site specific variability of loess and palaeosols ruma vojvodina northern serbia abstract the study of temporal variations in soil intensity has mostly been limited to specific sites however it is important for correctly interpreting the stratigraphy and palaeoclimatic significance of loess and palaeosols series to understand the reasons for the spatial variability more specifically pedogenetic and sedimentological properties should be evaluated separately this is particularly well illustrated at the ruma site serbia in this paper we focus on macroscopic soil characteristics and sediment grain size properties the type succession shows three interglacial pedocomplexes v s1 v s2 and v s3 separated by loess layers that include at least one interstadial pedocomplex in the uppermost loess layer all sediments show a bipartite grain size distribution a coarser grained silt dominated one and a fine grained one

functional soil landscape modelling to estimate slope stability in a steep andean mountain forest region abstract landslides are a common phenomenon within the ecuadorian andes and have an impact on soil landscape formation landslide susceptibility was determined in a steep mountain forest region in southern ecuador soil mechanical and hydrological properties in addition to terrain steepness were hypothesised to be the major factors in causing soil slides hence the factor of safety fs was calculated as the soil shear ratio that is necessary to maintain the critical state equilibrium on a potential sliding surface regression tree rt and random forest rf models were compared in their predictive force to regionalise the depth of the failure plane and soil bulk density based on terrain parameters the depth of the failure plane was assumed at the lower boundary of the stagnic soil layer or soil depth respectively depending on soils being stagnic or non stagnic fs was determined in dependence of soil wetness referring to 0 001 0 01 0 1 and 3 mm h 1 net rainfall rates sites with fs 1 at 3 mm h 1 complete saturation were classified as unconditionally stable sites with fs 1 as unconditionally unstable bulk density and the depth of the failure plane were regionalised with rf which performed better than rt terrain parameters explained the spatial distribution of soil bulk density and the depth of the failure plane only to a relatively small extent which is reasonable due to frequent translocation of soil material by landslides nevertheless their prediction uncertainty still allowed for a reasonable prediction of unconditionally unstable sites

geological hazards in loess terrain with particular reference to the loess regions of china abstract the considerable morphodynamic energy provided by the continuing tectonic evolution of asia is expressed in high erosional potentials and very high rates of sediment production that make this continent unequalled as a terrestrial source of primary silt many of these environments are hazardous threatening human occupation health and livelihood especially in regions of dense population such as the loess lands of north china dry loess can sustain nearly vertical slopes being perennially under saturated however when locally saturated it disaggregates instantaneously such hydrocompaction is a key process in many slope failures made worse by an underlying mountainous terrain of low porosity rocks gully erosion of loess may yield very high sediment concentrations 60 by weight characteristic vertical jointing in loess influences the hydrology enlarged joints develop into natural sub surface piping systems which on collapse produce a loess karst terrain collapsible loess up to 20 m thick is common on the western loess plateau foundation collapse and cracked walls are common many rapid events following periods of unusually heavy monsoonal rain slope failure is a major engineering problem in thick loess terrain flow slide and spread types being common the results are often devastating in both urban and rural areas an associated hazard is the damming of streams by landslides the human population increases the landslide risk in china notably through imprudent land use practices including careless water management a number of environmentally related endemic diseases arise from the geochemistry of loess and its groundwaters including fluorosis cretinism kaschin beck disease keshan disease and goitre the chinese desert margins also have a major atmospheric dust problem the effect of such dust upon human health in these extensive regions including many large cities has yet to be evaluated but pneumoconiosis is thought to affect several million people in north and west china

stacked 2 6 ma grain size record from the chinese loess based on five sections and correlation with the deep sea δ18o record 1 this study aims to establish a stacked climate record of the quaternary period from the chinese loess sequence and to address the forcing mechanisms for the regional climate history of the loess plateau by correlating the stacked record with a composite 18o record in deep sea sediments a total of 18 352 samples were obtained from five loess sections located at baoji lingtai jingchuan puxian and pingliang in the southern and middle loess plateau these yielded high resolution grain size records between section correlation of these shows that although small depositional hiatuses are present in places within a single section most parts of the sections display near continuous dust deposition throughout the quaternary the grain size records were tuned simultaneously to the theoretical variations in obliquity and precession of the earth s orbit the grain size records plotted on their orbital timescales were then averaged to form a stacked loess grain size time series termed the chiloparts record this resolves most of the orbital timescale paleoclimate events buried in the loess soil sequences of the southern and middle loess plateau and can be used as a regional archive of the pleistocene climate history in the loess plateau comparison of the chiloparts record with a composite marine 18o record shows that for the past 1 8 ma the loess paleosol record can be correlated almost cycle by cycle with the marine record several discrepancies in the climatic events between the two records have also been identified implying that regional forcing mechanisms may have played a part in the climatic evolution of the chinese loess plateau

loess and bee eaters ii the loess of north africa and the nesting behaviour of the northern carmine bee eater merops nubicus gmelin 1788 abstract the northern carmine bee eater merops nubicus lives and breeds in a well demarcated region stretching across africa close to the 15 n line of latitude the bee eater zone appears to be associated with a band of loess defined by scheidig on his 1934 map as second order loess bee eaters are known to favour loess for nesting tunnels and it appears that the 15 n material is sufficiently loess like obvious sources for particulate materials for the 15 n band are the fonta djalon highlands which supply sedimentary material to the river niger the bodele depression the deepest part of lake megachad source of dust for the world the ethiopian highlands at the eastern end of 15 n which supply silt to the nile system and particulates to the 15 n region in soil moisture terms the region is ustic which is possibly a necessary condition for bee eater nests the clastic material requires an ustic environment the river niger can be seen as a loess river in some senses a mirror image of a major loess river like the danube but where a restricted range of particle inputs leads to a restricted range of loess deposit outputs nevertheless loess river considerations can be applied the niger delivers second order loess and an important loessic admixture to the landscape enough loess for selective nesters like the carmine bee eaters to build their nest tunnels in it it seems likely that climate change will cause a change in bee eater distribution it seems unlikely that they will abandon their nesting regions the living and wintering zones may shift

late cenozoic fluvial lacustrine susceptibility increases in the linxia basin and their implications for tibetan plateau uplift the variations and mechanisms of fluvial lacustrine mass specific magnetic susceptibility in the northeastern ne tibetan plateau are complex in this study we compiled two miocene pliocene records the heilinding and maogou sections respectively from the linxia basin fluvial lacustrine sediments ne tibetan plateau to describe the increases and discuss their influential factors the in the heilinding section remained relatively stable at low values before ca 8 5 ma and has increased since ca 8 5 ma with strong fluctuations in the maogou section the increased at ca 6 0 ma with relatively weak fluctuations the mean values were higher in the heilinding section than the maogou section the rock magnetic results showed that hematite dominated both sites during the early periods 8 5 ma in the heilinding and 6 0 ma in the maogou respectively and was replaced by magnetite after that time based on the comparison of records in linxia basin with other magnetic and climate records from the surrounding regions the increase around 8 5 6 0 ma in the linxia basin was mainly driven by tectonics in the northeastern tibetan plateau

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

elevated temperature irsl dating of loess sections in the east eifel region of germany abstract it has been shown that the infrared stimulated luminescence signals measured at elevated temperature after an ir stimulation at 50 c post ir irsl are significantly more stable than the conventional irsl at 50 c ir 50 in this study a post ir irsl protocol using a second ir stimulation temperature of 290 c pirir 290 was applied to 17 polymineral fine grain 4 11 m samples from various loess sections in the eifel region wannenkopfe dachsbusch karlich and ariendorf with independent age control to test the reliability of ages using the pirir 290 signal the laboratory measured fading rates are below 1 decade on average for the pirir 290 both ir 50 and pirir 290 signals of 9 samples were found to be in field saturation the average ratio of the sensitivity corrected natural signal to the laboratory saturation level for the pirir 290 is 0 98 0 02 n 9 showing that field saturation is equal to laboratory saturation for the pirir 290 signal from polymineral fine grains from the eifel region minimum equivalent dose estimates were calculated from the characteristic saturation dose of the dose response curves giving minimum ages estimates of 230 420 ka and suggesting that the pirir 290 signal can be used to date loess to 300 ka the pirir 290 ages estimates of the samples from the wannenkopfe and dachsbusch sites are in good agreement with independent age control showing that the irsl dating using pirir 290 signal without fading correction is apparently reliable our data suggest that the loess units e f g and the lower part of h at the karlich site were accumulated 270 ka and that the palaeosol of the karlich interglacial i most likely developed during marine isotope stage mis 9 or earlier the pedocomplex on the top of loess bed ii at the ariendorf section can be correlated with mis 7

spatial patterns of vegetation and climate on the chinese loess plateau since the last glacial maximum abstract in order to identify the spatial patterns of vegetation and climate on the chinese loess plateau since the last glacial maximum lgm pollen analysis was conducted for loess deposits from seven sites which constitute two north south and west east transects across the plateau results show that steppe prevailed both in the lgm and the holocene optimum during the lgm vegetation in the northwest mainly consisted of artemisia echinops type taraxacum type and chenopodiaceae and vegetation in the southeast was characterized by the same types but with a slight increase in poaceae during the holocene optimum vegetation was more diverse with poaceae artemisia echinops type and chenopodiaceae dominant in the northwest and pinus corylus poaceae artemisia and selaginella sinensis dominant in the southeast our records also show that from the lgm to the holocene optimum the presence of echinops type and taraxacum type pollen decreased while poaceae pollen became more prevalent as it has been found that most species of poaceae prefer relatively humid conditions and abundances of echinops type and taraxacum type increase in desert vegetation a new proxy poaceae echinops type taraxacum type ratio p e t was thus developed to compare the spatial differences in climate between the lgm and the holocene optimum with high p e t values indicating relatively warm and wet conditions the p e t ratio shows an overall southward and eastward increase for both the lgm and the holocene optimum furthermore it exhibits a prominent north south and west east gradient during the holocene optimum but displays a flat one during the lgm indicating more pronounced spatial contrasts in climate during the holocene than in the lgm this phenomenon may be attributed to the unique geographic location of the loess plateau which was located in the marginal zone of the east asian summer monsoon during interglacials but was dominated by the winter monsoon during glacials due to a southward displacement of climate zones

soil properties on a chronosequence of landslides in montane rain forest ecuador to assess the impact of landslides on soil fertility in south ecuador we compared the properties of shallow translational debris slides with those of adjacent undisturbed soils a chronosequence of four small landslides ca 0 5 ca 2 3 ca 8 10 and ca 20 years old was selected on a 30 50 forest covered east facing slope of the eastern cordillera at 1900 2300 m above sea level a s l all soils were dystric cambisols the mean mass of the soil organic layer sum of all o horizons increased in the order landslide head 46 t ha 1 central part track 101 t ha 1 foot 102 t ha 1 reference soils 291 t ha 1 implying a variation in nutrient storage of the same order in the head area only the oldest landslide had an organic layer all mineral soils were acidic ph in h2o of the a horizon 3 4 5 2 the effective cec of the a horizon ranged from 22 to 141 mmolc kg 1 and the base saturation from 13 to 54 none of these properties was consistently different between landslide and reference soils the a horizons of the soil in the landslide foot area had greater concentrations of most nutrients than those in the landslide head area however differences were not significant the nutrient concentrations in the landslide foot area resembled those in the a horizons of the reference soils thus the most obvious change in soil properties caused by the landsliding was partial or complete removal of the organic layer which was not restored during the ca 20 years covered by the chronosequence this decreased the topsoil fertility of the landslide area

improving soil hydromorphy prediction according to dem resolution and available pedological data abstract this study analyses the sensitivity of soil hydromorphy prediction methods with regard to the resolution of topographical information and additional soil data seven digital elevation models dem were computed and compared to topographic measurements with different resolutions 10 20 30 and 50 m and construction mode inputting actual stream location in addition to contour lines prediction models of soil hydromorphy using linear regression and co kriging were established from detailed descriptions of soil catenas and topographical investigations on a 2 ha site these models were compared on a validation set the dems with fine resolutions from 10 to 30 m estimated in a unbiased way the elevation e the elevation above the stream bank es the downslope gradient dg and the upslope contributing area amu whereas prediction errors increased for the lower resolution 50 m dems apparently the location of the channel network had no systematic effect on the estimation errors there was a strong relationship between soil hydromorphy index hi and es r 2 0 80 and the compound topographic index cti ln amu dg r 2 0 62 for dem resolutions of less than 30 m soil hydromorphy prediction models bound on a regression model with topographic attributes appeared efficient and even better than ordinary kriging or with 10 or 60 point observations coarser dem resolutions 30 and 50 m highly deteriorated prediction quality for these resolutions quality of soil hydromorphy prediction was highly improved by co kriging of 10 and especially 60 pedological data points with a topographical regression model

diversity of diagnostic horizons in soils of the contiguous usa a case study abstract many previous studies of pedodiversity have emphasized the lateral variability of soils in this study the vertical distribution of diagnostic horizons is examined at the soil series level unlike genetic horizons diagnostic soil horizons are based on quantitatively defined morphological and analytical properties and they form the basis of modern soil classification systems an examination of 1600 soil series in 63 representative out of 226 major land resource areas mlras in contiguous usa revealed that they contain from one to seven diagnostic soil horizons with an average of 2 6 1 2 about 20 of the soil series contain 4 or more diagnostic horizons 80 of these soil series are in seven great groups the glossudalfs haplorthods fragiorthods endoaquods epiaquods fraglossudalfs and glossaqualfs the laurentide great lakes region contains a discordant number 57 of soils with 4 or more diagnostic horizons the most common being ochric 100 albic 91 argillic 85 glossic 69 spodic 51 and a fragipan 19 several factors appear to contribute to the diversity of diagnostic horizons including proximity to the great lakes where abundant snowfall precludes soil freezing and enables water to percolate rapidly through the soil in a short interval during the spring the prevalence of stratified glacial deposits often containing a lithologic discontinuity and a fluctuating water table all of which enable specific weathering products to accumulate at different depths

the late pleistocene belotinac section southern serbia at the southern limit of the european loess belt environmental and climate reconstruction using grain size and stable c and n isotopes the belotinac loess section is one of the southernmost loess paleosol environmental archives for the late quaternary in serbia the climate at this site is intermediate between the continental and the mediterranean realms which makes this loess archive potentially highly sensitive to past climatic changes this paper presents new insights into the paleoenvironmental history during the last glacial period in southern serbia using grain size and isotope proxy data the grain size parameters from the belotinac section reveal variations in the paleowind dynamics and weathering intensity and suggest the nearby valley of the ju na morava river as an important source of aeolian sediments in this area based on a multiproxy dataset alternating phases of weak interstadials and phases of enhanced loess deposition at this site were identified nitrogen isotope data suggest that during marine isotope stage 3 ecosystems of high biomass productivity and rather open n cycles prevailed during marine isotope stage 2 productivity was reduced and the n cycle was more strongly closed probably due to a shorter growing season and more pronounced temperature decline carbon isotope data indicate a possible contribution of c4 plants to the holocene vegetation but not to the glacial and interstadial ecosystems of the late pleistocene changes in atmospheric co2 level are not reflected in the carbon isotope record these findings are discussed in the light of paleoclimate proxy datasets from the morava river valley and carpathian basin as well as through comparison of carbon isotope records from loess sections in se central europe and in the rhine valley two different loess provinces exist in terms of glacial interglacial humidity changes a province of glacial drying and a province of glacial humidification the first includes loess sites under more oceanic influence where loess 13c records indicate humid interglacials and interstadials and relatively drier glacial periods the second includes the loess sites of the carpathian basin and especially the southern serbian loess area of belotinac where loess 13c records indicate more intensive aridity during interglacials but a reduced soil moisture deficit and a more humid climate due to lower evapotranspiration in interstadials and even more in glacial periods

identification of the spatial distribution of soils using a process based terrain characterization abstract a simple process based terrain characterization model was developed to identify the occurrence of soils over a complex landscape its basic proposition is that soil distribution can be most efficiently identified by the separation of pedogeomorphological units where similar hydrological geomorphological and pedological processes occur the proposed model is a three dimensional extension of the nine unit soil landscape model the two dimensional conceptual and qualitative model is reinterpreted in terms of continuity equations describing the distribution of soil materials over hillslopes and is implemented in a geographical information system gis through the analysis of a raster digital elevation model dem the application of this model at the empire prairie in southern wisconsin usa shows a good agreement with the results of a soil investigation the difficulty in modeling the diverse geomorphological and pedological processes at low lying slope positions and the influence of relict pedological features on contemporary soil formation however remain unsolved this model can consider the spatial variability of soils both at the continuous and discrete scales and is easily transferable to other slopes in a predictive manner it is further expected to provide a quantitative tool to characterize surface topography in terms of process identification and resource survey and also a priori information for spatially distributed ecological and environmental models

geochemical evidence of the sources of aeolian sands and their transport pathways in the minqin oasis northwestern china identification of aeolian sand sources occurring in oases of desert environments is of great importance for understanding desertification processes and for developing strategies for sustainable development in arid regions combined with wind data and hierarchical cluster analysis we analyzed the spatial characteristics of major and trace elements of sands sampled at the margins of the minqin oasis northwestern china and its adjacent deserts the badain jaran desert and the tengger desert with the purpose to identify the aeolian sand sources and their transport pathways in the region the spatial distribution revealed by bivariate plots of cr ni cr v y ni al v zr hf zr hf and ternary plots of major and trace elements showed that sands between the west b badain jaran desert bm the dune belt between badain jaran and the minqin oasis and tne dune field located in the northeast margin of the minqin oasis and southeast tsw dune field located in the southeast margin of the minqin oasis sides of the oasis have different provenances while the composition of sands in the minqin oasis m and in the dune field located in the south margin tm is associated with both the variations in abundance of k rb ba and sr were used as indicators of aeolian transport processes our results show that while aeolian sands from the badain jaran desert can be transported over mountains and over long distances by northwest winds to the west sides of the minqin oasis they cannot directly reach neither bypass the oasis to the east side our interpretation is that the oasis can act as an effective barrier to stop the migration of dune fields both in the badain jaran desert and the tengger desert however the extensive occurrence of aeolian sands in the minqin oasis indicates that its role in preventing desert encroachment should not be overestimated c 2014 elsevier ltd and inqua all rights reserved

palaeoenvironment and geoconservation of mammoths from the nosak loess palaeosol sequence drmno northeastern serbia initial results and perspectives a quaternary site at drmno comprising of middle and late pleistocene loess palaeosol sequences near kostolac northeast serbia attracted attention from the general public and scientists when several steppe mammoth and other mammal skeletons from middle pleistocene fluvial deposits were discovered in 2009 and 2012 this paper presents the combination of malacological and enviromagnetic analyses preliminary luminescence dating litho pedostratigraphic and palaeo relief investigations that were applied to the nosak loess palaeosol sequence for the 2012 findings the results confirm and emphasize the antiquity of the sediments preserved in the nosak section and demonstrate the significance of the detailed and relatively complete palaeoenvironmental record they contain these discoveries can significantly contribute to setting the background towards an improved understanding of the evolution of mammoths on the european continent

karl caesar von leonhard 1779 1862 and the beginnings of loess research in the rhine valley abstract the term loess entered the scientific vocabulary in 1824 in section 89 of charakteristik der felsarten by karl caesar von leonhard a two page definition and description plus details of a few locations the term had been used before 1824 but leonhard places it firmly into the literature there were alternatives leonhard made a choice interest in loess developed in the early 1820s perhaps in association with interest in the geology of the rhine volcanoes possibly the first fairly detailed study of loess was by h g bronn in 1830 after 1830 hibbert horner and lyell carried forward the study appreciation of loess in english charles lyell in principles of geology listed ten pioneers bronn leonhard boue voltz noeggerath steininger merian rozet von meyer and hibbert early ideas of loess formation emphasized the role of deposition from water perhaps influenced by the advocacy of boue for continent wide inundations leonhard was an important figure and deserves his position as the most significant loess pioneer lyell was largely responsible for the spread of interest in loess via the principles of geology

making use of the world reference base diagnostic horizons for the systematic description of the soil continuum application to the tropical mountain soil landscape of southern ecuador abstract the world reference base for soil resources wrb fao iuss working group wrb 2007 at present does not acknowledge the spatial soil continuum but provides a sound basis to do so using methods from statistical learning theory to develop digital soil maps is much more efficient and precise while regionalising soil diagnostic properties instead of complex entities such as the soil units assigned by the wrb particularly in providing spatial soil information displayed in digital soil maps any aggregation of this spatial soil information to soil units means a loss of information the soil landscape can be systematically described in its spatial continuum simply by the vertical order and extent of the wrb diagnostic horizons the diagnostic horizons are related in their thickness to a standard depth and listed from top to bottom in order of appearance typical diagnostic horizon thickness and occurrence probability were predicted from terrain parameters by classification and regression trees cart throughout the research area in southern ecuador the two disadvantages of cart abrupt prediction class boundaries and dependence on the dataset were addressed by hundredfold model runs on different data subsets leading to a range of possible predictions prediction uncertainty was included in the digital soil maps by calculating these predictions means and standard deviations as well as by horizon occurrence probability prediction model performance was evaluated by means of hundredfold external cross validation terrain parameters were found to have a strong influence on diagnostic topsoil properties however no influence on the vertical profile differentiation was observed hence predicting horizon thickness and subsoil diagnostic properties was difficult the systematic description of the soil continuum of this particular soil landscape resulted in histic and stagnic soil parts dominating the first 100 cm of the soil column for most of the area

middle and late pleistocene loess sequences at batajnica vojvodina serbia abstract loess sequences in the vojvodina region northern serbia reveal a continuous record of paleoclimatic variations during the middle and late pleistocene the most detailed stratigraphic information comes from remarkable exposures on the cliffs of the right danube bank from vukovar to belgrade the batajnica loess section has been recognized as one of the most complete middle and late pleistocene records in this region a more than 40 m thick loess paleosol succession represents environmental transition from relative thin loess layers and rubified soils in lower part of profile to thick loess and fossil chernozems characterizing the last three glacial interglacial cycles the proposed stratigraphic model is based on a detailed magnetic susceptibility ms record which is related to the deep sea isotope stratigraphy and on correlation with other eurasian loess records using the distinct ms pattern of selected loess paleosol couplets this new stratigraphic model suggests serious revision of previous chronological interpretations ms as function of depth shows a well known pattern of low values in loess and high values in paleosols indicating strong enhancement of magnetic minerals during soil formation with the exception of the recent soil v s0 which is strongly contaminated by archaeological artifacts the third paleosol v s3 reveals the highest values in ms and a very distinct double peak the rock magnetic signal at batajnica resembles the typical pattern of the enviromagnetic records determined from other eurasian loess sites the paleopedological interpretations rubification index values and rock magnetic record at batajnica yield valuable data for the reconstruction of paleoclimatic fluctuations for the last 5 glacial interglacial cycles at least moreover the record provides an important link between the classical central european loess sites and the central asian and chinese loess provinces

variations in loess and palaeosol properties as indicators of palaeoclimatic gradients across the loess plateau of north china abstract new data are presented on micromorphology magnetic susceptibility and particle size characteristics of three soil sediment units at four locations along a wnw ese transect across the loess plateau of north china differences and spatial trends are used to assess the sensitivity of such data as proxies of regional palaeoclimatic gradients the steepest climatic gradient suggested by the magnetic susceptibility for the s1 palaeosol is at the eastern humid end of the traverse micromorphology and particle size analysis show that the loess units in the east are richer in clay than the best developed palaeosols in the semi arid west and that particle size in the west appears to provide a more sensitive record of climatically driven changes than magnetic susceptibility the use of surface and near surface soils as a datum for inferring palaeoprecipitation values is reviewed in the light of recent evidence of substantial degradation of such soils micromorphological and particle size analysis of closely spaced samples from loess palaeosol sequences is a sensitive addition to magnetic susceptibility stratigraphy and correlation

quantitative relationships between magnetic enhancement of modern soils and climatic variables over the chinese loess plateau environmental magnetism has been widely employed to reconstruct past climate changes on the chinese loess plateau clp and several climofunctions based on the magnetic properties of loess have been developed however systematic investigation of the quantitative relationship between topsoil magnetic enhancement and modern climate remains uncommon in this study we obtained surface soil samples from 257 sites over the clp and adjacent regions from this set we used 180 samples from sites unaffected by potential contamination to investigate the relationship between the commonly measured magnetic properties of magnetic susceptibility and magnetic remanence and modern climatic variables the spatial distribution of the results demonstrates a strong nw se gradient of the magnetic enhancement of surface soils the results of more detailed magnetic parameters indicate that pedogenic viscous superparamagnetic and stable single domain particles are mainly responsible for the magnetic enhancement of the soils in the studied region and that the magnetic grain size distribution of the ferrimagnetic components of pedogenic origin remains almost constant independent of pedogenic intensity the uniform mechanism of magnetic enhancement mainly linked with the concentration of the pedogenic components rather than with variations in magnetic grain size decreases the level of ambiguity in climate reconstructions based on magnetic measurements of chinese loess statistical analyses including correlation principal component analysis pca and multiple regression analysis suggest that annual rainfall rather than temperature exerts the dominant effect on soil magnetic enhancement finally we used the results to develop several transfer functions to reconstruct mean annual precipitation map transfer functions based on frequency dependent susceptibility fd and anhysteretic remanent magnetization arm provide the most reliable estimates of map this study significantly improves the understanding of the relationship between soil magnetic properties and climate

palaeosol development in the chinese loess plateau as an indicator of the strength of the east asian summer monsoon evidence for a mid holocene maximum the interpretation of the stalagmite delta o 18 record from southern china as an indicator of east asian summer monsoon easm rainfall amount or intensity is strongly debated soil development in the chinese loess plateau clp situated in the modern summer monsoon domain has long been treated as a direct and reliable easm proxy in this study we compiled 81 loess and 229 palaeosol dates from 77 profiles across the clp and synthesized the data statistically in order to investigate the easm history during the holocene the resulting history of holocene loess deposition and palaeosol development demonstrates that 1 loess deposition decreased and palaeosol formation increased across the clp after 11 5 ka 1 ka 1000 cal yr bp revealing a gradually intensified easm during the early holocene 2 numerous palaeosols developed in the clp between 8 8 ka and 3 4 ka indicating a generally strong easm during the mid holocene 3 the number of palaeosol dates decreased rapidly at around 3 ka suggesting a sudden retreat of the easm in the late holocene these trends of easm evolution are broadly consistent with variations in aeolian sand activity in the four main sandlands the mu us otindag horqin and hulun buir sandlands along the modern monsoon fringe in northern china and are supported by a wide range of independent evidence in addition we also found that high loess deposition and stronger aeolian activity occurred at similar to 5 ka representing a weak easm event within the context of an overall strong mid holocene easm the strong mid holocene easm revealed by palaeosol development in the clp and aeolian sand activity in the sandlands in northern china contrasts with the early holocene easm maximum suggested by stalagmite delta o 18 data from southern china our results are compatible with the proposal that the stalagmite delta o 18 variations in china do not result from changes in easm rainfall amount or intensity but instead reflect changes in moisture source driven by variations in atmospheric oceanic circulation c 2014 elsevier ltd and inqua all rights reserved