sources of non glacial loess size quartz silt and the origins of desert loess abstract descriptions of peridesertic loess deposits and possible non glacial origins for silt size quartz are reviewed including direct release from weathered bedrock results from salt and frost weathering experiments are presented and methods by which sufficient energy can be imparted to sand size grains to release silt size fragments are identified these fragments may then be entrained by aeolian or fluvial action results from fluvial comminution experiments indicate that high energy mixed sediment fluvial systems may be very effective in generating quartz silt purely aeolian attrition is also seen as a major source of silt size and finer material results from aeolian abrasion experiments performed using crushed quartz sand are complemented by trials using sands from deeply weathered granite and pannonian sands from hungary field and laboratory observations are therefore seen to argue for the existence of deposits that can be classified as desert loess

luminescence dating of proglacial sediments from the eastern alps the potential of optically stimulated luminescence osl for dating proglacial deposits is tested here at three last glacial key sites in the eastern alps this was undertaken using both sand sized feldspar and quartz grains as well as fine silt sized material the samples reveal rather poor luminescence intensities of the investigated quartz grains and it is also clearly demonstrated that several of the deposits were incompletely bleached prior to deposition bleaching experiments were carried out and different approaches for extracting the aliquots where the osl was completely bleached prior to burial were tested applying different osl measurement techniques and analytical procedures we investigated which approach was most appropriate for dating known age proglacial sediments best results were achieved using single aliquot regenerative dose methodology on coarse grain quartz and feldspar samples in combination with the approach of preusser et al 2007 luminescence dating of proglacial sediments from switzerland boreas in press for ed calculation

correlation and interpretation of paleosols and loess across european russia and asia over the last interglacial glacial cycle abstract loess paleosol sequences of the last interglacial glacial cycle are correlated from european russia to central siberia and the chinese loess plateau during cold periods represented by marine oxygen isotope stages ois 2 and 4 loess deposition dominated in the russian plain and the loess plateau in central siberia loess deposition took place also but five to seven thin weakly developed paleosols are identified in both stages ois 3 in the chinese loess plateau near yangchang consists of a loess bed that is flanked by two weakly developed paleosols at kurtak siberia ois 3 is represented by two distinct stacked paleosols with no loess bed separating the paleosols in the russian plain ois 3 consists of a single possibly welded paleosol representing upper and lower stage 3 climates brunisols and chernozems dominate the profiles in china and siberia whereas regosols luvisols and chernozems are evident in the northern and southern russian plain respectively ois 5 is represented in china and the russian plain by pedo complexes in a series of welded soils whereas in contrast the kurtak site consists of six paleosols with interbedded loess the paleosols consist largely of brunisols and chernozems although the three areas examined have different climates geographical settings and loess source areas they all had similar climate changes during the last interglacial glacial cycle

the evidence for paraglacial sedimentation and its temporal scale in the deglacierizing basin of small river glacier canada abstract spatially sampled suspended sediment data from extra channel surfaces of different ages during rainfall events were used to infer the timescale of landscape adjustment to little ice age lia deglacierization at small river glacier canada surface ages were determined by aerial photograph interpretation turbidimeters were installed in three ephemeral channels on young mature and old surfaces and their response to rainfall events of different magnitudes recorded results showed young ice proximal surfaces exposed since 1977 were increasingly vulnerable to mobilization during rainfall events a suspended sediment response from old surfaces exposed since 1910 was recorded for only three events with 5 and 30 year return periods the intensity and duration of rainfall events therefore had to increase in magnitude to mobilize sediment on surfaces of increasing maturity hysteresis in the channel suspended sediment response further confirmed the dependence of surface response on rainfall event magnitude the rapid temporal decline in surface response indicated that surface armoring or sediment exhaustion is stabilizing surfaces within decades of exposure from the lia maximum ca 1910 at small river glacier however further perturbation for example by glacial advance or extreme climatic events would likely modify the pattern of suspended sediment yields by changing terrain surface mobilization thresholds and reconfiguring channel sediment stores we therefore suggest that it is difficult to determine when paraglacial sedimentation ceases to influence suspended sediment yields and therefore significantly limiting the usefulness of the term to describe the period of suspended sediment yield adjustment following deglacierization

ultra rapid landscape response and sediment yield following glacier retreat icy bay southern alaska abstract glacial retreat and opening of taan fjord an arm of icy bay alaska in the last two decades drove a base level fall of 400 m at the outlets of four tributary valleys in the region of the current tyndall glacier terminus response in the tributary valleys to this base level fall includes evacuation of stored sediment incision of slot gorges into bedrock and landsliding on valley walls fluvial transfer of eroded bedrock glacial deposits and stored nonglacial fluvial deposits after 1983 resulted in progradation of fan deltas toward the fjord centerline at the outlet of each of the four catchments in the largest nonglacial tributary valley 0 08 km 3 8 of the 0 59 km 3 of 500 m thick stored fluvial and colluvial deposits has been transferred to the adjacent fjord a percentage of the fjord sedimentation in the last two decades thus includes material eroded from bedrock and stored in the landscape during the previous glacial expansions distal deltaic deposits extend across the fjord floor and likely interfinger with distal proglacial deltaic deposits sourced from the tyndall glacier a paraglacial landscape response such as the one exhibited in upper taan fjord where sediment delivery to fjords from tributary sources in synchrony with sediment produced by primary bedrock erosion by glaciers helps to explain the order of magnitude discrepancy between sediment yields from alaskan tidewater glaciers on 10 0 to 10 2 year timescales and sediment yields and exhumation rates on 10 4 to 10 6 year timescales

climatic interpretation of a 1 9 ma environmental magnetic record of loess deposition and soil formation in the central eastern pampas of buenos aires argentina abstract much of what we know about quaternary climate has been learned from sedimentary records from the world s oceans with the exception of the extensive studies of the chinese loess paleosol sequence and more recent studies of long lake records there are few long terrestrial climate records particularly from the southern hemisphere the loess record of argentina provides an important opportunity to further our understanding of climate change from a terrestrial environment but its complexity and discontinuity have led to difficulty in formulating a climatological model of depositional and pedogenic processes in this study we present one of the longest and most continuous loess loessoid records from the central eastern pampas of argentina our age model is based on optically stimulated luminescent dates and a paleomagnetic reversal stratigraphy and indicates a basal age around 1 9 ma within the age model uncertainties we characterize the environmental magnetic properties associated with loess deposition and soil formation with respect to wind patterns moisture availability and temperature major changes in magnetic grain size are linked to a differential northward shift of the subtropical high pressure cell during glacial periods we suggest that coarser finer magnetic grains correspond to weaker stronger glacial periods when the high pressure cell is located in a more southerly northerly position and the source region is more proximal distal to our study area an abrupt increase in the ultrafine grained magnetic material around 0 9 ma is related to an increase in moisture transport from the south atlantic driven by an increase in summer sea surface temperatures at the mid pleistocene transition 1 ma in addition to these grain size variations there is a relative decrease in the amount of goethite compared to hematite beginning around 0 5 ma which has been related to the temperature increase observed after the mid brunhes event 450 ka in the epica ice core temperature record a more detailed comparison to insolation indicates that for portions of the record ferrimagnetic minerals are depleted during periods of low insolation this result suggests that argentine loess deposition and soil formation follows a model more similar to the alaskan loess sequences than the chinese loess sequences although further work is needed to validate the models and mechanisms proposed in this study our record indicates that the mineral magnetic properties of the loess and paleosol deposits record major changes in deposition and soil formation and provide insight into possible mechanisms relating to global and or hemispheric climate change

late quaternary aeolian sedimentation in central and south eastern tibet abstract the geomorphology and the cover sediments in the central and south eastern part of the tibetan plateau provide information about climatic change luminescence dating of aeolian and colluvial silts on top of different moraine sequences provides the first indications for the timing of these sediments during the late quaternary and holocene although there is a widespread cover of aeolian mantles in tibet only a few papers have focussed on them up to now samples from silt layers on top of pleistocene moraines or solifluction debris from central and southern tibet at elevations above 4000 m asl provide early holocene ages in most sections the aeolian silt on top of the bomi moraine in southeastern tibet situated at an elevation of about 3000 m asl provides an age of 25 ka according to geomorphological investigations the bomi moraine dates from the last ice age which can be confirmed by the luminescence data moreover one sample from a silt layer in between gravel layers xainxa is also pleistocene in age according to its sedimentary and geomorphological situation in the tibetan plateau pleistocene loess mainly occurs below 4000 m asl the holocene material a more sandy silt lying above 4000 m asl however aeolian material capping the moraines provides only minimum ages for the terminal moraines the time interval between glacier retreat and the accumulation of aeolian sediments may be several thousand years the most important fact is the trapping of dust in general lakes and a denser vegetation cover are or were the main traps for the typical loess found in the mountain areas of the tibetan plateau

continuously stratified flows across an alpine crest with a pass shallow and deep fohn shallow and deep alpine fohn flows are analyzed within the framework of continuously stratified hydraulics a distinguishing upstream feature of these flows is the presence of stagnant nearly well mixed layers above and beneath the moving stratified fluid these layers isolate the moving stratified fluid which has a self similar parabolic like velocity distribution from the stratified fluid above and beneath the shallow and deep realizations of these flows were found on 20 and 21 october 1999 during the mesoscale alpine programme the temporal evolution from shallow to deep fohn was captured with a sequence of radiosondes automatic weather stations an instrumented car and research aircraft flights copyright 2007 royal meteorological society

stratigraphy and palaeoclimatic significance of late quaternary loess palaeosol sequences of the last interglacial glacial cycle in central alaska abstract loess is one of the most widespread subaerial deposits in alaska and adjacent yukon territory and may have a history that goes back 3 ma based on mineralogy and major and trace element chemistry central alaskan loess has a composition that is distinctive from other loess bodies of the world although it is quartz dominated central alaskan loess was probably derived from a variety of rock types including granites metabasalts and schists detailed stratigraphic data and pedologic criteria indicate that contrary to early studies many palaeosols are present in central alaskan loess sections the buried soils indicate that loess sedimentation was episodic or at least rates of deposition decreased to the point where pedogenesis could keep ahead of aeolian input as in china loess deposition and pedogenesis are likely competing processes and neither stops completely during either phase of the loess soil formation cycle loess deposition in central alaska took place before and probably during the last interglacial period during stadials of the mid wisconsin period during the last glacial period and during the holocene an unexpected result of our geochronological studies is that only moderate loess deposition took place during the last glacial period our studies lead us to conclude that vegetation plays a key role in loess accumulation in alaska factors favouring loess production are enhanced during glacial periods but factors that favour loess accumulation are diminished during glacial periods the most important of these is vegetation boreal forest serves as an effective loess trap but sparsely distributed herb tundra does not thus thick accumulations of loess should not be expected where tundra vegetation was dominant and this is borne out by modern studies near the treeline in central alaska much of the stratigraphic diversity of north american loess including that found in the central lowlands the great plains and alaska is explained by a new model that emphasizes the relative importance of loess production factors versus loess accumulation factors

respective roles of remote and local wind stress forcings in the development of warm sst errors in the south eastern tropical atlantic in a coupled high resolution model processes involved in the development of the warm sea surface temperature sst bias in the tropical south eastern atlantic seta in a high resolution hr version of the cnrm cm model are evaluated based on full field initialized seasonal hindcasts starting at 1 february of each year for 2000 2009 whereas the initial sst growth is likely associated with local atmospheric forcing its further development is due to remote oceanic processes a mixed layer heat budget analysis in seta indicates a spurious warm horizontal advection observed as far as south of 25 s that appears at the beginning of march it is associated with an erroneous oceanic mean state at the equator resulting from the mean equatorial westerly wind bias a sensitivity experiment with corrected wind stress over the equatorial region suggests that the remote forcing explains about 57 of the seta sst bias in march may comparison with a lower resolution lr version of the model reveals that in general similar processes are responsible for the sst bias in both models a strong reduction of the bias in the hr model is observed only over the near coastal southern benguela region due to a better representation of atmospheric and oceanic processes controlling the coastal upwelling overall the results of the inter comparison of the seta sst bias evolution in different sensitivity experiments performed in this study can be interpreted in terms of the relative contributions of erroneous warm horizontal advection associated with equatorial forcing and cold horizontal advection associated with local offshore ekman transport

175 years of loess research in germany long records and unconformities abstract loess research in germany has a long tradition dating back to the early works of von leonhard von leonhard k c 1823 1824 charakteristik der felsarten 3 bde 772 s heidelberg j engelmann and his contemporary geoscientists ever since that time german researchers and loess research within germany have provided important contributions to the international state of the art to date however perceptual unconformities have existed in both the continuity of loess research in germany and the interpretation of the loess record in both the palaeoecological and the stratigraphic sense this paper briefly highlights some relevant periods of loess research in germany and the approaches adopted from the early days to the present the development of a refined stratigraphy of the last glacial loess in germany during the second half of the 20th century is reviewed in the contribution by a semmel fundamental contributions were first published by schonhals freising and brunnacker in the course of the subsequent work of the loess commission of the international union for quaternary research inqua the stratigraphy of the wurmian loess has since been refined in almost all loess regions of germany and schemes consistent in their fundamental features have been published in recent years contributions have focussed on age determination in particular those based on luminescence dating techniques

quaternary stratigraphy and optical dating of loess from the east european plain russia abstract optical dating of silt sized potassium feldspar grains was found to be suitable for dating the formation of key loess units at two sites on the central east european plain loess bracketing the bryansk palaeosol yielded optical ages in agreement with the well dated radiocarbon chronology when corrected for anomalous fading optical ages from loess bracketing a significant pedogenic unit below the bryansk palaeosol support our lithostratigraphic interpretation that it is the mezin palaeosol complex and its formation during the last interglaciation oxygen isotope stage ois 5 optical ages from a stratigraphically older loess unit directly underlying a significant 10 m thick till unit in conjunction with its regional stratigraphic context suggest that the loess and the till were deposited during the dnieper glaciation which probably occurred during ois 6

a late quaternary magnetic record of tunisian loess and its climatic significance magnetic measurements for a 10 m loess palaeosol sequence from the matmata plateau in southern tunisia show significant down profile variations in concentrations of pedogenic ferrimagnetic minerals the sequence appears to correlate with regional and global records of climate change over the past 70 kyr there is strong evidence from comparisons of mineral magnetic properties in modern soils and palaeosols that the sequence holds a proxy record of winter precipitation

regional grain size variations in aeolian sediments along the transition between tibetan highlands and north western chinese deserts the influence of geomorphological settings on aeolian transport pathways sediment distribution is investigated applying grain size analysis to 279 surface samples from the transitional zone between high mountains qilian shan and their arid forelands hexi corridor in north western china six main sediment types were classified medium scale 103 m geomorphological setting is carefully considered as it may play an important role concerning sediment supply and availability a tripartite distribution of sedimentological landscape units along the mountain to foreland transition is evident aeolian sediments e g loess and dune sands are widespread they are used to identify aeolian transport pathways the mu fs ratio 5 11 m 48 70 m among primary loess opposes the two grain size fractions being most sensitive to varying accumulation conditions the first fraction is attributed to long distance transport in high suspension clouds whereas the latter represents local transport in saltation mode the ratio shows strong correlation with elevation r2 0 77 thus it indicates a relatively higher far traveled dust supply in mountainous areas 3000 m above sea level a s l compared to the foreland the contribution of westerlies to high mountain loess deposits is considered likely hereby the influence of the geomorphological setting on grain size composition of aeolian sediments becomes apparent the contribution from distant dust sources is ubiquitous in the study area however the far distance contribution may be reduced by the availability of fine sand provided in low topography settings plain foreland areas support fine sand deflation from supplying river beds allowing the formation of sandy loess in foreland areas and intramontane basins in contrast high mountain topography inhibits strong sand deflation into loess deposits eastern parts of the hexi corridor show higher aeolian sand occurrence in contrast the western parts are dominated by gravel gobi surfaces this is attributed to higher sand supply in eastern parts provided by the badain jaran desert and fluvial storages as sand sources copyright 2014 john wiley sons ltd

magnetic properties of loess deposits in australia and their environmental significance abstract there are vast dry areas in australia but few loess sections have been reported mackenzie s waterholes creek mwc profile in new south wales was the deepest and first dated loess profile in this paper various measurements of magnetic parameters from mwc were carried out and comparison was made with those of luochuan profile which lies in the central chinese loess plateau clp the types of magnetic minerals are similar to the clp magnetite maghemite limonite and hematite however the magnetic properties of the australian aeolian sediment are quite different frequency dependent magnetic susceptibility fd is rather high while values of magnetic susceptibility are low the relative content of hard paramagnetic magnetic components is much higher than clp whereas the content of maghemite and hematite is much less furthermore hard magnetic minerals increase with depth while soft maghemite decrease with depth maghemite is more sensitive than magnetite under pedogenic condition of waterlogged environments it increases along with enhancement of magnetic susceptibility in luochuan section however decreases in mwc profile this very likely indicates that the pedogenesic processes in mwc took place under an environment in which maghemite magnetite were unstable the modern annual precipitation in the mwc area is 924 mm which is about 300 mm higher than that in luochuan that extra moisture may lead mwc to exceed the stable range for maghemite magnetite those minerals therefore were gradually converted to more stable goethite causing magnetic susceptibility to decrease fe and mn nodules are abundant in the lower part of section implying mildly reducing conditions that allowed fe and mn to be mobilised and enriched in near the oxidation front indicating that under waterlogged and reducing conditions wind blown maghemite magnetite were transformed to iron hydroxides such as goethite limonite or other paramagnetic minerals resulting in reduced magnetic susceptibility the susceptibility from most of the section shows a generally positive relationship to the loess particle size and seems to fit the alaskan wind vigor model however fe chemical weathering and movement in mwc suggests that the precondition for the wind vigor model cannot be satisfied and that the susceptibility variation can only be explained by pedogenesis

geomorphological and palaeoclimate dynamics recorded by the formation of aeolian archives on the tibetan plateau abstract aeolian sediments are an important archive for palaeoclimate reconstructions on the tibetan plateau the accumulation of aeolian sediments and the formation of palaeosols are used as a proxy for dry and wet phases respectively during the last decade the number of osl optically stimulated luminescence ages of aeolian sediments has been rapidly increasing this study summarises the results from more than 300 individual osl ages despite the widespread occurrence of aeolian sediments on the tibetan plateau nearly all osl samples are located on the northeastern and the southern part in most regions the strongest accumulation occurred during the late glacial and in the early holocene this coincides with the strengthening of the asian summer monsoon on the tibetan plateau and wetter climate conditions after the relatively dry glacial times the development of a sufficient vegetation cover acting as a sediment trap seems to be an important requirement for the preservation of aeolian archives short dry periods like the younger dryas led to a more enhanced aeolian accumulation without destruction of previously formed archives in some regions the formation of palaeosols occurred mainly during the wet early and mid holocene but the number of ages is relatively small in contrast a second phase of aeolian accumulation during the late holocene was related to the weakening of the asian summer monsoon and drier climate conditions this indicates that the reaction of aeolian accumulation on the tibetan plateau depends on the previous climate state a comparison between the osl ages from aeolian sands and loess deposits yields a different timing of deposition of these two sediment types while the sand deposits in different basins resemble wet and dry phases loess deposits show no common signal between the analysed areas this indicates an influence of local factors such as varying source areas and erosive processes on the slopes in general the aeolian archives in the high mountain environment are governed by numerous factors besides the climatic influence

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

periglacial slope deposits and their pedogenic implications in germany abstract disconformities within soil parent materials are frequently reported from locations throughout the world but they are rarely within the goals of systematic research this article provides an overview of the current state of knowledge on such materials and their pedogenic relevance in germany it intends to encourage further discussion on stratified soils in other parts of the world the slope deposits in germany are divided into 1 the upper layer that is ubiquitously distributed and displays a relatively constant thickness 2 the intermediate layer that is restricted to flat relief to hollows and to lee ward facing slopes and 3 the basal layer that is rather widespread again both the upper and intermediate layer contain intermixed loess while the basal layer is free of loess these layers were mainly formed by periglacial solifluction such deposits are referred to as cover beds the upper layer formed during the younger dryas within a relatively short episode in contrast the lower layers may be diachronous nevertheless they display recurring vertical sequences this is probably due to the fact that loess free layers usually could not deposit as long as there was loess in the environs thus the last phase of surface wash during which older loess was removed determines the age of the lower layers the composition of the layers differs reflecting the varying portions of loess and of rock allocated from upslope in twofold sequences the cover beds influence the formation of the soils as they provide weathered material and as their boundaries where properties such as texture and bulk density abruptly change determine the soil horizon boundaries some pedogenic processes are favored oxidation depletion of clay or hindered podzolization due to the loess content of the upper layer even exceeding this the dominant loess content of an intercalated intermediate layer in threefold sequences may completely decouple pedogenesis from bedrock influence in all soil formation is largely influenced by the constellation of cover beds at any given site

the siberian loess record and its significance for reconstruction of pleistocene climate change in north central asia abstract the siberian loess represents the most significant terrestrial proxy record of quaternary climatic history in northern asia loess is extensive in southern siberia between the irtysh basin in the west and the angara basin in the east palaeoenvironmental multi proxy data magnetic susceptibility ms grain size caco 3 toc pollen etc from high resolution loess palaeosol sections provide evidence for a strongly fluctuating climatic sequence in north central asia during the late quaternary displaying the globally diagnostic sequences found in the deep sea oxygen isotope records ms provides the most continuous and detailed record encompassing the last two interglacial glacial cycles in loess sections in the minusinsk basin yenisei area and on the northern altai plains evidence for periodic atmospheric shifts is provided by gradual changes in the main vegetation zones with parkland steppe and mixed taiga during warm interglacial interstadial stages being replaced by boreal tundra forest and arid periglacial tundra steppe during stadials climatic pulses from warm intervals to cold are recorded by incipient forest steppe tundra gleysols the occurrence of the highest sediment accumulation rates in glacial stages ois 4 and ois 2 in the southern plains and depressions indicates that the most intensive aeolian dust deposition followed the glacial maxima with the most recent interval dated to ca 19 15 ka bp because of its zonal distribution and pronounced climatic continentality the siberian loess region represents an important data source for reconstructing past climates in the northern hemisphere it provides a key to the correlation of other loess regions within the west east eurasian continental zone

seismic reflection study of recessional moraines beneath lake superior and their relationship to regional deglaciation abstract approximately 8000 km of continuous seismic reflection profiles throughout lake superior were examined for evidence of recessional moraines and other ice margin deposits associated with the retreat of late wisconsin ice these features are correlated with the record of glacial lake evolution in western lake superior an offlapping sequence of glacial and glacial lacustrine dediments overlying bedrock is recognized in west central lake superior that is progressively younger to the northeast the sequence underlies more recent glaical lacustrine and postglacial sediments four facies are recognized on the basis of geomorphologic and acoustic properties and are interpreted to represent a southwest to northeast assemblage of proglacial stratified drift facies a drift in major end moraines facies b till deposited as glacial retreat resumed or possibly late stage ablation till facies c and basal till facies d the prominent moraines of facies b are unusually thick and are believed to mark the ice margin shorelines of successive major proglacial lakes that formerly occupied parts of western lake superior the moraines are tentatively correlated with glacial lake duluth unit 1 glacial lake washburn unit 2 and glacial lake beaver bay unit 3 the most prominent of lakes drained via the progressively lower outlets via the moose lake brule st croix rivers the huron mountains and the au train whitefish regions respectively

upper pleistocene loess stratigraphy in southern germany abstract the detailed loess paleosol sequences of southern germany provide a highly sensitive record of the regional climate and environmental changes of the upper pleistocene combined infrared stimulated luminescence irsl and thermoluminescence tl dating was carried out on loess and loess derivatives at upper pleistocene type sections from the mainz basin the middle neckar valley and the alpine foreland with the aim of setting up a reliable chronological framework for the past 130 000 years the irsl and tl age estimates are in agreement with the geological estimates up to 70 000 years however the chronostratigraphic position of the first truncated brown forest soil in the sections at bockingen bonnigheim and bobingen considered to be the eemian soil or equivalent to oxygen isotope oi substage 5e remains uncertain the methodological results indicate that irsl dating is the more advantageous technique for the upper and middle weichselian periglacial deposits as demonstrated for the loess paleosol sequence in mainz weisenau

glacial dynamics at the beginning of termination i in the eastern alps and their stratigraphic implications abstract results of a geological re investigation of the type localities of the buhl stadial the supposed first halt during ice decay of the inn glacier in the basin of hopfgarten and at the southern flank of the mountain range wilder kaiser northern tyrol austria are presented it is shown that in this region no stationary or advancing inn glacier tongue existed following the last glacial maximum lgm ice extent all sedimentary and morphological evidence indicates that large parts of the inn glacier and all other eastern alpine valley glaciers became stagnant followed by massive down wasting hence this period after the lgm at the beginning of termination i wurm lateglacial is best defined as phase of early lateglacial ice decay which can be tentatively correlated to greenland stadial 2c 21 2 19 5 kyr bp only smaller glaciers advanced towards their lateglacial maximum position lmp this happened mostly due to short lasting climatic oscillations as indicated in the windau valley hopfgarten and at steinach am brenner a mechanically induced glacier advance is reconstructed for the cirque glaciers of the wilder kaiser at an advanced stage of down melting they lost their blockade established by the inn glacier during lgm and advanced downvalley it is proposed to define the processes of this phase by lithostratigraphic type sections

discovery of a landscape wide drape of late glacial aeolian silt in the western northern calcareous alps austria first results and implications abstract aeolian deposits record palaeoenvironmental conditions and may coin soil properties whereas periglacial loess is extensively investigated for 200 years the study of the intramontane wind blown deposits of the alps has just stuttered along herein we describe a drape of polymictic siliciclastic silt interpreted as an aeolian deposit that veneers extensive areas in the western northern calcareous alps nca from kames terraces near valley floors up to last glacial nunataks the nca part of the eastern alps mountain range consist mainly of triassic carbonate rocks these are overlain by deposits of the last glacial maximum lgm and its deglacial paraglacial aftermath e g glacial tills fluvio lacustrine successions alluvial fans scree slopes and a regional drape of polymictic silt newly described herein the drape is typically a few decimeters in thickness and slightly modified by soil formation it consists mainly of well sorted silt of quartz feldspars phyllosilicates muscovite chlorite biotite amphiboles and rarely calcite or dolomite the drape is unrelated to the substrate it overlies carbonate bedrock and in lateral continuity abandoned deposystems such as colluvial slopes of redeposited till kames alluvial fans scree slopes and rock avalanche deposits the drape was spotted from near the present valley floors up to lgm nunataks over a vertical range of some 2000 m it is also present in catchments of the nca that were not overridden by far travelled ice streams and that lack metamorphic rock fragments two osl quartz ages of the drape from two distinct locations 18 77 1 55 ka 17 81 1 68 ka fall into the early alpine late glacial interval shortly after the collapse of pleniglacial ice streams this fits with geological and geomorphological evidence respectively that the drape should be of early late glacial age and that it accumulated during a specific interval of time in the nca localized minor deposition of aeolian dust is documented by other authors from plateaus deglaciated only during the late glacial to holocene no evidence however exists for another phase of similarly widespread aeolian deposition such as that which gave rise to the described regional drape of silt intense aeolian transport and deposition was probably a direct consequence of the liberation of huge amounts of unsorted sediment during deglacial ice collapse perhaps combined with climatic aridification this provides a hitherto unappreciated element of the deglacial to paraglacial phase intramontane dust storms because of its large extent and the availability to osl dating the aeolian drape provides an excellent geochronological marker level identified in terrestrial post glacial successions of the eastern alps because of its fine grained siliciclastic composition the drape gives rise to widespread development of atypical cambisols on carbonate bedrocks with comparatively high water storage capacity and nutrient supply

contemporary glacigenic inputs to the dust cycle the importance of glacigenic dust in the earth s system during glacial periods is widely acknowledged under contemporary conditions the world s largest dust sources are in low lying hot arid regions and this is where most aeolian research is focused however the processes of dust production and emissions are still operating in cold climate regions particularly in proglacial areas this paper assesses current understanding of the relationship between glacierised landscapes and dust emissions and inputs to the global dust cycle it focuses on how elements in the glacial and aeolian geomorphic sub systems interact to determine the magnitude frequency and timing of aeolian dust emissions and on feedback mechanisms between the systems where they have been measured dust emission intensity and deposition rates in glacierised catchments are very high in some cases far exceeding those in lower latitudes however few studies span long time scales the impact of future glacier retreat on the balance between sediment supply availability and aeolian transport capacity and implications for glacigenic dust emissions is also considered this balance depends on relative spatial and temporal changes in meltwater suspended sediment concentration and wind strengths which promote dust emissions and patterns and rates of soil development and vegetation succession on recently deglaciated terrain which protect sediments from deflation retreat of the antarctic ice sheet could mean that in future glacigenic contributions to the dust cycle exceed those of non glacigenic sources in the southern hemisphere copyright 2012 john wiley sons ltd

soil types and eolian dust in high mountainous karst of the northern calcareous alps zugspitzplatt wetterstein mountains germany abstract this study deals with the soil formation on pure limestone in the high mountainous karst of wetterstein mountains northern calcareous alps the study area in detail covers the alpine 2000 to 2350 m and the subnivale zone 2350 to 2600 m of zugspitzplatt a tertiary paleosurface situated next to the highest summit of germany zugspitze 2963 m the formation of autochthonous soils is determined by the following parameters uniform geology and geochemistry of triassic limestone caco3 mgco3 98 variable substrata solid rock debris local moraine hypsometric pattern of vegetation modified by microclimate and aspect variety of micro environments in karst relief in the subnivale zone only leptosols lithic skeletic and regosols calcaric humic occur whereas in the alpine zone different stages of folic histosols and rendzic leptosols prevail due to the diversity of vegetation the purity of limestone prevents a distinct contribution of residues to soil formation instead of expected a b c profiles the residues are mixed with organic matter of folic horizons o ob c only in karst depressions or on local moraines small bt horizons 2 to 5 cm occur they mark a developed stage of folic histosol o ob bt c representing the climax of autochthonous mineral soil genesis in the study area special features are brown deposits mean thickness 30 cm covering large parts of the alpine zone on the basis of mineralogical x ray diffraction heavy minerals and pedological data grain size soil chemistry eolian origin is indicated the resulting soils are classified as loess loam like cambisols ah bw 2 bt 2c and are related to late glacial loess deposition egesen stade of younger dryas the abundance of mica and silt in the surface layers and the grain size distribution of snow dust samples prove that dust influx by southerly winds is still continuing the major sources for both late glacial and present day dust are magmatic and metamorphic rock formations of the central alps additionally local dust transport from adjacent outcrops of jurassic and lower cretaceous sediments is evident

clay mineralogy of a soil sequence in slope deposits derived from hauptdolomit dolomite in the bavarian alps abstract clay mineralogy was determined in a sequence of soils formed in slope deposits derived from hauptdolomit and ranging from a mullrendzina rendoll to a terra fusca eutrochrept and a parabraunerde terra fusca hapludalf results indicated an alteration of illite to hydroxyl al interlayered clay in the course of soil formation no evidence was found of formation of kaolinite in these soils this clearly confirms all soils to have been formed under a recent cold humid climate furthermore clay mineral weathering starts even before carbonates are dissolved and completely removed from these soils

the onset of extensive loess deposition around the g m boundary in china and its palaeoclimatic implications abstract in northern china the red clay loess contact is palaeomagnetically defined at about the gauss matuyama boundary the red clay formation has recently been proposed as mostly of wind blown origin and can be interpreted as having been formed under climatic conditions of continuous warmth punctuated by small amplitude oscillations the shift from red clay development to extensive loess deposition exhibits a 3 fold abrupt increase in aeolian dust deposition rate and marks the beginning of frequent and chaotic climatic fluctuations this event implies a large scale reorganization of the atmospheric circulation over east asia in particular the northward shift and intensification of the siberian high which may have resulted from a dramatic uplift of the tibetan plateau compared to another climatic shift recorded by the chinese loess deposits which occurred at about the upper boundary of the olduvai subchron the red clay loess shift is much more pronounced and recognizable in the field it appears that in regional stratigraphic studies the g m magnetic reversal has a better correlation potential than the upper olduvai

dust transport and palaeoclimate during the oldest dryas in central europe implications from varves lake constance this paper evaluates evidence for seasonal loess deposits in peri alpine lake constance at the end of the last glacial oldest dryas chronozone the usefulness of such lacustrine deposits for palaeoclimatic interpretations is discussed the sedimentology of laminated couplets comprising yellow and grey silts has been investigated to test the hypothesis that the couplets are varves i e annual rhythmites comprising alternations of loess and glacial silt and clay the laminae are mostly less than 1 mm thick and include from bottom to top 1 a matrix of well sorted non graded fine yellow silt with sand size intraclasts 2 coarsening upward grey silt with a cap of fining upward silt to clay the latter is typical for varves in modern proglacial lakes and reflects summer and winter deposits silt and clay respectively we propose that the lack of grading and the matrix supported fabric is indicative of aeolian transport and therefore interpret the yellow laminae as loess deposits volcanic glass intraclasts in the loess layers are probably derived from volcanic terrain to the west of the lake indicating an easterly palaeowind direction deposition of loess in the lake occurred regularly at the beginning of each annual cycle suggesting that the palaeowinds were associated with winter and or spring conditions two transport scenarios are suggested to explain the sand grains scattered in this deep water lacustrine record 1 the grains may have been transported as bedload over the annual winter ice cover of the lake under moderate wind strengths frozen into the ice and released for deposition during spring melt 2 the sand grains were blown directly out onto the lake water by very strong winds during spring the first scenario is contrary to the general view that loess was transported during summer and that loess deposits thus reflect summer conditions only loess input to the lake shows a transitional decrease after ca 14 3 kyr bp and cessation at ca 14 kyr bp probably as a result of a change of wind behaviour increased humidity and or vegetational changes during the oldest dryas in central europe