stratigraphic evidence for multiple holocene advances of lillooet glacier southern coast mountains british columbia holocene lateral moraines in the coast mountains of british columbia are commonly composed of multiple drift units related to several glacier advances in this paper we document lateral moraine stratigraphy at lillooet glacier in the southern coast mountains five tills separated by laterally extensive paleosols and layers of large woody debris were found in three cross sectional exposures through the northeast lateral moraine and two shallow gullies incised into its steep proximal face eighteen new radiocarbon ages constrain the timing of five separate advances of lillooet glacier 1 prior to 3000 14 c years bp 2 3000 14 c years bp 3 2500 14 c years bp 4 1700 to 1400 14 c years bp and 5 during the little ice age lia after 470 14 c years bp the lillooet glacier chronology is broadly synchronous with other glacier records from the coast mountains these records collectively demonstrate climate variability at higher frequencies during the late holocene than is apparent from many paleoecological reconstructions reconstructions of glacier fluctuations are often hampered by poor preservation of landforms that predate the extensive lia advances of the latest holocene our results highlight the potential of lateral moraine stratigraphy for reconstructing these earlier events

latest pleistocene and holocene behaviour of franklin glacier mt waddington area british columbia coast mountains canada franklin glacier is an 18 km long valley glacier that originates in a broad icefield below the west face of mt waddington in the central british columbia coast mountains canada radiocarbon dated

8000 year old wood from the athabasca glacier alberta several wood fragments of pinus sp dated at 8230 80 and 8000 90 years bp and abies sp were recovered from the snout of the athabasca glacier this wood derived from an unknown source up valley indicates that the glacier was less extensive than at present during the hypsithermal and that an area up valley of the present snout was tree covered ca 8000 8300 years bp

holocene glacier fluctuations a global overview of glacier advances and retreats grouped by regions and by millennia for the holocene is compiled from previous studies the reconstructions of glacier fluctuations are based on 1 mapping and dating moraines defined by 14 c tcn osl lichenometry and tree rings discontinuous records time series and 2 sediments from proglacial lakes and speleothems continuous records time series using 189 continuous and discontinuous time series the long term trends and centennial fluctuations of glaciers were compared to trends in the recession of northern and mountain tree lines and with orbital solar and volcanic studies to examine the likely forcing factors that drove the changes recorded a general trend of increasing glacier size from the earlyemid holocene to the late holocene in the extra tropical areas of the northern hemisphere nh is related to overall summer temperature forced by orbitally controlled insolation the glaciers in new zealand and in the tropical andes also appear to follow the orbital trend i e they were decreasing from the early holocene to the present in contrast glacier fluctuations in some monsoonal areas of asia and southern south america generally did not follow the orbital trends but fluctuated at a higher frequency possibly triggered by distinct teleconnections patterns during the neoglacial advances clustered at 4 4e4 2 ka 3 8e3 4 ka 3 3e2 8 ka 2 6 ka 2 3e2 1 ka 1 5e1 4 ka 1 2e1 0 ka 0 7e0 5 ka corresponding to general cooling periods in the north atlantic some of these episodes coincide with multidecadal periods of low solar activity but it is unclear what mechanism might link small changes in irradiance to widespread glacier fluctuations explosive volcanism may have played a role in some periods of glacier advances such as around 1 7e1 6 ka coinciding with the taupo volcanic eruption at 232 5 ce but the record of explosive volcanism is poorly known through the holocene the compilation of ages suggests that there is no single mechanism driving glacier fluctuations on a global scale multidecadal variations of solar and volcanic activity supported by positive feedbacks in the climate system may have played a critical role in holocene glaciation but further research on such linkages is needed the rate and the global character of glacier retreat in the 20th through early 21st centuries appears unusual in the context of holocene glaciation though the retreating glaciers in most parts of the northern hemisphere are still larger today than they were in the early and or mid holocene the current retreat

little ice age glacial activity in the mt waddington area british columbia coast mountains canada the establishment of fourteen little ice age lia glacier chronologies in the mt waddington area led to the development of an extended history of glacial activity in this portion of the southern british columbia coast mountains canada the glaciers were located within four different mountain ranges and were of varying size and aspect dendrochronological and lichenometric techniques were used to provide relative age estimates of moraines formed as glacier termini retreated from advanced positions evidence for pre lia glacial events is best preserved at tiedemann glacier where the oldest glacial advances date to a d 620 and 925 933 soil covered and well vegetated moraines built at cathedral pagoda and siva glaciers date to between a d 1203 and 1226 following this event moraines constructed at ragnarok siva and cathedral glaciers in the mid 14th century suggest glaciers in the region underwent a period of downwasting and retreat before readvancing the majority of moraines recorded in the mt waddington area describe late lia glacial events shown to have constructed moraines that date to a d 1443 1458 1506 1524 1562 1575 1597 1621 1657 1660 1767 1784 1821 1837 1871 1900 1915 1928 and 1942 1946 over the last 500 years these moraine building episodes were shown to occur on average every 65 years and suggest there has been prolonged synchronicity in the glaciological response to persistent climate forcing mechanisms nevertheless our analysis suggests that local factors such as aspect and size play an important role in individual glacial response notably ice termini of medium size glaciers facing eastwards showed a quicker response to climatically induced mass balance changes resume l historique de quatorze glaciers de vallee de la region du mont waddington sud de la chaine cotiere de colombie britannique canada durant le petit ge glaciaire pag fut evalue par l utilisation de techniques dendrochronologiques et lichenometriques procurant un ge minimum pour la formation des moraines laterales et frontales multiples les glaciers a l etude d aspect et de taille differents furent selectionnes a partir de quatre chaines de montagnes les evenements qui predatent le pag sont le mieux preserves sur le site du glacier tiedemann ou les plus vieilles avancees glaciaires date de a d 620 et 925 933 des moraines presentant une pedogenese avancee et recouvertes d une dense couverture vegetale furent datees entre a d 1203 et 1226 des moraines construites dans le milieu du 14 e siecle par les glaciers ragnarok siva et cathedral suggerent que les glaciers de la region se sont retires pour par la suite reavancer la majorite des moraines datees le furent vers la fin du pag soit en a d 1443 1458 1506 1524 1562 1575 1597 1621 1657 1660 1767 1784 1821 1837 1871 1900 1915 1928 et 1942 1946 au cours des 500 dernieres annees en moyenne 65 annees separent les differents episodes glaciaires ce qui suggerent un synchronisme des reponses glaciaires aux mecanismes climatiques des donnees preliminaires suggerent que l orientation et la taille des glaciers jouent un role important dans la reponse individualiste des glaciers en fait les terminus glaciaires des moyens glaciers d orientation est semblent repondre plus rapidement a un ajustement de volume interne glaciaire

neoglaciation in the southern coast mountains of british columbia chronology prior to the late neoglacial maximum moraine stratigraphy and morphology radiocarbon dates from klinaklini franklin tiedemann gilbert and bridge glaciers and related information from elsewhere in the coast mountains are used to construct a chronology for glacier fluctuations the garibaldi phase of glacier expansion 6000 5000 14c years bp at the end of the early holocene xerothermic interval is indicated by overridden tree stumps the mid neoglacial tiedemann advance 3300 1900 14c years bp is represented by moraines till and meltwater sediments at three glaciers but only tiedemann glacier attained its greatest holocene extent at this time late neoglacial expansion commenced before 900 14c years bp and continued without notable interruption until glaciers achieved their maximum post pleistocene expansion during the eighteenth and nineteenth centuries evidence for the garibaldi and tiedemann events is scarce within the coast mountains because of the more extensive late neoglacial advance however correlative advances have been

holocene climatic instability a prominent widespread event 8200 yr ago the most prominent holocene climatic event in greenland ice core proxies with approximately half the amplitude of the younger dryas occurred 8000 to 8400 yr ago this holocene event affected regions well beyond the north atlantic basin as shown by synchronous increases in windblown chemical indicators together with a significant decrease in methane widespread proxy records from the tropics to the north polar regions show a short lived cool dry or windy event of similar age the spatial pattern of terrestrial and marine changes is similar to that of the younger dryas event suggesting a role for north atlantic thermohaline circulation possible forcings identified thus far for this holocene event are small consistent with recent model results indicating high sensitivity and strong linkages in the climatic system

multi proxy record of holocene glacial history of the spearhead and fitzsimmons ranges southern coast mountains british columbia abstract evidence from glacier forefields and lakes is used to reconstruct holocene glacier fluctuations in the spearhead and fitzsimmons ranges in southwest british columbia radiocarbon ages on detrital wood and trees killed by advancing ice and changes in sediment delivery to downstream proglacial lakes indicate that glaciers expanded from minimum extents in the early holocene to their maximum extents about two to three centuries ago during the little ice age the data indicate that glaciers advanced 8630 8020 6950 6750 3580 2990 and probably 4530 4090 cal yr bp and repeatedly during the past millennium little ice age moraines dated using dendrochronology and lichenometry date to early in the 18th century and in the 1830s and 1890s limitations inherent in lacustrine and terrestrial based methods of documenting holocene glacier fluctuations are minimized by using the two records together

late holocene fluctuations of the bear river glacier northern coast ranges of british columbia canada during holocene advances of the bear river glacier in northwestern british columbia ice pushed against a bedrock slope on the north side of bear river pass as it was being diverted eastward and westward along the pass the result is a series of till sheets plastered against the rock slope and separated by wood mats this sequence of tills provides an unusually detailed record of early neoglacial history and shows that neoglacial expansion in the northern coast mountains began earlier than previously known moraines show the extent of little ice age expansion and documents related to the long mining history of the area provide records of post lia recession the oldest deposits in the area are a small lateral moraine outside of a prominent lia moraine and a till in the pass older than c 3500 14c yr bp the small moraine is undated it may be equivalent to the latest pleistocene crowfoot advance which produced similar moraines in the southern coast mountains and eastern cordillera wood mats in the pa

expansion of outlet glaciers of the juneau icefield in northwest british columbia during the past two millennia radiocarbon and dendrochronological dating of glacially overridden stumps and detrital wood indicates that two outlet glaciers of the juneau icefield advanced shortly before the little ice age tulsequah glacier advanced to within 2 4 km of its all time holocene limit between ad 865 and ad 940 llewellyn glacier one of the largest glaciers in british columbia advanced sometime between ad 300 and ad 500 and reached to within 400 m of its holocene limit between ad 1035 and ad 1210 well before the climactic classical little ice age advances of the past several centuries our data show that some glaciers in western north america were extensive and expanding at times when alpine glaciers have in the past been assumed to be restricted the evidence raises questions about how to define the time of the beginning of the little ice age and perhaps more importantly about the utility of the term

western canadian glaciers advance in concert with climate change circa 4 2 ka 1 disparate climate proxies from the northern hemisphere record a climate event at 4 2 3 8 ka here we show that glaciers throughout the mountain ranges of western canada advanced at about this time this conclusion is based on 1 new and previously reported radiocarbon ages on in situ stumps logs branches and soils exposed by recent retreat in glacier forefields and 2 clastic rich sediment intervals in cores retrieved from four montane lakes these glacier and lacustrine data indicate a period of several decades to century length when climate conditions cool summers wet winters or both favoured glacier nourishment and advance across western canada

late holocene glacial history of scimitar glacier mt waddington area british columbia coast mountains canada scimitar glacier originates below the northeast face of mt waddington in the southern british columbia coast mountains and flows 18 km down valley to calve into a proglacial lake at several locations downwasting of the glacier surface has exposed stacked till units separated by wood bearing horizons in the proximal slopes of lateral moraines flanking the glacier historical moraine collapse and erosional breaching has also revealed the remains of standing trees buried in moraine dammed lake sediments radiocarbon and tree ring dating show that scimitar glacier expanded down valley at least three times in the late holocene the earliest evidence found for ice expansion indicates scimitar glacier was advancing in 3167 2737 cal years bp in association with the regional tiedemann advance following this advance the glacier downwasted prior to expanding in 1568 1412 cal years bp during the first millennial advance a final period phase of moraine construction was initiated during late little ice age glacia

little ice age glaciers in the balkans low altitude glaciation enabled by cooler temperatures and local topoclimatic controls moraine ridges are present in the highest cirques of the durmitor massif in montenegro and post date the widespread pleistocene moraines of this area lichenometry suggests that at least eight glaciers were present in the 19th century and correlate with the culmination of the little ice age in the european alps cooler temperatures combined with local topoclimatic controls including windblown and avalanching snow as well as shading were crucial for the formation and survival of these glaciers below the regional equilibrium line altitude the resultant regional equilibrium line altitude ela was positioned close to the highest peaks between 2400 and 2500 m with local controls such as avalanche windblown snow and shading depressing the ela in the northern cirques to 2130 2210 m this ela position was very low for this latitude and lower than for most glaciers in the european alps at any time during the holocene and even equivalent to many alpine glaciers during the younger dryas today one glacier still survives in montenegro in a deep northeast facing cirque characterized by the largest combined areas of potential avalanche and windblown snow copyright 2009 john wiley sons ltd

the 8k event cause and consequences of a major holocene abrupt climate change abstract a prominent abrupt climate event about 8200 years ago brought generally cold and dry conditions to broad northern hemisphere regions especially in wintertime in response to a very large outburst flood that freshened the north atlantic changes were much larger than typical climate variability before and after the event with anomalies up to many degrees contributing to major displacement of vegetative patterns this 8k event provides a clear case of cause and effect in the paleoclimatic realm and so offers an excellent opportunity for model testing the response to north atlantic freshening has the same general anomaly pattern as observed for older events associated with abrupt climate changes following north atlantic freshening and so greatly strengthens the case that those older events also reflect north atlantic changes the north atlantic involvement in the 8k event helps in estimating limits on climate anomalies that might result in the future if warming caused ice melt and hydrologic cycle intensification at high latitudes lead to major changes in north atlantic circulation few model experiments have directly addressed the 8k event and most studies of proxy records across this event lack the time resolution to fully characterize the anomalies so much work remains to be done

neoglacial history of the stikine iskut area northern coast mountains british columbia information about neoglacial features was obtained from aerial photograph interpretation observations during low level flights ground checking and historical records terminal moraines at great flood and mud glaciers date from the late seventeenth to early eighteenth centuries and recessional moraines at these glaciers and terminal moraines at glaciers farther east date from the late nineteenth to early twentieth centuries these late neoglacial terminal moraines appear in general to mark the greatest post pleistocene extent of the glaciers radiocarbon dates from overridden trees and soil indicate that 500 600 14c years bp glaciers were considerably more extensive than they are at present and were advancing preservation of a 3800 14c year old caribou antler in a snowbank that is now rapidly shrinking suggests that climate has been relatively cool and moist for the past four millennia

on solar forcing of holocene climate evidence from scandinavia the focus of this study is the possible correlation between changes in the climate of scandinavian and changes in solar irradiation reliable information about holocene climatic change in sweden and norway is currently available from two main sources the 14c dating of pine wood retrieved from above the present pine tree limit and studies of glacier variations based on proglacial lacustrine sediments and on moraines the reconstructed alpine tree limit reveals that summer temperature in general was warmer during the early holo cene than it was during the late holocene superimposed on this general trend are several fluctuations of a few hundred years duration relatively cold periods with a duration of the order of 300 600 years occurred frequently during the holocene in this paper dates of the major climatic events are compared with an index of solar activity the so called 14c anomalies for most of the last 9000 years a good correspondence is demonstrated between the timing of cold events in scandi

altimeter observations of the bering slope current eddy field topex altimeter data is analyzed to describe the mesoscale eddy field associated with the bering slope current in the central bering sea the observed eddy field is well defined seasonally modulated and interannually variable the most energetic mesoscale eddy activity typically occurs during the spring and summer months and is characterized by a peak along isobath wavelength of 212 km and a representative wave period of 4 months spatial variability of annual period phase indicates that the axis of bering slope current exhibits seasonal offshore migration

dendrogeomorphic reconstruction of little ice age paraglacial activity in the vicinity of the homathko icefield british columbia coast mountains canada article i nfo article history moraine and glacier dams bordering the homathko icefield in the southern british columbia coast mountains failed in the 1980s and 1990s causing catastrophic downstream floods the largest of the floods occurred in august 1997 and was caused by overtopping and rapid breaching of the moraine dam that impounds queen bess lake the floodwaters from queen bess lake eroded holocene age sedimentary deposits along the west fork of nostetuko river and caused a steep rise in the hydrograph of homathko river at the head of bute inlet 115 km downstream a field investigation of the eroded valley fill in 2008 revealed multiple paraglacial valley fill units many of which are capped by in situ stumps and woody detritus dendrogeomorphological field techniques were employed to develop a chronology for the buried forests a regional tree ring chronology spanning the interval ce 1572 2007 was constructed from living subalpine fi r abies lasiocarpa trees at seven sites in the southern coast mountains in cases where subfossil stumps and boles predated the regional chronology relative death dates constrained by radiocarbon ages were assigned to floating chronologies by combining these dendrogeomorphological dating methods we identified six floodplain aggradation episodes within the past 1200 years comparison to local and regional glacial histories suggests that these events reflect climate induced little ice age changes in local glacier cover

holocene glacier fluctuations in the canadian cordillera alberta and british columbia abstract although the record of holocene glacier fluctuations in british columbia and alberta is still very fragmentary much recent progress has been made in their study dating of end moraines has been supplemented by studies of lateral moraine stratigraphy and dating of glacially overridden organic matter upstream of end moraines dates from sites close to contemporary glaciers indicate that ice had retreated to about its present limits before 10 ka bp prior to deposition of mazama tephra a minor pre hypsithermal readvance the crowfoot advance left deposits in the rockies and the interior of british columbia the earliest known neoglacial advances occurred 5 6 ka bp in the coast mountains and shortly after 4 ka bp in the rockies an advance culminating ca 4 3 ka bp has been reported from bugaboo glacier while evidence of another advance culminating in the period ca 2 5 1 8 ka bp the tiedemann advance is reported from more than one site following a recession the little ice age expansion the cavell advance began shortly after 900 bp this advance culminated in most cases in the 18th or 19th centuries the crowfoot tiedemann and little ice age advances were apparently of roughly the same magnitude the latter was most extensive in most cases but at several sites crowfoot moraines lie slightly farther downvalley than little ice age moraines during the present century ice fronts have generally retreated particularly rapidly in the period 1920 1950 a d although rates of retreat have decreased in the last three decades and some glaciers have readvanced slightly

correlation of late quaternary moraines impact of climate variability glacier response and chronological resolution abstract the last decade has seen a global surge in the number and resolution of well dated geomorphological reconstructions of mountain glacier fluctuations and former ice sheet extents this has been facilitated by the widespread deployment of large samples of terrestrial cosmogenic nuclide dating tcnd allowing more sophisticated probability analyses for reducing the statistical uncertainty of moraine ages and testing of correlations at local regional and hemispheric scales geochronological advances in the field laboratory and on model calibration have taken place in parallel with modelling of palaeoclimate based on glacier reconstructions and of glacier sensitivity to temperature and precipitation forcing in spite of these advances basic conceptual issues remain this review questions whether the technical leap forward in dating has encouraged us to over reach our interpretive limits particularly in terms of the concept and practice of correlation we propose that to enable reliable correlation glacier chronologies should first be examined for their climatic integrity spatial coherence and chronological robustness even with excellent dating interpretive complexity remains due to complex climate signals and glacier response characteristics and to erosion censoring of the landform record all are issues which must be addressed to avoid either spurious lumping correlation or splitting differentiation of glacier chronologies and thus misinterpretation of the climatic significance of reconstructed glacier advances we suggest that the reliability of correlation is no better than the weakest link in the chain of reasoning which connects climatic fluctuations with dated landforms and sediments improved dating means that poor chronological resolution is less likely to be the limiting factor for correlation but shifts the focus onto other less quantifiable sources of uncertainty these conceptual statements are exemplified with reference to holocene glacial chronologies of contrasting mid latitude environments in southern norway iceland and new zealand

evidence for a neoglacial advance of the boundary glacier banff national park alberta direct evidence for an early neoglacial advance in the canadian rocky mountains is presented radiocarbon dates from buried peat and tree remains at boundary glacier suggest limiting dates for this advance of between 3800 and 4200 years bp these data from boundary glacier are consistent with previously published dates for the onset of the neoglacial and an early neoglacial advance

the deglaciation and neoglaciation of upernavik isstrom greenland abstract we constrain the history of the greenland ice sheet margin during the holocene at upernavik isstrom a major ice stream in northwestern greenland radiocarbon dated sediment sequences from proglacial threshold lakes adjacent to the present ice margin constrain deglaciation of the sites to older than 9 6 0 1 ka this age of deglaciation is confirmed with 10 be ages of 9 9 0 1 ka from an island adjacent to the historical ice position the lake sediment sequences also constrain the ice margin to have been less extensive than it is today for the remainder of the holocene until 1100 to 700 yr ago when it advanced into two lake catchments the ice margin retreated back out of these lake catchments in the last decade the early holocene deglaciation in melville bugt one of few locations around greenland where a vast stretch of the current ice margin is marine based preceded deglaciation in most other parts of greenland earlier deglaciation in this ice sheet sector may have been caused by additional ablation mechanisms that apply to marine based ice margins furthermore despite ice sheet models depicting this sector of greenland as relatively stable throughout the holocene our data indicate a 20 km advance retreat cycle within the last millennium

latest pleistocene and holocene glacier fluctuations in western canada we summarize evidence of the latest pleistocene and holocene glacier fluctuations in the canadian cordillera our review focuses primarily on studies completed after 1988 when the first comprehensive review of such evidence was published the cordilleran ice sheet reached its maximum extent about 16 ka and then rapidly decayed some lobes of the ice sheet valley glaciers and cirque glaciers advanced one or more times between 15 and 11 ka by 11 ka or soon thereafter glacier cover in the cordillera was no more extensive than at the end of the 20th century glaciers were least extensive between 11 and 7 ka a general expansion of glaciers began as early as 8 4 ka when glaciers overrode forests in the southern coast mountains it culminated with the climactic advances of the little ice age holocene glacier expansion was not continuous but rather was punctuated by advances and retreats on a variety of timescales radiocarbon ages of wood collected from glacier forefields reveal six major periods of glacier advance 8 59 8 18 7 36 6 45 4 40 3 97 3 54 2 77 1 71 1 30 ka and the past millennium tree ring and lichenometric dating shows that glaciers began their little ice age advances as early as the 11th century and reached their maximum holocene positions during the early 18th or mid 19th century our data confirm a previously suggested pattern of episodic but successively greater holocene glacier expansion from the early holocene to the climactic advances of the little ice age presumably driven by decreasing summer insolation throughout the holocene proxy climate records indicate that glaciers advanced during the little ice age in response to cold conditions that coincided with times of sunspot minima priority research required to further advance our understanding of late pleistocene and holocene glaciation in western canada includes constraining the age of late pleistocene moraines in northern british columbia and yukon territory expanding the use of cosmogenic surface exposure dating techniques using multi proxy paleoclimate approaches and directing more of the research effort to the northern canadian cordillera

recent glacier variations and volcanic eruptions the injection of volcanic dust and gases into the atmosphere during major eruptions has been advanced to explain short term variations of climate1 4 a calculated global cooling of 1k during episodes of intense volcanic activity3 could lead to a snowline depression sufficient to cause glacier advances equivalent to those of the last several centuries the hypothesis would therefore be strengthened if a close relationship could be demonstrated between global volcanicity and the pattern of recent glacier variations glacier activity in the northern hemisphere during much of the past 100 yr shows a lack of synchrony with that in the southern hemisphere but in each hemisphere the sequence of glacier variations matches the acidity record in polar ice cores and the frequency of volcanic eruptions in successive latitude belts this suggests that glaciers fluctuate in response to atmospheric build up of volcanic aerosols produced during large eruptions and that explosive volcanism may therefore be a major factor in modulating climate on the decadal scale

holocene climate variability although the dramatic climate disruptions of the last glacial period have received considerable attention relatively little has been directed toward climate variability in the holocene 11 500 cal yr b p to the present examination of similar to50 globally distributed paleoclimate records reveals as many as six periods of significant rapid climate change during the time periods 9000 8000 6000 5000 4200 3800 3500 2500 1200 1000 and 600 150 cal yr b p most of the climate change events in these globally distributed records are characterized by polar cooling tropical aridity and major atmospheric circulation changes although in the most recent interval 600 150 cal yr b p polar cooling was accompanied by increased moisture in some parts of the tropics several intervals coincide with major disruptions of civilization illustrating the human significance of holocene climate variability c 2004 university of washington all rights reserved

pre little ice age glacier fluctuations in garibaldi provincial park coast mountains british columbia canada holocene glacier fluctuations prior to the little ice age in garibaldi provincial park in the british columbia coast mountains were reconstructed from geomorphic mapping and radiocarbon ages on 37 samples of growth position and detrital wood from glacier forefields glaciers in garibaldi park were smaller than at present in the early holocene although some evidence exists for minor short lived advances at this time the first well documented advance dates to 7700 7300 14c yr bp subsequent advances date to 6400 5100 4300 4100 2900 and 1600 1100 14c yr bp some glaciers approached their maximum holocene limits several times during the past 10 000 years periods of advance in garibaldi park are broadly synchronous with advances elsewhere in the canadian cordillera suggesting a common climatic cause the garibaldi park glacier record is also broadly synchronous with the record of holocene sunspot numbers supporting previous research that suggests solar activity may be an important climate forcing mec

tree ring derived little ice age temperature trends from the central british columbia coast mountains canada abstract most glaciers in the british columbia coast mountains reached their maximum holocene extent during the little ice age early and late little ice age intervals of expansion and retreat fluctuations describe a mass balance response to changing climates although existing dendroclimatic records provide insights into these climatic fluctuations over the last 400 yr their short durations prohibit evaluation of early little ice age climate variability to extend the duration of these records submerged coarse woody debris salvaged from a high elevation lake was cross dated to living chronologies the resulting chronology provides the opportunity to reconstruct a regional june july air temperature anomaly record extending from ad 1225 to 2010 the reconstruction shows that the intervals ad 1350 1420 1475 1550 1625 1700 and 1830 1940 characterized distinct periods of below average june july temperature followed by periods of above average temperature our reconstruction provides the first annually resolved insights into high elevation climates spanning the little ice age in this region and indicates that little ice age moraine stabilization corresponds to persistent intervals of warmer than average temperatures we conclude that coarse woody debris submerged in high elevation lakes has considerable potential for developing lengthy proxy climate records and we recommend that researchers focus attention on this largely ignored paleoclimatic archive

little ice age glacial activity in strathcona provincial park vancouver island british columbia canada dendroglaciological and lichenometric techniques are used to establish the little ice age lia history of two glaciers colonel foster and septimus in strathcona provincial park vancouver island british columbia our lichenometric investigations were preceded by the development of a locally calibrated rhizocarpon geographicum growth curve 1708 1998 a d documentation of a 3 4 year ecesis interval for both trees and lichen greatly reduces one of the main uncertainties in using geobotanical methods for dating lia landforms the moraine dates provided therefore give a good approximation of the shift in climate conditions that lead to the retreat of the glaciers and subsequent moraine stabilization geobotanical evidence records three synchronous episodes of lia moraine deposition at both glaciers two prominent moraines at each site are dated to the early 1700s and late 1800s with a third smaller moraine dated to the mid 1930s moraines deposited prior to 1397 a d were also recorded at colonel foster glacier however precise dating of these moraines was not possible the moraine records from strathcona provincial park suggest two possible modes of glacier response i synchronous responses to larger scale climatic forcing and ii asynchronous responses to local factors such as microclimate topography and glacier geometry the vancouver island lia record was evaluated in the context of lia results from the pacific north american pna cordillera it compares well with regional moraine records from coastal british columbia washington alaska and the canadian rocky mountains suggesting a regional response of pna glaciers to climate change associated with the lia

complexity of holocene climate as reconstructed from a greenland ice core glaciochemical time series developed from summit greenland indicate that the chemical composition of the atmosphere was dynamic during the holocene epoch concentrations of sea salt and terrestrial dusts increased in summit snow during the periods 0 to 600 2400 to 3100 5000 to 6100 7800 to 8800 and more than 11 300 years ago the most recent increase and also the most abrupt coincides with the little ice age these changes imply that either the north polar vortex expanded or the meridional air flow intensified during these periods and that temperatures in the mid to high northern latitudes were potentially the coldest since the younger dryas event

comparison of coupled and semicoupled numerical models for alluvial channels contrary to general statements in the literature the investigations reported in this paper show that semicoupled models are not necessarily unstable and give results comparable to those of coupled models for this purpose a two dimensional model is developed to calculate bed variations in alluvial channels vertically averaged navier stokes equations in transformed coordinates are numerically solved in conjunction with the sediment transport equation for the bed load these equations are solved simultaneously in a fully coupled model and separately in a semicoupled model using the beam and warming alternating direction implicit scheme both models are applied to predict bed level changes due to sediment overloading and sediment shut off the computed results compare satisfactorily with the experimental results obtained in a laboratory flume the results obtained by the semicoupled model are relatively close to that of the fully coupled model because the former algorithm permits any sediment formula and armoring effect to be easily incorporated the semicoupled model appears to be more attractive for general applications to real life systems than the coupled model

holocene history of the bugaboo glacier british columbia sequences of tills buried paleosols wood and tephra in moraines provide a fairly complete record of holocene fluctuations of the bugaboo glacier in british columbia the oldest till known to be exposed in the lateral moraines apparently associated with an end moraine of the regionally known crowfoot advance is overlain by mazama tephra and is possibly early holocene but probably latest pleistocene in age a paleosol incorporating the tephra and capping this till developed during early to middle holocene time it represents the warm and or dry altithermal interval subsequent neoglacial advances deposited tills after 3 39 ka but before 3 07 ka in the period ca 2 5 1 9 ka and in the period from ca 0 9 ka to the nineteenth century recessional intervals are marked by paleosols and a former moraine gully now filled results of the bugaboo glacier study increase the resolution of known neoglacial history in the canadian cordillera and generally demonstrate the usefulness of lateral moraine stratigraphy

expansion of alpine glaciers in pacific north america in the first millennium a d radiocarbon ages and lichen dated moraines from 17 glaciers in coastal and near coastal british columbia and alaska document a widespread glacier advance during the first millennium a d glaciers at several sites began advancing ca a d 200 300 based on radiocarbon dated overridden forests the advance is centered on a d 400 700 when glaciers along an 2000 km transect of the pacific north american cordillera overrode forests impounded lakes and deposited moraines the synchroneity of this glacier ad vance and inferred cooling over a large area suggest a regional climate forcing and to gether with other proxy evidence for late holocene environmental change during the me dieval warm period and little ice age provide support for millennial scale climate variability in the north pacific region

calendar dated early little ice age glacier advance at robson glacier british columbia canada dendrochronological studies at robson and bennington glaciers have provided the first calendar dating of an early little ice age glacier advance in north america dates derived from in situ stumps indicate that robson glacier began over riding forest between c ad 1142 and 1150 and continued until at least ad 1350 the highest rates of glacier advance c 3 8 m yr 1 occurred between ad 1214 and 1261 based on a series of kill dates from in situ stumps between c ad 1142 1214 and 1261 1350 rates were somewhat lower at c 2 2 5 m yr 1 this glacier advance terminated upvalley of the little ice age maximum position of robson glacier and there is no evidence at this site for glacial events between ad 1350 and 1783 however two smaller glaciers in the robson area and the main tongue of small river glacier have outermost little ice age moraines that date from the first decades of the ad 1700s all glaciers examined in the mount robson area have several well developed moraines dating from the period c

late quaternary climatic change on the american north pacific coast temporal changes in solar radiation caused by variations in the earth s orbit figure prominently in current quaternary climate theory1 4 experimental design of atmospheric circulation models emphasizes the importance of solar radiation in the heating of interglacial land and ocean surfaces at different seasons of the year whereby monsoon type circulation seasonal shifting of regional cyclonic and anticyclonic centres develops while during glacial ages seasonality is greatly modified by the influence of ice sheets5 7 we investigated the late quaternary climate of the north pacific where according to modelling solar radiation in the early holocene at the time of the summer solstice is high and in the late holocene is relatively low we compared quantitative temperature and precipitation estimates from southern alaska obtained by application of transfer functions to fossil pollen records with estimates from western washington8 and southern british columbia9 data extending over 10 000 years show a broadly consistent pattern of climatic change in general agreement with predicted variations in solar radiation and their effect on atmospheric circulation and seasonal duration of pressure systems over the north pacific ocean in the early holocene as monsoon type circulation became established with melting of glaciers the subtropical north pacific anticyclone annually regulated climate for a longer period at higher latitudes than at present so that warmth and dryness high summer radiation increased in southern alaska the aleutian low pressure centre locus of cyclonic storm activity intensified during the late holocene resulting in colder and more humid coastal climate low summer radiation over much of the year and increased frequency of glacier growth in the cordillera

the little ice age in the canadian rockies abstract this paper reviews the evidence and history of glacier fluctuations during the little ice age lia in the canadian rockies episodes of synchronous glacier advance occurred in the 12th 13th early 18th and throughout the 19th centuries regional ice cover was probably greatest in the mid 19th century although in places the early 18th century advance was more extensive glaciers have lost over 25 of their area in the 20th century selective preservation of the glacier record furnishes an incomplete chronology of events through the 14th 17th centuries in contrast varve sequences provide continuous annually resolved records of sediments for at least the last millennium in some highly glacierized catchments such records have been used to infer glacier fluctuations evaluation of recent proxy climate reconstructions derived from tree rings provides independent evidence of climate fluctuations over the last millennium most regional glacier advances follow periods of reduced summer temperatures reconstructed from tree rings particularly ca 1190 1250 1280 1340 1690s and the 1800s reconstructed periods of higher precipitation at banff alberta since 1500 are 1515 1550 1585 1610 1660 1680 and the 1880s glacier advances in the early 1700s the late 1800s and in places the 1950 1970s reflect both increased precipitation and reduced summer temperatures negative glacier mass balances from 1976 to 1995 were caused by decreased winter balances the glacier fluctuation record does not contain a simple climate signal it is a complex response to several interacting factors that operate at different timescales evaluation of climate proxies over the last millennium indicates continuous variability at several superimposed timescales dominated by decade century patterns only the 19th century shows a long interval of sustained cold summers this suggests that simplistic concepts of climate over this period should be abandoned and replaced with more realistic records based on continuous proxy data series the use of the term lia should be restricted to describing a period of extended glacier cover rather than being used to define a period with specific climate conditions

nomenclature and resolution in holocene glacial chronologies most quaternary research in canada during the first half of the twentieth century focused on pleistocene glaciation given the dramatic shifts in climate during the pleistocene it is not surprising that the holocene was viewed as a time of benign climate holocene climate variability was first recognized around the middle of the century when paleoecologists found evidence that the early part of the epoch was warmer and drier than the later part in 1970s and 1980s another generation of geologists geographers and botanists began to recognize more complexity in holocene climate and vegetation in western canada several millennial scale glacier advances postdating the early holocene warm interval were defined including the garibaldi phase 6 9 5 6 ka the tiedemann peyto advance 3 5 1 9 ka and the little ice age ad 1200 1900 subsequently application of dendrochronological techniques and stratigraphic studies in glacier forefields showed that the little ice age was itself more complex than previously thought during that 700 year period glaciers repeatedly advanced and retreated in response to climatic variability on time scales ranging from centuries to decades recent work shows that the glacier record of the garibaldi phase and the tiedemann and peyto advances are similar in complexity to the little ice age with multiple advances of glaciers separated by intervals of more restricted ice cover researchers have also identified other times in the holocene when glaciers expanded from restricted positions 8 20 4 90 3 80 and 1 70 1 40 ka continued research undoubtedly will reveal additional complexities but with what is currently known the appropriateness of terms such as tiedemann advance peyto advance and little ice age can be questioned only short periods of time separate these episodes as currently defined and it seems likely that intervals of restricted glacier cover within each of these millennial length intervals are just as long as the intervals separating them

neoglacial glacier fluctuations in the canadian rockies abstract the little ice age was the most extensive neoglacial glacier advance in the canadian rockies evidence of earlier less extensive neoglacial glacier advances is based on wood recovered from several glacier forefields wood flushed out of athabasca glacier 7550 8230 yr b p three dates and dome glacier 6120 6380 yr b p two dates indicates that forests occurred upvalley of present glacier termini during the hypsithermal detrital logs from peyto 14 dates saskatchewan 3 dates robson 3 dates and yoho 1 date glaciers plus in situ slumps at peyto and robson glaciers have yielded 14 c dates between 2490 and 3300 yr b p 12 dates between 2800 and 2990 this wood is derived from sources at or upvalley from present glacier termini and represents forests overridden by glaciers between ca 3100 and 2500 yr b p treeline was higher than present immediately prior to this advance this advance which did not extend beyond the little ice age maximum position is designated the peyto advance and correlated with the tiedemann advance in western british columbia earliest little ice age advances at peyto and robson glaciers are dated ca 800 600 yr b p at positions ca 500 m upvalley from little ice age limits

an 825 year long varve record from lillooet lake british columbia and its potential as a flood proxy abstract lillooet river in southwest british columbia has produced damaging floods many times during the past century the floods are recorded in lillooet lake into which the river flows as anomalously thick clastic varves in order to determine whether an 825 year long varve record obtained from 12 percussion and vibracores can be used as flood proxy we compare river discharge records dating back to 1914 to the thickness of the varves deposited during the same time period correlations between varve thickness and a variety of historical discharge measures are low to moderate for the periods 1914 2004 r 2 0 37 and 1914 1945 r 2 0 40 but higher for the period 1946 2004 r 2 0 55 the best correlation r 2 0 55 is between maximum fall discharge and varve thickness during the most recent period 1946 2004 varve thickness for the earlier period of hydrometric data 1914 1946 which is a time of rapid glacier retreat and warmer temperatures in british columbia is best explained with a discharge proxy combining nival runoff glacier runoff and maximum fall discharge landslides glacier fluctuations river dyking artificial lowering of lillooet lake as well as lag effects of storms are responsible for the considerable unexplained variance in the relation between discharge measures and varve thickness over the historic period the cores contain many anomalously thick varves some of which we attribute to previously dated prehistoric landslides in the watershed or to local landslides into the lake we conclude that many historic and prehistoric floods are faithfully recorded as anomalously thick clastic varves but that other processes operating in the watershed preclude using this record as a reliable paleo flood proxy

early holocene glacier advance southern coast mountains british columbia canada abstract terrestrial and lake sediment records from several sites in the southern coast mountains british columbia provide evidence for an advance of alpine glaciers during the early holocene silty intervals within organic sediments recovered from two proglacial lakes are bracketed by ams 14 c dated terrestrial macrofossils and mazama tephra to 8780 6730 and 7940 6730 14 c yr bp 10 150 7510 and 8990 7510 cal yr bp radiocarbon ages ranging from 7720 to 7380 14 c yr bp 8630 8020 cal yr bp were obtained from detrital wood in recently deglaciated forefields of sphinx and sentinel glaciers these data together with previously published data from proglacial lakes in the canadian rockies imply that glaciers in western canada advanced during the early holocene the advance coincides with the well documented 8200 yr cold event identified in climate proxy data sets in the north atlantic region and elsewhere

lateral moraine stratigraphy and neoglacial history of bugaboo glacier british columbia abstract most studies of alpine glacial history have concentrated on terminal moraines but such moraines provide dates only for maximum extents of glaciers some lateral moraines have the potential for providing more complete glacial histories because deposition by distal flank accretion may result in sequences of stacked tills interpretation is aided by 1 the approximation that any continuous surface within the moraine parallel to the moraine s distal flank is isochronous 2 inset gulley fill deposits which provide information on ice margin history and 3 incorporated organic material which can be radiocarbon dated lateral moraine stratigraphy of bugaboo glacier in southeastern british columbia suggests that the glacier was fairly close to its maximum neoglacial extent about 2500 14c yr b p a slow general expansion punctuated by at least one minor retreat continued from that time and culminated probably in the last century