the paleoclimatic record provided by eolian deposition in the deep sea the geologic history of wind the mineral component of pelagic sediment is brought to the deep sea by transport in the wind extraction and analysis of this dust allows estimation of the past aridity of the eolian source region via flux determinations and of the intensity of the transporting winds from grain size data these two parameters the grain size and mass flux of dust vary independently there are three significant sources of modern dust eastern and central asia northwest africa and arabia all in the northern hemisphere as the rainfall associated with the intertropical convergence zone is an effective barrier to southerly transport of dust the northern hemisphere is an order of magnitude more dusty than is the southern an asymmetry that has characterized most of the cenozoic eolian flux data show that most of the northern hemisphere was more arid during glacial maxima with 3 to 5 times as much dust transported during glacial stages than during interglacials only northwestern south america varied in the opposite sense the periodicity of quaternary variation in both eolian flux and eolian grain size data is strongly influenced by the milankovitch cycles of orbital variability wind intensities vary on a shorter time scale than the general 100 kyr cycles of glaciation and general aridity eolian grain sizes display forcing at precessional 19 and 23 kyr tilt 41 kyr and at approximately 30 kyr periodicities as a result the generalization that winds are uniformly stronger during glacial times is not valid whole cenozoic records show that the largest change in dust flux an order of magnitude increase occurred in the northern hemisphere and reflects continental drying associated with the late pliocene onset of northern hemisphere glaciation southern hemisphere eolian records show no sign of paleoclimatic changes in the late pliocene the most important change in cenozoic atmospheric circulation was a severalfold reduction in wind intensity that occurred at the time of the paleocene eocene boundary before then latest cretaceous and paleocene winds were essentially as strong as those of the late cenozoic this shift appears to be one of several climatic responses to a change in the nature and amount of global heat transport at about 55 ma

fluctuations of eolian flux and ocean productivity in the mid latitude north pacific during the last 200 kyr abstract in order to understand fluctuations in terrestrial and marine environments a sedimentary core h3571 was investigated from the hess rise located in the mid latitude north pacific under the north westerly wind system the 18 o grain size and grain shape of type 1 quartz suggest that this quartz is of aerosol origin good correlation between al and aerosol quartz in content and mass accumulation rate mar indicates that the alumino silicate minerals in the sediments are mainly transported by wind mar of mineral aerosol maraerosol varies from 156 to 732 mg cm 2 kyr 1 during the last 200 kyr the maraerosol maxima occur in oxygen isotope stage ois 4 to latest ois 5 middle ois 6 moderate maxima occur in early ois 1 2 late ois 3 and middle ois 3 these maxima are ascribed to reduced precipitation during the summer monsoon and to strengthened wind speed during the winter monsoon the mean organic carbon total nitrogen atomic ratio is 7 2 suggesting that the organic matter in the core h3571 is also mainly of marine origin the mar of organic carbon marorganic exhibits two prominent maxima in ois 2 and 4 and relatively high values in middle and late ois 6 enhanced primary productivity is most likely to be responsible for the high burial rate of organic carbon in the sediments carbonate and phosphorus inputs with aerosol into sea surface have played a minor role through dissolution in diminishing pco2 in surface water during glacial times on the other hand the aerosol silica supply to the ocean may have some potential to affect the burial of biogenic silica into sediments the effect of mineral aerosol on the ocean carbon cycle would be greater in the coastal and hemipelagic regions of the western pacific and equatorial atlantic as compared with that in the hess rise regime

extending the vostok ice core record of palaeoclimate to the penultimate glacial period the ice core record of local temperature dust accumulation and air composition at vostok station antarctica now extends back to the penultimate glacial period 140 200 kyr ago and the end of the preceding interglacial this yields a new glaciological timescale for the whole record which is consistent with ocean records temperatures at vostok appear to have been more uniformly cold in the penultimate glacial period than in the most recent one concentrations of co2 and ch4 correlate well with temperature throughout the record

palaeoclimatological and chronological implications of the vostok core dust record the2 083 m vostok ice core recovered by the soviet antarctic expeditions has provided much information of climatic and environmental interest for a period covering a full glacial inter glacial cycle1 6 here we present and discuss the dust record obtained down to 2 202 m the final depth to which this core was extended in 1986 first we document the fact that major changes in aeolian deposits as recorded in the vostok core appear to be of global significance and confirm the existence of a link between high latitude aeolian deposits and the earth s orbital parameters7 8 second we propose atmospheric dust as a strati graphic marker to compare timing with other records of palaeocli mate and use the magnetic susceptibility profile measured along the rc11 120 indian ocean core9 for this purpose assuming that major dust events correspond to common aeolian inputs this approach indicates that the vostok and marine records were roughly in phase at the previous glacial interglacial transition

northern westerlies during the last glacial maximum results from cmip5 simulations abstractbased upon simulations from phase 5 of the coupled model intercomparison project cmip5 the vertical and regional characteristics of the northern westerlies during the last glacial maximum lgm are investigated in this study at the northern hemispheric scale all nine available models simulate a poleward shift of the 200 hpa jet and eight models simulate an equatorward shift of the 850 hpa jet compared to the preindustrial period these shifts are of approximately 2 3 latitude for the arithmetic multimodel mean the upper tropospheric cooling in the tropics possibly due to reduced latent heat release is expected to account for the poleward shift of the 200 hpa jet through the thermal wind relationship changes in the midlatitude baroclinic instability in response to the amplified polar cooling are associated with the jet stream in the lower troposphere through anomalous eddy activity in particular the types of predominant baroclinic eddies are regionally dependent the behavior of the 8

quaternary glacial history of the kanas valley chinese altai nw china constrained by electron spin resonance and optically stimulated luminescence datings abstract the chinese altai is located on the northern edge of central asia rich geological records of quaternary glaciations are preserved in this area however the glacial history in the chinese altai has hardly been investigated this study aims to rebuild the regional glacial history in the kanas valley of the chinese altai we present 14 electron spin resonance esr ages and 3 optically stimulated luminescence osl ages from glacial landforms by integrating with ages from previous studies five major glacial advances are identified during marine oxygen isotope stages mis 6 5 4 3 and 2 with ages of 167 0 16 0 123 0 18 0 ka 97 0 19 0 78 0 7 0 ka 76 0 16 0 73 1 6 6 ka 52 1 7 8 34 4 4 2 ka and 28 0 3 3 16 1 1 5 ka respectively the glacial advance during mis 5 is the local last glacial maximum and glaciers became successively more restricted from mis 5 to mis 2 in addition the extensive mis 3 glacial advance in the chinese altai contrasts with the absence of mis 3 glacial advance in the mongolia altai these glacial patterns reflect that precipitation brought by the westerlies might play a primary role on driving glacial advances during the last glacial in the chinese altai this glacial chronology is in reasonable agreement with existing glacial chronologies from other parts of the altai tian shan and pamir indicating similar climate controls on the patterns of quaternary glaciation across central asia highlands

late pleistocene continental climate and oceanic variability recorded in northwest pacific sediments core v21 146 provides a continuous record of northwest pacific pelagic sedimentation spanning the past 530 000 years downcore variations of 18o from benthic foraminiferal calcite were correlated to the specmap record to provide an age model for late pleistocene paleoclimatic and paleoceanographic variation fluxes of caco3 and eolian material have been determined by combining information about linear sedimentation rates bulk densities and component percentages the mass accumulation rate mar of caco3 varies from 58 to 1435 mg cm kyr 1 and exhibits the pacific ocean pattern of higher accumulation associated with glacial periods for the younger portion of the record however the pattern of caco3 accumulation appears to shift during the mid brunhes so that prior to 350 000 years ago it exhibits an opposite pattern of greater accumulation during interglacial periods the flux of eolian dust is a proxy measure of the source area aridity and correlates well to the loess soil stratigraphy in china dust fluxes range from 43 to 718 mg cm kyr 1 and are greater by a factor of about 4 during glacial times cross spectral analysis of the eolian flux and oxygen isotope records shows an inphase and coherent relationship at each of the major orbital periodicities of 100 41 and 19 kyr eolian grain sizes generally used as a proxy record of wind intensity range from 8 4 2 9 m to 6 2 13 6 m a change in grain size variability occurs near about 300 ka such that the older portion is characterized by lower frequency and higher amplitude fluctuations than the younger portion power spectra for the eolian grain size record show dominant peaks at 100 and 50 kyr and a broad 25 35 kyr peak but coherency to the oxygen isotope curve at only the 100 and 33 kyr periodicities the phase relationship for eccentricity between the eolian grain size and 18o records suggests that at the 100 kyr frequency the smallest grain sizes are associated with glacial conditions

aeolian dust dynamics in central asia during the pleistocene driven by the long term migration seasonality and permanency of the asiatic polar front loess paleosol sequences preserve detailed archives of climate change reflecting the dynamics of aeolian dust sedimentation and the paleodust content of the atmosphere the detailed investigation of particle size distributions psds of windblown sediments is an increasingly used approach to assess the paleorecord of aeolian dust dynamics the central asian loess belt offers the potential to reconstruct pleistocene atmospheric circulation patterns along an adjacent west east transect within interior eurasia through granulometric studies in this study we present the aeolian dust record of the loess sequence at remisowka se kazakhstan which reflects a detailed signal of glacial interglacial climate and atmospheric dynamics in central asia on the basis of radiocarbon and amino acid geochronologic data long term semicontinuous trends in the aeolian dust record of the last glacial cycle are observed and interpreted to reveal their paleoclimate signal in consideration of the modern synoptical atmospheric circulation patterns and aeolian dust transport in central asia it is likely that the observed trends reflect the long term migration seasonal duration and permanency of the polar front during the late pleistocene previously published models which focused on the reciprocal glacial interglacial influence of the zonal westerlies and the asiatic high on the aeolian dust transport in central asia were overly simplified and should be modified to include the major influence of the asiatic polar front as the polar front activity is intimately connected with the development and position of the interhemispherically active high level planetary frontal zone hpfz the presented data give insight to long term aeolian dust dynamics and climate variability of interior eurasia which are linked with interhemispheric climates

southern migration of westerlies in the northern hemisphere pep ii transect during the last glacial maximum abstract a southward shift of continuous and discontinuous permafrost zones and vegetation belts of taiga broad leaf deciduous and evergreen forests on the islands forming japan suggests a southern migration of the northern hemisphere nh summer westerly subtropical jet by around 3 5 of latitude at 135 140 e during the global last glacial maximum lgm since this jet induces the asian nh summer monsoon the southern shift caused a cooler and drier summer and the spread of deciduous forest in southern japan the expansion of mountain glaciers on the islands of japan also supports the southern migration of the subtropical westerly jet at present the ablation of snow occurs by heat and precipitation carried by the nh summer monsoon by comparison the position of the nh winter westerly subtropical jet remained unchanged presumably because its course was constrained by the himalayan tibetan plateau the northern limit of the kuroshio current corresponding to the boundary of the subtropical and subarctic water in the northwestern pacific ocean also migrated by around 3 during the global lgm the southern migration of the westerly subtropical jet suggests that the current situation where its location shifts during the nh summer to north of the tibetan plateau did not occur during the coldest phases of the global lgm although it did occur intermittently during marine isotope stage mis 3

aspects of atmospheric circulation the late pleistocene 0 950 000 yr record of eolian deposition in the pacific ocean rea d k 1990 aspects of atmospheric circulation the late pleistocene 0 950 000 yr record of eolian deposition in the pacific ocean palaeogeogr palaeoclimatol palaeoecok 78 217 227 the eolian component of pelagic sediments provides a proxy record of atmospheric circulation intensity and of dust transport examination of those records indicates that the atmosphere responds to orbital forcing but that during the past 875 000 years the variability in atmospheric circulation is at much shorter periods than the 100 000 year variation in ice volume the mid brunhes climatic event is well characterized in the eolian grain size records and in records of sea surface phenomena it is not seen in proxy indicators of either deep water or ice volume variability the increase in the amplitude of paleoclimatic variability that denotes the early late pleistocene transition occurs suddenly about 875 000 years ago in the eolian grain size record which is about 20 000 to 25 000 years earlier than the transition in the deep sea caco3 dissolution record or in the 8180 proxy record of ice volume

postglacial environmental change of the pacific ocean off the coasts of central japan abstract downcore changes in microfossil assemblages and oxygen isotope ratios in three piston cores recovered from the northwestern pacific off central japan show that the subtropical kuroshio front was located to the south of c 4 core site lat 33 n during the last glacial the front then advanced northward passing over the c 4 site and the c 6 site 34 6 n at about 13 ka and 10 ka respectively and reached the c 1 core site 36 n at about 7 ka after 5 5 ka it retreated to the area between the c 1 and c 6 sites a brief but significant cold event the readvance of the cold oyashio current is recognized between 11 and 10 ka in the two northern cores but the current did not reach the southern c 4 site a contemporaneous cold event is known in the north atlantic and the cooling was probably a global phenomenon likely to be associated with lowering of sea level contamination of isotopically light water is apparent between 14 and 11 ka in the marked change in isotopic composition of benthic foraminifers oxygen isotope ratios of planktonic foraminifers show that prior to the advance of the kuroshio front the surface water at these core sites was isotopically lighter than the kuroshio water at that time

sinking of concrete modules into a sandy seabed a case study abstract three submerged coastal structures on the sandy seabed at santa maria del mar smm beach in southwest spain were monitored during the six months after installation starting in november of 2005 the monitoring evaluated the self burial phenomenon of the 40 precast modular concrete elements of the three structures assessment included scouring around the structures their vertical movement the sinking velocity of the modules and the resulting beach profiles pressure sensors and precision topographies permitted continuous monitoring of the self burial process for the first time in a full scale case comparison of two bathymetries one performed immediately prior to installation and another performed six months after installation indicated slight accretion of the seabed whereas intermediate topographic surveys indicated extensive scouring around the structures the three structures began sinking into the sandy bottom platform immediately after placement and continued until they reached the rocky bottom this study implemented a new methodology using pressure sensors attached to the concrete modules to monitor the structural sinking unexpectedly the average sinking speed was extremely rapid at approximately 3 6 cm day 50 of the height of the element was reached in three to six weeks the results of this study are also compared with the results of other full scale cases among other conclusions data from this study indicated that the sinking rate of the modules in smm beach was one order of magnitude greater than the other values

surface water temperature changes in the high latitudes of the southern hemisphere over the last glacial interglacial cycle a set of numerical equations is developed to estimate past sea surface temperatures sst from fossil antarctic diatoms these equations take into account both the biogeographic distribution and experimentally derived silica dissolution the data represent a revision and expansion of a floral data base used previously and includes samples resulting from progressive opal dissolution experiments factor analysis of 166 samples 124 holocene core top and 42 artificial samples resolved four factors three of these factors depend on the water mass distribution one subantarctic and two antarctic assemblages factor 4 corresponds to a dissolution assemblage inclusion of this factor in the data analysis minimizes the effect of opal dissolution on the assemblages and gives accurate estimates of sst over a wide range of biosiliceous dissolution a transfer function dtf 166 34 4 is derived from the distribution of these factors versus summer sst its standard error is 1 c in the 1 to 10 c summer temperature range this transfer function is used to estimate sst changes in two southern ocean cores 43 s and 55 s which cover the last climatic cycle the time scale is derived from the changes in foraminiferal oxygen and carbon isotopic ratios the reconstructed sst records present strong analogies with the air temperature record over antarctica at the vostok site derived from changes in the isotopic ratio of the ice this similarity may be used to compare the oceanic isotope stratigraphy and the vostok time scale derived from ice flow model the oceanic time scale if taken at face value would indicate that large changes in ice accumulation rates occurred between warm and cold periods

snowline elevation and eolian dust flux in the japanese islands during isotope stages 2 and 4 abstract changes in snowline elevation and dust flux clearly contrast the paleoenvironments of the japanese islands during isotope stages 2 and 4 a lower snowline elevation and a smaller dust flux during isotope stage 4 suggests a climate with a cold and dry summer dominated by winter monsoonal precipitation between 70 and 55 ka a higher snowline elevation and a larger dust flux during isotope stage 2 indicates a climate with a cold and very dry summer with a minimized winter monsoon precipitation especially around 18 ka a drier climate during stage 2 can be explained by 1 a lowering of sea surface temperature in the japan sea by blocking the warm tsushima current during a sea level lowering 2 the extension of sea ice over the northern part of the japan sea and the sea of okhotsk and 3 weakening of the summer monsoon and the southern migration of the polar front the increase in dust flux in both stages 2 and 4 suggests an intensification of westerlies and winter monsoon during these stages a bigger dust flux in stage 2 than stage 4 reflects 1 stronger westerlies and winter monsoon and 2 the emergence of continental shelf which became an important dust source

eolian deposits of the northern margin of the south china jianghan basin reconstruction of the late cretaceous east asian landscape in central china abstract the late cretaceous honghuatao formation includes a succession of thick clastic sedimentary sequences which are widely exposed in northwestern jianghan basin central china here detailed sedimentological and facies architectural analyses are performed allowing to re interpret and identify the controversy for sedimentary environment and to investigate the paleoclimatic condition the honghuatao stratigraphic sequence includes eolian dunes and dry interdunes deposits with fluvial channel deposits at the bottom and top the vertical change between fluvial and eolian systems indicates alternating wet and dry climate at the same time the provenance analysis combined with the paleocurrents from the w nw and ne indicates that huangling dome south qinling belt and dabie orogen supply the main detrital source for the honghuatao formation the late cretaceous first rifting subsidence in the jianghan basin provided accommodation space for the preservation of the aeolian accumulation moreover the existence of the mountain belts around the basin that is the orographic effect precluded the winds from transporting humidity to the interior of the jianghan basin generating the desert system this study shows that the formation of eolian deposits in the honghuatao formation and coeval strata in numerous adjacent basins was a sedimentary response to the prevailing desert climate in the mid to low latitude areas of the northern hemisphere during the late cretaceous which was predominately controlled by the subtropical high pressure system on a planetary scale

coherent response of arabian sea upwelling and pollen transport to late quaternary monsoonal winds the indian summer monsoon causes large seasonal changes in the environments of both eastern africa and the arabian sea here we compare time series 140 kyr long of selected pollen types and foraminiferal upwelling faunas preserved in marine sediments to identify the frequencies of their variability and the coherence and phase of the terrestrial and marine responses to monsoonal circulation during interglacial intervals the pollen and upwelling records of the western arabian sea indicate stronger monsoons and are both coherent and in phase at periodicities near the precession of the earth s rotational axis 23 kyr we conclude that the strength of the monsoonal southwesterlies accounts for this high coherence of marine and terrestrial records during interglacial intervals low correlation during glacial phases indicates weaker monsoons and some decoupling of these two records these data indicate that two distinct modes of monsoon variability may exist an interglacial mode with strong monsoons and effective coupling of terrestrial and marine records and a glacial mode with both weaker monsoons and decreased linkage between arabian sea pollen and upwelling records

photosynthetic fractionation of 13c and concentrations of dissolved co2 in the central equatorial pacific during the last 255 000 years carbon isotopically based estimates of co2 levels have been generated from a record of the photosynthetic fractionation of 13c is equivalent to epsilon p in a central equatorial pacific sediment core that spans the last approximately 255 ka contents of 13c in phytoplanktonic biomass were determined by analysis of c37 alkadienones these compounds are exclusive products of prymnesiophyte algae which at present grow most abundantly at depths of 70 90 m in the central equatorial pacific a record of the isotopic composition of dissolved co2 was constructed from isotopic analyses of the planktonic foraminifera neogloboquadrina dutertrei which calcifies at 70 90 m in the same region values of epsilon p derived by comparison of the organic and inorganic delta values were transformed to yield concentrations of dissolved co2 is equivalent to c e based on a new site specific calibration of the relationship between epsilon p and c e the calibration was based on reassessment of existing epsilon p versus c e data which support a physiologically based model in which epsilon p is inversely related to c e values of pco2 the partial pressure of co2 that would be in equilibrium with the estimated concentrations of dissolved co2 were calculated using henry s law and the temperature determined from the alkenone unsaturation index u k 37 uncertainties in these values arise mainly from uncertainties about the appropriateness particularly over time of the site specific relationship between epsilon p and 1 c e these are discussed in detail and it is concluded that the observed record of epsilon p most probably reflects significant variations in delta pco2 the ocean atmosphere disequilibrium which appears to have ranged from approximately 110 microatmospheres during glacial intervals ocean atmosphere to approximately 60 microatmospheres during interglacials fluxes of co2 to the atmosphere would thus have been significantly larger during glacial intervals if this were characteristic of large areas of the equatorial pacific then greater glacial sinks for the equatorially evaded co2 must have existed elsewhere statistical analysis of air sea pco2 differences and other parameters revealed significant p 0 01 inverse correlations of delta pco2 with sea surface temperature and with the mass accumulation rate of opal the former suggests response to the strength of upwelling the latter may indicate either drawdown of co2 by siliceous phytoplankton or variation of co2 si oh 4 ratios in upwelling waters

glacial and interglacial eolian dust dispersal patterns across the chinese loess plateau inferred from decomposed loess grain size records previous studies have indicated that a genetically meaningful decomposition unmixing of loess grain size distributions can be accomplished with the end member modeling algorithm emma the independent decomposition of two series of loess grain size records from the ne tibetan plateau and loess plateau spanning the last glacial interglacial cycle indicates that the two data sets are described by very similar mixing models the average mixing model presented here is regarded as representative for the vast loess region in northern china and allows quantification of the contribution of three loess components to the loess grain size distributions a genetic interpretation and the paleoclimatic significance of the average mixing model have been provided by comparison of the modeled loess components with modern dust samples in terms of their grain size distribution and flux rates and by the distribution patterns of the loess components across the loess plateau reconstructed for the last two glacial interglacial cycles the sandy and silty loess components represent the coarse dust fraction supplied by saltation and short term suspension processes over the proximal part of the loess plateau during major dust outbreaks in spring and early summer the low level winter monsoon northwesterly wind system is the likely transporting agent for these dust events a clayey loess component represents the fine dust component supplied over the entire loess plateau by long term suspension processes during major dust outbreaks and as part of a background supply system the clayey loess component in the glacial loess deposits is dominantly supplied during major dust outbreaks by the northwesterly winter monsoon whereas the clayey loess component in the interglacial paleosols is mainly supplied by non dust storm processes possibly with a significant contribution by the high level subtropical jet stream westerly winds

mid pliocene warmth stronger greenhouse and stronger conveyor abstract three million years ago prior to the onset of northern hemisphere glaciation global mean temperatures may have been as much as 3 5 c warmer than at present we present evidence based on the carbon isotopic composition of marine organic matter that atmospheric co2 levels at this time were on average only about 35 higher than the preindustrial value of 280 ppm we also present carbon isotopic evidence for stronger thermohaline circulation in the atlantic ocean during the warmest intervals and propose that the north atlantic conveyor belt may act as a positive feedback to global warming by enhancing sea ice retreat and decreasing high latitude albedo based on our results it seems unlikely that the mid pliocene warm period was a doubled co2 world

late pleistocene glacial advances in the western tibet interior it has long been observed that the timing of glacial advances is asynchronous across the himalaya karakoram tibet plateau hktp but the climatic implications if any remain unclear resolving this question requires additional glacial chronologies from unique spatial and climatic regimes as well as an analysis of how glaciers within different regimes are likely to have responded to past climate changes this study presents a 10be 21ne chronology from the mawang kangri range of western tibet 34 n 80 e an arid high elevation site we identify advances at 123 83 and 56 kyr which agree reasonably well with sites in the immediate vicinity but are asynchronous relative to sites across the entire hktp and relative to sites in the western hktp to evaluate hktp wide asynchroneity we compile dated glacial chronologies and classify them by the approximate timing of their maximum recent advance this result shows a strong spatial clustering of young mis 1 2 relative to older mis 3 5 maximum advances further comparison with modern precipitation temperature and topographic data show that the pattern of hktp wide asynchroneity is broadly independent of topography and can potentially be explained by local responses to changes in temperature at either very warm wet or cold dry sites sites that receive intermediate amounts of precipitation are more ambiguous although spatial clustering of mis 1 2 vs mis 3 5 advances is suggestive of past variations in precipitation at these sites in western tibet no spatial or climatic correlation is observed with the timing of maximum glacial advances we suggest this could arise from mis interpretation of disparate boulder ages generated by a prolonged mis 3 4 glacial advance in the western hktp

organic carbon paleo pco2 and marine ice core correlations and chronology here we present evidence that marine organic matter 13 c measurements can closely reproduce the vostok ice core co 2 record and in addition can be used to evaluate the absolute vostok chronology and the transfer of that chronology between the marine and terrestrial realm our data supports recent speculations that the base of the vostok ice core 2755 m is still within oxygen isotope stage 7 in agreement with recent orbitallytuned ice core chronologies

timings and causes of glacial advances across the pep ii transect east asia to antarctica during the last glaciation cycle a comparison of glacial advances through the last glacial cycle between northern and southern hemispheres in the pep 2 transect east asia and australasia revealed 1 a relatively good synchrony of glacial advances during the lgm across the whole transect except antarctica 2 a rough synchrony in glacial advances in the karakorums himalayas japan and new zealand during marine isotope stages mis 3 and 4 although the age control is still poor and 1 a greater glacial extent in mis 3 and 4 than in mis 2 the lgm advances are driven by northern hemisphere temperature forcing but the mis 3 and or mis 4 advances appear to be dominantly controlled by the effects of moisture availability or lack of thereof in mainland australia and antarctica glaciers advanced only in the most humid phases in himalaya and karakorum where the moisture is supplied both by a summer monsoon and the westerlies timings of glacier advance coincide with both summer monsoon enhancement and westerly intensification in japan the glacier extent is controlled by monsoon changes sea surface temperatures ssts in the japan sea moisture source and by zonal shifts in westerly circulation in new zealand either insolalion changes or changes in the intensity of westerly circulation are invoked lis the main track of the westerlies did not change greatly during glacial times c 2003 elsevier ltd and inqua all rights reserved

the dust provenance and transport mechanism for the chengdu clay in the sichuan basin china the chengdu clay in the sichuan basin china was named by thorp and dye in 1936 the genesis dust provenance and transport mechanism for the chengdu clay however are still debated in the present work the chengdu clay and adjacent loess from the eastern tibetan plateau the chinese loess plateau and the qinling mountains were investigated the content and grain size distribution of quartz quartz 18o sm nd isotopic system rare earth elements and other trace element concentrations for the chengdu clay and its adjacent loess were analyzed based on comparison and spatial variation analysis the results confirm that the chengdu clay is of aeolian origin the dust provenance of the chengdu clay differs from those of the adjacent loess the chengdu clay is possibly of local origin and is transported by an ancient katabatic wind over a short distance during glacial and stadial periods the alluvial sediments in the northwestern sichuan basin are possibly the major sources of the chengdu clay there is little possibility of an effective aeolian transport bringing dust from the tibetan plateau the arid area in northwestern china or inner mongolia into the sichuan basin where it may be deposited to form the chengdu clay thus long range dust transport by the east asian winter monsoon the westerly jet or the tibetan plateau winter monsoon possibly plays a minor role in controlling the magnitude of the dust flux of the chengdu clay in the sichuan basin

mountain glaciation in japan and taiwan at the global last glacial maximum abstract montane glaciation in japan and taiwan was maximal in mis 3 4 and glacier extent at the global last glacial maximum lgm was much more limited data from four areas in japan and two in taiwan where the topographical and chronological positions of the terminal moraines are well determined and the chronology is controlled by radiocarbon ams and 10be cosmogenic dates are presented in this paper equilibrium line altitudes elas at global lgm are around 1500 m in the hidaka range hokkaido 2500 m in the northern japanese alps 2700 m in the central japanese alps 2800 m in the southern japanese alps in japan and 3300 m in northern taiwan and 3500 m in central taiwan the elas are mostly determined by maximum discharge accumulation ablation area ratio aar and glacier toe and headwall ratio thar methods the pattern of contours of elas indicates a strong influence of precipitation control on glacier development in this region the ela depression at global lgm in japan was 1100 1300 m except in the northernmost part of the northern japanese alps only 400 m where the present hypothetical ela is extraordinarily low because of abundant snowfall the ela depression at global lgm in taiwan is estimated at about 1100 1300 m without consideration of uplift

carbon isotope records from pacific surface waters and atmospheric carbon dioxide we have stacked planktonic carbon isotope data from three cores in the western equatorial pacific in order to generate a new reconstruction of atmospheric carbon dioxide over the past 450 000 years our new reconstruction resembles that of shackleton et al 1983 based on data from east pacific core v19 30 which successfully predicted features that were subsequently verified by barnola et al 1987 in the record from the vostock ice core in addition the new data confirm the discovery of shackleton and pisias 1985 that changes in atmospheric co2 lead changes in ice volume and hence probably contributed to the glacial interglacial cycles our new reconstruction avoids some of the deficiencies of the previous reconstruction in particular the planktonic species neogloboquadrina dutertrei on which the earlier reconstruction depends does not calcify in truly nutrient free surface water as the model assumes whereas our new reconstruction uses globigerinoides sacculifer which is expected to be more reliable in addition the surface waters in the west pacific are closer to the nutrient free ideal on which the model broecker 1982 depends on the other hand the amplitude of the new reconstruction is significantly smaller than the amplitude observed by barnola et al 1987 it is not clear whether this smaller range is a better estimate of the amplitude of the biological pump effect or whether the true amplitude is reduced by bioturbation in the west pacific cores that we studied

does sedimentary organic δ13c record variations in quaternary ocean co2 aq ocean surface water co2 aq variations based on glacial interglacial changes in sediment delta 13corg are shown to compare favorably with reconstructions based on ice core co2 in particular an approximate 80 microatmospheres increase in atmospheric pco2 during the last glacial interglacial transition is calculated to correspond to a 3 4 micromolar increase in ocean surface water co2 aq at atmospheric equilibrium a widespread marine delta 13corg decrease of 1 2 accompanied this event and was not preceded by an equivalent isotopic change in surface water total dissolved inorganic carbon these observations support the hypothesis that co2 aq influences photosynthetic isotope fractionation between marine inorganic and organic carbon pools and therefore that plankton sediment delta 13corg may serve as a proxy for surface water co2 aq

holocene treeline shifts and monsoon variability in the hengduan mountains southeastern tibetan plateau implications from palynological investigations abstract the upper 8 45 m of a sediment core from lake naleng were analysed for its pollen and charcoal content to detect vegetation climate and human activity changes on the southeastern tibetan plateau tp since the pleistocene holocene transition 11 7 cal kyr bp the application of pollen indicator taxa pollen sums biomisation and multivariate analysis helped to reconstruct environmental conditions during the holocene furthermore 64 surface samples from the southeastern tp and its foreland were analysed to investigate the relationship between modern pollen assemblages and vegetation the modern vegetation was recorded in the surface pollen assemblages by pollen indicator types although sediments also contain pollen spectra extra regional pollen transported from lower vegetation belts which is seen as a consequence of steep elevation gradients at the southeastern margin of the tp the relation between different vegetation belts and temperature from the modern sample sites was used to infer quantitative temperature trends for the holocene record spreading of forests at the beginning of the holocene marks the transition to warmer conditions from 10 7 to 4 4 cal kyr bp open abies betula forests were found at lake naleng probably reflecting a stronger than present summer monsoon temperature range reconstructions suggest a temperature that was about 2 3 c warmer and a treeline position that was 400 600 m higher than today a severe climate deterioration with temperatures about 1 2 c colder than before is documented by a retreating forest between 8 1 and 7 2 cal kyr bp forests retreated while subalpine rhododendron shrubs spread around lake naleng indicating colder conditions with temperatures 1 2 c below early and mid holocene level after 4 4 cal kyr bp the forest decline at 4 4 cal kyr bp is considered to reflect climatic conditions as low concentrations of charcoal particles found in this period exclude human induced fires as reason for the forest retreat however grazing indicators imply human influence on the environment since 3 4 cal kyr bp around lake naleng we therefore consider the rapid treeline shift seen at 3 4 cal kyr bp as partly generated by human activity and partly by climatic conditions

asian summer monsoon instability during the past 60 000 years magnetic susceptibility and pedogenic evidence from the western chinese loess plateau abstract the 28 m high resolution shajinping loess section in lanzhou on the western chinese loess plateau records a 60 ka millennial summer monsoon variation the record shows that asian summer monsoons have rapid episodic pulse enhancements spanning only ca 1 2 ka in high frequency domain and having sub milankovitch cycles of progressive weakening in low frequency domain in the last glaciation soil formation seems to occur with a surprisingly fast response to these summer monsoon enhancements resulting in weakly or moderately developed paleosol sequences both the pattern and timing of the summer monsoon enhancements show that they can be correlated to most major warm dansgaard oeschger episodes and long term cooling bond cycles of the north atlantic climatic records indicating a possible teleconnection between tropic oceanic air masses and the north atlantic climatic system but differences exist for the transition of mis 2 3 and the holocene where extraordinarily heavy dust input events and fairly variable climatic fluctuations occur for the former and latter respectively a westerlies swing model is proposed to interpret this link

land ocean linkages over orbital and millennial timescales recorded in late quaternary sediments of the japan sea late quaternary sediments of the japan sea are characterized by centimeter to meter scale alternations of dark and light layers which are synchronous basinwide high resolution analyses of the sediments from ocean drilling program site 797 reveal that deposition of the meter scale alternations reflect variations in paleoceanographic conditions which were closely associated with glacio eustatic sea level changes through the modulation of the volume and character of the influx to the sea through the tsushima strait the centimeter to decimeter scale alternations reflect millennial scale variations which are possibly associated with dansgaard oeschger d o cycles with each dark layer appearing to correspond to an interstadial this variability is attributed to the development of a humid climate in central to eastern asia and the consequent increase in discharge from the huanghe and changjiang rivers during interstadials this caused expansion of the east china sea coastal water ecscw which penetrated more strongly into the japan sea the increased influence of the lower salinity nutrient enriched ecscw reduced deep water ventilation and enhanced the surface productivity leading to the development of anoxic bottom waters and deposition of the dark layers thus the centimeter to decimeter scale alternations of the dark and light layers record wet and dry cycles in central to eastern asia possibly associated with d o cycles

grain size distribution and depositional processes of the mineral component of abyssal sediments lessons from the north pacific grain size analyses of the mineral component of abyssal pacific surface sediments show two distinctly different size distributions that can be associated with sediments that are dominantly eolian and dominantly hemipelagic respectively in the range of 1 to 30 m eolian grains show a distinct size mode at about 2 m 9 and little material coarser than about 16 m 6 hemipelagic grains are characterized by a much flatter size distribution that has a broad size mode near 2 m 9 and important amounts of material coarser than 16 m 6 this ability to distinguish between hemipelagic and eolian grains will obviate some long standing concerns in the interpretation of deep sea sediments examples of the utility of this technique are given for the north pacific and south atlantic

real time infrasonic monitoring of the eruption at a remote island volcano using seismoacoustic cross correlation s u m m a r y on 2013 november 20 a submarine eruption started close to nishinoshima island which lies 1000 km south of tokyo real time monitoring of the eruption is crucial for understanding the formation processes of the new volcano island and related disaster prevention in situ monitoring however is difficult in practice because the closest inhabited island chichijima is 130 km away from nishinoshima this study presents an infrasonic monitoring method that uses cross correlating records at a pair of online stations on chichijima one is the horizontal ground velocity recorded at a permanent seismic station operated by the japan meteorological agency jma the seismic records were corrected for atmospheric pressure using an empirical ground response to infrasound the other is the air pressure recorded at the jma meteorological observatory for each station we divided the whole records into 3600 s segments to suppress outliers each segment was normalized by the envelope function we then calculated cross correlation functions between the pair of stations using the fast fourier transform they present clear successive arrivals of infrasound coming from nishinoshima we also conducted an offline tripartite array observation using three low frequency microphones with a station spacing of 50 m installed in 2013 may the array analysis supports the results obtained from the online stations the typical root mean squared amplitude is on the order of 0 01 pa and the typical duration is several days the amplitudes were primarily controlled by the effective sound velocity structure from nishinoshima to chichijima the infrasonic observations together with the meteorological observation at chichijima suggest that infrasonic activity was not present in the first two weeks in 2015 january with the help of a more quantitative estimation of the meteorological effect we could infer eruptive activity in real time now many online seismic stations are available worldwide this study shows that installation of another infrasonic sensor close to the existing seismic station 1 km is useful for monitoring a remote island volcano in real time

glacial interglacial changes in the east australian current the east australian current eac is the western boundary current of the south pacific gyre transporting warm tropical waters to higher southern latitudes recent modelling shows that the partial separation of the eac 32 s and the coupled formation of the tasman front 34 s are caused by a steep gradient in the zonally integrated wind stress curl analysis of oxygen isotope ratios 18o in the planktonic foraminifer globigerinoides ruber from sediment cores from the coral sea and tasman sea indicates that the eac separation shifted northward to between 23 and 26 s during the last glacial we suggest these results indicate a significant change in the pacific wind stress curl during the glacial given recent evidence for el nino like conditions in the pacific during the last glacial with a reduction in the east west sea surface temperature sst gradient we suggest that weaker trade winds combined with more northerly stronger westerlies were associated with a change to the wind stress curl which repositioned the eac separation and tasman front in contrast by 11 ka bp the eac separation was forced south of 26 s this southward shift was synchronous with a rapid warming of tropical ssts and the onset of a la nina like sst configuration across the tropical pacific it appears that the south pacific trade winds strengthened accordingly causing the eac to readjust its flow this readjustment of the eac marks the onset of modern surface ocean circulation in the southwest pacific but the present eac transport was only achieved in the late holocene after 5 ka bp

small latitudinal shift in the kuroshio extension central pacific during glacial times evidence from pollen transport the mid latitude area of the central pacific is sensitive to ocean environmental change because latitudinal fluctuation in a transition zone between subtropical and subarctic waters has played an important role in climatic change in east asia the north pacific and north america higher amounts of pollen and spores were found in core h3571 on the hess rise during the glacials than during the interglacials pollen originating from broadleaf deciduous forest in warm and humid environments as well as from boreal conifers and tundra park tundra in cold and wet environments occurred during the glacials the boreal conifer pollen such as tsuga picea and haploxylon could originate from the central japanese archipelago that ephedra was supplied from the asian continent and that the main source regions for the rest of the pollen and spores were from the southern japanese archipelago to the area around the east china sea therefore ocean current transportation was important for the transportation of pollen and spores to the hess rise this evidence demonstrates a small southward shift in the kuroshio extension during the glacials it also suggests that terrestrial organic matter om deposited in the open sea may also be transported by ocean currents reflecting coastal terrestrial environments although it is widely believed that terrestrial om in open sea sediments is of aerosol origin

correlation between climate events in the north atlantic and china during the last glaciation episodes of massive iceberg release heinrich events 1 3 into the north atlantic ocean during the last glaciation were associated with recurring episodes of unusually cold north atlantic surface water bond cycles 4 and cold air temperatures over greenland dansgaard oeschger events 5 6 four of the youngest of these cold events have also been reported in climate records from sites outside the north atlantic region7 but until now the entire suite has been identified only in north atlantic marine sediments greenland ice core records and tentatively in french lake sediments8 here we examine grain size data from chinese loess and intercalated accretionary palaeosols of last glacial age for evidence of similar climate signals remote from the north atlantic region we see grain size maxima with ages that match those of the last six heinrich events which we interpret as an indication of the changing strength of the east asian winter monsoon which largely controls the transport and deposition of central asian aeolian dust thus it seems that these heinrich events have left their signature in the chinese loess record this is consistent with simulations of the glacial climate9 which imply that the climates of the north atlantic and china were linked by the effect of westerly winds