european glacial dust deposits geochemical constraints on atmospheric dust cycle modeling for a long time global paleodust numerical simulations have greatly underestimated dust sources other than modern deserts recent modeling experiments incorporating glaciogenic sources of dust have positively improved the agreement between model and paleodust data this highlights the importance of accurately representing all areas potentially subjected to deflation during an investigated interval geochemical results obtained from european loess sequences collected along a 50 n transect combined with dust emission simulations reveal the geographical distribution of the most important european dust sources between 34 ka and 18 ka we demonstrate that most european dust traveled only a few hundred kilometers or less within the boundary layer from its source before deposition we conclude that our results encourage acquisition of similar geochemical data for other relevant areas in the world further they could provide critical constraints to benchmark atmospheric models contributing to improve their performance in simulating dust cycle and associated climate feedbacks

paleoclimatic forcing of magnetic susceptibility variations in alaskan loess during the late quaternary visual matches and statistical tests suggest correlations between marine isotope curves retrodictive solar insolation at lat 65 n and magnetic susceptibility profiles through late quaternary age alaskan loess sections the susceptibility changes largely appear to reflect variability in magnetite content due to climatically controlled changes in wind intensity and competence magnetic susceptibility profiles through massive loess can provide stratigraphic context for intercalated paleosols and tephras a prominent paleosol correlated with marine isotope stage 5 occurs several metres above the old crow ash in loess sections indicating that this important tephra is older than suggested by thermoluminescence dates and may have been deposited ca 215 25 ka

out of tune the dangers of aligning proxy archives abstract tuning is a widespread technique to combine date and interpret multiple fossil proxy archives through aligning supposedly synchronous events between the archives the approach will be reviewed by discussing a number of literature examples ranging from peat and tephra layers to orbital tuning and 18o series from marine and ice deposits potential problems will be highlighted such as the dangers of circular reasoning and unrecognised chronological uncertainties and some solutions suggested fossil proxy research could become enhanced if tuning were approached in a more quantitative reliable and objective way and especially if individual proxy archives were non tuned and kept on independent time scales

introducing an improved multi proxy approach for paleoenvironmental reconstruction of loess paleosol archives applied on the late pleistocene nussloch sequence sw germany to study paleoenvironmental and paleoclimatic changes in loess paleosol sequences lps most proxies except for screening parameters have often been applied at low sampling density typically 1 2 per stratigraphic unit this might lead to results that overlook paleovegetation effects that were not only restricted to paleosols but also affected underlying loess material here a new profile was investigated in the loess paleosol sequence lps at nussloch sw germany using a high resolution multi proxy approach to improve our understanding of the late pleistocene record which serves as a standard sequence in central europe this approach included several geophysical and geochemical parameters as well as frequencies of root related features grain size distribution and osl dating enabled correlation of the new section with the nearby standard profile p4 revealing considerable variations of the thickness of stratigraphic units due to local small scale variations in depositional conditions and paleogeomorphology of longitudinal greda structures magnetic susceptibility revealed weathering of the entire lps under more humid conditions than those described for se european and chinese lps it further enabled a rough differentiation between an interval that was influenced by pedogenic processes lower pleniglacial to lower part of the upper pleniglacial and loess that was not markedly affected by soil formation color measurements confirmed these results and enabled the identification of several paleosols in the upper pleniglacial for the uppermost part of the lps low magnetic susceptibility and inorganic geochemical parameters such as low fe ti ratios indicated only weak or no pedogenic influence in contrast considerable variations e g in carbonatic carbon contents and organic carbon nitrogen c n ratio might be related to the high frequency of calcified root remains up to 200 rhizoliths m 2 and up to 12 500 microrhizoliths m 2 in certain depth intervals of the lps entailing incorporation and degradation of organic matter frequencies of biopores which are suggested to derive largely from former root growth and to a lesser extent from insect and earthworm bioturbation were related to paleosols and thus confirmed the pedostratigraphy an improved assessment of terrestrial sedimentary archives can be achieved by high resolution multi proxy analysis and three dimensional investigation of terrestrial sediments that are prone to bioturbation c 2014 elsevier b v all rights reserved

multi proxy dating of holocene maar lakes and pleistocene dry maar sediments in the eifel germany abstract during the last twelve years the elsa project eifel laminated sediment archive at mainz university has drilled a total of about 52 cores from 27 maar lakes and filled in maar basins in the eifel germany dating has been completed for the holocene cores using 6 different methods 210pb and 137cs activities palynostratigraphy event markers varve counting 14c in general the different methods consistently complement one another within error margins event correlation was used for relating typical lithological changes with historically known events such as the two major holocene flood events at 1342 ad and ca 800 bc dating of mis2 mis3 core sections is based on greyscale tuning radiocarbon and osl dating magnetostratigraphy and tephrochronology the lithological changes in the sediment cores demonstrate a sequence of events similar to the north atlantic rapid climate variability of the last glacial cycle the warmest of the mis3 interstadials was gi14 when a forest with abundant spruce covered the eifel area from 55 to 48 ka bp i e during a time when also other climate archives in europe suggested very warm conditions the forest of this early stage 3 warm phase developed subsequently into a steppe with scattered birch and pine and finally into a glacial desert at around 25 ka bp evidence for mono lake and laschamp geomagnetic excursions is found in two long cores several large eruptions during middle and late pleistocene ulmener maar 11 000 varve years bp laacher see 12 900 varve years bp mosenberg volcanoes meerfelder maar 41 45 cal ka bp dumpel maar 116 ka bp glees maar 151 ka bp produced distinct ash layers crucial for inter core and inter site correlations the oldest investigated maar of the eifel is 40ar 39ar dated to the time older than 520 ka bp

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

itrax description and evaluation of a new multi function x ray core scanner a new automated multi function core scanning instrument named itrax has been developed that records optical radiographic and elemental variations from sediment half cores up to 1 8 m long at a resolution as fine as 200 m an intense micro x ray beam focused through a flat capillary waveguide is used to irradiate samples to enable both x radiography and x ray fluorescence xrf analysis data are acquired incrementally by advancing a split core via a programmable stepped motor drive through the flat rectangular section x ray beam traditional xrf determination of element composition in sediments provides high quality data but it takes a considerable time and normally consumes gram quantities of material that is often only available in limited quantities the itrax core scanner non destructively collects optical and x radiographic images and provides high resolution elemental profiles that are invaluable for guiding sample selection for further destructive detailed sampling this paper presents a description of the construction characteristics and capabilities of the itrax system high resolution itrax data obtained from sediment cores are also presented and compared with results from traditional wavelength dispersive xrf analysis at lower resolution finally some recent technical developments linked to the second generation itrax are presented

geochemistry unravels mis 3 2 paleoenvironmental dynamics at the loess paleosol sequence schwalbenberg ii germany abstract the schwalbenberg ii loess paleosol sequence lps denotes a key site for marine isotope stage mis 3 in western europe owing to eight succeeding cambisols which primarily constitute the ahrgau subformation therefore this lps qualifies as a test candidate for the potential of temporal high resolution geochemical data obtained by x ray fluorescence xrf scanning of discrete samples providing a fast and non destructive tool for determining the element composition the geochemical data is first contextualized to existing proxy data such as magnetic susceptibility ms and organic carbon corg and then aggregated to element log ratios characteristic for weathering intensity log ca sr log rb sr log ba sr log rb k and dust provenance log ti zr log ti al log si al generally an interpretation of rock magnetic particles is challenged in western europe where not only magnetic enhancement but also depletion plays a role our data indicates leaching and top soil erosion induced ms depletion at the schwalbenberg ii lps besides weathering log ca sr is susceptible for secondary calcification thus also log rb sr and log ba sr are shown to be influenced by calcification dynamics consequently log rb k seems to be the most suitable weathering index identifying the sinzig soils s1 and s2 as the most pronounced paleosols for this site sinzig soil s3 is enclosed by gelic gleysols and in contrast to s1 and s2 only initially weathered pointing to colder climate conditions also the remagen soils are characterized by subtle to moderate positive excursions in the weathering indices comparing the schwalbenberg ii lps with the nearby eifel lake sediment archive elsa and other more distant german austrian and czech lps while discussing time and climate as limiting factors for pedogenesis we suggest that the lithologically determined paleosols are in situ soil formations the provenance indices document a zr enrichment at the transition from the ahrgau to the hesbaye subformation this is explained by a conceptual model incorporating multiple sediment recycling and sorting effects in eolian and fluvial domains

magnetic susceptibility of loess in china abstract the low field susceptibility of the loess deposits in the chinese loess plateau is due to both paramagnetic and ferromagnetic minerals paramagnetism can be seen in the less to unweathered loess horizons where superparamagnetic contributions which arise from ultrafine magnetite particles are not as strongly developed as in the heavily weathered palaeosols frequency dependent susceptibility and minimum unblocking temperatures of low temperature thermoremanent magnetization generally indicate finer grain sizes in the palaeosols as compared to the loess beds this grain size difference and the fact that susceptibilities of the same stratigraphic palaeosol layer vary by an order of magnitude between the western and central regions of the plateau are considered as strong evidence that the ultrafine magnetite is not of detrital aeolian origin but was formedin situ the pedogenetic processes are clearly related to palaeoclimatic changes therefore the various susceptibility properties may serve for a detailed reconstruction of the continental palaeoclimatic conditions for the last 2 5 ma since the palaeomagnetically dated beginning of loess sedimentation in china

impacts of grain size sorting and chemical weathering on the geochemistry of jingyuan loess in the northwestern chinese loess plateau abstract major and trace elemental compositions of loess samples collected from the jingyuan section in the northwestern chinese loess plateau clp were analyzed to investigate the potential impacts of grain size sorting and chemical weathering on the loess geochemistry and to extract appropriate geochemical indices for better evaluating the east asian monsoon variability based on variations of major and trace elements in different grain size fractions seventeen elements were classified into three types 1 si and na display higher contents with the increased particle sizes 2 al fe mg k mn zn rb cr v are mainly enriched in fine size fractions 3 ti ba zr p ca and sr show irregular variations among different size fractions comparison of al normalized elemental ratios with zr rb and rb sr ratios two commonly employed indicators for grain size sorting and pedogenic weathering indicates that si al zr al ti al variations match well with zr rb and grain size results whilst ca al sr al p al ratios display similar variability as that of rb sr ratio comparison of loess based proxies e g elemental ratios magnetic susceptibility grain size of jingyuan section with speleothem and ice core records confirms that elemental ratios of high resolution loess sequences developed in the northwestern clp can be employed to address fluctuations of the winter monsoon induced grain size sorting and summer monsoon related weathering and pedogenesis at glacial interglacial and millennial timescales

annual accumulation over recent centuries at four sites in central greenland 1 accurate accumulation records are fundamental to understanding mass balance of the greenland ice sheet ice cores can provide multicentury high resolution ground based point estimates of water accumulation in 2003 and 2004 four new ice cores were collected in the central western d4 and d5 and summit sandy and katie regions of greenland annual layer counting based on multiple glaciochemical parameters primarily hydrogen peroxide sea salt and dust proxies was used to date the ice cores resulting in annual dating the bottom depth ages for d4 d5 sandy and katie were estimated at 1738 1673 1844 and 1934 a d with mean annual accumulation rates of 41 4 35 2 22 4 and 22 4 cmweq yr 1 respectively these new records were in good agreement with previous accumulation maps and four previously published records from nearby multicentury ice cores spatial variability was quantified through an analysis of variance thereby allowing for more meaningful comparisons to atmospheric processes more regionally representative accumulation records were constructed for the central western and summit regions spanning recent centuries using a principle component analysis of both the new and previously reported ice core measurements these regional records exhibited 6 7 interannual variability 1 standard deviation of the mean and had lower spatial variability uncertainties than individual accumulation records correlations indicate that 20 of the variance in the central western region was explained by the north atlantic oscillation nao and suggests that an array of more northern ice cores may correlate more closely with nao

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

non magnetic indicators of pedogenesis related to loess magnetic enhancement and depletion examples from the czech republic and southern siberia abstract we carried out a multiparameter investigation for non magnetic proxies of the intensity of pedogenesis in loess paleosol sections from two different climate settings dolni v stonice central europe and krasnogorskoye southern siberia the work was performed in order to clarify the problem of two opposite scenarios of magnetic susceptibility ms patterns in these two profiles the chinese model with magnetically enhanced paleosols and the siberian alaskan model with magnetically depleted paleosols the age constraints on the krasnogorskoye section were inferred from an independent correlation with the well dated dolni v stonice section based on ms and sediment color cie l and with the ms log from lake baikal the pedologic description of the loess paleosol sections and their correlation was considerably improved by the use of vis spectral proxies cie l reflectance in the red band their weathering intensity can be effectively characterized by diffuse reflectance spectroscopy drs and geochemical cec and rb sr proxies whereas the ms is strongly dependent on the type of soil chernozems vs brown soils the geochemical proxies in particular cec proved to be relatively independent of the soil type these parameters are less affected by region specific conditions than the ms signal the non magnetic proxies indicate relatively dissimilar climatic trends at the two sites during the last glacial interglacial cycle a long distance correlation based solely on the ms signal can be adversely affected by switching between the chinese and the siberian alaskan magnetic modes this having been observed at the krasnogorskoye section in general no single universal proxy of weathering or pedogenesis intensity would be applicable across broad regions or considerable climatic gradients paleoclimatologic interpretations of large regions should always be based on a carefully designed multi proxy approach

humid glacials arid interglacials critical thoughts on pedogenesis and paleoclimate based on multi proxy analyses of the loess paleosol sequence crvenka northern serbia abstract loess paleosol sequences lps provide unique terrestrial archives for past environmental and climate changes the loess units are generally interpreted to reflect more arid conditions whereas paleosols are thought to document more humid conditions this paradigm may however deserve to be challenged in some regions because it does not take into account past changes in dust accumulation rates here we present a multi proxy sedimentological and geochemical characterization of the lps crvenka serbia spanning the last 140 ka commonly used analyses such as magnetic susceptibility organic carbon content grain size and weathering indices allow the quantification of the intensity of pedogenesis however loess accumulation rates were much higher during glacials than during interglacials so that it is not trivial to infer past rates of pedogenesis and related paleoclimate conditions novel proxies based for example on lipid biomarkers and their isotopic composition are not so directly affected by changes in loess accumulation rates and might provide interesting new insights long chain plant derived n alkanes in the lps crvenka suggest a minor but non negligible contribution of deciduous trees and shrubs c27 and c29 during mis 1 2 4 and 6 whereas grasses and herbs c31 and c33 dominate the alkane input during mis 3 and 5 this is in agreement with the notion that parts of southeast europe served as refugia for deciduous trees during glacials on the other hand edaphic conditions on the drought prone loess plateaus seem to have been more arid during mis 3 and 5 compound specific d analyses on the alkanes show only little changes on glacial interglacial timescale when compared with the isotopic enrichment of the mediterranean sea during the last glacial this likely indicates a complex combination of reduced temperatures increased rainfall reduced evapotranspiration and more advection of north atlantic moisture although disentangling these factors is difficult interpretation in terms of humid glacials and more arid interglacials seems to be supported also by other novel lipid biomarkers so called gdgts glycerol dialkyl glycerol tetraethers

bromine counts from xrf scanning as an estimate of the marine organic carbon content of sediment cores 1 xrf sediment core scanning technology is increasingly used to quantify sediment composition the overall good correlation between biophilic halogen bromine br and sedimentary total organic carbon toc potentially allows the fast estimation of down core toc profiles by xrf scanning in order to test this approach we present data from the arabian sea and a mediterranean brine basin comparing xrf core scanning br data with discrete sample toc analyses overall br counts and toc show a clear correlation except when stable carbon isotope and c n data indicate intervals characterized by enhanced input of terrestrial organic matter hence solid phase br is exclusively associated with marine organic matter moc and can be used as a direct estimate of this parameter after a calibration is established high pore water br in the brine core steepens the br toc correlation but after salt correction shows a nearly identical gradient to that of the arabian sea core

an environmental magnetic fingerprint of periglacial loess records of late pleistocene loess palaeosol sequences from eastern germany a detailed rock magnetic analysis of the last glacial interglacial loess palaeosol sequences was carried out in the framework of a comprehensive stratigraphic study of loess in saxony eastern germany magnetic susceptibility and laboratory induced remanences have been determined to compare individual sections and to identify the specific rock magnetic characteristics of the saxonian loess province according to the model of pedogenic magnetic enhancement an increasing neoformation of ferrimagnetic minerals in the course of pedogenesis was observed only in the uppermost late weichselian lithological units consisting of pure aeolian loess and indicating dryer climatic conditions in contrast the rock magnetic characteristics of the lower middle and early weichselian units exhibit a significant destruction of primary magnetic minerals caused by such secondary processes as climatically controlled waterlogging and reworking this change in magnetic composition with stratigraphic depth was additionally proved by factor analysis in which the main observation an increasing fd with decreasing argues for a general magnetic depletion in conjunction with decreasing magnetic grain sizes caused by weathering of larger primary particles the magnetic fingerprint of the saxonian loess is characterised by prevailing magnetic depletion processes which effectively rules out the application of the wind vigour model moreover the magnetic characteristics differ significantly from that of other loess regions and support a new and independent model which explains the magnetic behaviour of strongly reworked and waterlogged gleyed loess palaeosol sequences in the relatively humid central european periglacial areas

geochemistry of loess paleosol sediments of kashmir valley india provenance and weathering abstract middle to late pleistocene loess paleosol sediments of kashmir valley india were analyzed for major trace and ree elements in order to determine their chemical composition provenance and intensity of palaeo weathering of the source rocks these sediments are generally enriched with fe 2 o 3 mgo mno tio 2 y ni cu zn th u sc v and co while contents of sio 2 k 2 o na 2 o p 2 o 5 sr nb and hf are lower than the ucc chondrite normalized ree patterns are characterized by moderate enrichment of lrees relatively flat hree pattern gd cn yb cn 1 93 2 31 and lack of prominent negative eu anomaly eu eu 0 73 1 01 average 0 81 paas normalized ree are characterized by slightly higher lree depleted hree and positive eu anomaly various provenance discrimination diagrams reveal that the kashmir loess paleosol sediments are derived from the mixed source rocks suggesting large provenance with variable geological settings which apparently have undergone weak to moderate recycling processes weathering indices such as cia ciw and pia values 71 87 83 83 and 80 57 respectively and a cn k diagram imply weak to moderate weathering of the source material

a new greenland ice core chronology for the last glacial termination 1 we present a new common stratigraphic timescale for the north greenland ice core project ngrip and grip ice cores the timescale covers the period 7 9 14 8 kyr before present and includes the bolling allerod younger dryas and early holocene periods we use a combination of new and previously published data the most prominent being new high resolution continuous flow analysis cfa impurity records from the ngrip ice core several investigators have identified and counted annual layers using a multiparameter approach and the maximum counting error is estimated to be up to 2 in the holocene part and about 3 for the older parts these counting error estimates reflect the number of annual layers that were hard to interpret but not a possible bias in the set of rules used for annual layer identification as the grip and ngrip ice cores are not optimal for annual layer counting in the middle and late holocene the timescale is tied to a prominent volcanic event inside the 8 2 kyr cold event recently dated in the dye 3 ice core to 8236 years before a d 2000 b2k with a maximum counting error of 47 years the new timescale dates the younger dryas preboreal transition to 11 703 b2k which is 100 150 years older than according to the present grip and ngrip timescales the age of the transition matches the gisp2 timescale within a few years but viewed over the entire 7 9 14 8 kyr section there are significant differences between the new timescale and the gisp2 timescale the transition from the glacial into the bolling interstadial is dated to 14 692 b2k the presented timescale is a part of a new greenland ice core chronology common to the dye 3 grip and ngrip ice cores named the greenland ice core chronology 2005 gicc05 the annual layer thicknesses are observed to be log normally distributed with good approximation and compared to the early holocene the mean accumulation rates in the younger dryas and bolling periods are found to be 47 2 and 88 2 respectively

the chronological position of the lohne soil in the nussloch loess section re evaluation for a european loess marker horizon abstract the loess section of nussloch in southwestern germany is a key profile for the reconstruction of the terrestrial palaeo environment of central europe at the time of the last glacial and interglacial recently the significance of the site for palaeo environmental and geoarchaeological research increased additionally with the discovery of unique palaeolithic cultural remains from anatomically and culturally modern humans that invaded southwestern germany during the weichselian wurmian pleniglacial period at nussloch a chrono stratigraphical key position is taken by a middle pleniglacial cambisol remain which under the designation lohne soil serves as an important pedostratigraphic marker horizon for the greater area repeatedly greenland interstadial gis 8 was suggested as a likely period of soil formation for the lohne soil this interpretation is yet not justified on the basis of published chronometric data critical assessment of the data points to a later period of soil formation likely during gis7 to gis5 this conclusion is supported by a new set of radiocarbon ages for the nussloch site which are presented here for the first time consequences of a revised chronology for correlations of pleniglacial cryosols below and above the lohne soil with greenland interstadials are discussed the implications are important for european loess research as the nussloch section serves as a reference base for loess sections throughout europe

late pleistocene landscape dynamics in saxony germany paleoenvironmental reconstruction using loess paleosol sequences abstract loess archives are of paramount importance for reconstructing regional paleoenvironmental conditions of past glacial periods the saxonian loess region is an area of transition between the western and the eastern european loess belt with this contribution a documented loess paleosol composite profile for the saxonian loess region is extended and a new chronostratigraphy established by high resolution osl dating of two profiles is described in addition for the first time osl age estimates for the loess paleosol sequence at seilitz are presented for the quartz and polymineral fine grain fraction based on the presented composite profile climatic and environmental conditions e g wind speed temperature are deduced based on high resolution osl dating it is possible to identify a hiatus spanning ca 30 ka this gap is located in the gleina complex where an underlying layer shows an age of ca 60 ka and the upper layer an age of ca 30 ka additionally two periods of strong loess accumulation with ages of ca 70 60 ka and 30 18 ka could be identified there is a general trend of grain size coarsening up towards the late glacial which shows a maximum at ca 21 ka correlations with french western german and polish loess sections are discussed

influence of the water content on x ray fluorescence core scanning measurements in soft marine sediments the x ray fluorescence xrf core scanner provides bulk sediment chemistry data measured nondestructively at the split core sediment surface although this method is widely accepted there is little known about the effects of physical properties such as density and water content on xrf core scanner data comparison of xrf scanner measurements from the sediment surface and dry powder samples of sediment core geob7920 indicates strongly reduced element intensities for the lighter elements al and si we relate the lower element intensities of the measurements taken at the sediment surface to the amount of water in the sample volume analyzed by the xrf core scanner the heavier elements k ca ti and fe remain relatively unaffected by the variation of any physical property within sediment core geob7920 additionally we successfully use the elemental intensity of cl as a proxy for the seawater content in the sample volume analyzed by the xrf core scanner this enables the establishment of a correction function for the elements al and si that corrects for the radiation absorption of the water content in sediment core geob7920 off cape blanc nw africa

groundwater flow beneath late weichselian glacier ice in nordfjord norway basal water pressure and water flow patterns are significant factors in controlling the behavior of an ice sheet because they influence ice sheet thickness stability and extent water produced by basal melting may infiltrate the subsurface or occur as sheet or channelized flow at the ice bed interface we examine subglacial groundwater conditions along a flowline of the scandinavian ice sheet through nordfjord in the western fjords region of southern norway using a steady state two dimensional groundwater flow model meltwater input to the groundwater model is calculated by a two dimensional time dependent thermomechanically coupled ice flow model oriented along the same flowline model results show that the subglacial sediments could not have transmitted all the meltwater out of the fjord during times of ice advance and when the ice sheet was at its maximum position at the edge of the continental shelf in order for pore water pressures to remain below the overburden pressure of the overlying ice other paths of subglacial drainage are necessary to remove excess water during times of retreat the subglacial aquifer is incapable of transmitting all the meltwater that was probably generated pulses of meltwater reaching the bed could explain non climatically driven margin readvances during the overall retreat phase

zr rb ratio in the chinese loess sequences and its implication for changes in the east asian winter monsoon strength abstract the long term dust accumulation sequences on the chinese loess plateau clp provide a valuable opportunity to study the evolution of east asian winter monsoon strength grain size of bulk samples of loess deposits though widely used is a modified measure of the strength of winter monsoon wind due to modification by post depositional weathering and pedogenesis this study proposes a new and reliable geochemical climate proxy that records the variability of the east asian winter monsoon on the clp six loess paleosol sections on the plateau were selected for measuring concentrations of the trace elements zr and rb as well as grain size variations of the zr rb ratio in all the sections encompassing the last 130 ka display a generally similar pattern to that of mean grain size of bulk samples mgsb though a positive correlation exists between the zr rb ratio and mgsb the correlation coefficient decreases in southern and eastern sections where intense pedogenesis occurred in the relatively warm and humid climates long term zr rb variation in the lingtai section exhibits amplitudes and frequencies similar to those in mgsb and the mean grain size of quartz particles mgsq accepted as a more reliable proxy than mgsb in the upper loess paleosol sequence over the past 2 6 ma however for the underlying red clay formation in the interval from about 7 2 6 ma b p the mgsb record is relatively stable whereas both the zr rb ratio and mgsq show distinct variability and display amplitudes similar to those observed in the overlying loess paleosol sequence these results demonstrate that the zr rb ratio reflects original eolian grain size and may serve as a reliable index of the strength of east asian winter monsoon winds

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

luminescence and amino acid racemization chronology of the loess paleosol sequence at suttő hungary abstract the loess paleosol sequences in hungary provide an excellent upper pleistocene climate archive of the carpathian basin loess deposits up to 20 m thick cover the sutt travertine complex located in the very northern part of hungary next to the right bank of the danube river the loess is intercalated with two weakly developed greyish horizons two thinner brownish steppe like soils and a pedocomplex including a reddish brown clay enriched horizon covered by a chernozem like paleosol infrared optically stimulated luminescence irsl dating was applied on polymineral fine grain material to determine the depositional age of the loess the uppermost loess yields irsl age estimates ranging from 15 to 40 ka the loess on top of the pedocomplex yields irsl age estimates ranging from 48 to 60 ka the pedocomplex most likely correlates with the marine oxygen isotope stage mis 5 interglacial period the loess from below the pedocomplex was deposited during the penultimate glaciation as evidenced by amino acid racemization aar results further independent age control is provided by radiocarbon dating for the upper part of the profile and by uranium series 230th 234u ages correlating the travertine below the loess with mis 7 8 the magnetic susceptibility record through the sequence shows a strong correlation with the loess layers and soil horizons