relict non glacial surfaces in formerly glaciated landscapes abstract relict non glacial surfaces occur within many formerly glaciated landscapes and contain important information on past surface processes and long term landscape evolution relict non glacial surfaces are distinguishable from glacial surfaces by large scale morphologies including rounded summits fluvial valleys and cryoplanation terraces and pediments and the presence of tors blockfields and or saprolites preservation during glaciation occurs either through coverage by non erosive cold based ice or as nunataks although surface morphologies and denudation rates indicate a continuous non glacial surface history since preglacial times relict non glacial surfaces are dynamic features that have evolved during the quaternary depending on spatial variables such as lithology slope regolith depth and the abundance of fine matrix and water some surfaces are denuding very slowly while others display more rapid denudation high spatial variability in denudation rates results in changing surface morphologies over time denudation rates also display high temporal variability with much surface evolution having perhaps occurred soon after the initial onset of glaciation or during paraglacial phases while some parts of non glacial landscapes are currently active others may be largely inactive relicts of past higher energy regimes although non glacial surfaces are dynamic much remains to be determined regarding surface denudation rates and the magnitude of morphological changes over time

an evaluation of lohmann s foraminifera weight dissolution index down water column traverses of core top weights for three planktonic species confirm lohmann s 1995 relationship between foraminifera shell weight loss and bottom water carbonate ion content however they also suggest that the initial shell thickness varies with growth habitat and that the offset between bottom water and pore water carbonate ion concentration varies even on small space scales

mis 3 to mis 1 temporal and lgm spatial variability in arctic ocean sea ice cover reconstruction from biomarkers using the sea ice proxy ip25 and phytoplankton derived biomarkers brassicasterol and dinosterol arctic sea ice conditions were reconstructed for marine isotope stage mis 3 to 1 with special emphasis on the last glacial maximum lgm in sediment cores from the northern barents sea continental margin across the central arctic ocean to the southern mendeleev ridge our results suggest more extensive sea ice cover than present day during latter part of mis 3 increasing sea ice growth during mis 2 and decreased sea ice cover during the last deglacial the summer ice edge remained north of the barents sea even during extremely cold i e last glacial maximum lgm as well as warm periods i e bolling allerod during the lgm the western svalbard margin and the northern barents sea margin areas were characterized by high concentrations of both ip25 and phytoplankton biomarkers interpreted as a productive ice edge situation caused by the inflow of warm atlantic water in contrast the lgm central arctic ocean north of 84 n was covered by thick permanent sea ice throughout the year with rare break up indicated by zero or near zero biomarker concentrations the spring summer sea ice margin significantly extended southwards to the laptev sea shelf southern lomonosov ridge and southern mendeleev ridge during the lgm our proxy reconstructions are very consistent with published model results based on the north atlantic arctic ocean sea ice model naosim

climate and oceanographic variability in the sw barents sea during the holocene the holocene section of the marine sediment core psh 5159n located in the sw barents sea has been studied at high resolution with a multiproxy approach a well stratified water column occurred at the site 11 9 8 ka bp the stratification was probably a result of a winter sea ice cover and or fresh warm surface waters during summer stratification and resultant reduction in air sea interaction allowed for warmer bottom water temperatures the general situation 11 9 8 ka bp could have been associated with an anomalous high pressure system over the nordic seas and the arctic ocean during the 11 10 5 ka bp interval the polar front was located close to the barents sea margin the polar front moved towards the site from 10 5 ka bp and from 9 8 to 7 5 ka bp it was probably located close to the site at 7 5 ka bp the polar front retreated eastwards as the present day oceanographic pattern established the mid holocene was in general characterized by rather stable conditions in contrast highly variable cond

paleoceanography of the barents sea during the holocene 1 we measured the oxygen isotopic composition of planktonic and benthic foraminifera in three cores collected at key positions to reconstruct the paleoceanography of the barents sea core asv 880 on the path of the northern branch of atlantic water inflowing from the arctic ocean core asv 1200 in the central basin near the polar front and core asv 1157 in the main area of brine formation modern seawater 18o measurements show that far from the coast 18o variations are linearly linked to the salinity changes associated with sea ice melting the foraminifer 18o records are dated by 14c measurements performed on mollusk shells and they provide a detailed reconstruction of the paleoceanographic evolution of the barents sea during the holocene four main steps were recognized the terminal phase of the deglaciation with melting of the main glaciers which were located on the surrounding continent and islands the short thermal optimum from 7 8 ka b p to 6 8 ka b p a cold mid holocene phase with a large reduction of the inflow of atlantic water and the inception of the modern hydrological pattern by 4 7 ka b p brine water formation was active during the whole holocene the paleoclimatic evolution of the barents sea was driven by both high latitude summer insolation and the intensity of the atlantic water inflow

contrasting environmental memories in relict soils on different parent rocks in the south western italian alps abstract soils on the alps are usually weakly developed both because of the extensive pleistocene glaciations and because of slope steepness and climate enhancing erosion however on some stable relict surfaces particularly in the outermost sections of the alpine range some highly developed soils are apparently in contrast with holocene soil forming conditions in this work we assess the extent of pedogenesis in some of these soils located under montane level vegetation in the ligurian alps sw piemonte italy and relate it to the effects of climate and parent material the considered well developed profiles showed signs of extremely different pedogenetic processes on the different lithotypes in particular podzols with extremely thick e horizons up to more than 2 m thick and very hard thick ortstein or placic horizons were formed on quartzite reddish terra rossa luvisols were formed on limestone red extremely acidic alisols were formed on shales the chemical properties the micromorphology and the clay mineralogy demonstrated high intensity pedogenic trends and were characteristic of processes usually occurring under different climates they may therefore represent excellent pedo signatures of different specific past climatic environmental conditions as a response of different lithologies to specific soil forming environments which range from warm and humid climates typical of red alisols and luvisols to cool and humid wet climates leading to the formation of podzols with ortstein placic horizons

liquid and plastic limits of clayey organic c rich mountain soils role of organic matter and mineralogy abstract the soil liquid ll and plastic limit pl and their difference pi plasticity index are physical properties related with the soil mechanical behavior determined on the

evaluation of the sea ice proxy ip25 against observational and diatom proxy data in the sw labrador sea the recent rapid decline in arctic sea ice cover has increased the need to improve the accuracy of the sea ice component in climate models and to provide detailed long term sea ice concentration records which are only available via proxy data recently the highly branched isoprenoid ip25 identified in marine sediments underlying seasonal sea ice has emerged as a potential sea ice specific proxy for past sea ice cover we tested the reliability of this biomarker as a sea ice proxy against observational sea ice data sea ice concentrations from the global hadisst1 database and against a more established sea ice proxy sea ice diatom abundance in sediments in the south west sw labrador sea furthermore our study location at the southern margin of arctic sea ice drift provided a new environmental setting in which to further test the novel pip25 index our two study sites are located north east ne and south east se of newfoundland where box cores covering the last ca 100 150 years were collected ip25 concentrations are nearly an order of magnitude higher and sea ice diatoms more abundant in sediments from ne of newfoundland where sea ice prevails 2 4 months per year compared to the sediments se of newfoundland where conditions are generally ice free year round the ip25 fluxes ne of newfoundland agree well with multi decadal north atlantic oscillation nao trends in the study area which in previous studies have been shown to affect the climatic and sea ice conditions in the region when assessed against observational sea ice data ip25 appears to be a more sensitive indicator of sea ice variability in this setting compared to sea ice diatoms and proved to be a robust and reliable proxy for reconstructing low frequency variability in past sea ice concentrations the pip25 index results clearly differ from the observed sea ice data underlining that caution needs to be exercised when using the index in different environmental settings

late quaternary paleochemistry of high latitude surface waters recent studies have stressed the role of high latitude nutrient levels and productivity in controlling the carbon isotopic composition of the deep sea and the co2 content of the atmosphere we undertook a study of the chemical composition of the polar planktonic foraminifer neogloboquadrina pachyderma s sinistral coiling from 30 late holocene samples and 49 down core records from the high latitude north and south atlantic oceans to evaluate the history of sea surface chemical change from glacial to interglacial time stable isotopic analysis of coretop samples from the atlantic pacific and southern oceans shows no significant correlation between the 13c of n pachyderma and either 13c or po4 in seawater conversely cd ca ratios in planktonic foraminifera are consistent with the po4 content of surface waters the level of maximum glaciation 18 000 yr b p identified by climap and 18o was chosen for mapping isopleths of 18o on n pachyderma s in the north atlantic reveal a pattern largely influenced by sea surface temperature s s t and generally support the s s t reconstruction of climap differences between the two suggest significantly lower salinity in north atlantic surface waters at high latitudes than in lower latitudes down core 13c records of n pachyderma confirm that low 13c values occurred in the northeast atlantic during the latest glacial maximum labeyrie and duplessy 1985 however a map of 13c for the 18 000 yr b p level for a much larger region in the north atlantic shows that minimum n pachyderma 13c occurred in temperate waters n pachyderma 13c decreased toward the southwest reaching a minimum of 1 at 37 n despite the variability seen in 13c records of n pachyderma none of our cores show significant temporal variability in cd ca from the combined cd ca and 13c data we can see no evidence for an upwelling gyre in the eastern north atlantic during the latest glacial maximum nor evidence that the southern and northern oceans had significantly different levels of preformed nutrients than today

oxygen isotope composition of living neogloboquadrina pachyderma sin in the arctic ocean data from the nansen basin of the arctic ocean are used to investigate the habitat and conditions under which the polar planktic foraminifer neogloboquadrina pachyderma sin calcifies the vertical distribution of 18o values of net sampled speciments together with their abundances and proportion of calcification are compared with 18o values from both water samples and foraminiferal tests from core top sediments within the nansen basin the average depth of habitat of n pachyderma sin changes from about 150 m in the southern part to about 80 m in the northern the average depth of calcification however in both regimes varies between 100 and 200 m water depth 18o data from net sampled n pachyderma sin are directly reflected in the core top sediment data but compared to equilibrium calcite 18o values derived from measurements of the ambient water a consistent offset of about 1 over all depth intervals is observed while in the southern part of the nansen basin advection through fram strait of planktic foraminifers from further south may play a role the data from the northern part of the nansen basin give clear evidence that the observed offset in 18o values is caused by a vital effect of n pachyderma sin

carbonate preservation records of the past 3 myr in the norwegian greenland sea and the northern north atlantic implications for the history of nadw production carbonate preservation records from a number of drill sites in the north atlantic and adjacent norwegian greenland sea ngs are used to reconstruct variations in north atlantic deep water nadw production over the past 3 myr before the initiation of major northern hemisphere glaciation good carbonate preservation was recorded in the north atlantic and the ngs supporting the superconveyor model of accelerated nadw formation in the late pliocene after the inception of main northern hemisphere glaciation nadw formation in the ngs was blocked off during the period 2 8 1 9 ma carbonate was only badly preserved due to 1 low production of carbonate shells in surface waters 2 sluggish renewal of deep waters induced by a rather stable sea ice cover and or 3 production of carbonate corrosive dense brines during sea ice formation e g sea ice dissolution mode in contrast contemporaneous good preservation in the adjacent north atlantic indicates efficient nadw production during the middle matuyama 1 9 1 4 ma the first intrusions of the proto norwegian current into a narrow corridor in the southeastern ngs are evidenced by much better carbonate preservation a decrease both in carbonate content and preservation towards the north and west of this corridor indicates the proximity of the polar front and gives evidence that nadw production was efficiently triggered by the atlantic water entrainment mode during the past 1 2 myr carbonate preservation patterns in the ngs clearly reflect major global events like the mid pleistocene transition and the mid brunhes dissolution event the onset of the mid pleistocene transition at 1 2 ma is characterized by a complete shift to higher carbonate contents in the southeastern ngs and labrador sea overall good preservation during both interglacials and glacials is only interrupted by high frequency short term dissolution spikes which were induced by ice sheet collapse and development of extensive meltwater lids as a consequence nadw was produced nearly continuously during glacials in the nordic seas however due to its lower density it was entrained into intermediate water levels in the north atlantic and thus enforced the intermediate water circulation loop whereas a decrease in lower nadw production is observed contemporaneously

identification of contrasting seasonal sea ice conditions during the younger dryas abstract a palaeo sea ice reconstruction for northern norway for the interval ca 13 8 7 2 cal ka bp has been performed using a combined organic geochemical proxy based study of a marine sediment core jm99 1200 obtained from andfjorden 69 15 95 n 16 25 09 e and the outcomes compared with a series of other palaeoclimate studies carried out previously within this study particular emphasis has been placed on the identification of the sea ice conditions during the younger dryas and the application of different biomarker based proxies to both identify and quantify seasonal sea ice conditions firstly the appearance of the specific sea ice diatom proxy ip 25 at ca 12 9 cal ka bp in the sedimentary record has provided an unambiguous but qualitative measure of seasonal sea ice and thus the onset of the younger dryas stadial the near continuous occurrence of ip 25 for the next ca 1400 yr demonstrates seasonal sea ice during this interval although variable abundances suggest that the recurrent conditions in the early mid younger dryas ca 12 9 11 9 cal ka bp changed significantly from stable to highly variable sea ice conditions at ca 11 9 cal ka bp and this instability in sea ice prevailed for the subsequent ca 400 yr during which an extremely short interval of permanent or near permanent sea ice was observed at ca 11 75 cal ka bp at ca 11 5 cal ka bp ip 25 disappeared from the record indicating ice free conditions that signified the beginning of the holocene the ip 25 concentrations were also combined with those of the open water phytoplankton biomarker brassicasterol to generate p b ip 25 data from which more quantitative measurements of sea ice were determined p b ip 25 data were consistent with consecutively seasonal then infrequent sea ice cover for the early mid and late younger dryas while further comparisons of the p b ip 25 data with the outcomes of previous correlations with modelled sea ice concentrations suggested that these intervals were characterised by ca 60 90 and ca 0 60 sea ice cover respectively both qualitative and quantitative sea ice records were also consistent with sea surface temperature and other palaeoclimate estimates derived previously from various other proxy studies the contrasting seasonal sea ice conditions during the younger dryas were further verified through a comparison of the concentrations of ip 25 with those of another highly branched isoprenoid hbi alkene that is di unsaturated and believed to also be produced by sea ice diatoms the ratio of the hbi diene to ip 25 termed dip 25 is believed to provide a useful indicator of stability or variability in sea ice conditions and complements the outcomes from the ip 25 and p b ip 25 index data the identification of contrasting seasonal sea ice conditions during the younger dryas will likely contribute to the debate regarding the climatic impacts that took place during this intriguing interval

pleistocene periglacial imprinting on polygenetic soils and paleosols in the sw italian alps abstract because of extensive pleistocenic glaciations which erased most of the previously existing soils slope steepness and climatic conditions favoring soil erosion most soils observed in the alps and in other mid latitude mountain ranges have developed during the holocene or late glacial period however in few sites particularly in the outermost sections of the alpine range pleistocene glaciers covered only small and scattered surfaces and ancient soils could be preserved for long periods on stable surfaces in many cases these soils retain good memories of quaternary periglacial activity which have never been characterized on the alpine range based on both geomorphological and pedological interpretations this work aims to investigate these environments providing therefore new evidences to support paleoclimate reconstructions on the alps we described and sampled soils on stable surfaces in the upper tanaro valley ligurian alps southwestern piemonte italy the sampling sites were between 600 and 1600 m a s l under present day lower montane ostrya carpinifolia montane fagus sylvatica forests or montane heath grazed grassland on quartz rich substrata the surface morphology often showed strongly developed fossil periglacial morphologies such as large scale patterned ground blockfields blockstreams or solifluction sheets the soils preserved in such quaternary periglacial landforms normally showed stratification of different layers units separated by structural discontinuities evidencing different depositional settings and different pedogenic development degree a strong cryogenic granulometric sorting characterized all the observed soils paleosols with silt enriched horizons and lateral differentiation of sand and stone rich parts and fine enriched ones organic matter was irregularly distributed at depth as a result of past cryoturbation compact and dense layers with strong platy lenticular structural aggregation wedge casts and large scale cryoturbations were described below fixed depths in all soil profiles thus surface morphology and soil properties suggest the presence of permafrost during cold pleistocene phases with two main active layer thicknesses at 60 120 and 100 160 cm depths respectively

sea ice variations in the central canadian arctic archipelago during the holocene abstract a sea ice record for barrow strait in the canadian arctic archipelago caa is presented for the interval 10 0 0 4 cal kyr bp this holocene record is based primarily on the occurrence of a sea ice biomarker chemical ip25 isolated from a marine sediment core obtained from barrow strait in 2005 a core chronology is based on 14c ams dating of mollusc shells obtained from ten horizons within the core the primary ip25 data are compared with complementary proxy data obtained from analysis of other organic biomarkers stable isotope composition of bulk organic matter benthic foraminifera particle size distributions and ratios of inorganic elements the combined proxy data show that the palaeo sea ice record can be grouped according to four intervals and these can be contextualised further with respect to the holocene thermal maximum htm spring sea ice occurrence was lowest during the early mid holocene 10 0 6 0 cal kyr bp and this was followed by a second phase 6 0 4 0 cal kyr bp where spring sea ice occurrence showed a small increase between 4 0 and 3 0 cal kyr bp spring sea ice occurrence increased abruptly to above the median and we associate this interval with the termination of the htm elevated spring sea ice occurrences continued from 3 0 to 0 4 cal kyr bp although they were more variable on shorter timescales within this fourth interval we also provide evidence for slightly lower and subsequently higher spring sea ice occurrence during the mediaeval warm period and the little ice age respectively comparisons are made between our proxy data with those obtained from other palaeo climate and sea ice studies for the caa

semi quantitative reconstruction of early to late holocene spring and summer sea ice conditions in the northern barents sea semi quantitative estimates of early to late holocene spring sea ice concentration spsic and occurrence of summer sea ice for the northern barents sea have been obtained by analysing the biomarkers ip25 brassicasterol and a tri unsaturated highly branched isoprenoid lipid in a holocene marine sediment core sub surface water mass variations were derived from planktic foraminiferal assemblages and stable isotopes 18o 13c the record indicates paleoceanographic changes over three intervals during period i ca 9500 5900 cal a bp the study location experienced the lowest recorded spsic ca 25 with short spring seasons and long productive summers resulting partly from increased atlantic water inflow that caused a stronger ocean atmosphere heat exchange throughout period ii ca 5900 2700 cal a bp the winter sea ice margin migrated southwards and an overall cooling trend resulted in higher spsic ca 60 and increased delivery of cold arctic water during period iii ca 2700 cal a bp to present spsic increased further ca 75 and some sea ice remained during summer months a sub surface warming probably indicates a decoupling of heat exchange between the ocean and the atmosphere longer springs and shorter summers were accompanied by the most southerly location of the winter sea ice margin

marine 14c reservoir ages for 19th century whales and molluscs from the north atlantic abstract in order to compare radiocarbon dates on marine and terrestrial samples the former have to be corrected for a reservoir age we present reservoir ages from dating 21 whales collected 1860 1901 and recalculating dates of 23 molluscs collected 1857 1926 most of the whales were caught along the coast of norway but one is from france and one from iceland we assume the former mainly lived in the north and equatorial atlantic and in the norwegian sea whales feed only on pelagic organisms and will provide the reservoir age for the open ocean surface water however they travel long distances and will integrate the reservoir ages of the different water masses along their way molluscs dated from norway spitsbergen and arctic canada are stationary and monitor the sea water passing their dwelling site but some also take up carbon from particulate food or sediment pore water coastal water also often contains some continental carbon we present two different views on how to analyze and interpret the data mangerud recommends to use reservoir ages based on a combination of the whale and mollusc dates i e 380 30 and 360 30 yr relative to intcal04 and british oak respectively and a r value of 20 30 for the surface water in the n atlantic and norwegian sea bondevik and gulliksen maintain that the reservoir age and r along the norwegian coast is latitude dependant with r values increasing from 3 22 in the south to 105 24 at spitsbergen whales reflecting north atlantic open ocean surface water have lower r 7 11 than most molluscs

carbon isotope composition of tropical surface water during the past 22 000 years carbon isotope values of many species of planktonic foraminifera are size dependant values of 13c of individual size fractions are therefore an integration of low 13c values of calcite precipitated in the juvenile growth stage and high values precipitated in later stages in general the selection of a particular size fraction for downcore studies has been subjective analysis of different size fractions of planktonic foraminifera however yields different time series in downcore studies by measuring the 13c of many size fractions the 13c precipitated throughout the growth of the foraminifera can be calculated time series of the 13c of calcite precipitated in the late growth stages of planktonic foraminifera from two nearby cores from the caribbean sea result in a better correlation than time series of constant size fractions these 13c records indicate similar 13c values during the last glaciation and the late holocene and a broad deglacial minimum approximately synchronous with a minimum in the 13c records of benthic foraminifera from intermediate depth atlantic cores the deglacial minimum may be a reflection of the isotopic composition of the underlying intermediate water which may be affected by circulation changes or changes in preformed 13c values and or of the flux of water upwelled into the surface layer the small 0 2 to 0 0 glacial interglacial 13c difference in tropical surface water is also believed to be affected by the chemistry of the underlying source water

branching of atlantic water within the greenland spitsbergen passage an estimate of recirculation atlantic water aw supplies the largest source of heat mass and salt to the arctic ocean via fram strait greenland spitsbergen passage yet it represents only a fraction of the atlantic water that resides in the greenland iceland norwegian and barents seas this is a result of both the branching of the central core of aw along its northward flow and the modification of its t s signature through air sea ice interactions and internal mixing this paper addresses the quantitative analysis of the three dominant atlantic water cores within fram strait and north of 76 n using an 11 year 1977 to 1987 hydrographic database spatial variations of heat volume and salt along its flow path of some 600 km showed that the major core of atlantic water that directly enters the arctic ocean svalbard branch did not extend past 20 e of the 9719 km3 of atlantic water existing within the region one third resided within the svalbard branch the remainder 22 and 45 were held within the return atlantic current and the yermak branches respectively restricting the analysis to a southern limit of 79 n effectively removed the return atlantic current and showed a nearly equal split between the two remaining branches work completed by bourke et al 1988 indicated that the yermak branch is largely recirculated to the south if true this analysis supports rudels 1987 model estimate of a 50 recirculation of aw within this region

the gin sea a synthesis of its physical oceanography and literature review 1972 1985 abstract a synthesis and review of the physical oceanography of the gin sea greenland iceland and norwegian seas is presented an accompanying bibliography is included from 1972 through 1985 some 1986 works are also noted emphasis is placed on describing the gin sea as a major semi enclosed basin that plays a role unique among the world s oceans by providing a strong two way advective exchange between the ice covered polar sea and the north atlantic ocean and at the same time acting as the primary site for northern hemisphere bottom water formation the water masses for the gin sea are defined in a manner as consistent as possible with the literature the large scale oceanographic and meteorological factors influencing the water mass formation and circulation are described a sample calculation of the various horizontal and vertical thermohaline driven exchanges is given

the arctic sea ice biomarker ip25 a review of current understanding recommendations for future research and applications in palaeo sea ice reconstructions in recent years a novel proxy for the past occurrence of arctic sea ice has been proposed that is based on the variable marine sedimentary abundance of an organic geochemical lipid derived from sea ice diatoms in the spring this lipid termed ip25 ice proxy with 25 carbon atoms is a highly branched isoprenoid mono unsaturated alkene that appears to be sufficiently stable in sediments to permit meaningful palaeo sea ice reconstructions to be carried out over short to long term timescales since the first proposed use of ip25 as a proxy for palaeo sea ice by belt et al 2007 a number of laboratories have measured this biomarker in arctic sediments and it is anticipated that research activity in this area will increase further in the future the content of this review is divided into a number of sections firstly we describe the scientific basis for the ip25 proxy and its initial discovery in arctic sea ice sedimenting particles and sediments secondly we summarise the relatively few studies that have to date concentrated on examining the factors that influence the production and fate of ip25 and we identify some areas of future research that need to be addressed in order to improve our understanding of ip25 data obtained from sedimentary analyses what is clear at this stage however it that the presence of ip25 in arctic marine sediments appears to represent a proxy measure of past seasonal sea ice rather than permanent or multi year ice conditions thirdly we highlight the importance of rigorous analytical identification and quantification of ip25 especially if measurements of this biomarker are going to be used for quantitative sea ice reconstructions rather than qualitative analyses alone presence absence fourthly we review some recent attempts to make the interpretations of ip25 biomarker data more detailed and quantitative by combining sedimentary abundances with those of phytoplankton and other sea ice derived biomarkers thus the bases for the so called pip25 and dip25 indices are described together with an overview of potential limitations concluding that investigations into the use of these indices needs further research before their full potential can be realised in the final section we provide a summary of ip25 based palaeo sea ice reconstruction case studies performed to date these case studies cover different arctic regions and timescales spanning decades to tens of thousands of years

stable oxygen and carbon isotopes in planktic foraminifers from arctic ocean surface sediments reflection of the low salinity surface water layer planktic foraminifers neogloboquadrina pachyderma sin from 87 eastern and central arctic ocean surface sediment samples were analyzed for stable oxygen and carbon isotope composition additional results from 52 stations were taken from the literature the lateral distribution of 18o full size image 33 atlantic waters entering the arctic ocean through the fram strait 18o values decrease both to the barents shelf and to the north pole in accordance with the decreasing salinities of the halocline waters in the nansen basin a strong n s 18o gradient is in contrast with a relatively low salinity change and suggests contributions from different freshwater sources i e salinity reduction from sea ice meltwater in the south and from light isotope waters meteoric precipitation and river runoff in the northern part of the basin north of the gakkel ridge 18o and salinity gradients are in good accordance and suggest less influence of sea ice melting processes the 13c full size image 1 k values of n pachyderma sin from arctic ocean surface sediment samples are generally high 0 75 0 95 lower values in the southern eurasian basin appear to be related to the intrusion of atlantic waters the high 13c values are evidence for well ventilated surface waters because the perennial arctic sea ice cover largely prevents atmosphere ocean gas exchange ventilation on the seasonally open shelves must be of major importance lack of 13c gradients along the main routes of the ice drift from the siberian shelves to the fram strait suggests that primary production i e co2 consumption does probably not change the co2 budget of the arctic ocean significantly

paleoceanography of the last interglacial glacial cycle in the polar north atlantic abstract using to its position close to the sites of waxing and waning of the major northern hemisphere ice sheets during the late quaternary climatic cycles the polar north atlantic plays a key role in driving global change therefore analyzing the present day sedimentation processes and reconstructing the late quaternary paleoceanography in this region has been a focus of major scientific interest through the last fifteen years this paper aims to combine the vast amount of new results about modern sediment fluxes surface sediment distribution and the paleoceanographic record and to present a comprehensive overview of the paleoceanography in the polar north atlantic through the last 200 000 years which is based on the basinwide analysis of carbonate and ice rafted detritus records during the last fifteen years the climap paleoceanographic view of the glacial polar north atlantic as an almost permanently isolated sea covered by heavy sea ice throughout the year has been shifted to a much more dynamic view of the environmental conditions a meridional current system similar to the present day conditions secured the exchange of water ice and heat between the polar north atlantic and the alantic and arctic oceans although affected by variations in strength and intensity this meridional current pattern resulted in an almost permanent presence of at least some seasonally ice free areas with all the consequences for e g marine life and deep water formation in addition the development of the continental ice sheets namely the fennoscandian and the barents sea ice sheets is closely related to this dynamic circulation pattern during the so called nordway events the pronounced inflow of temperate waters from the south provided moisture for the growth of the ice sheets the most prominent of these events stage 6 stage 4 and substage 3 1 2 ended in major glaciations reflected in the terrestrial sequences and in the deep sea ird records

marine calcium carbonate preservation vs climate change over the last two millennia in the fram strait implications for planktic foraminiferal paleostudies abstract we present a high resolution study of planktic foraminiferal distribution patterns in a deep sea core from the eastern fram strait position 78 55 n 06 46 e water depth 1497 m the sediment core is located below atlantic water masses flowing into the arctic ocean and spans the last 2400 years the investigation is based on planktic foraminiferal species distribution stable isotopes and sedimentological data the mean shell weight of neogloboquadrina pachyderma fragmentation organic and inorganic carbon content and the presence of benthic organic linings were also investigated as an indication of preservation changes the results indicate that the planktic foraminifera are affected by dissolution and point to five periods of especially poor preservation at 200 bce 300 650 ce 700 850 ce 1400 1500 ce and from 1800 ce to present in the last century small and fragile subpolar species turborotalita quinqueloba and globigerinita uvula are preserved the increased percentage of these subpolar species together with increases in the caco 3 toc and total foraminiferal flux would point to surface water warming however our data suggest that these fragile species may not have been preserved in sediments older than 1900 ce due to selective dissolution consequently the magnitude of the previously recorded recent surface water warming in the fram strait may be overestimated

recent calcium carbonate dissolution in the barents sea paleoceanographic applications abstract studies of benthic foraminifera in surface sediments of the arctic epicontinental barents sea show several indications of calcium carbonate dissolution low values of calcium carbonate correspond to low ratios of calcareous agglutinating foraminifera planktic benthic foraminifera high ratios of living dead foraminifera corroded calcareous foraminifera and high numbers of exposed organic linings of foraminifera dissolution increases eastwards and northwards in the study area we suggest that the dissolution is caused by the presence of dense cold saline and co 2 rich bottom water which is linked to sea ice production and the position of the oceanic polar front we also think calcium carbonate dissolution in this area indicates a sink for atmospheric co 2

paired δ18o signals of neogloboquadrina pachyderma s and turborotalita quinqueloba show thermal stratification structure in nordic seas abstract the vertical density gradients in the nordic seas are crucial for the preconditioning of the surface water to thermohaline sinking in winter these gradients can be reconstructed from paired oxygen isotope data in tests of different species of planktonic foraminifera the isotopic signatures of which represent different calcification depths in the water column comparison of 18 o values from foraminiferal tests in plankton hauls sediment traps and nearby core top samples with the calculated 18 o calcite profile of the water column revealed species specific 18 o vital effects and the role of bioturbational admixture of subfossil specimens into the surface sediment on the basis of core top samples obtained along a west east transect across various hydrographic regions of the nordic seas 18 o values of turborotalita quinqueloba document apparent calcification depths within the pycnocline at 25 75 m water depth the isotopic signatures of neogloboquadrina pachyderma s reflect water masses near and well below the pycnocline between 70 and 250 m off norway where the atlantic inflow leads to thermal stratification here temperatures in the calcification depth of n pachyderma s differ from sea surface temperature by approximately 2 5 c in contrast n pachyderma s calcifies very close to the sea surface 20 50 m in the arctic domain of the western nordic seas however further west n pachyderma s prefers somewhat deeper more saline water at 70 130 m well below the halocline that confines the low saline east greenland current this implies that the 18 o values of n pachyderma s do not fully reflect the freshwater proportion in surface water and that any reconstruction of past meltwater plumes based on 18 o is too conservative because it overestimates sea surface salinity minimum 18 o differences n pachyderma s and t quinqueloba may serve as proxy for sea regions with dominant haline and absent thermal stratification whereas thermal stratification leads to 18 o differences of 0 4 to 1 5

pedogenesis in the sorted patterned ground of devon plateau devon island nunavut canada abstract in the high arctic the barren expanses of devon plateau devon island are affected by intense frost action that conditions geomorphic processes at the landscape level soil formation at the profile level and the establishment and distribution of vascular plants at microsites in the high arctic in areas of patterned ground frost action is responsible for both the accumulation of parent material through the segregation of fines in features here called islands of fines and for the development of soil profiles through cryoturbation in these features at the landscape level segregation of fines results in the development of patterned ground specifically in the formation of sorted stripes sorted circles and plugs that repeat themselves on the landscape plugs consist of cylindrical to conical soil masses protruding from the frost permafrost table in the stony areas that may coalesce to form island of fines cryoturbation the dominant soil forming process is manifested by the appearance of convoluted horizons injection of material up heaving of stones and soil mixing but there are also non cryoturbated soils with a b c vertical sequences we have described sampled and analyzed the soils simultaneously present in the islands of fines also we have examined the plugs the stony areas and the stony borders non cryoturbated soils typic haplorthels or brunosolic eutric static cryosols occurred at the edges of the sorted circles once the injection of heaved material has subsided they showed an a horizon grayish brown relatively rich in carbon and nitrogen sandier than the underlying b horizon which is characterized by the presence of illuvial silt caps the c horizon is low in organic carbon and nitrogen and poorly rooted despite wet conditions and impeded drainage because of the high ph low organic matter content and low biological activity oxidation reduction processes are not well expressed c horizon material injected from the frost permafrost table penetrated into the body of the island of fines rupturing horizons and merging at the surface these soils are aquic haploturbels or gleysolic turbic cryosols the major soil forming processes that are acting in the haplorthels or brunosolic cryosols include brunification lessivage and decarbonation carbonation in the aquic haploturbels or gleysolic turbic cryosols the processes are cryoturbation gleying and decarbonation carbonation stony areas play the important role of trapping air born dust that includes mineral and organic components also autochthonous living organisms dwell in these block fields the air born mineral fines together with those left by the receding ice cap and those produced by weathering aliment the formation of plugs islands of fines and the sorted stripes

fossil cryogenic features in paleosols of southern italy characteristics and paleoclimatic significance the work presents the results of a study of two paleosols located at 1350 m a s l on the sila massif in southern italy the purpose of this research is to examine paleoenvironmental conditions during the last glaciation based mainly on soil morphological micromorphological and sedimentological data these two paleosols contain climatically sensitive cryogenic features including a sand wedge an ice wedge cast silt veins silt lenses reticulate silt veins and matrix lenses these features are interpreted to indicate that during the last glacial maximum this area in southern italy experienced conditions characterized by very low temperature little snow cover and great aridity

quantifying carbonate dissolution and calibration of foraminiferal dissolution indices in the somali basin two sediment traps moored off somalia in 1992 1993 collected similar settling fluxes of carbonate and siliceous shells formed by various plankton groups planktic foraminifera showed large seasonal variations with more than 74 of the total planktic foraminifera flux collected during the sw monsoon summer upwelling when globigerina bulloides was dominating along with globigerinita glutinata and neogloboquadrina dutertrei the intermonsoon and ne monsoon assemblages were dominated by globigerinoides ruber we used the trap records as our no dissolution reference for comparison with three boxcore recorders in order to quantify the carbonate dissolution along a depth transect dissolution increases downslope from station 905 to 907 and 915 at depths of 1567 m 2807 m and 4035 m respectively the carbonate fraction of the sediment at station 915 which is located near the ccd is the most affected by dissolution with more than 97 of the planktic foraminifera dissolved here the planktic foraminifera assemblage is strongly modified with thick walled species such as n dutertrei globorotalia tumida and pulleniatina obliquiloculata as the most resistant it is not representative of the settling assemblage the planktic foraminiferal assemblages of the sediment surface at stations 905 and 907 remain similar to the trap assemblages and the foraminifera are well preserved although only 25 of foraminifera are apparently preserved at station 905 and 8 at station 907 those numbers are surprisingly low and infer that only a small fraction of the foraminiferal carbonate production is buried and removed from the carbon cycle this discrepancy between the export and buried flux is partly be due to bio mechanical destruction by benthic processes and to supralysoclinal dissolution due to metabolic co2 generated by the benthic organisms another important factor is the interannual variability of the productivity well known in the arabian sea the calibration of commonly used foraminiferal dissolution indices percentage of foraminiferal fragments percentage of resistant species foraminiferal dissolution index fdx to our data only shows reliable results for high dissolution levels 97 off somalia the most accurate of the proxies is the percentage of foraminiferal fragments compared to the other methods tested i e fdx planktic foraminiferal loss l percentage of radiolarians and diatoms percentage of benthic foraminifera the species assemblage appears to be not significantly modified by dissolution unless the estimated shell loss is high 92 of the arriving shells in our samples this level is expressed in the percentage of fragmentation the percentage of radiolarians and diatoms the percentage of resistant foraminifera species and fdx as 80 35 25 and 1 8 respectively the relative abundance of globigerina bulloides is a valid sw monsoon upwelling proxy only when dissolution is moderate 92 globigerina bulloides and globigerinoides ruber have similar burial efficiencies and susceptibilities to dissolution thus the ratio g bulloides g ruber is a valid proxy for past changes in the intensity of the sw monsoon even in the strongly dissolved samples in our sediment record the ratio g bulloides g ruber indicates that the sw monsoon was stronger in the recent past than in 1992 93

distribution of planktic foraminifera at the ice margin in the arctic fram strait planktic foraminifera were collected in net tows 63 m along two east west transects at 78 and 80 n in the fram strait northern nordic seas at five concurrent depth intervals in the upper 200 m of the water column in the ice free zone absolute abundances in the upper 200 m of the water column up to 500 individuals m3 were obtained along the ice margin the absolute abundances reached up to 1250 ind m3 while in the ice covered areas not more than 50 ind m3 have been found surprisingly these strong variations in abundance are not accompanied by significant changes in faunal assemblages between the ice free and the ice covered regions neogloboquadrina pachyderma is the dominant species in most samples making up to 60 of the total faunal assemblage globigerina quinqueloba contributes 38 and all other species combined make up only 2 of the total fauna both absolute and relative abundances of the collected foraminifera are strongly dependent on the mesh size used using smaller mesh sizes provides a wider species spectrum which is of special interest for paleoceanographic reconstructions in the nordic seas where fossil assemblages 150 m often consist of only one species the specific hydrographic conditions in the fram strait with warm atlantic waters underlying cold polar surface waters result in a rather atypical depth distribution of the planktic foraminifera all species seem to prefer the temperate atlantic waters between 50 m and 200 m thus the species composition as well as geochemical tracers do not reflect the surface ocean conditions which again has potentially interesting implications for paleoceanographic reconstructions

periglacial cover beds on the swiss plateau indicators of soil climate and landscape evolution during the late quaternary abstract soils and the stratification of their parent materials were studied on the central swiss plateau this area is characterized by glacial deposits varying from late glacial to pre wurmian in age soils of all studied sites are developed within colluvial layers the so called cover beds in relation to the underlying deposits we find a regular spatial distribution of cover bed types a surficial layer upper layer with relatively constant thickness around 50 cm independent of relief position covers pleistocene sediments of any age therefore it was formed mainly by cryoturbation solifluction after the final glacier retreat from the swiss plateau younger dryas or oldest dryas age layers that originate mainly from aeolian processes intermediate layers are restricted to areas outside the recessional moraines of the berne stade bs hence they were formed merely up to the late pleniglacial they frequently consist of two distinct layers outside the glaciation of the last glacial maximum lgm cover beds in places overlie pre lgm palaeosol relics probably of eemian age or even older these are preserved even on higher relief positions indicating that periglacial erosion during the pleniglacial was only marginal the palaeosol relics also occur on till of the so called older wangen stade which is commonly believed to represent the lgm whereas we consider it to be older at least partly eventually the distribution of soil types and their ecological characteristics are influenced considerably by cover beds as these beds reflect distinct phases of the pleistocene colluvial sediments provide a major tool for linking modern landscape characteristics to the late quaternary climate evolution

delineation of potential exploration targets based on 3d geological modeling a case study from the laoangou pb zn ag polymetallic ore deposit china abstract the laoangou pb zn ag polymetallic ore deposit lag is a hydrothermal vein type deposit in the east qinling polymetallic metallogenic belt which is controlled by nw ne and nearly sn trending faults and mainly hosted in the dolomite marble of meiyaogou and baishugou formations within the luanchuan ore district lod although district scale metallogenic prediction related to the pb zn ag deposits in the lod has been attempted there have been no studies to formulate a detailed deposit scale metallogenic prediction of the pb zn ag deposit in 3d space here we selected the lag to formulate a metallogenic prediction model for pb zn ag deposit based on data from 1 10 000 scale geological map and 66 boreholes and 39 sections of exploration lines on 1 1000 scale to extract the salient spatial features of the deposit we apply ordinary weights and weighted weights of evidence followed by boosted weights of evidence logistic regression and information entropy for integrating the features of the ore deposit for exploration targeting the c v fractal method is applied to classify the probabilities accordingly three levels of exploration targets are delineated the first level targets are mainly distributed in the periphery of known orebodies m2 m3 ii 3 and vi which are also located in the ore controlling strata and fault zones the second level targets are located in the region of known orebodies indirectly confirming that the prediction result is reliable and the third level targets which are mainly located at the contact between ore controlling strata and metagabbro bodies offer new targets for exploration in this ore district combining our results obtained in this study with those in previous studies we provide some guidelines for exploration targets in the pb zn ag deposits in the lod which might help in more effectively delineating the target zones

climate and environmental changes recognized by micromorphology in paleolithic deposits at arene candide liguria italy abstract the lowermost part of the stratigraphic sequence of the arene candide cave a key upper palaeolithic site in italy attests to significant climate and environmental change at the beginning of the late pleniglacial in coastal liguria northwest italy these archaeological layers were studied using a suite of mineralogical and chemical technique including a contextual sedimentological analysis micromorphology this study shows that the lower layers are dominated by cryoclastic sediments covered by cyclically organized blackish and reddish layers or lenses the black layers mainly consist of bird and bat guano deposits interfingered with thin brownish sandy silt layers of aeolian origin that contain large amount of ca phosphate in contrast the bright red layers are rubified sediment due to fe re oxidizing in insoluble form in these layers evidence of syngenetic freeze thaw cycles associated with gelifluction processes indicates a cool episode in a semi arid periglacial environment coupled to an increase in humidity between ca 31 and 27 ka cal bp subsequently the occurrence of features associated with repeated runoff and debris flow processes that caused a significant accumulation of poorly layered and sorted materials in the overlying sediments indicates a further intensification of humid conditions and reflects a longer phase of more humid and temperate climate this change from arid to semiarid humid climates resulted in an increase in sediments resulting from the erosion of pliocene marine terraces and soils located outside the cave the identification in the studied sequence of guano layers and the scarcity of artefacts in conjunction with an absence of clear cultural micromorphological evidence support an interpretation of sporadic human occupation of this part of the cave during middle upper palaeolithic gravettian therefore the finding in such a context of the lavish ceremonial burial of the so called young prince may suggest that the cave was used as a special place for burials at that time

identification of paleo arctic winter sea ice limits and the marginal ice zone optimised biomarker based reconstructions of late quaternary arctic sea ice abstract analysis of 100 surface sediments from across the barents sea has shown that the relative abundances of the mono unsaturated sea ice diatom derived biomarker ip 25 and a tri unsaturated highly branched isoprenoid hbi lipid hbi iii are characteristic of the overlying surface oceanographic conditions most notably the location of the seasonal sea ice edge thus while ip 25 is generally limited to locations experiencing seasonal sea ice with higher abundances found for locations with longer periods of ice cover hbi iii is found in sediments from all sampling locations but is significantly enhanced in sediments within the vicinity of the retreating sea ice edge or marginal ice zone miz the response of hbi iii to this well defined sea ice scenario also appears to be more selective than that of the more generic phytoplankton biomarker brassicasterol the potential for the combined analysis of ip 25 and hbi iii to provide more detailed assessments of past sea ice conditions than ip 25 alone has been investigated by quantifying both biomarkers in three marine downcore records from locations with contrasting modern sea ice settings for sediment cores from the western barents sea intermittent seasonal sea ice and the northern norwegian sea ice free high ip 25 and low hbi iii during the younger dryas ca 12 9 11 9 cal kyr bp is consistent with extensive sea cover with relatively short periods of ice free conditions resulting from late summer retreat towards the end of the yd ca 11 9 11 5 cal kyr bp a general amelioration of conditions resulted in a near winter maximum ice edge scenario for both locations although this was somewhat variable and the eventual transition to predominantly ice free conditions was later for the western barents sea site ca 9 9 cal kyr bp compared to nw norway ca 11 5 cal kyr bp for both locations coeval elevated hbi iii but absent ip 25 potentially provides further evidence for increased atlantic water inflow during the early holocene but this interpretation requires further investigation in contrast ip 25 and hbi iii data obtained from a core from the northern barents sea demonstrate that seasonal sea ice prevailed throughout the holocene but with a gradual shift from winter ice edge conditions during the early holocene to more sustained ice cover in the neoglacial a directional shift that has undergone a reverse in the last ca 150 yr according to observational records our combined surface and downcore datasets suggest that combined analysis of ip 25 and hbi iii can provide information on temporal variations in the position of the maximum winter arctic sea ice extent together with insights into sea ice seasonality by characterisation of the miz combining ip 25 with hbi iii in the form of the previously proposed pip 25 index yields similar outcomes to those obtained using brassicasterol as the phytoplankton marker importantly however some problems associated with use of a variable balance factor employed in the pip 25 calculation are potentially alleviated using hbi iii

on large outflows of arctic sea ice into the barents sea 1 winter outflows of arctic sea ice into the barents sea are estimated using a 10 year record of satellite ice motion and thickness the mean winter volume export through the svalbard franz josef land passage is 40 km3 and ranges from 280 km3 to 340 km3 a large outflow in 2003 is preconditioned by an unusually high concentration of thick perennial ice over the nansen basin at the end of the 2002 summer with a deep atmospheric low situated over the eastern barents sea in winter the result is an increased export of arctic ice the oct mar ice area flux at 110 103 km2 is not only unusual in magnitude but also remarkable in that 70 of the area is multiyear ice the ice volume flux at 340 km3 is almost one fifth of the ice flux through the fram strait another large outflow of arctic sea ice through this passage comparable to that in 2003 is found in 1996 this southward flux of sea ice represents one of two major sources of freshwater in the barents sea the other is the eastward flux of water via the norwegian coastal current the possible consequences of variable freshwater input on the barents sea hydrography and its impact on transformation of atlantic water en route to the arctic ocean are examined with a 25 year coupled ice ocean model

a chronosequence of rapid leaching of mixed podzol soil materials following sand mining abstract pedogenesis was investigated on soils which were rehabilitated following mining of late pleistocene sand dunes at tomago on the east coast of australia the soils were rehabilitated by spreading stockpiled a1 horizon material over mixed a2 and b horizon materials from the original humus podzols a four stage chronosequence of 1 5 11 and 17 years since soil rehabilitation was established and changes in ph organic carbon and pyrophosphate and oxalate extractable fe and al were investigated an a2 horizon extending to at least the depth of the water table developed over the chronosequence by leaching of organic carbon and oxalate extractable fe and al eighty one percent of the leaching occurred between 1 and 5 years after soil rehabilitation at a mass loss rate of 3 0 t ha 1 yr 1 such rapid leaching led to thicker a2 horizons than before mining which is attributed to physical destruction of the indurated b1 horizon and its homogenisation with a2 and 132 material to form a permeable mass containing easily translocated forms of fe and a1 inorganic forms of fe and al were found to be more mobile than organic forms

periglacial geomorphology of the appalachian highlands and interior highlands south of the glacial border a review abstract many features reported in the appalachian region have been assigned a paleoperiglacial origin based on field relationships and their similarities with analogs active in present day actuoperiglacial environments these forms include but are not limited to sorted and nonsorted varieties of patterned ground grezes litees block fields block slopes and block streams cryoplanation terraces and hillslope and river terrace landscapes although very small scale features generally less than 1 m in plan or section dimension and some larger forms on steep hillslopes are known to be at least sporadically active today the large scale features discussed here are interpreted as either inactive or truly fossil periglacial phenomena thus they hav implications for paleoclimatic reconstruction and significance as indicators of relative landscape stability since the time s of their development this paper briefly reviews the historical dimension of early researchs work present selected examples of recent results and gives authors conclusions

dynamics and extent of the weichselian permafrost in western europe substage 5e to stage 1 abstract a paleoclimate sequence and a map of the successive extensions of the permafrost during the different stages of the weichselian is proposed on the basis of cryopedological and paleopedological data this work shows the existence of two periglacial cycles within the weichselian both are characterized by later permafrost in the oceanic provinces of europe compared with northern france and belgium explanations are given for the origin of the pomeranian and dryas stadials

characteristics and palaeoenvironmental significance of relict sorted patterned ground drakensberg plateau southern africa abstract relict large sorted periglacial circles are described from the drakensberg plateau of southern africa morphological and sedimentological data for three populations of patterns occurring on high summit 3400 m a s l interfluves are presented the patterns range between 85 and 904 cm in diameter with centres encircled by primary and in some cases secondary borders patterns are sorted to maximum depths of 85 cm or more with borders occupying trough like depressions to a depth of 26 cm although it is found that contemporary freeze to 40 cm depth still permits some cryogenic activity within smaller patterns it is argued that the larger patterns are degrading owing to limited moisture and freeze duration and intensity the paper provides a literature summary of contemporary environmental parameters from 10 northern hemisphere localities where active relict large periglacial patterns occur findings suggest that patterns over 80 cm in diameter develop where the maat is 1 6 c or less it is demonstrated that the drakensberg palaeo maat reached such low temperatures during the lgm it is thus argued that the patterns developed during the lgm and that smaller varieties became reactivated during holocene cold phases the relict sorted circles provide confirmation for late quaternary permafrost above 3400 m a s l in southern africa the results further suggest pronounced palaeo climatic environmental variation over short spacial scales over southern africa s high plateau

a quantitative comparison of soil development in four climatic regimes abstract a new quantitative soil development index based on field data has been applied to chronosequences formed under different climatic regimes the four soil chronosequences developed primarily on sandy deposits have some numeric age control and are located in xeric inland merced calif xeric coastal ventura calif aridic las cruces n mex and udic susquehanna valley pa soil moisture regimes to quantify field properties points are assigned for developmental increases in soil properties in comparison to the parent material currently ten soil field properties are quantified and normalized for each horizon in a given chronosequence including two new properties for carbonate rich soils in addition to the eight properties previously defined when individual properties or the combined indexes are plotted as a function of numeric age rates of soil development can be compared in different climates the results demonstrate that 1 the soil development index can be applied to very different soil types 2 many field properties develop systematically in different climatic regimes 3 certain properties appear to have similar rates of development in different climates and 4 the profile index that combines different field properties increases significantly with age and appears to develop at similar rates in different climates the soil development index can serve as a preliminary guide to soil age where other age control is lacking and can be used to correlate deposits of different geographical and climatic regions

mapping recent sea ice conditions in the barents sea using the proxy biomarker ip25 implications for palaeo sea ice reconstructions abstract an analysis of the sea ice proxy ip 25 and the open water phytoplankton indicator brassicasterol has been carried out for 93 surface sediments collected from the barents sea and some additional data from previous studies have been included to augment the analysis further consistent with a specific and selective sea ice diatom origin for ip 25 this biomarker was identified in virtually all sediments from seasonally ice covered locations but was absent from the majority of sites beyond the maximum sea ice extent msie for the period 1983 2002 in contrast brassicasterol was detected in virtually all sediments from the region and concentrations were not at all associated with the msie instead more localised regions of brassicasterol concentrations were identified and these likely reflect different influences on production and deposition when the ip 25 and brassicasterol concentrations were combined together in the form of the previously proposed p b ip 25 index the aforementioned association between ip 25 occurrence and the msie was clarified further and in addition provided more detailed descriptions of sea ice cover in particular p b ip 25 data indicated seasonal sea ice or marginal ice zone conditions for the region of the barents sea within the msie according to previously defined p b ip 25 ranges we also amalgamated the biomarker data from the current study with those derived previously by muller et al 2011 and compared these larger datasets with satellite derived mean spring sea ice concentrations significantly although the correlation between the combined ip 25 concentration dataset with the satellite data was very similar to that reported previously by muller et al 2011 the corresponding correlation using the p b ip 25 values was poorer with the larger dataset and some possible reasons for this are discussed finally in a small number of cases ip 25 was identified in sediments somewhat distal from the msie and it is hypothesised that the occurrence of ip 25 in these sediments results from allochthonous input following sediment advection between shelf and trough environments this is the first reported example that provides evidence for the allochthonous input of ip 25 into marine sediments and it is recommended that this should be considered carefully when carrying out palaeo sea ice reconstructions based on the occurrence of this biomarker in the future

atlantic water advection versus sea ice advances in the eastern fram strait during the last 9 ka multiproxy evidence for a two phase holocene a sediment core from the west spitsbergen continental margin was studied to reconstruct climate and paleoceanographic variability during the last 9 ka in the eastern fram strait our multiproxy evidence suggests that the establishment of the modern oceanographic configuration in the eastern fram strait occurred stepwise in response to the postglacial sea level rise and the related onset of modern sea ice production on the shallow siberian shelves the late early and mid holocene interval 9 to 5 ka was generally characterized by relatively unstable conditions high abundance of the subpolar planktic foraminifer species turborotalita quinqueloba implies strong intensity of atlantic water aw inflow with high productivity and or high aw temperatures resulting in a strong heat flux to the arctic a series of short lived cooling events 8 2 6 9 and 6 1 ka occurred superimposed on the warm late early and mid holocene conditions our proxy data imply that simultaneous to the complete postglacial flooding of arctic shallow shelves and the initiation of modern sea ice production strong advance of polar waters initiated modern oceanographic conditions in the eastern fram strait at 5 2 ka the late holocene was marked by the dominance of the polar planktic foraminifer species neogloboquadrina pachyderma a significant expansion of sea ice icebergs and strong stratification of the water column although planktic foraminiferal assemblages as well as sea surface and subsurface temperatures suggest a return of slightly strengthened advection of subsurface atlantic water after 3 ka a relatively stable cold water layer prevailed at the sea surface and the study site was probably located within the seasonally fluctuating marginal ice zone during the neoglacial period

differential frost heave model for patterned ground formation corroboration with observations along a north american arctic transect 1 frost boils in the arctic are a manifestation of patterned ground in the form of nonsorted circles active frost boils involve convection of water through the soil that can bring basic salts from depth to the surface as such active frost boils can mitigate acidification and thereby strongly influence the type of vegetation supported by arctic soils the presence or absence of active frost boils is thought to play a pivotal role in establishing the sharp demarcation between moist nonacidic tundra mnt and moist acidic tundra mat in the arctic the focus of this paper is to corroborate the predictions of a mathematical model that relates observable patterned ground features to ecosystem parameters with observations at the field sites along the north american arctic transect naat established by the biocomplexity of patterned ground ecosystems project model predictions indicate that recurrent one dimensional frost heave can become unstable and evolve into multidimensional differential frost heave dfh a laboratory frost heave simulation produced a 28 cm pattern in an active layer of 10 cm which agrees with linear stability theory predictions a finite element solution predicts three dimensional patterns with approximately 3 m spacing develop in a 1 0 m active layer with a surface n factor of 0 35 which agrees well with field observations from the naat the lack of significant frost boil activity in the mat is a result of suppression of dfh owing to denser surface vegetation characterized by low n factors prominent active frost boils are observed in the mnt at higher latitudes with more sparse vegetation characterized by higher n factors that promote dfh however at the northernmost field sites frost boils cannot be generated even though the n factors are relatively high owing to very rapid freezing conditions that mitigate dfh

circulation and transformation of atlantic water in the eurasian basin and the contribution of the fram strait inflow branch to the arctic ocean heat budget abstract the inflows of atlantic water from the nordic seas to the arctic ocean through fram strait and over the barents sea are examined and their pathways and transformations in the eurasian basin are described based primarily on hydrographic observations from two cruises with rv polarstern in 2007 and 2011 the contrast between the high salinity atlantic water core in the nansen basin and the lower atlantic water salinity in the amundsen basin combined with a salinity minimum below the atlantic layer suggest that the fram strait branch mainly remains in the nansen basin while the barents sea branch continues along the continental slope enters the amundsen basin and provides most of the atlantic water in the makarov and canada basins to examine the consequences of such a circulation pattern recently published estimates of the in and outflows of volume and liquid freshwater through the barents sea bering strait and the canadian arctic archipelago as well as river runoff net precipitation and ice export are reviewed and added together to achieve volume and freshwater balances net outflows through fram strait of 2 3 sv and 100 msv respectively are required this is reasonably close to the recently reported fram strait transport estimates the net outflows are separated into two parts upper layer transports less dense than the entering atlantic water and lower layer transports as dense as or denser than the atlantic water the largest net volume outflow occurs in the lower layer 1 65 sv while the liquid freshwater is almost exclusively exported in the 0 64 sv net outflow in upper layer leading to unrealistically low salinities in the upper layer compared with observations atlantic water is north of svalbard transformed into less saline surface water through melting of sea ice which can supply the necessary higher salinity halocline water to the upper layer 1 23 sv of halocline water of salinity 34 2 must be added to obtain a more realistic salinity of 33 1 leading to a total export of 1 84 sv upper layer water in the east greenland current existing observations of the net transports into and out of the arctic ocean through fram strait in different temperature classes are used to estimate the heat loss of the atlantic water entering the arctic ocean through fram strait about 10 tw are supplied to the atmosphere in addition to the loss of 24 tw occurring in connection with the formation of the halocline water if the hypothesis that the fram strait branch remains in the nansen basin is true it implies a heat loss between 5 and 15 w m 2 in the nansen basin depending upon how much heat is temporarily stored in the water column this is high compared to the 2 w m 2 commonly cited as the ocean heat flux to the atmosphere in the arctic ocean

neogloboquadrina pachyderma sinistral coiling as paleoceanographic tracers in polar oceans evidence from northeast water polynya plankton tows sediment traps and surface sediments the abundance and chemistry of the planktonic foraminifera neogloboquadrina pachyderma sinistral coiling have long been used as tools for monitoring polar surface ocean changes and for correlating these changes to atmospheric and thermohaline circulation fluctuations however due to its remote habitat very little is known about how modern n pachyderma s respond to changing environmental conditions in the polar seas modern samples of n pachyderma s from the northeast water polynya provide a means for studying how environmental conditions affect the vertical distribution and chemistry of this species highest abundances of n pachyderma s were associated with the chlorophyll maximum in the surface 20 80 m where they are exploiting their primary food source evidence suggests that the addition of a calcite crust modifies the calcite tests of some n pachyderma s between 50 and 200 m increasing shell density and modifying shell chemistry the shell mass of encrusted forms is 3 4 times greater than the nonencrusted forms between 50 and 200 m the oxygen isotope composition of n pachyderma s shells increase by 1 5 in response to local water column gradients the 13c values of n pachyderma s are basically invariant with depth in this region are consistently 1 0 depleted in comparison with the 13c for equilibrium calcite and remain basically constant during the shell thickening process mass balance calculations suggest that encrustation occurs at all depths but abundance counts suggest that the process occurs mostly at the depth of the main pycnocline sediment fluxes of n pachyderma s occur during a 2 week bloom event and decrease to almost zero below complete ice cover the decoupling of the processes controlling abundances and shell chemistry explain the discrepancies between transfer function and isotopically derived paleotemperature estimates of surface conditions in some oceanic settings the ability of 18o to record surface ocean conditions will depend on vertical water column gradients as evidenced by the differences in core top calibrations between the north and south atlantic

small scale variability of soil properties and soil vegetation relationships in patterned ground on different lithologies nw italian alps abstract cryogenic patterned ground represents spectacular periglacial landscapes on the alps sorted nonsorted patterned ground features larger than 1 m formed by deep seasonal cryoturbation with or without permafrost occupy exposed stable surfaces at high altitudes and represent a particularly harsh habitat for plant life we analyzed soils across transects through typical active patterned ground features sorted nonsorted circles and stripes on four common lithotypes calcschists serpentinite gabbros and gneiss in the western italian alps in order to observe the small scale lateral and depth variability in physico chemical properties and their association with cryoturbation plant cover and species distribution cryoturbation was correlated with lateral vertical textural sorting across features mostly visible on silt and coarse sand but with opposite trends on sorted and nonsorted patterned ground types a strong lateral variability in organic carbon was detected with high values near the better vegetated rims and low contents in the centers exchangeable bases heavy metals and nutrients followed the same distribution however the differences inherited from the parent materials were overwhelming climate is the main driver of high altitude ecosystems reducing total plant cover and causing cryoturbation which in turn creates strong edaphic gradients over small distances plant species and communities are well correlated with edaphic properties inherited from the parent materials such as exchangeable ca and heavy metals

the principles of cryostratigraphy abstract cryostratigraphy adopts concepts from both russian geocryology and modern sedimentology structures formed by the amount and distribution of ice within sediment and rock are termed cryostructures typically layered cryostructures are indicative of syngenetic permafrost while reticulate and irregular cryostructures are indicative of epigenetic permafrost cryofacies can be defined according to patterns of sediment characterized by distinct ice lenses and layers volumetric ice content and ice crystal size cryofacies can be subdivided according to cryostructure where a number of cryofacies form a distinctive cryostratigraphic unit these are termed a cryofacies assemblage the recognition if present of i thaw unconformities ii other ice bodies such as vein ice ice wedges aggradational ice and thermokarst cave pool ice and iii ice sand and gravelly pseudomorphs is also important in determining the nature of the freezing process the conditions under which frozen sediment accumulates and the history of permafrost

paleoceanographic evolution of the sw svalbard margin 76 n since 20 000 14c yr bp abstract two cores from the southwestern shelf and slope of storfjorden svalbard taken at 389 m and 1485 m water depth have been analyzed for benthic and planktic foraminifera oxygen isotopes and ice rafted debris the results show that over the last 20 000 yr atlantic water has been continuously present on the southwestern svalbard shelf however from 15 000 to 10 000 14c yr bp comprising the heinrich event h1 interval the bolling allerod interstades and the younger dryas stade it flowed as a subsurface water mass below a layer of polar surface water in the benthic environment the shift to interglacial conditions occurred at 10 000 14c yr bp due to the presence of a thin upper layer of polar water surface conditions remained cold until ca 9000 14c yr bp when the warm atlantic water finally appeared at the surface neither extensive sea ice cover nor large inputs of meltwater stopped the inflow of atlantic water its warm core was merely submerged below the cold polar surface water

stone runs in the falkland islands periglacial or tropical abstract stone runs is the falklands vernacular term for openwork boulder accumulations which include extensive blockstreams like the famous darwin stone river and associated features such as stone stripes since the early 20th century they have been interpreted as the product of a suite of periglacial processes including frost wedging gelifluction frost heave frost sorting and snowmelt runoff following a literature review the results of recent field investigations of the valley floor blockstreams of east falkland are presented access to the internal structure of these forms provides evidence for the existence of a three fold profile with clear vertical size gradation presenting striking similarities with an inverted weathering profile micromorphological analyses sem xrd thin sections and grain size analyses lead to the hypothesis of an alternative model of stone run formation it is suggested that the material forming the stone run profile lato sensu including the superficial pavement is not of periglacial origin but derives directly from the stripping and accumulation downslope of a regolith possibly tertiary in age and formed under subtropical or temperate conditions the valley floor stone runs should therefore be considered as complex polygenetic landforms that may have formed according to a six stage scenario including in situ chemical weathering regolith stripping by mass movements soil formation further regolith stripping downslope accumulation and matrix washing out all phases possibly achieved by the early quaternary periglacial reworking of the stone run material would have operated at a final stage i e during quaternary cold stages with boulder bioweathering and limonite staining operating during the temperate intervals including the present one the suggested antiquity of the falklands blockstreams is in accordance with caine s pioneer interpretation of tasmania blockfields and with recent analyses and cosmogenic datings of blockfields from scandinavia and north america

relict periglacial slope deposits in the hex river mountains south africa observations and palaeoenvironmental implications abstract shattered bedrock near the summit of matroosberg western cape mountains is closely associated with several blockstreams which grade downslope into broad terraces with an increase in slope angles the regolith grades into broad bands of coarse but sorted material parallel to the maximum gradient the width of the coarse stripes increases in the downslope direction where they merge into openwork block deposits several tens of metres long and wide whereas the terraces near the summit plateau closely resemble gelifluction sheets the large sorted stripes and coarse debris mantles are analogous to the stone banked terraces described for the colorado front range the landforms are primarily related to seasonal frost creep at the last glacial maximum lgm when mean annual temperatures are estimated to have been around 0 c i e winter temperatures 7 8 c lower than present snowcover must have been limited to allow deep frost penetration

climate and material controls on periglacial soil processes toward improving periglacial climate indicators one of the distinguished efforts of a l washburn was to reconstruct mean annual air temperature using periglacial features as climate indicators this paper reviews existing periglacial indicators and proposes a strategy to improve their thermal resolution based on recent periglacial process studies with a focus on solifluction and thermal contraction cracking and associated landforms structures landforms resulting from solifluction reflect both the depth subjected to freeze thaw and the thickness of frost susceptible soils the thickness of a solifluction structure can be used to infer the dominant freeze thaw regime and minimum seasonal frost depth ice wedge pseudomorphs have limited potential as a climate indicator because 1 they mainly reflect extreme winter temperatures 2 their thermal thresholds depend on the host material and 3 they need to be distinguished from frost wedges of other origin produced under different thermal and or material conditions monitoring studies of currently active ice wedges suggest that ice wedge cracking requires a combination of low temperature and large temperature gradients in the frozen active layer further field monitoring of periglacial processes and their controlling factors under various climate conditions and in various materials are needed however to improve the resolution of periglacial paleoclimate indicators

striking similarities in temporal changes to spring sea ice occurrence across the central canadian arctic archipelago over the last 7000 years abstract a 7000 year spring sea ice record for victoria strait arc 4 and dease strait arc 5 in the canadian arctic archipelago caa has been determined by quantification of the sea ice diatom derived biomarker ip 25 in two marine sediment piston cores obtained in 2005 the chronologies of the arc 4 and arc 5 cores were determined using a combination of 14 c ams dates obtained from macrobenthic fossils and magnetic susceptibility measurements the ages of the tops of the piston cores were estimated by matching chemical and physical parameters with those obtained from corresponding box cores these analyses revealed that while the top of the arc 4 piston core was estimated to be essentially modern ca 60 cal yr bp a few hundred years of sediment appeared to be absent from the arc 5 piston core downcore changes to ip 25 fluxes for both cores were interpreted in terms of variations in spring sea ice occurrence and correlations between the individual ip 25 flux profiles for victoria strait dease strait and barrow strait reported previously were shown to be statistically significant at both 50 and 100 year resolutions the ip 25 data indicate lower spring sea ice occurrences during the early part of the record ca 7 0 3 0 cal kyr bp and for parts of the late holocene ca 1 5 0 8 cal kyr bp especially for the two lower latitude study locations in contrast higher spring sea ice occurrences existed during ca 3 0 1 5 cal kyr bp and after ca 800 cal yr bp the observation of consecutively lower and higher spring sea ice occurrence during two periods of the late holocene coincides broadly with the medieval warm period and little ice age epochs respectively the ip 25 data are complemented by particle size and mineralogical data although these may alternatively reflect changes in sea level at the study sites the ip 25 data are also compared to previous proxy based determinations of palaeo sea ice and palaeoclimate for the caa including those based on bowhead whale remains and dinocyst assemblages the spatial consistency in the proxy data which most notably indicates an increase in spring sea ice occurrence around 3 cal kyr bp provides a potentially useful benchmark for the termination of the holocene thermal maximum for the central caa

stable isotopes in planktonic and benthic foraminifera from arctic ocean surface sediments oxygen and carbon isotopic analyses have been performed on the tests of planulina wuellerstorfi and three size fractions of sinistral neogloboquadrina pachyderma recovered from 33 arctic ocean surface sediment samples stable isotopic compositions of n pachyderma are found to be dependent on the test size larger specimens show considerable enrichment in both 18o and 18c the difference between the isotopic compositions of the 63 125 and 125 250 m size fractions in n pachyderma can be explained by biogenic fractionation effects during foraminiferal test growth larger 250 500 m n pachyderma displayed accretions of secondary calcite i e the outermost shell contained significant amounts of inorganically precipitated magnesium calcite thus larger foraminifera may not be suited for down core stable isotopic studies there is a difference of 2 between 18o values of surface samples from the eastern and western arctic ocean reflecting large differences between surface water salinity in these re

early holocene temperature variability in the nordic seas the role of oceanic heat advection versus changes in orbital forcing received 7 january 2011 revised 15 july 2011 accepted 21 july 2011 published 22 october 2011 1 the separate roles of oceanic heat advection and orbital forcing on influencing early holocene temperature variability in the eastern nordic seas is investigated the effect of changing orbital forcing on the ocean temperatures is tested using the 1dice model and the 1dice results are compared with new and previously published temperature reconstructions from a transect of five cores located underneath the pathway of atlantic water from the faroe shetland channel in the south to the barents sea in the north the stronger early holocene summer insolation at high northern latitudes increased the summer mixed layer temperatures however ocean temperatures underneath the summer mixed layer did not increase significantly the absolute maximum in summer mixed layer temperatures occurred between 9 and 6 ka bp representing the holocene thermal maximum in the eastern nordic seas in contrast maximum in northward oceanic heat transport through the norwegian atlantic current occurred approximately 10 ka bp the maximum in oceanic heat transport at 10 ka bp occurred due to a major reorganization of the atlantic ocean circulation entailing strong and deep rejuvenation of the atlantic meridional overturning circulation combined with changes in the north atlantic gyre dynamic causing enhanced transport of heat and salt into the nordic seas

paleoceanographic reconstructions of surface ocean conditions in the greenland iceland and norwegian seas through the last 14 ka based on diatoms prior reconstructions of the last glacial maximum and the holocene did not include detailed paleoclimate data from the greenland iceland and norwegian gin seas which cover sensitive areas for oceanographic boundaries sea ice distribution and deep water formation in order to fill this gap we studied nine well dated sediment cores from this area and reconstructed the paleoceanographic conditions of the surface gin seas at 2000 year intervals since 13 400 bp based on the diatom record results show that a n s extending sea ice free corridor had opened along norway already at 13 400 bp indicating a northward flow of a branch of the north atlantic drift possibly caused by a change in the jet stream flow due to the decreased height of the north american ice sheet a major change of climatic conditions occurred over the gin seas as the insolation anomaly reached its maximum around 9000 bp when the sea ice cover and the oceanic fronts retreated to a northwesterly position along greenland and the ocean temperatures rose the first half of the holocene is recorded as the warmest period during the last 13 400 bp in the gin seas the duration of this climatic optimum decreased both toward the north and toward the margins of the area the second half of the holocene is characterized by a cooling trend in step with the decreasing insolation these results support the proposal of imbrie et al 1992 that the gin seas region acts as an initial responder to insolation changes

frost and soils implications for paleosols paleoclimates and stratigraphy abstract frost is a pedogenetic agent this paper describes the use of frost features in soil for paleoclimatic and stratigraphic interpretation it is possible to differentiate periods of frost activity from those of temperate pedogenesis by macroscopic and microscopic criteria and to distinguish between soils with pre syn and epigenetic frost effects an experimental approach is necessary to determine initial frost effects because they are usually difficult to observe at natural active sites work with ecologists also clarifies the evolution of frost affected soils under climatic and vegetational constraints vegetation has important effects on the thermal and hydraulic regimes of soils and on erosion susceptibility the recognition of fossil cryosoils often allows the reconstruction of sequences of paleoclimatic events in periods or environments with little or no micropaleontological evidence the interrelations between frost and other pedogenetic processes allow a better understanding of climatic evolution and deterioration throughout the neogene and especially during the quaternary and the holocene most of the inherited frost features in european soils are younger than 480 ka bp the differentiation between frost and tectonic perturbations is very important for calculation of soil erosional budgets