early eocene leptictida pantolesta creodonta carnivora and mesonychidae mammalia from the eureka sound group ellesmere island nunavut we describe the leptictid prodiacodon the pantolestids palaeosinopa sp nov cf palaeosinopa and pantolestidae gen et sp indet the creodonts palaeonictis and prolimnocyon the carnivorans viverravus cf vulpavus and miacis and the mesonychid pachyaena from early eocene i e wasatchian strata of the eureka sound group on central ellesmere island nunavut palaeosinopa and palaeonictis may have originated in mid latitude north america and subsequently migrated to europe via a north atlantic land bridge while prolimnocyon and pachyaena probably originated in asia additionally the occurrence of pachyaena in the early eocene of europe probably is best explained by dispersal from high latitude north america to europe via a north atlantic land bridge we update the eureka sound group mammalian faunal list

holocene glacier activity at the southwestern part of hardangerjokulen central southern norway evidence from lacustrine sediments lacustrine sediments from lake isdalsvatn downstream from the southwestern margin of the plateau glacier hardangerjokulen central southern norway show that the lake received glacial meltwater until 7890 95 bp a thin bluish grey minerogenic silt layer probably reflects a short glacial re advance between 7005 90 and 6835 150bp after the latter date inflow of glacial meltwater ceased indicating that small or more probably no glaciers existed on the southwestern hard angerjokulen plateau a drop in organic content and a slight increase in detrital content inferred from magnetic susceptibility at 120cm depth in the core may indicate some glacier activity in the catchment from about 3400 bp textural changes at 50cm depth indicate increased neoglacial activity in the upper catchment area from 2265 80 bp differences in glacier chronologies between the southern and northern sectors of hardangerjokulen may be explained partly by different glacier responses to the precipitation and wind distribu

scandinavian glacial and climatic fluctuations during the holocene abstract historical documents and lichenometric studies give a detailed picture of the little ice age in scandinavia there was a large advance in norway which has been dated at a few places to 1750 small readvances during the retreat occurred around a d 1780 1810 1840 1850 1850 1870 1890 1910 and 1930 in sweden most of these advances have been recognized and in addition extensive advances are dated by lichenometry to around a d 1600 1650 and 1700 1720 soils buried beneath moraines often yield radiocarbon dates that are much too old methods dependent on these must therefore be used with care evidence for pre little ice age advances are often considered equivocal the most reliable information is probably provided by studies of lacustrine sediments combining information from all sources the most significant pre little ice age glacier advances most likely occurred in 7 5 5 1 4 5 3 2 2 8 2 2 1 9 and 1 5 1 1 radiocarbon ka bp advances that were less extensive or for which there is less evidence occurred around 6300 5600 2500 940 600 560 and 380 bp

a continuous holocene glacial record inferred from proglacial lake sediments in banff national park alberta canada abstract sediment cores from three proglacial lakes in northern banff national park alberta preserve a record of holocene glacial activity upvalley which is more continuous and better dated than available surficial records dating of the cores is based on tephrochronology and 16 ams14c ages of terrestrial macrofossils all cores contain a threefold sequence of lacustrine sediments overlying a late pleistocene diamicton basal lacustrine sediments 10 10014c yr old contain little organic matter sediment composition indicates a large glacigenic contribution a sharp increase in organic content marks the beginning of the altithermal interval at all three lakes this transition occurred abruptly at about 10 10014c yr b p at crowfoot lake and possibly more gradually at the other lakes altithermal sediments contain relatively little glacigenic material and during most of the altithermal glaciers may have been absent above crowfoot and bow lakes glaciers draining into hector lake appear to have persisted through the altithermal a subsequent decrease in organic content in each lake reflecting increased clastic sedimentation marks the end of the altithermal and the onset of neoglacial ice advances the transition took place between about 5800 and 400014c yr b p and may be time transgressive beginning earlier in hector lake than in crowfoot lake changing neoglacial clastic sedimentation rates through the neoglacial interval indicate two main periods of increased glacier extent between ca 3000 and 1800 varve yr ago ca 2900 190014c yr b p and during the last several hundred years during the intervening period glaciers were less extensive but much more extensive than during the recessions of the altithermal interval

lake sediment studies of holocene glacial activity in the karsa valley northern sweden contrasts in interpretation a multidisciplinary study of lake sediments deposited in lake basins in the karsa valley northern sweden suggests the complete disappearance of the karsa glacier during the early and mid holocene glacier reformation indicated by the deposition of sediment with a fine particle size distribution and low organic content in the three lakes took place at c 3000 14 c years bp this interpretation contrasts with a study based on the weight loss on ignition of the same sediments which suggests several glacier advances throughout the entire holocene the contrasting interpretation is due to different methodological approaches single core site studies should be avoided in the future and only features that are consistently reproducible and can be dated in spatially distributed cores should be interpreted in terms of variations in glacial activity environmental conditions and ultimately climate

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

the water content of lake sediments and its relationship to other physical parameters an alpine case study the water content of lake sediment cores provides informative data for environmental reconstruction in addition to its usefulness for between core correlation significant nonlinear relationships between water content organic matter and dry density measurements suggest that high resolution records of organic matter and bulk density in alpine lake sediments can be estimated indirectly using water content as a surrogate for bulk density and organic matter data can be collected at much higher temporal scales than possible with current density samplers these results lend further credence to empirical relationships between bulk density water content and organic matter presented elsewhere

osl dating of coarse grain fluvial quartz using single aliquot protocols on sediments from ne peloponnese greece abstract optical ages of quartz extracts in holocene sediments from the north eastern peloponnese greece are reported the single aliquot regenerative dose protocol proposed by murray and wintle 2000 radiation measurements 32 57 73 was used to estimate the equivalent dose in these samples a large inter aliquot scatter in d e values was observed for all samples this is ascribed to heterogeneous bleaching of the samples at deposition to estimate a d e for age calculation a technique is suggested based on the analysis of the d e scatter obtained from nine different quartz samples which were artificially bleached and irradiated this procedure is especially useful when the sample quantity is limited the optical age estimates increase with sampling depth an average aggradation rate of 1 5 mm yr is derived using the osl ages this value is consistent with the known uplift rate of 1 2 mm yr

surface and deep ocean interactions during the cold climate event 8200 years ago evidence from a north atlantic deep sea sediment core reveals that the largest climatic perturbation in our present interglacial the 8200 year event is marked by two distinct cooling events in the subpolar north atlantic at 8490 and 8290 years ago an associated reduction in deep flow speed provides evidence of a significant change to a major downwelling limb of the atlantic meridional overturning circulation the existence of a distinct surface freshening signal during these events strongly suggests that the sequenced surface and deep ocean changes were forced by pulsed meltwater outbursts from a multistep final drainage of the proglacial lakes associated with the decaying laurentide ice sheet margin

life at the top of the greenhouse eocene world a review of the eocene flora and vertebrate fauna from canada s high arctic early middle eocene ca 53 38 ma sediments of the eureka sound group in canada s arctic archipelago preserve evidence of lush mixed conifer broadleaf rain forests inhabited at times by alligators turtles and diverse mammals including primates tapirs brontotheres and hippo like coryphodon this biota reflects a greenhouse world offering a climatic and ecologic deep time analog of a mild ice free arctic that may be our best means to predict what is in store for the future arctic if current climate change goes unchecked in our review of the early middle eocene arctic flora and vertebrate fauna we place the arctic fossil localities in historic geographic and stratigraphic context and we provide an integrated synthesis and discussion of the paleobiology and paleoecology of these eocene arctic forests and their vertebrate inhabitants the abundance and diversity of tapirs and plagiomenids both rare elements in midlatitude faunas and the absence of artiodactyls early horses and the hyopsodontid condylarth hyopsodus well represented at midlatitude localities are peculiar to the eocene arctic the eocene arctic macrofloras reveal a forested landscape analogous to the swamp cypress and broadleaf floodplain forests of the modern southeastern united states multiple climate proxies indicate a mild temperate early middle eocene arctic with winter temperatures at or just above freezing and summer temperatures of 20 c or higher and high precipitation at times this high precipitation resulted in freshwater discharge into a nearly enclosed arctic ocean basin sufficient to cause surface freshening of the arctic ocean supporting mats of the floating fern azolla fluctuating arctic ocean sea level due to freshwater inputs as well as tectonics produced temporary land bridges allowing land plants and animals to disperse between north america and both europe and asia

arcticanodon dawsonae a primitive new palaeanodont from the lower eocene of ellesmere island canadian high arctic a new genus and species of palaeanodont arcticanodon dawsonae is based on a single lower jaw fragment from lower eocene wasatchian strata of the margaret formation eureka sound group on central ellesmere island nunavut the new taxon is more derived than early paleocene escavadodontidae but lacks derived traits of metacheiromyidae it is therefore most similar to primitive epoicotheriids although the similarities are essentially in plesiomorphic features consequently arcticanodon dawsonae is classified as palaeanodonta incertae sedis pending discovery of more complete specimens resume un nouveau genre et une nouvelle espece de palaeanodonta arcticanodon dawsonae est base sur un seul fragment de mandibule inferieure provenant des strates de la formation de margaret eocene inferieur wasatchien du groupe d eureka sound au centre de l ile d ellesmere au nunavut le nouveau taxon est plus derive que escavadodontidae du paleocene precoce mais il ne presente pas les traits derives de metacheiromyidae il ressemble donc plus aux epoicotheriides primitifs bien que les similitudes se presentent surtout dans les caracteristiques plesiomorphiques par consequent arcticanodon dawsonae est classe en tant que palaeanodonta incertae sedis en attendant la decouverte de specimens plus complets traduit par la redaction rose et al 763

episodic paleoproterozoic crustal growth preserved in the aillik domain makkovik province labrador abstract the convergent margin of southeastern laurentia consists of reworked continental crust as well as accretion of continental ribbons and juvenile arc terranes forming part of the great proterozoic accretionary orogen the makkovik orogen in labrador preserves evidence of the timing duration and complexities of these accretionary events during the interval 1 88 1 78 ma new regional bedrock geological mapping combined with new u pb zircon shrimp ages constrain the paleoproterozoic felsic magmatism in the aillik group of the makkovik orogen nine samples from the aillik group yield magmatic 207pb 206pb ages between 1883 7 ma and 1858 3 ma the ages extend the previously documented ages of felsic volcanism providing evidence for periodic volcanism spanning 35 m y with the most prolific volcanic activity occurring ca 1860 ma combined with previous studies the aillik group is now constrained between 1883 7 and 1848 2 7 ma development of a pervasive planar fabric associated with the northwestward thrusting of the aillik group d3 occurred after 1848 ma lithotectonic evolution in the makkovik province comprised significant crustal reworking magmatism and minor preserved juvenile crustal growth between ca 1883 and 1848 ma the revised model for formation of the aillik group proposed herein suggests that the aillik group formed in a continental back arc setting these new ages further refine the timing of the accretionary events as well as characterizing the age of the crustal root of the arc which could be a juvenile substrate neoarchean paleoproterozoic or reworked archean crust possibly the 2 3 2 6 ma mistinibi raude crust of the southeast churchill province

probability of moraine survival in a succession of glacial advances emplacement of glacial moraines normally results in obliteration of any older moraines deposited by less extensive glacial advances a process we call obliterative overlap a probability analysis of the likely impact of obliterative overlap on the completeness of the glacial record assumes that moraines were deposited at various distances from their glacial source areas randomly over time assuming randomness and obliterative overlap after 10 glacial episodes the most likely number of surviving moraines is only three the record of the pleistocene is in agreement with the probability analysis the 10 glaciations during the past 0 9 m y inferred from the deep sea record resulted in moraine sequences in which only two or three different aged moraine belts can generally be distinguished

holocene glacier history of bjornbreen and climatic reconstruction in central jotunheimen norway based on proximal glaciofluvial stream bank mires abstract holocene variations of bjornbreen smorstabbtinden massif west central jotunheimen are reconstructed from the lithostratigraphy of two alpine stream bank mires flooded episodically by meltwater the approach uses multiple sedimentological indicators weight loss on ignition mean grain size grain size fractions bulk density moisture content and magnetic susceptibility an a priori model of overbank deposition of suspended glaciofluvial sediments a detailed chronology based on 56 radiocarbon dates and a little ice age sedimentological analogue rapid late preboreal deglaciation was indicated by immigration of betula pubescens by 9700 cal bp an interval of at least 3000 years in the early holocene when glaciers were absent was interrupted by two abrupt episodes of glacier expansion around the time of the finse event the first at ca 8270 7900 cal bp bjornbreen i event and the second at ca 7770 7540 cal bp bjornbreen ii event neoglaciation began shortly before ca 5730 cal bp with gradual build up to the maximum of the bjornbreen iii event at ca 4420 cal bp later maxima occurred at ca 2750 cal bp bjornbreen iv event and at 1300 1260 1060 and 790 cal bp all within the bjornbreen v event glaciers were smaller than today and possibly melted away on several occasions in the late holocene ca 3950 1410 and 750 cal bp minor maxima also occurred at ca 660 and 540 cal bp within the late mediaeval warm period and the early little ice age respectively the little ice age maximum was dated to 213 25 bp ca 205 cal bp the relative magnitudes of the main glacier maxima were determined erdalen event little ice age event bjornbreen vi bjornbreen i finse event bjornbreen ii bjornbreen v bjornbreen iv bjornbreen iii these episodic events of varying magnitude and abruptness were used in conjunction with an independent summer temperature proxy to reconstruct variations in equilibrium line altitude ela and a holocene record of winter precipitation since the preboreal ela varied within a range of about 390 m and winter precipitation ranged between 40 and 160 of modern values winter precipitation variations appear to have been the main cause of these century to millennial scale holocene glacier variations

early eocene rodents mammalia from the eureka sound group of ellesmere island canada rodents are a minor element in the early eocene terrestrial fauna from the eureka sound group of ellesmere island nevertheless at least five taxa can be recognized all members of the family ischyromyidae two are paramyines of which one is described as paramys hunti sp nov three of the rodents are microparamyines microparamys bayi sp nov and two species of the new genus strathcona s minor sp nov and s major sp nov the paramyines are holarctic in distribution in the early eocene but the microparamyines are known only from north america and europe the arctic microparamyinae provide the first clearly documented case for an early cenozoic mammalian taxon having a north american origin and later dispersal into europe across a north atlantic terrestrial biogeographic province

holocene fluctuations of a polythermal glacier in high alpine eastern jotunheimen central southern norway abstract bukkehammarbreen is a polythermal cirque glacier lying in the permafrost zone of eastern jotunheimen central southern norway in the proglacial lake bukkehammartjorna sediment analyses of loss on ignition loi magnetic susceptibility and analyses of grain size distribution have been used to reconstruct holocene variations in glacier activity and other catchment processes the glacier has low sediment production hence a low signal to noise ratio of minerogenic sediment flux is found grain size analyses are used to enhance the glacigenic signal and to detect glacier variations and other changes in sediment input the sedimentological record from bukkehammartjorn is compared with three other lake records from the same region in order to separate the glacial signal from variations in organic production and episodes of enhanced non glacial minerogenic sedimentation subsequent to the deglaciation after the younger dryas a preboreal glacial advance culminated before 10 100 cal bp this was followed by a prolonged period with no glaciers in the catchment until 7500 cal bp after which there is evidence of limited glacier activity lasting until 6800 cal bp between 6700 and 6000 cal bp the catchment was deglaciated after 6000 cal bp bukkehammarbreen reformed increasing in size towards 3800 cal bp with evidence for reduced glacier activity around 5200 cal bp a glacier with approximately similar size as at present has existed after 3800 cal bp the investigation has demonstrated the usefulness of multi site and multi parameter lacustrine investigations in reconstructing glacier fluctuations and for testing and validating the results the investigations have shown that grain size variations in sediment cores located at increasing distance from the meltwater inlet of a lake may provide an indicator of paraglacial activity in the catchment during the holocene the results also suggest that the lower altitudinal limit of permafrost in eastern jotunheimen remained below about 1800 m during the holocene

reconstruction of holocene glacier history from distal sources glaciofluvial stream bank mires and a glaciolacustrine sediment core near sota saeter breheimen southern norway this study attempts to reconstruct the holocene glacier history of breheimen southern norway from four stream bank mire sites and a downstream lake sediment core near sota saeter based on lithostr

lateglacial and early holocene palaeoclimatic reconstruction based on glacier fluctuations and equilibrium line altitudes at northern folgefonna hardanger western norway northern folgefonna c 23 km 2 is a nearly circular maritime ice cap located on the folgefonna peninsula in hardanger western norway by combining the position of marginal mor aines with ams radiocarbon dated glacier meltwater induced sediments in proglacial lakes draining northern folgefonna a continuous high resolution record of variations in glacier size and equili brium line altitudes elas during the lateglacial and early holocene has been obtained after the termination of the younger dryas c 11 500 cal yr bp a short lived 100 150 years climatically induced glacier readvance termed the jondal event 1 occurred within the preboreal oscillation pbo c 11 100 cal yr bp bracketed to 10 550 10 450 cal yr bp a second glacier readvance is named the jondal event 2 a third readvance occurred about 10 000 cal yr bp and corresponds with the erdalen event 1 recorded at jostedalsbreen an exponential relationship between mean solid winter precipitation and ablation season temperature at the ela of norwegian glaciers is used to reconstruct former variations in winter precipitation based on the corresponding ela and an indepen dent proxy for summer temperature compared to the present the younger dryas was much colder and drier the jondal event 1 pbo was colder and somewhat drier and the jondal event 2 was much wetter the erdalen event 1 started as rather dry and terminated as somewhat wetter varia tions in glacier magnitude elas and corresponding palaeoclimatic reconstructions at northern folge fonna suggest that low altitude cirque glaciers lowest altitude of marginal moraines 290 m in the area existed for the last time during the younger dryas these low altitude cirque glaciers of sug gested younger dryas age do not fit into the previous reconstructions of the younger dryas ice sheet in hardanger copyright 2005 john wiley sons ltd

glacier variations in breheimen southern norway dating little ice age moraine sequences at seven low altitude glaciers moraine sequences in front of seven relatively low altitude glaciers in the breheimen region of central southern norway are described and dated using a multi proxy approach to moraine stratigraphy lichenometric dating based on the rhizocarpon subgenus is used to construct a composite moraine chronology which indicates eight phases of synchronous moraine formation ad 1793 1799 1807 1813 1845 1852 1859 1862 1879 1885 1897 1898 1906 1908 and 1931 1933 although the existence of a few cases of older moraines possibly dating from earlier in the eighteenth or late in the seventeenth centuries cannot be ruled out by lichenometry schmidt hammer r values from boulders on outermost moraine ridges suggest an absence of holocene moraines older than the little ice age twenty three radiocarbon dates from buried soils and peat associated with outermost moraines at three glaciers tverreggibreen storegrovbreen and greinbreen also indicate that the little ice age glacier maximum was the neoglacial maximum at most if not all glaciers several maximum age estimates for the little ice age glacier maximum range between the fifteenth and seventeenth centuries with the youngest from a buried soil being ad 1693 a pre little ice age maximum cannot be ruled out at greinbreen however where the age of buried peat suggests the outermost moraine dates from ad 981 1399 at variance with the lichenometric evidence glaciofluvial stratigraphy at tverreggibreen provides evidence for minor glacier advances about ad 655 963 and ad 1277 1396 respectively copyright 2003 john wiley sons ltd