tracking holocene glacial and high altitude alpine environments fluctuations from minerogenic and organic markers in proglacial lake sediments lake blanc huez western french alps holocene palaeoenvironmental evolution and glacial fluctuations at high altitude in the western french alps are reconstructed based on a multiproxy approach within lake blanc huez 2550 m a s l drainage basin the combination of seismic profiling 3 5 khz piston coring and radiocarbon dating in proglacial lacustrine sediments together with a detailed organic analysis of autochthonous and allochthonous supply allows documenting the evolution of glacier activity during the holocene over the last 9700 years the holocene lake record has a bimodal pattern whose transition is progressive and occurring between 5400 and 4700 cal bp during the early holocene the organic lacustrine facies reflects reduced glacial activity in the catchment this major glacial retreat seems to result from solar forcing and high summer insolation after 5400 cal bp lacustrine sedimentation is marked by the gradual increase both of minerogenic supply and soil erosion suggesting a progressive transition to wetter climatic conditions this climate change is synchronous both from the gradual decrease of summer insolation and the gradual reorganization of oceanic and atmospheric circulations characterizing the beginning of the neoglacial period both colder temperature and humid climate induced significant glacier advance since 4700 cal bp over this global trend three periods are particularly associated with higher runoff processes and higher soil erosion interpreted as wetter time intervals resulting from enhanced northern westerlies regimes across the north atlantic and western europe they are dated from 8700 to 7000 4700 to 2500 and 1200 to 200 cal bp these wetter phases drastically contrast with periods of reduced glacial activities dated from the early bronze age ca 3870 3770 cal bp the iron age ca 2220 2150 cal bp the roman period ca ad115 330 and the medieval warm period ca ad760 1160 in addition these dryer periods are associated with mining activities at high altitude

reconstructing recent environmental changes from proglacial lake sediments in the western alps lake blanc huez 2543 m a s l grandes rousses massif france abstract the evolution of high altitude glaciers and human activities in the grandes rousses massif is documented by high resolution seismic reflection profiling and multiproxy analysis of short sediment cores in proglacial lake blanc huez these lacustrine data are compared with historical chronicles geomorphological features and glaciological studies in this region of the western alps and they allow the documentation of recent environmental changes the specific geometry of high amplitude reflections in the uppermost seismic unit the lithology of short cores and the available limnological data in the lake suggest that clastic particles eroded by the glaciers and transported in suspension by glacial melt waters in early summer essentially develop homopycnal flood events in the lake a conceptual model linking fluctuations of glacier equilibrium line altitudes in the catchment area with sedimentary facies retrieved in the lake basin is proposed this approach allows reconstructing continuous glacier fluctuations since ad1820 1850 and suggests several phases of glacier fluctuations during the little ice age lia these reconstructions are based on changes in lacustrine sediment laminations density magnetic susceptibility reflectance spectra organic matter and arsenic content the age depth model of short sediment cores is provided by 210 pb 137 cs and 241 am radionuclide dating this chronology is further supported by identifying in lacustrine sediments the impact of i the nearby m 5 3 correncon earthquake in ad 1962 ii the development of the ski resort at high altitude close to the lake and iii the last advance of glaciers during the lia in ad1820 1850 and the following phase of glacier retreat observed in the alpine region at the end of the lia in ad 1880 frequent sandy layers enriched in organic matter and associated with fluctuations in the arsenic concentrations may result from hydraulic remobilisation of middle age mine tailings at the lake shore by snow melt or heavy rain fall events during the lia

lithofacies microfacies and depositional environments of upper cretaceous oceanic red beds chuangde formation in southern tibet the gyangze basin located in southern tibet is one of the representative areas for cretaceous oceanic red beds corbs we investigated and inter correlated several new corb outcrops in the western and southeastern part of the gyangze area in addition to the previously described chuangde section the corbs in the gyangze basin mainly consist of shales thin bedded marls re sedimented limestones and clasts supported conglomerates breccias planktonic foraminifers in the carbonate rocks within corbs belong to the globotruncana ventricosa and globotruncanita calcarata zones indicative of middle campanian age the facies assemblages in the different sections indicate that the depositional environments of corbs range from outer base of slope apron to basin zones within carbonates we observed microfacies types characteristic of basin open deep shelf margin or toe of slope environments gravity transport resulted from the steepening of the sea floor in the gyangze basin owing to subduction during the campanian relatively oxic bottom water conditions prevailed below the toe of slope environment in the gyangze basin during corb deposition however the presence of gray clasts within a multicoloured matrix suggests less oxic conditions at shallower water depths within the basin c 2010 elsevier b v all rights reserved

mid cretaceous oceanic red beds in the umbria marche basin central italy constraints on paleoceanography and paleoclimate abstract detailed studies of the mid cretaceous sedimentary strata in the umbria marche basin in italy revealed that aside from several well known organic rich black shale horizons that record oaes several varicolored mainly reddish horizons indicate oxic conditions at the ocean bottom eight such horizons have been identified in aptian cenomanian sequences in the umbria marche basin the dysoxic oxic beds alternate regularly but not cyclically and seem to be the result of non random processes their occurrence is not a completely random process the duration of deposition of these oceanic red beds orbs varies from 0 13 my orb4 recorded in the ticinella primula zone to 4 54 my for orb1 which spans the globigerinelloides ferreolensis zone to the ticinella bejaouaensis zone in the piobbico core mid cretaceous orbs are not a local phenomenon because they occur in the tethyan deposits in the southern and austrian alps the carpathians the northern caucasus the central north atlantic in northeastern england and in the western himalayas they provide evidence for periodic changes in redox conditions at the ocean bottom such changes could have been caused by changes in bioproductivity basin geometry sedimentation rates paleocirculation and or production of bottom waters with higher content of dissolved oxygen in response to changes in paleoclimate we suggest that the periodic inflow of colder more oxygenated bottom waters was the probable cause of orbs development either as a result of changes in the ocean bottom topography or as a result of brief cool climate periods however reliable proxies for changes in deep ocean circulation are still lacking if orbs were the result of the paleoclimate and therefore indirectly caused by changes in co2 in atmosphere they document the increased sensitivity and instability of the mid cretaceous climate thus changes in ocean dynamics were on a scale of several hundred thousand years to several million years which has not been considered by most theories of co2 cycling mid cretaceous greenhouse paleoclimate and paleocean dynamics

instruments and methods glaciological and volumetric mass balance measurements error analysis over 51 years for glacier de sarennes french alps the mass balance of glacier de sarennes french alps has been measured since 1949 using the glaciological method based on core and ablation stake data and area extrapolations to find the overall glacier balance the cumulative balance obtained in this way is very dependent on systematic errors that can increase linearly with the number n of measurement years whereas random errors rise with the volumetric balance method based on aerial photogrammetry provides results whose errors do not depend on the number of years this method was used to test field measurements for the period 1952 2003 and gives a mass balance of 32 30 1 04 m w e compared to 34 89 1 15 m w e based on field data the discrepancy between the two methods is discussed on the basis of a careful error analysis moreover the possibility of using the volumetric method to detect biases in field measurements is evaluated in terms of two types of errors the number and locations of measurement sites required to account for all the spatial and temporal variabilities of the mass balance is discussed by variance analysis methodological implications and recommendations are presented to provide mass balance measurements of the best possible accuracy

palaeomagnetism of cretaceous to tertiary sediments from southern tibet evidence for the extent of the northern margin of india prior to the collision with eurasia abstract palaeomagnetic studies have been carried out on mid cretaceous to latest palaeocene sediments from the tethyan himalaya on the northern margin of the indian plate near the localities of gamba 28 3 n 88 5 e and duela 28 0 n 89 2 e in southern tibet a total of 61 sites more than 700 cores have been sampled mainly from limestones zongshan formation jidula formation member ii zongpu formation sandstones jidula formation member iii and graywackes gamba group member ii with ages well defined from detailed lithological and biostratigraphic analyses carriers of characteristic remanences are magnetite in limestones and graywackes and hematite in sandstones reliable palaeodirections were obtained from 35 sites 356 specimens positive fold tests antiparallel normal and reverse polarities a northward trend of the palaeolatitudes with decreasing age and absence of any metamorphic overprint indicate a primary origin for the characteristic remanences the results have been compared with expected palaeodirections according to available data for the indian subcontinent based on its present day geometry the late maastrichtian sites fourteen sites 156 specimens and the middle late palaeocene sites fourteen sites 113 specimens yield palaeolatitudes of 5 7 s and 4 0 n for the sampling localities in southern tibet respectively these palaeolatitudes are much further north than expected and imply that crustal shortening between the tethyan himalaya and the indian shield since the time of india eurasia collision has occurred on the order of 1500 km at the longitude of gamba duela comparison of our observed palaeolatitudes with palaeolatitudes for the lhasa block during cretaceous and palaeocene times indicate that initial contact of the northern indian margin with the lhasa block was already established at 65 60 ma with suturing completed at about 55 50 ma

reanalysis of the us geological survey benchmark glaciers long term insight into climate forcing of glacier mass balance mountain glaciers integrate climate processes to provide an unmatched signal of regional climate forcing however extracting the climate signal via intercomparison of regional glacier mass balance records can be problematic when methods for extrapolating and calibrating direct glaciological measurements are mixed or inconsistent to address this problem we reanalyzed and compared long term mass balance records from the us geological survey benchmark glaciers these five glaciers span maritime and continental climate regimes of the western united states and alaska each glacier exhibits cumulative mass loss since the mid 20th century with average rates ranging from 0 58 to 0 30 m w e a 1 we produced a set of solutions using different extrapolation and calibration methods to inform uncertainty estimates which range from 0 22 to 0 44 m w e a 1 mass losses are primarily driven by increasing summer warming continentality exerts a stronger control on mass loss than latitude similar to elevation topographic shading snow redistribution and glacier surface features often exert important mass balance controls the reanalysis underscores the value of geodetic calibration to resolve mass balance magnitude as well as the irreplaceable value of direct measurements in contributing to the process based understanding of glacier mass balance

positive degree day factors for ablation on the greenland ice sheet studied by energy balance modelling ice ablation is related to air temperature by the positive degree day factor variations of the positive degree day factor in west greenland are studied using an energy balance model to simulate ablation under different conditions degree day factors for simulated and measured ice ablation at nordbogletscher and qaman rssup sermia agree well with values around 8 mm d 1 c 1 degree day factors for snow are less than half those for ice energy balance modelling shows that degree day factors vary with summer mean temperature surface albedo and turbulence but there is only evidence of large positive degree day factors at lower temperatures and with low albedo 0 3 the greatest effect of albedo variations 0 3 0 7 is at lower temperatures while variations in turbulence have greater effect at higher temperatures current models may underestimate runoff from the greenland ice sheet by several tenths because they use a degree day factor for melting ice that is too small for the colder parts of the ice sheet i e the upper ablation area and the northerly margin

isotopic spikes from tropical cyclones in surface waters opportunities in hydrology and paleoclimatology abstract the stable isotopic ratio of precipitation from tropical cyclones is very low compared to that of normal summer precipitation lawrence and gedzelman 1996 tropical storms allison and chantal made landfall in southeast texas in the summer of 1989 and dumped large amounts of rain isotope ratios of surface waters measured at five different sites decreased markedly after the passage and remained low for a few weeks the return of isotope values to normalcy following these storms varied from site to site reflecting differences among the hydrological environments during other summers from 1985 to 1993 isotope ratios of rains were higher and in the normal range calculations using air temperatures and oxygen isotope measurements of the surface waters show that organically precipitated fresh water carbonate should have recorded the two oxygen isotopic spikes produced by allison and chantal at all five sites this suggests that isotopic analysis of ancient fresh water fossil carbonate shells fossil mammal teeth or tree rings might be used to document past tropical cyclone activity

climate change on the yucatan peninsula during the little ice age we studied a 5 1 m sediment core from aguada x caamal 20 36 6 n 89 42 9 w a small sinkhole lake in northwest yucatan mexico between 1400 and 1500 a d oxygen isotope ratios of ostracod and gastropod carbonate increased by an average of 2 2 and the benthic foraminifer ammonia beccarii parkinsoniana appeared in the sediment profile indicating a hydrologic change that included increased lake water salinity pollen from a core in nearby cenote san jose chulchaca showed a decrease in mesic forest taxa during the same period oxygen isotopes of shell carbonate in sediment cores from lakes chichancanab 19 53 0 n 88 46 0 w and salpeten 16 58 6 n 89 40 5 w to the south also increased in the mid 15th century but less so than in aguada x caamal climate change in the 15th century is also supported by historical accounts of cold and famine described in maya and aztec chronicles we conclude that climate became drier on the yucatan peninsula in the 15th century a d near the onset of the little ice age lia comparison of results from the yucatan peninsula with other circum caribbean paleoclimate records indicates a coherent climate response for this region at the beginning of the lia at that time sea surface temperatures cooled and aridity in the circum caribbean region increased

an 11 year record of mass balance of brewster glacier new zealand determined using a geostatistical approach recognising the scarcity of glacier mass balance data in the southern hemisphere a mass balance measurement programme was started at brewster glacier in the southern alps of new zealand in 2004 evolution of the measurement regime over the 11 years of data recorded means there are differences in the spatial density of data obtained to ensure the temporal integrity of the dataset a new geostatistical approach is developed to calculate mass balance spatial co variance between elevation and snow depth allows a digital elevation model to be used in a co kriging approach to develop a snow depth index sdi by capturing the observed spatial variability in snow depth the sdi is a more reliable predictor than elevation and is used to adjust each year of measurements consistently despite variability in sampling spatial density the sdi also resolves the spatial structure of summer balance better than elevation co kriging is used again to spatially interpolate a derived mean summer balance index using sdi as a co variate which yields a spatial predictor for summer balance the average glacier wide surface winter summer and annual balances over the period 2005 15 are 2484 2586 and 102 mm w e respectively with changes in summer balance explaining most of the variability in annual balance

new oxygen isotope evidence for long term cretaceous climatic change in the southern hemisphere a new composite 18 o record generated from calcareous fine fraction and bulk sediments from the exmouth plateau details long term cretaceous climatic change at mid latitudes in the southern hemisphere assessment of new and previously published 18 o data indicates that a mid cretaceous global climatic optimum was achieved sometime between the time of the cenomanian turonian boundary and the middle turonian when surface ocean paleotemperatures were the highest of the past 115 m y periods of cooling and warming that reversed the general patterns were superimposed on long term aptian turonian warming and turonian maastrichtian cooling trends respectively extrapolation of southern hemisphere paleotemperature trends to maastrichtian paleotemperature data from a low latitude pacific guyot implies that maximum mid cretaceous low latitude paleotemperatures could have been in excess of 33 c

carbonate apron models alternatives to the submarine fan model for paleoenvironmental analysis and hydrocarbon exploration sediment gravity flow deposition along the deep water flanks of carbonate platforms typically does not produce submarine fans rather wedge shaped carbonate aprons develop parallel to the adjacent shelf slope break the major difference between submarine fans and carbonate aprons is a point source with channelized sedimentation on fans versus a line source with sheet flow sedimentation on aprons two types of carbonate aprons may develop along relatively gentle 4 platform margin slopes aprons form immediately adjacent to the shallow water platform and are referred to as carbonate slope aprons along relatively steep 4 15 platform margin slopes redeposited limestones accumulate in a base of slope setting by passing an upper slope via a multitude of small submarine canyons and are referred to as carbonate base of slope aprons both apron types are further subdivided into inner and outer facies belts inner apron sediments consist of thick mud supported conglomerates and megabreccias facies f as well as thick coarse grained turbidites facies a interbedded with subordinate amounts of fine grained peri platform ooze facies g outer apron sediments consist of thinner grain supported conglomerates and turbidites facies a as well as classical turbidites facies c with recognizable bouma divisions interbedded with approximately equal proportions of peri platform ooze facies g seaward aprons grade laterally into basinal facies of thin base cut out carbonate turbidites facies d that are subordinate to peri platform oozes facies g carbonate base of slope aprons grade shelfward into an upper slope facies of fine grained peri platform ooze facies g cut by numerous small canyons that are filled with coarse debris as well as intraformational truncation surfaces which result from submarine sliding in contrast slope aprons grade shelfward immediately into shoal water platform margin facies without an intervening by pass slope the two carbonate apron models presented here offer alternatives to the submarine fan model for paleoenvironmental analysis and hydrocarbon exploration for mass transported carbonate facies

low stable isotope ratios of tropical cyclone rains tropical cyclone rains have distinctly lower stable isotope ratios than rains in other tropical and summer precipitation systems with a mean value slightly above that of water vapor near the sea surface the isotope ratios also decrease radially inward to the eye wall but appear to be anomalously low even near the periphery of the rain shield these findings indicate that tropical cyclones are highly efficient precipitation systems and suggest the use of stable isotope ratios as dynamic tracers of a tropical cyclone s water and energy budgets

using upper air conditions to estimate south cascade glacier washington u s a summer balance asimplemodelusesonce dailymeteorologicalvaluesintheu s national centers for environmental predictionand u s national center foratmospheric research ncep ncar re analysis databaseto estimate summerbalanceof south cascade glacier washington u s a each year over1959 99 the rms error 0 30mw e r 2 0 71 is com parable to measurement error the model relates summer balance linearly to temperature t 0 c at 2000m and to snow flux at1650m the altitudes in recent years of the equilib rium line and terminus the snow flux is the product of the humidity and westerly wind component at 850hpa when temperature t 2 c at 1650m temperatures are inter polated linearly betweenthe 850 and 700hpa levels boththe positive 2000mtemperature andthe snow flux are summedfrom 26 aprilto 4 october whenthe summerestimatesare combinedwiththosefromawinterbalancemodelusingthesamedatabase thermserrorin estimating netbalance is 0 40m r 2 0 81 the indicated sensitivities of balance to warm ing of 1 c are 0 51m for summerand 0 24m for winter onthe assumptionthatthetotal 0 75m c 1 sensitivityexists atall altitudes awarmingof only 0 7 c wouldbe sufficientto overcome the1986 98 averagenetbalance 0 5matthe top of theglacier

long term change of mass balance and the role of radiation the effect of climate change in the 20th century is investigated based on measured mass balance data annual winter and summer mass balances on claridenfirn switzerland since 1914 15 storglaciaren sweden since 1945 46 storbreen norway since 1948 49 glacier de sarennes france since 1948 49 and vernagtferner austria since 1965 66 are studied with air temperature at high altitude stations and the longest records of solar global radiation in europe the mean mass balances of these glaciers during the 20th century were mostly negative except for the first two decades the fluctuating mass balance reaches the minimum largest loss and maximum almost equilibrium around 1940 and 1980 respectively with a drastic loss in the last 15 years these variations are mostly steered by the variation in summer mass balance the change in the summer mass balance is determined to 72 by temperature and the remaining 28 by solar radiation during the colder period e g 1960 80 the reduction in solar radiation counteracted the warming trend due to the greenhouse effect since 1990 the greenhouse effect of terrestrial radiation and the global brightening effect of solar radiation have both been acting to accelerate the melt resulting in the unprecedented mass loss of the observational era the glacier mass balance during the 20th century clearly reacted towards temperature and solar radiation changes which reflected the greenhouse effect and aerosol and cloud variations

passage of tropical storm allison 2001 over southeast texas recorded in δ18o values of ostracoda freshwater ostracoda collected in ephemeral pond waters derived from tropical storm allison 2001 texas recorded the unusually low oxygen isotope values of that storm therefore the potential clearly exists in locations where tropical cyclones make landfall to obtain a long term record of tropical cyclone activity from fossil ostracode calcite

errors in daily ablation measurements in northern greenland 1993 94 and their implications for glacier climate studies ablation climate studies were made at two locations in northern green land in the summers of 1993 and 1994 respec tively daily ablation ii as measured at ten stakes within a small area and the data were compared with each other to detect gross errors for example high deviations for data taken on the same day or low cor rela tions between data series at differ ent stakes indicate erroneous data a fter cl iscard i ng data for one stake in 1993 and t wo stakes in 1994 random errors in daily ablation data for individ ual stakes arc 5 kg m 2 d i which is further reduced to only about 2 kg m 2 d 1 by averag ing over eight or nine stakes random errors in cal culated energy bala nces using the pres ent abla tion data are much imover than found in earlier studies in vest greenland where ablation was only measured on three stakes without any attem pt to detect gross errors aside from day to day errors there arc 10 diffe rences in mca n ablation at different sta kes which are probably caused by small s cal e variations in surface albedo such inters take diffe rences gi e 10 uncertainty in positive degree day faetors which arc 9 8 0 9 and 5 9 0 6 kg m 2 d 1 deg 1 for the two sites

dynamic behaviour analysis of glacier de saint sorlin france from 40 years of observations 1957 97 mass balance and dynamic measurements carried out on glacier de saint sorlin since 1957 provide a good opportunity to study the dynamics of this glacier ice flow analysis shows that dynamic changes have been important over the last 40 years and that these changes are not consistent with the concepts usually used in glacier modelling present velocities are larger than the 1960 velocities although the thickness decreased everywhere 10 30 m in the ablation zone a simple numerical ice flow model which does not include longitudinal stress gradients has been used to investigate these phenomena this model allows us to infer the sliding velocity from observed surface and calculated deformation velocities we conclude that 1 the sliding velocity cannot be described by weertman analysis or empirical relations which link the sliding to the thickness and surface slope 2 the inferred sliding velocity is uniform over at least half of the glacier and 3 there is no clear link between the sliding process and the quantity of water coming from surface ablation furthermore it may not be reasonable to calibrate model flow parameters from geometry changes because the surface geometry is relatively insensitive to velocity changes over some decades

contribution of glacier runoff to water resources of la paz city bolivia 16 s the supply of glacier water to la paz city bolivia between 1963 and 2006 was assessed at annual and seasonal timescales based on the mass balance quantification of 70 glaciers located within the drainage basins of la paz glaciers contributed 15 of water resources at an annual scale 14 in the wet season 27 in the dry season uncertainties in our estimation are related to the assumed constant precipitation 0 5 for ice free areas and up to 6 5 for glaciated areas the constant runoff coefficient 1 the surface areas of the glaciers and catchments 5 and the mean mass balance uncertainty of the 21 glaciers used to obtain the mass balance of the 70 glaciers 12 of the total discharge despite the loss of 50 of the glacierized area during the study period runoff at la paz did not change significantly showing that increase in ice melt rates compensated for reduction in the surface area of the glaciers in the future assuming complete disappearance of the glaciers and no change in precipitation runoff should diminish by 12 at an annual scale 9 during the wet season and 24 during the dry season

sedimentary history of the tethyan basin in the tibetan himalayas after an epicontinental phase the sedimentary rocks in the tibetan himalayas document a complete wilson cycle of the neo tethyan tethys ill evolution between the gondwana supercontinent and its northward drifting margin lhasa block from the late permian to the eocene during the triassic rift stage the basin was filled with a huge clastic dominated sediment wedge with up to 5 000 m of flysch in the northern zone widespread deltaic clastics and shallow water carbonates of late norian to earliest jurassic age in the southern zone mark in conjunction with decreasing tectonic subsidence the transition to the drift stage some 4 500 m of jurassic and early cretaceous shallow water carbonates and siliciclastics accumulated on the tethyan indian passive margin deepening upward sequences with condensed beds at their tops alternate with repeated progradational packages of shelf sediments extensive abyssal sediments with basaltic volcanics in the northern deep water zone reflect continued ocean spreading and thermal subsidence paleomagnetic data gained separately for the northern indian plate and the lhasa block indicate that the neo tethys reached its maximum width about 110 ma ago with a spreading rate of 4 8 cm year before it commenced to close again during the remnant basin stage in the late cretaceous and paleogene a shallowing upward megasequence capped by a carbonate platform developed in the southern inner shelf realm in the northern slope basin plain zone turbidites and chaotic sediments derived from both the acretionary wedge and the steepening slope of the passive margin accumulated the depositional center of the remnant basin shifted southward as a result of flexural subsidence and southward overthrusting the sediments from the triassic to the paleogene are tentatively subdivided into five mega sequences which are controlled mainly by regional tectonics climatic influence e g carbonate deposition due to northward plate motion is partially subdued by terrigenous input and or increased water depth during the oligocene and miocene crustal shortening led to rapid uplift and the deposition of fluvial molasse in limited basins

meteorological controls on glacier mass balance empirical relations suggested by measurements on glacier de sarennes france glacial mass balance reconstruction for a long term time scale requires knowledge of the relation between climate change and mass balance fluctuations a large number of mass balance reconstructions since the beginning of the century are based on statistical relations between monthly meteorological data and mass balance the question examined in this paper is are these relationships reliable enough for long term time scale extrapolation from the glacier de sarennes long mass balance observations series we were surprised to discover large discrepancies between relations resulting from different time periods the importance of the albedo in relation to ablation and mass balance is highlighted and it is shown that it is impossible to ignore glacier surface conditions in establishing the empirical relation between mass balance fluctuations and climatic variation to omit this parameter leads to incorrect results for mass balance reconstruction in the past based on meteorological data

silver and lead in high altitude lake sediments proxies for climate changes and human activities abstract high altitude lake sediments are often used as archives for environmental changes and their chemical and isotopic compositions provide significant constraints on natural and anthropogenic long term changes that have occurred in their catchment area here trace element concentrations and pb isotopes are presented for two sedimentary cores from lake blanc huez in the french alps to trace the impact of climate changes and human activities over the holocene lead and ag contents are very high and clearly dominated by input from a pb ag vein located a few meters from the lakeshore a vein that also buffers the pb isotopes mining of this vein in medieval times is recorded in the corresponding lake sediments with high ag content coupled with high pb u ratio these chemical characteristics can be used to constrain the major holocene climate changes significant advances of glaciers next to the lake produced sediments with ag and pb concentration peaks and high pb u ratios due to accelerated erosion of the pb ag vein similar to the effects of the medieval mining in contrast reduced glacier activity led to the formation of organic rich sediments with high u and as contents and low pb u ratios more generally the observed combination of chemical changes could be used elsewhere to decipher environmental changes over long periods of time

combined textural and stable isotopic data as proxies for the mid cretaceous paleoclimate a case study of lacustrine stromatolites in the gyeongsang basin se korea abstract microbial interference of the prevailing sedimentary dynamics during stromatolite growth records vital biogeochemical information which reflects the prevailing paleoclimatic conditions this study documents the simultaneous geochemical and textural changes in mid cretaceous lacustrine stromatolites gyeongsang basin se korea deposited in a semi arid setting fibrous calcite micrite couplets in the stromatolites occurring in the sinyangdong hwasan and banyawol formations constitute the basic growth cycles and can be divided into first second and third order cycles second order cycles show couplets with gradual textural changes from fibrous calcite to micrite laminae and three different types of micrite are present sometimes one type of micrite evolves into another within the second order cycle in the sinyangdong stromatolites consistent enrichments in 18o and depletion in 13c towards micrites within the sinyangdong and hwasan stromatolite couplets and a concomitant depletion of both isotopes from fibrous calcite to micrite in the banyawol sample can be observed these shifts reflect paleohydrological changes in the lake water related to paleoproductivity and paleosalinity fluctuations relatively higher paleosalinity values within the sinyangdong lake water system is registered by higher 18o values of fibrous calcite and micrite in the sy 3 than in the sy 1 and sy 2 stromatolites the consistent shifts in 18o and 13c isotopes in different textural growth fabrics indicate that paleohydrological factors could play a significant role in the formation of these primary lacustrine carbonates textural changes shown by the frequency of the growth cycles also corresponds with oxygen and carbon isotopic values these results appear to have been influenced by climate related paleohydrological changes

reconstructing 7000 years of north atlantic hurricane variability using deep sea sediment cores from the western great bahama bank q1 enso show abrupt changes around 6000 yrs b p but most coastal sedimentary records do not span this time period establishing longer records is essential for understanding mid holocene patterns of storminess and their climatic drivers which will lead to better forecasting of how climate change over the next century may affect tropical cyclone frequency and intensity storms are thought to be an important mechanism for transporting coarse sediment from shallow carbonate platforms to the deep sea and bank edge sediments may offer an unexplored archive of long term hurricane activity here we develop this new approach reconstructing more than 7000 years of north atlantic hurricane variability using coarse grained deposits in sediment cores from the leeward margin of the great bahama bank high energy event layers within the resulting archive are 1 broadly correlated throughout an offbank transect of multi cores 2 closely matched with historic hurricane events and 3 synchronous with previous intervals of heightened north atlantic hurricane activity in overwash reconstructions from puerto rico and elsewhere in the bahamas lower storm frequency prior to 4400 yrs b p in our records suggests that precession and increased nh summer insolation may have greatly limited hurricane potential intensity outweighing weakened enso and a stronger west african monsoon factors thought to be favorable for hurricane development

geochemical and climatic effects of increased marine organic carbon burial at the cenomanian turonian boundary perhaps the most significant event in the cretaceous record of the carbon isotope composition of carbonate1 2 other than the 1 2 5 negative shift in the carbon isotope composition of calcareous plankton at the cretaceous tertiary boundary3 is the rapid global positive excursion of 2 13c enrichment which took place between 91 5 myr and 90 3 myr late cenomanian to earliest turonian c t boundary event 1 4 5 this excursion has been attributed to a change in the isotope composition of the marine total dissolved carbon tdc reservoir resulting from an increase in rate of burial of 13c depleted organic carbon which coincided with a major global rise in sea level5 during the so called c t oceanic anoxic event oae 6 here we present new data from nine localities which demonstrate that a positive excursion in the carbon isotope composition of organic carbon at or near the c t boundary7 8 is nearly synchronous with that for carbonate and is widespread throughout the tethys and atlantic basins fig 1 as well as in more high latitude epicontinental seas the postulated increase in the rate of burial of organic carbon may have had a significant effect on co2 and o2 concentrations in the oceans and atmosphere and consequent effects on global climate and sedimentary facies

mass balance measurements problems and two new methods of determining variations les deux nouvelles methodes d analyse des bilans sont basees sur le modele lineaire de variation des bilans propose par lliboutry 1974 la premiere n utilise qu un systeme de mesures limitees a quelques sites fixes la seconde basee sur l equation de continuite permet d obtenir un bilan sur un secteur limite par deux profils transversaux ou ont ete mesures les altitudes et vitesses moyennes en surface

high altitude varve records of abrupt environmental changes and mining activity over the last 4000 years in the western french alps lake bramant grandes rousses massif abstract two twin short gravity cores and a long piston core recovered from the deepest part of proglacial lake bramant grandes rousses massif french alps under and overlying a large slump identified by high resolution seismic profile allow the investigation of holocene natural hazards and interactions between human activity and climatic changes at high altitude annual sedimentation throughout the cores glacial varves is identified on photographs itrax high resolution continuous microfluorescence x and cat scan computerized axial tomography analyses and is supported by 1 the number of dark and light laminations between dates obtained by radionuclide measurements 137cs 241am 2 the correlation of a slump triggered by the nearby ad 1881 allemond earthquake msk intensity vii and of a turbidite triggered by the ad 1822 chautagne regional earthquake msk intensity viii 3 the number of laminations between two accelerator mass spectrometry ams 14c dates and 4 archaeological data in lake bramant dark layers are coarser contain less detrital elements but more neoformed elements and organic matter content these darker laminations result from calm background sedimentation whereas the lighter layers are finer and rich in detrital elements and reflect the summer snowmelt traces of mining activity during the roman civilization apogee ad 115 330 and during the early bronze age 3770 3870 cal bp are recorded by lead and copper content in the sediments and probably result from regional and local mining activity in the nw alps warmer climate during the bronze age in this part of the alps is suggested by 1 two organic deposits 4160 3600 cal bp and 3300 2850 cal bp likely reflecting a lower lake level and smaller glaciers and 2 evidence of a different vegetation cover around 2500 m a s l the onset of clastic proglacial sedimentation between 3600 3300 cal bp and since 2850 cal bp is synchronous with periods of glacier advances documented in the alps and high lake levels in west central europe this major change in proglacial sedimentation highlights the development of a larger st sorlin glacier in the catchment area of lake bramant

iron rich carbonate tidal deposits angepena formation south australia a redox stratified cryogenian basin abstract the cryogenian angepena formation ca 650 ma of south australia records deposition in a peritidal environment equivalent to and landward of the balcanoona reef complex and offers valuable insights into shallow marine chemistry during the nonglacial interlude between two global ice ages the sedimentary facies comprise an iron rich marine red bed succession and include red mudcracked dolomitic shales tepee dolostone crossbedded intraclastic ooid grainstone and tepee related sheet cavities with marine cements these facies are interpreted to have been deposited in a cryogenian tidal flat to subtidal setting that is laterally equivalent to the reefal and back reef environments of the balcanoona formation marine cements from this environment are characterized by well preserved non and bright cathodoluminescent zoning and strong negative to slightly positive cerium ce anomalies ce ce we suggest that the angepena formation is indicative of intermittent synsedimentary iron oxide precipitation in an oxidized peritidal environment in an otherwise strongly ferruginous and anoxic oceanic setting large negative ce anomalies develop over a narrower depth range when compared to modern oxic marine settings highlighting the importance of dissolved mn and fe concentrations in controlling the magnitude of the negative ce anomalies overall coupled sedimentological and geochemical evidence suggest a neoproterozoic shallow marine system at the interface of an oxidizing atmosphere and an anoxic ferruginous marine system

a century reconstruction of the mass balance of glacier de sarennes french alps the 50 year time series of mass balance on glacier de sarennes is one of the longest in the french alps and so is often used as a reference for glacier variations in the french alps meteorological data can be used to extend the series backwards in time martin 1978 proposed such a reconstruction for the 1882 1977 period with 50 years of observations we show that the classical method used by martin is too dependent on the calibration period we therefore try to improve the accuracy of this reconstruction using the vincent and vallon 1997 method which takes into account the albedo change of the surface during the ablation period this is called the daily method this new method appears to be stable in time once calibrated the daily method is applied to reconstruct the 1881 1949 period the new reconstruction is compared to a volumetric balance between two maps from 1906 and 1981 it appears that both reconstructions classical and daily fail to render the trend correctly over a long period of time the cumulative centred mass balance correlates well r 2 0 62 with the hydrological mass balance series of aletschgletscher switzerland

altitudinal gradient of mass balance sensitivity to climatic change from 18 years of observations on glacier d argentiere france assessment of the contribution of small glaciers to sea level rise or the reconstruction of past glacial mass balance requires knowledge of mass balance sensitivity to climatic variations the aim of this paper is to clarify this relation the mass balance fluctuations analyzed from measurements on glacier d argentiere mont blanc massif france between 1850 and 2700 m a s l were compared with climatic variations at a nearby meteorological station statistical study of the data shows that 1 the annual mass balance fluctuations are dependent on elevation and 2 the mass balance sensitivity to temperature decreases with altitude and diverges from current model results consequences of a temperature variation of 1 c for global volume variations are significant a simple calculation on glacier des bossons mont blanc massif france shows that the sensitivity from the model can lead to volume variations twice as high as results compatible with our observations

comment on the species and age determination published by li et al discovery of radiolaria from upper cretaceous oceanic red beds in daba kangmar and its paleogeographic implication palaeogeography palaeoclimatology palaeoecology 312 2011 127 137 abstract li et al 2011a discovery of radiolaria from upper cretaceous oceanic red beds in daba kangmar and its paleogeographic implication palaeogeography palaeoclimatology palaeoecology 312 127 137 reported three radiolarian assemblages from cretaceous oceanic red beds corbs in chuangde formation which they assigned to the late cretaceous with only very few exceptions all species have been erroneously determined and consequently the age of the samples was wrongly interpreted none of these radiolarians suggest a late cretaceous age late santonian to early maastrichtian as proposed in the publication on the contrary all radiolarians are indicators of an early cretaceous age early barremian to earliest albian

masking of interannual climate proxy signals by residual tropical cyclone rainwater evidence and challenges for low latitude speleothem paleoclimatology 1 the anomalously low oxygen isotope ratio 18o values of tropical cyclone rainfall can transfer proxy information about past tropical cyclone activity to stalagmite oxygen isotope records isotopically distinct stormwater reaches the growing crystal surface as a coherent slug or after attenuation by mixing with isotopically normal vadose groundwaters a high resolution micromilled stalagmite stable isotope record from belize shows that residual tropical cyclone water from hurricane mitch masked the oxygen isotope record of a major el nino event on decadal time scales measured 18o values are affected by changes in local tropical cyclone frequency despite the tropical cyclone masking effect the structure of the missing el nino event is preserved in the atm 7 carbon isotope ratios 13c values in tropical cyclone prone regions the fidelity of stalagmite oxygen isotope proxy data to recording background climate signals is modulated by temporal variations in local tropical cyclone rainfall and the sensitivity of individual stalagmites to tropical cyclone masking varies with hydrology speleothem 13c values unaffected by tropical cyclones can preserve the underlying structure of climatic variability for low latitude speleothems with c o isotope covariance intervals in which the 18o values are significantly lower than 13c values predict may indicate periods when local tropical cyclone masking of isotope derived precipitation records is enhanced by greater infiltration of tropical cyclone rain the temporal structure in stalagmite c o isotope covariance has paleoenvironmental meaning that may be revealed by exploring factors associated with independent behavior in each isotope ratio respectively tropical cyclone masking presents new challenges to paleoclimatology and a source of hypotheses for paleotempestology

late holocene climate change for the eastern interior united states evidence from high resolution δ 18 o values of sagittal otoliths abstract stable oxygen isotope values were determined for freshwater drum aplodinotus grunniens sagittal otoliths recovered from the eastman rockshelter archaeological site in northeast tennessee to evaluate climate change for the eastern interior united states from 5500 calendar years ago to the present micromilled samples representing less than six days of otolith growth were extracted to acquire high resolution intra otolith variation in 18 o values freshwater drum sagittal otoliths form annual bands due to thermally induced growth cessation below 10 c 18 o h 2 o values can be calculated once a high resolution carbonate sample representing the beginning of the growing season is isolated maximum summer temperature can be calculated using the seasonal minimum 18 o caco 3 value and the 18 o h 2 o value maximum summer temperatures calculated from the freshwater drum sagittae suggest that summer temperatures generally decrease from 29 c at 5 5 ka to 22 c at 0 3 ka however warmer climates at 2 9 1 7 1 6 and 1 2 1 0 ka punctuate this trend a more complete picture of the climate is reconstructed because 18 o h 2 o values which are a function of the ratio of summer to winter precipitation are also calculated a relatively low average 18 o h 2 o value of 8 1 vsmow was calculated at 1 0 ka suggesting cold winters dry summers and or wet winters may have prevailed during part of the medieval warm period in tennessee contrary to studies suggesting that the holocene was extremely stable and the hypsithermal was invariably warm and dry additional evidence suggesting both significant climate variability and evidence for a wetter mid holocene is presented

testing coral based tropical cyclone reconstructions an example from puerto rico abstract complimenting modern records of tropical cyclone activity with longer historical and paleoclimatological records would increase our understanding of natural tropical cyclone variability on decadal to centennial time scales tropical cyclones produce large amounts of precipitation with significantly lower 18 o values than normal precipitation and hence may be geochemically identifiable as negative 18 o anomalies in marine carbonate 18 o records this study investigates the usefulness of coral skeletal 18 o as a means of reconstructing past tropical cyclone events isotopic modeling of rainfall mixing with seawater shows that detecting an isotopic signal from a tropical cyclone in a coral requires a salinity of 33 psu at the time of coral growth but this threshold is dependent on the isotopic composition of both fresh and saline end members a comparison between coral 18 o and historical records of tropical cyclone activity river discharge and precipitation from multiple sites in puerto rico shows that tropical cyclones are not distinguishable in the coral record from normal rainfall using this approach at these sites

common climatic signal from glaciers in the european alps over the last 50 years conventional glacier wide mass balances are commonly used to study the effect of climate forcing on glacier melt unfortunately the glacier wide mass balances are also influenced by the glacier s dynamic response investigations on the effects of climate forcing on glaciers can be largely improved by analyzing point mass balances using a statistical model we have found that 52 of the year to year deviations in the point mass balances of six glaciers distributed across the entire european alps can be attributed to a common variability point mass balance changes reveal remarkable regional consistencies reaching 80 for glaciers less than 10 km apart compared to the steady state conditions of the 1962 1982 period the surface mass balance changes are 0 85 m water equivalent w e a 1 for 1983 2002 and 1 63 m w e a 1 for 2003 2013 this indicates a clear and regionally consistent acceleration of mass loss over recent decades over the entire european alps

cretaceous oceanic red beds corbs different time scales and models of origin abstract the cretaceous oceanic red bed corb is a newly opened window on global oceanic and climate changes during the cretaceous greenhouse world as a result of the international geoscience programmes 463 494 and 555 2002 2010 corbs have been documented in many places by numerous publications the principle goal of this paper is to summarize scientific advances on corbs including chronostratigraphy sedimentology mineralogy elemental and isotopic geochemistry and their relationship to oceanic anoxic events oaes palaeoclimate and palaeoceanography we propose a new geochemical classification of the corbs using cao al 2 o 3 and sio 2 values which lithologically refer to marly clayey and cherty corbs respectively detailed mineralogical studies indicate that hematite goethite and mn 2 bearing calcite are the minerals imparting the red color of corbs hematite clusters of several to tens of nanometers in the calcite structure are the main cause of the red coloring of limestones and the mn 2 bearing calcite gives additional red color goethite was thought to form originally with hematite and was subsequently transformed to hematite during late diagenesis chronostratigraphic data allow the distinction of two groups of corbs by their durations short term corbs are generally less than 1 myr in duration and seem to be on the scale of milankovitch cycles during the deposition of cretaceous reddish intervals from odp cores 1049 and 1050 low primary productivity and relatively high surface temperature resulted in low organic carbon flux into the sediments which reduced oxygen demand and produced oxidizing early diagenetic conditions in such an oxic environment iron oxides formed imparting the reddish color the long term corbs depositional events lasted longer than 4 myr and may be a possible consequence of the oaes enhanced amounts of organic carbon and pyrite burial during and after the oaes would have resulted in a large and abrupt fall in atmospheric co 2 concentration which probably induced significant global climatic cooling during and after the oaes global cooling would have enhanced formation of cold deep water increasing its oxidizing capacity due to the greater content of dissolved oxygen and would promote formation of oceanic red beds sedimentological mineralogical and geochemical data indicate that corbs were deposited under highly oxic oligotrophic conditions probably at a low sedimentation rate the cretaceous red and white limestones from italy have similar compositions of terrestrial input sensitive elements al ti k mg rb zr higher contents of fe 2 o 3 and depleted redox sensitive elements v cr ni and u and micronutrient elements cu zn indicating similar provenance sources but red limestones were deposited under more oxic conditions at the sediment water interface than white limestones the cretaceous red shales such as those from the north atlantic and tibet have similar mineralogy and geochemistry as the late cenozoic red clays in the pacific ocean and the environment where both are formed was well oxidizing at a very low sedimentation rate we compiled seventeen published stratigraphic examples of phanerozoic oceanic red beds including the late cenozoic red clays in the pacific different hypotheses explain the origin of red pigmentation of limestones and shales including 1 detrital origin of iron derived from continental weathering 2 iron bacterial mediation at the time of sedimentation and 3 iron oxidation in oligotrophic highly oxic environment additional research on phanerozoic oceanic red beds is needed in order to better document their origin and palaeoceanographic and palaeoclimatic significance

new long term mass balance series for the swiss alps in this study we present 19 new or re analysed series of glacier wide seasonal mass balance for the swiss alps based on direct measurements the records partly start around 1920 and continue until today previously unpublished and unevaluated observations of point winter and annual balance are compiled from various sources and archives these highly valuable datasets have not yet been consistently evaluated and were thus unavailable to the scientific community using distributed modelling for spatial interpolation and extrapolation and homogenization of the point measurements we infer continuous series of area averaged mass balance the results are validated against independent decadal ice volume changes from photogrammetric surveys six of the new seasonal series cover 60 years and more and add a substantial amount of information on the variations of regional glacier mass change this will strengthen the worldwide collection of glacier monitoring data especially for the data sparse period before the 1980s we compare our results to existing long term series and present an updated assessment of mass balance variability and glacier sensitivity throughout the european alps

colour origin of upper cretaceous pelagic red sediments within the eastern pontides northeast turkey characteristic samples of upper cretaceous pelagic red sediments from different parts of the eastern pontides ne turkey have been investigated by x ray diffraction xrd x ray fluorescence xrf and scanning electron microscopy coupled with energy dispersive analyses sem edax the red sediments are composed of limestone and muddy limestone and characterized by abundant planktonic foraminifers hematite content ranges from 0 5 to 3 0 wt electron microscope observations suggest that the hematite pigment has a diagenetic origin the red colour is due to presence of hematite pigment and indicates oxidizing conditions during early diagenesis in a relatively deep marine environment

ice ablation as evidence of climate change in the alps over the 20th century 1 over fifty years of cumulative annual mass balance data for several glaciers in the alps shows similar fluctuations which seem to provide evidence of a common climatic signal separate winter and summer mass balance measurements from the claridenfirn glacier in switzerland since 1914 and the sarennes glacier france since 1949 show that 1 the annual mass balance is primarily driven by the summer mass balance term and 2 melting rate variations with time are very similar for these two glaciers located 290 km apart the increase in the ablation rate of 0 5 cm w e day 1 between the two periods 1954 1981 and 1982 2002 over these two glaciers corresponds to a 20 wm 2 rise in the energy flux at the glacier surface these results suggest that a common summer melting rate change may have affected the alps as a whole detailed observations on the sarennes glacier show that the origin of this strong increase in summer ablation since 1982 is not only a rise in the summer melting rate but also an increase in the ablation period during the months of september and october

quantifying the effects of climate and surface change on glacier mass balance when a mass balance is computed using an outdated map that computation does not reveal the actual mass change but older maps often must be used for practical reasons we present a method by which with a few additional measurements each year a mass balance computed with an outdated map can be transformed into an actual mass change this is done by taking into account the influence of changes in areal extent and changes in the surface elevation of the glacier since the map was made this method is applied to south cascade glacier washington u s a as an example the computed cumulative mass balance from 1970 to 1997 would have been 16 too negative if the 1970 map had not been updated while the actual volume change of a glacier is relevant to hydrological studies the change that would have occurred on a constant or static surface is more relevant to certain glacier dynamics problems and most climate problems we term this the reference surface balance and propose that such a balance which deliberately omits the influence of changes in area and surface elevation is better correlated to climatic variations than the conventional one which incorporates those influences

a stepwise screening system to select storm sensitive stalagmites taking a targeted approach to speleothem sampling methodology a stepwise stalagmite sample screening process was applied in order to select a stalagmite as a sensitive recorder of recent tropical cyclone rainfall events near belize field and laboratory criteria were combined in series to screen out candidate stalagmites whose characteristics indicated lower sensitivity to stormwater infiltration the approach described here was designed to increase the likelihood that selected stalagmites would increase the signal noise ratio of the target phenomenon in the resulting proxy records this four stage method for sample selection may be an important methodological consideration for researchers attempting to use speleothems for stable isotope paleotempestology hallmarks of this approach include 1 establishing a priori scientific targets 2 applying sample criteria in the form of contra indicators and 3 organizing the sample screening protocol into a series of practical stages the overall approach to stalagmite selection presented here supports cave conservation and can be adapted readily by others in support of different scientific goals it is hoped that other investigators will also publish field and laboratory sample selection schemes as increased transparency will provide new information invaluable to replication efforts and to advancing the field of speleothem paleo environmental studies

the importance of quaternary records in reducing risk from tropical cyclones numerous late holocene records of tropical cyclones have been collected from north east queensland australia they are in the form of multiple sedimentary ridges paralleling the shore the ridges are composed of coral fragments or shell and sand or pure sand a method to determine the intensity of the tropical cyclone responsible for deposition of the ridges at each site has been applied and the results suggest that in the majority of cases these features were deposited by very high magnitude events the results suggest that extrapolations of long term cyclone magnitude and frequencies from the 30 to 40 year long instrumental record which is the method commonly used to assess risk from this hazard substantially underestimate the risk from this hazard this is confirmed for the cairns region by an 800 year long high resolution isotope record of tropical cyclones preserved in a limestone stalagmite together the sedimentary and isotope records suggest that tropical cyclone activity in north east queensland has been in a phase of quiescence since before european settlement of the region in approximately ad 1870 it is suggested that the incorporation of the palaeo record into risk assessments will provide a more realistic guide to the magnitude frequency relationship of tropical cyclones and help reduce risk from this hazard as a consequence

too low δ18o of paleo meteoric low latitude water do paleo tropical cyclones explain it abstract isotopic analysis of rock samples showed anomalously 18 o depleted reconstructed isotopic composition of paleo meteoric water over southern israel between the late cretaceous and the early miocene with 18 o w as low as 14 smow this range is significantly lighter than the expected values for rain at the relevant paleo latitudes 8 n to 25 n it is similar or lighter than areas with meteoric water at the present climate in which rainfall contribution from tropical cyclone tc is significant rainfall from tcs is 18 o depleted because of the recirculation of the vapor into repeated precipitation or distillation cycles a paleo geographic reconstruction of the region shows that throughout the period there was a warm ocean to the east and southeast of the relevant area thus tcs formed over the ocean and made landfall on the coastline at a distance of 300 to 400 km to the east the reconstructed composition of the rainwater implies dominance of tcs at these times furthermore the combination of warmer seas and lighter rainwater than at present suggests that the tcs were more dominant than in the most tc prone coastal areas at the present climate the results of the present study suggest that climate during the relevant time periods was very different from the present with tc activity similar or exceeding the most tc prone locations in the world at the present climate this might also hint that warmer sea waters in the geological past were conducive to greater tc activity than in the present climate answering this question requires additional research

using remote sensing data to determine equilibrium line altitude and mass balance time series validation on three french glaciers 1994 2002 alpine glaciers are very sensitive to climate fluctuations and their mass balance can be used as an indicator of regional scale climate change here we present a method to calculate glacier mass balance using remote sensing data snowline measurements from remotely sensed images recorded at the end of the hydrological year provide an effective proxy of the equilibrium line mass balance can be deduced from the equilibrium line altitude ela variations three well documented glaciers in the french alps where the mass balance is measured at ground level with a stake network were selected to assess the accuracy of the method over the 1994 2002 period eight mass balance cycles results obtained by ground measurements and remote sensing are compared and show excellent correlation r 2 0 89 both for the ela and for the mass balance indicating that the remote sensing method can be applied to glaciers where no ground data exist on the scale of a mountain range or a given climatic area the main differences can be attributed to discrepancies between the dates of image acquisition and field measurements cloud cover and recent snowfalls constitute the main restrictions of the image based method

various types of olistostromes in a closing ocean basin tethyan himalaya cretaceous tibet abstract the cretaceous rocks of the central tethyan himalayas display different types of deep sea olistostromes and chaotic deposits which are accompanied by turbidites the deposits were incorporated into an accretionary prism and more or less deformed according to the composition and provenance of their clasts we distinguish four types of olistostromes 1 p type derived from the passive indian continental margin 2 po type derived from both the passive indian margin and ocean floor pelagic sediments and oceanic crust 3 poa type with clasts from the same sources as the po type but also containing material from the active margin along the lhasa block and 4 a and oa type mainly derived from the active margin accretionary prism and magmatic arc the occurrence of these different types of deep sea chaotic deposits in space and time is closely related to the evolution of the neo tethyan basin from a wide open ocean basin to a narrowing remnant and trench basin prior to collision whereas pure p type olistostromes formed when the basin was still wide predominating a type deposits characterize a late stage of basin evolution prior to collision mixed type olistostromes record an intermediate stage of basin evolution and require specific syn sedimentary tectonic activity

jurassic and cretaceous plate tectonic reconstructions abstract five plate tectonic reconstructions are presented illustrating the breakup of pangea and the evolution of the world s ocean basins during the early jurassic pliensbachian late jurassic volgian early cretaceous aptian late cretaceous cenomanian and latest cretaceous maestrichtian indicated on the maps are the location of the spreading centers intracontinental rifts subduction zones and transform faults which were active during each interval

photogrammetric reconstruction of glacier mass balance using a kinematic ice flow model a 20 year time series on grubengletscher swiss alps the kinematic boundary condition at the glacier surface can be used to provide glacier mass balance at individual points if changes in surface elevation horizontal and vertical surface velocities and surface slope are known vertical ice velocity can in turn be estimated from basal slope basal ice velocity and surface strain this relation is applied to reconstruct a 20 year mass balance curve of grubengletscher swiss alps largely using repeated aerial photogrammetry but only a minimum of field work for individual years the mass balance distribution on the glacier tongue was modelled with an accuracy of about 0 9 m a 1 ice mechanical assumptions and errors in glacier bed geometry markedly affect discrete mass balance patterns but are eliminated to a major extent when calculating year to year mass balance changes the resulting curve for the grubengletscher tongue 1973 1992 shows reasonable consistency with meteorological data and other glaciologically derived mass balance series large changes in measured ice speed on the glacier tongue 50 significantly governed the long term variability of ice thickness over the observational period

extracting the temporal signal from a winter and summer mass balance series application to a six decade record at glacier de sarennes french alps temporal trends related to recent climatic fluctuations are extracted from the longest glacier wide winter and summer mass balance series recorded in the alps at glacier de sarennes france for this all point balances measured at the glacier surface are used and different statistical models are developed and tested first lliboutry s linear variance analysis model is extended to the two seasonal components of the balance the explicit modelling of variability sources and correlations is proved useful for appropriately quantifying uncertainties in the different components of the balance and estimating missing data next a non exchangeable structure is added to model the winter and summer balance time series two change points separating different underlying trends are thus detected the first change was in 1976 with a shift of 23 in the winter balance the second was in 1982 for the summer balance series these systematic changes explain 20 30 of the variability of the different components of the balance the rest being made up of random interannual fluctuations simplified and or less physically based models are less efficient in capturing data variability as a result the cumulative glacier wide balance shows systematic parabolic trends which result in an accelerated mass loss for glacier de sarennes over the last 25 years

provenance analysis of upper cretaceous strata in the tethys himalaya southern tibet implications for timing of india asia collision abstract the provenance of upper cretaceous strata in the tethys himalaya provides critical constraints on the closure time of the neo tethys ocean and the initial india asia collision this paper reports detailed petrographic studies in situ detrital zircon u pb ages and lu hf isotopic analyses whole rock nd isotopes and cr spinel electronic microprobe data from upper cretaceous clastic sedimentary rocks of the tethys himalaya near gyangze southern tibet the berriasian coniacian jiabula formation consists of black mudstone chert and minor quartz arenite and is dominated by detrital zircons with archean cambrian u pb ages which were most likely derived from the indian continent overlying conformably is the santonian maastrichtian chuangde formation which consists of red shale limestone and chert the chuangde formation is in turn overlain by the late maastrichtian late paleocene zongzhuo formation which is composed of black mudstone and lithic sandstone enclosing various olistoliths of sandstone limestone and chert the rilang conglomerate is a lens which is located within the upper part of the zongzhuo formation and consists of an upward thinning and fining succession of volcanic conglomerate sandstone and black mudstone the zongzhuo formation and the rilang conglomerate record an abrupt influx of cretaceous zircon grains with juvenile hf isotopic compositions arc related cr spinels and positive end 0 sediments suggesting an arc and suture zone provenance the change in provenance of upper cretaceous strata from the southern indian continent to a northern arc and suture zone is attributed to either 1 initial collision between the indian plate and lhasa terrane or 2 initial collision between the indian plate and an intra oceanic arc we prefer option 1 that the initiation of india asia collision occurred during maastrichtian 70 65 ma

greater frequency variability of landfalling tropical cyclones at centennial compared to seasonal and decadal scales assessing risk from tropical cyclones and predicting the impact of this hazard under a human altered climate is based exclusively upon the behaviour of these events over the past 50 100 yr and often less critical to these determinations is an understanding of the full extent of the natural variability of this hazard the coarse resolution of millennial scale sedimentary records brevity of the instrumental register imprecision of longer historical accounts and lack of any long term high resolution records has led to the assumption that the total variability of tropical cyclone behaviour is encompassed within the seasonal to multi decadal oscillations observed to date we present a near 800 yr long annual resolution isotope record of tropical cyclones in northeast australia which displays marked centennial scale regimes our record demonstrates that the frequency variability of intense landfalling cyclones is greatest at centennial scale compared to seasonal and decadal oscillations switching between centennial scale regimes in this record occurred rapidly 10 20 yr highlighting the importance of accounting for this phenomenon in coastal planning and risk assessment our study highlights the importance of obtaining high resolution multi century records of tropical cyclone activity in order to more accurately assess future impacts of this hazard to human society

origin of the outburst flood from glacier de tete rousse in 1892 mont blanc area france extensive field measurements and historical data have been used to re analyse the cause of the outburst flood from glacier de tete rousse that devastated the village of saint gervais le fayet french alps in 1892 causing 175 fatalities the origin of this disaster was the rupture of an intraglacial cavity in glacier de tete rousse that released 200 000 m 3 of water and ice all previous studies have concluded that the intraglacial cavity was formed from a crevasse that was filled and enlarged by meltwater the re analysis presented here suggests that the reservoir of the upper cavity did not originate as an enlarging crevasse the origin of the meltwater reservoir was more likely a supraglacial lake formed before 1878 during a period of negative mass balance following a period of positive mass balance after 1878 the lake was hidden until the outburst flood of 1892 this means that such hazards may be detected by checking regularly for the formation of a lake on the surface of the glacier before it is hidden

statistical modelling of the surface mass balance variability of the morteratsch glacier switzerland strong control of early melting season meteorological conditions in this study we analyse a 15 year long time series of surface mass balance smb measurements performed between 2001 and 2016 in the ablation zone of the morteratsch glacier complex engadine switzerland for a better understanding of the smb variability and its causes multiple linear regressions analyses are performed with temperature and precipitation series from nearby meteorological stations up to 85 of the observed smb variance can be explained by the mean may june july temperature and the total precipitation from october to march a new method is presented where the contribution of each month s individual temperature and precipitation to the smb can be examined in a total sample of 2 24 16 8 million combinations more than 90 of the observed smb can be explained with particular combinations in which the may june july temperature is the most recurrent followed by october temperature the role of precipitation is less pronounced but autumn winter and spring precipitation are always more important than summer precipitation our results indicate that the length of the ice ablation season is of larger importance than its intensity to explain year to year variations the widely used june july august temperature index may not always be the best option to describe smb variability through statistical correlation

deep sea paleotemperature record of extreme warmth during the cretaceous oxygen isotope analyses of well preserved foraminifera from blake nose 30 n paleolatitude north atlantic and globally distributed deep sea sites provide a long term paleotemperature record for the late albian maastrichtian interval that is difficult to reconcile with the existence of significant cretaceous ice sheets given reasonable assumptions about the isotopic composition of cretaceous seawater our results suggest that middle bathyal water temperatures at blake nose increased from 12 c in the late albian through middle cenomanian to a maximum of 20 c during the latest cenomanian and earliest turonian bottom waters were again 12 c during the middle campanian and cooled to a minimum of 9 c during the maastrichtian correlative middle bathyal foraminifera from other ocean basins yield paleotemperature estimates that are very similar to those from blake nose comparison of global bottom water temperatures and latitudinal thermal gradients suggests that global climate changed from a warm greenhouse state during the late albian through late cenomanian to a hot greenhouse phase during the latest cenomanian through early campanian then to cool greenhouse conditions during the mid campanian through maastrichtian

seasonal mass balance gradients in norway previously discovered regularity in vertical profiles of net balance b n z on ten glaciers in norway also exists in profiles of both winter bw z and summer b s z seasonal balances all three profiles unlike those of many glaciers elsewhere in the world are remarkably linear variations of gradients db w dz and db s dz from year to year are small and correlate poorly with glacier total balances b w and b s glacier to glacier correlation is weak for both gradients but is strongly positive for b w and b s there are two direct consequences of these properties of the gradients that apply to both seasonal balances b w and b s first because db dz varies so little from year to year the difference in balance ab from year to year is nearly the same over the entire glacier except near the top and bottom of its altitude range therefore balance at a site near the middle of the altitude range of the glacier correlates very well with glacier total balance second this correlation combined with the strong positive correlation of balance from glacier to glacier is the reason balance at one altitude on one glacier correlates well with glacier total balance at other nearby glaciers

climatic and environmental controls on speleothem oxygen isotope values variations in speleothem oxygen isotope values d 18 o result from a complicated interplay of environmental controls and processes in the ocean atmosphere soil zone epikarst and cave system as such the controls on speleothem d 18 o values are extremely complex an understanding of the processes that control equilibrium and kinetic fractionation of oxygen isotopes in water and carbonate species is essential for the proper interpretation of speleothem d 18 o as paleoclimate and paleoenvironmental proxies and is best complemented by study of site specific cave processes such as infiltration flow routing drip seasonality and saturation state and cave microclimate among others this review is a process based summary of the multiple controls on d 18 o in the atmosphere soil epikarst and speleothem calcite illustrated with case studies primary controls of d 18 o in the atmosphere include temperature and relative humidity through their role in the multiple isotope effects variability and modifications of water d 18 o values in the soil and epikarst zones are dominated by evaporation mixing and infiltration of source waters the isotopically effective recharge into a cave system consists of those waters that participate in precipitation of caco3 resulting in calcite deposition rates which may be biased to time periods with optimal dripwater saturation state recent modeling experimental and observational data yield insight into the significance of kinetic fractionation between dissolved carbonate phases and solid caco3 and have implications for the hendy test to assist interpretation of speleothem d 18 o time series quantitative and semi quantitative d 18 o climate calibrations are discussed with an emphasis on some of the difficulties inherent in using modern spatial and temporal isotope gradients to interpret speleothems as paleoclimate proxy records finally several case studies of globally significant speleothem paleoclimate records are discussed that show the utility of d 18 o to reconstruct past climate

use of contrasting d h ratios of snows and groundwaters of eastern new york state in watershed evaluation the d h ratios of snow on the ground and groundwaters in eastern new york state in early spring differ by 50 notation this is large in comparison to the analytical precision of 1 and permits estimation of the input of snowmelt directly to runoff versus groundwater input to runoff resulting from increased hydraulic head as the snow melts and percolates into the ground in 1978 the high overflow resulting from snowmelt contained only 25 meltwater the rest was provided by an increased groundwater exfiltration

timing of diagenetic haematite growth in red pelagic limestones from gubbio italy abstract magnetite haematite and to a minor extent maghaemite are recognised in the cretaceous and paleocene red pelagic limestones at gubbio the magnetite is detrital or biological whereas the haematite grew during diagenesis from a goethitic precursor thermal and af demagnetization of samples collected from close to reversal boundaries indicate that the various magnetization components do not record the polarity reversal at exactly the same stratigraphic level in the few tens of centimetersbelow a recorded geomagnetic reversal defined by the magnetite magnetization some of the haematite grains are magnetized in the post reversal field the blocking temperature spectra of this haematite fraction with post reversal magnetization are found to shift toward higher temperatures as the reversal boundary is approached the blocking temperature spectra reflect the grain size spectra of the haematite which we interpret as arising by the continual nucleation of grains down to a certain burial depth where the conditions are no longer conducive to further haematite growth the depth below reversal boundaries to which haematite with post reversal magnetization can occur is estimated to be about 60 cm after compaction and is equivalent to a time of about 105 years for these particular sediments a detailed study of the magnetization components at reversal boundaries indicates that the first diagenetic growth of haematite through the single domain critical volume occurs prior to the mechanical fixation of the detrital or biological magnetite subsequently the diagenetic haematite grains do not rotate in response to the ambient geomagnetic field polarity as easily as the magnetite because of their occurrence as pigmentary coatings on larger non magnetic grains

mass balance gradients and climatic change it is generally assumed that the mass balance gradient on glaciers is more or less conserved under climatic change in studies of the dynamic response of glaciers to climatic change one of the following assumptions is normally made i the mass balance perturbation is independent of altitude or ii the mass balance profile does not change it simply shifts up and down observational evidence for such an approach is not convincing on some glaciers the inter annual changes in mass balance seem to be independent of altitude on others not at all moreover it is questionable whether inter annual variation can be projected on different climatic states to see what a physical approach might contribute we developed an altitude dependent mass balance model it is based on the energy balance of the ice snow surface where precipitation is included in a parameterized form and numerical integrations are done through an entire balance year with a 30 min time step atmospheric temperature snowfall and atmospheric transmissivity for solar radiation are all dependent on altitude so a mass balance profile can be calculated slope and exposure of the ice snow surface are taken into account and the effects of these parameters studied in general the calculations were done for 100 m elevation intervals climatological data from the sonnblick observatory austria 3106 m a s l and from vent 2000 m a s l oetztal alps austria served as input for a number of runs simulation of the mass balance profiles for hinterseisferner north easterly exposure and kesselwandferner southeasterly exposure yields reasonable results the larger balance gradient on kesselwandferner is produced by the model so exposure appears to be an important factor here sensitivity of mass balance profiles to shading effects different slope and exposure are systematically studied another section deals with the sensitivity to climatic change perturbations of air temperature cloudiness albedo and precipitation are imposed to see their effects on the mass balance profiles the results clearly show that in general mass balance perturbations depend strongly on altitude they generally increase down glacier and are not always symmetric about the reference state for typical climatic conditions in the alps we found that a 1 k temperature change leads to a change in equilibrium line altitude of 130 m three factors contribute to this large value turbulent heat flux longwave radiation from the atmosphere and fraction of precipitation falling as snow here the albedo feed back increases the sensitivity in a significant way

micro scale analysis of tree ring δ18o and δ13c on α cellulose spline reveals high resolution intra annual climate variability and tropical cyclone activity high resolution analysis of stable carbon and oxygen isotopic composition 13c and 18o of tree ring cellulose has been increasingly in demand for the study of climate seasonality droughts and tropical cyclone hurricane activity the peeling grinding method commonly used for tree ring cellulose preparation is both time consuming and labor intensive and often results in cross tracheid sampling that masks high frequency intra annual climate signals and short term climate events here we present a new method by extracting tree ring cellulose directly from wholewood spline that omits the peeling grinding step and allows for micro scale 13c and 18o analysis that facilitates high resolution seasonal climate study this ultrasound assisted non destructive extraction method has significantly increased the output of tree ring cellulose preparation while retaining the wood cell fabric wood cell wall fibers collected from the cellulose spline were directly loaded into pre weighed silver or tin capsules and packed after oven drying for stable oxygen or carbon isotope analysis a 3 045 mm annual ring subdivided over 26 sections for 13c and 18o analysis revealed remarkable intra annual isotopic variations 1 62 for 13c and 5 85 for 18o the intra annual 13c values inversely covary with the seasonal precipitation pattern suggesting moisture regulation on tree ring 13c variations the high resolution 18o analysis unravels tropical cyclone activities hurricanes frances and ivan in 2004 that are characterized by an abrupt decline in 18o values by 2 6 with a v shape pattern in tree ring latewood an algorithm is developed for establishing regional patterns of tree ring seasonal 13c and 18o for the study of the mean state of climate seasonality and its anomalies

air humidity and lake δ18o during the latest paleocene earliest eocene in france from recent and fossil fresh water and marine gastropod δ18o δ13c and 87sr 86sr detailed isotopic 18 o 13 c 87 sr 86 sr analyses have been performed on aragonitic fresh water brackish water and marine gastropod shells of latest paleocene earliest eocene age from northwestern europe fresh water shells e g viviparus lymnaea from sparnacian deposits in the paris basin show relatively high 18 o values in the range 4 to 0 1 large intrashell 18 o variability typically 3 is consistent with significant seasonal variation in precipitation and or temperature we also present intrashell isotopic profiles for 22 recent fresh water shells mainly viviparidae representing the major middle to low latitude climate zones e g sweden france portugal lake chad ceylon gambia congo lake victoria new guinea distinct isotopic patterns reflecting humidity and temperature characterize each of the climate zones comparing the results for recent and fossil shells suggests that the climate in northern france during sparnacian time was warm subtropical with a pronounced seasonal drought the 18 o composition of sparnacian lake water has been estimated from the fossil fresh water shell 18 o and by using seasonal temperatures derived from 18 o profiles of fully marine shells the best estimate of the 18 o composition of sparnacian lake water compared with eocene mean ocean water is 1 this is consistent with paleorain 18 o values of 3 to 5 similar to present mean rain 18 o standard mean ocean water values close to 4 in portugal at 40 n the paleolatitude of the paris basin during earliest eocene time the evaporated nature of sparnacian lake water contradicts hypotheses of globally equable humid conditions in the warm early eocene and instead suggests that dry subtropical highs occurred over the eastern parts of the oceans similar to today the results of this study demonstrate the potential of fossil fresh water carbonates to reconstruct the development of subtropical highs and hadley cell circulation in the past

best possible estimation of mass balance combining glaciological and geodetic methods variance analysis of the long time series of mass balances recorded on glacier de sarennes 45807 n 6807 e france since 1949 shows that the variability can be separated linearly in two spatial and temporal terms annual balances deviate from their mean values over the period of record by an annual amount that is uniform over the glacier annual balances at each stake are therefore highly correlated and sampling at a single site would be acceptable to record the annual deviation a result of the linear character of the variance is the possibility of obtaining a systematic error free estimate of the annual glacier total budget by combining the mean annual balance obtained from photogrammetry and the annual deviation obtained from the variance analysis rather than using the traditional area integration of balances at each stake

relative contribution of surface mass balance and ice flux changes to the accelerated thinning of the mer de glace alps over 1979 2008 by subtracting surface topographies from 1979 1994 2000 and 2008 we measured ice thinning rates increasing from 1 m a 1 1979 1994 to more than 4 m a 1 2000 2008 on the tongue of the mer de glace the relative contributions of changes in surface mass balance and ice fluxes to this acceleration in the thinning are estimated using field and remote sensing measurements between 1979 1994 and 2000 2008 surface mass balance diminished by 1 2 m w e a 1 mainly because of atmospheric warming mass balance changes induced by the growing debris covered area and the evolving glacier hypsometry compensated each other meanwhile the mer de glace slowed down and the ice fluxes through two cross sections at 2200 m a s l and 2050 m a s l decreased by 60 between 1979 1994 and 2000 2008 two thirds of the increase in the thinning rates was caused by reduced ice fluxes and one third by rising surface ablation however those numbers need to be interpreted cautiously given our inability to respect mass conservation below our upper cross section an important implication is that large errors would occur if one term of the continuity equation e g surface mass balance was deduced from the two others e g elevation and ice flux changes

20th century climate change inferred from four long term point observations of seasonal mass balance four long term time series of seasonal mass balance observations all starting in 1914 have been compiled for two stakes on claridenfirn and one stake on grosser aletschgletscher and silvrettagletscher switzerland these data represent the longest records of mass balance worldwide a mass balance model based on the temperature index approach is used to correct field data for varying observation dates and data gaps and to separate accumulation and ablation the homogenized continuous 93 year time series cover most of the 20th century and enable us to investigate temporal regional and altitudinal variability in mass balance and changes in the climatic forcing on glaciers a high altitude site shows summer balance trends opposite to those at three stakes located near the equilibrium line since 1975 melt rates have increased by 10 10 a 1 periods of enhanced climatic forcing are detected 1943 53 and 1987 2007 the energy consumed for melt was higher in the 1940s despite lower air temperatures compared to the years since 1987 we find evidence for a change in the glacier surface heat budget which has important implications for the long term stability of degree day factors in empirical temperature index modelling

stalagmite stable isotope record of recent tropical cyclone events we present a 23 yr stalagmite record 1977 2000 of oxygen isotope variation associated with 11 tropical cyclones tcs from actun tunichil muknal cave in central belize high resolution microsampling yielded a record of monthly to weekly temporal resolution that contains abrupt decreases negative excursions in calcite 18 o values that correspond with recent tc rain events nearby a logistic discriminant model reliably identifi ed tc proxy signals using the measurable parameters 18 o and 13 c values and single point changes in 18 o value the logistic model cor rectly identifi ed 80 of excursions as tc events and incorrectly classifi ed only 1 of nearly 1200 nonstorm sampling points in addition to enabling high resolution tc frequency reconstruction this geologic proxy also provides information about the intensity of individual tcs a multiple regression predicted tc intensity r 2 0 465 p 0 034 using sampling frequency and excursion amplitude consistent with previous low resolution studies we found that the decadal average 18 o value was lower during the 1990s when several tcs produced rainfall in the area but higher during the 1980s when only one tc struck longer accurately dated high resolution speleo them stable isotope records may be a useful new tool for paleotempestology to clarify associa tions between highly variable tc activity and the dynamic range of quaternary climate

altitude variation of glacier mass balance in scandinavia 1 for each of ten glaciers in norway and two in sweden vertical profiles of net balance bn z which are typically published as values at about a dozen altitudes are strongly linear and nearly parallel from year to year separate linear functions fit the bn z from year to year with r2 0 89 over the 12 glaciers a family of parallel lines for each glacier that differ from year to year only by an amount bn constant with altitude has r2 0 85 there is an altitude z on each glacier where the measured balance bn z correlates well with the glacier total bn with r 0 97 over the 12 glaciers a remarkable consequence of this and of the high correlation of bn between many of the glaciers in the region is that measurements on one glacier 1775 meters on hardangerjokulen provide a good estimate of bn at several other glaciers

mass balance of rhonegletscher during 1882 83 1986 87 les bilans de masse effectues sur le glacier des sources du rhone alpes suisses pendant differentes periodes 1884 85 1908 09 1979 80 et 1981 82 sont presentes

sensitivity of mass balance of five swiss glaciers to temperature changes assessed by tuning a degree day model a degree day model is used to assess the sensitivity of the mass balance of five swiss glaciers to temperature changes the model uses temperature data extrapolated from nearby climate stations and is tuned by varying precipitation to make the model fit the observed distribution of mass balance with altitude once the model is tuned the effect of temperature change is simulated by recalculating the mass balance with the same parameters as before but with a temperature increase of 1 c throughout the year the largest mass balance changes involving increased ablation of 1 m w e a 1 c 1 occur at the snout with a progressively smaller increase with altitude the area averaged sensitivities for the five glaciers are 0 7 to 0 9 m w e a 1 c 1 if annual precipitation also increased by 20 it would partly offset the effect of the 1 c higher temperatures but could not compensate for it