the seasonal water temperature cycle in the arctic dicksonfjord svalbard during the holocene climate optimum derived from subfossil arctica islandica shells future climate change will have significant effects on ecosystems worldwide and on polar regions in particular hence palaeo environmental studies focussing on the last warmer than today phase i

a balanced section across the pyrenean orogenic belt evolutionary models that have been proposed for the pyrenean orogenic belt involve gravitational gliding of major thrust sheets to both the north and south of an uplifted central axial zone it has been suggested by previous workers that uplift is a result of alpine compression or long lived strike slip movement on the north pyrenean fault we critically assess these models and propose a new model based on the generation of a thin skinned linked thrust system due to alpine collision of iberia and europe pyrenean alpine tectonics is dominated by southward thrusting on a major sole fault dipping north at approximately 6 within hercynian basement northerly directed thrusts of the north pyrenean zone and northern folded foreland are backthrusts from this sole fault a total orogenic shortening of 106 km in the central pyrenees was achieved between the palaeocene and oligocene at a time averaged rate of 0 62 cm yr 1 a thin skinned model requires that the north pyrenean fault is truncated by both northward and southward moving thrusts and occurs in the footwall of the sole fault some 60km north of its present surface trace

holocene glacial and climatic variations on spitsbergen svalbard holocene glacial and climatic variations have been inferred from investigations of sediment cores from the proglacial lake linnevatnet western spitsbergen a low content of glacially derived coal absence of regular laminations and a slow sedimentation rate in the lower part of the lacustrine sediments indicate that the former glaciers that existed within the catchment area during the last ice age melted quickly away as a result of the younger dryas holocene warming and during the next 6000 years there were no glaciers in the valley increasing coal content incipient laminations and rising sedimentation rates indicate that the glacier linnebreen started to form 4000 5000 years ago probably as a response to the late holocene cooling the holocene maximum extent of the glacier occurred during the little ice age starting with a pronounced ice advance in the thirteenth or fourteenth century a well dated core from billefjorden which is assumed to reflect glacial fluctuations in the inner part of the i

a late glacial early holocene multiproxy record from the eastern fram strait polar north atlantic the paleoceanographic development of the eastern fram strait during the transition from the cold late glacial and into the warm early holocene was elucidated via a multiproxy study of a marine sediment record retrieved at the western svalbard slope the multiproxy study includes analyses of planktic foraminiferal fauna bulk sediment grain size and caco3 content in addition to mg ca ratios and stable isotopes delta c 13 and delta o 18 measured on the planktic foraminifer neogloboquadrina pachyderma furthermore paleosubsurface water temperatures were reconstructed via mg ca ratios ssst mg ca and transfer functions ssst transfer enabling comparison between the two proxies within a single record the age model was constrained by four accelerator mass spectrometry ams c 14 dates from 14 000 to 10 300 cal yr b p n pachyderma dominated the planktic fauna and cold polar sea surface conditions existed the period was characterized by extensive sea ice cover iceberg transport and low subsea surface temperatures ssst transfer similar to 2 1 degrees c ssst mg ca similar to 3 5 degrees c resulting in restricted primary production atlantic water inflow was reduced compared to the present day and likely existed as a subsurface current at ca 10 300 cal yr b p atlantic water inflow increased and the arctic front retreated north westward resulting in increased primary productivity higher foraminiferal fluxes and a reduction in sea ice cover and iceberg transport the fauna rapidly became dominated by the subpolar planktic foraminifer turborotalita quinqueloba and summer ssst transfer increased by similar to 3 5 degrees c concurrently the ssst mg ca recorded by n pachyderma rose only similar to 0 5 degrees c from ca 10 300 to 8600 cal yr b f the average ssst mg ca and ssst transfer were similar to 4 0 degrees c and similar to 55 degrees c respectively the relatively modest change in ssst mg ca compared to ssst transfer can probably be tied to a change of the main habitat depth and or shift in the calcification season for n pachyderma during this period

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

lateglacial and early holocene climatic oscillations on the western svalbard margin european arctic abstract a multi proxy sediment core record on the continental margin off western svalbard european arctic reflects large climatic and oceanographic oscillations at the lateglacial early holocene transition based on studies of planktonic foraminifera their stable oxygen and carbon isotopic composition and ice rafted debris we have reconstructed the last 14 cal ka bp the period 14 13 5 cal ka bp was characterized by highly unstable climatic conditions short lived episodes of warming alternated with meltwater pulses and enhanced iceberg rafting this period correlates to a regional warming of the northern north atlantic an overall decrease in meltwater took place during the deglaciation 14 10 8 cal ka bp the late younger dryas and subsequent transition into the early holocene is characterized by a reduced flux of planktonic foraminifera and increased iceberg rafting a major warming took place from 10 8 to 9 7 cal ka bp the influence of meltwater ceased and the flux of warm atlantic water increased from 9 7 to 8 8 cal ka bp the western svalbard margin surface waters were significantly warmer than today this warm period the thermal maximum was followed by an abrupt cooling at 8 8 cal ka bp caused by an increased influence of arctic water from the arctic ocean the results document that the european arctic was very sensitive to climatic and oceanographic changes at the end of the last glacial and during the holocene

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

the holocene thermal maximum around svalbard arctic north atlantic molluscs show early and exceptional warmth shallow marine molluscs that are today extinct close to svalbard because of the cold climate are found in deposits there dating to the early holocene the most warmth demanding species found zirfaea crispata currently has a northern limit 1000 km farther south indicating that august temperatures on svalbard were 6 c warmer at around 10 2 9 2 cal ka bp when this species lived there the blue mussel mytilus edulis returned to svalbard in 2004 following recent warming and after almost 4000 years of absence excluding a short re appearance during the medieval warm period 900 years ago mytilus first arrived in svalbard at 11 cal ka bp indicating that the climate was then as least as warm as present this first warm period lasted from 11 to 9 cal ka bp and was followed by a period of lower temperatures 9 8 2 cal ka bp after 8 2 cal ka the climate around svalbard warmed again and although it did not reach the same peak in temperatures as prior to 9 ka it was nevertheless some 4 c warmer than

holocene paleoceanography and glacial history of the west spitsbergen area euro arctic margin two sediment cores from the west spitsbergen area euro arctic margin md99 2304 and md99 2305 have been investigated for paleoceanographic proxies including benthic and planktonic foraminifera benthic foraminiferal stable isotopes and ice rafted debris core md99 2304 is located on the upper continental margin reflecting variations in the influx of atlantic water in the west spitsbergen current core md99 2305 is located in van mijenfjord picturing variations in tidewater glacier activity as well as fjordocean circulation changes surface water warmer than today was present on the margin as soon as the van mijenfjord was deglaciated by 11 200 cal years bp relatively warm water invaded the fjord bottom almost immediately after the deglaciation a relatively warm early holocene was followedby an abrupt cooling at 8800 cal years bp on the continental margin another cooling in the fjord record 8000 4000 cal years bp is documented by an increase in ice rafted debris and an increase in benthic foraminiferal d 18 o the ird record indicates that central spitsbergen never was completely deglaciated during the holocene relatively cool andstable cond itions similar to the present were establishedabout 4000 cal years bp

marine molluscs and late quaternary environmental studies with particular reference to the late glacial period in northwest europe a review abstract although it is now commonly thought that temperature is a minor factor in limiting the distribution of marine invertebrates particularly on a local scale there is evidence to suggest that some boreal molluscs particularly those which occur in similar environments on both sides of the north atlantic are valuable as oceanic temperature indicators this applies particularly to planktotrophic species whose northern limits of distribution are apparently controlled by summer surface temperature the oceanography of the eastern north atlantic is briefly considered in relation to zoogeographic subdivisions based on temperature and it is concluded that the latter are fairly crude and apply only to shelf seas most glaciomarine molluscan faunas are not specific to that environment an exception being that dominated by the bivalve portlandia arctica the role of marine molluscs in palaeoenvironmental research at the local level for the 13 11 ka bp period is illustrated by a site at inchinnan scotland it is concluded that a shell bed at this locality consists partly of a little modified life assemblage and partly of shells which have been gently reworked under conditions of generally rapid deposition during the same time interval the changing composition of molluscan faunas on the nw european seaboard suggests that a weak drift of north atlantic water replaced polar water at or a little later than 13 ka bp off scotland and a few hundred years later off northern norway evidence for relatively warm intervals early and late in the 13 11 ka bp period has been found particulary on the scottish coast and to a lesser extent more generally the later warm interval may be related to the southward movement of the polar front at the beginning of the younger dryas the value of the bivalve shell itself in the determination of temperature seasonality and calendar years is briefly discussed

ore textures and remobilization mechanisms of the hongtoushan copper zinc deposit liaoning china abstract the hongtoushan copper zinc deposit is a volcanic associated massive sulfide deposit in the archean greenstone belt in liaoning china polymetamorphism has resulted in changes to the composition and textures of minerals in the deposit along with remobilization during metamorphism the original alteration minerals that formed with the ore minerals such as chlorite and sericite were transformed into cordierite anthophyllite and phlogopite after further remobilization new minerals such as gahnite and actinolite were formed in this process the original textures were destroyed and new textures were formed including recrystallization and growth textures brittle and ductile deformation textures durchbewegung textures replacement textures chalcopyrite disease and retrograde textures the ore forming components underwent two periods of remobilization in the first early stage mechanical remobilization was important and formed a high grade cu zn au ag ore pillar along the vertical hinge of a synformal fold in the second late stage the mixed hydrothermal mechanical remobilization affected the ores and was typically characterized by matrix sulfides together with silicate minerals moving from the matrix into individual fractured pyrite metablasts and replacing them to varying degrees

the spatial and temporal complexity of the holocene thermal maximum the holocene thermal maximum a period of relatively warm climate between 11 000 and 5 000 years ago1 2 is most clearly recorded in the middle and high latitudes2 3 of the northern hemisphere where it is generally associated with the local orbitally forced summer insolation maximum however proxy based reconstructions have shown that both the timing and magnitude of the warming vary substantially between different regions2 3 4 suggesting the involvement of extra feedbacks and forcings here we simulate the holocene thermal maximum in a coupled global ocean atmosphere vegetation model we find that before 7 000 years ago summers were substantially cooler over regions directly influenced by the presence of the laurentide ice sheet whereas other regions of the northern hemisphere were dominated by orbital forcing our simulations suggest that the cool conditions arose from a combination of the inhibition of labrador sea deep convection by the flux of meltwater from the ice sheet which weakened northward heat transport by the ocean and the high surface albedo of the ice sheet we thus conclude that interglacial climate is highly sensitive to relatively small changes in ice sheet configuration

holocene evolution of the western greenland ice sheet assessing geophysical ice sheet models with geological reconstructions of ice margin change abstract geophysical ice sheet models are used to predict future ice sheet dimensions and in turn these projections help estimate the magnitude of eustatic sea level rise before models can confidently predict ice sheet behavior they must be validated by being able to duplicate the geological record of ice sheet change here we review geological records of greenland ice sheet gris change with emphasis on the warmer than present middle holocene and compare these records to published studies that numerically simulate gris behavior through the holocene geological records are concentrated in west and southwest greenland which are also the regions where the gris margin likely experienced the greatest distance of inland retreat during the middle holocene several records spanning from melville bugt to jakobshavn isfjord in western greenland indicate the gris achieved its minimum extent between 5 and 3 ka and farther south in the kangerlussuaq region new data presented here indicate the ice margin reached its minimum extent between 4 2 and 1 8 ka in the narsarsuaq region in southern greenland the gris likely achieved its minimum configuration between 7 and 4 ka we highlight key similarities and discrepancies between these reconstructions and model results and finally we suggest that despite some degree of inland retreat the west and southwest gris margin remained relatively stable and close to its current position through the holocene thermal maximum

chronology of the last recession of the greenland ice sheet a new deglaciation chronology for the ice free parts of greenland the continental shelf and eastern ellesmere island canada is proposed the chronology is based on a new compilation of all published radiocarbon dates from greenland and includes crucial new material from southern northeastern and northwestern greenland although each date provides only a minimum age for the local deglaciation some of the dates come from species that indicate ice proximal glaciomarine conditions and thus may be connected with the actual ice recession in addition to shell dates dates from marine algae lake sediments peat terrestrial plants and driftwood also are included only offshore and in the far south have secure late glacial sediments been found other previous reports of late glacial sediments older than 11 5 cal kyr bp from onshore parts of greenland need to be confirmed most of the present ice free parts of greenland and nares strait between greenland and ellesmere island were not deglaciated until the early holocene copyright c 2002 john wiley sons ltd less

post glacial relative sea level history of northwestern spitsbergen svalbard the late weichselian and holocene raised beach sequences on northwestern spitsbergen provide a detailed record of sea level oscillations during the last deglacial hemicycle initial emergence commenced at 13 ka coincident with local deglaciation and until 10 5 ka was characterized by a relative slow rate of emergence 1 5 to 5 m ka interrupted by minor stillstands or transgressions associated with possible glacier re advances the orientation of paleo spits and the paucity of whale remains at the late weichselian marinelimit indicate that the prevailing westerly fetch was dampened by a semi permanent sea ice cover allowing long shore drift to predominate a period of accelerated emergence 15 to 30 m ka between 10 5 and 9 ka is correlative with rapid deglaciation of fiords the middle and late holocene is characterized by two brief transgressions one between 6 5 and 5 0 ka that did not exceed 7 m asl and a present probable slow rise in sea level that commenced 2 to 1 ka the strandline tilts in northwestern spitsbergen and the pattern and rate of emergence on svalbard indicate that the maximum glacier loads during the late weichselian were centered on nordaustlandet and on the central and eastern part of the archipelago northwestern and southwestern spitsbergen were marginal to glacial loading and were deglaciated early 13 ka which is presently incompatible with maximum ice sheet extent and the timing and position of deglacial margins recently reconstructed for the barents sea and svalbard mountain ranges and large fiords probably confined major outlet glaciers to the central part of the archipelago preventing inundation of much of western spitsbergen by an inferred large ice sheet based in eastern svalbard and the barents sea

holocene sea subsurface and surface water masses in the fram strait comparisons of temperature and sea ice reconstructions highlights holocene sea subsurface temperatures after husum hald 2012 estimated from planktic foraminifer fauna in e fram strait biomarkers and ip25 derived indices including dip25 indicate surface water variability delayed onset of early holocene conditions in subsurface 10 6 ka compared to surface 11 7 ka water conditions warm atlantic layer likely occupied uppermost 200 m in eastern fram strait between 10 and 9 ka diverging late holocene trends in surface and subsurface conditions linked to presence of strong pycnocline stratification abstract two high resolution sediment cores from eastern fram strait have been investigated for sea subsurface and surface temperature variability during the holocene the past ca 12 000 years the transfer function developed by husum and hald 2012 has been applied to sediment cores in order to reconstruct fluctuations of sea subsurface temperatures throughout the period additional biomarker and foraminiferal proxy data are used to elucidate variability between surface and subsurface water mass conditions and to conclude on the holocene climate and oceanographic variability on the west spitsbergen continental margin results consistently reveal warm sea surface to subsurface temperatures of up to 6 c until ca 5 cal ka bp with maximum seawater temperatures around 10 cal ka bp likely related to maximum july insolation occurring at that time maximum atlantic water aw advection occurred at surface and subsurface between 10 6 and 8 5 cal ka bp based on both foraminiferal and dinocyst temperature reconstructions probably a less stratified ice free nutrient rich surface ocean with strong aw advection prevailed in the eastern fram strait between 10 and 9 cal ka bp weakened aw contribution is found after ca 5 cal ka bp when subsurface temperatures strongly decrease with minimum values between ca 4 and 3 cal ka bp cold late holocene conditions are furthermore supported by high planktic foraminifer shell fragmentation and high 18o values of the subpolar planktic foraminifer species turborotalita quinqueloba while ip25 associated indices as well as dinocyst data suggest a sustained cooling due to a decrease in early summer insolation and consequently sea ice increase since about 7 cal ka bp in surface waters planktic foraminiferal data including stable isotopes indicate a slight return of stronger subsurface aw influx since ca 3 cal ka bp the observed decoupling of surface and subsurface waters during the later holocene is most likely attributed to a strong pycnocline layer separating cold sea ice fed surface waters from enhanced subsurface aw advection this may be related to changes in north atlantic subpolar versus subtropical gyre activity

the tectonic evolution of the pyrenees a workshop report of a meeting of the tectonic studies group held at the university of cambridge on 21 may 1983 about 70 geologists and geophysicists from britain france holland and spain met to discuss the tectonic evolution of the pyrenees and surrounding areas twenty short talks and 12 posters were presented and the meeting closed with a two hour 9round table9 discussion hercynian geology and alpine overprinting vielzeuf referred to lower crustal granulites of probable hercynian age along the north pyrenean fault zircon age determinations for these rocks are in progress in the aston massif vissers described the progressive folding and transposition of a steep early schistosity suprastructure into a relatively flat lying attitude infrastructure with increasing metamorphic grade the refolding accompanied low pressure metamorphism and probably resulted from tectonic doming during granite emplacement similar low pressure metamorphic rocks and granite petrogenesis in the trois seigneurs massif were discussed in a poster by wickham although comparatively few participants spoke on hercynian orogenesis it appears to have been characterized by unusually high heat flow and intense plutonic activity the tectonic setting of the area at this time remains obscure andrews austin and colwill described high strains measured on pyrite cube pressure shadows in the llavorsi syncline these indicate up to 10 km of hercynian s directed thrust movement in this area a similar reverse displacement with a dextral component on mylonites along the merens fault was described by mccaig and miller 39 ar 40 ar dating clearly shows this movement to be of alpine age and probably

a 10 000 year record of arctic ocean sea ice variability view from the beach we present a sea ice record from northern greenland covering the past 10 000 years multiyear sea ice reached a minimum between 8500 and 6000 years ago when the limit of year round sea ice at the coast of greenland was located 1000 kilometers to the north of its present position the subsequent increase in multiyear sea ice culminated during the past 2500 years and is linked to an increase in ice export from the western arctic and higher variability of ice drift routes when the ice was at its minimum in northern greenland it greatly increased at ellesmere island to the west the lack of uniformity in past sea ice changes which is probably related to large scale atmospheric anomalies such as the arctic oscillation is not well reproduced in models this needs to be further explored as it is likely to have an impact on predictions of future sea ice distribution

collapse of marine based outlet glaciers from the scandinavian ice sheet abstract we present a reconstruction of the timing and retreat rates of more than 2000 m thick younger dryas yd fjord glaciers in western norway using a detailed chronology of 10 be exposure ages from lateral moraines and 14 c dated end moraines a primary conclusion is that ice margins retreated up the 120 170 km long fjords at mean rates of 240 340 m yr 1 during the early holocene we further show that part of the south western sector of the scandinavian ice sheet collapsed in two distinct steps the first step occurred between 19 5 and 18 5 ka bp as break up of the norwegian channel ice stream which drained the ice sheet during the last glacial maximum lgm the second step was the rapid retreat up the fjords mentioned above dated to 11 6 11 1 ka bp during the intervening 7000 years no net retreat occurred despite oscillations of the ice margin this stepwise ice margin retreat strongly contrasts with the more monotonic decay of the ice sheet as a whole indicating that water depths set the pace for climate triggered ice margin retreat in this part of the ice sheet calving and melting of marine margins has dominated mass loss from modern ice sheets in recent decades however the mechanisms and long term 100 1000 yr rate of ice front retreat is less certain and empirical examples such as those given here may help in developing better numerical models

holocene cooling culminates in sea ice oscillations in fram strait a reconstruction of holocene sea ice conditions in the fram strait provides insight into the palaeoenvironmental and palaeoceanographic development of this climate sensitive area during the past 8500 years bp organic geochemical analyses of sediment cores from eastern and western fram strait enable the identification of variations in the ice coverage that can be linked to changes in the oceanic and atmospheric circulation system by means of the sea ice proxy ip25 phytoplankton derived biomarkers and ice rafted detritus ird increasing sea ice occurrences are traced along the western continental margin of spitsbergen throughout the holocene which supports previous palaeoenvironmental reconstructions that document a general cooling a further significant ice advance during the neoglacial is accompanied by distinct sea ice fluctuations which point to short term perturbations in either the atlantic water advection or arctic water outflow at this site at the continental shelf of east greenland the general holocene cooling however seems to be less pronounced and sea ice conditions remained rather stable here a major neoglacial increase in sea ice coverage did not occur before 1000 years bp phytoplankton ip25 indices pip25 index are used for more explicit sea ice estimates and display a mid holocene shift from a minor sea ice coverage to stable ice margin conditions in eastern fram strait while the inner east greenland shelf experienced less severe to marginal sea ice occurrences throughout the entire holocene highlights biomarker and ird data give insight into holocene sea ice conditions in fram strait we find increasing sea ice coverage off west spitsbergen throughout the holocene oceanic atmospheric variability caused neoglacial sea ice fluctuations ice conditions along east greenland shelf remain rather stable until 1000 years bp

palaeomagnetism and isotopic age data from upper cretaceous igneous rocks of w portugal geological correlation and plate tectonic aspects summary palaeomagnetic results and k ar age data for the sintra and sines intrusive complexes w portugal and further details on the palaeomagnetic structure of the lisbon volcanics are reported the sintra complex consists of two main intrusive phases having been emplaced in the upper cretaceous at around 90 ma and 75 ma respectively the radiometric results show that the sines complex formed concurrently with the second sintra magmatism the early main sintra pluton has a characteristic magnetization of d 358 i 27 95 3 3 this remanence direction is defined by gabbros and diorites as the granitic rocks constituting the bulk of the complex are shown to possess stable secondary magnetization imposed during quaternary weathering the characteristic magnetization of the younger intrusive event as defined by the sines rocks has a mean direction of d 041 i 41 95 3 3 these two upper cretaceous palaeomagnetic directions are significantly different at the 95 per cent probability level the lisbon volcanics show the presence of the 75 ma magnetization suggesting that also this volcanic complex dates from the upper cretaceous in addition the palaeomagnetic results from the lisbon complex have given further substance to a previously reported magnetization component with shallow inclination and north northwest declination now defined by d 333 i 14 95 7 4 it is inferred that this magnetization which has a dual polarity structure formed through low temperature oxidation in late cretaceous to lower tertiary time the declination difference between the 90 ma and 75 ma magnetizations may be interpreted in terms of a two phase rotation of iberia in the upper cretaceous prior to the assumed late cretaceous early tertiary secondary magnetic imprint implying a counterclockwise rotation of minimum 40 followed by a clockwise rotation of similar magnitude however if the relevant palaeomagnetic reference frame for iberia before and after its independent tectonic movements in the late cretaceous is the african plate then the clockwise rotation is about 20 larger than the counterclockwise one apparently accounting for the compressive tectonism in the bay of biscay

reconstruction of glacier variability from lake sediments reveals dynamic holocene climate in svalbard abstract the arctic is warming faster than anywhere else on earth holocene proxy time series are increasingly used to put this amplified response in perspective by understanding arctic climate processes beyond the instrumental period however available datasets are scarce unevenly distributed and often of coarse resolution glaciers are sensitive recorders of climate shifts and variations in rock flour production transfer this signal to the lacustrine sediment archives of downstream lakes here we present the first full holocene record of continuous glacier variability on svalbard from glacier fed lake hajeren this reconstruction is based on an undisturbed lake sediment core that covers the entire holocene and resolves variability on centennial scales owing to 26 dating points a toolbox of physical geochemical xrf and magnetic proxies in combination with multivariate statistics has allowed us to fingerprint glacier activity in addition to other processes affecting the sediment record evidence from variations in sediment density validated by changes in ti concentrations reveal glaciers remained present in the catchment following deglaciation prior to 11 300 cal bp culminating in a holocene maximum between 9 6 and 9 5 ka cal bp correspondence with freshwater pulses from hudson strait suggests that early holocene glacier advances were driven by the melting laurentide ice sheet lis we find that glaciers disappeared from the catchment between 7 4 and 6 7 ka cal bp following a late hypsithermal glacier reformation around 4250 cal bp marks the onset of the neoglacial supporting previous findings between 3380 and 3230 cal bp we find evidence for a previously unreported centennial scale glacier advance both events are concurrent with well documented episodes of north atlantic cooling we argue that this brief forcing created suitable conditions for glaciers to reform in the catchment against a background of gradual orbital cooling these findings highlight the climate sensitivity of the small glaciers studied which rapidly responded to climate shifts the start of prolonged neoglacial glacier activity commenced during the little ice age lia around 700 cal bp in agreement with reported advances from other glaciers on svalbard in conclusion this study proposes a three stage holocene climate history of svalbard successively driven by lis meltwater pulses episodic atlantic cooling and declining summer insolation

variations in temperature and extent of atlantic water in the northern north atlantic during the holocene we compare six high resolution holocene sediment cores along a s n transect on the norwegian svalbard continental margin from ca 601n to 77 41n northern north atlantic planktonic foraminifera in the cores were investigated to show the changes in upper surface and subsurface water mass distribution and properties including summer sea surface temperatures sst the cores are located below the axis of the norwegian current and the west spitsbergen current which today transport warm atlantic water to the arctic sediment accumulation rates are generally high at all the core sites allowing for a temporal resolution of 10 10 2 years sst is reconstructed using different types of transfer functions resulting in very similar sst trends with deviations of no more than 71 0 1 51c a transfer function based on the maximum likelihood statistical approach is found to be most relevant the reconstruction documents an abrupt change in planktonic foraminiferal faunal composition and an associated warming at the younger dryas preboreal transition the earliest part of the holocene was characterized by large temperature variability including the preboreal oscillations and the 8 2 k event in general the early holocene was characterized by ssts similar to those of today in the south and warmer than today in the north and a smaller s n temperature gradient 0 231c 1n compared to the present temperature gradient 0 461c 1n the southern proxy records 60 691n were more strongly influenced by slightly cooler subsurface water probably due to the seasonality of the orbital forcing and increased stratification due to freshening the northern records 72 77 41n display a millennial scale change associated with reduced insolation and a gradual weakening of the north atlantic thermohaline circulation thc the observed northwards amplification of the early holocene warming is comparable to the pattern of recent global warming and future climate modelling which predicts greater warming at higher latitudes the overall trend during mid and late holocene was a cooling in the north stable or weak warming in the south and a maximum s n sst gradient of ca 0 71c 1n at 5000 cal years bp superimposed on this trend were several abrupt temperature shifts four of these shifts dated to 9000 8000 5500 3000 and 1000 and 400 cal years bp appear to be global as they correlate with periods of global climate change in general there is a good correlation between the northern north atlantic temperature records and climate records from norway and svalbard r 2007 elsevier ltd all rights reserved

global characterization of the holocene thermal maximum we analyze the global variations in the timing and magnitude of the holocene thermal maximum htm and their dependence on various forcings in transient simulations covering the last 9000 years 9 ka performed with a global atmosphere ocean vegetation model in these experiments we consider the influence of variations in orbital parameters and atmospheric greenhouse gases and the early holocene deglaciation of the laurentide ice sheet lis considering the lis deglaciation we quantify separately the impacts of the background melt water fluxes and the changes in topography and surface albedo in the analysis we focus on the intensity of the maximum temperature deviation relative to the preindustrial level its timing in the holocene and the seasonal expression in the model the warmest htm conditions are found at high latitudes in both hemispheres reaching 5 c above the preindustrial level while the smallest htm signal is seen over tropical oceans less than 0 5 c this latitudinal contrast is mostly related to the nature of the orbitally forced insolation forcing which is also largest at high latitudes and further enhanced by the polar amplification the holocene timing of the htm is earliest before 8 ka bp in regions not affected by the remnant lis particularly nw north america e asia n africa n south america the middle east ne siberia and australia compared to the early holocene insolation maximum the htm was delayed by 2 3 ka over ne north america and regions directly downwind from the lis a similar delay is simulated over the southern ocean while an intermediate lag of about 1 ka is found over most other continents and oceans the seasonal timing of the htm over continents generally occurs in the same month as the maximum insolation anomaly whereas over oceans the htm is delayed by 2 3 months exceptions are the oceans covered by sea ice and north africa were additional feedbacks results in a different seasonal timing the simulated timing and magnitude of the htm are generally consistent with global proxy evidence with some notable exceptions in the mediterranean region sw north america and eastern eurasia 2012 elsevier ltd

water deficient mylonite zones an example from the pyrenees abstract some mylonite zones which operate at retrograde conditions in metamorphic rocks have a low water content of the metamorphic fluid resulting in an incomplete reequilibration of the mineral assemblages recognition of such zones is important for a correct assessment of p t conditions of deformation especially where these data are used for reconstructing palaeogeometry of exhumed normal fault and thrust zones an example of a water deficient mylonite zone from the pyrenees is characterized by incomplete breakdown of sillimanite orthoclase in the stability field of muscovite quartz pure co 2 fluid inclusions limited postkinematic grain growth and high differential stresses during the deformation as indicated by recrystallized quartz grain size

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

holocene vegetational history and climatic change in west spitsbergen plant macrofossils from skardtjorna an arctic lake macrofossil analyses of a 335 cm long core from skardtjorna a small lake on the west coast of spitsbergen svalbard are presented the known processes of deposition of plant remains to arctic lake sediments are summarised and used in the interpretation of the vegetation history at skardtjorna the basal sediment is ams dated to 8110 110 bp the rest of the profile is dated by palaeomagnetic correlation the lowest sediments have the greatest macrofossil concentration and numbers of taxa per sample the occurrences of cassiope hypnoides and salix cf glauca before 4000 bp indicate a mean july temperature for the early holocene about 2 c higher than today comparable to the cassiope tetragona vegetation zone of the mid arctic region of the inner fjords increasing climatic severity resulted in the threshold from the cassiope to the dryas vegetation zone being passed at about 2500 bp the inferred climatic history at skardtjorna is compatible with other evidence from svalbard and elsewhere in the arctic

the last interglacial glacial period on spitsbergen svalbard the glaciation history of svalbard 78 n and the nw barents sea is reconstructed for the last 130 ka based on studies of sediments exposed in coastal cliffs at the head of isfjorden four different till beds separated by marine sediments are recognized the lowest marine formation containing mytilus edulis reflects warmer conditions than at present and is correlated with the last interglacial the eemian of europe and oxygen isotope substage 5e in the deep sea the post eemian tills are inferred to represent major glaciations around 110 ka bp 75 50 ka bp and 25 10 ka bp during the intervening intervals the glaciers on svalbard were not significantly larger than at present and the nw barents sea was probably ice free the ice free periods named phantomodden and kapp ekholm interstadials lasted from about 110 to 75 and from 50 to 25 ka bp respectively the marine fauna from both these interstadials indicate seasonally ice free conditions the ages of the recorded glaciations coincide with or are slightly younger than periods with insolation minima which at this latitude is determined by a low tilt of the earth s axis thus we postulate that the quaternary glaciations of svalbard were driven by orbital variations with the 41 ka tilt period in contrast to the lower latitude glaciations of scandinavia that were partly driven by the precession cycle with a periodicity of around 23 ka