intersections between wind regimes topography and sediment supply perspectives from aeolian landforms in central asia abstract the widespread aeolian deposits of the central asian steppes and piedmonts offer potential to better understand the dynamics of the major eurasian climate subsystems over quaternary timescales however current assumptions linking climate processes with aeolian activity remain poorly substantiated and potentially problematic emerging datasets suggest that loess accumulation rates and the timing of peak dust flux along the tien shan piedmont are highly variable between sites the degree to which desert dunes reflect wind regimes and therefore provide records of climate circulation is unknown and the presumed genetic link between the region s desert dunes and piedmont loess deposits remains hypothetical these uncertainties raise questions as to the nature of the relationship between aeolian flux deposition and palaeo climate here we investigate the relationship between wind regimes and the distribution morphology and timing of two aeolian landform types dunes and loess in the topographically diverse ili basin of southeast kazakhstan and western china we establish late holocene ages for three dune sites and one loess profile and infer that the location and morphology of these landforms can be used to test their genetic link with recent wind regimes we assess the morphologic characteristics of linear dunes at four sites using a semi automated mapping approach and analyse the variability in dune orientations with respect to sand shifting wind trajectories identified from meteorological reanalysis data for each site the most frequently occurring wind direction appears to be responsible for sediment supply while the strongest winds drive dune orientation wind orientations are strongly influenced by topography back trajectories incorporating dust transport and deposition potential to the loess site suggest both westerly and northerly delivery of fine grained material to the piedmont and that the most common source areas lie in regions where surface sediment contains a mixture of coarse and fine grained material to facilitate entrainment into suspension

penetration of atlantic westerly winds into central and east asia abstract the geographical position of the convergence zone where the western atlantic climate system meets the asian winter monsoonal system depends on their relative strength these individual strengths are determined by the intensities of the air pressure gradients over the north atlantic and the siberian high pressure cell respectively since the factors that forced those gradients varied throughout glacial interglacial cycles the location of the convergence zone should have moved accordingly both the grain size characteristics of wind blown sediments and climate modelling prove that the atlantic influence extended remarkably far eastward at times the northeastern tibetan plateau was at the cross road of western and monsoonal influences during the last glacial this region was dominated by an atlantic signal with millennial scale climatic oscillations that are similar to the north atlantic marine and greenland ice core records in contrast that same region was only under monsoonal influence during the last interglacial it implies that the atlantic winds penetrated more vigorously eastward in full glacial conditions than in interglacial conditions

the progressive evolution of a continental climate in southeast central european lowlands during the middle pleistocene recorded in loess paleosol sequences 1 abstract little is known about the long term quaternary climate evolution of central and south east europe because suitable terrestrial paleoenvironmental records are scarce we present a multiproxy record of loess paleosol sequences in the middle and lower danube basins over the past 700 k y in these lowlands the continentality of interglacial climate progressively increased during the middle pleistocene corresponding trends are seen in other climate prox ies in the same region and in the lowlands of the northern black sea but not or less clearly in climate archives from outside these lowlands we conclude that a small scale increase in paleoelevation of central european mountain ranges the alps carpathians and dinarides during the middle pleistocene might be the cause of the progressive increase in climate conti nentality of southeast european lowlands

aeolian dust in europe african sources and european deposits abstract a conceptual model is presented for the provenance and dispersal patterns of small dust that falls on europe generally its sources are in north africa and it is distributed across all europe several key sources can be distinguished sahelian dust comes largely from the old lake chad region this is a clay rich unimodal material saharan dust comes from the great sand sheets it contains small monomineralic particles and may have a bimodal size range three simple deposition zones can be recognised a d1a zone where sufficient dust is deposited to form a discrete soil layer not well classified as a rendoll in the extreme south of europe a d1b zone where the airborne dust simply provided a silty admixture to soil systems across middle europe and a northern zone d1c where the dust is a fugitive cloud but very occasionally forms noticeable deposits two particle formation methods can be noted particle control in sahelian dust is via the sedimentation in the original lake this gives an open structure which can be modelled using a simple monte carlo approach the open structure ensures that only small particles are produced size control is via particle packing a chipping mechanism can produce fine quartz particles from sandy deserts the aeolian energy is by and large not sufficient to cause major impact fracturing but small mineral chips can be produced in the small dust size fine and very fine silt which go into high level suspension and travel to europe and beyond the saharan material can have a wider more variable size distribution than the sahelian material the canary islands loess is largely sahelian material the cape verde islands deposits from the nearby sandy regions are saharan deposits large dust has fallen on europe and produced widespread loess deposits large dust is essentially an in continent deposit small dust comes from outside from africa

magnetostratigraphical dating of loess deposits in china the age of chinese loess deposits has long been disputed biostratigraphical and earlier magnetostratigraphical investigations placed the entire loess formation within the pleistocene the new palaeomagnetic measurements reported here on a bore hole section near lochuan shaanxi province suggest a clearly defined magnetic polarity zonation which extends below the olduvai subchron a late pliocene age of 2 4 myr is assigned to the oldest loess sediments measured the intensity variations of natural remanent magnetization nrm and low field magnetic susceptibility are indicative of climatic changes during loess deposition

age dating and the orbital theory of the ice ages development of a high resolution 0 to 300 000 year chronostratigraphy using the concept of orbital tuning a continuous high resolution deep sea chronostratigraphy has been developed spanning the last 300 000 yr the chronology is developed using a stacked oxygen isotope stratigraphy and four different orbital tuning approaches each of which is based upon a different assumption concerning the response of the orbital signal recorded in the data each approach yields a separate chronology the error measured by the standard deviation about the average of these four results which represents the best chronology has an average magnitude of only 2500 yr this small value indicates that the chronology produced is insensitive to the specific orbital tuning technique used excellent convergence between chronologies developed using each of five different paleoclimatological indicators from a single core is also obtained the resultant chronology is also insensitive to the specific indicator used the error associated with each tuning approach is estimated independently and propagated through to the average result the resulting error estimate is independent of that associated with the degree of convergence and has an average magnitude of 3500 yr in excellent agreement with the 2500 yr estimate transfer of the final chronology to the stacked record leads to an estimated error of 1500 yr thus the final chronology has an average error of 5000 yr

high resolution record of the environmental response to climatic variations during the last interglacial glacial cycle in central europe the loess palaeosol sequence of dolni věstonice czech republic abstract high resolution multidisciplinary investigation of key european loess palaeosols profiles have demonstrated that loess sequences result from rapid and cyclic aeolian sedimentation which is reflected in variations of loess grain size indexes and correlated with greenland ice core dust records this correlation suggests a global connection between north atlantic and west european air masses herein we present a revised stratigraphy and a continuous high resolution record of grain size magnetic susceptibility and organic carbon 13c of the famous of dolni vestonice dv loess sequence in the moravian region of the czech republic a new set of quartz osl ages provides a reliable and accurate chronology of the sequence s main pedosedimentary events the grain size record shows strongly contrasting variations with numerous abrupt coarse grained events especially in the upper part of the sequence between ca 20 30 ka this time period is also characterised by a progressive coarsening of the loess deposits as already observed in other western european sequences the base of the dv sequence exhibits an exceptionally well preserved soil complex composed of three chernozem soil horizons and 5 aeolian silt layers marker silts this complex is at present the most complete record of environmental variations and dust deposition in the european loess belt for the weichselian early glacial period spanning about 110 to 70 ka allowing correlations with various global palaeoclimatic records osl ages combined with sedimentological and palaeopedological observations lead to the conclusion that this soil complex recorded all of the main climatic events expressed in the north grip record from greenland interstadials gis 25 to 19

magnetostratigraphy of chinese loess paleosol sequences abstract as one of the longest and most continuously deposited terrestrial sedimentary archives in the world chinese loess paleosol sequences record paleoclimatic and paleomagnetic variations at a range of time scales magnetostratigraphic studies provide a first order chronological framework for chinese loess sequences in this review we highlight recent developments in loess magnetostratigraphy including pedostratigraphy based on magnetic susceptibility variations we highlight progress in understanding the mechanisms by which the natural remanent magnetization nrm is acquired and discuss in detail the fidelity of paleomagnetic recording in loess records including the recording of magnetic polarity reversals excursions and relative paleointensity variations finally we discuss future prospects for studies of loess nrm

rapid and cyclic aeolian deposition during the last glacial in european loess a high resolution record from nussloch germany abstract this paper reports the results of an investigation of the weichselian upper pleniglacial loess sequences of nussloch rhine valley germany based on stratigraphy palaeopedology sedimentology palynology malacology and geochemistry 13 c supported by radiocarbon tl and osl dating grain size and magnetic susceptibility records are taken at 5 cm intervals from the upper pleniglacial upg loess the data indicate cyclic variations in loess deposition between ca 34 and 17 ka when the sedimentation rate is especially high 1 0 1 2 m per ka for more than 10 m the grain size index gsi ratio of coarse silt versus fine silt and clay shows variations which are assumed to be an indirect measurement of wind intensity the sedimentation rate interpreted from the profiles indicates high values in loess loess events le 1 to le 7 and low or negligible values in tundra gley horizons g1 to g8 osl ages from the loess and 14 c dates from organic matter in the loess show that loess deposition was rapid but was interrupted by shorter periods of reduced aeolian sedimentation comparison between the data from nussloch and other european sequences demonstrates a progressive coarsening of the loess deposits between ca 30 and 22 ka this coarsening trend ends with a short but major grain size decrease and is followed by an increase to a new maximum at 20 2 ka w shape correlation between the loess gsi and the greenland ice core dust records suggests a global connection between north atlantic and western european global atmospheric circulation and wind regimes in addition the typical upper pleniglacial loess deposition begins at ca 30 31 ka close to heinrich event he 3 and the main period of loess sedimentation at about 25 2 ka is coeval to he 2 correlation of magnetic susceptibility and grain size records shows that the periods characterised by high gsi coincide with an increase in the amount of ferromagnetic minerals reworked from the rhine alluvial plain they suggest enhancement in the frequency of the storms from n nw these results are integrated within a palaeogeographical model of dust transport and deposition in western europe for the weichselian upper pleniglacial or late pleniglacial

late quaternary glacial history of the karlik range easternmost tian shan derived from 10be surface exposure and optically stimulated luminescence datings abstract the karlik range located in the easternmost part of the tian shan is a key area in reconstructing paleoclimate in central asia but few studies have been conducted to constrain the timing and extent of quaternary glaciations in its highlands we investigated the late quaternary glacial history in the turgan valley on the northern slopes of the karlik range using cosmogenic 10be surface exposure and optically stimulated luminescence osl dating techniques four major glacial events were dated to 0 79 0 59 ka little ice age lia 15 8 1 6 ka lateglacial 37 4 4 0 44 2 4 3 ka marine oxygen isotope stage mis 3 and 60 2 3 3 79 3 5 2 ka mis 4 or older with a pattern of continuously restricted glaciations after mis 4 this glacial chronology is consistent with the studies from other parts of the tian shan the overall pattern of glaciations across the tian shan suggests that change in precipitation brought by the westerlies was the primary factor influencing the timing and extent of glacial advances during the last glaciation however lower temperature of the karlik range affected by the siberian high may counteract the effect of lower precipitation to drive a relatively extensive glacial advance in the easternmost tian shan

rivers and loess the significance of long river transportation in the complex event sequence approach to loess deposit formation abstract rivers are essential for loess deposit formation river systems which relate directly to loess deposit formation include the danube and the rhine the mississippi and the missouri the thames and the medway the indus ganges and brahmaputra the dnepr don and volga the clutha mataura and rakaia new zealand rivers the yellow river rivers in south america siberian rivers flowing north the odra and the wisla between the mountains and the ice the syr darya and amu darya into the desert the contention is that rivers are not just important in major loess deposit formation they are mandatory necessary imperative obligatory essential indispensable requisite for a complete and satisfactory study of a loess deposit we need to know how the material is produced how it is transported and distributed across the landscape how intermediate deposits are formed how transportation provides the defining properties i e open structure collapsibility draping across the landscape and what may happen post deposition e g chernozemisation fragipan formation increased collapsibility etc if rivers are essential then it would appear that the british loess is probably alpine material delivered by the proto rhine and the polish loess is not derived from the ice sheet to the north but from the mountains to the south the lack of loess in canada is explained by the absence of suitable rivers the loess in russia and neighbouring countries can be classified as jefferson et al jefferson i f evstatiev d karastenev d mavlyanova n g smalley i j 2003b the engineering geology of loess and loess like deposits a commentary on the russian literature engineering geology 68 333 351 suggested on the basis of associated rivers a new deposit of glacial loess is recognised associated with the dnepr don and volga rivers the uswr loess the smalley leach smalley i j leach j a 1978 the origin and distribution of the loess in the danube basin and associated regions of east central europe a review sedimentary geology 21 1 26 available from www geo edu ro sgr mod downloads pdf smalley sedgeo 1978 pdf vision of the loess in the danube basin and east central europe is probably misconceived they assigned a great significance to glacial action and put loess in a northern band it appears that this proposed glacial influence is minimal and that the danube loess is essentially mountain loess derived from the alps the carpathians the sudeten mountains and other high regions the danube system is a classic example of a river controlling loess distribution

pronounced changes in paleo wind direction and dust sources during mis3b recorded in the tacheng loess northwest china abstract central asia loess deposits can yield detailed records of aridification across the asian interior as well as the atmospheric circulation in this study we presented grain size heavy mineral assemblage rock magnetism and anisotropy of magnetic susceptibility of a loess section in the tacheng basin in xinjiang region nw china the results of anisotropy of magnetic susceptibility indicated that a near surface se wind prevailed in the tacheng area since marine isotope stage mis 3 while a near surface sw prevailing wind developed during mis3b we inferred that the change of wind direction was due to glacial advance during mis3b combining the result of anisotropy of magnetic susceptibility with grain size heavy mineral assemblage data and previously published low field mass susceptibility revealed that dust transported by the near surface sw wind had a greater ability to enhance magnetic susceptibility and higher amphibole epidote ratio additionally a strong siberian high during heinrich event h 5 at ca 48 ka blocked the advection of moisture into the region via mid latitude westerlies causing glacial recession and the weakening of the prevailing sw wind our study has implications for identifying changes in paleo wind direction and dust source which can aid understanding of the influence of westerlies and the siberian high on dust accumulation as well as their interactions

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

reconstructing palaeoenvironments on desert margins new perspectives from eurasian loess and australian dry lake shorelines abstract desert margins preserve evidence of more extensive arid conditions in the past and represent global hot spots with respect to climate change the balance of scientific evidence now suggests that dryland landscape reactivation did not correspond simply to ice age aridity peaks as previously assumed this paper provides a new perspective on and more nuanced understanding of desert marginal landscapes as palaeoenvironmental archives the two case studies represent ends of a sediment availability spectrum both environments experience substantial spatial and temporal variability in deposition with implications for reconstructing past environments at individual sites recently generated chronostratigraphic data from the dry subhumid dobrogea loess romania are synthesised to provide quantitative insights into the spatial and temporal organisation of loess plateaux loess accumulation peaks during the lgm and mis4 but not at all sites accumulation rates vary substantially between sites comparison of geographical context yields no clear driving mechanism for this variability secondly two transverse lunette dunes in semi arid willandra lakes australia yield comparable chronostratigraphies and distribution of stratigraphic units a first attempt is made to identify changes in wind regime through time on the australian desert margins and suggests that high latitude climate forcing may have acted upon semi arid australia over millennial scales the novel perspectives generated from the new datasets provide unprecedented insights into past climate circulation and land surface processes along desert margins these new perspectives coupled with the new geochronological and quantitative palaeoclimate proxy tools now available represent the next frontier for palaeoenvironmental research on desert margins

reevaluation of late pleistocene loess profiles at remizovka kazakhstan indicates the significance of topography in evaluating terrestrial paleoclimate records we report on a loess paleosol sequence lps near remizovka located in the northern tian shan piedmont of southeastern kazakhstan this site represents a key record for late pleistocene climatic fluctuations at the intersection of major northern hemisphere climate subsystems this paper develops a synthesized dataset of previous conflicting studies at remizovka by characterizing their paleo topographic context which had remained previously overlooked digital elevation models satellite images and archival photography characterize recent topographic developments two well developed pedocomplexes which we investigate in detail and date by luminescence mark the paleotopography during marine oxygen isotope stage mis 5 peak dust accumulation rates here occurred during the middle mis 5 and mis 4 early mis 3 these are partially comparable with records from neighboring regions but not in phase with global ice volume records this discrepancy may be related to a distinct regional environmental response to larger scale climatic drivers and local topographic influences on dust deposition patterns our findings confirm the potential of the lps remizovka to provide high resolution paleoclimate data for the late pleistocene the three dimensional stratigraphic reconstruction reinforces the caution required to correctly interpret loess formation processes prior to their interpretation as paleoclimate archives and provides guidelines for a more suitable approach

advance retreat history of the east asian summer monsoon rainfall belt over northern china during the last two glacial interglacial cycles abstract in northern china the history of desert migration provides a good measure of the east asian summer monsoon variations since the desert margin environment is very sensitive to changes in summer monsoon rainfall desert margin migration can be well documented in the downwind loess deposits since the grain size of chinese loess is principally controlled by source to sink distance and hence the loess grain size is an effective proxy for reconstructing the history of the east asian summer monsoon in order to investigate the pattern and migration of the summer monsoon rainfall belt over northern china during the past two glacial interglacial cycles contour maps of loess grain size were constructed for mis 2 3 4 5 6 and 7 all the grain size isolines show a near north south gradient for both glacials and interglacials indicating a dominant dust source region in north and an approximately north south dust transport pathway for dust deposits in the main body of the loess plateau at least for the past two glacial interglacial cycles the reconstructed southeast desert margin for mis 2 3 4 5 6 and 7 roughly parallels the present isohyets implying that the pattern of the east asian summer monsoon rainfall belt during the past two glacial interglacial cycles is similar to the present i e a northeast southwest trend for the isohyets of the summer monsoon despite the glacial interglacial cycles using the grain size isolines of mis 2 as a reference we derive a northerly desert retreat of 160 km 19 km 225 km and 223 km for mis 3 4 5 and 7 respectively and a southerly desert advance of 29 km for mis 6 that could be preliminarily regarded as the relative migration distance for the east asian summer monsoon rainfall belt in addition the inferred climate conditions in mis 3 are cool and humid in northern china while the driest and coldest interval of the last two glacial periods occurs in mis 6

grain size of loess palaeosol and red clay deposits on the chinese loess plateau significance for understanding pedogenic alteration and palaeomonsoon evolution abstract to assess pedogenic modification to grain size distributions of loess palaeosol and red clay deposits on the chinese loess plateau and to understand long term evolution of the east asian palaeomonsoon since the late miocene we investigate a continuous loess palaeosol red clay sequence at lingtai south chinese loess plateau and another parallel red clay sequence at zhaojiachuan central chinese loess plateau by analyzing the grain size distributions of bulk samples and chemically isolated quartz samples the relative intensity of pedogenic alteration of the loess palaeosol and red clay deposits can be quantified comparisons of the grain size distributions and contents of different grain size fractions between the bulk and the quartz samples suggest that pedogenic alteration is apparently stronger in the red clay sequence than in the overlying loess palaeosol deposits furthermore grain size parameters derived from the bulk and the quartz samples such as mean grain size coarse fraction content and u ratio exhibit similar variations in the loess palaeosol sequence quaternary 0 2 6 ma whereas these grain size parameters of quartz samples show different variability from those of bulk samples in the red clay sequence late miocene to pliocene 2 6 7 ma grain size of quartz from the loess palaeosol and red clay deposits exhibits distinct and persistent oscillations from the late miocene to the pleistocene implying that significant fluctuations of the palaeomonsoon climate in east asia might have occurred at least since late miocene time

loess depositional dynamics and paleoclimatic changes in the yili basin central asia over the past 250 ka abstract widely distributed loess deposits within the tianshan mountains are important archives for studying late quaternary climate in this central asian region however insufficient age control for these regional loess records especially over glacial interglacial cycles severely limits our understanding of loess depositional dynamics and accurate interpretation of paleoclimate conditions across central asia in this study we applied k feldspar optical dating and magnetic susceptibility grain size distribution caco3 and color to loess paleosol sections in the yili basin of the tianshan mountains to constrain loess depositional dynamics identify timing of loess paleosol formation and clarify the role of paleoclimate influence in this region since the late middle pleistocene our results demonstrate that loess deposition started as early as 350 ka in the yili basin following river down cutting associated with glacial interglacial transitions and exposure of riverbed sediments enhanced dust emission from flood plains played an important role in loess deposition very rapid loess deposition as high as 60 120 g cm 2 ka 1 on river terraces occurred during the last interglacial when loess accumulation at different locations of the site had remarkably different rates ranging from 10 to 100 g cm 2 ka 1 this heterogeneous behavior indicates that not only climatic changes influenced yili basin loess deposition and preservation but by complex interaction of local geomorphology wind velocity and changes of materials in dust origins depositional hiatuses frequently occurred during the past 250 ka likely induced by strong erosion resulting from increased wind strength and dry cold climate with poor vegetation cover in the region magnetic susceptibility grain size distribution caco3 and color analyses of the loess paleosol sequences showed that paleosols formed around 288 ka 230 191 ka 120 106 ka 92 89 ka and 84 71 ka hence a generally moist climate characterized the yili basin before marine isotope stages mis 9 mis 7 mis 5d mis 5b and the mis 5 mis 4 transition respectively this study suggests a climate pattern of moist interglacial and dry glacial periods in the tianshan mountains whereas substages of interglacials had cold moist and warm dry climate characteristics

a late pleistocene holocene lacustrine record from lake manas zunggar northern xinjiang western china information on the late quaternary palaeoclimate in the zunggar desert northern xinjiang is deduced from the study of three 5 m long cores taken from lake manas analyses including the mineralogical composition of bulk sediments stable isotope contents of carbonates organic matter pollen and diatoms were performed to help reconstruct the environmental evolution of the area the chronology is provided by 9 ams 14c dates done on carbonates or organic matter the record suggests a late pleistocene humid episode radiocarbon dated at 37 000 32 000 yr b p this episode is followed by a period of extreme aridity attributed to the last glacial maximum the early mid holocene record indicates conditions generally wetter than today as previously established for western china however our results show that the holocene period is rather complex after a minor wet warm pulse estimated to be around 12 000 yr b p the most important environmental change is recorded at 10 000 yr b p it led to the establishment of a steppic vegetation cover in the catchment and of a permanent lake which lasted 4000 years fluvial sedimentation took place between about 6000 and 4500 yr b p and it coincided with a decrease in moisture availability for vegetation growth a second lacustrine episode is recorded from about 4500 to 2500 yr b p although the pollen record and a sudden influx in detrital organic matter suggest a short term dry event around 3800 3500 yr b p the last 2500 years show climate unstability and the step wise establishment of hypersaline conditions in lake manas the major post glacial environmental changes appear to be roughly in phase with those observed in tibet

the provenance of taklamakan desert sand sand migration in the vast taklamakan desert within the tarim basin xinjiang uyghur autonomous region pr china is governed by two competing transport agents wind and water which work in diametrically opposed directions net aeolian transport is from northeast to south while fluvial transport occurs from the south to the north and then west to east at the northern rim due to a gradual northward slope of the underlying topography we here present the first comprehensive provenance study of taklamakan desert sand with the aim to characterise the interplay of these two transport mechanisms and their roles in the formation of the sand sea and to consider the potential of the tarim basin as a contributing source to the chinese loess plateau clp our dataset comprises 39 aeolian and fluvial samples which were characterised by detrital zircon u pb geochronology heavy mineral and bulk petrography analyses although the inter sample differences of all three datasets are subtle a multivariate statistical analysis using multidimensional scaling mds clearly shows that tarim desert sand is most similar in composition to rivers draining the kunlun shan south and the pamirs west and is distinctly different from sediment sources in the tian shan north a small set of samples from the junggar basin north of the tian shan yields different detrital compositions and age spectra than anywhere in the tarim basin indicating that aeolian sediment exchange between the two basins is minimal although river transport dominates delivery of sand into the tarim basin wind remobilises and reworks the sediment in the central sand sea characteristic signatures of main rivers can be traced from entrance into the basin to the terminus of the tarim river and those crossing the desert from the south to north can seasonally bypass sediment through the sand sea smaller ephemeral rivers from the kunlun shan end in the desert and discharge their sediment there both river run off and wind intensity are strongly seasonal their respective transport strength and opposing directions maintain the taklamakan in its position and topography

vegetation and climate history in arid western china during mis2 new insights from pollen and grain size data of the balikun lake eastern tien shan marine isotope stage mis 2 is mostly a cold period encompassing the last glacial maximum lgm but the regional expression of mis2 in arid areas of china is not well known in this paper we use high resolution lacustrine pollen and grain size records from balikun lake to infer vegetation lake evolution and climate in arid western china during mis2 our results suggest that 1 the regional vegetation around balikun was mainly dominated by desert and or desert steppe and balikun lake was relatively shallow and experienced high aeolian input during mis2 2 distinctive runoff from mountain glacial meltwater in the eastern parts of the balikun basin caused a high relative abundance of artemisia pollen during the lgm 26 5 19 2 cal kyr bp while simultaneously the desert areas expanded as indicated by the high abundance of desert shrubs e g elaeagnaceae rhamnaceae hippophae this cold and dry lgm climate triggered a substantial lowering of lake level 3 an extremely cold and dry climate prevailing from 17 0 to 15 2 cal kyr bp correlated with heinrich event 1 h1 would explain the low vegetation cover found then and 4 the warm and humid bolling allered interstadial ba ca 15 ca 13 cal kyr bp is clearly recorded in the balikun region by the development of wetland herb communities e g poaceae cyperaceae typha and the lake level rose due to increased runoff our results challenge the traditional view of cold and wet climatic conditions and high lake levels in arid western china during the lgm and we propose that changes in local temperature modulated by july insolation was an indispensable factor in triggering vegetation evolution in the balikun region during mis2 c 2015 elsevier ltd all rights reserved

geomorphological and sedimentological precautions in radiocarbon dating of eolian and lacustrine sequences in arid asia abstract lacustrine sediments in deep lakes are suitable for establishing radiocarbon chronology lacustrine sediments in shallow lakes are not suitable for establishing radiocarbon chronology simply because younger plant roots can readily penetrate into older lacustrine sediments three features are warning signs for shallow lake sediments 1 high concentration of salts 2 abundant vertically oriented plant residues and 3 organic matter enriched sand layer field and laboratory investigations of eolian and water reworked eolian sequences suggest that fluvial addition and fluvial alteration on terraces may produce reversed chronologies fluvial layers interbedded within eolian sequences should be avoided in obtaining dating targets and eolian layers isolated by fluvial or lacustrine layers should be the targeting layers from which dating samples should be obtained bulk sediment 14 c dates of a paleosol at yuanbao loess section in the western chinese loess plateau are distinctively older than charcoal dates suggesting that bulk sediment samples contain older organic carbon that was likely brought upward by animal burrowing in contrast bulk sediment dates were found to be systematically younger than snail and charcoal dates at the romantic section in eastern kazakhstan the younger dates likely resulted from the downward intrusion of plant roots and or translocation of mobile organic compounds into deeper layers the only suggestion is to avoid bulk sediments as dating targets in eolian paleosol sequences the misleading chronology for the upper loess paleosol complex at lujiagou section indicated that even continuous loess deposits may yield reversed chronologies where loess has inherited older organic carbon from deflated floodplains and from loess hills all kinds of dating targets including charcoals may produce unreliable chronologies

making the material the formation of silt sized primary mineral particles for loess deposits abstract in 1911 e e free wrote it may be well to point out that there are really two problems of the loess a problem of the origin of material and a problem of deposition the problem of the origin of material has been relatively neglected in comparison to problems of deposition of the formation of deposits and latterly in comparison to studies of loess stratigraphy if we are to understand the true nature of loess this fascinating material we need to be aware of all the significant events in the processing of the particles which form a deposit a large amount of silt sized primary mineral material has to be produced to make a loess deposit loess is a quaternary phenomenon and we see the entire process being completed in quaternary times some powerful quaternary forces are able to produce very large amounts of granular material glacial grinding vigorously supported by smalley 1966a provides an obvious source for some loess material but the vast deposits of north china and central asia have no obvious glacial connection however they are adjacent to high asia a region of vast tectonic activity and an enormous release of terrestrial energy in the last several million years high asia is a large producer of loess silt much of which finds its way south to make the ganges delta but large amounts are moved north and east to make huge loess deposits africa presents a problem recent work e g coude gaussen 1987 suggests that there is a region of peri saharan loess but earlier observations e g penck indicate quite clearly that the sahara region is free of loess rathjens 1928 in his study of tripolitania indicated the presence of loess like deposits and described their nature but he did point out that 90 of the granular material was greater than 100 pm in diameter which would remove it from a strict loess definition on the soil taxonomy map of africa there is a belt of soil d3 which could include considerable loess deposits it stretches from the matmata loess in tunisia across northern libya to the western part of the egyptian coastal region if d3 contains loess this points to a genuine desert loess particle producing mechanism operating in the sahara

the agh band loess palaeosol sequence a terrestrial archive for climatic shifts during the last and penultimate glacial interglacial cycles in a semiarid region in northern iran abstract the northern iranian loess profiles host important information on quaternary climate and palaeoenvironmental changes in the region they build an important link between the eurasian loess belt and european and central asian archives due to a climatic gradient with decreasing precipitation from the west to the east and from the south to the north loess palaeosol sequences formed synchronously under different climatic conditions can be studied over short distance in the iranian caspian lowland the agh band profile is located in the so called iranian loess plateau a semi arid region with 200 350 mm annual precipitation the loess deposits at agh band reach a thickness of 60 m an about 50 m thick step profile was prepared and the litho pedostratigraphy was investigated samples for laser diffractometry grain size measurements were taken every 2 cm the magnetic susceptibility was measured in 4 cm intervals and the caco3 content in 8 cm intervals to establish a chronological framework a pirir290 luminescence dating approach was applied to the 4 11 m polymineral fraction the results show that the agh band profile yields a climate archive reaching from mis 7 to mis 2 several chronological hiatuses of some 10 ka show that periods of intense loess accumulation were interrupted by phases of only minor loess sedimentation and or erosion the agh band profile is subdivided by several shifts in grain size distribution the coarsening and fining up trends correlate with increasing and decreasing wind velocity respectively in the central part of the agh band loess sequence a weakly developed palaeosol is preserved which was developed at around 80 ka furthermore the loess deposits formed from about 100 ka to 60 ka ago show banded structures a pedocomplex including two well developed palaeosols consisting of bw y horizons and a cb horizon as well as intercalated loess can be found in the lower part of the sequence also evidenced by the increased values of magnetic susceptibility the corresponding luminescence age estimates indicate that the palaeosols represent a period of increased humidity and landscape stability during late mis 7 and mis 6 hence in the agh band loess various changes in the palaeo sedimentary system triggered by changes in climate can be observed this yields important information on the sensitive response of sedimentary systems and landscapes within semi arid regions to shifts in moisture and possibly temperature

late glacial lake level changes in the lake karakul basin a closed glacierized basin eastern pamirs tajikistan abstract the lake level variations during the late glacial in the lake karakul basin a closed glacierized basin in the northernmost part of the eastern pamirs were reconstructed using geomorphological and sedimentological evidence with a chronology developed using luminescence ages from sand sized quartz and k feldspar in the lake sediments lake transgression started before 19 ka with the peak water level of 35 m above the present elevation occurring at 15 ka this was synchronous with a significant advance of the glacier in the catchment stepwise lake regression including a rapid lowering of the lake level 13 m at 12 ka persisted until at least 10 ka lake transgression and localized glacier expansion from 19 to 15 ka likely correlate with the more regional late glacial glacier advances across the semi arid western himalayan tibetan orogen and the eastern pamirs the longer term trend of this lake transgression was probably caused by colder and or wetter climatic conditions forcing a notable glacier advance

impacts of uplift of northern tibetan plateau and formation of asian inland deserts on regional climate and environment abstract based on the geological evidence that the northern tibetan plateau ntp had an uplift of a finite magnitude since the miocene and the major asian inland deserts formed in the early pliocene a regional climate model regcm4 1 with a horizontal resolution of 50 km was used to explore the effects of the ntp uplift and the related aridification of inland asia on regional climate we designed three numerical experiments including the control experiment representing the present day condition the high mountain experiment representing the early pliocene condition with uplifted ntp but absence of the asian inland deserts and the low mountain experiment representing the mid miocene condition with reduced topography in the ntp by as much as 2400 m and also absence of the deserts our simulation results indicated that the ntp uplift caused significant reductions in annual precipitation in a broad region of inland asia north of the tibetan plateau tp mainly due to the enhanced rain shadow effect of the mountains and changes in the regional circulations however four mountainous regions located in the uplift showed significant increases in precipitation stretching from the pamir plateau in the west to the qilian mountains in the east these mountainous areas also experienced different changes in the rainfall seasonality with the greatest increases occurring during the respective rainy seasons predominantly resulted from the enhanced orographically forced upwind ascents the appearance of the major deserts in the inland asia further reduced precipitation in the region and led to increased dust emission and deposition fluxes while the spatial patterns of dust deposition were also changed not only in the regions of uplift impacted topography but also in the downwind regions one major contribution from this study is the comparison of the simulation results with 11 existing geological records representing the moisture conditions from miocene to pliocene the comparisons revealed good matches between the simulation results and the published geological records therefore we conclude that the ntp uplift and the related formation of the major deserts played a controlling role in the evolution of regional climatic conditions in a broad region in inland asia since the miocene

origin of loess deposits in the north tian shan piedmont central asia abstract loess deposits are widely distributed along the mountain piedmonts of central asia the transport processes and origins of central asian loess sediments remain poorly understood here we investigate the origin and formation of loess along the northern piedmont of the tian shan based on trace element including rare earth element ratios and multidimensional scaling analysis our results indicate that the loess has undergone weak chemical weathering using a selection of geochemical fingerprinting techniques based on pearson correlation and kruskal wallis h tests we establish a genetic link between alluvial proluvial fans plains deserts and loess along the tian shan piedmont in northern kyrgyzstan and southern kazakhstan the unsorted sediments on the piedmont slopes and alluvial proluvial plains are common sources for both deserts and loess to the north of the tian shan dune sediments are not the main source of the fine grained loess origin and formation of central asian loess is strongly dependent on local topographic context and wind dynamics only once loess provenance and formation has been understood across both space and time can reliable interpretations of palaeoclimatic proxies in these deposits be made

ubiquity of anomalous fading in k feldspars and the measurement and correction for it in optical dating anomalous fading rates were measured in k feldspars separated from 49 sediment samples mainly from north america the intensity of the optically stimulated luminescence was found to decrease linea

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

differential ice volume and orbital modulation of quaternary moisture patterns between central and east asia abstract desertification is of pressing environmental concern in large parts of asia and directly affects millions of people arid central asia aca in particular is highly sensitive to desertification and environmental change climate change in aca may be driven by westerly circulation or monsoon variation however no consensus exists over their relative importance during the quaternary and this greatly restricts our understanding of how this region may be affected by future climate change here we use the most detailed luminescence dating age model yet produced for aca for three loess records in the tianshan mountains spanning the past 250 ka to show a sharp dichotomy in moisture variation between lowland and high mountain areas the lowland areas of aca are subjected to persistent aridity during past 250 ka while highland areas clearly show dry glacial and moist interglacial changes synchronous to moisture variability in monsoonal east asia and both co varying with global ice volume and greenhouse gas ghg variation in contrast moisture variability across aca within interglacials varies inversely with insolation driven precessional changes this is directly out of phase with the moisture changes of east asia which co vary with precessional insolation changes and indicates the influence of westerly circulation in aca our flexible global ocean atmosphere land system model simulations further reveal that coupled ice volume and ghg variations dominated climatic variability in both aca and east asia over glacial interglacial cycles however the out of phase relationship between the intensity of the westerly and east asian monsoon systems during interglacial periods indicates that precessional forcing is responsible for differences in moisture patterns between aca and east asia these observations indicate that moisture levels will not increase even in high altitude regions of aca over the next several millennia rather desertification is likely to worsen resulting from stabilization of the westerlies as a result of low summer insolation

austrian mis 3 2 loess palaeosol records key sites along a west east transect based on a w e transect through the northern loess regions of austria palaeoenvironmental studies were carried out in three loess palaeosol sequences gunderding krems wachtberg and stillfried b locus typicus to complement available results in the context of a multi methodological approach on the base of previously published datings our study concentrates on the mis 3 2 transition the results of detailed micromorphological investigations prove that palaeopedogenesis frost processes and sedimentation rates differ in their spatial occurrence in the loess belt of austria all three sequences are in line with the general trend of a reduced intensity of pedogenic and cryogenic features from western to south eastern europe which can be explained by lower atlantic moisture influence towards the east interstadial cambic horizons are well developed in the mis 3 sequence of western austria whereas the eastern loess profiles only show weak pedogenesis in all studied sequences frost processes were active during the upper mis 3 and mis 2 the studied mis 2 records are characterised by tundra soils with reductaquic horizons which is a clear sign for prolonged phases of permafrost on the spatial scale the sedimentation rate increases in the eastern loess regions and particularly the krems wachtberg sequence in the centre of the transect experienced an exceptionally high sedimentation rate and can thus be seen as one of the most important high resolution records for the mis 3 2 transition in european loess regions

loess genesis and worldwide distribution abstract loess formation generally involves the four main stages of production deflation transportation and deposition of loess particles traditionally loesses are classified as glacial desert or other types based only on source area characteristics without taking into account provenance and transportation research on loess genesis is often local with only a few attempts at systematically overviewing worldwide loess distribution both the local and few global studies lack information on the variability in loess thickness continuity and areal extent this review integrates a large body of information on loess source areas and transportation pathways and the existence of desert transition zones three modes of loess genesis 1 continental glacier provenance river transport 2 mountain provenance river transport and 3 mountain provenance river transport desert transition were identified global distribution maps of provenance and transport pathways of major loess areas and their different genesis modes were meticulously prepared maps showing the spatial distribution thickness and continuity of loess deposits were also composed and the sizes of loess covered areas of each continent were re estimated the main features related to the distribution of the loess deposits on each continent are summarized for different regions or as a whole depending on the coverage of the source maps and references

a joined rock magnetic and colorimetric perspective on the late pleistocene climate of orlovat loess site northern serbia abstract this study represents the first detailed joined colorimetric and rock magnetic investigation on a loess paleosol sequence in the vojvodina region northern serbia the aim of this paper is to derive new information on the late pleistocene paleoenvironment from a high resolution multi proxy assessment of the iron mineralogical composition at the orlovat loess paleosol sequence the orlovat section is the first site from the banat loess region analyzed for quaternary paleoclimate information and accordingly it is the easternmost loess section in the serbian loess region studied in contrast to other serbian sites the orlovat site is not located in a plateau rock magnetic analysis and the luminescence dating based chronology revealed active slope processes at this site during the late pleistocene this is the most strikingly evidenced by the absence of a middle wurmian mis 3 interstadial pedocomplex present as marker horizon in the serbian plateau loess sites nevertheless important stratigraphic units and distinct pattern of the proxy records can be correlated to other key sites of the vojvodina loess region hence this section provides an opportunity to reconstruct local as well as regional environmental and climatic conditions during the late pleistocene the applied multiproxy approach especially allowed valuable insight in the environmental conditions that prevailed during formation of the last interglacial pedocomplex accordingly in the eemian pronounced summer dryness prevailed during the formation of the eemian soil the dry period was warmer and lasted longer or was characterized by less precipitation as during formation of the modern soil although the soil moisture deficit in the eemian summers was most likely higher the rainfall was more pronounced in the period of from spring to early summer and or autumn as during the holocene these findings support previous observations from the batajnica site a key site of the vojvodina loess region and highlight the eemian as potential past analogue to future climate warming in serbia this study points out the potential of a joined colorimetric or spectrometric analyses and rock magnetic analyses in paleoenvironmental investigations on loess paleosol sequences

stratigraphies and chronologies of late quaternary loess paleosol sequences in the core area of the central asian arid zone abstract the sporadic distribution of the quaternary loess in central asia makes it hard to establish a regional pedostratigraphy through visual tracing of marker strata the pedostratigraphic correlation presented here is thus completely based on the radiocarbon chronologies of the four studied sections the first noticeable feature is that poorly drained conditions predominated in the period between 48 000 and 30 000 14 c bp during which three entisols developed at 45 000 14 c bp 40 000 14 c bp and 35 000 14 c bp after a period of loess deposition between 30 000 and 18 000 14 c bp under poorly drained conditions an entisol at the westernmost site valikhanov south central kazakhstan developed between 18 000 and 10 000 14 c bp also under poorly drained conditions the time equivalent deposits at romantic and zeketai sections to the east do not exhibit any soil forming characteristics although poorly drained conditions are also imprinted in the time equivalent loess the holocene sequences in the central asian domain consist of an early holocene loess unit deposited between 10 000 and 5 000 14 c bp and a late holocene soil formed during the past 5000 years in comparison the climate was also wet between 48 000 and 20 000 14 c bp during which three mollisols developed under well drained conditions in the chinese loess plateau of the east asian domain the loess deposited between 23 000 and 10 000 14 c bp in the chinese loess plateau has neither observable marks of soil formation nor imprints of poorly drained conditions the holocene sequence in the east asian domain exhibits an out of phase relationship with that in the central asian domain consisting of an early holocene soil formed between 9000 and 4000 14 c bp and a late holocene loess unit deposited during the past 4000 years

pleistocene environmental dynamics recorded in the loess of the middle and lower danube basin abstract the substantial loess deposits of the middle and lower danube basin in southeastern europe represent one of the thickest and most comprehensive terrestrial palaeoenvironmental records on the continent yet are also the least well understood environmental conditions over the last million years have resulted in relatively continuous deposits uninterrupted by glaciation and tundra conditions which nevertheless reflect oscillations between relatively warm humid interglacial and cold dry glacial intervals this relative environmental stability may have proven important for hominins migrating into and through the region the loess stratigraphy comprises distinct loess paleosol sequences reflecting glacial interglacial phases which can be quantified for intensity using environmental magnetism and geochemistry these phases are emphasised by variations in vegetation and malacofauna which respond to climatic change the loess deposits demonstrate broadly similar sedimentological characteristics across the basin danubian loess deposits initiated in response to the tectonic formation of the pannonian basin retreat of the large palaeolakes and increased sediment supply from the danube the period from 1 ma 500 ka mis 27 13 was characterised by alternating loess deposition and pedogenesis during glacial and interglacial periods respectively in response to relatively humid forested conditions this period represents the opening of the danube corridor and provides the backdrop for initial hominin arrival into europe after 500 ka and particularly after mis 9 loess accumulation rates increased in response to relatively more steppic arid environments mis 9 and 13 15 were the most humid phases of the last 600 ky the mis 5 interglacial period was the warmest and relatively most humid period preceding the holocene and was followed by substantially increased loess accumulation during mis 4 which may be linked to north atlantic circulation the complexity of the mis 3 interstadial paleosol suggests that conditions were not uniformly warm and wet during this time mis 3 corresponds with the first arrival of anatomically modern humans to europe the last glacial maximum and younger dryas of mis 2 were characterised by substantially increased loess accumulation indicating cold steppe environments most likely influenced by the north atlantic although conditions were sufficiently mild that the region acted as a refugium for thermophilic biota as may also have been the case for most of the pleistocene glacial cycles the holocene soil represents relatively wamer and more humid conditions corresponding to the current interglacial

the loess sequence from remisowka northern boundary of the tien shan mountains kazakhstan part i luminescence dating abstract similar to the chinese loess the loess deposits surrounding the high mountain regions of central asia play an important role in understanding the climate and environmental change during the pleistocene in eurasia despite their thickness and widespread distribution the loess deposits in southeast kazakhstan have so far not been investigated in detail the remisowka loess palaeosol sequence is located in the vicinity of the north tien shan mountains at an altitude of 1070 m above sea level in the profile under study nine loess layers were distinguished intercalated by eight pedocomplexes and so indicating a similar cyclicity like the loess palaeosol sequences in central asia and china at the remisowka section 12 loess samples were taken to set up a more reliable chronological model for the section using a luminescence dating approach polymineral fine grains were investigated by infrared optically stimulated luminescence applying the multiple aliquot additive dose protocol preliminary fading experiments were carried out for one sample taken from the uppermost loess layer while the results of the uppermost layer are in agreement with geological age estimates and indicate a correlation to the late glacial age underestimation is very likely for the samples below the first weak palaeosol no significant age increase with depth was recognised the reason for this age underestimation is not yet fully understood but could be related to anomalous fading further methodological approaches are necessary as well as a combination of different chronometric techniques for improvement of the results

investigating the last glacial gravettian site sagvar lyukas hill hungary and its paleoenvironmental and geochronological context using a multi proxy approach abstract gravettian population during the last glacial maximum lgm was sparse in europe this is generally related to harsh environmental conditions here we report of geoarcheological investigations physical chemical and biological data of the sagvar site in the hungarian part of the carpathian basin in southeastern europe geochronological control is given by luminescence dating which places loess accumulation between 20 6 1 4 ka and 17 7 1 2 ka this study demonstrates that human occupation at sagvar did not occur during a rather mild climatic phase but during a typical cold lgm climate of the two cultural layers discussed at the section the upper one can be clearly distinguished in the section by the physical proxy data while the lower one is observed only in some proxies similarly previous archeological investigations describe a higher tool density in the upper layer the mollusk composition indicates dry climate for both occupation phases but the paleoecology of the lower occupation phase suggests also the presence of mosaic spots of wet tundra which allowed for increased weathering processes in the sediment these are preserved as indications for weak pedogenesis in the physical and chemical proxy data although a disturbance of human occupation in the signal cannot be excluded this study demonstrates the advantages of integrating proxy data of different disciplines

tien shan geohazards database earthquakes and landslides abstract in this paper we present new and review already existing landslide and earthquake data for a large part of the tien shan central asia for the same area only partial databases for sub regions have been presented previously they were compiled and new data were added to fill the gaps between the databases major new inputs are products of the central asia seismic risk initiative casri a tentative digital map of active faults even with indication of characteristic or possible maximum magnitude and the earthquake catalogue of central asia until 2009 that was now updated with usgs data to may 2014 the new compiled landslide inventory contains existing records of 1600 previously mapped mass movements and more than 1800 new landslide data considering presently available seismo tectonic and landslide data a target region of 1200 km e w by 600 km n s was defined for the production of more or less continuous geohazards information this target region includes the entire kyrgyz tien shan the south western tien shan in tajikistan the fergana basin kyrgyzstan tajikistan and uzbekistan as well as the western part in uzbekistan the north easternmost part in kazakhstan and a small part of the eastern chinese tien shan for the zones outside kyrgyzstan and tajikistan only limited information was available and compiled on the basis of the new landslide inventory and the updated earthquake catalogue the link between landslide and earthquake activity is analysed first size frequency relationships are studied for both types of geohazards in terms of gutenberg richter law for the earthquakes and in terms of probability density function for the landslides for several regions and major earthquake events case histories are presented to outline further the close connection between earthquake and landslide hazards in the tien shan from this study we concluded first that a major hazard component is still now insufficiently known for both types of geohazards and even totally unknown for most giant landslides the time information thus dating rockslides and any large mass movement is a crucial factor in order to better constrain related hazards second we highlight the role of coupled hazards in the tien shan inside the mountain range the largest disasters were caused by earthquake triggered landslides and massive earth flows therefore it is of prime importance for these mountain regions to complement single hazard assessment by coupled hazard scenarios on the basis of these scenarios risk evaluations may then be completed considering direct impacts on artificial dams hydropower schemes mining and road infrastructure as well as remote effects from possible dam breaches and mobilisation of mining and nuclear waste storages basic hazard and risk components are partly analysed in this paper and partly in a companion paper tien shan geohazards database landslide susceptibility and impacts

late pleistocene dust dynamics and pedogenesis in southern eurasia detailed insights from the loess profile toshan ne iran abstract in southern eurasia recurrent phases of aridization dust source extension and enhanced aeolian sedimentation alternated with moister intervals promoting reduced deflation areas and dust accumulation in the context of late pleistocene climate changes weathering and soil forming intensity in this greater region are hence mainly governed by fluctuations in the balance between dust supply and moisture availability among the hitherto known sections the toshan loess soil sequence lps represents a key site due to the quality of the record and the multitude of available data giving detailed insights into the timing and magnitude of dust accumulation and soil formation of the region to elucidate these dynamics for much of the past 130 000 years bulk mineralogical and geochemical data are presented supplemented by a high resolution magnetic susceptibility record and by the results of a detailed micromorphological study of loess at toshan the last interglacial luvisol phaeozem like mis 5e and the early glacial interstadial steppic palaeosols mis 5 c and a are characterized by gradually increasing grain size and decreasing degrees in decomposition of micaceous and mafic minerals pronounced feldspar weathering is detected in the last interglacial and modern soils only which formed under reduced or absent dust deposition on penultimate and last glacial loess respectively postsedimentary the overall pedosedimentary conditions correspond to large scale trends of increasing drought dust accumulation and wind strength in southern eurasia in relation to decreasing moisture availability towards the early pleniglacial mis 4 causing soil formation under ongoing dust deposition synsedimentary similar intervals of synsedimentary soil formation are recorded during the interglacial interstadial stadial transitions of the early glacial and during pleniglacial mis 4 to 2 interstadials the latter are marked by gradual increases in magnetic susceptibility colour and decreasing texture conversely silicate weathering could not be detected suggesting that grain size fluctuations are a primary feature thus windy and arid pleniglacial conditions in southern eurasia were interrupted by intermittent phases of synsedimentary soil formation in response to short lived and relatively moist interstadials although the interrelation of these incipient soils throughout southern eurasia is afflicted with considerable restrictions the oscillatory pattern of the toshan lps bears great similarity with millennial scale oscillations recorded in limnic archives of western asia

loess accumulation during the last glacial maximum evidence from urluia southeastern romania abstract the eastern european loess steppe represents one of the most substantial landform types on the continent yet the impact on this region of the last glacial maximum lgm the coldest climatic episode during the last full glacial cycle is relatively poorly understood this is in part due to the comparatively small number of sites which have been reliably dated and in part due to the need to better elucidate depositional models for loess environments at both local and regional scales here we present a high frequency age depth profile for the last 40 ky from a loess deposit at urluia in southeastern romania using fine grained quartz optically stimulated luminescence osl dating and environmental magnetism analyses loess accumulation at the site for this period is well constrained by a clearly identifiable tephra deposit corresponding to the ca 39 ka campanian ignimbrite we show that the tephra is directly overlain by a relatively thin layer of loess corresponding to marine isotope stage mis 3 which is partially overprinted by a weakly developed paleosol the sequence is dominated by a 6 8 m package of primary loess of lgm age the eight osl samples from this package group together around a mean age of 21 6 1 5 ka and suggest rapid and substantial deposition during this phase the uppermost part of the section indicates significantly reduced loess accumulation during the deglacial period into the holocene less than 2 m in total thickness the rapid accumulation of loess during the lgm at urluia is consistent with increased sedimentation at other loess profiles in the lower danube basin although the variable thickness of these deposits across the catchment highlights the need to more explicitly investigate depositional models for loess the urluia record complements emerging data which suggests that the lower danube loess steppe was cold dry and windy during the lgm yet experienced milder climates than comparable latitudes further west and north and did not undergo periglacial activity

active tectonics around almaty and along the zailisky alatau rangefront this is the author accepted manuscript the final version is available from wiley via http onlinelibrary wiley com doi 10 1002 2017tc004657 abstract

the loess record in southern tajikistan and correlation with chinese loess in the present study the chashmanigar loess soil sequence in southern tajikistan is studied this loess section has a paleomagnetic basal age of about 1 77 myr magnetic susceptibility color reflectance and grain size were systematically measured for closely spaced samples from the section paleosols consistently have a finer grain size distribution higher magnetic susceptibility redder color reflectance and lower dust sedimentation rate than loess horizons suggesting a colder drier and dustier environment during glacial periods than in interglacial periods the grain size record was tuned to variations in obliquity and precession of the earth s orbit the resulting magnetic susceptibility grain size and color reflectance time series all show well expressed astronomical periodicities during the pleistocene the mid pleistocene climate transition characterized by a shift of dominant climatic periods from 41 kyr to 100 kyr at about 1 0 0 8 myr is clearly documented in these proxy records comparison of the chashmanigar loess record with the lingtai loess section in china and the odp site 677 n 18 o record shows that during the entire pleistocene the climate cycles recorded by the central asian loess can be well correlated to the chinese loess and deep sea oxygen isotope records it is suggested that alternations of loess and soil horizons both in central asia and china could be basically forced by global ice volume variations although different wind systems have controlled the pleistocene loess transport and sedimentation in the two areas 2002 elsevier science b v all rights reserved

luminescence dating of the stratzing loess profile austria testing the potential of an elevated temperature post ir irsl protocol abstract feldspar infrared stimulated luminescence irsl signals saturate at 2000 gy i e 500 700 ka assuming a dose rate of 3 4 gy ka typical for loess and it is therefore theoretically possible to date middle pleistocene loess however the accuracy of age estimates is hampered by anomalous fading which leads to significant age underestimation fading corrections have been proposed but these corrections are reliant on inherent assumptions and in any case are inapplicable at large doses as the growth curve approaches saturation recent studies have identified a post ir irsl signal that shows less fading and is thus less dependent on accurate fading corrections this study builds upon these investigations and applies a post ir irsl sar dating protocol to polymineral fine grain samples of the loess palaeosol sequence in stratzing lower austria after a preheat at 320 c 60 s and an ir bleach at 50 c 200 s irsl was measured at 290 c for 200 s the same set of conditions were used to measure the response to a test dose recycling ratios recuperation and dose recovery tests show that this protocol is suitable for the loess under investigation although finite residual doses of up to 20 gy are observed for the oldest samples the natural signal is in or close to saturation indicating that fading is negligible in nature this observation is inconsistent with the measured laboratory fading rates of 1 1 5 decade and needs further investigation

evaluating the paleoclimatic significance of clay mineral records from a late pleistocene loess paleosol section of the ili basin central asia in this study we present clay mineral records from a late pleistocene loess paleosol sequence in the ili basin central asia and assess their significance for paleoclimatic reconstruction the results show that the clay minerals are mainly illite average 60 and chlorite 28 with minor kaolinite 9 and smectite 3 illite was of detrital origin with no obvious modification to its crystal structure increases in illite content in the loess are ascribed to wind intensity rather than pedogenesis high proportions of illite in the clay fraction and of muscovite in the bulk samples of the paleosol units may lead to an overestimation of the weathering intensity kaolinite was likely inherited from the sedimentary rocks while chlorite might have been inherited from both sedimentary and metamorphic rocks the paleoclimatic signals of kaolinite and chlorite were unclear due to reworking by both fluvial and eolian systems smectite was more likely formed by the transformation of biotite and illite and its variation in the loess sequence was also controlled by wind intensity this was largely due to aggregation and is unlikely to reflect moisture changes although the interpretation of paleoclimate evolution may contain some uncertainties clay mineralogy does provide the possibility of tracing dust provenance

dating synthesis and interpretation of palaeoclimatic records of the last glacial cycle and model data integration advances by the intimate integration of ice core marine and terrestrial records cost action es0907 since 2010 the intimate integration of ice core marine and terrestrial records network has been operating as a cost action designated es0907 this paper outlines the accomplishments of the intimate cost action in the context of how the intimate ideas have evolved during the network s twenty year life span and highlights a number of challenges that can guide further work in the second part of the paper the contributions that comprise this intimate special issue are introduced

nature and timing of quaternary glaciation in the himalayan tibetan orogen abstract much effort has been made in recent years to define the timing and extent of quaternary glaciation throughout the himalayan tibetan orogen these studies are challenging because of the logistical and political inaccessibility of the region and the inherent problems associated with the application of numerical dating techniques nevertheless the studies are providing abundant evidence for significant glacial advances throughout the last several glacial cycles and are beginning to accurately define the extent and timing of glaciation in selected regions studies are showing that himalayan tibetan glaciers in arid regions during the last glacial cycle reached their maximum extent early in the cycle and that global last glacial maximum glacier advances were significantly less extensive however along the more monsoonal influenced greater himalaya there is increasing evidence to suggest that glaciation was more extensive later in the last glacial cycle but this has yet to be fully assessed in addition the new studies are showing that throughout most himalayan tibetan regions significant glacier advances occurred during the lateglacial and early holocene with minor advances in some regions during the mid holocene the still relatively poor chronological control in the himalayan tibetan orogen however makes it difficult to construct correlations across the region and with regions elsewhere in the world this in turn makes it hard to assess the relative importance of the different climatic mechanisms that force glaciation across the himalayan tibetan orogen and to quantify paleoclimate change in this high altitude subtropical region the lateglacial and holocene glacial records however are particularly well preserved in several himalayan tibetan regions glacial successions such as these have the greatest potential to be examined in detail using newly developing numerical dating and geomorphic and sedimentologic methods to derive high resolution terrestrial records of glaciation that will help in paleoclimatic reconstruction for high altitude subtropical regions

tien shan geohazards database landslide susceptibility analysis abstract this paper is the second part of a new geohazards analysis applied to a large part of the tien shan central asia focused on landslide susceptibility computations that are based on recently compiled geographic geological and geomorphological data the core data are a digital elevation model an updated earthquake catalogue an active fault map as well as a new landslide inventory the most recently added digital data are a new simplified geological map an annual precipitation map as well as river and road network maps that were produced for the kyrgyz and tajik parts of the tien shan on the basis of these records we determine landslide densities with respect to morphological m geological g river distance r precipitation p earthquake e and fault f distance factors correlations were also established between scarp locations and the slope angle distance to rivers curvature these correlations show that scarps tend to be located on steeper slopes farther from rivers and on more convex terrain than the entire landslides on the basis of the landslide density values computed for each class of the aforementioned factors two landslide susceptibility maps are created according to the landslide factor analysis the first one considers correlations between the landslide occurrences and the first four factors mgrp the second one is based on the first map mgrp combined with the seismo tectonic influence e f on landslide distributions from the comparison of these two maps with actual landslide distributions we infer that the distances to rivers as well as to faults and past earthquakes most strongly constrain the susceptibility of slopes to landslides we highlight several zones where the landslide susceptibilities computed for the mgrp e f factors fit better the observed concentration of landslides than those computed for the mgrp factors alone for a few zones both maps produce high landslide susceptibilities that do not well reflect the observed low sub regional landslide activity for some cases we consider that some influencing factors must not have been well taken into consideration for others we show that we simply had missed landslide detections at the scale of the mountain range the computed landslide susceptibility maps fit the observed landslide distributions relatively well but these maps only represent the spatial component of landslide hazards temporal aspects are not considered by this analysis

terrestrial mollusk records in the loess sequences from eastern central asia since the last deglaciation and their paleoenvironmental significance abstract a variety of proxies has been studied to document paleoclimatic changes in arid central asia aca however biological archives which can be directly related to climatic conditions are still scarce in this region here we report records of the total count fossils tcf of terrestrial mollusks organic carbon isotopes 13corg and loss on ignition loi since the last deglaciation in the talede and xrblk loess sections in xinjiang eastern central asia prior to the holocene the records show rare fossils with relatively low loi and more positive 13corg indicating low biomass organic carbon content under dry conditions which were unfavorable for the survival of snails in contrast tcf increased abruptly at the beginning of holocene coincident with a prominent increase in loi and a marked negative shift in 13corg furthermore tcf increased gradually to its maximum and 13corg became progressively negative with constant high loi from the early to late holocene the variations imply a trend towards wetter environment with optimal moisture precipitation relative humidity conditions occurring in the late holocene overall this holocene moisture evolution history could be attributed to the variations of westerlies strength modulated by the latitudinal temperature gradient and the insolation related evaporation should also be concerned

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

analyzing moon rocks the paradigm of a dry moon was recently challenged on the basis of reexamination of lunar samples collected during the apollo missions raising the possibility of a volatile rich lunar interior 1 6 several of these studies measured appreciable quantities of water reported as equivalent h oh or h2o and other volatiles e g cl f in the mineral apatite 4 6 which is ubiquitous in lunar basalts mare basalts see the figure however an accurate estimation of the water content of the magmatic liquid from which apatite formed and ultimately of the mantle source regions of mare basalts depends on a number of parameters in cases where apatite in a mare basalt formed through the process of fractional crystallization when newly formed crystals in a cooling magma are physically separated preventing any further interaction with the remaining melt it may not be possible to obtain any reliable estimates of the water contents of the parental magma and its source region on page 400 of this issue boyce et al 7 present an elegant numerical model applicable to mare basalt apatite formed through fractional crystallization to demonstrate that some of the highest water contents reported for lunar apatite can be reconciled with an original melt containing not much water at all these new results cast doubt on the utility of apatite volatile abundances in reliably estimating the water content of mare basalt source regions

loess rock sediment or soil what is missing for its definition abstract loess is commonly defined as an accumulation of windblown silt however the complex mechanisms that are responsible for most of the structural characteristics of loess require a more precise explanation the common definition of loess ignores a set of processes that start during and after the subaerial deposition of silt the term loessification has been used by a number of authors to refer to the quasi pedogenic quasi diagenetic processes that result in the typical aggregation of loess however these mechanisms are rarely described in detail depending on the researcher s background loess is classified as sediment soil or rock this review gives an overview on loess definitions through time and evaluates the main concepts related to loess formation several gaps of knowledge are identified that require a number of specific studies related to different aspects of loess formation in various environments we propose to 1 differentiate primary loessification which initializes the formation of loess structure from secondary loessification which takes place subsequently and 2 define loess like sediments as deposits that experienced loessification but were not transported aeolian mainly aeolian processes and loessification are of equal importance to define loess

the origin of the silt size quartz grains and minerals in loess abstract a permanent problem of the theories of loess formation is the origin of quartz grains of 20 50 m size this makes up the bulk of loess material a fundamental question for more than 100 years has been how the huge amounts of silt size grains were produced according to different explanations the coarse silt fraction could be produced by mechanical weathering caused by frost action insolation glacial grinding particles originating from till and outwash plains and finally from fine textured fluvial and lacustrine deposits molasse or commonly from sandy desert several kinds of processes can produce the initial material of loess according to berg 1964 and pecsi 1965 primarily in the course of loess formation pedogenic geochemical processes had produced the coarse silt grain size the unique loess fabric is a textured loam not merely a simple sediment recently nemecz and hartyani 1995 have collected samples in 10 m steps of soil and loess for a subsequent analysis loess paleosol samples were separated into 8 9 grain size fractions the mineralogical composition of fractions were determined quantitatively and plotted in three dimensions on typical granulometry diagrams for a hungarian loess paleosol series two maxima can be recognized one at

loess deposits in the northern kyrgyz tien shan implications for the paleoclimate reconstruction during the late quaternary article i nfo loess deposits on the northern slopes of the kyrgyz tien shan were examined their particle size characteristics show silt size dominancy n80 with minor contribution from sand 12 and clay 7 the loess was dated using optically stimulated luminescence osl and radiocarbon methods to define the timing of deposition the osl ages of fine and coarse quartz fractions were consistent with each other within 2 uncertainty level ex ceptseveralsamplesdepositedduringmis2 basedontheoslages fourmajorloessdepositionalperiodsarerec ognized in thenorthern kyrgyz tienshan during the late quaternary the holocene mis2 mis3 and mis4 the rate of dust accumulation in the northern tien shan during mis 2 was greater than that during mis 3 or mis 4 this implies that cold dry conditions varied significantly during the late quaternary in the study area the accumulation patterns of the kyrgyz loess deposits in the northern tien shan are closely related to climate fluc tuations during the late quaternary influenced by changes in the mid latitude westerlies asian summer mon soons and siberian high pressure shp systems during which there was no significant cessation of deposition 2013 elsevier b v all rights reserved

geochemical characterization and origin of southeastern and eastern european loesses serbia romania ukraine abstract the loess paleosol sections of batajnica stari slankamen serbia mircea voda romania and stary kaydaky ukraine were geochemically characterized based on discriminant analysis of major and trace elements the ratios of al ti fe ti and al fe the a cn k ternary plot and element enrichment depletion relative to the average composition of the upper continental crust the origin of the loess material in the southern pannonian basin vojvodina the lower danube basin dobrudja and the dnieper area was evaluated by comparison with the representative element composition of possible source areas and by considering the geomorphodynamic setting also the background values of the initial magnetic susceptibility of the loesses were taken into account for the lower danube basin dobrudja and the ukraine paleowind direction was reconstructed based on the geographic distribution of sandy soil texture and dunes related to river systems finally loesses were evaluated as possible samples of the average upper continental crust our results show that danube and dnieper loess areas can be clearly distinguished the former reveal higher al and fe contents the latter higher si zr hf content and indications of effective mineral and grain size sorting we can confirm that vojvodina loess originated from danube alluvial material and loess of the dnieper area from glaciofluvial sediments of the fennoscandinavian ice sheet the dobrudja loess derived also predominantly from danube alluvium but shows significant contribution of a second loess source probably the glaciofluvial sediments of the ukraine this was forced by northerly katabatic winds from the fennoscandinavian ice sheet whereas wnw winds prevailed in the western walachian plain the studied loesses reflect the average composition of the upper continental crust yet biases exist due to selective mineral element enrichment and depletion in the course of previous sedimentary recycling phases respectively material of all studied loess deposits seems to derive originally from sedimentary rocks

seasonal stable isotope evidence for a strong asian monsoon throughout the past 10 7 m y o of wet season rainfall was signi cantly morenegative 29 5 smow prior to 7 5 ma than after 26 5 smow if this change is attributable to a lessening of the amounteffect in rainfall this agrees with oral and soil geochemical datathat indicate increasing aridity beginning at 7 5 ma keywords tibetan plateau monsoon stable isotopes paleohydrology seasonality introductionthe tibetan plateau is the engine that drives the modern asianmonsoon by generating a high altitude region of low pressure in thesummer as the plateau heats and a region of high pressure in the winteras the plateau cools hastenrath 1991 during the summer warm airrises from the plateau pulling moist air off the ocean across the indiansubcontinent and into the highlands this results in heavy summer rain fall on the subcontinent the opposite occurs in the winter resultingin cold dry air spilling off the plateau and effectively excluding rainfrom the subcontinent thus the presence of a strong wet season dry season alternation implies the presence of a plateau broad and highenough to drive the monsoon the timing of the uplift of the plateau remains a matter of con siderable debate because there are few direct indicators of paleotopog raphy in the geologic record consequently past workers in tibet re lying on indirect indicators of uplift have proposed dates ranging from40 to 3 4 ma on the basis of initiation of potassic volcanism chunget al 1998 turner et al 1993 or extension on the plateau harrisonet al 1995 coleman and hodges 1995 changes in marine sedimen tation rates burbank et al 1993 sediment types rea et al 1998 or biota nigrini and caulet 1992 kroon et al 1991 and changesin stable carbon isotope and palynological patterns on the indian sub continent quade et al 1989 chen 1981 although different areasof the plateau may have risen at different times many workers haveinferred rapid simultaneous uplift of large areas of the plateau at 7 8ma by a process such as lithospheric delamination molnar et al 1993 this inference was based on the following approximately coevalphenomena a major change in plant communities of the indian sub continent quade et al 1989 and shifts in marine upwelling patternsthat are linked to an intense monsoon kroon et al 1991 althoughthere is strong evidence for signi cant climate change at 7 8 ma it isunclear whether this is the onset of the monsoon the oral transitionseems to have been a global rather than local phenomenon cerling etal 1997 and monsoonally driven upwelling may have already beenpresent by 10 12 ma nigrini and caulet 1992 kroon et al 1991 because there is an intimate association between the intense sea sonality of the modern monsoon and a high tibetan plateau and be cause evaporation can be unambiguously recognized in the d

abrupt environmental changes during the last 30 kyr in the southern margin of the taklimakan desert a record from an oasis abstract the taklimakan desert the largest sand sea in china is one of the most important sources of dust in the world millennial scale abrupt climate changes during the last glacial and holocene periods occurred in the region however these records remain poorly understood because dating eolian lacustrine and fluvial sediments and establishing reliable environmental proxies are challenging in this setting here we use accelerator mass spectrometry ams grain size and rb sr ratios of bulk sediments from an oasis sequence in the taklimakan desert while some 14c dates results are not in the stratigraphic order most of them can be grouped in four age groups during the last glacial we infer that reversals of radiocarbon age based on total organic carbon toc was controlled by organic carbon oc input from the regional carbon pool we selected 14c dates from the four age groups to develop an age depth model for a basin wide chronology peaks in a cumulative probability curve of radiocarbon dates with high rb sr ratios and fine mean grain sizes reveal four wet periods during the last glaciation and one wetter warmer period during the holocene the regional moisture variability appears to be influenced by the asian summer monsoon and mid latitude westerlies the holocene wetter warmer period facilitated human occupation of the oasis

revisiting the loess palaeosol sequence in paks hungary a post ir irsl based chronology for the young loess series in hungary many loess palaeosol sequences have been found to be discontinuous in order to allow for correlations with other quaternary records reliable chronologies are needed we therefore apply post ir infrared ir stimulated luminescence post ir irsl pirir290 dating to the uppermost 20 m of the loess sequence at paks the pirir290 ages are compared with blue quartz osl ages to test for potential age overestimation due to poor signal re setting and the observed good agreement is taken to imply that the more difficult to bleach pirir290 signal was reset prior to deposition our pirir290 based chronology reveals that most of the late pleistocene loess was deposited during marine isotope stage mis 3 and during the last glacial maximum lgm this is in disagreement with formerly published ages the discrepancy can most likely be explained by anomalous fading resulting in an age underestimate this conclusion is supported by our uncorrected standard irsl ages we further confirm that the basaharc double soil complex can be correlated with mis 7 the underlying loess and soils cannot be dated accurately because the pirir290 signal approaches saturation

variation in carbon isotopic composition over the past ca 46 000 yr in the loess paleosol sequence in central kazakhstan and paleoclimatic significance abstract we present a high resolution record of 13 c org variation from two loess sequences in central kazakhstan the variation shows that the vegetation was persistently dominated by c 3 plants over the past ca 46 000 yr the 13 c org signature was most likely an indicator of moisture and the moisture variation in central kazakhstan was associated with the precipitation in western europe the 13 c org indicated that moisture variation exhibited five stages decreasing during stage 1 ca 46 000 ca 31 500 yr bp increasing during stage 2 ca 31 500 ca 25 500 yr bp again decreasing during stage 3 ca 25 500 ca 19 000 yr bp fluctuating along a constant line during stage 4 ca 19 000 ca 5000 yr bp and increasing during stage 5 last ca 5000 yr our comparison demonstrated a general similarity between the 13 c org indicated moisture variation in central kazakhstan and the reconstructed precipitation variation in western europe the similarity implies that the moisture of the past ca 46 000 yr in central kazakhstan has been controlled or modulated by westerlies that brought water vapor from the north atlantic not only to western europe but also to central kazakhstan

geology mineralogy and geochemistry of fault controlled hydrothermal cu au mineralization in the shanmen volcanic basin se china abstract the yukeng banling deposit is a typical fault controlled hydrothermal cu au deposit in the shanmen volcanic basin svb se china ore bodies commonly occur as lodes lenses and disconnected pods dipping sw with vertical zonation of ore minerals ore related hydrothermal alteration is well developed on both sides of the veins dominated by silicification sericitization chloritization and argillation with a banded alteration zonation the mineralization can be divided into three stages stages i ii and iii native gold is present as veinlets in fractures of fine grained pyrite from stage ii zircon u pb and rb sr isochron ages indicate that the cu au mineralization is coeval with the caomen alkaline granite and xiaokeng quartz diorite both emplaced at ca 102 ma microthermometric measurements of fluid inclusions in quartz and sphalerite from stage ii veins indicate that the yukeng banling deposit is an epithermal deposit six ore related quartz grains have d h2o values of 69 to 43 and 18 o h2o values calculated using total homogenization temperatures that range from 2 0 to 0 7 all samples plot in an area between the magmatic field and the meteoric line suggesting that the ore forming fluids are derived from a mixed source of magmatic and meteoric waters 34 s values for eight pyrite separates range from 2 1 to 4 1 with an average of 1 7 and 34 s values for galena and sphalerite are 2 3 and 2 2 similar to magmatic sulfur four alkaline granite samples have pb isotopic ratios 206 pb 204 pb t 18 175 18 411 207 pb 204 pb t 15 652 15 672 and 208 pb 204 pb t 38 343 38 800 three quartz diorite samples have ratios 206 pb 204 pb t 207 pb 204 pb t and 208 pb 204 pb t of 18 277 18 451 15 654 15 693 and 38 673 38 846 respectively these age calculated lead isotopic data for alkaline granite are similar to those for the analyzed sulfides co ni ratios for stage ii pyrites range from 1 42 to 5 10 indicating that the yukeng banling deposit records the past involvement of magmatic hydrothermal fluids the isotope data together with geological mineralogical and geochronological evidence favor a primary magmatic source for sulfur and metals in the ore fluids mixing of the cu and au rich fluids with meteoric water led to precipitation of the cu au veins along nw trending faults the yukeng banling deposit the contemporaneous caomen alkaline granite and xiaokeng quartz diorite in the svb formed under an extensional setting due to high angle subduction of the paleo pacific plate the extensional setting facilitated the formation of cu and au rich magmas which was derived from enriched mantle and lower crust

loess stratigraphy of central asia palaeoclimatic and palaeoenvironmental aspects abstract the loess palaeosol succession of central asia is comparable with that of the loess plateau in north china palaeomagnetic investigations and palaeontological studies in south tadjikistan suggest a date of 2 2 5 ma for the oldest loess indicating that dust storms became frequent in the region since 2 2 5 ma bp under the prevalently arid and semi arid environments of central asia aeolian processes had a gradually increasing influence on subaerial sedimentation during the pleistocene however atmospheric aeolian processes in central asia have mainly developed in accordance with pleistocene climatic cyclicity without extremely high intensification during the late pleistocene as implied by the previous tl dating results the identification of loess and palaeosol horizons with respective glaciations and interglacials is sometimes disputable nevertheless the available data in spite of limited evidence characterise well developed palaeosols of the middle and late pleistocene as warm and wet intervals associated with interglacials palynological studies of loess sections show that loess and palaeosol horizons have palynological spectra that are sometimes difficult to interpret interregional loess palaeosol correlation with glacial interglacial events as well as with oxygen isotope records should be supplied by multidisciplinary investigations

late quaternary glaciation in the kyrgyz tien shan the tien shan of kyrgyzstan contains multiple moraines and drift from late quaternary glaciations the spatial temporal distribution of the glaciers inferred from the moraines suggests that the main factor controlling glacier advance here was the availability of moisture the dominant modern climatic signatures in northern central asia include orographic thunderstorms in summer cold and dry siberian high pressure cells in winter and westerly cyclonic storms from the north atlantic and eastern mediterranean in spring and fall changes in any of these systems during the late quaternary would have varied precipitation delivery to and glacier growth in the kyrgyz tien shan geomorphic mapping and reconnaissance level 10be cosmic ray exposure dating of moraine sequences in six drainages indicate that there were multiple maximum advances of similar extents and equilibrium line depressions across the range glaciers in the north and east of the kyrgyz tien shan last advanced to their maximum positions during marine oxygen isotope stage mis 5 and again during mis 4 while in the south and west of the range advance occurred during mis 3 in contrast to maritime europe and north america there is no evidence of a major glacial advance during mis 2 glacier advances during mis 2 and since were restricted to the vicinity of modern glaciers allowing the older glacial record to be preserved well

water in lunar anorthosites and evidence for a wet early moon water has been detected on the lunar surface and attributed to delivery by impacts and the solar wind to a dry early moon spectroscopic detections of water in lunar anorthosites from the apollo collection suggest that a significant amount of water is indigenous to the moon

loess soil sequence at toshan northern iran insights into late pleistocene climate change abstract the knowledge of palaeoclimate in iran is still limited however insight into the timing and the dynamics of quaternary climate change in iran might offer valuable information to improve the global palaeoclimate record the loess soil sequence of toshan provides the first high resolution record of late pleistocene climate dynamics in iran and complements the hitherto known sections at neka now deh and agh band to establish a pedostratigraphic record of the north eastern caspian lowland our spectroscopic and grain size analysis are combined to propose i a pedostratigraphical scheme for the sequence at toshan ii describe and estimate the degree of soil development of selected stratigraphical units iii infer palaeoclimatic information and provide iv a correlation with previous loess palaeosol records of n iran as based on pedostratigraphic assumptions the section at toshan hosts a strongly developed reddish brown argillic palaeosol bt as well as eight moderately to weakly developed brownish palaeosol horizons lacking clay illuviation features bw bwk these remnants of fossil soils are separated by finely textured loess and horizons that host characteristics of both loess and mineral subsoils cb cbk giving evidence for syngenetic soil formation the stratigraphical succession of palaeosols loess and syngenetically altered sediments covering the last ca 130 ka gives evidence for recurrent climate changes as well as fluctuations between dominance of soil formation or dust accumulation in relation to changes in moisture regime the formation of bt and bw bwk horizons is related to relatively humid and warm conditions likely corresponding with interglacial and interstadial climate

loess accumulation in the tian shan piedmont implications for palaeoenvironmental change in arid central asia whilst correlations have been made between the loess of europe and china deposits in central asia have remained largely overlooked by scientific investigation the nature of the relationship between loess accumulation and palaeoclimate at the core of the eurasian loess belt is particularly poorly understood here we reconstruct palaeoenvironmental change in central asia over the last 40 ky based on data from the remizovka loess profile in the northern foothills of the tian shan in southern kazakhstan our interpretations are based on synthesis of chronostratigraphic colour and magnetic susceptibility data supported by chronostratigraphies from two additional sites nearby maibulak and valikhanova all three sites record substantially increased loess accumulation during late mis 3 into the global last glacial maximum glgm at remizovka increased loess flux occurred in two pulses at c 38 25 ka and 22 18 ka with the intervening period involving incipient pedogenesis at maibulak two loess pulses at c 40 30 ka and c 28 22 ka are separated by a weakly developed paleosol which may date to the same time as pedogenesis at remizovka there is additional possible periglacial influence at maibulak from c 40 33 5 ka at valikhanova there is some age overlap between paleosol and loess samples but overall loess accumulation appears to have increased at c 42 35 ka c 30 ka and the glgm with pedogenesis occurring 40 ka and c 32 ka at all three sites holocene loess accumulation is minimal this period is characterised by pedogenesis the chronostratigraphic variability between our sites highlights a need to interrogate climate driven models for loess formation in piedmont environments we interpret our data in the context of regional palaeoenvironmental archives to indicate that loess accumulation increased coeval with mis 3 glacial advance in the tian shan which was facilitated by northward expansion of the asian monsoon and associated increase in precipitation we hypothesise that increased ice volume impeded teleconnections with the temperate zone westerlies to the north these were compressed against the piedmont resulting in increased wind strength and facilitating increased loess flux peak loess accumulation during the glgm occurred under colder drier climatic conditions with reduced but sustained glacial ice volume and persistent influence of the westerlies in the arid central asian piedmont loess belt in the absence of more widespread reliably dated palaeoenvironmental records from the region our data become of critical importance for understanding past environmental conditions in central asia relative to elsewhere in eurasia and globally

a stratigraphic framework for abrupt climatic changes during the last glacial period based on three synchronized greenland ice core records refining and extending the intimate event stratigraphy due to their outstanding resolution and well constrained chronologies greenland ice core records provide a master record of past climatic changes throughout the last interglacial glacial cycle in the north atlantic region as part of the intimate integration of ice core marine and terrestrial records project protocols have been proposed to ensure consistent and robust correlation between different records of past climate a key element of these protocols has been the formal definition and ordinal numbering of the sequence of greenland stadials gs and greenland interstadials gi within the most recent glacial period the gs and gi periods are the greenland expressions of the characteristic dansgaard oeschger events that represent cold and warm phases of the north atlantic region respectively we present here a more detailed and extended gs gi template for the whole of the last glacial period it is based on a synchronization of the ngrip grip and gisp2 ice core records that allows the parallel analysis of all three records on a common time scale the boundaries of the gs and gi periods are defined based on a combination of stable oxygen isotope ratios of the ice 18o reflecting mainly local temperature and calcium ion concentrations reflecting mainly atmospheric dust loading measured in the ice the data not only resolve the well known sequence of dansgaard oeschger events that were first defined and numbered in the ice core records more than two decades ago but also better resolve a number of short lived climatic oscillations some defined here for the first time using this revised scheme we propose a consistent approach for discriminating and naming all the significant abrupt climatic events of the last glacial period that are represented in the greenland ice records the final product constitutes an extended and better resolved greenland stratotype sequence against which other proxy records can be compared and correlated it also provides a more secure basis for investigating the dynamics and fundamental causes of these climatic perturbations

a high resolution absolute dated late pleistocene monsoon record from hulu cave china oxygen isotope records of five stalagmites from hulu cave near nanjing bear a remarkable resemblance to oxygen isotope records from greenland ice cores suggesting that east asian monsoon intensity changed in concert with greenland temperature between 11 000 and 75 000 years before the present yr b p between 11 000 and 30 000 yr b p the timing of changes in the monsoon as established with 230th dates generally agrees with the timing of temperature changes from the greenland ice sheet project two gisp2 core which supports gisp2 s chronology in this interval our record links north atlantic climate with the meridional transport of heat and moisture from the warmest part of the ocean where the summer east asian monsoon originates

an abrupt shift in dust source on the chinese loess plateau revealed through high sampling resolution osl dating abstract the source of dust that forms the extensive deposits of loess exposed on the chinese loess plateau is highly debated in particular it is not clear whether sources can change abruptly within individual loess units or whether local influences on source can override the influence of far travelled components high vertical sampling resolution 10 40 cm optically stimulated luminescence osl dating of sediments on the loess plateau in china has been successful in providing detailed independent age models for loess accumulation here osl behaviour is used to infer a shift in loess sediment source during the last glacial period osl dating procedures have often utilised the widely applied single aliquot regeneration sar protocol on quartz grains detailed sar osl dating of the last 45 ka of sedimentation at beiguoyuan section on the north of the loess plateau demonstrates anomalous and statistically significant age increases and scatter in age estimates in samples from a c 2 5 m unit at about 20 ka compared to samples above and below many of these samples also fail internal dose recovery tests and show anomalous luminescence signal properties deconvolution of osl decay curves into first order components reveals that many of the age overestimating samples have a significant ultrafast component this behaviour is restricted to the 2 5 m segment and is only likely to be uncovered using high sampling resolution luminescence analysis combined with heavy mineral grain size and geochemical evidence this suggests that the source of material in this unit abruptly shifted at the last glacial maximum potentially to a local source rather than well mixed and recycled multiple distant sources as appears to be the case at other times at the site and other studied sections on the loess plateau the environmental causes of this source shift may be tied to abrupt climate change during the last glacial maximum and demonstrate the highly dynamic nature of the locations of dust generation during the last glacial period the change in source also adds complexity to standard climate proxy analyses of loess using sediment properties

the last million years recorded at the stari slankamen northern serbia loess palaeosol sequence revised chronostratigraphy and long term environmental trends abstract the stari slankamen loess palaeosol section is located on the northeastern part of the srem loess plateau vojvodina region north serbia the c 40 m thick cliff comprises loess intercalated with 9 major palaeo pedocomplexes and can be considered to be one of the most important quaternary sections in the carpathian panonnian basin here we present new magnetostratigraphic and aminostratigraphic evidence that demonstrates the importance of the site in terms of its age and the long term palaeoclimatic record it preserves directional palaeomagnetic data obtained through alternating field demagnetization demonstrates the presence of reversed polarity below a profile depth of 36 m indicating a matuyama chron age of this interval this interpretation is confirmed by new high resolution palaeomagnetic investigations 434 oriented samples from the lower part of the profile the new magnetic susceptibility record and aminostratigraphy indicate a missing pedocomplex v s2 with an erosional unconformity represented by a distinct gravel layer the combined new magnetostratigraphic and aminostratigraphic based age model requires a significant revision of hitherto published chronostratigraphic subdivisions at the site the relative completeness and long time frame covered by the section is unusual in european loess sequences hence the sequence could form the basis of a continental scale stratigraphic scheme that would alleviate much current chronostratigraphic uncertainty and enable more broad scale climatic reconstructions the section also provides a rare opportunity to investigate detailed and long term climatic change over the middle pleistocene in a region influenced by air masses originating from high and middle latitudes as well as the north atlantic and mediterranean the changing relative importance of these air masses through time provides insight into local and regional atmospheric systems and their evolution through the last c 1 ma the section can thus be considered as one of the key climatic archives in the europe

source fingerprinting loess deposits in central asia using elemental geochemistry with bayesian and glue models abstract the provenance of loess deposits in central asia is largely unexplored accordingly the goals of this research were to test and compare the performance of two different models generalized likelihood uncertainty estimation glue and a bayesian model for quantifying the uncertainty in source apportionment estimated for 46 target loess samples collected in the ili basin in eastern central asia model performance was evaluated using goodness of fit gof mean absolute fit maf and virtual mixtures vm in combination with root mean square error rmse and mean absolute error mae our dataset comprised 132 surficial samples collected from three potential sources comprising river alluvium n 29 sand dunes n 35 and topsoils n 68 all samples were analysed for elemental geochemistry six geochemical properties co er y ga dy and pb were selected in a composite fingerprint which classified 83 of the samples from the three source categories correctly based on both models source contributions to the loess samples were in the following order topsoils river alluvium sand dunes based on the gof and maf tests both models were accurate in predicting measured tracer concentrations in the loess samples the bayesian model was slightly more accurate mean rmse 1 6 mean mae 1 8 than the glue mean rmse 5 0 mean mae 4 7 model in predicting known source contributions overall our results provide confirmation that application of source fingerprinting with elemental geochemistry and uncertainty modelling techniques is useful for identifying the provenance of loess sediments in arid and desert environments

dust deposition and climate in the carpathian basin over an independently dated last glacial interglacial cycle dust deposition and climate in the carpathian basin over an independently dated last glacial interglacial cycle

onset of asian desertification by 22 myr ago inferred from loess deposits in china the initial desertification in the asian interior is thought to be one of the most prominent climate changes in the northern hemisphere during the cenozoic era1 2 3 4 but the dating of this transition is uncertain partly because desert sediments are usually scattered discontinuous and difficult to date here we report nearly continuous aeolian deposits covering the interval from 22 to 6 2 million years ago on the basis of palaeomagnetic measurements and fossil evidence a total of 231 visually definable aeolian layers occur as brownish loesses interbedded with reddish soils this new evidence indicates that large source areas of aeolian dust and energetic winter monsoon winds to transport the material must have existed in the interior of asia by the early miocene epoch at least 14 million years earlier than previously thought3 5 regional tectonic changes and ongoing global cooling are probable causes of these changes in aridity and circulation in asia

molecular records of continental air temperature and monsoon precipitation variability in east asia spanning the past 130 000 years our current understanding of past changes in east asian summer monsoon easm precipitation intensity derives from several loess paleosol sequences and oxygen isotope 18o records of well dated stalagmites although temperature is generally presumed to have had minimal impact on easm records past air temperature dynamics over east asia are so far relatively poorly understood mainly due to the lack of tools to reconstruct continental paleotemperatures here we report a high resolution record of east asian air temperature over the past 130 000 years based on soil bacterial lipid signatures preserved in a loess paleosol sequence from the mangshan loess plateau in china we find that maximum local insolation is the main driver of air temperature although greenhouse gas concentrations and southern hemisphere climate may influence temperature at times when insolation is weak causing a decoupling with easm precipitation intensity direct comparison of our temperature record with precipitation induced changes in past soil ph derived from the same suite of lipids confirms this decoupling subsequent cross spectral analysis of the two molecular proxy records reveals that variations in monsoon precipitation consistently lag those in air temperature throughout the whole record at the dominant precession band the length of this lag is variable however and increases as glaciation develops this observation is consistent with an increasing influence of northern hemisphere ice sheets on the modulation of easm response to insolation forcing during ice ages

origin weathering and geochemical composition of loess in southwestern hungary abstract loess geochemistry generally reflects paleo weathering conditions and it can be used to determine the average composition of the upper continental crust ucc in this study major and trace element concentrations were analyzed on loess samples from southwestern hungary to determine the factors influencing their chemical compositions and to propose new average loess compositions all studied loess samples had nearly uniform chemical composition suggesting similar alteration history of these deposits chemical index of alteration values 58 69 suggested a weak to moderate degree of weathering in a felsic source area typical non steady state weathering conditions were shown on the al 2 o 3 cao na 2 o k 2 o patterns indicating active tectonism of the alpine carpathian system during the pleistocene whole rock element budgets were controlled by heavy minerals derived from a felsic magmatic or reworked sedimentary provenance geochemical parameters indicated that dust particles must have been recycled and well homogenized during fluvial and eolian transport processes

abrupt climatic events recorded by the ili loess during the last glaciation in central asia evidence from grain size and minerals abstract the loess record of central asia provides an important archive of regional climate and environmental changes in contrast to the widely investigated loess deposits in the chinese loess plateau central asian loess paleosol sequences remain poorly understood here we present an aeolian loess section in the southern ili basin based on granularity and mineralogical analyses we reconstruct climatic changes during the last glaciation the results indicated that most of the abrupt climatic events such as dansgaard oeschger events and heinrich events were imprinted in this loess section although their amplitudes and ages showed some differences compared with the millennial oscillations recoded in loess and stalagmites in east asia the arid central asia responded more sensitively to the warming events than to the cooling events the shifting trajectory of westerlies across central asia played an important role in dust deposition during the stadials the north atlantic climatic signals may have been transmitted from central asia to the east asian monsoon regions via the westerlies

the formation of loess deposits in the tashkent region and parts of central asia and problems with irrigation hydrocollapse and soil erosion abstract there are large problems of irrigation hydrocollapse and soil erosion associated with the loess deposits of central asia to get to grips with these we need a clear view of the nature and formation of the loess and in this region there are still disputes and disagreements and controversies important events in the loess deposit formation process can be identified and studied and relative significances assigned there are large loess deposits in the vicinity of tashkent in the north east of uzbekistan these were mapped and studied for many years by g a mavlyanov and associates they used a terminology which appears to be based on pavlov s nineteenth century usage and developed a polygenetic formation theory for loess deposits this was a formation theory very much associated with central asia and essentially favouring a proluvial mechanism a speculative look at the deposits near tashkent allows alternative terminologies and formation mechanisms to be considered in particular the widespread soviet antipathy to aeolian deposition can be examined the deposits associated with the chirchik river upstream of tashkent might be affected by the pavlov mechanisms but could be topped by aeolian deposits the collapse of loess when wetted is controlled by the nature of the ground and is a very significant interaction of soil and water in particular in central asia hydrocollapse and water erosion are closely related and are controlled by the complex nature of loess ground dust clouds in eastern uzbekistan are largely loess related but in the west dust material is raised from the drying aral sea bed this is often clay mineral agglomerate material and can carry dangerous pollutants