human resilience to lateglacial climate and environmental change in the scheldt basin nw belgium recent palaeoenvironmental analyses in the scheldt basin in nw belgium have identified significant hydrological and vegetation changes between greenland interstadial 1b gi 1b and greenland stadial 1 gs 1 younger dryas yd that enable us to develop hypotheses to explain the radical changes in land use and lithic technology observed between the federmesser and post federmesser occupation of the region the highly productive lacustrine environments of the lower scheldt basin during the allerod enabled relatively high population packing by federmesser groups exploiting the region within a residential mobility system federmesser assemblages indicate a flexible lithic technology centered on the production of unstandardized blades and flakes that were intensively backed to shape various tool forms the destabilization of these landscapes in the scheldt basin between gi 1b and gs 1 yd and the ensuing cold of the yd changed the composition of important secondary biomass from less mobile ungulate species to seasonally mobile reindeer populations human populations were resilient to these changes by developing a highly standardized micro blade technology and microlithic toolkit

plio pleistocene megacycles record of climate and tectonics abstract paleoclimatic records from the deep sea floor show that in the last 3 m y more than 100 oscillations of mild and cool global climate took place with a larger amplitude than any experienced during the holocene variations of dry and wet climates in the chinese loess plateau and in the loess belt of central europe have similar frequency it has been convincingly proved that the periodicity of the past gross climate changes agrees with that of the earth s orbital perturbations however while the amplitude of the orbital cycles and of the oceanic oxygen isotope variations is relatively uniform several of the cold climate episodes recorded on land appear more severe than the remainder they correspond to chinese loess units l1 l2 l5 l6 and l9 correlating with central european loess of cycles b c f h and j these units correspond to oxygen isotope stages 2 6 12 16 and 22 and to the weichselian saalian and elsterian ice advances in addition chinese loess layers l13 l15 wl1 wl2 wl3 and wl4 appear to represent exceptionally dry and cold episodes apparently correlative with the inter bavelian cooling and with menapian eburonian and praetiglian glacials of the rhine delta based on this observation we propose to distinguish within the last 2 5 m y ten megacycles describe them in the chinese loess sequences and name them in the order of increasing age mc1 mc10 each megacycle starts with an unusually thick loess unit interpreted as a deposit of an exceptionally severe glaciation and terminates with a cluster of well developed soils indicative of warm humid climates interrupted by relatively mild glacials the megacycles of the last 2 5 m y lasted between 200 and 340 millennia each with an average duration of 255 thousand years when correlated with the stratigraphic record of the chinese loess plateau the wurm terrace as well as the saale glacier advances the eem marine transgression the weichsel ice advance and the holocene correspond to a still incomplete megacycle mc1 the riss terrace the elster ice advance holstein transgression and subsequent mild and cool intervals ending with the schoningen interglacial sensu urban 1992 belong to the megacycle mc2 recognition of four megacycles within brunhes resolves the long standing discrepancy between the limited number of classical continental glacial and interglacial units and the frequent climate oscillations recorded in the deep sea sediments and the loess sequences only in the holsteinian and eemian interglacials was the crustal rebound delayed enough to permit oceanic transgressions reaching deep inland there is no apparent astronomic reason for the exceptional intensity and deep southward penetration of continental ice sheets during only some of the cold intervals since the differences are much more pronounced on land than in the ocean and since the major ice advances are closely linked with terraces it seems that the megacycles were preconditioned by tectonic movements intermittent pulses of rapid uplift of mountain ranges could have impacted climate worldwide by deflecting atmospheric circulation in the sense of ruddiman and raymo 1988 it is also probable that the tectonically changing shape of the sea floor sills reoriented the oceanic circulation which then could have affected plio pleistocene climates world wide the loess covered terraces in the lanzhou area demonstrate that the tectonic movements in the northern part of the tibet plateau correlate closely with the advances of continental ice in europe suggesting that the uplift of the tibet plateau significantly contributed to the gradual climate deterioration of the last million years

stable and clumped isotopes in shell carbonates of land snails cathaica sp and bradybaena sp in north china and implications for ecophysiological characteristics and paleoclimate studies knowledge of ecophysiological characteristics of different land snail species is crucial for defining climatic significance of snail faunal assemblages however little work has been done in this aspect hindering our obtaining unambiguous paleoclimatic information using these proxy indicators here we document for the first time the different ecophysiological characteristics of cathaica sp and bradybaena sp land snails using the stable isotopes and clumped isotope 47 of the shell carbonates the 47 derived temperatures for both species revealed a robust correlation with environmental temperatures moreover the temperatures for cathaica sp are 3 5 c higher than those for bradybaena sp land snails indicating different ecophysiological adaptations or growing seasons of the two species specifically cathaica sp snails prefer living in a warm humid summer whereas bradybaena sp snails are active in the relatively cool arid spring and or autumn the result testifies to the 47 in snail shell carbonates as a promising paleothermometer in monsoonal region and presents new insight into paleoclimatic explanation of these land snail species this finding highlights the importance of climatic seasonality in the changes of the faunal assemblages of land snails

spectral mixture modeling a new analysis of rock and soil types at the viking lander 1 site a viking lander 1 image was modeled as mixtures of reflectance spectra of palagonite dust gray andesitelike rock and a coarse rocklike soil the rocks are covered to varying degrees by dust but otherwise appear unweathered rocklike soil occurs as lag deposits in deflation zones around stones and on top of a drift and as a layer in a trench dug by the lander this soil probably is derived from the rocks by wind abrasion and or spallation dust is the major component of the soil and covers most of the surface the dust is unrelated spectrally to the rock but is equivalent to the global scale dust observed telescopically a new method was developed to model a multispectral image as mixtures of end member spectra and to compare image spectra directly with laboratory reference spectra the method for the first time uses shade and secondary illumination effects as spectral end members thus the effects of topography and illumination on all scales can be isolated or removed the image was calibrated absolutely from the laboratory spectra in close agreement with direct calibrations the method has broad applications to interpreting multispectral images including satellite images

between warm and cold impact of the younger dryas on human behavior in central europe abstract following a thorough review of high resolution environmental archives this paper aims at discriminating the factors determining the heterogeneous repercussion of the lateglacial younger dryas in central europe when examining the archaeological implications of human adaptation to the subsequent changes in the natural environment two divergent biotic regions are of special interest the north european plain and adjacent areas and the alpine foothills and surrounding mountain ranges in these regions two different archaeological technocomplexes traditions are found the tanged point complex and the curve backed point groups considering the distribution of the archaeological sites witnessing changes in the material culture and subsistence pattern the intensity of the environmental changes caused by the younger dryas is a decisive element settlement discontinuity during the younger dryas is questioned moreover the potential existence of established social networks between the two regions expressed by comparable developments such as microlithization is considered finally the authors assess whether the younger dryas acted as an accelerator or a brake in the process of regional diversification prior to the early mesolithic

climatic transfer function from quaternary molluscs in european loess deposits abstract correspondence and multiple regression analysis of terrestrial molluscs in the loess sections of achenheim alsace france has permitted the reconstruction of climatic variations during the last three glacial interglacial cycles back to 339 000 yr b p the sequence has been dated according to the specmap chronology of imbrie et al 1984 and the fossil faunas have been calibrated in relation to recent assemblages sampled in defined ecological conditions in sweden and france transfer functions that relate the abundances of different species to climate allow the reconstruction of temperature and precipitation estimates for the coldest february and warmest august months in present day alsace were obtained and variations in temperature between 13 and 2 c in winter and 10 and 17 c in summer were determined these results are consistent with those yielded by transfer functions using other continental fossils estimates differ for past precipitation summer precipitation is always less than present with values between 50 and 78 mm while modern august values are 76 mm higher winter estimates are always higher than the present mean between 76 and 33 mm while the recent february value is 34 mm comparisons between cycles show that the climatic patterns described for one cycle cannot be strictly applied to the others comparisons have been made with the pollen stratigraphy of la grande pile the nearest quantified sequence to achenheim and with some atlantic cores in order to study the magnitude of deviations from modern mean values of the climatic parameters

mollusk record of monsoon variability during the l2 s2 cycle in the luochuan loess sequence china abstract molluscan changes that occurred in china over the s2 l2 upper middle pleistocene series may be caused by monsoon variation study of terrestrial mollusks from the loess sequence in luochuan gathered in ecological groups according to the moisture and temperature requirements of the identified species indicates alternating strengthened summer and winter paleomonsoons between 130 000 and 244 000 yr the four occurrences of species currently distributed in s e china in the sequence indicate that the climate conditions were warmer and wetter than today between about 242 000 and 233 000 yr at about 210 000 164 000 and 140 000 yr the main occurrence of xerophilous taxa at about 180 000 154 000 and 138 000 yr is interpreted as indicating a drier environment than today such suggestions are in agreement with other proxy data such as grain size distribution higher numbers of individuals in the different ecological groups from the s2 l2 sequence indicate more favorable general environmental conditions than in the youngest s1 l1 this may agree with an increase in the regional aridity since 500 000 yr deduced from the study of the eolian flux in the northwestern pacific downwind from china

high resolution proxy record of the environmental response to climatic variations during transition mis3 mis2 and mis2 in central europe the loess paleosol sequence of katymar brickyard hungary abstract according to the findings of a complex radiocarbon dated sedimentological geochemical anthracological phytolite malacological study implemented on an open 1036 cm wind blown sand loess sandy loess and fossil soils profile of western part of brickyard at katymar village in hungary increased boreal mixed leaved forest steppe and temperate grassland cover characterized the interstadials in the se great hungarian plain during the terminal phase of mis3 stage and mis2 stage these interstadials correlate well with the dansgaard oeschger do interstadials 8 7 6 5 4 3 2 and the post lgm warm interval do1 seen in the greenland ice core oxygen isotope records intervening cold phases on the other hand their start correlating with heinrich event 1 2 3 4 and the lgm these data overall confirm that millennial scale climate variability during mis3 and mis2 stages had profound effect on the terrestrial ecosystems in the continental interior of se europe leading to periodic mixed leaved boreal forest steppe within mosaic structure expansions in the interstadias and cold steppe taiga and tundra like spots mosaic and mixed vegetation expansion in the stadial phases 1400 1500 year long drier interstadial and humid extended vegetation covered stadial periods interchanged at katymar sequence therefore the vegetation and fauna development was different from the atlantic and central european schemes and inferred an independent local and regional south carpathian basin trend

the crvenka loess paleosol sequence a record of continuous grassland domination in the southern carpathian basin during the late pleistocene abstract in this study we compare two independent paleoenvironmental proxies for a loess sequence in northern serbia in the southern carpathian basin novel n alkane biomarkers and traditional land snail assemblages both are associated with other more widely used proxy data for loess sections such as environmental magnetism grain size and geochemical indices together these paleoenvironmental proxy records provide evidence for the continued dominance of grasslands during the late pleistocene in the southern carpathian basin it is contrary to other european loess provinces which are characterized by high diversity of late pleistocene environments ranging from tundra like to deciduous forest habitats these findings highlight the southeastern part of carpathian basin as an important but still insufficiently investigated biogeographical refugium and biodiversity preservation zone the reason for this is a mostly stable paleoclimate for much of the late pleistocene

malacological and sedimentological evidence for warm glacial climate from the irig loess sequence vojvodina serbia four loess units and three paleosol layers are preserved in the irig brickyard vojvodina serbia amino acid geochronology provides stratigraphic correlations between loess units v l1 and v l2 at the irig section with loess of glacial cycles b and c respectively described from other central european localities luminescence dating results for the upper loess layers v l1l1 and v l1s1l1 confirm the geological interpretations although in samples below paleosol v l1s1s2 the age increase with depth is less than in our proposed age model magnetic susceptibility and sedimentological evidence from the irig loess paleosol sequence show general similarities with the mis 6 1 pattern of the specmap oxygen isotope curve malacogical investigations at the irig site reveal the continuous presence of the chondrula tridens and helicopsis striata faunal assemblages throughout the last glacial and final part of the penultimate glacial loess the loess snail fauna which is characterized by the complete absence of cold resistant species suggests a stable dry and relatively warm glacial climate compared with other central european loess localities furthermore these data suggest that the southern slope of fruska gora was a refugium for warm loving and xerophilus mollusc taxa during the otherwise unfavorable glacial climates of the late pleistocene

pleistocene holocene transition in benelux in benelux belgium the netherlands and luxembourg considerable progress in late glacial and early postglacial archaeological and environmental research has been made during the last decade a substantial part of this paper discusses new evidence on the chronology of the industries which occupied the southern part of benelux dating the occupations from the sandy north is still problematic long after the glacial maximum during which the area remained uninhabited the south of benelux was visited by magdalenian hunter gatherers while hamburgian settlements were present in the north the significance of the continental creswellian is debated during the allerod interstadial federmesser groups occupied most of the area abandoning it with the onset of the younger dryas the presence of the ahrensburgian during that stadial may have been punctuated new elements were introduced and were maintained during the development of the preboreal early mesolithic which eventually colonised the entire region throughout this sequence changes in material culture and related subsistence activities are evident in view of the major problems concerning the quality of the chrono ecological data this paper can only suggest provisional explanations in terms of human reactions to changing environmental conditions

mis3 2 millennial oscillations in greenland dust and eurasian aeolian records a paleosol perspective abstract since their discovery the abrupt climate changes that punctuated the last glacial period 110 6 14 62 ka have attracted considerable attention originating in the north atlantic area these abrupt changes have been recorded in ice marine and terrestrial records all over the world but especially in the northern hemisphere with various environmental implications ice core records of unprecedented temporal resolution from northern greenland allow to specify the timing of these abrupt changes which are associated with sudden temperature increases in greenland over a few decades very precisely the continental records have so far been mainly interpreted in terms of temperature precipitation or vegetation changes between the relatively warm greenland interstadials gi and the cooler greenland stadials gs here we compare records from greenland ice and northwestern european eolian deposits in order to establish a link between gi and the soil development in european mid latitudes as recorded in loess sequences for the different types of observed paleosols we use the correlation with the greenland records to propose estimates of the maximum time lapses needed to achieve the different degrees of maturation and development to identify these time lapses more precisely we compare two independent ice core records 18 o and dust concentration indicating variations of atmospheric temperature and dustiness in the greenland area respectively our method slightly differs from the definition of a gi event duration applied in other studies where the sharp end of the 18 o decrease alone defines the end of a gi we apply the same methodology to both records i e the gis are defined to last from the beginning of the abrupt 18 o increase or dust concentration decrease until the time when 18 o or dust recur to their initial value before the gi onset determined both visually and algorithmically and compare them to published estimates of gi timing and duration the duration of the gi and consequently the maximum time for paleosol development varies between 200 and 4200 years when visually determined and between 200 and 4800 years when estimated algorithmically for gi 17 to 2 i e an interval running from 60 ka to 23 ka b2k age before 2000 ad furthermore we investigate the abruptness of the transition from stadial to interstadial conditions which initiates the paleosol development the average transition duration is 55 4 16 1 56 8 19 6 years when determined visually and 36 4 13 4 60 00 21 2 years when determined algorithmically for the 18 o dust concentration the 18 o increases correspond to a mean temperature difference of 11 8 c on the top of the greenland ice sheet associated with substantial reorganizations of the ecosystems in mid latitude europe

biogeography of the pleistocene pleniglacial malacofaunas in europe stratigraphic and climatic implications abstract as determined by lozek malacological associations are significant of a particular vegetal environment in quaternary sequences different types of associations are recognized which can be assimilated to the present types of malacofaunas there are associations of grass group of forest group and of the ecotone of these two biogeographical entities on the european scale in pleistocene sequences the interglacial faunas indicate similarly the same differences as today being of stratigraphic interest on the contrary pleniglacial faunas which are mainly preserved in the loess belt seemed not interesting for stratigraphy since they indicate more generalized and more homogeneous conditions moreover they are composed of few species which for the most part had their distribution area destroyed by the ice cap advance yet the global analysis of pleniglacial biome faunas by ecological biogeographical approach provides a particular stratigraphic element which allows to determine stratigraphic entities provinces or domains in accordance with sedimentary interpretations so for quaternary pleniglacial faunas the biozone concept is efficiently supplied by ecostratigraphy consequently to a review of european localities it appears that the distribution of pleniglacial malacofaunas is mainly controlled by precipitations so the variations which are recorded in some privileged deposits as i e achenheim sequence in alsace france indicate variations through time of eastern limit of oceanic facies and western limit of continental facies of the climate

pleistocene climates in china dated by magnetic susceptibility the magnetic susceptibility of loess and interbedded soils in central china varies with the degree of pedogenesis and serves as a proxy measure of climate the concentration of magnetic minerals in the sediment is inversely proportional to sedimentation rates throughout the brunhes epoch susceptibility measurements combined with the reversal stratigraphy provide a time scale that is independent of astronomic chronology on this scale the susceptibility record closely parallels the oxygen isotope fluctuations in deep sea sediments suggesting a close interdependence of the chinese dust falls the volume of land based ice and global climate

loess is not just the accumulation of dust most regrettably there is much misuse of terminology in connection with the concept of loess and the interpretation of its origin people often speak and write incorrectly about loess accumulation even loess specialists who are aware of the fact that loess as a concept has to satisfy at least 10 criteria loess is not simply dust carried and deposited by wind dust only becomes loess after the passage of a certain amount of time in a given geographical zone i e only through diagenesis in certain ecological environments to state that loess is of aeolian origin is an oversimplification and an incorrect definition because an aeolian origin applies only to the dust from which the loess has been formed we are aware of the fact that airborne dust cannot be transformed into loess in every geographical environment but only under those conditions typical of semi arid grassland or steppe or forested steppe the process primarily occurs where the rate of dust accumulation exceeds sheet wash or weathering soil formation rates if the rate of dust accumulation is less than that of surface erosion or of soil biogenetic processes the dust then develops into soil or through intensive weathering and increased precipitation into loam or clay only part of the aeolian dust transported and deposited in a zone suitable for loess formation remains there permanently and is transformed in situ into loess dust not affected by diagenesis is usually further transported by snowmelt or rainwash and is only transformed into loess after it has been redeposited the loess itself however is easily erodible and its minerals are readily reworked and reaccumulated and given the appropriate conditions it readily undergoes diagenesis again we do not always have sufficient evidence to determine whether a given loess body is of primary or secondary origin traditionally the minerals making up primary loess have been regarded as originating in dust accumulated by aeolian processes secondary loess by contrast is different from typical loess in many ways and it is not unusual to find various loess series in which superimposed dust fractions have been transformed into loess by different processes recently we have observed that the origin of various types of loess is governed by differences in litho ecological conditions rather than by the way in which the mineral material from which the loess is derived dust has been primarily accumulated loessification is therefore determined by environmental conditions

imprint of north atlantic abrupt climate changes on western european loess deposits as viewed in a dust emission model abstract western european loess sequences of the last glaciation 100 000 15 000 years bp exhibit strong cyclic variations of the sedimentation rate which are coeval to the greenland stadial interstadial cycles and the heinrich events these north atlantic rapid climate changes appear thus as a potential cause for the sedimentation variations via changes in dust intensity cycle here we make a first step in testing this hypothesis by modelling the impact of the north atlantic abrupt climate variations on dust emission our dust emission calculations use meteorological fields generated by the lmdz atmospheric general circulation model at a resolution down to 60 km over western europe three numerical experiments are run representing a greenland stadial an interstadial and a heinrich event orbital parameters and ice sheet configuration correspond to conditions from marine isotope stage 3 60 000 25 000 years bp a period characterized by strong millennial scale climate variability the only differences we impose in the boundary conditions regard the north atlantic surface temperature and sea ice cover in the latitudinal band 30 63 n the changes in wind precipitation soil moisture and snow cover from one simulated state to another result in small differences in dust emission intensity in contrast when the inhibition of the aeolian erosion by vegetation is taken into account the dust fluxes for the cold climate states greenland stadial and heinrich event become generally more than twice higher than those for the relatively warmer greenland interstadial in agreement with the loess data these results support the hypothesis that the north atlantic millennial scale variability is imprinted in western european loess profiles and point to vegetation changes as the main factor responsible for millennial scale sedimentation variations an analysis for the english channel and southern north sea areas major potential dust sources shows that the seasonality of dust emission is not controlled by the wind speed as in modern large deserts but by the surface conditions consequently the dusty season lasts from late winter to early summer with maximum activity in april may and is shifted towards summer when the climate is colder

a direct link between the china loess and marine δ 18 o records aeolian flux to the north pacific most studies of quaternary climates conducted during the past 150 years have focused on glacial sequences and for the past 25 years marine sediments have provided significant further understanding of glacial and interglacial palaeoclimates an important goal of palaeoclimatology however to link the well known detailed continental records to marine records of similar resolution has yet to be realized the classic loess sequences of china provide an apparently continuous record of continental climate over the past 2 4 million years1 2 the oxygen isotope 18o timescale developed from the marine record3 gives us a global chrono stratigraphy of late pleistocene climates previously it has been suggested in studies of the aeolian component in pelagic sediments that it may be possible to link these two records directly by finding a suitable core from the north west pacific downwind from china4 5 here we report the results of such an effort for core v21 146 fig 1 and tie the last 500 000 years of the chinese loess soil sequence directly to the 18o timescale and in so doing refine the dating of regional loess and soil horizons

a new molluscan record of the monsoon variability over the past 130 000 yr in the luochuan loess sequence china this paper presents a new record of monsoon changes that occurred in china during the late pleistocene study of terrestrial mollusks from the loess sequence in luochuan indicates alternating strengthened summer and winter paleomonsoons these variations based on the content of xerophilous hygrophilous and oriental species are in very good agreement with the variation inferred from pedology sedimentology and climate modeling the three occurrences of currently southeastern species in the sequence indicate that the climate conditions were warmer and wetter than today at about 88 60 and 10 ka the main occurrence of xerophilous taxa between 75 and 65 ka is interpreted as drier than today in agreement with other proxy data these results demonstrate that fossil terrestrial mollusk data can provide reliable information on past monsoon variability in asia

environmental conditions framing the first evidence of modern humans at tam pa ling laos a stable isotope record from terrestrial gastropod carbonates abstract mainland southeast asia is a key region to interpret modern human migrations however due to a scarcity of terrestrial proxies environmental conditions are not well understood this study focuses on the tam pa ling cave site in northeast laos which contains the oldest evidence for modern humans in indochina dating back to mis 4 70 8 ka snail remains of camaena massiei found throughout the stratigraphic sequence contain a valuable oxygen and carbon isotope record of past local vegetation and humidity changes our data indicate that before the last glacial maximum lgm northeast laos was characterized by a humid climate and forested environments with the onset of the lgm a major climatic shift occurred inducing a sharp decrease in precipitation and a significant decline in woodland habitats in favor of the expansion to more open landscapes only during the holocene did forests return in northeast laos resembling present conditions the first homo sapiens arriving in indochina therefore encountered landscapes dominated by woodlands with a minor proportion of open habitats

dating the trollesgave site and the bromme culture chronological fix points for the lateglacial settlement of southern scandinavia abstract the bromme culture belongs to the lateglacial the period when people settled in the recently deglaciated southern scandinavia until now there have been only a few imprecise fix points relating to the chronological position of this archaeological culture this situation can now be improved with the aid of research results from a bromme culture settlement at trollesgave in se denmark using pollen and plant macrofossil data lateglacial lacustrine deposits containing waste material from the settlement can be assigned to the end of the climatically mild allerod period a series of 14 c dates establishes the age of the settlement as c 10 826 49 14 c years bp 12 871 12 590 cal yr bp by correlation with climate data from the greenland ice cores the occupation can be assigned to the early part of the cold climatic zone gs 1 thus demonstrating that the global ice core climate zones are not absolutely synchronous with the regional division into biozones

holocene environmental signals from mollusk assemblages in burgundy france abstract the malacofaunas of burgundy france reflect changes in climate and the activities of man during the holocene statistical analyses based on the shannon diversity index and correspondence analysis are used to describe the mollusk assemblages in a composite sequence based on three well dated sites the variation demonstrated by the mollusks suggests that a two step warming took place between 10 000 and 9000 and 8000 and 6000 yr b p in relative agreement with the timing of the deglaciation in the tropical atlantic ocean proposed by mix and ruddiman 1985 quaternary science reviews 4 59 108 high humidity partly associated with widespread inundations of the valleys between 10 000 and 8000 yr b p may be related to estimated variations in the rate of freshwater discharge to the atlantic ocean reported by fairbanks 1989 nature 342 637 642 the increasing impact of human activities on the environment during the past 2000 yr is indicated by the low diversity of the mollusk assemblages demonstrating the need for careful interpretation of the youngest holocene sediments in this region

palaeoecology of quaternary periglacial environments during ois 2 in the forefields of the salzach glacier upper austria palaeopedological sedimentological and palaeoecological investigations were carried out on the pleniglacial loess deposits of duttendorf austria in the area of the pleistocene salzach glacier detailed insights into the past climate topography and vegetation especially during the oxygen isotopic stage 2 ois 2 were obtained according to the results it seems that alluvial processes played a more important role for the genesis of the loess deposits during the late glacial maximum lgm than previously assumed the pollen record plant macro remains and malaco fauna yield the occurrence of hygrophilous taxa as well as of water plants by consequence the sediment can be regarded as alluvial loess furthermore the results show that the landscape corresponded not only to a cold and dry loess steppe environment but was also partly influenced by humid conditions and that probably even small water bodies may have existed

surface properties of the pettit wind streak on mars implications for sediment transport abstract pettit crater 12 n 174 w is associated with a complex wind streak consisting of both type i bright streak and type ii dark streak materials broadband albedo measurements of the streak indicate a minimum of 20 and a maximum of 32 with 27 on the surrounding plains the darkest materials have the highest thermal inertias which can be related to an effective grain diameter typical of medium sand most of the dark streak materials have thermal inertias representative of fine sand the material most easily set in motion by the wind on mars the bright portions of the streak have thermal inertias higher than that of the surrounding plains the bright streak values are representative of very fine sand differences between temperatures measured at 11 and 20 m indicate there is no difference in the areal abundance of unresolved high thermal inertia materials e g blocks bedrock between the pettit streak and the surrounding plains the dark streak material is consistent with models involving sand saltation and transport but the bright streak thermal inertia is not consistent with a volumetrically significant enhancement of unconsolidated dust in the streak

statistical analyses of loess molluscs for paleoecological reconstructions abstract molluscs remains are generally numerous in loess sequences and a rich literature deals with them but since the proposal of lozek s method which is widely used in quaternary molluscan studies no new methods have been proposed apart from some adjustments it is a fundamental fact that to propose a new approach implies consideration of the studied material with other concepts nevertheless to renew existing methods and concepts needs the opportunities of new techniques new physical supports but also depends on the scientific hard core of scientists the generalization and the rising power of computers and micro computers was one opportunity for the geosciences more precisely the renewal of concepts in paleontology leads to new hard cores based on multidisciplinary approaches implying a quantification of data that is the reason why morphometry appears in evolution studies quantitative paleoclimatology firstly developed on marine micro organisms quantitative paleoecology to characterize the different type of associations quantitative biostratigraphy all these approaches widely using multivariate methods concerning quaternary molluscs i have attempted to develop new concepts because these organisms allow precise studies dealing among others with evolution biogeography climatology and biostratigraphy they are generally present in the loess sequences which record several climatic cycles that is to say variations in geosphere biosphere relations consequently analyses of loess molluscs are able using statistical analyses to contribute to the understanding of the geosphere biosphere system

danube loess stratigraphy towards a pan european loess stratigraphic model abstract the danube river drainage basin is the second largest river catchment in europe and contains a significant and extensive region of thick loess deposits that preserve a record of a wide variety of recent and past environments indeed the danube river and tributaries may themselves be responsible for the transportation of large volumes of silt that ultimately drive loess formation in the middle and lower reaches of this large catchment however this vast loess province lacks a unified stratigraphic scheme european loess research started in the late 17th century in the danube basin with the work of count luigi ferdinand marsigli since that time numerous investigations provided the basis for the pioneering stratigraphic framework proposed initially by kukla 1970 1977 in his correlations of loess with deep sea sediments loess palaeosol sequences in the middle and lower reaches of the danube river basin were a key part of this framework and contain some of the longest and most complete continental climate records in europe covering more than the last million years however the very size of the danube loess belt and the large number of countries it covers presents a major limiting factor in developing a unified approach that enables continental scale analysis of the deposits local loess palaeosol stratigraphic schemes have been defined separately in different countries and the difficulties in correlating such schemes which often change significantly with advances in age dating have limited the number of basin wide studies a unified basin wide stratigraphic model would greatly alleviate these difficulties and facilitate research into the wider significance of these loess records therefore we review the existing stratigraphic schemes and define a new danube basin wide loess stratigraphy based around a synthetic type section of the mosorin and stari slankamen sites in serbia we present a detailed comparison with the sedimentological and palaeoclimatic records preserved in sediments of the chinese loess plateau with the oxygen isotope records from deep sea sediments and with classic european pleistocene stratigraphic subdivisions the hierarchy of danubian stratigraphic units is determined by climatically controlled environmental shifts in a similar way to the chinese loess stratigraphic scheme a new unified danube loess stratigraphic model has a number of advantages including preventing confusion resulting from the use of multiple national schemes a more transparent basis and the potential to set pleistocene palaeoenvironmental changes recorded in the danube catchment area into a global context the use of a very simple labelling system based on the well established chinese loess scheme facilitates interpretation of palaeoenvironmental information reported from the danube basin loess sites in a wider more accessible context that can be readily correlated world wide this stratigraphic approach also provides for the first time an appropriate framework for the development of an integrated pan european and potentially pan eurasian loess stratigraphic scheme

simulation of intense monsoons under glacial conditions paleoenvironmental and paleoclimatological proxy data indicate that strong continental monsoons took place under glacial conditions during marine isotopic stage 6 5 175 ka bp so far no climate model has explored the possible coexistence of glacial conditions at mid and high latitudes and of interglacial monsoons in the tropics here we use an atmospheric general circulation model and clearly demonstrate that high insolation can generate increased monsoon activity even with surface glacial conditions our experiments show that indian and african monsoons at 175 ka were stronger than nowadays and induced an increase in outflow of the nile river to the mediterranean sea this freshwater supply combined with the local low glacial evaporation may explain the stagnation of the eastern mediterranean sea leading to the deposit of sapropel s6 our simulations show also increased surface winds in the northern atlantic and pacific oceans which may have affected the bioproductivity in these areas

martian intracrater splotches occurrence morphology and colors abstract martian intracrater splotches and related streaks are studied with global data on their occurrence and regional data on color and morphology the fraction of craters with splotches is greatest at high latitudes splotch occurrence is not strongly correlated with surface properties such as albedo and thermal inertia except where these correlate with substantial sediment cover large numbers of splotches are or include dunes especially at high southern latitudes color data show that the dune and nondune materials in splotches are part of one related group of materials that may be of similar composition but varying particle sizes the color data also show that some streaks are simply material deflated from splotches and mixed with local plains material while other streaks are more complex and may involve erosion of thin surface layers by material blown from the splotches splotches appear to be trapped eolian sand but probably have been formed by a great variety of mechanisms a large percentage of craters with splotches show evidence of complex histories of sediment deposition and erosion many splotches may be lag deposits from erosion of regional sediment cover present sediment budgets in splotches are not known but there is some evidence for loss of material and no evidence for resupply from outside the craters

hunter gatherer responses to the changing environment of the moervaart palaeolake nw belgium during the late glacial and early holocene abstract this paper presents new geo archaeological perspectives on the late glacial and early holocene human occupation around a large palaeolake the moervaart palaeolake 25 km 2 intensive fieldwork using invasive and non invasive survey techniques combined with modelling of the palaeotopography and palaeogroundwater and multi proxy palaeoecological analyses have resulted in a detailed reconstruction of the landscape during the final palaeolithic and early mesolithic occupation of the area a major shift in the occupation from the federmesser culture to the early mesolithic was contemporaneous with a sudden and drastic change in the palaeohydrology of the area between ca 13 300 and 13 000 cal bp end of allerod which coincided with a short but abrupt cooling event known as the intra allerod cold period iacp gi 1b it is assumed that this event triggered the sudden drying up of the moervaart palaeolake and surrounding ponds which until then had provided federmesser hunter gatherers with extensive and fertile grounds for hunting gathering and drinking water the population decline which followed this hydrological event was reinforced by the prevailing cold and harsh conditions of the younger dryas and probably lasted until the pre boreal hunter gatherers returned to the area in the boreal now settling along the proximal floodplain regions of a meandering channel which was connected with the southern scheldt river

african monsoons an immediate climate response to orbital insolation the croll milankovitch astronomical theory of climate1 3 has received strong support from the evidence of a linear climatic forcing by obliquity and precession although nonlinearity had to be assumed for eccentricity4 5 moreover interglacials have appeared to be controlled by the orbital insolation6 although a phase shift of 6 000 5 000 yr is seen between an astronomical climate index and terrestrial climate indicators dominated by the northern ice sheet dynamics climate proxy data of low latitudes are less directly dependent on the ice sheets here it is shown that during the past 464 000 yr african monsoons signalled by the east mediterranean sapropels were heaviest always and only when a northern summer monsoon index computed from the orbital variation of insolation reached maximum values this occurred during all the interglacials but also twice during glacial periods thus tropical aridity is not the single climatic pattern of glacial periods an immediate terrestrial climate response to orbital variations of insolation is established

mineralogical and colour changes of quartz sandstones by heat seven german and three hungarian monumental sandstones have been tested in laboratory conditions to analyse the effect of heat the studied quartz sandstones have a wide range of cements and grain sizes including silica carbonate clay and ferrous mineral cemented varieties of fine medium to coarse grained types cylindrical specimens were heated up to 150 300 450 600 750 and 900 c in an oven the mineralogical and textural changes were recorded and compared by using microscopy xrd dta dtg and sem colours and colour differences a b l values were also measured and evaluated colour changes are related to mineral transformations the most intense colour change is caused by the oxidation of iron bearing minerals to hematite that takes place up to 900 c when temperature increases the green glauconite becomes brownish while the chlorite changes to yellowish at first the colour of burnt sandstone is not a direct indicator of burning temperature since there are sandstones in which the burnt specimens are lighter and less reddish than the natural ones porosity increase is related to micro cracking at grain boundaries above 600 c and within the grains at and above 750 c and mineral transformations the clay mineral structure collapses at different temperatures kaolinite up to 600 c chlorite above 600 c and leads to a slight increase in porosity the most drastic change is observed in calcite cemented sandstones where the carbonate structure collapses at 750 c and cao appears at 900 c subsequently it is transformed to portlandite due to absorption of water vapour from the air this leads to the disintegration of sandstone at room temperature a few days after the heat shock

late pleistocene climate record in the eustis loess section nebraska based on land snail assemblages and magnetic susceptibility abstract based on multivariate analysis of mollusk assemblages and magnetic susceptibility of the eustis section in western nebraska the climate of the peoria loess steppe was relatively mild and in terms of annual precipitation relatively moist during the advance stages of woodfordian ice it was cold and dry during ice retreat the diversity and composition of mollusk species indicates that the extreme cold and dry climate was reached during the late phase of peoria time in mollusk zone mz3 although soil moisture during the growing season at that time was high the growing season was short and annual precipitation totals were low low values of magnetic susceptibility imply relatively rapid dust deposition during this interval judging from the current ecological tolerance of the species no closed forest existed in the area only scattered shrubs or isolated tree stands may have been present the late peoria mz3 assemblage compares favorably with the columella fauna of europe in contrast the early peoria mollusk assemblages mz1 and mz2 compare well with the european pleniglacial pupilla associations based on available 14 c dates from the studied region and on assumed relation of magnetic susceptibility to sedimentation rates the estimated age of the mz1 and mz2 zones is 24 000 to 16 000 yr whereas that of mz3 is 16 000 to 12 000 yr

reponses des malacofaunes terrestres quaternaires aux contraintes climatiques en europe septentrionale abstract quaternary land snails show two major responses to climatic variations emigration and ecophenotypism the former is the case of the great majority of stenotopic species examples of migration are determined through the study of malacological associations in northern france cooler phases are indicated by the immigration and development of nordic and alpine species of which the area of distribution was invaded by ice by contrast interglacial temperate periods corresponding to a recolonization of free environments are indicated by the immigration of forest or semiforest thermophilic species ecophenotypism concerns some eurythermal species they display morphological variations of the shell mainly variations in size which parallel climatic variations in pupilla muscorum the shell is large when the climate is cold and small when it is temperate examples of migration and ecophenotypism are provided by joint studies of the malacological associations and pupilla muscorum in the achenheim site alsace france

malacological sequence of weichselian mis 5 2 loess series from a profile in grodzisko dolne southern poland and its palaeogeographic significance abstract abundant and diverse molluscan assemblages have been identified in a loess site in grodzisko dolne the profile is located in south eastern poland within a loess belt covering the kolbuszowa plateau in the exposed sequence which is 9 m thick two loess covers underlain and divided by initial soil sequences have been distinguished numerous molluscan remnants were found throughout the entire profile the malacological analysis enabled four faunal assemblages to be distinguished pupilla fauna succinella fauna arianta fauna and mixed fauna their sequence in the vertical profile is indicative of environmental changes especially concerning climate and substrate humidity the occurrence of malacofauna within the loess and soil sequence which corresponds to the early glacial and early pleniglacial mis 5 and 4 is particularly interesting the presence of molluscan shells in loesses of this age has been noted in few sites in europe the faunal studies and analyses performed in the grodzisko dolne site indicate the major importance of this profile in the research of regional differences in weichselian loess covers in europe

paleoclimatology of the achenheim series middle and upper pleistocene alsace france a malacological analysis abstract the loessic series of achenheim show an uninterrupted stratigraphical sequence dating from the middle and upper pleistocene they contain very abundant paleontological material especially land snails statistical analysis of the malacofaunas multivariate methods has allowed the reconstruction of the climatic evolution of that site during this period five cycles have been recognized which correspond to the glacial cycles b c d e and f comparison with the section of cerveny kopec czechoslovakia indicates the existence of a major climatic event during the pleniglacial of cycle d with a general expansion of the loess steppe in europe an environment which later never appeared in alsace the analogy of the climatic sedimentary sequences of cycle c suggests that alsace and central europe belong to the same geographical entity the development of alsace to an intermediary status between northwestern and central europe

a lateglacial archaeological site in the far north west of europe at rubha port an t seilich isle of islay western scotland ahrensburgian style artefacts absolute dating and geoarchaeology the exact pattern process and timing of the human re colonization of northern europe after the end of the last ice age remain controversial recent research has provided increasingly early dates for at least pioneer explorations of latitudes above 54 n in many regions yet the far north west of the european landmass scotland has remained an unexplained exception to this pattern although the recently described hamburgian artefacts from howburn and an assemblage belonging to the arch backed point complex from kilmelfort cave have established at least a sporadic human presence during earlier stages of the lateglacial interstadial we currently lack evidence for younger dryas greenland stadial 1 gs 1 activity other than rare stray finds that have been claimed to be of ahrensburgian affiliation but are difficult to interpret in isolation we here report the discovery of chipped stone artefacts with technological and typological characteristics similar to those of the continental ahrensburgian at a locality in western scotland a preliminary analysis of associated tephra pollen and phytoliths along with microstratigraphic analysis suggest the artefacts represent one or more episodes of human activity that fall within the second half of gs 1 and the preboreal period 2015 the authors journal of quaternary science published by john wiley sons ltd

a sealed flint knapping site from the younger dryas in the scheldt valley belgium bridging the gap in human occupation at the pleistocene holocene transition in w europe based on the evidence of a recently excavated sealed site situated at ruien rosalinde in the belgian scheldt valley the response of hunter gatherers to changing climate at the transition from the temperate allerod to the cold younger dryas is discussed radiocarbon dated to the end of the allerod or the very beginning of the younger dryas the site of ruien provides the earliest evidence of a refined lithic technology characterized by the use of a soft stone hammer and the production of straight and regular blade let s from intensively prepared cores with two opposite platforms and sharp striking angles in the course of the younger dryas and early pre boreal this knapping method will become standard all over europe from the tanged point technocomplex in the north to the epi laborian in the south it contrasts sharply with the knapping style of previous lithic traditions such as the late federmesser azilian and bromme technocomplexes which was much less elaborated and mainly oriented towards the knapping of short irregular blades with a hard stone hammer this apparently abrupt technological change was also accompanied by increased raw material procurement networks extending over up to 250 km and a marked microlithisation of the hunting equipment finally the site of ruien is also important as it demonstrates the limited archaeological visibility of younger dryas sites explaining the scarcity of such sites within western europe

characterization of loess in central spain a microstructural study the purpose of this paper is to characterize the materials developed in the middle tajo river valley central spain these sediments are loess the characterization of which has not been reported in the international bibliography the sediments are related to the next geological context and their characterization is indispensable to locate the said material in the adequate environment a few different methods have been employed in this study such as the pipette method for determining the grain size and separation of the light and heavy minerals of the sand fraction by using bromoform the mineralogical composition was determined by xrd and textural study was accomplished by sem edx the loessic materials are silt clay or sandy silt that are quite unstable the mineralogical composition shows quartz feldspar calcite and clay minerals some samples show gypsum this mineral and calcite present dissolution and stability problems the heavy minerals starting from the sand fraction are tourmaline zircon garnet staurolite sillimanite and biotite associations the studies carried out with sem show that the quartz grain surfaces present etch pits typical of the wind blown origin

molluscs and ostracods of the pleistocene loess deposits in the halych site western ukraine and their significance for palaeoenvironmental reconstructions abstract middle and late pleistocene loess palaeosol sequence mis 12 mis 2 from the halych site has been divided into four loess beds which represent different glacial periods and contain four interglacial pedocomplexes as well as numerous interstadial and interphase palaeosols long term interdisciplinary research which has been conducted in this site enables the detailed description of deposit lithology and precise determination of stratigraphic position of individual layers rich and diverse malacofauna occurs in loess deposits representing cold stages mis 12 mis 8 and mis 4 2 seven molluscan assemblages of diverse composition and structure have been distinguished additionally ostracod fauna from the deposits representing mis 8 is described faunal investigations enable the reconstruction of environmental changes during deposition of the studied sequence the obtained results indicate that the halych site may be considered as very important not only for the reconstruction of the pleistocene geological history in western ukraine but also for the studies of environmental conditions during the middle and late pleistocene in the whole of central and eastern europe

molluscs in loess their paleoecological significance and role in geochronology principles and methods abstract the malacofauna of genuine wind blown loess consists of a minor number of tolerant species occurring mostly in high amounts and reflecting open habitats with poorly developed calcareous soils it shows a rather uniform character in space and time distinctly differing from all present day assemblages of the temperate zone and thus indicating a very peculiar environment characteristic of the loess steppe in protected areas particularly on valley slopes the loess covers alternate with intercalations of slope sediments and soils including several other types of snail assemblages reflecting environmental changes in the course of the quaternary climatic cycle among these malacocoenoses the interglacial faunas are of prime biostratigraphic importance they are associated with strongly weathered forest soils and indicate woodland environments under very damp and warm climatic conditions transitional steppe and taiga assemblages occur in buried chernozem soils and in various slope sediments e g in the pellet sands overlying the interglacial soils and corresponding to early glacial periods although the fauna of proper loess shows a monotonous composition it is possible to distinguish several types of loess assemblages corresponding to minor facies changes of loess environments in time and space these are for example the pupilla helicopsis striata and columella faunas of central europe a peculiar marshland fauna characterizes the so called swamp loess deposited in ephemeral swamps in the marginal zones of the loess belt there occur also faunas partly differing from those of typical loess this is true particularly of the mediterranean region the most important contribution provided by molluscan faunas from the loess series is the evidence of the maximum number of climatic cycles during the quaternary period

loess biostratigraphy new advances and approaches in mollusk studies abstract since the beginning of the 20th century loess biostratigraphy has been strongly influenced by investigations of mollusks these shells constituting the major fossil remains found in loess sequences the earlier studies mostly involved identifying species and determining biozones or assemblages with regard to the presence or absence of key species using the classic concept of biozones although this provided accurate elements with which to define an indicative biostratigraphy the time resolution was not always sufficiently precise to connect those studies with the more recent and high resolution analyses that are now routine in quaternary investigations this paper reviews mollusk studies carried out in northern hemisphere loess sequences and shows that a consideration of them as both biostratigraphic and palaeoclimatic indices enhances their potential and opens up particularly interesting areas of research the first example demonstrates that the last glacial mollusk assemblages in north america show compositional similarities to those in europe the climatic interpretation however appears more restricted by local conditions the second example shows that climatic conditions can be used to infer variations in the composition of biozones and thus address the significance of the distributional pattern of key species the third example demonstrates the value of high resolution studies and the potential of comparing the results of mollusk analyses with other proxies as an underpinning of the biological interpretation finally the need for more high resolution investigations in both north america and asia is stressed

molluscan assemblages from the loess of north central china abstract although molluscan faunas are the most widespread fossil remains in the chinese loess there have been very few attempts to use their potential for climatic reconstruction or to develop ciimato stratigraphic schemes this paper reports assemblages of mollusca from three sites in the north and south central parts of the loess plateau and evaluates the uses of molluscan faunas as climatic proxies in the s 1 palaeosol the malan loess and s o palaeosol the molluscan sequence is compared with the record obtained from pedological and magnetic techniques the current study shows that major peaks in magnetic susceptibility thought to be due to pedogenesis under warm humid conditions can be matched by levels of high molluscan abundance the occurrence of a sharp molluscan peak within the malan loess otherwise only indicated by a slight increase in magnetic susceptibility is held to be due to the existence of a short lived humid episode and demonstrates the sensitivity of mollusca as indicators of relatively low magnitude climatic shifts not well indicated by other lines of evidence

late pleistocene intensification technologies in northern china intensification technologies used in late pleistocene northern china include microblades milling stones and pottery all of which have been implicated in development of agriculture in northern china perhaps influenced by the harsh climate of the younger dryas this paper examines the adaptive function of these technologies in the context of late pleistocene climate and environment it is proposed that microlithic technology was a tool of mobile foragers focused on hunting and the initial use of pottery was probably connected to bone grease production only milling stones were initially a plant oriented intensification technology but their sparse episodic appearance in the late pleistocene did not lead to persistent intensification involved in the development of agriculture it was only after the younger dryas in the context of improved holocene climate and greater primary productivity that these three technologies converged with changes in mobility to become part of the agricultural revolution in northern china

stable carbon and oxygen isotopic composition of modern land snails along a precipitation gradient in the mid latitude east asian monsoon region of china abstract the stable oxygen and carbon isotope composition 18oshell and 13cshell of land snail shells preserved in chinese eolian loess deposits have the potential to reconstruct past changes in the east asian summer monsoon easm since the late oligocene to assess the potential of 18oshell and 13cshell for the semi quantitative reconstruction of past variations of the easm we studied modern snails and the corresponding vegetation composition of three distinct ecosystems woodland grassland and mountains spanning a large rainfall gradient 178 1403 mm in the mid latitude east asian monsoon region the results show that different snail species in the three ecosystems have significantly different values of 18oshell and 13cshell the snails in woodland from the eastern plain area have significantly lower 18oshell and 13cshell values than those of snails in grassland from the chinese loess plateau and the snails from the qinba mountains region have values intermediate between the two systematic variations of the 13c of snail shells body tissues and local plants are evident along the rainfall gradient indicating that 13cshell is mainly influenced by the 13c of ingested plants which is controlled by the easm we confirm that 13cshell is a reliable precipitation proxy and we obtained a new empirical equation 13cshell 0 0030 0 0003 map 8 80 0 32 r 0 76 n 74 p

nature and distribution of surficial deposits in chryse planitia and vicinity mars color images of bright red dust deposits at the mutch memorial station were acquired at variable incidence angles during sol 611 subsolar longitude 70 northern spring season after removing effects due to atmospheric scattering and absorption the data were used to estimate the independent variables in the hapke 1986 photometric function in blue green and red coordinates the vector representing the space radiance factor of the landing site extracted from viking orbiter images acquired on sol 609 is separated by a euclidean distance of only 0 022 units and an angle of only 1 5 from the vector estimated from the station data for the orbiter lighting and viewing geometries this result implies that light reflected from dust exposures dominates the orbiter signal multiplicative and additive atmospheric terms cancel one another and surface roughness is a second order effect in the orbiter data dust radiance factors computed from station data are most like laboratory spectra for fine grained hawaiian palagonite and are indistinguishable from earth based spectra of classical bright areas color composites of orbiter images show that the dust is found immediately south of acidalia planitia and in association with topographic barriers such as craters and cliffs examination of viking infrared thermal mapper data shows that the dust deposits typically do not have distinctive thermal inertia signatures implying that the deposits are optically thick hundreds of micrometers but thinner than the diurnal thermal skin depth centimeters dark gray material with thermal inertia values 8 12 10 3 cal cm 2 s 1 2 k 1 indicative of sand grain sizes 0 5 1 5 mm dominates the acidalia planitia lowlands and parts of kasei vallis this material also occurs as dark streaks extending from craters in xanthe terra and oxia palus space radiance factors of dark gray material are similar to spectra of mafic rock mixed with a minor amount of palagonitelike material material that is darker than but just as red as the dust deposits occurs in lunae planum xanthe terra and oxia palus areas of intermediate elevation multiple phase angle orbiter images suggest that the dark red exposures are a mixture of bright red and dark gray materials with the dark red exposures being relatively rough at a subpixel scale as compared to exposures of the other two materials thus only two types of materials can be detected in the data covering the study area palagonitelike dust and mafic rock fragments thermal inertia values 4 8 10 3 cal cm 2 s 1 2 k 1 for the dark red material are consistent with the presence of fine to medium sand size particles 0 10 0 5 mm such material should be easily moved by winds the lack of aeolian features implies that the dark red deposits are not composed of loose material rather they are probably more eroded versions of blocky soil or duricrust cemented dust and rock fragments exposed at the station both bright red dust aeolian suspension load and dark gray materials saltation traction loads migrate over the dark red substrate the overall distribution of the surficial units is controlled by topography at a variety of length scales lower wind threshold friction velocities associated with higher atmospheric densities in lowlands keep dust from accumulating and duricrust from forming while higher threshold velocities in highlands lead to net accumulation of dust local topographic obstacles craters walls ridges perturb wind flow and lead to local accumulation or erosion at a variety of elevations in addition the bright red dust ubiquitously found between exposures of dark gray and dark red materials may accumulate as the wind velocity gradient decreases at the transition from smoother dark gray exposures to rougher dark red exposures the distribution of the materials must also be modulated by climatic variations induced by quasi periodic oscillations in obliquity eccentricity and spin axis direction constraining these surficial deposits to be 1 ma

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