the vegetation and climate history of the last glacial cycle in a new pollen record from lake fimon southern alpine foreland n italy abstract the sediments of lake fimon n italy contain the first continuous archive of the late pleistocene environmental and climate history of the southern alpine foreland we present here the detailed palynological record of the interval between termination ii and the last glacial maximum the age depth model is obtained by radiocarbon dating in the uppermost part of the record downward we correlated major forest expansion and contraction events to isotopic events in the greenland ice core records via a stepping stone approach involving intermediate correlation to isotopic events dated by tims u th in alpine and apennine stalagmites and to pollen records from marine cores of the iberian margin modelled ages obtained by bayesian analysis of deposition are thoroughly consistent with actual ages with maximum offset of 1700 years sharp expansion of broad leaved temperate forest and of sudden water table rise mark the onset of the last interglacial after a treeless steppe phase at the end of penultimate glaciation this event is actually a two step process which matches the two step rise observed in the isotopic record of the nearby antro del corchia stalagmite respectively dated to 132 5 2 5 and 129 1 5 ka at the interglacial decline mixed oak forests were replaced by oceanic mixed forests the latter persisting further for 7 ka till the end of the eemian succession warm temperate woody species are still abundant at the eemian end corroborating a steep gradient between central europe and the alpine divide at the inception of the last glacial after a stadial phase marked by moderate forest decline a new expansion of warm broad leaved forests interrupted by minor events and followed by mixed oceanic forests can be identified with the north alpine saint germain i the spread of beech during the oceanic phase is a valuable circumalpine marker the subsequent stadial interstadial succession lacking the telocratic oceanic phase is also consistent with the evidence at the north alpine foreland the middle wurmian full glacial is marked by persistence of mixed forests dominated by conifers but with significant lime and other broad leaved species a major arboreal pollen decrease is observed at modelled age of 38 7 0 5 ka larch expansion and last occurrence of lime which has been related to heinrich event 4 the evidence of afforestation persisting south of the alps throughout most of mis 3 contrasts with a boreal and continental landscape known for the northern alpine foreland pointing to a sharp rainfall boundary at the alpine divide and to southern air circulation this is in agreement with the alpine paleoglaciological record and is supported by the pressure and rainfall patterns designed by mesoscale paleoclimate simulations strenghtening the continental high pressure during the full glacial triggered cyclogenesis in the middle latitude eastern europe and orographic rainfall in the eastern alps and the balkanic mountains thus allowing forests development at current sea level altitudes

luminescence dating of proglacial sediments from the eastern alps the potential of optically stimulated luminescence osl for dating proglacial deposits is tested here at three last glacial key sites in the eastern alps this was undertaken using both sand sized feldspar and quartz grains as well as fine silt sized material the samples reveal rather poor luminescence intensities of the investigated quartz grains and it is also clearly demonstrated that several of the deposits were incompletely bleached prior to deposition bleaching experiments were carried out and different approaches for extracting the aliquots where the osl was completely bleached prior to burial were tested applying different osl measurement techniques and analytical procedures we investigated which approach was most appropriate for dating known age proglacial sediments best results were achieved using single aliquot regenerative dose methodology on coarse grain quartz and feldspar samples in combination with the approach of preusser et al 2007 luminescence dating of proglacial sediments from switzerland boreas in press for ed calculation

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

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

unravelling the moisture sources of the alpine glaciers using tunnel valleys as constraints a lack of archives has impeded reconstructions of moisture pathways for past glaciations in the european alps here we focus on the confluence area of two palaeoglaciers in the swiss plateau that were sourced on the northern aare glacier and southern sides valais glacier of the european alps we mapped tunnel valleys in the region using a drilling database based on which we inferred the relative extent of each glacier c 270 ka ago when the valleys were formed we then compared this situation with that of the lgm we found that while the valais glacier expanded farther into the foreland than the aare glacier during the lgm the opposite was the case c 270 ka ago we also found that lgm glaciers were non erosive in the distal foreland these contrasts in extents and erosional efficiencies imply differences in moisture pathways between the lgm and the time when the tunnel valleys were formed

response of fluvial aeolian and lacustrine systems to late pleistocene to holocene climate change lower moravian basin czech republic abstract late pleistocene to holocene morava river valley fill of the eastern czech republic reflects the geomorphic evolution of the valley as forced by climate change valley fill stratigraphy was studied through measured sections optically stimulated luminescence osl and radiocarbon dating ground penetrating radar surveys of relict sand dunes archived drill hole data and a comparison of elevations and ages of stratigraphic units fluvial systems evolved from meandering with floodplains to braided during mis 3 braided fluvio aeolian systems dominated through mis 2 and the last glacial maximum lgm valley aggradation occurred during arid glacial times of a low water to sediment discharge ratio most valley fill was removed at 13 ka with incision by a large bend meandering river with an estimated bankful paleodischarge 3 larger than the modern morava river the holocene morava river has varied from meandering to anabranching with low rates of floodplain aggradation the bzenec sand body up to 36 m thick represents an erosional remnant bypassed during late pleistocene incision and consists of interpreted lacustrine turbidites overlain by braided stream and aeolian dune strata the turbidites consist of laterally continuous thin normally graded beds of rounded and frosted sand grains of aeolian origin dates and elevation data argue that the valley lake formed during the lgm through downstream damming by a braided terminal fan and sand dune complex the turbidites are interpreted to have formed through fluvial undercutting and slumping of dune accumulations as lake level rose this process forced an erosional unroofing of aeolian accumulations reflected in inverted osl dates for the turbidites

loess in europe mass accumulation rates during the last glacial period abstract upper pleistocene loess palaeosol sequences provide excellent high resolution terrestrial archives of climate forcing due to improvements in numerical age determinations especially in luminescence dating methods a more reliable time based reconstruction of the past climate and environmental change has become available for the loess record in europe chronological information was collected from 43 sites along a northwest to southeast transect in europe thirty three of these sites had sufficient age information to allow estimation of mass accumulation rates and it was possible to isolate the mass accumulation rates of primary loess during the last glacial period 28 13 ka bp at 21 of these locations these sites fall along a coarse climatic gradient from the relatively coastal climate of belgium and france to the drier more continental climate of central europe interpreting mass accumulation rates of loess in terms of this climatic gradient is not straightforward as these deposits are dominated by sources in floodplains and large river systems thus accumulation rates are influenced strongly by regional wind and precipitation patterns but mostly by the availability of glacially derived material from the alps and the periglacial terrains that characterized european fluvial systems during and immediately following glaciation

glacier advances in northeastern turkey before and during the global last glacial maximum abstract our study in the basyayla valley in northeastern anatolia showed evidence of four glacier advances that built terminal and lateral moraines surface exposure dating of boulders on these moraines showed that the maximum ice extent mie was asynchronous with the global last glacial maximum lgm 22 1 4 3 thousand years ka the local mie took place at least 57 0 3 5 ka ago the extent of the basyayla glacier during this advance is not known exactly because the boulders are only preserved on a lateral moraine the next advance was prior to 41 5 2 5 ka and it descended down the valley to approximately 2320 m above sea level m a s l with a glacier length of 5 3 km during the early global lgm the basyayla glacier extended for a distance of 4 9 km down to approx 2430 m a s l the last recorded advance occurred during the global lgm this extension was 0 7 km smaller than the local mie and its terminus reached 2490 m a s l only the exposure ages of boulders in a retreat position at an altitude of approx 3045 m a s l indicate that the valley has remained ice free since the lateglacial period therefore the lateglacial extent was limited to the cirque system in the uppermost part of the catchment furthermore holocene glacier oscillations seem to be either absent or restricted to solifluction in the whole catchment and to rock glacier movements in the southern tributary of the basyayla valley system

environmental and climatic conditions at a potential glacial refugial site of tree species near the southern alpine glaciers new insights from multiproxy sedimentary studies at lago della costa euganean hills northeastern italy abstract it has been hypothesized that refugia of thermophilous tree species were located in northern italy very close to the alps though this hypothesis has yet to be tested thoroughly in contrast to central and southern italy with its relative wealth of data only a few fragmentary records are currently available from northern italy for the last glacial wurm weichselian our new study site lago della costa lies adjacent to the catchment of the megafans of the alpine forelands and the braided rivers of the northeastern po plain that have so far inhibited the recovery of continuous glacial and late glacial records we analyze pollen plant macrofossils charcoal and ostracods to reconstruct the vegetation fire and lake history for the period 33 000 16 000 cal bp we compare our data with glacial records from southern europe to discuss similarities and dissimilarities between these potential refugial areas a comparison with independent paleoclimatic proxies allows to assess potential linkages between environmental and climatic variability new macrofossil and pollen data at lago della costa unambiguously document the local persistence of boreal tree taxa such as larix decidua and betula tree species around the study site during the last glacial the regular occurrence of pollen of temperate trees in the organic lake sediments fine detritus calcareous gyttja suggests that temperate taxa such as corylus avellana quercus deciduous tilia ulmus fraxinus excelsior carpinus abies alba and fagus sylvatica most likely survived the last glacial maximum lgm at favorable sites in the euganean hills the percentage values of temperate trees are comparable with those from southern europe e g monticchio in southern italy we conclude that the euganean hills were one of the northernmost refugial areas of temperate taxa in europe however the relative and absolute abundances of pollen of temperate trees are highly variable pollen inferred declines of temperate tree communities e g quercetum mixtum and low ostracod inferred water levels at lago della costa correspond to the cold heinrich events h 2 lgm 23 000 19 000 cal bp and h 3 around 28 000 cal bp as recorded in the marine sediments of the north atlantic similar patterns of significant temperate tree population collapses during cold heinrich events are recorded at southern mediterranean sites e g monticchio and the alboran sea these findings suggest close linkages between northern atlantic and south central european climates during the past glacial

sm nd evidence for 3 3 ga old rocks in rajasthan northwestern india abstract tonalitic to granodioritic gneisses from the basement gneiss of the aravalli region northwestern india define a sm nd isochron corresponding to an age of 3 31 0 07 ga and an initial nd isotopic ratio that is close to chondritic lenticular bodies of mafic amphibolites within the gneisses however define an isochron corresponding to a younger age of 2 83 0 05 ga and small positive initial nd this age is similar to that reported for a large intrusive granite the untala granite in this area and combined with field evidence suggests that mafic volcanism may have been associated with formation of the granite a highly hree enriched garnet separate from one of the tonalitic gneisses defines a two point garnet wholerock isochron age of 2 45 0 02 ga which also is similar to the age of a known thermal event in the region intrusion of the berach and bundelkhand granites at approximately 2 5 ga these results document in broad outline archean crustal formation events in the northwestern segment of the indian subcontinent and demonstrate the need for more detailed studies of the complex terranes mapped by heron 1953 as a single unit the banded gneiss complex

interhemispheric anti phasing of rainfall during the last glacial period abstract we have obtained a high resolution oxygen isotopic record of cave calcite from caverna botuvera 27 13 s 49 09 w southern brazil which covers most of the last 36 thousand years ka with an average resolution of a few to several decades the chronology was determined with 46 u th ages from two stalagmites tests for equilibrium conditions show that oxygen isotopic variations are primarily caused by climate change we interpret our record in terms of meteoric precipitation changes hence the variability of south american monsoon sam intensity the oxygen isotopic profile broadly follows local insolation changes and shows clear millennial scale variations during the last glacial period with amplitudes as large as 3 but with smaller centennial scale shifts 1 during the holocene the overall record is strikingly similar to but strongly anti correlated with a number of records from the northern hemisphere we compared our record to other precisely dated contemporaneous records from hulu cave eastern china minima in 18o wet periods intense sam at our site are synchronous with maxima in 18o dry periods weak east asian monsoon eam in eastern china within precise dating errors and vice versa this anti phased precipitation relationship between two low latitude locations may be interhemispheric in extent based on comparison with records from other sites precipitation anti phasing may be related to north south shifts in the mean position of the intertropical convergence zone itcz and asymmetry in hadley circulation in two hemispheres associated not with seasonal changes as observed today but with millennial scale climate shifts the millennial scale atmospheric see saw patterns that we observe could have important controls and feedbacks on climate within hemispheres because of water vapor s greenhouse properties

new geomorphological and chronological constraints for glacial deposits in the rivoli avigliana end moraine system and the lower susa valley western alps nw italy our new dataset from the rivoli avigliana end moraine system the westernmost amphitheatre of the italian alps provides an important step towards understanding foreland reaching glaciations before and during the last glacial maximum lgm in the western alps 10be data from six boulders in pre lgm deposits gave ages between 26 8 2 1 and 41 2 1 9 ka based on morphological and pedological data we interpret the oldest age as a minimum age for the glacier advance s 10be results suggest that the lgm occurred in two major steps during the first at 24 0 1 5 ka several ridges were constructed demonstrating oscillation of the dora riparia glacier snout at the maximum position our data demonstrate a significantly larger lgm extent in the rivoli avigliana amphitheatre than shown on previous maps the maximum advance was followed by a short re advance of the glacier at 19 6 0 9 ka as recorded by 10be ages from boulders in lateral positions along the lower susa valley the maximum ice surface during the lgm was at 1000 920 m a s l in the final reach of the valley 560 620 m of elevation above the alluvial plain and at 620 340 m a s l at the continuous moraines in the amphitheatre

origin of komatiite at high pressures abstract experimental melting relations to 20 gpa demonstrate that the commonly accepted model of komatiite formation by non invariant melting olivine liquid is too restrictive komatiites could also have formed by pseudoinvariant melting olivine pyroxene garnet liquid modified spinel majorite liquid along the anhydrous solidus at high pressures the mgo content of komatiites cannot be used to infer the degree of partial melting in the mantle there would have been little change in mgo at a high pressure pseudoinvariant point even for degrees of partial melting that ranged from very small to over 80 instead the mgo content of komatiites may be a better indication of the depth of partial melting than it is the degree of partial melting late archean komatiites containing 20 28 mgo could have been generated at depths ranging from about 130 to 260 km early archean komatiites from the barberton mountain land could have formed at depths corresponding to the present day transition zone or at shallower levels from an unusually primitive mantle source komatiites which originated by partial melting in a lower mantle formed by majorite fractionation should have geochemical characteristics that have not yet been reported this indicates that either melting did not extend into the lower mantle or if it did the upper and lower mantles were isolated by a chemical and thermal boundary layer in archean times

paleoenvironments from robust loess stratigraphy using high resolution color and grain size data of the last glacial krems wachtberg record ne austria abstract the complex interplay of dust sedimentation pedogenesis and erosion reworking in the formation of loess paleosol sequences lps challenges paleoenvironmental proxies here we show that color and grain size are essential parameters characterizing loess profiles and support robust stratigraphies as a basis for reconstructions in the context of local geo ecological and large scale paleoclimatic evolution detailed paleoenvironmental records from the period since the arrival of anatomically modern humans to the last glacial maximum are scarce in the alpine surroundings the c 7 5 m thick lps krems wachtberg ne austria known for its well preserved upper paleolithic context at a depth of 5 5 m formed between 40 and 20 ka bp by quasi continuous dust sedimentation interrupted by phases of incipient pedogenesis and local reworking the new kw2015 composite is based on three sections studied and sampled at 2 5 cm resolution color and grain size data support a robust stratigraphy for reconstructions of the pedosedimentary evolution the marked transition from oxidized to reduced paleosols of kw2015 around 34 35 ka corresponds to the middle to upper pleniglacial transition as part of a general cooling trend from marine isotope stage mis 3 to 2 intensely modulated by millennial scale climatic fluctuations as recorded in the greenland ice core data the distinct response of kw2015 to these trends highlights that reconstructing lps evolution based on a robust stratigraphy is a prerequisite to paleoenvironmental proxy interpretation

mammoths inside the alps during the last glacial period radiocarbon constraints from austria and palaeoenvironmental implications abstract this study examines remains of the woolly mammoth mammuthus primigenius found inside the austrian alps an area occupied by an extensive ice stream network during the last glacial maximum the data demonstrate that these cold steppe adapted animals locally migrated several tens of kilometers into alpine valleys radiocarbon analyses constrain the age of these fossils to the first half of marine isotope stage 3 documenting ice free conditions in major valleys at that time we also provide a list of all traceable austrian sites of mammuthus primigenius totaling about 230 localities compiled through 15 museums and collections in austria the vast majority of these findings are from the corridors of the danube and mur rivers and their tributaries and the adjacent loess covered foreland of the alps areas that were never ice covered during pleistocene glaciations

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

present status of the geochronology of the precambrian rocks of rajasthan abstract age determinations mostly by rb sr analyses of the precambrian rocks of rajasthan by us and by others are summarized and discussed broad periods of acid magmatism at 1 3000 2900 m y 2 2600 2500 m y 3 2000 1900 m y 4 1700 1500 m y and 5 850 750 m y were identified the oldest rocks in the area are the yet undated banded gneisses bgc east of udaipur intruded by the untala granite dated at 2950 m y and hence of mid archean age the basal status hitherto attributed to the berach granite dated at 2600 m y is no longer tenable the radiometric control on the beginning and duration of the overlying aravalli supergroup is not yet satisfactory though a lower limit at 2000 m y is indicated heron s original delhi rocks have recorded two magmatic events widely separate in space and time while the earliest granitic activity at 1600 m y is recorded only in the alwar basin in the northeast the younger activity between 850 750 m y is widespread as shown by the nearly concordant ages of erinpura type granites along the aravalli mountain range and the malani rhyolites in the western plains of the aravalli range

near synchronous interhemispheric termination of the last glacial maximum in mid latitudes isotopic records from polar ice cores imply globally asynchronous warming at the end of the last glaciation however 10be exposure dates show that large scale retreat of mid latitude last glacial maximum glaciers commenced at about the same time in both hemispheres the timing of retreat is consistent with the onset of temperature and atmospheric co2 increases in antarctic ice cores we suggest that a global trend of rising summer temperatures at the end of the last glacial maximum was obscured in north atlantic regions by hypercold winters associated with unusually extensive winter sea ice

sea surface temperature variability during the last glacial interglacial cycle assessing the magnitude and pattern of climate change in the north atlantic abstract sea surface temperature and salinity estimates reconstructed using planktonic foraminiferal abundance and 18o records from core su90 03 40 n 32 w 2475 m water depth reveal large climatic fluctuations linked to major instabilities in northern hemisphere ice sheets over the last 150 000 years episodes of enhanced ice rafted detritus ird input were accompanied by discrete temperature minima representing coolings of between 4 and 8 c and reductions in surface salinity of up to 2 5 3 5 several additional cooling episodes of a similar magnitude were documented during intervals of low ird input that appear to be synchronous within the limits of dating with ice rafting events spatially confined to higher latitudes accelerator mass spectrometer 14c dates for heinrich events h1 14 2 ka h2 21 4 ka h3 26 7 ka h4 34 8 ka h5 47 2 ka obtained from core su90 03 agree well with other published age estimates and suggest a contemporaneous pattern of climate change throughout the north atlantic during the last glacial period this interpretation is supported by a comparison of ird and palaeotemperature records from dsdp site 609 and core su90 03 which clearly shows that the major climatic fluctuations identified at high latitudes were transmitted toward the subtropics however 14c dates suggest that ice rafting episodes may be diachronous to some extent the northward migration of the polar front after the h1 event at 40 n in the mid atlantic occurred at 14 ka approximately 500 years earlier than along the portuguese margin where the southerly advection of polar waters persisted within eastern boundary current system

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

on eustatic sea level history last glacial maximum to holocene abstract this paper addresses the question of the magnitude and time dependence of the globally averaged eustatic rise of sea level that occurred subsequent to the time of last glacial maximum lgm at approximately 21 000 calendar years before present through the analysis of relative sea level rsl histories predicted by a realistic mass conserving and gravitationally self consistent theory of postglacial sea level change it is demonstrated that there are preferred oceanic locations at which this eustatic function is well approximated by local sea level history one such location is the island of barbados in the caribbean sea a site from which a coral based record exists that extends from mid holocene to lgm because of the sea level ambiguity that is inherent to coral based records however it is important that the global ice equivalent eustatic sea level curve inferred on the basis of the barbados data be tested against observations at other locations from which similarly extensive records are also available but which are derived on the basis of sea level indicators which are not subject to the ambiguities inherent to corals it is shown that when the eustatic function employed in the global theoretical model is tuned so as to enable the model to fit the barbados observations where the maximum relative sea level rsl depression is assumed to be near 120 m then the theory misfits the record from the sunda shelf in the indonesian archipelago as well as the record from j bonaparte gulf in northern australia both of these recently published records appear to constrain the lgm low stand of rsl to a value above 120 m the implications of these results for interpretation of the long coral derived records from the huon peninsula of papua new guinea and the island of tahiti are also discussed

the problem of the precambrian basement in rajasthan western india abstract the banded gneissic complex bgc of rajasthan considered to form the basement underlying the precambrian proterozoic aravalli metasediments shows an erosion surface marked by a conglomerate and an angular unconformity with gneissic foliation crossing the metasedimentary bands at only a few places the bgc is a composite gneiss evolved by extensive migmatization of metasedimentary rocks of diverse composition and possibly metaigneous rocks the contact between the bgc and the aravalli rocks is a gently curved surface whereas the gneissic foliation as well as the large scale metasedimentary enclaves within the gneissic complex show all the intricate patterns of super imposed folding traceable in the aravalli rocks this implies that the basement gneisses have been involved in ductile deformation with the aravalli rocks the migmatization being synkinematic with the first deformation in the latter all these apparently conflicting lines of evidence can be resolved if the gneisses as we see them now represent not the original but the mobilized basement with the bgc aravalli boundary representing for a large part a migmatite front rather than the original basement cover interface only at a few places was there a chance of the original basement escaping mobilization and thus little chance of identifying this original interface

environmental processes of the ice age land oceans glaciers epilog knowledge of the state of the earth at the last glacial maximum lgm an interval around 21 000 years ago is an important benchmark for understanding the sensitivity of global environmental systems to change much progress in understanding climates of the lgm has occurred in the 20 years since the end of the climap project of the 1970s climate long range investigation mapping and prediction here we review this progress based on presentations and discussion at a rst open science meeting of the epilog project environmental processes of the ice age land oceans glaciers held in delmenhorst germany may 1999 we outline key controversies and document protocols for epilog contributions so that a new synthesis of the lgm earth can emerge as an open project of the world s community of scientists 2001 elsevier science ltd all rights reserved

palaeoecology of quaternary periglacial environments during ois 2 in the forefields of the salzach glacier upper austria palaeopedological sedimentological and palaeoecological investigations were carried out on the pleniglacial loess deposits of duttendorf austria in the area of the pleistocene salzach glacier detailed insights into the past climate topography and vegetation especially during the oxygen isotopic stage 2 ois 2 were obtained according to the results it seems that alluvial processes played a more important role for the genesis of the loess deposits during the late glacial maximum lgm than previously assumed the pollen record plant macro remains and malaco fauna yield the occurrence of hygrophilous taxa as well as of water plants by consequence the sediment can be regarded as alluvial loess furthermore the results show that the landscape corresponded not only to a cold and dry loess steppe environment but was also partly influenced by humid conditions and that probably even small water bodies may have existed

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

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

presence of cave bears in western austria before the onset of the last glacial maximum new radiocarbon dates and palaeoclimatic considerations tischoferhohle and pendling barenhohle near kufstein tyrol are among the only locations where remains of cave bear ursus spelaeus group were found in the western part of austria one sample from each site was radiocarbon dated four decades ago to ca 28 14c ka bp here we report that attempts to date additional samples from pendling barenhohle have failed due to the lack of collagen casting doubts on the validity of the original measurement we also unsuccessfully tried to date flowstone clasts embedded in the bone bearing sediment to provide maximum constraints on the age of this sediment ten cave bear bones from tischoferhohle showing good collagen preservation were radiocarbon dated to 31 1 39 9 14c ka bp again pointing towards an age underestimation by the original radiocarbon dated sample from this site these new dates from tischoferhohle are therefore currently the only reliable cave bear dates in western austria and constrain the interval of cave occupation to 44 3 33 5 cal ka bp we re calibrate and re evaluate dates of alpine cave bear samples in the context of available palaeoclimate information from the greater alpine region covering the transition into the last glacial maximum eventually leading to the demise of this megafauna

fe rich archean tholeiites derived from melt enriched mantle sources evidence from the kolar schist belt south india tholeiitic amphibolites in the circa 2700 ma kolar schist belt south india are intimately interlayered with minor komatiitic amphibolites the tholeiitic amphibolites which are similar to other archean tholeiitic rocks are fe enriched with feo total varying from about 9 to 13 wt olivine and plagioclase have similar calculated saturation surface temperatures ranging from about 1125 to 1225 c on many trace and major element plots there is a distinct compositional gap between the komatiitic and tholeiitic amphibolites that cannot be explained by density filtering because the calculated melt densities for the komatiitic 2 73 2 79 and tholeiitic 2 61 2 72 amphibolites nearly overlap the rare earth element ree patterns for the tholeiites are flatter and have lower light ree abundances than those for many of the associated komatiitic rocks modeling of major and trace element data suggests that the tholeiitic rocks are not related to the komatiitic rocks by 1 differentiation of magmas of

geochemistry and petrogenesis of late archaean aravalli volcanics basement enclaves and granitoids rajasthan abstract major trace and rare earth element data are presented for the basal volcanics of the aravalli supracrustal sequence for the mafic enclaves within the banded gneiss complex bgc adjacent to the supracrustals and for granitoids within the bgc and their petrogenesis discussed with regard to the problematic relationship between basement and cover in terms of major elements the aravalli lavas range from magnesian 22 mgo komatiites or picrites to fe rich tholeftes but differ from a typical archaean greenstone volcanic sequence in that their trace element patterns are relatively enriched in incompatible and light rare earth elements moreover the range of patterns observed requires a number of distinct mantle sources as well as different degrees of melting there are two distinct types of mafic enclave within the bgc the larger lenses correspond quite well with the range of variation seen in the aravalli sequence and could be feeders the other type close to the bgc aravalli junction has more alkalic characteristics high nb zr and could represent rift volcanics or tectonically accreted fragments of ocean islands the data suggest that the aravalli sequence is not an accreted oceanic terrane but are more consistent with interaction of a deep mantle plume with rather mature sub continental lithosphere the early archaean age of parts of the bgc the chemistry of the granitoids and the alkaline character of the enclaves are also broadly compatible with this model the character of the aravalli sequence is intermediate between that of an archaean greenstone belt and a phanerozoic flood basalt province

a new radiocarbon chronology of baumkirchen stratotype for the onset of the upper wurmian in the alps the start of the upper wurmian in the alps was marked by massive fluvioglacial aggradation prior to the arrival of the central alpine glaciers in 1984 the subcommission on european quaternary stratigraphy defined the clay pit of baumkirchen in the foreland of the inn valley austria as the stratotype for the middle to upper wurmian boundary in the alps key for the selection of this site was its radiocarbon chronology which still ranks among the most important datasets of this time interval in the alps in this study we re sampled all available original plant specimens and established an accelerator mass spectrometry chronology which supersedes the published 40 year old chronology the new data show a much smaller scatter and yielded slightly older conventional radiocarbon dates clustering at ca 31 14c ka bp when calibrated using intcal13 the new data suggest that the sampled interval of 653 681 m in the clay pit was deposited 34 36 cal ka bp using two new radiocarbon dates of bone fragments found in the fluvioglacial gravel above the banded clays allows us to constrain the timing of the marked change from lacustrine to fluvioglacial sedimentation to ca 32 33 cal ka bp which suggests a possible link to the heinrich 3 event in the north atlantic copyright 2013 john wiley sons ltd

alpine evidence for atmospheric circulation patterns in europe during the last glacial maximum the configuration of alpine accumulation areas during the last glacial maximum lgm has been reconstructed using glacial geological mapping the results indicate that the lgm ice surface consisted of at least three major ice domes all located south of the principal weather divide of the alps this implies that the buildup of the main alpine ice cover during oxygen isotope stage ois 2 was related to precipitation by dominant southerly atmospheric circulation in contrast to today s prevalent westerly airflow such a reorganization of the atmospheric circulation is consistent with a southward displacement of the oceanic polar front in the north atlantic and of the associated storm track to the south of the alps these results combined with additional paleoclimate records from western and southern europe allow an interpretation of the asynchronous evolution of the different european ice caps during the last glaciation 18o stages ois 4 and 3 were characterized by location of the polar front north of 46 n gulf of biscay this affected prevailing westerly circulation and thus ice buildup in western scandinavia the pyrenees vosges and northern alps at the lgm however the polar front lay at 44 n causing dominating southerly circulation and reduced precipitation in central and northern europe

wet to dry climatic trend in north western iberia within heinrich events abstract the direct sea land correlation applied to core md99 2331 retrieved from the north western iberian margin shows a two phase pattern within heinrich events 4 2 and 1 in the ocean and in the adjacent landmasses changes between wet cold and dry cool conditions in the iberian peninsula detected during these extreme events cannot be explained by a simple oceanographic mechanism related to changes in the strength of the atlantic meridional overturning circulation here we propose an additional atmospheric mechanism able to produce this scenario based on the comparison between the md99 2331 record and other available palaeoclimate sequences from the north atlantic region 18 75 n and 0 75 w the climatic asymmetry observed between mid and subtropical eastern north atlantic latitudes wet dry and the blake outer ridge dry wet during h4 h2 and h1 can be explained by changes in the position of the atlantic jet stream during the first phase of h4 h2 and h1 the atlantic jet stream was located further south following the southward displacement of the oceanic thermal front as far south as 35 37 n on the contrary during the second phase of h4 h2 and h1 the jet stream was located further north following the northward displacement of this thermal front as far north as 42 n from the atmospheric point of view these two phases are reminiscent of the present day negative and positive prevailing modes of the north atlantic oscillation nao respectively but high resolution studies of additional north atlantic key sites and climate simulations are needed to confirm the hypothesis of a nao like mechanism operating on millennial timescales

the relationship of heinrich events and their european precursors over the past 60 ka bp a multi proxy ice rafted debris provenance study in the north east atlantic high resolution multi proxy records of ice rafted debris ird flux and provenance in the ne atlantic detail the development variability and decline of marine margins of the last glacial circum north atlantic ice sheets coupled lithological identification sr and nd isotopic composition and 40ar 39ar ages of individual hornblende grains reduce ambiguity as to ird potential source region allowing clear differentiation between laurentide lis icelandic and british bis ice sheet sources the icelandic and bis are collectively referred to as the nw european ice sheet nweis a step wise increase in the flux of ird to the core site at 26 5 ka bp documents bis advance and glaciation of ireland millennial scale variability of the bis at a 2 ka periodicity is inferred through clusters of pulsed ird fluxes throughout the late glacial 26 5 10 ka bp combination of these european ird events and the 7 ka periodicity of lis instability is thought to account for quasi synchronicity of the nweis and lis ird pulses at heinrich event h 2 and h1 previously suggested to represent the possible involvement of the nweis in the initiation of h events furthermore the lack of extensive nweis marine margin is inferred prior to h3 31 5 ka bp such that no european precursor event is associated with either h5 or h4 this suggests that precursor events were not directly implicated in the collapse of the lis and the persistent instabilities of the bis that are clustered at a 2 ka periodicity are incompatible with the concept that both h events and their precursors are independent responses to a common underlying trigger

high resolution mapping of glacial landforms in the north alpine foreland austria abstract in this study results from traditional field mapping were merged with precise elevation information from airborne lidar light detection and ranging surveys morphological and sedimentological data provide new results from the austrian eastern part of the salzach piedmont glacier during times of and shortly after the last glacial maximum lgm the variations in meltwater discharge had a major impact on the development of glacial landforms in areas with high meltwater supply erosional or debris reworking processes play a major role represented by drainage channels drumlins and kettled low relief hummocky moraine with low slope angles low discharge areas are associated with distinct depositional forms such as high relief end moraines up to 30 m and hummocky moraine averaging 20 m with high slope angles isolated conical kames may reach heights up to 45 m fluvial activity is supposed to rise towards the end of the glacial cycle causing high melting rates and comprehensive debris reworking the formation of terminal lakes and associated widespread inorganic lake clays are the last deposits within the study area before the salzach glacier completely receded to its main valley the survey of glacial landforms through the combination of field mapping and high resolution dem derived from airborne lidar missions gives precise information on transport and deposition during the last glacial cycle of the eastern salzach glacier piedmont lobe

inner gorge slot canyon system produced by repeated stream incision eastern alps significance for development of bedrock canyons abstract many inner bedrock gorges of the alps show abrupt downstream changes in gorge width as well as channel type and gradient as a result of epigenetic incision of slot canyons many slot canyons also are associated with older gorge reaches filled with quaternary deposits the age of slot canyons and inner bedrock gorges however commonly is difficult to constrain for the inner bedrock gorge system of the steinberger ache catchment eastern alps active slot canyons as well as older abandoned gorge reaches filled with upper wurmian proglacial deposits record three phases of gorge development and slot canyon incision a 234u 230th age of cement of 29 7 1 8 ka in fluvial conglomerates onlapping the flank of an inner gorge fits with late wurmian valley bottom aggradation shortly before pleniglacial conditions in addition the age indicates that at least the corresponding canyon reach must be older during advance of ice streams in the buildup of the last glacial maximum lgm the catchment was blocked and a proglacial lake formed bedrock gorges submerged in that lake were filled with fluviolacustrine deposits during the lgm the entire catchment was overridden by ice during post glacial reincision streams largely found again their preexisting inner bedrock canyons in some areas however the former stream course was missed and a slot canyon formed the distribution of pleistocene deposits the patterns of canyon incision and the mentioned u th cementation age however together record a further discrete phase of base level rise and stream incision well before the lgm the present course of steinberger ache and its tributaries is a patchwork of 1 slot canyons incised during post glacial incision 2 vestiges of slot canyons cut upon an earlier middle to late wurmian cycle of base level rise and fall 3 reactivated reaches up to 200 m in width of inner bedrock gorge that are watershed at present and more than at least 30 ka in age and 4 abandoned sediment filled reaches of bedrock canyons that also must be older than 30 ka and that are exposed alongside the active streams multi cyclic bedrock canyon systems composed of reaches of markedly different ages may be common in mountain ranges subject to glaciations and or mass wasting

dating the onset of lgm ice surface lowering in the high alps abstract the general chronological outline of the last glacial maximum lgm in the alps is well known after more than two centuries of ice age research in europe current studies focus on resolving the details of the deglaciation process after the lgm particularly few data in this context are available from the high alps here we report chronological constraints on the onset of deglaciation in two different study areas from the western and eastern alps the mont blanc italy and zillertal alps austria we sampled 32 bedrock and boulder surfaces from high elevation ridges beneath the glacial trimline the oldest 10 be exposure ages of 18 5 ka correspond to the initiation of lowering of the lgm ice surface identical ages from both study areas suggest synchronous decay of the lgm glaciers in the accumulation zones of the western and eastern alps thus the high alpine ice surface lowered roughly synchronously to the downwasting of the glacier tongues in the forelands that was completed 19 18 ka in both study areas ages of numerous samples that are consistently 2 3 ka younger than 18 5 ka suggest the persistance of remnant ice patches at high elevations in the lateglacial accumulation zones approximately until the bolling allerod interstadial

periodic hotspot distribution and small scale convection in the upper mantle hotspots are commonly attributed to mantle plumes and to a first order the hotspot distribution is correlated with long wavelength geoid anomalies and with higher temperatures in the lower mantle suggesting that the plumes are generated in the lower mantle i show that the second order distribution is periodic with a typical spacing of 800 1000 km such a spacing would be too narrow for plumes to ascend directly from the lower mantle but is close to the thickness of the upper mantle the alignment of convection cells in the upper mantle seems to control the periodicity to reconcile the first a and second order distributions assuming limited mass fluxes across the 670 km boundary a lateral deflection of plumes as they breach the transition zone from below is required

melt segregation from partially molten source regions the importance of melt density and source region size the compressibility of basic melt at 1 atmosphere is about an order of magnitude higher than that of mantle minerals consequently the density contrast between melt and the principal residual crystals in mantle source regions is expected to decrease with increasing source region depth the increasingly olivine normative character of primary melts produced at greater depths is also expected to result in a decrease in this density contrast with increasing source region depth once vertical permeability is established by melt generated during partial melting buoyancy driven melt percolation can under some circumstances segregate melt from the residual crystals in its source region on a geologically rapid time scale limits to this process are provided by cooling of the source region freezing melt in and rigidity of the crystalline matrix mechanically trapping melt source region size influences these limits strongly consequently small partially molten diapirs km in diameter may be able to trap large melt fractions 30 but larger source regions would be unable to do so the reduction in density contrast with pressure reduces the buoyant force driving melt percolation and provides another limit to melt segregation diapirs at depth may thus stably contain large fractions of melt but may decompress and unload their melt during ascent this effect would be enhanced in small diapirs and may be relevant to the genesis of komatiitic magma melt compression may also be a factor in explaining why the very different maximum depths inferred for typical basic melt segregation from source regions on different planets 500 km on the moon 250 km on mars 100 km on earth correspond to similar pressures 25 35 kbar at greater pressures melt may no longer be capable under ordinary conditions of segregating upwards by buoyancy this may also help to explain why depleted peridotites overlie more fertile peridotites and how deep regions of the mantle are able to remain fertile over geologic time

chronology of the last glacial maximum in the salzach palaeoglacier area eastern alps a chronostratigraphy based on luminescence data was established at a key loess profile duttendorf in the northern alpine foreland of austria the data help to constrain the timing and duration of the last glacial maximum lgm in the area of one of the largest east alpine piedmont glaciers the salzach palaeoglacier climate deterioration and maximum advance of this glacier were coeval with the beginning of the main loess accumulation phase in the glacier forefield at 29 30 ka a late lgm outwash gravel layer deposited on top of the loess profile marks the end of the lgm glacier activity at 20 ka the geomorphological setting around the loess profile provides evidence of a major glacier oscillation during the course of the lgm a phenomenon qualitatively known from other alpine palaeoglaciers but never interpreted in terms of palaeoclimate a lgm glacier oscillation similar to that of the salzach palaeoglacier was reported recently from the south alpine tagliamento palaeoglacier suggesting a common forcing the onset of loess deposition at duttendorf and the tentatively contemporal advance of the salzach palaeoglacier reflect as do other data the drastic cooling in europe as a result of heinrich event 3 the first glacier maximum is not well constrained in the study area but a correlation with the better dated tagliamento amphitheatre suggests a possible response to heinrich 2 the second re advance occurred synchronously within dating uncertainties in both palaeoglaciers forefields at 21 ka but the forcing mechanism remains unknown copyright 2011 john wiley sons ltd

bizarre geochemistry of komatiites from the crixas greenstone belt brazil komatiite lava flows in the crixas greenstone belt goias brazil have textures and volcanic structures typical of archean komatiites but are geochemically most unusual the flows are porphyritic and massive or layered with spinifex upper parts and olivine cumulate lower parts mgo contents range from 18 to 40 in such lavas only olivine and minor chromite can have crystallized but neither major nor trace elements fall on olivine control lines in mgo variation diagrams cao and sr fall on lines with slopes steeper than olivine control lines sio2 feo na2o k2o and y show little systematic variation zr shows a large variation that does not correlate with mgo and al2o3 decreases markedly with decreasing mgo the aberrant behaviour is highlighted by the ree rare earth elements in spinifex and olivine cumulate layers from three flows in the spinifex layers chondrite normalized ree patterns are hump shaped with maxima at nd or sm la sm n 0 6 gd yb n 1 6 2 3 whereas cumulate zones in the same flows have steadily sloping patterns with lree enriched relative to hree la sm n 1 3 gd yb n 1 4 neither normal magmatic processes acting during emplacement of the komatiites nor thermal erosion and wall rock assimilation can explain these effects and we speculate that elements commonly thought of as immobile e g al zr ree migrated during hydrothermal alteration or metamorphism a pb pb whole rock isochron gave an age of 2 728 140 ma and selected sm nd analyses an apparent isochron age of 2 825 98 ma nd 0 the pb pb age is believed to be the approximate time of emplacement interpretation of the sm nd data is complicated by the evidence of mobility of ree

a high resolution absolute dated late pleistocene monsoon record from hulu cave china oxygen isotope records of five stalagmites from hulu cave near nanjing bear a remarkable resemblance to oxygen isotope records from greenland ice cores suggesting that east asian monsoon intensity changed in concert with greenland temperature between 11 000 and 75 000 years before the present yr b p between 11 000 and 30 000 yr b p the timing of changes in the monsoon as established with 230th dates generally agrees with the timing of temperature changes from the greenland ice sheet project two gisp2 core which supports gisp2 s chronology in this interval our record links north atlantic climate with the meridional transport of heat and moisture from the warmest part of the ocean where the summer east asian monsoon originates

the greenland ice core chronology 2005 15 42 ka part 1 constructing the time scale the greenland ice core chronology 2005 gicc05 is extended back to 42 ka b2k before 2000 ad i e to the end of greenland stadial 11 the chronology is based on independent multi parameter counting of annual layers using comprehensive high resolution measurements available from the north greenland ice core project ngrip these are measurements of visual stratigraphy conductivity of the solid ice electrolytical melt water conductivity and the concentration of na c a 2 s o 4 n o 3 n h 4 a n uncertainty estimate of the time scale is obtained from identification of uncertain annual layers which are counted as 0 570 5 years the sum of the uncertain annual layers the so called maximum counting error of the presented chronology ranges from 4 in the warm interstadial periods to 7 in the cold stadials the annual accumulation rates of the stadials and interstadials are on average one third and half of the present day values respectively and the onset of the greenland interstadials 2 3 and 8 based on 20 year averaged d 18 o

linking danube river activity to alpine ice sheet fluctuations during the last glacial ca 33 17 ka bp insights into the continental signature of heinrich stadials abstract offshore archives retrieved from marine lacustrine environments receiving sediment from large river systems are valuable quaternary continental records in the present study we reconstruct the danube river activity at the end of the last glacial period based on sedimentological mineralogical and geochemical analyses performed on long piston cores from the north west black sea margin our data suggest that the danube river produced hyperpycnal floods throughout the ca 33 17 ka period four main periods of enhanced danube flood frequency each of 1 5 3 kyr duration are recorded at ca 32 5 30 5 ka equivalent to the first part of heinrich stadial hs 3 at ca 29 27 5 ka equivalent to greenland stadial 4 at ca 25 3 23 8 ka equivalent to hs 2 and at ca 22 3 19 ka based on mineralogical and geochemical data we relate these events to enhanced surface melting of the alpine ice sheet ais that covered 50 000 km2 of the danube watershed at the last glacial maximum lgm our results suggest that i the ais growth from the inner alps to its lgm position in the northern alpine foreland started from ca 30 5 ka ended no later than ca 25 3 ka and was interrupted by a melting episode ca 29 27 5 ka ii the ais volume drastically decreased from ca 22 3 to 19 ka as soon as summer insolation energy at the ais latitude increased and iii hss strongly impacted the ais mass balance through enhanced summer surface melt this together with evidence of severely cool winters and the rapid expansion of sea ice in the north atlantic implies strong seasonality in continental europe during stadials

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

lgm and late glacial fluctuations in the eastern alps abstract studies of glacier development in the eastern alps around the last glacial maximum lgm for more than a hundred years have created a reasonably well based knowledge of glacier extent sedimentation and palaeoclimate as well as chronology this was obtained from broad and detailed mapping palynological investigations and radiocarbon dating despite a very cold climate between 31 and 21 ka bp topographical constraints meant that glacier extent was limited to tributary valleys of the main trenches until about 24 ka bp then rapid ice build up in the main longitudinal valleys led to extended ice streams and to piedmont glaciers in the foreland this build up virtually ended at ca 21 ka bp according to radiocarbon dates obtained from organic matter embedded in the outwash and periglacial gravels niederterrasse the lgm possibly lasted 3000 4000 years and shows a short maximalstand and a more prolonged hochstand both connected with outwash deposits the ice decay was apparently very fast and the glaciers vanished from the longitudinal valleys probably within some hundreds of years this retreat was interrupted by two short oscillations of active glaciers in contact with huge masses of inactive ice occupying the main valley floors before these became totally ice free these events at the beginning of the oldest dryas ca 16 ka bp were followed by a distinct glacier readvance gschnitz marked by end moraines and outwash fans according to some radiocarbon dates this occurred around 14 ka bp during the bolling interstade the valleys became almost ice free the next two glacier readvances daun and egesen were limited to cirques and the higher parts of the valleys and are dated to the older and younger dryas stades respectively

the last and penultimate glaciation in the north alpine foreland new stratigraphical and chronological data from the salzach glacier abstract the northern alpine foreland was repeatedly covered by massive piedmont glaciers during quaternary glacial maxima the salzach palaeoglacier lobe austria germany was the easternmost of a series of pleistocene piedmont glaciers entering the foreland through major alpine valleys it covered an area of more than 1000 km2 during at least four glacial maxima here we aim to bring more light into its history by analyzing multiple drill log data two major outcrops topographic data and absolute chronologies of sediments stratigraphic and lithofacies investigations are focused on proximal i e near the lobe axis and distal i e near terminal moraine deposits of the salzach glacier lobe the glacial carving into the miocene bedrock occurred during early glacial maxima and was rather uniform across the lobe with larger values only in the proximal parts of the glacier more than 100 m of accumulated sediments during later glacial maxima indicate a change in ice sheet dynamics and a characteristic sequence development which varies from proximal to distal lobe positions new luminescence ages suggest a depositional focus at the penultimate glacial period while the impact of the lgm was rather minor sediments of gravelly braided rivers dominate the proximal parts of the former lobe where meltwater discharge was generally high while sheetflood deposits dominate the distal near terminal lobe positions

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

environments at the mis 3 2 transition in the northern alps and their foreland abstract this paper reviews the current state of knowledge about environmental changes at the mis 3 2 transition in the northern alps and their foreland covering the time frame from 35 to 25 ka lake and peat deposits cave sediments loess and glacial deposits are presented and the response of their biotic and abiotic proxies to climate change is discussed during late mis 3 interstadial conditions albeit weak occurred at c 36 32 ka at climatically favourable sites small patches of trees mainly pinus and some betula existed together with some shrubs the environmental conditions during late mis 3 are also reflected by a boreal brown soil horizon a cambisol called lohne soil found in many loess sequences subsequently the environmental conditions became harsher as shown by the proxy data from c 30 ka onwards the absence of pedogenesis sensu stricto and the plant assemblages point to an arctic climate in the northern alpine foreland accentuating glaciers advanced beyond the northern limit of the alps around the mis 3 2 boundary and reached their maximum extent in the foreland at about 25 ka