deposition between 15 0 0 5 and 15 6 0 1 ka the lg1 lg2 and lg3 stages likely occurred during the oldest dryas cold stage greenland stadial 2 1a related to the north atlantic cooling heinrich event 1 the youngest glacial oscillation is evidenced by moraines in the pusta and panszczyca valleys these moraines are composed of very large granitic blocks of which exposure ages often exhibit isotope inheritance this is reflected by the youngest p3 moraine in the panszczyca valley with a mean age of deposition close to the lgm the r4 moraine system in the pusta valley however indicates two oscillations phases that occurred at around 13 ka and correlates well with the timing of rp5 moraine formation in the za mnichem valley the lg4 stage is related to the climate cooling during the younger dryas greenland stadial 1 lgm elas reconstructed for the biala woda and sucha woda panszczyca glaciers were located at 1460 1480 m a s l during the oldest dryas stages the ela in the high tatras rose from 1600 to 1650 m a s l in the rybi potok valley and from 1700 to 1800 m a s l in the roztoka piec stawow polskich valley the younger dryas ela depending on glacier s exposition was located between 1950 and 2000 m a s l climate modelling results show that the lgm glaciers maximum advance could have advanced in the high tatras when the mean annual temperature was lower than today by 11 12 c and precipitation was reduced by 40 60 during the lateglacial stages the temperature decrease in the study area changed from 10 c during the oldest dryas to 6 c during the younger dryas and precipitation lowering decreased from 50 to 30 or even 10 respectively compare to modern conditions

heinrich events massive late pleistocene detritus layers of the north atlantic and their global climate imprint 1 millennial climate oscillations of the glacial interval are interrupted by extreme events the so called heinrich events of the north atlantic their near global footprint is a testament to coherent interactions among earth s atmosphere oceans and cryosphere on millennial timescales heinrich detritus appears to have been derived from the region around hudson strait it was deposited over approximately 500 250 years several mechanisms have been proposed for the origin of the layers binge purge cycle of the laurentide ice sheet jokulhlaup activity from a hudson bay lake and an ice shelf buildup collapse fed by hudson strait to determine the origin of the heinrich events i recommend 1 further studies of the timing and duration of the events 2 further sedimentology study near the hudson strait and 3 greater spatial and temporal resolution studies of the layers as well as their precursory intervals studies of previous glacial intervals may also provide important constraints

palaeogeography and 10be exposure age chronology of middle and late pleistocene glacier systems in the northern pyrenees implications for reconstructing regional palaeoclimates abstract we present constraints on the chronology palaeogeography and palaeoclimatic implications for western europe of middle and late pleistocene glaciation in the ariege catchment north eastern pyrenees based on 37 cosmogenic 10 be exposure ages obtained from moraines and glacially scoured bedrock exposures we have dated six regional glacial stades the chronology emphasises several conclusions that are new to the region i in the pyrenees the global lgm occurred several thousands of years after the maximum ice extent of the wurmian glaciation ii almost full glacier extent occurred again during the global lgm but only in the eastern pyrenees iii valley glaciers such as in the ariege trunk valley attained lengths of 25 km during the oldest dryas stadial the cosmogenic exposure ages additionally provide the first direct evidence of 10 km scale fluctuations of ice front positions during the late pleistocene glacial cycle probably at the time of marine isotope stage 3 as well as rare insights into middle pleistocene ice margin positions compared with existing evidence of glacial palaeogeography in other catchments of the pyrenan range the data also reveal a sharp contrast in relative ice extent between the glacierized catchments of the eastern pyrenees ariege carol malniu tet where wurmian mie and lgm ice fronts reached similar positions and the rest of the range where ice fronts at the time of the mis 2 and global lgm palaeotemperature minima lagged far behind the wurmian mie terminal moraines we ascribe this non uniform behaviour among catchments to non uniform palaeoclimatic conditions along the strike of the pyrenees a range of palaeoenvironmental proxies reviewed in the literature highlight a sharp difference in sea surface temperatures between the warmer western mediterranean and the cooler bay of biscay the consequences of such an e w temperature gradient on weather patterns during the global lgm are compatible with a strengthening of mediterranean low pressure systems particularly the semi permanent balearic low generating greater precipitation over the eastern pyrenees compared to atlantic weather systems further west

glaciations and paleoclimate of mount erciyes central turkey since the last glacial maximum inferred from 36cl cosmogenic dating and glacier modeling abstract forty four boulders from moraines in two glacial valleys of mount erciyes 38 53 n 35 45 e 3917 m central turkey dated with cosmogenic chlorine 36 36cl indicate four periods of glacial activity in the past 22 ka 1 ka 1000 calendar years last glacial maximum lgm glaciers were the most extensive reaching 6 km in length and descending to an altitude of 2150 m above sea level these glaciers started retreating 21 3 0 9 ka 1 ago they readvanced and retreated by 14 6 1 2 ka ago lateglacial and again by 9 3 0 5 ka ago early holocene the latest advance took place 3 8 0 4 ka ago late holocene using glacier modeling together with paleoclimate proxy data from the region we reconstructed the paleoclimate at these four discrete times the results show that lgm climate was 8 11 c colder than today and moisture levels were somewhat similar to modern values with a range between 20 more and 25 less than today the analysis of lateglacial advance suggests that the climate was colder by 4 5 6 4 c based on up to 1 5 times wetter conditions the early holocene was 2 1 4 9 c colder and up to twice as wet as today while the late holocene was 2 4 3 c colder and its precipitation amounts approached to similar conditions as today our paleoclimate reconstructions show a general trend of warming for the last 22 ka and an increase of moisture until early holocene and a decrease after that time the recent glacier terminates at 3450 m on the northwest side of the mountain it is a remnant from the last advance possibly during the little ice age repeated measurements of glacier length between 1902 and 2008 reveal a retreat rate of 4 2 m per year which corresponds to a warming rate of 0 9 1 2 c per century