palaeo moisture evolution in monsoonal central asia during the last 50 000 years abstract the late quaternary climate history of monsoonal central asia was inferred from 75 palaeoclimatic records which provide information about moisture conditions in the last 50 ka or part of this period wet conditions occurred during middle and late marine isotope stage 3 while the last glacial maximum lgm was characterized by dry climate conditions in the region a stepwise climate amelioration is suggested by the climate records following the lgm several climate signals of this period which were reported from high latitude ice core records are preserved in archives from monsoonal central asia as well during the early holocene high effective moisture was inferred from most records from the area dominated by the indian monsoon e g the tibetan plateau suggesting that holocene optimal climate conditions occurred there during this period in contrast areas which are dominated by the south east asian monsoon se monsoon and the westerlies in north western and north central china mongolia do not uniformly show an early holocene climate optimum for this area optimal conditions prevailed during the mid holocene these apparent contradictions can possibly be explained by the regional uplift and descent of air masses in the holocene during the early holocene strengthened insolation possibly caused an enhanced low level convergence over the tibetan plateau which led to the intensification of the summer monsoon the strong air uplift caused intensified precipitation and air divergence in the upper troposphere over the tibetan plateau the areas adjacent to the north therefore experienced an intensified descent of air masses and consequently increased aridity the majority of the palaeoclimatic records suggest reduced effective moisture since the late holocene in the region

quaternary glaciation of the himalayan tibetan orogen glacial geological evidence from throughout the himalayan tibetan orogen is examined to determine the timing and extent of late quaternary glaciation in this region and its relation to similar changes on a global scale the evidence summarised here supports the existence of expanded ice caps and extensive valley glacier systems throughout the region during the late quaternary however it cannot yet be determined whether the timing of the extent of maximum glaciation was synchronous throughout the entire region or whether the response was more varied the lack of organic material needed for radiocarbon dating has hindered past progress in glacial reconstruction however application of optically stimulated luminescence and terrestrial cosmogenic radionuclide methods has recently expanded the number of chronologies throughout the region limits to the precision and accuracy available with these methods and more importantly geological uncertainty imposed by processes of moraine formation and alteration both conspire to limit the time resolution on which correlations can be made to milankovitch timescales several ka in order to put all studies on a common scale well dated sites have been re evaluated and all the published terrestrial cosmogenic nuclide ages for moraine boulders and glacially eroded surfaces in the himalayan tibetan orogen have been recalculated locally detailed studies indicate that there are considerable variations in the extent of glaciation from one region to the next during a glaciation glaciers throughout monsoon influenced tibet the himalaya and the transhimalaya are likely synchronous both with climate change resulting from oscillations in the south asian monsoon and with northern hemisphere cooling cycles in contrast glaciers in pamir in the far western regions of the himalayan tibet orogen advanced asynchronously relative to the other regions that are monsoon influenced regions and appear to be mainly in phase with the northern hemisphere cooling cycles broad patterns of local and regional variability based on equilibrium line altitudes have yet to be fully assessed but have the potential to help define changes in climatic gradients over time copyright 2008 john wiley sons ltd

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

southern ocean buoyancy forcing of ocean ventilation and glacial atmospheric co2 ocean circulation and dynamics can alter atmospheric co2 concentrations numerical modelling suggests that shifts in surface buoyancy loss and the location of upwelling can sequester co2 in the southern ocean during glacial periods

modelling glacier advances and related climate conditions during the last glaciation cycle in the kuzigun valley tashkurgan catchment on the north west tibetan plateau understanding regional climate during the last glaciation cycle lgc is far from complete for the north western tibetan plateau recent improvements in understanding glacial extents and chronologies in the tashkurgan catchment north west tibetan plateau present an opportunity to estimate the glacial climatic conditions of the lgc here we use a coupled mass balance and ice flow model to reconstruct glacier advances in the kuzigun valley during the lgc and quantify the related climate conditions in the tashkurgan hangdi and kuzigun glacial stages for the region the model results show that the kuzigun valley contained ice volumes of 5 713 0 005 4 874 0 005 and 3 631 0 004 km3 with equilibrium line altitude lowering values of 500 560 and 610 m in the three successive glacial stages respectively by referencing the climatic 18o proxy records we conclude that temperature decreased by 5 8 4 and 140 modern values in the kuzigun hangdi and tashkurgan glacial stages respectively our climatic estimates for the kuzigun stage are generally consistent with previous studies that showed the last glacial maximum climate was 4 9 c colder than today on the tibetan plateau more accurate climate proxies are needed for evaluating our modelled tashkurgan climatic conditions

topographic control of thermohaline frontal structure in the barents sea polar front on the south flank of spitsbergen bank a combination of observations and process oriented numerical modeling is used to investigate the thermohaline structure of the barents sea polar front on the south flank of spitsbergen bank the polar front is the boundary between warm saline north atlantic water and cool fresh arctic water located over the outer edge of the bank observations from the barents sea polar front experiment in august 1992 show that north atlantic water was present in waters of 250 m or deeper with little vertical structure beneath the upper 50 m of the water column the mean velocity field over the south flank of the bank shows a westward flow of roughly 0 1 m s 1 in the north atlantic water and weak mean velocities over the outer edge of the bank a primitive equation model is used with idealized bathymetry to show that the inflow of north atlantic water into the barents sea via the bear island trough bifurcates at the sill between nordkapp bank and sentral bank at the eastern edge of the bear island trough one branch of the north atlantic water recirculates westward out of the barents sea and back into the norwegian sea the flow of north atlantic water is barotropic and linear following the bathymetry the recirculating branch is sheared off at the sill such that the core of recirculating flow is concentrated between the isobath coincident with the sill depth 260 m and the center of the trough 500 m both the cross bank structure of the model thermohaline fields as well as the along bank velocity are very similar to the observations at a depth of 80 m thus the frontal structure is controlled by the interaction of the barotropic inflow with the sill at the eastern edge of the bear island trough and is not controlled by processes occurring over the bank

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

characteristics of late quaternary monsoonal glaciation on the tibetan plateau and in east asia abstract glaciers fed by monsoonal precipitation are mainly located on the tibetan plateau and easternmost asia these are characterized by simultaneous accumulation and ablation in summer season the southeast part of the tibetan plateau experiences monsoonal precipitation in excess of 1000 mm yr resulting in maritime temperate glaciers in contrast precipitation in the middle and northwest part of the tibet plateau decreases from 1000 to 200 mm yr resulting in the formation of continental cold glaciers during the last glacial the regions of heavy monsoonal precipitation were restricted to the southeast corner of the plateau the westerly weak precipitation zone shifted southward and occupied the major northwest part of the plateau where the extreme continental type glaciers greatly expanded in the eastern margin of asia including taiwan central japan hokkaido and probably mount changbai maritime type glaciers were more extensive because of higher monsoonal precipitation especially heavy snowfall in northwest japan owing to the rich moisture content of the winter monsoon over the japan sea the millennial scale monsoon intensity and glacial cycle in the tibetan plateau are strongly affected by the precession cycle and the orbit inclination cycle which dominate the solar irradiance variation in low latitudes as the high radiation and strong monsoon caused the warmer and wetter climate during 40 30 ka the low radiation produced a weak monsoon and large depression of temperature and precipitation around 21 ka this climatic pattern differs from that in the high latitudes where the eccentricity cycle is prominent the temperature during the last glacial maximum lgm was 6 9 c lower than today on the tibetan plateau and the equilibrium line altitude was depressed by about 1000 m in the southeast part and in the east south and west margins of the plateau where precipitation was high the equilibrium line depression was 500 300 m in the inner and especially the west part of the plateau this variation in equilibrium lines might be caused by the combined effect of the decrease in precipitation the expansion of extreme continental glaciers and the active uplift of glaciated mountains the estimation of a glaciated area of about 350 000 km2 in the tibetan plateau and roughly 500 000 km2 in high asia based on observations of prominent features of lgm glacier extension may be the direct evidence that shows there was no quaternary unified ice sheet developed in the tibetan plateau

topography and ice sheet growth this paper uses a numerical ice sheet model to investigate the role of topography in influencing ice sheet growth the model is applied to the maritime mid latitude uplands of scotland and relies on a series of assumptions about mass balance topography and ice flow it is driven by an imposed pattern of temperature change the model is able to predict effectively the extent and thickness of the loch lomond ice sheet using a palaeotemperature curve based on coleoptera assemblages a series of experiments with a stepped constant july air temperature depression suggests that in scotland a change in excess of 3 0 c is necessary to initiate ice sheet growth that steady state ice caps build up at changes of 3 to 6 5 c and that large ice sheets build up at changes of more than 6 625 c the bifurcation revealed by the last two types of behaviour is the result of topography both the vertical amplitude and the spatial distribution of bedrock basins and ridges are important in determining the pattern rate and extent of ice sheet growth the implication is that topography plays an important role in determining the dynamics of ice sheet growth

tropical climate at the last glacial maximum inferred from glacier mass balance modeling model derived equilibrium line altitudes elas of former tropical glaciers support arguments based on other paleoclimate data for both the magnitude and spatial pattern of terrestrial cooling in the tropics at the last glacial maximum lgm relative to the present lgm elas were maintained by air temperatures that were 3 5 to 6 6 c lower and precipitation that ranged from 63 wetter in hawaii to 25 drier on mt kenya africa our results imply the need for a 3 c cooling of lgm sea surface temperatures in the western pacific warm pool sensitivity tests suggest that lgm elas could have persisted until 16 000 years before the present in the peruvian andes and on papua new guinea

late cenozoic uplift of mountain ranges and global climate change chicken or egg the high altitudes of most mountain ranges have commonly been ascribed to late cenozoic uplift without reference to when crustal thickening and other tectonic processes occurred deep incision and recent denudation of these mountain ranges abundant late cenozoic coarse sediment near them and palaeobotanical evidence for warmer climates where high mountain climates today are relatively cold have traditionally been interpreted as evidence for recent uplift an alternative cause of these phenomena is late cenozoic global climate change towards lower temperatures increased alpine glaciation a stormier climate and perturbations to humidity vegetative cover and precipitation

the role of the indian summer monsoon and the mid latitude westerlies in himalayan glaciation review and speculative discussion new dates for late quaternary glaciations in the himalayas show that during the last glacial cycle glaciations were not synchronous throughout the region rather in some areas glaciers reached their maxima at the global glacial maximum of c 18 20 ka bp whereas in others glaciers were most extensive at c 60 30 ka bp comparison of these data with palaeoclimatic records from adjacent regions suggest that on millennial timescales himalayan glacier fluctuations are controlled by variations in both the south asian monsoon and the mid latitude westerlies

equilibrium line altitudes of the last glacial maximum for the himalaya and tibet an assessment and evaluation of results abstract contemporary equilibrium line altitudes elas for glaciers in the high mountains of the himalaya and tibet have considerable variation because the region is influenced by two major climatic systems the mid latitude westerlies and the south asian summer monsoon and glaciers are subject to strong topographic controls reconstructions of past elas based on the former extent of glaciers are numerous but were estimated using a variety of methods some of which are not appropriate for high altitude glaciers which are strongly influenced by topography and have extensive supraglacial debris cover furthermore few of the reconstructions have adequate chronological control because of the difficulty of dating glacial landforms in high altitude regions where organic matter for radiocarbon dating is sparse or absent cosmogenic radionuclide surface exposure and optically stimulated luminescence dating are providing data to define the timing of glaciation and these together with objective analysis of glacier dynamics may allow better estimates of ela changes in the future however there are currently only two regions the hunza valley and the khumbu himal which are sufficiently well dated to allow reconstructions of last glacial maximum glacier extent and hence elas these two regions cannot provide an adequate assessment of ela changes for the himalayan tibetan region

timing and style of late quaternary glaciation in northeastern tibet glacial successions in the anyemaqen and nianbaoyeze mountains of northeastern tibet are reassessed and new glacial chronologies are presented for these regions cosmogenic radionuclide and optically stimulated luminescence dating indicates that two glacial advances occurred in marine isotope stage mis 3 and mis 2 in the anyemaqen mountains a third advance occurred in the early holocene we suggest that glaciation was synchronous in the anyemaqen and nianbaoyeze mountains as well as in other glaciated areas of tibet and the himalaya that are influenced by the asian monsoon the maximum extent of glaciation occurred early in the last glacial cycle mis 3 during a time of increased insolation when the monsoon intensified and supplied abundant precipitation as snow at high altitude to feed high altitude glaciers this suggests that precipitation as snow is fundamental in controlling glaciation in these regions however the occurrence of glacial advances during the insolation minimum of mis 2 suggests that despite reduced precipitation at this time the annual temperatures were cold enough to maintain positive glacier mass balances the numerically defined chronologies for the anyemaqen and nianbaoyeze mountains presented here provide a framework for comparing glacial advances in other parts of high asia

past and future mass balance of ka roimata o hine hukatere franz josef glacier new zealand despite their relatively small total ice volume mid latitude valley glaciers are expected to make a significant contribution to global sea level rise over the next century due to the sensitivity of their mass balance systems to small changes in climate here we use a degree day model to reconstruct the past century of mass balance variation at ka roimata o hine hukatere franz josef glacier new zealand and to predict how mass balance may change over the next century analysis of the relationship between temperature precipitation and mass balance indicates that temperature is a stronger control than precipitation on the mass balance of franz josef glacier the glacier s mass balance relative to its 1986 geometry has decreased at a mean annual rate of 0 02 m a 1 w e between 1894 and 2005 we compare this reduction to observations of terminus advance and retreat of which franz josef glacier has the best record in the southern hemisphere for the years 2000 05 the relative mass balance ranged from 0 75 to 1 50 m a 1 w e with 2000 01 the only year showing a negative mass balance in a regionally downscaled intergovernmental panel on climate change mean warming scenario the annual relative mass balance will continue to decrease at 0 02 m a 1 w e through the next century

beryllium 10 dating of mount everest moraines indicates a strong monsoon influence and glacial synchroneity throughout the himalaya moraine successions in glaciated valleys south of mount everest provide evidence for at least eight glacial advances during the late quaternary cosmogenic radionuclide crn surface exposure dating of moraine boulders defines the timing of each glacial advance and refines the previous glacial chronologies the crn data show that glaciation was most extensive during the early part of the last glacial marine oxygen isotype stage mis 3 and earlier but limited during mis 2 the global last glacial maximum and the holocene a previously assumed neoglacial advance is dated to 3 6 6 0 3 ka and the crn dates confirm a glacial advance ca 1 ka these results show that glaciations on the south side of everest were not synchronous with the advance of northern hemisphere ice sheets yet glaciations within the himalaya the world s highest mountain belt were synchronous during the late quaternary the existence of glacial advances during times of increased insolation suggests that enhanced moisture delivered by an active south asian summer monsoon is largely responsible for glacial advances in this part of the himalaya these data allow us to quantify the importance of global climate change and monsoon influence on glaciation in the himalaya

on estimating length fluctuations of glaciers caused by changes in climatic forcing the reaction of alpine glaciers to shifts in the equilibrium line altitude ela is calculated by using a two dimensional numerical model to solve the full equations for the velocity and stress fields full system model in the absence of basal motion rates of advance and retreat of the snout of typically sized alpine glaciers are found to be insensitive to the details of the flow at the snout even when the glaciers are far from steady state a comparison of results obtained with a full system model and a shallow ice approximation sia model yields no significant differences in advance or retreat rates this assumption has been implicitly made in numerous previous climatic studies and is here shown to be well justified using a realistic mass balance altitude feedback only slight model dependent changes in steady state lengths are found the relative importance of mass balance and glacier dynamics for the transient response of alpine glaciers to changes in the ela is given a precise meaning by determining the model dependent additional shifts in ela needed for the sia and the full system models to produce identical changes in length for alpine glaciers these additional shifts in ela are on the order of 10 m which is within the error range of ela estimates it follows that at least in the absence of significant basal motion there is no need to include the effects of horizontal stresses when calculating the reaction of alpine glaciers to climatic changes attention should focus on accurate determination of the mass balance distribution and model tuning to give realistic ice thickness distributions

modelled mass balance of xibu glacier tibetan plateau sensitivity to climate change due to a lack of in situ measurements model based studies of glacier mass balance in the tibetan plateau are very limited an energy balance model is applied to analyse the mass balance sensitivity of xibu glacier in the nyainqentanglha mountain range to climatic change a sensitivity calculation shows that a temperature change of 1 c or a precipitation change of 35 changes the equilibrium line altitude ela by 140 125 m we use a clustering method to link local weather parameters including wet season temperatures to weather types observed over the period 1955 2006 modelled variability of the xibu glacier mass balance seems to be controlled by air temperature variations during the wet season may september and by a long term warming trend that is unrelated to weather type the observed wet season temperature trend of 0 23 c 10a 1 leads to an estimated lengthening of the ablation season by 8 days at the glacier terminus 5000 m a s l and by 23 days at the ela 5590 m a s l over the period 1966 2005 the calculated rise in the ela was 49 m 10a 1

timing and climatic drivers for glaciation across semi arid western himalayan tibetan orogen abstract mapping and forty seven new 10 be ages help define the timing of glaciation in the ladakh and pangong ranges in northwest india five new local glacial stages are defined for the ladakh range from oldest to youngest these include the ladakh 4 glacial stage at 81 20 ka the ladakh 3 glacial stage not dated the ladakh 2 glacial stage at 22 3 ka the ladakh 1 glacial stage not dated and the ladakh cirque glacial stage at 1 8 0 4 ka three local glacial stages are defined for the pangong range which include the pangong 2 glacial stage at 85 15 ka the pangong 1 glacial stage at 40 3 ka and the pangong cirque glacial stage at 0 4 0 3 ka the new 10 be ages are combined with 645 recalculated 10 be ages from previous studies to develop the first regional framework of glaciation across the dryland regions of the greater himalaya transhimalaya pamir and tian shan at the western end of the himalayan tibetan orogen nineteen regional glacial stages are recognized that are termed semi arid western himalayan tibetan stages swhts these include swhts 9 at 311 32 ka swhts 7 at 234 44 ka tentative swhts 6 at 146 18 ka swhts 5e at 121 11 ka swhts 5a at 80 5 ka swhts 5a at 72 8 ka swhts 4 at 61 5 ka swhts 3 at 46 4 ka swhts 2f at 30 3 ka swhts 2e at 20 2 ka swhts 2d at 16 9 0 7 ka swhts 2c at 14 9 0 8 ka swhts 2b at 13 9 0 5 ka swhts 2a at 12 2 0 8 ka swhts 1e at 8 8 0 3 ka tentative swhts 1d at 6 9 0 2 ka tentative swhts 1c at 3 8 0 6 ka swhts 1b at 1 7 0 2 ka and swhts 1a at 0 4 0 1 ka regional glacial stages older than 21 ka are broadly correlated with strong monsoons swhts that are 21 ka or younger have smaller uncertainties and broadly correlate with global ice volume given by marine oxygen isotope stages and northern hemisphere climatic events oldest dryas older dryas younger dryas roman humid period and little ice age

a 2 d numerical model of snow ice energy balance and ice flow for paleoclimatic interpretation of glacial geomorphic features abstract standard methods of interpreting the paleoclimates recorded in alpine glacial geomorphic features rely on estimates of paleoglacier shape commonly assume that relationships between mass balance gradient and equilibrium line altitude of modern glaciers apply equally well to glaciers of in many cases dramatically different climates and do not account for the varying influence of topography on glacial extent while those methods may be adequate for many studies there are an increasing number of areas in which that level of analysis does not match the level of detail of the glacial chronologies being developed as an alternative we present a physically based 2 d glacier model that can be used to determine steady state glacier shapes and distributions for a wide range of climatic conditions the model requires only a modest amount of data beyond that which would be required for simpler methods and includes a relatively accurate representation of the effects of topography on the largest component of the surface energy balance shortwave radiation it calculates 2 d in the horizontal plane distribution of snow accumulation using a surface mass and energy balance approach and calculates the resultant glacier shapes with a 2 d flow model in addition to offering a potentially more accurate reconstruction of paleoclimatic conditions the model provides a means of performing detailed sensitivity analysis establishing relationships between similar deposits in basins of different shape and aspect and of predicting glacier shape terminus position in areas not yet explored

numerical simulations of gurenhekou glacier on the tibetan plateau we investigate the impact of climate change on gurenhekou glacier southern tibetan plateau which is representative of the tens of thousands of mountain glaciers in the region we apply a three dimensional thermomechanically coupled full stokes model to simulate the evolution of the glacier the steep and rugged bedrock geometry requires use of such a flow model we parameterize the temperature and surface mass balance smb uncertainties using nearby automatic weather and meteorological stations 6 year measured smb data and an energy balance model for a nearby glacier summer air temperature increased at 0 02 k a 1 over the past 50 years and the glacier has retreated at an average rate of 8 3 m a 1 prognostic simulations suggest an accelerated annual average retreat rate of similar to 9 1 m a 1 along the central flowline for the next 25 years under continued steady warming however regional climate models suggest a marked increase in warming rate over tibet during the 21st century and this rate causes about a 0 9 0 3 a 1 loss of glaciated area and 1 1 0 6 a 1 shrinkage of glacier volume these results the rather high warming rates predicted and the small sizes of most tibetan glaciers suggest that significant numbers of glaciers will be lost in the region during the 21st century

mid mis3 climate inferred from reconstructing the dalijia shan ice cap north eastern tibetan plateau the local last glacial maximum lgml on dalijia shan occurred during mid marine isotope stage 3 mis3 which is consistent with some tibetan plateau records but asynchronous with the mis2 global last glacial maximum lgmg paleoclimatic reconstructions are key to advancing understanding such spatial and temporal patterns of paleoglaciation using multiple methods we reconstructed mid mis3 equilibrium line altitude ela on dalijia shan and inferred temperature depressions geomorphic ela reconstructions combined with empirical data on current ela temperature and precipitation yield a mid mis3 ela of 4000 78 m a s l 618 851 m lower than current and a temperature depression of 3 3 6 8 c independent glacial modeling using the degree day approach suggests a mid mis3 ela between 3971 and 4024 m a s l and a temperature depression of 4 2 5 6 c the consistency of these results indicate that mid mis3 temperature depressions in the dalijia shan region were 3 3 6 8 c which is less than the lgmg temperature depression inferred from regional climatic proxy data combined with other proxy data this suggests that the lgml glacial advance in dalijia shan resulted from lower temperatures and slightly reduced precipitation compared with present whereas the lgmg advance was more restricted because much colder conditions were combined with much lower precipitation

climatic and topographic controls on the style and timing of late quaternary glaciation throughout tibet and the himalaya defined by 10be cosmogenic radionuclide surface exposure dating abstract temporal and spatial changes in glacier cover throughout the late quaternary in tibet and the bordering mountains are poorly defined because of the inaccessibility and vastness of the region and the lack of numerical dating to help reconstruct the timing and extent of glaciation throughout tibet and the bordering mountains we use geomorphic mapping and 10 be cosmogenic radionuclide crn surface dating in study areas in southeastern gonga shan southern karola pass and central western nyainqentanggulha shan and tanggula shan tibet and we compare these with recently determined numerical chronologies in other parts of the plateau and its borderlands each of the study regions receives its precipitation mainly during the south asian summer monsoon when it falls as snow at high altitudes gonga shan receives the most precipitation 2000 mm a 1 while near the margins of monsoon influence the karola pass receives moderate amounts of precipitation 500 600 mm a 1 and in the interior of the plateau little precipitation falls on the western nyainqentanggulha shan 300 mm a 1 and the tanggula shan 400 700 mm a 1 the higher precipitation values for the tanggula shan are due to strong orographic effects in each region at least three sets of moraines and associated landforms are preserved providing evidence for multiple glaciations the 10 be crn surface exposure dating shows that the formation of moraines in gonga shan occurred during the early mid holocene neoglacial and little ice age on the karola pass during the lateglacial early holocene and neoglacial in the nyainqentanggulha shan date during the early part of the last glacial cycle global last glacial maximum and lateglacial and on the tanggula shan during the penultimate glacial cycle and the early part of the last glacial cycle the oldest moraine succession in each of these regions varies from the early holocene gonga shan lateglacial karola pass early last glacial western nyainqentanggulha shan and penultimate glacial cycle tanggula shan we believe that the regional patterns and timing of glaciation reflect temporal and spatial variability in the south asian monsoon and in particular in regional precipitation gradients in zones of greater aridity the extent of glaciation has become increasingly restricted throughout the late quaternary leading to the preservation of old 100 ka glacial landforms in contrast in regions that are very strongly influenced by the monsoon 1600 mm a 1 the preservation potential of pre lateglacial moraine successions is generally extremely poor this is possibly because lateglacial and holocene glacial advances may have been more extensive than early glaciations and hence may have destroyed any landform or sedimentary evidence of earlier glaciations furthermore the intense denudation mainly by fluvial and mass movement processes which characterize these wetter environments results in rapid erosion and re sedimentation of glacial and associated landforms which also contributes to their poor preservation potential

modeling topographic and climatic control of east west asymmetry in sierra nevada glacier length during the last glacial maximum 1 glaciers draining westward from the sierra nevada divide california during the last glacial maximum lgm were 7 times longer than east draining glaciers we address the degree to which this difference may be attributed to the topographic asymmetry of the west tilted sierran block and the climate asymmetry resulting from orographic modification of pacific ocean storms we simulate kilometer scale glaciers within the 50 50 km kings canyon region of the southern sierra by employing a two dimensional numerical model that is driven by simple spatially variable climates and treats ice transport by deformation sliding and avalanching in numerical experiments we match simulated termini to lgm moraine positions to constrain the parameters of different climate scenarios the 38 km long lgm glacier in kings canyon was reproduced by a climate specified by an equilibrium line altitude ela of 3170 m a mass balance gradient of 0 01 m yr m and a maximum positive balance of 2 m yr this climate generates much shorter average 6 km long east draining glaciers that however overshoot the lgm moraines by 1 km roughly 97 of the e w difference in glacier lengths can therefore be attributed to topographic asymmetry alone a second experiment suggesting a 120 m higher ela of 3290 m east of the divide can explain the shorter east draining glaciers an experiment in which orographic precipitation is explicitly simulated and melt is prescribed using a positive degree day algorithm matches both kings canyon and the average east draining glacier length with an lgm climate that was 5 6 c cooler and 2 times wetter than the modern sierra nevada

last glacial maximum climate inferences from cosmogenic dating and glacier modeling of the western uinta ice field uinta mountains utah abstract during the last glacial maximum lgm the western uinta mountains of northeastern utah were occupied by the western uinta ice field cosmogenic 10 be surface exposure ages from the terminal moraine in the north fork provo valley and paired 26 al and 10 be ages from striated bedrock at bald mountain pass set limits on the timing of the local lgm moraine boulder ages suggest that ice reached its maximum extent by 17 4 0 5 ka 2 10 be and 26 al measurements on striated bedrock from bald mountain pass situated near the former center of the ice field yield a mean 26 al 10 be ratio of 5 7 0 8 and a mean exposure age of 14 0 0 5 ka which places a minimum limiting age on when the ice field melted completely we also applied a mass energy balance and ice flow model to investigate the lgm climate of the western uinta mountains results suggest that temperatures were likely 5 to 7 c cooler than present and precipitation was 2 to 3 5 times greater than modern and the western most glaciers in the range generally received more precipitation when expanding to their maximum extent than glaciers farther east this scenario is consistent with the hypothesis that precipitation in the western uintas was enhanced by pluvial lake bonneville during the last glaciation

climate during the last glacial maximum in the wasatch and southern uinta mountains inferred from glacier modeling abstract recent improvements in understanding glacial extents and chronologies in the wasatch and uinta mountains and other mountain ranges in the western u s call for a more detailed approach to using glacier reconstructions to infer paleoclimates than commonly applied aar ela at methods a coupled 2 d mass balance and ice flow numerical modeling approach developed by plummer m a phillips f m 2003 a 2 d numerical model of snow ice energy balance and ice flow for paleoclimatic interpretation of glacial geomorphic features quaternary science reviews 22 1389 1406 allows exploration of the combined effects of temperature precipitation shortwave radiation and many secondary parameters on past ice extents in alpine settings we apply this approach to the little cottonwood canyon in the wasatch mountains and the lake fork and yellowstone canyons in the south central uinta mountains results of modeling experiments indicate that the little cottonwood glacier required more precipitation during the local last glacial maximum lgm than glaciers in the uinta mountains assuming lapse rates were similar to modern model results suggest that if temperatures in the wasatch mountains and uinta mountains were 6 c to 7 c colder than modern corresponding precipitation changes were 3 to 2 modern in little cottonwood canyon and 2 to 1 modern in lake fork and yellowstone canyons greater amounts of precipitation in the little cottonwood canyon likely reflect moisture derived from the surface of lake bonneville and the lake may have also affected the mass balance of glaciers in the uinta mountains

nature and timing of quaternary glaciation in the himalayan tibetan orogen abstract much effort has been made in recent years to define the timing and extent of quaternary glaciation throughout the himalayan tibetan orogen these studies are challenging because of the logistical and political inaccessibility of the region and the inherent problems associated with the application of numerical dating techniques nevertheless the studies are providing abundant evidence for significant glacial advances throughout the last several glacial cycles and are beginning to accurately define the extent and timing of glaciation in selected regions studies are showing that himalayan tibetan glaciers in arid regions during the last glacial cycle reached their maximum extent early in the cycle and that global last glacial maximum glacier advances were significantly less extensive however along the more monsoonal influenced greater himalaya there is increasing evidence to suggest that glaciation was more extensive later in the last glacial cycle but this has yet to be fully assessed in addition the new studies are showing that throughout most himalayan tibetan regions significant glacier advances occurred during the lateglacial and early holocene with minor advances in some regions during the mid holocene the still relatively poor chronological control in the himalayan tibetan orogen however makes it difficult to construct correlations across the region and with regions elsewhere in the world this in turn makes it hard to assess the relative importance of the different climatic mechanisms that force glaciation across the himalayan tibetan orogen and to quantify paleoclimate change in this high altitude subtropical region the lateglacial and holocene glacial records however are particularly well preserved in several himalayan tibetan regions glacial successions such as these have the greatest potential to be examined in detail using newly developing numerical dating and geomorphic and sedimentologic methods to derive high resolution terrestrial records of glaciation that will help in paleoclimatic reconstruction for high altitude subtropical regions

ecological stability during the lgm and the mid holocene in the alpine steppes of tibet arid and alpine ecosystems are known for extreme environmental changes during the late quaternary we hypothesize that the world s largest alpine arid ecosystem however the alpine steppes of the tibetan highlands remained ecologically stable during the lgm and the mid holocene this hypothesis is tested by distributional range of plant species plant life forms and rate of endemism the set of character species has a precipitation gradient between 50 and 350 mm a testifying for resilience to precipitation changes 83 of the species have a wider vertical range than 1000 m used as a proxy for resilience to temperature changes 30 of the species are endemic with 10 endemic genera including plate shaped cushions as a unique plant life form these findings are in line with palaeo ecological proxies delta o 18 pollen allowing the assumption that alpine steppes persisted during the lgm with 3 to 4 k lower summer temperatures

last glacial maximum climate based on cosmogenic 10be exposure ages and glacier modeling for the head of tashkurgan valley northwest tibetan plateau abstract fully understanding the timing and climate of last glacial maximum lgm is still lack in the head of the tashkurgan valley northwest tibetan plateau tp the recent improvements in cosmogenic 10 be exposure dating and glacier modeling present an opportunity to estimate the lgm climatic conditions in the paper we investigated the moraines and used the 10 be exposure dating on the moraine boulders to constrain the timing of the lgm the kuzigun glacial stage in the head of the tashkurgan valley then we used a coupled mass balance and ice flow model to quantify the paleoclimate from past glacier extents constrained by mapped and dated kuzigun glacial moraines in the area we showed that the glaciers terminated at an elevation of 4100 4200 m asl during the kuzigun glacial stage and the glacial stage occurred during or slightly before 15 23 ka corresponding to the timing of the global lgm the modeled mass balances indicated that present day equilibrium line altitude ela ranges from 5150 to 5250 m asl and lgm ela is between 4550 and 4600 m asl in the area suggesting an ela lowering of 600 m during the lgm model results suggested that the temperature during the lgm in the head of the tashkurgan valley is 5 8 c colder than today considering a 30 70 reduction in precipitation compared to today the paleoclimate estimates are generally consistence with previous studies that showed the lgm climate was colder and drier than today on the tp

reconstruction of the 30 40 ka bp enhanced indian monsoon climate based on geological records from the tibetan plateau abstract multi proxy records from ice caps lakes and pollen records from the tibetan plateau are used to reconstruct the palaeoclimate during the period 30 40 ka bp lake geomorphological and lacustrine sedimentological studies show that numerous high lake level stands and or freshwater lakes occurred in large areas of western china at this time including over the tibetan plateau where the area contains mostly shallow water and saline hypersaline water lakes under extremely dry conditions of today pollen based reconstruction of tibetan vegetation shows systematic differences from the present alpine steppe forests were shifted ca 400 km further north and the alpine conifer forest extended ca 400 800 km beyond their present western limits variations in 18 o curves from ice cores from the plateau suggest that the temperature was 2 4 c higher and precipitation was 40 to over 100 higher than today all of the evidence consistently suggests the existence of an exceedingly strong summer monsoon climate over the plateau the vigorous evaporation of the tropical ocean surface would also play an important role in promoting the penetration of moisture rich southwest monsoon over the tibetan plateau these climate patterns with strong summer monsoon circulation during the period 30 40 ka bp reflect the 20 ka earth orbital precessional cycle when the tibetan plateau region received greater solar radiation which thus enlarged the thermodynamical contrast between the plateau and the mid south portion of the indian ocean

glacier sensitivity to equilibrium line altitude and reconstruction for the last glacial cycle glacier modeling in the payuwang valley western nyaiqentanggulha shan tibetan plateau abstract glaciers respond sensitively to climate change and paleoclimate conditions can be inferred from the geomorphic evidence by reconstructing equilibrium line altitude ela and by modeling glacier mass balance and ice flow however such work has not been extensively carried out on the vast tibetan plateau and thus the knowledge of glacier sensitivity to paleoclimate change and paleoglacier volume is still lacking on the plateau recent improvements in understanding glacial extent and chronology in the payuwang valley southern tibetan plateau present an opportunity to estimate the paleoclimate conditions during the last glacial cycle using a coupled mass balance and ice flow model this study tests the glacier sensitivity to ela change in the payuwang valley by fitting modeled glaciers to the corresponding moraine positions we reconstruct glacier extents probably occurred at oxygen isotope stage 3 mis 3 and last glacial maximum lgm in the valley and infer the related climate conditions that could have supported these glacier advances the glacier sensitivity tests indicate that in the payuwang valley the glaciers responded to centennial scale shifts in climate with elas below 5600 m asl the tributary glaciers coalesce into the main valley and expand rapidly there the model results also show that the payuwang valley contained ice volumes of 1 58 109 m3 and 1 23 109 m3 with ela lowering values of 370 m and 340 m in the mis 3 and lgm glacial advances respectively by examining other independent paleoclimatic reconstructions we conclude that during the mis 3 glacier advance the temperature was only 1 5 c lower or even 0 2 c higher than the period of 2005 2008 with precipitation 40 100 higher than the 2005 2008 amount and during the lgm glacier advance the temperature was 3 3 4 4 c lower than the period of 2005 2008 with the precipitation 30 70 lower than the 2005 2008 amount these estimates add to the knowledge of better understanding the relationship between glacier dynamic and climatic change on the tibetan plateau

persistence of full glacial conditions in the central pacific until 15 000 years ago the magnitude of atmospheric cooling during the last glacial maximum and the timing of the transition into the current interglacial period remain poorly constrained in tropical regions partly because of a lack of suitable climate records glacial moraines provide a method of reconstructing past temperatures but they are relatively rare in the tropics here we present a reconstruction of atmospheric temperatures in the central pacific during the last deglaciation on the basis of cosmogenic 3he ages of moraines and numerical modelling of the ice cap on mauna kea volcano hawaii the only highland in the central pacific on which moraines that formed during the last glacial period are preserved our reconstruction indicates that the last glacial maximum occurred between 19 000 and 16 000 years ago in this region and that temperatures at high elevations were about 7 c lower than today during this interval glacial retreat began about 16 000 years ago but temperatures were still about 6 5 c lower than today until 15 000 years ago when combined with estimates of sea surface temperatures in the central pacific ocean our reconstruction indicates that the lapse rate during the last glacial maximum was higher than at present which is consistent with the proposal that the atmosphere was drier at that time furthermore the persistence of full glacial conditions until 15 000 years ago is consistent with the relatively late and abrupt transition to warmer temperatures in greenland5 indicating that there may have been an atmospheric teleconnection between the central pacific and north atlantic regions during the last deglaciation

teleconnection of climatic events between east asia and polar high latitude areas during the last deglaciation abstract from observations of continuous aeolian and swamp sediment sequences augmented by a detailed 14 c chronology 13 c and organic c analyses we can demonstrate century to millennium scale fluctuations in east asian monsoon palaeoclimatic events we also infer significant precipitation variability within the last deglaciation the major climatic zones that have been recognised in europe and find counterparts in east asia are the bolling allerod 14 750 12 800 cal yr b p and the younger dryas 12 800 11 600 cal yr b p the last deglaciation sediment sequences are characterised by frequent facies changes reflecting climate instability these frequent abrupt climatic events correlate well with fluctuations recorded in high latitude and polar areas as represented by the greenland ice core gisp 2 and a core from the north sea this indicates a palaeoclimate teleconnection between the high latitude and polar areas and the east asian monsoon areas through cold air mass activity and the related atmospheric pressure system

cosmogenic nuclide constraints on late quaternary glacial chronology on the dalijia shan northeastern tibetan plateau abstract cosmogenic nuclide cn apparent exposure dating has become a widely used method for determining the age of glacial landforms on the tibetan plateau with 1200 published ages we present the first 10be exposure ages from the dalijia shan the most northeastern formerly glaciated mountain range on the tibetan plateau the moraine groups identified from field and remote sensing imagery mapping record four glacial events at 37 07 3 70 to 52 96 4 70 ka mis 3 20 17 1 79 to 26 99 2 47 ka mis 2 16 92 1 49 to 18 76 1 88 ka mis 2 and 11 56 1 03 to 11 89 1 06 ka younger dryas these ages indicate that glaciation in the northeastern tibetan plateau is much younger than previously thought in addition this record is consistent with many other regions on the tibetan plateau with a local last glacial maximum during mis 3 asynchronous with northern hemisphere last glacial maximum during mis 2 the dalijia shan might also include an event of younger dryas age but this needs to be tested in future studies

constraints on the late quaternary glaciations in tibet from cosmogenic exposure ages of moraine surfaces abstract this contribution provides new constraints on the timing of tibetan glacial recessions recorded by the abandonment of moraines we present cosmogenic radionuclide 10 be inventories at 17 sites in southern and western tibet 32 crests 249 samples and infer the range of permissible emplacement ages based on these analyses individual large embedded rock and boulder samples were collected from the crests of moraine surfaces and analyzed for 10 be abundance we consider two scenarios to interpret the age of glacial recession leading to the moraine surface formation from these sample exposure ages 1 erosion of the moraine surface is insignificant and so the emplacement age of the moraines is reflected by the mean sample age and 2 erosion progressively exposes large boulders with little prior exposure and so the oldest sample age records the minimum moraine emplacement age we found that depending on the scenario chosen the moraine emplacement age can vary by 50 for 100 ka old samples we consider two scaling models for estimating the production rates of 10 be in tibet which has an important although lesser effect on inferred moraine ages while the data presented herein effectively increase the database of sample exposure ages from tibet by 20 we find that uncertainties related to the interpretation of the 10 be abundance within individual samples in terms of moraine emplacement ages are sufficient to accommodate either a view in which glacial advances are associated with temperature minima or precipitation maxima that are recorded by independent paleoclimate proxies a reanalysis of published data from moraines throughout tibet shows that the variation we observe is not unique to our dataset but rather is a robust feature of the tibetan moraine age database thus when viewed in a similar way with other samples collected from this area uncertainties within moraine exposure ages obscure attribution of tibetan glacial advances to temperature minima or precipitation maxima our work suggests that more reliable chronologies of tibetan glaciations will come from improvements in production rate models for this portion of the world as well as a better understanding of the processes that form and modify these geomorphic surfaces

climates during late quaternary glacier advances glacier climate modeling in the yingpu valley eastern tibetan plateau abstract the last glacial maximum lgm featured a major cooling of earth s climate after which the climate evolved in the largest reconfiguration of the past 100 ka despite its significance full understanding of the climate history during and since the lgm is still lacking on the eastern tibetan plateau recent improvements in understanding glacial extents and chronologies in the yingpu valley eastern tibetan plateau present an opportunity to estimate the glacial climatic conditions during and since the lgm using a relatively new glacier climate model this study reconstructs glacier advances in the yingpu valley and quantifies the related climate conditions during the lgm lateglacial and late holocene glacial stages the model results show that the yingpu valley contained ice volumes of 1 65 km3 1 03 km3 and 0 29 km3 with equilibrium line altitude ela lowering values of 500 m 410 m and 150 m in the three successive glacial stages respectively by examining other independent paleoclimatic reconstructions it is concluded that the temperature decreased by 4 0 5 9 c 3 4 3 7 c 0 3 0 6 c with the precipitation amounts being 40 80 80 100 and 100 110 of modern values during the lgm lateglacial and late holocene glacial stages respectively the climate estimates for the three glacial stages are generally in agreement with other climatic proxy records on the tibetan plateau and atmospheric circulation modeling results

quaternary glaciation of muztag ata and kongur shan evidence for glacier response to rapid climate changes throughout the late glacial and holocene in westernmost tibet the glacial geology of two massifs muztag ata and kongur shan in western tibet was examined to help define the timing and style of glaciation in the semiarid regions of western tibet remote sensing geomorphic mapping and 10be terrestrial cosmogenic nuclide tcn surface exposure dating of boulders on the moraines and sediment in depth profiles show that glaciers advanced at least 12 times during at least the last two glacial cycles over this time the style of glaciation changed progressively from one that produced ice caps to one that produced less extensive and more deeply entrenched valley glaciers the timing of the two earliest glaciations is poorly defined but they likely occurred prior to the penultimate glacial cycle the karasu glacial stage and the early part of the last glacial cycle or during the penultimate glacial cycle the subaxh glacial stage in contrast the timing of later glacial advances the olimde glacial stage is relatively well defined showing quasiperiodical oscillations on millennial time scales 17 1 0 3 ka 13 7 0 5 ka 11 2 0 1 ka 10 2 0 3 ka 8 4 0 4 ka 6 7 0 2 ka 4 2 0 3 ka 3 3 0 6 ka 1 4 0 1 ka and a few hundred years before the present these data suggest that since the global last glacial maximum lgm the glaciers in western tibet likely responded to northern hemisphere climate oscillations rapid climate changes with minor influences from the south asian monsoon this study provides the first well defined glacial geologic evidence to suggest that glaciers in western tibet respond to rapid climate changes on millennial time scales throughout the late glacial and holocene

last glacial climate reconstruction by exploring glacier sensitivity to climate on the southeastern slope of the western nyaiqentanglha shan tibetan plateau improvements in understanding glacial extents and chronologies for the southeastern slope of the western nyaiqentanglha shan on the tibetan plateau are required to understand regional climate changes during the last glacial cycle a two dimensional numerical model of mass balance based on snow ice melting factors and of ice flow for mountain glaciers is used to assess the glacier sensitivity to climatic change in a catchment of the region the model can reproduce valley glaciers wide tongued glaciers and a coalescing glacier within step temperature lowering and precipitation increasing experiments the model sensitivity experiments also indicate that the dependence of glacier growth on temperature and or precipitation is nonlinear the model results suggest that the valley glaciers respond more sensitively to an imposed climate change than wide tongued and coalescing glaciers guided by field geological evidence of former glacier extent and other independent paleoclimate reconstructions the model is also used to constrain the most realistic multi year mean temperatures to be 2 9 4 6 degrees c and 1 8 2 5 degrees c lower than present in the glacial stages of the last glacial maximum and middle marine oxygen isotope stage 3 respectively

mechanisms forcing abrupt fluctuations of the indian ocean summer monsoon during the last deglaciation abstract a piston core from the somali upwelling area has been studied at high resolution for its dinoflagellate cyst content variations in cyst association are inferred to reflect changes in indian ocean summer monsoon intensity several abrupt fluctuations in monsoon intensity are detected for the interval between 20 and 10 ka bp comparison of these fluctuations with changes in contrast between 30 n and 30 s july insolation and the 18 o grip ice core values suggests that different mechanisms influenced monsoon intensity at different time intervals a general trend in monsoon intensity follows variations in insolation contrast lagging minimum contrast by 7 5 ka and maximum contrast by 4 ka this phase lag difference can be explained by assuming the existence of an ice snow cover over central asia tibet during glacial times between 18 7 and 12 5 ka bp fluctuations in sw monsoon intensity may be forced by variations in the thermohaline ocean circulation a rapid transition towards strong sw monsoons at 12 5 ka bp is possibly the result of variations in atmospheric circulation and melting of the snow ice fields in central asia tibet variations in glacial interglacial boundary conditions related to temperature change at northern latitudes are likely to have influenced sw monsoon intensity between 12 5 and 10 ka bp whereas after 10 ka bp variations in tropical land surface boundary conditions may be the dominant forcing factor 0 1997 elsevier science ltd all rights reserved

correlation between climate events in the north atlantic and china during the last glaciation episodes of massive iceberg release heinrich events 1 3 into the north atlantic ocean during the last glaciation were associated with recurring episodes of unusually cold north atlantic surface water bond cycles 4 and cold air temperatures over greenland dansgaard oeschger events 5 6 four of the youngest of these cold events have also been reported in climate records from sites outside the north atlantic region7 but until now the entire suite has been identified only in north atlantic marine sediments greenland ice core records and tentatively in french lake sediments8 here we examine grain size data from chinese loess and intercalated accretionary palaeosols of last glacial age for evidence of similar climate signals remote from the north atlantic region we see grain size maxima with ages that match those of the last six heinrich events which we interpret as an indication of the changing strength of the east asian winter monsoon which largely controls the transport and deposition of central asian aeolian dust thus it seems that these heinrich events have left their signature in the chinese loess record this is consistent with simulations of the glacial climate9 which imply that the climates of the north atlantic and china were linked by the effect of westerly winds

timing and climatic drivers for glaciation across monsoon influenced regions of the himalayan tibetan orogen abstract mapping and thirty eight 10 be terrestrial cosmogenic nuclide tcn ages help define the timing of glaciation in the monsoon influenced greater himalaya in central garwhal india glacial landforms in central garwhal are present only within a few kilometers of the present glaciers and all date to less than 12 5 ka this suggests that the lateglacial and or holocene glacial advances were more extensive than their predecessors and hence destroyed or buried evidence for earlier glaciation or that other processes such as intensive fluvial erosion and or hillslope mass movements have destroyed evidence of earlier glaciation prominent laterofrontal moraines date to the lateglacial the early holocene and the neoglaciation moraines next to the active ice and boulders on contemporary glaciers date to 10 1 10 2 years before present this suggests only a minor glacial advance during the little ice age occurred in central garhwal these young ages indicate that inheritance of tcns in areas that were recently glaciated is very small and likely has little effect when considering tcn ages on moraines older than the global last glacial maximum the new 10 be ages are combined with 1081 recalculated 10 be ages from previous studies to develop a regional framework of glaciation across the monsoon influenced and adjacent regions of the himalayan tibetan orogen we separate what appears to be continuous glaciation into 27 regional glacial stages plus 2 tentative glacial stages that are termed monsoonal himalayan tibetan stages mohits the regional glacial stages cover a wide chronologic range that includes five regional glacial stages older than the last glacial cycle mohits 13 at 483 38 ka to mohits 5e at 122 15 ka thirteen regional glacial stages within the last glacial cycle mohits 5b at 91 15 ka to mohits 2a at 12 9 0 9 ka and eleven regional glacial stages during the holocene mohits 1k at 11 4 0 7 ka to mohits 1a at 0 4 0 1 ka there are strong correlations both with periods of strong monsoons and northern hemisphere events throughout the entire chronologic range with 16 stages linked to the monsoon 11 stages linked to the mid latitude westerlies and two unassigned because of large age uncertainties overall we see a complex pattern of glaciation influenced by two climatic systems throughout the mid late quaternary