Loess Paleosol Research Articles

A 220 ka terrestrial δ18O and deuterium excess biomarker record from an eolian permafrost paleosol sequence, NE-Siberia

The natural abundances of stable oxygen (18O/16O) and hydrogen isotopes (2H/1H) are valuable proxies of climate changes in the past. Yet, to date no continuous δ18O and only few δ2H records are available from loess–paleosol sequences. Taking advantage of a recently developed method based on compound-specific δ18O analyses of hemicellulose sugar biomarkers in soils (Zech and Glaser, 2009. RCM 23, 3522-3532), we here present a first terrestrial δ18O biomarker record from an eolian permafrost paleosol sequence in NE-Siberia that covers the last ~220ka.The δ18O values of the hemicellulose biomarkers arabinose and xylose range from 22.5 to 32.8‰ and from 21.3 to 31.9‰, respectively, and reveal systematic glacial–interglacial shifts. The modern topsoil and the interglacial paleosols exhibit more positive δ18O values, whereas the glacial paleosols are characterized by more negative δ18O values. This is in agreement with the δ2H record obtained for sedimentary n-alkane leaf wax biomarkers. We present a conceptual model for interpreting the combined δ18O and δ2H biomarker record. Based on this model, we suggest that both our δ18O and the δ2H records primarily reflect the temperature-controlled isotopic composition of paleoprecipitation modified by evaporative isotope enrichment of leaf water during transpiration.Considering fractionation factors during sugar and n-alkane biomarker biosynthesis allows reconstructing the leaf water isotopic composition and the deuterium excess of the leaf water. The deuterium excess may serve as proxy for evaporative enrichment and allows calculating relative humidity using a Craig–Gordon model. Accordingly, relative humidity in NE-Siberia was higher during marine isotope stage (MIS) 6 compared to MIS 2, 4 and 5d and thus could help explaining the much larger extent of the Late Saalian glaciation compared to the Weichselian glaciations.Using the Craig–Gordon model, we also calculated δ18O of the plant source water (δ18Osource water), which can be assumed to primarily reflect δ18O of paleoprecipitation. Our 220ka δ18Osource water record is well in agreement with the δ18Odiatom record from Crater Lake El'gygytgyn in NE-Siberia and enables a regional paleoclimate reconstruction and interpretation. Accordingly, summer temperature was periodically warmer than at present during the Weichselian glacial period and there is a strong July insolation forcing of the summer temperature in the extremely continental study area. Overall, our study highlights the great potential of the novel hemicellulose biomarker δ18O method for paleoclimate reconstructions, especially when combined with δ2H analyses of n-alkane lipid biomarkers.

Tectonic controls for transverse drainage and timing of the Xin-Ding paleolake breach in the upper reach of the Hutuo River, north China

The upper reach of the Hutuo River flows along the Xin-Ding basin and cuts a transverse drainage through the Xizhou Mountain and the Taihang Range into the North China Plain. Previous studies showed that the Xin-Ding basin was occupied by a lake during the early-middle Pleistocene. However, the timing of the paleolake breach and the mechanism for the creation of the transverse drainage are unknown. We constructed the fluvial terrace sequence in the upper reach of the Hutuo drainage combined with thermoluminescence (TL) and optically stimulated luminescence (OSL) dating, as well as the timescale of the overlying loess–paleosol sequence. Our results reveal that (1) five terraces (T5–T1) developed along the upper reach of the Hutuo River, amongst which terraces T4–T1 were formed synchronously at ~600, ~120–130, ~20–26 and ~6–7ka, respectively; (2) the creation of the transverse drainage and breach of the Xin-Ding paleolake occurred between ~600 and ~130ka; and (3) the mechanism for the creation of the transverse drainage is via river piracy of paleostreams on both sides of the drainage divide. Localized differential uplift and associated tilting of the Xizhou Mountain block during the middle Pleistocene result in the formation of the transverse drainage and breach of the Xin-Ding paleolake.

Deposition and weathering of Asian dust in Paleolithic sites, Korea

Paleolithic stone artifacts in Korea typically occur in brown clay–silt (BCS) sequences. The origin and depositional environment of these sequences are important for reconstructing the paleoenvironment as well as for establishing chronologies of artifact-bearing stratigraphic units. We investigated four BCS-bearing sections in foothills and river and marine terraces in Korea by applying quantitative mineralogical, geochemical, microtextural, and K–Ar isotopic methods. In all four sections, the lower units are colluvial and fluvial deposits strongly influenced by diverse local lithology, whereas the upper units are characterized by BCS units. Mineralogical/geochemical compositions, grain sizes, and colors converge into common properties in the upper BCS units in all sections. These common properties are consistent with the eastward trends of increasing weathering degree and grain size fining throughout the loess–paleosol sections of the Chinese Loess Plateau (CLP). K–Ar detrital ages of the sections also converge upward into a narrow range similar to the age ranges of the loess and paleosols in the CLP. The top BCS unit in the Jeongok section, the thickest section, is underlain by an additionally weathered BCS unit, with strong red chroma indicating a change from warm to cold climate. We did not observe any clear evidence of climatic changes in other thinner sections, which may be due to a superposition of cold-stage accumulation and warm-stage deep weathering. The common properties of the BCSs in Korean sections and their relationship to the CLP loess and paleosols indicate widespread deposition of Asian dust and subsequent weathering in the late Quaternary, forming BCS sequences. In this respect, the BCS sequences investigated here are considered to be the additionally weathered equivalents of the CLP loess–paleosol sequences, having been exposed to the high annual precipitation of the Korean Peninsula. Given the wide distribution of BCS sequences at Paleolithic sites throughout the Peninsula, the findings of this study are important for the ongoing debate surrounding the depositional environments of the Paleolithic deposits, and provide a foundation for the establishment of the chronological framework of the Paleolithic artifact-bearing layers and lithic assemblages.

Asynchronous records of Brunhes/Matuyama reversal in marine sediments and Chinese loess: Review and discussion

Geomagnetic polarity reversals are generally considered to occur synchronously around the world, and are commonly used as time markers to correlate events between different sediment archives. They also play an indispensable role for understanding the mechanisms which generate the Earth's geomagnetic field. Nevertheless, in the case of the most recent reversal, the Brunhes–Matuyama (B/M) reversal (∼780 ka), comparison of paleomagnetic studies in Chinese loess–paleosol sequences versus marine cores reveal a marked discrepancy in timing of this event. This timing offset has led to uncertainties in correlating the Chinese loess-paleosol sequences with other global climate records. This paper briefly reviews the history of study on the B/M reversal both in marine and Chinese loess sediments, and reviews several contentious explanations of the aforementioned B/M boundary offset. Finally, the most recent progress of paleogeomagnetic field variation studies using cosmogenic 10Be in Chinese loess is introduced, with the purpose of suggesting a potential way to address this B/M boundary timing offset issue.

Molecular characterization of organic matter in Canadian Arctic paleosols for paleoecological applications

The preservation of soil organic matter (SOM) in loess–paleosol sequences from the Klondike goldfields in the Canadian Arctic has recorded several Quaternary glacial–interglacial cycles. Both non-targeted and targeted molecular organic geochemical techniques are employed to provide an additional approach to confirm and expand on existing reconstructions of late Quaternary environments in this region. Solid-state nuclear magnetic resonance (NMR) techniques performed on 31 paleosol samples formed during marine isotope stage (MIS) 2 and MIS 4 showed similar SOM characteristics. However solution-state NMR of the base-soluble extracts detected a large amount of vascular plant inputs and preservation. Biomarker analysis revealed a large predominance of constituents from higher plants such as long chain n-alkyl lipids, hydroxyl n-alkyl lipids, sterols and terpenoids. Vegetation source proxies based on the distribution of n-alkanes were inconclusive, however when combined with additional targeted extractions of hydrolysable lipids and lignin-derived phenols, it was revealed that the major vegetative sources originated from woody and non-woody angiosperms. In addition, a novel thiazole–sulfur biomolecular structure in a paleosol from the Goldbottom Creek, 14C dated to 25.3kyr before present (BP), was observed by solution-state NMR. This type of molecule has not been previously detected in base-soluble extracts of SOM. Although the origin and preservation of this structure is unknown, a mechanism based on microbial biomolecular intermediates is proposed. The spectra also contained large resonances attributed to plant cuticle functional groups providing further evidence of plant-derived material preservation. Collectively, this comprehensive dataset agrees with paleoecological hypotheses derived from physical morphology and plant macrofossils suggesting that these molecular methods may be applied as an alternative technique for Arctic paleoclimate studies as well as identification of molecular constituents not previously identified in modern soils.

Humid glacials, arid interglacials? Critical thoughts on pedogenesis and paleoclimate based on multi-proxy analyses of the loess–paleosol sequence Crvenka, Northern Serbia

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 ~140ka. 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 δD 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).

Timing and spatial distribution of loess and loess-like sediments in the mountain areas of the northeastern Tibetan Plateau

Most studies on landscape evolution on the Tibetan Plateau during the late Quaternary have mainly focused on using lacustrine records. However, mantles of sandy silt and paleosols also provide valuable archives for reconstructing Holocene paleoenvironmental change. Yet little is known about the distribution and timing of these late Quaternary aeolian sediments. To enhance understanding and knowledge of aeolian sediments in Tibet and to help reconstruct the nature of Late Glacial through mid-Holocene landscape development, a loess–paleosol sequence, the Suohuduo section, located at the eastern margin of the Tibetan Plateau at about 4000m above sea level is examined using sedimentological, geochemical and geochronological methods. A chronostratigraphy is established using nine optically stimulated luminescence and one radiocarbon ages. Sedimentation increased during the Late Glacial and the early Holocene with an upwards fining of sediments in the lower part of the section. Two mid Holocene paleosols that date to about 8.5ka to 7ka and ~5.5ka to 4ka reflect more humid climate conditions during the mid-Holocene than earlier times. The upper part of the section is mainly silt, which reflects a more open landscape with higher aridity since 4 to 3ka this time. These data support evidence for similar climate/paleoenvironmental change in adjacent regions on the Tibetan Plateau.

Paleo-pedological record of the Rocourt pedosequence at Veldwezelt–Hezerwater (Belgian Pleistocene loess belt): Part 2 — Soil formation

As the environment influences soil formation, Quaternary loess–paleosols provide an important, yet complex source on former climate and vegetation conditions. This study revises the paleopedological record of the Rocourt-complex, the pedostratigraphic marker for the Eemian and early Weichselian in the Belgian loess belt. Depth functions were established from an exceptionally well-preserved, in-situ sequence. Based on soil micromorphological features, total element contents, iron fractions and carbon content a reconstruction was made of the polygenetic formation of the Rocourt soil. Results indicate that only by combining multiple soil features, consistent information could be obtained. Furthermore, this study shows that cryogenic processes, transport of colloids, iron dynamics, redox-conditions, organic matter formation and biological activity were major soil forming processes. The hypothesis of six major stages of soil formation under varying climatic conditions was most supported by the data. During the warm to temperate oceanic climate of the Eemian, a strongly weathered argic horizon was formed. This horizon was later disrupted by reticulate ice segregation and stagnogley during the severe and prolonged cold conditions of the first cold stadial following the Eemian. Weak soil formation, during the relatively short continental St. Germain I interstadial, subsequently formed cambic soil properties and a humiferous horizon in a mixture of local and new sediments. These soils were disrupted by fragipan Formation, with its associated cryogenic structure, banded eluviation and redoxfront, during the succeeding stadial with periglacial conditions. During the St. Germain II, another A horizon formed in new, calcareous material during more stable climatic conditions, allowing organic matter build-up, eluviation of smectite and formation of pedogenetic iron. During the evolution from this warmer climate with forest or forested steppe to eventually periglacial open tundra, an accretionary humiferous soil concluded the last episode of soil formation before the onset of pleniglacial Weichselian conditions.

Modeling dust emission response to North Atlantic millennial-scale climate variations from the perspective of East European MIS 3 loess deposits

Abstract. European loess sequences of the Marine Isotope Stage 3 (~60–25 kyr BP) show periods of strong dust accumulation alternating with episodes of reduced sedimentation, favoring soil development. In the western part of the loess belt centered around 50° N, these variations appear to have been related to the North Atlantic rapid climate changes: the Dansgaard–Oeschger (DO) and Heinrich (H) events. It has been recently suggested that the North Atlantic climate signal can be detected further east, in loess deposits from Stayky (50°05.65' N, 30°53.92' E), Ukraine. Here we use climate and dust emission modeling to investigate this data interpretation. We focus on the areas north and northeast of the Carpathians, where loess deposits can be found, and the corresponding main dust sources must have been located as well. The simulations were performed with the LMDZ atmospheric general circulation model and the ORCHIDEE land surface model. They represent a reference "Greenland stadial" state and two perturbations, seen as sensitivity tests with respect to changes in the North Atlantic surface conditions between 30° and 63° N: a "Greenland interstadial" and an "H event". The main source for the loess deposits in the studied area is identified as a dust deflation band, with two very active spots located west-northwest from our reference site. Emissions only occur between February and June. Differences from one deflation spot to another, and from one climate state to another, are explained by analyzing the relevant meteorological and surface variables. Over most of the source region, the annual emission fluxes in the "interstadial" experiment are 30 to 50% lower than the "stadial" values; they would only be about 20% lower if the inhibition of dust uplift by the vegetation were not taken into account. Assuming that lower emissions result in reduced dust deposition leads us to the conclusion that the loess–paleosol stratigraphic succession in the Stayky area reflects indeed North Atlantic millennial variations. In the main deflation areas of Western Europe, the vegetation effect alone determined most of the (~50% on average) stadial–interstadial flux differences. Even if its impact in Eastern Europe is less pronounced, this effect remains a key factor in modulating aeolian emissions at the millennial timescale. Conditions favorable to initiating particularly strong dust storms within a few hundred kilometers upwind from our reference site, simulated in the month of April of the H event experiment, support the correlation of H events with peaks in grain size index in some very detailed loess profiles, indicating increased coarse sedimentation.

Iron mineralogical proxies and Quaternary climate change in SE-European loess–paleosol sequences

The loess–paleosol sequences Batajnica/Stari Slankamen (Serbia) and Mircea Voda (Romania) represent key archives for the climate and landscape development of the middle and lower Danube Basin during the last 700,000years. For deciphering the Quaternary climate evolution in these regions, the Batajnica/Stari Slankamen and Mircea Voda sites are for the first time studied by a multi-proxy approach based on iron mineralogical parameters. Changes in the iron mineralogical composition are identified and characterized by rock magnetic investigations, diffuse reflectance spectroscopy (DRS) and Munsell color based proxies. The results show that environmental conditions during mid- and early Middle Pleistocene interglacials were more favorable for hematite formation, suggesting a more oxidizing pedoclimate as in the more recent interglacials. This is also reflected in a gradual increase of the anhysteretic remanent magnetization vs. saturation isothermal remanent magnetization (ARM/SIRM) ratio. In the studied profiles changes in this ratio can be linked to a preferential hematitization of coarse-grained ferrimagnetica and relates to warmer climate conditions and a more extended estival dry period. At the same time, rock magnetic parameters indicate a preferential destruction of fine-grained magnetic particles in older paleosols resulting from seasonal excess moisture.A progressive cooling and decrease of rainfall during the Middle and Late Pleistocene is evidenced not only for interglacial pedocomplexes but also for glacial loess layers. This finding is in line with previously published proxy records of silicate weathering and clay formation at these sites and similar trends reported from other sites in the European steppe belt. Relating iron mineralogical proxies to paleopedological characteristics and proxies of silicate weathering, additionally a change in the seasonal pattern of the interglacial temperature and precipitation regime from a Mediterranean type to a steppe type climate is revealed, highlighting the potential of such a multi-proxy approach.Possible triggers for this paleoenvironmental evolution are discussed, as well, finally highlighting a “Quaternary uplift hypothesis”, which best could explain the inferred trend of cooling, aridification and increasing continentality. Accordingly, changes in atmospheric circulation and rain shadow effects induced by small-scale uplift of European mountain belts (Alps, Carpathians, Dinaric Alps) would provide a driving mechanism for the westward extension of the Eurasian steppe belt into Central and SE-Europe during the Quaternary.

The progressive evolution of a continental climate in southeast-central European lowlands during the Middle Pleistocene recorded in loess paleosol sequences

Research Article| July 01, 2013 The progressive evolution of a continental climate in southeast-central European lowlands during the Middle Pleistocene recorded in loess paleosol sequences Björn Buggle; Björn Buggle * 1ETH Zürich, Department of Earth Sciences, Biogeoscience Group, Sonneggstrasse 5, 8092 Zurich, Switzerland2Chair of Geomorphology, University of Bayreuth, 95440 Bayreuth, Germany *E-mail: Bjoern.Buggle@uni-bayreuth.de. Search for other works by this author on: GSW Google Scholar Ulrich Hambach; Ulrich Hambach 2Chair of Geomorphology, University of Bayreuth, 95440 Bayreuth, Germany Search for other works by this author on: GSW Google Scholar Martin Kehl; Martin Kehl 3Institute of Geography, University of Cologne, 50932 Cologne, Germany Search for other works by this author on: GSW Google Scholar Slobodan B. Marković; Slobodan B. Marković 4LAPER—Laboratory for Paleoecological Reconstruction, Faculty of Sciences, Trg Dositeja Obradovića 3, 21000 Novi Sad, Serbia Search for other works by this author on: GSW Google Scholar Ludwig Zöller; Ludwig Zöller 2Chair of Geomorphology, University of Bayreuth, 95440 Bayreuth, Germany Search for other works by this author on: GSW Google Scholar Bruno Glaser Bruno Glaser 5Soil Biogeochemistry, Martin-Luther-University Halle-Wittenberg, von-Seckendorff-Platz 3, 06120 Halle, Germany Search for other works by this author on: GSW Google Scholar Geology (2013) 41 (7): 771–774. https://doi.org/10.1130/G34198.1 Article history received: 06 Nov 2012 rev-recd: 16 Feb 2013 accepted: 19 Feb 2013 first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Björn Buggle, Ulrich Hambach, Martin Kehl, Slobodan B. Marković, Ludwig Zöller, Bruno Glaser; The progressive evolution of a continental climate in southeast-central European lowlands during the Middle Pleistocene recorded in loess paleosol sequences. Geology 2013;; 41 (7): 771–774. doi: https://doi.org/10.1130/G34198.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Little is known about the long-term Quaternary climate evolution of central and southeast Europe, because suitable terrestrial paleoenvironmental records are scarce. We present a multiproxy record of loess paleosol sequences in the Middle and Lower Danube Basins over the past 700 k.y. In these lowlands, the continentality of interglacial climate progressively increased during the Middle Pleistocene. Corresponding trends are seen in other climate proxies in the same region and in the lowlands of the northern Black Sea, but not, or less clearly, in climate archives from outside these lowlands. We conclude that a small-scale increase in paleoelevation of central European mountain ranges (the Alps, Carpathians, and Dinarides) during the Middle Pleistocene might be the cause of the progressive increase in climate continentality of southeast European lowlands. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Archaeological sites of the Süttő Travertine Complex (Hungary) with stratigraphical and paleoecological implications from their faunas

The Süttő Travertine Complex in northern Hungary is known in the geological literature for more than a century as a series of paleontological sites. This site is one of the largest travertine occurrences of the Gerecse Hills. Loose Upper Pleistocene eolian sediments (mainly Riss-Würmian loess and Holocene topsoil) cover the eroded surface of the travertine. Beside vertebrate assemblages, two archaeological sites were described from this area. One (Süttő-Diósárok) was a Paleolithic fire pit situated in the road cut between Süttő and the quarries, while the other one was discovered in a fissure of the northern wall of Diósvölgy Quarry. The latter is part of the Süttő 1 vertebrate site.Vértes (1965) referred the artifacts from Süttő-Diósárok to the Moustérian (Tata Culture). This site is referred here to MIS 5c, based on the vertebrate and snail faunas representing warm and dry climate, and steppe-like vegetation, as well as the tool-bearing dark brown chernozem-like paleosol layer of the loess–paleosol sequence, with a luminescence age of 93.7 ± 21.1 ka.Artificially fractured bones were excavated from the small cavity of Süttő 1. Some of those remains display toolmarks. Unfortunately, these bones are currently missing from the collection. The latter artifacts most likely belong to a level which pre-dates the Tata Culture. Paleoecological inferences based on the mammalian and mollusc faunas indicated warm, humid climate and forest vegetation, therefore suggesting a stratigraphic correlation of Süttő 1 with the Eemian interglacial (MIS 5e).

The significant role of inorganic matters in preservation and stability of soil organic carbon in the Baoji and Luochuan loess/paleosol profiles, Central China

Abstract The preservation and stability mechanisms of soil organic carbon (SOC) are the important factors to evaluate the capacity of soil carbon pool and the potential of sustainable utilization. To understand the preservation time and mechanisms of SOC under burial conditions, in the present study, the distributions of total organic carbon (TOC) and stable organic carbon (StOC), and their correlations with the contents of clays and clay minerals and different forms of iron oxides were investigated in the Baoji and Luochuan loess–paleosol profiles. Four facts were observed as the followings. (1) The labile SOC almost was decomposed and the mostly stable SOC was preserved in the loess and paleosol after 375 kyr since their formation. StOC could be preserved at least 762 kyr in both loess and paleosol under burial condition. (2) The TOC was positively correlated with clay contents, with correlation coefficients of 0.72 (Baoji) and 0.63 (Luochuan). (3) The TOC, StOC, mineral-protected organic carbon (MOC), and recalcitrant organic carbon (ROC) were positively correlated with kaolinite, with correlation coefficients of 0.93, 0.72, 0.52, 0.81 (Baoji) and 0.78, 0.58, 0.50, 0.49 (Luochuan), respectively, both with neither illite nor vermiculite. (4) The TOC was highly correlated with complex iron (Fe p ) with correlation coefficients of 0.90 (Baoji) and 0.82 (Luochuan), so with amorphous oxides of iron (Fe o ) as well. Among them, Fe o mainly affected by sorption and Fe p by complexation on SOC preservation, whereas kaolinite had both chemical and physical effects. The values of coefficients further highlight that the contributions of inorganic matters to the fixation of organic carbon were ranked to an order of kaolinite > Fe p > Fe o .

Characterizing the superparamagnetic grain distribution of Chinese red-clay sequences by thermal fluctuation tomography

Although magnetic susceptibility (χ) is a widely accepted East Asian summer monsoon (EASM) intensity proxy for Quaternary loess, debates exist about whether χ can be used to indicate EASM intensity for the red-clay sequence. In order to use χ of the red-clay sediments to indicate EASM intensity, χ should have the same sort of enhancement mechanisms as in Quaternary loess. However, this similarity has not been rigorously demonstrated. Previous estimates of magnetic grain size distribution of Chinese loess and red-clay are based on out-of-phase magnetic susceptibility inversion technique. This technique assumes that the coercivity of pedogenic magnetic grains is independent of temperature, and at any temperature, only a single grain size contributes to frequency-dependent or quadrature susceptibility, rather than a distribution of sizes. Thermal fluctuation tomography is a recently developed more rigorous inversion technique for characterizing the grain-size distribution of superparamagnetic (SP) and single domain grains with fewer assumptions. Here we apply this technique to the Chinese red-clay sequence of the Chaona section, central Chinese Loess Plateau, and the overlying loess–paleosol sequence to better characterize the size distribution of SP grains of the Chinese red-clay sequence. We found that SP grain-size distributions of both paleosol and red-clay from the Chaona section are similar. The results reinforce a previous conclusion supporting the idea that magnetic susceptibility (χ) can be used to indicate the intensity of the EASM in the red-clay sequence.

Characterizing and quantifying iron oxides in Chinese loess/paleosols: Implications for pedogenesis

To accurately decode the paleoclimatic and paleoenvironmental significance of magnetic properties in Chinese loess/paleosols, neoformation of magnetic iron oxides via pedogenesis as well as the relationship between ferrimagnetic (maghemite and magnetite) and antiferromagnetic minerals (hematite and goethite) of both detrital and pedogenic origins should be well determined. To resolve this problem, magnetic iron oxides from a contiguous loess–paleosol sequence (lower part of the loess unit L1, paleosol unit S1, and the upper part of L2) at Luochuan, Center of the Chinese Loess Plateau, were well characterized and quantified by using an integrated approach including chemical dissolution, diffuse reflectance spectroscopy and rock magnetism methods. Results showed that these magnetic minerals have distinct coercivity and dissolution behavior, which is highly grain size-dependent. More specifically, the paleosol is enriched with nano-sized pedogenic hematites with a medium coercivity of ~130mT, which are also preferentially dissolved in a weak reductive environment. In contrast, the coarse-grained micro-sized detrital hematites with a medium coercivity of ~1T are dominant in loess. In addition, these coarse-grained detrital hematites are more stoichiometric than their pedogenic counterparts as evidenced by the higher band position on the diffuse reflectance spectrum. Goethite can be well distinguished from hematite by its higher coercivity (4–7T) at low temperature (10K). The consistent dissolution behavior of goethite for both loess and paleosol samples in citrate–bicarbonate–dithionite solution indicates that goethite could be less relevant to the pedogenic processes. The reductive dissolution of pedogenic maghemite lags the dissolution of pedogenic hematite and fine-grained goethite, which suggests that average grain size of pedogenic maghemite is relatively larger than those of pedogenic hematite and fine-grained goethite. Detrital magnetite is hard to dissolve and ~50% of its initial remanence survived after dissolution. On the basis of these contrasting behaviors, pedogenic hematite, fine grained goethite and maghemite content was further quantified. Our results suggest that single domain pedogenic hematite was produced after initial formation of pedogenic maghemite. This provides direct evidence for the recently proposed pathway in which ferrihydrite is transformed into a transient maghemite-like phase before its final transformation into hematite.

Geochemical characteristics and environmental significance of Talede loess–paleosol sequences of Ili Basin in Central Asia

The loess–paleosol deposit in Central Asia is a sensitive indicator of the evolution of the quaternary paleoclimate in the Westerlies, providing insight into the quaternary climate history and its relationship with global climatic changes. Based on the geochemical analysis of elemental composition of densely sampled strata from Talede loess–paleosol sequence in the Ili Basin, the results showed that SiO2 had the highest major elements content, followed by Al2O3. The order of compositional abundance of major elements was generally as follows: SiO2 > Al2O3 > CaO > Fe2O3 > MgO > Na2O > K2O. Trace elements (i.e. Rb, Sr, Sc, Ni, Cu, Ga, Mo, Y, Pb, Th) in the paleosol layers (i.e. S 0, S m, S 1) and the loess layer of L 1 were enriched relative to underlain loess (L 2) horizons, except for the contents of Zr, Cs, Nd, and La in paleosol layers. All of geochemical proxies, such as enrichment factor, Rb/Sr ratio, eluvial coefficient (K i ) and chemical weathering index, display no obvious differentiation in the Talede loess–paleosol deposit. The results indicate that the weak chemical weathering, greater evaporation and low effective moisture in Ili Basin, are to a degree weaker than those in the China Loess Plateau and the climate was warm–dry during the interglacial period. In addition, the loess of Ili area is rich in schistose minerals and implies that the loess may come from the deserts of Central Asia and it may be closely related to the widespread aridification of Central Asia.

Paleo-pedological record of the Rocourt Pedosequence at Veldwezelt–Hezerwater (Belgian Pleistocene loess belt): Part 1 — Evolution of the parent material

As the environment influences soil formation, loess–paleosols are important archives of former climatic conditions. However, this record is highly complex and all features need to be evaluated in order to obtain consistent information on soil formation. This study revises the pedological record of the Rocourt-paleosol complex, an important pedo-stratigraphic marker for the Eemian and Early Weichselian, at an exceptionally well-preserved in-situ sequence (Veldwezelt–Hezerwater, Belgian loess belt). Contrasting hypotheses exist considering the evolution of the parent material after the deposition of the Saalian loess and on the importance of aggrading aeolian deposition. In this study, soil morphological features and depth functions of X-ray diffraction, grain-size distribution, CEC, base saturation, total Fe, Al, K, Na and Ca content, pH and electrical conductivity were established to reconstruct deposition dynamics, weathering and carbonate content of the parent material. Texture analysis confirms the petrostratigraphic homogeneity of the parent material and suggests that it developed under a regime of fluctuating rates of primary dust deposition intermixed with periods of (fluvial) reworking of the dust. Strong weathering was identified in the lower stratigraphic unit, supporting the general consensus that it formed during the Eemian in Saalian loess. Less information is present to confirm the origin of the upper, less developed illuvial units, which may have formed by welding or by pedogenesis in locally redistributed or aeolian material. The overlying A-horizons are clearly less weathered, and evidence for early recalcification indicates that deposition of unweathered, calcareous sediments gained importance during the formation of these horizons.

Pleistocene vertebrate faunas of the Süttő Travertine Complex (Hungary)

Numerous fossil remains (vertebrates, molluscs and plants) were found in more than twenty sites of the Süttő Travertine Complex during the last 150 years. The majority of these remains were recovered from fissures of the travertine, but also from the travertine and an overlying loess–paleosol sequence. The aims of this study were to review the fossil content, to determine the stratigraphical positions of the various vertebrate faunas of Süttő and provide paleoecological interpretation of the periods on the basis of their faunas and floras. In addition, this paper describes new faunas and floras from the sites Süttő 16–20 and provides 14C dates for Süttő 16.On the basis of the new uranium series isotope and optical dating (OSL), the age of the travertine complex is Middle Pleistocene (235 ± 21–314 ± 45 ka, MIS 7–9), while the age of the loess–paleosol sequence in superposition of the travertine is Middle–Late Pleistocene (MIS 2–MIS 6). In contrast, the fossils of the travertine indicated an older, Pliocene–Early Pleistocene age. A fissure (Süttő 17) and a red clay layer (Süttő 19) contained mammal faunas of Early–Middle Pleistocene age. These results indicated the existence of older travertine in certain quarries (Hegyháti quarry, Cukor quarry).Sedimentological and OSL data of well-dated layers of the loess–paleosol sequence (Süttő/LPS) at Süttő allowed a correlation with the layers of Süttő 6. The paleosol layer in the upper part of the sequence of Süttő 6, was correlated with a pedocomplex of the overlying loess–paleosol sequence, which was dated to MIS 5c (upper, dark soil) and MIS 5e (lower, reddish brown soil). The paleoecological analysis of the mammal and mollusc faunas supported the former interpretation of Novothny et al. (2011) inferring warm, dry climate during the sedimentation of the upper layers, and more humid climate for the lower layers). However, the fauna of the lower soil layer indicated cold climate, so an age of MIS 5d is suggested.Dating of the fissure faunas is based on similarity studies. For some faunas, this method cannot be used, because of the low number of species. On the basis of the species compositions and former interpretations, these faunas originated mainly from sediments that were deposited under cold climatic conditions. Other fissure faunas were dated by AMS 14C (Süttő 16), or by correlation with soil layers of Süttő 6. According to these results, most of the fissure faunas can be correlated with different phases of MIS 5. However, there are a younger (MIS 2) and an older (Early–Middle Pleistocene) fissure fauna also.

Late Pleistocene landscape dynamics in Saxony, Germany: Paleoenvironmental reconstruction using loess-paleosol sequences

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.

TT-OSL dating of Longyadong Middle Paleolithic site and paleoenvironmental implications for hominin occupation in Luonan Basin (central China)

Dating middle Pleistocene hominin occupations alongside the reconstruction of paleoenvironments in China between 700 and 100ka has always been a challenging task. In this paper, we report thermally transferred optically stimulated luminescence (TT-OSL) dating results for a Middle Paleolithic site in the Luonan Basin, central China, which we have named Longyadong Cave. The results suggest that the age of cave infilling and the deposition of sediments outside the cave range between 389±18 and 274±14ka. These deposits are stratigraphically and geochronologically correlated with the L4 loess and S3 paleosol units of the typical loess–paleosol sequence of the Chinese Loess Plateau, and with Marine Isotope Stages (MIS) 10 to 9, respectively. On the basis of these new ages and the available paleoenvironmental data, it is suggested that the Longyadong hominins might have occupied the site both in glacial and interglacial periods, demonstrating that they coped well with environmental change in this mountainous region in warm/wet and cold/dry climates. The study further implies that the hominins abandoned the Longyadong Cave between 274±14 and 205±19ka, when it was sealed by alluvial and slope deposits.