Search

We present stratigraphic, magnetic, diffuse reflectance spectrophotometric analyses, and chronologic data for the Chenarli loess–paleosol sequence in northeastern Iran. Eight loess units (LU) are identified, described, and constrained in time based on relative stratigraphy and luminescence dating from >130 ± 9.1 ka to ~9.8 ± 0.7 ka. Our data indicate that pedogenic magnetite/maghemite formation gives rise to magnetic enhancement in modern soil and paleosols. The top of LU 7 is demarcated by the well-developed last interglacial soil in which magnetic depletion occurred. We infer that magnetic depletion in this paleosol was produced by reducing conditions in a seasonally waterlogged soil during a warm and wet phase within Marine Isotope Stage (MIS) 5e. Units LU 6 to 1 record several episodes of dust accumulation and soil formation during the last glacial and Holocene. Increased dust accumulation rates occurred during middle-late MIS 3 and lasted into the late MIS 2, with a peak during the last glacial maximum (LU 2). These findings could be applicable to understanding magnetic enhancement/dissolution mechanism in the loess–paleosol sequences in study area. We infer paleoenvironmental changes in northeastern Iran relative to northern Iran, Eurasia, and China.

The “tablelands” in Taiwan are sedimentary terraces occurring in the foreland basin west of the Neogene mountain ranges. The Miaoli Tableland consists of elevated Late Quaternary sedimentary successions, representing a change from tidal to coastal and fluvial to eolian depositional environments. The present-day morphology is a result of combined processes, including differential tectonic uplift, ongoing fluvial aggradation, and incision. Selected deposits in 10 outcrops were sampled and studied by optical dating. The deposition of fluvial sediments started after the last interglacial (

Die Altersstellung des Stauchmoränenkomplexes Wallsbüll-Böxlund in Schleswig-Holstein ist trotz jahrzehntelanger Untersuchungen noch ungeklärt. Die in einem Aufschluss in Osterbylund (OBL) aufgeschlossenen Sedimente und Torfe sowie Böden wurden zur Klärung dieser Frage und auch zur Korrelation der Böden OBL 1 bis OBL 4 mit den bekannten Interglazialen und Interstadialen mittels optisch stimulierter Lumineszenz und Uran-Thorium sowie Pollenanalysen datiert. Detaillierte sedimentologische Aufnahmen ergänzten die chronologischen Arbeiten. Die Pollenanalysen ordnen den in Depressionen vorkommenden Torf dem Eem zu; der Torf ist mit OBL 1 gleichzusetzen. Die aufliegenden Sande und die übrigen eingeschalteten Böden können alle in das Frühweichsel gestellt werden. Während für OBL 2 die Stellung in das Brörup-Interstadial aufgrund der Daten belegbar ist, gestalten sich die Zuordnungen für OBL 3 und OBL 4 etwas schwieriger, da schlechte Bleichung der umineszenzsignale der Sande insbesondere oberhalb von OBL 4 Unsicherheiten mit sich bringen.Unter Berücksichtigung der Gesamtheit der Daten ist eine Korrelation von OBL 3 mit dem Odderade-Interstadial und von OBL 4 mit dem Keller-Interstadial am wahrscheinlichsten. Aus diesen Daten ergibt sich zudem eine saalezeitliche Entstehung des Stauchmoränenwalls; ein, wie in anderen Studien angenommen, weichselzeitlicher Eisrand noch weiter westlich als der hier untersuchte Standort kann somit ausgeschlossen werden. The age of the push moraine complex Wallsbüll-Böxlund, Schleswig-Holstein, is unclear despite investigations in this area for decades. To address the timing of formation of both the push moraine complex and the peat and soils found in its depressions, an outcrop in Osterbylund (OBL) was investigated. Optically stimulated luminescence and dating, as well as pollen analyses, were undertaken with the aim to correlate the soils OBL 1 to OBL 4 to interglacials and interstadials. The chronological studies were accompanied by detailed sedimentological investigations. The results of the pollen analyses put the peat unambiguously to the Eemian; the peat is equivalent to OBL 1. The overlying sands and the other intercalated soils are to be placed into the early Weichselian. While for OBL 2 the assignment to the Brörup interstadial is clear, it is more difficult to clearly correlate OBL 3 and OBL 4 to an interstadial due to poor luminescence signal resetting of the sands, especially above OBL 4. Considering all data available, it is most likely that OBL 3 formed during the Odderade interstadial and OBL 4 during the Keller interstadial. From the Eemian to early Weichselian ages of the peat and soils it is evident that the push moraine complex is of Saalian age; a Weichselian ice margin further in the west, as assumed in other studies, can therefore be excluded.

Here we present loess deposits since the late glacial dated by OSL technique in the southeast of the Caspian Sea, bordering continents of Asia and Europe. Chronology of Holocene loess deposits are rarely reported in Eastern Europe and Western Asia, especially for their spacious mid-latitude adjacent region, between Balkans to the west and Pamirs to the east. In this study, an OSL-based chronology was developed for loess deposits in northern Iranian Plateau, based on the YBD loess profile which locates close to center of hilly Iranian Loess Plateau in the southeast of the Caspian Sea and on the northern slope of the Alborz Mountains. The OSL characteristics and their reliability were investigated on coarse-grained quartz (63–90 μm) of the profile, a preheat plateau test and dose recovery test of which reveal that the lower preheat is suitable for loess equivalent dose determination in the area. In addition, the SAR-OSL is an appropriate methodology for dating loess deposited since the late glacial in situ. With preservation of a complete record of loess accumulation since the late glacial, YBD section contains a potentially valuable paleoclimatic record for Caspian region and hence the vast transitional region between Asia and Europe.

Optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL) methods using quartz and potassium-rich feldspar, respectively, have been successfully applied to deposits from a variety of different sedimentary environments to determine the time elapsed since the last exposure to sunlight. Coastal sediments including aeolian and shallow marine deposits have been proved to be excellent material for dating, because they fullfill the basic luminescence dating assumptions such as sufficient bleaching/zeroing prior to deposition. Furthermore, in combination with radiocarbon dating robust and reliable chronological frameworks have been provided.In this paper, we present two luminescence dating case studies. The first one is about a sediment core including Holocene sediments from the German North Sea Coast, previously studied by Zhang et al. (2014) and extended by a sediment core from an inland barrier spit at Eiderstedt peninsula. The lithostratigraphic, sedimentological and chronological investigations yielded the following interpretation: The uppermost 1-2 meter of the sediments are of terrestrial origin and deposited after the construction of dykes along the coast during the 11th century. These results are in agreement with sedimentological and chronological results from two further localities in the vicinity of the key location. More than 20 m of shallow marine sediments are exposed including a marker horizon rich in shells and shell fragments giving evidence for the rapid Holocene sea-level rise and the arrival of the “sea” at around 8,300 Years BP at the locality under study. Wadden sediments, mud and sand flats sediments and beach wall or barriere spit sediments are typical for the Holocene sequence. A hiatus is found for the time period between 13,000 and 8,300 years BP. Last glacial deposits up to a depth of at least 70 m consist mainly of (reworked) aeolian and fluvial sediments.The sediment successions along the coast of Sardinia provide important information about the Late Pleistocene – Holocene sea-level changes and sea-level elevations. However, the chronological results of different dating methods, such as OSL, IRSL, electron-spin resonance, radiocarbon, uranium/thorium and amino acid racemisation are not sound and have been a matter of debate for many years. We will discuss the reliability of the different dating methods and present new radiocarbon and luminescence dates as the second case study. Zhang, J., Grube, A., Tsukamoto, S., Frechen, M. (2014): OSL and 14C chronologies of a Holocene sedimentary record (Garding-2 core) from the German North Sea coast.- Boreas, 43: 856-868.

The North Jiangsu Basin (NJB), located in the western part of the North Jiangsu-South Yellow Sea Basin, is a critical region providing invaluable archives about the evolution processes of the land-ocean interchange and climatic environments in a coastal zone. Chronology is of crucial importance to reconstruct the timing of sea-level eustacy, and shoreline changes, as well as the evolution of the regional environment by means of numerical dating to determine the age of sedimentary strata in the sea–land interaction zone of the NJB. However, sediment dating in the NJB remains controversial due to limitations in the quantity and quality of chronological data. Therefore, the sediments in the Jianhu Gangxi (GX) profile of the NJB were analyzed in this study by applying both fine-grained quartz optically stimulated luminescence (OSL) dating and 14C dating. The results were used to discuss the processes of regional environment evolution. The OSL dating of fine-grained quartz components in sediments was found to be a reliable method to determine deposition ages of sediments in the land-sea interaction zone in the NJB. The combination of OSL and accelerator mass spectrometry 14C dating techniques allowed a reliable and high-resolution chronological framework for the GX profile. Since the last glaciation, the sedimentary environment in the eastern portion of the NJB changed significantly. In particular: (1) between 13 and 7.25 ka B.P, the area of interest was dominated by lacustrine deposition within a stable sedimentary environment with low deposition rates; (2) from 7.25 to 6.45 ka B.P, marine transgression events occurred, and the deposition rate increased rapidly in an area of land-sea interaction; (3) after 6.45 ka B.P, a regression event occurred, and the study area transformed into a lowland lake environment.

Stable carbon and oxygen isotope compositions in soil carbonates and in soil organic matter provide insights into (paleo) climatic conditions, especially in arid and semiarid regions where carbonate is abundant in soils. We here investigate δ13C and δ18O isotope composition of bulk carbonate, pedogenic carbonate nodules and organic carbon from modern soils developed along a precipitation gradient (Entisol, Inceptisol, Mollisol and Alfisol) and paleosols formed within loess units in northern Iran. δ13C values of organic carbon in the modern soils ranged from −19.5‰ in the arid and semiarid regions to −24‰ in the more humid regions with forest vegetation. δ13C values of bulk carbonate in the modern soils ranged from −12.1‰ at the wettest sites to −0.8‰ at the drier sites and thus, a 550 mm increase in precipitation leads to a ~11‰ decrease in δ13C values of bulk carbonate. In the modern soils, δ13C values of pedogenic carbonate nodules in the semiarid areas show higher values by ~3–4‰ more than the regions with forest vegetation. Unlike δ13C values of pedogenic carbonate nodules the δ18O values of pedogenic carbonate nodules of modern soils in this study did not display pronounced changes across the sections. The change in δ13C of carbonates and organic carbon is consistent with the present above-ground vegetation, consisting of a mosaic of habitats with differences in the proportion of C3 and C4 vegetation tending to larger C4 contribution with increasing aridity. The δ13C values of carbonates coupled with climate data of the region confirm seasonal bias in the formation of carbonate nodules in the modern soils seen in studies elsewhere. The δ13C values of pedogenic carbonate nodules in the paleosols range from −10‰ in humid areas to −7.2‰ in semiarid areas. The trends in δ13C composition in modern soils are also visible in the δ13C composition in the paleosols, suggesting that in the foothills of the Alborz and Iranian loess plateau, a precipitation gradient existed also in the last interglacial.

In the Golestan province in northern Iran extensive loess deposits, and widespread loess-derived soils crop out. While a strong precipitation gradient (200–700 mm per year) from North to South is characteristic, temperature differences are negligible (17–18 °C per year). Recently, many studies on loess-derived palaeosols and modern soils from this region were published; However, in these publications only limited information on the magnetic properties of loess and loess-derived soils is given, nor the potential of these properties to be applied as proxies for palaeoclimate reconstruction. In order to study soil magnetic properties along the precipitation gradient in the Golestan province, six pedons of modern soils were selected. The physicochemical properties, the clay mineralogy and magnetic parameters of soil samples were analysed. Susceptibility measurements (20.2–130.77 × 10−8 m3kg−1), ARM susceptibility values (0.00489–0.068 m3kg-1), IRM values (0.0027–0.0105 Am2kg−1), and hysteresis measurements provide significant evidences for an increase of the content of fine grained ferromagnetic minerals with increasing mean annual precipitation. Simultaneously, the amount of SP sized particles increase. Magnetite, maghemite, and hematite are the major magnetic minerals in the studied samples, whereby magnetite seems to be dominant in the soils of the loess plateau of northern Iran. By presenting data from this region of the northern Iran for the first time, another example is provided for the application of magnetic properties as proxies for the reconstruction of the paleoclimate. The results are compared to data of the Chinese loess plateau, the Russian steppe and loessic soils from the midwestern United State with similar relations of pedogenic susceptibility and MAP.

International audience; Coastal wetlands are seen in the central part of the SW coast of Kerala, India at Muriyad, Thrissur (15 km orthogonal to the present day coast towards inland) and forms a part of Vembanad kol. These wetlands are sheltered by well-developed beach ridges in the west and lateritic uplands towards east between the latitudes and longitudes of 10°20‘-10°30‘N and 76°10‘-76°20‘E respectively. The present study aims to find the evidences of early Holocene transgression in the area and constrain its chronology using optically stimulated luminescence (OSL) as well as radiocarbon dating. The general stratigraphy of the wetland section shows estuarine sandy clay at the bottom, followed by one meter thick peat unit, overlain by lacustrine clay and colluvial sediments. The fluvial sequences were devoid of peat deposits and comprised of clay and sand sequences having large fossil tree logs. OSL age of a sand layer (7.0 ± 1.0 ka) below the peat unit as well as the radiocarbon ages of peat (between 7920- 7740 and 7410- 7180 Cal years BP) itself indicates that the unit was formed between 8-7 ka ago. The peat accretion shows an average rate of 1.74 mm/a-1. The pollen analysis of the peat unit demonstrates that peat was formed from Rhizophoraceae mangrove plants, implying close proximity of the study area to the shore line. Dominance of wet evergreen forest taxa in the non-mangrove pollen of the peat indicate wet climatic conditions in the area. The occurrences of fossil wood stumps in upright position and large tree trunks buried in the fluvial succession shows that the trees were buried in-situ in the growth position/ during the transportation by flood waters in the fluvial sequence. The fluvial unit in the wetland stratigraphy shows evidences of enhanced SW monsoon in the area, causing large scale floods, submergence of forests and destruction of large trees during 5710-5610 and 6880-6750 Cal years BP.

The resilience of Neanderthals towards changing climatic and environmental conditions, and especially towards severely cold climates in northern regions of central Europe, is still under debate. One way to address this is to investigate multi-layered occupation in different climatic intervals, using independently-compiled paleoenvironmental and chronological data. Unfortunately, most open-air sites on the northern European Plain lack a robust chronostratigraphy beyond the radiocarbon dating range, thereby often hampering direct links between human occupation and climate. Here we present the results of integrative research at the Middle Paleolithic open-air site of Lichtenberg, Northern Germany, comprising archaeology, luminescence dating, sedimentology, micromorphology, as well as pollen and phytolith analyses. Our findings clearly show Neanderthal presence in temperate, forested environments during the Mid-Eemian Interglacial, MIS 5e and the latest Brörup Interstadial, MIS 5c/GI 22 (Lichtenberg II). For the previously known occupation Lichtenberg I, we revise the chronology from the former early MIS 3 (57 ± 6 ka) to early MIS 4/GS 19 (71.3 ± 7.3 ka), with dominant cold steppe/tundra vegetation. The early MIS 4 occupation suggests that Neanderthals could adjust well to severely cold environments and implies recurring population in the region between MIS 5 and MIS 3. The artefact assemblages differ between the temperate and cold environment occupations regarding size, blank production, typology and tool use. We argue that this distinctness can partially be explained by different site functions and occupation duration, as well as the availability of large and high-quality flint raw material. Raw material availability is in turn governed by changing vegetation cover that hindered or fostered sediment redeposition as a provider of flint from the primary source of the glacial sediments nearby.

Alluvial fans record climate-driven erosion and sediment-transport processes and allow reconstructing past environmental conditions. Here we investigate the sedimentation history of two alluvial fans located in formerly glaciated valleys of the Cordillera Oriental, Peru.10Be exposure ages from the fan surfaces and radiocarbon ages from the fan interiors constrain the final stages of fan formation. The10Be and14C ages cluster mainly between 13.3–9.3 ka and 11,500–9700 cal yr BP, respectively. Our age data set indicates that—after deglaciation—large amounts of fan sediment were deposited until ∼10 ka, when sedimentation rates declined rather abruptly. This pattern is supported by10Be erosion rates for the fan catchments, because under the assumption of constant erosion the time needed to erode the material stored in the fans significantly exceeds their age. Correlating our ages with regional climate records indicates that precipitation exerts the primary control on fan sedimentation. Two periods with elevated lake levels and increased precipitation between 18 and 14.5 ka and from 13 to 11.5 ka resulted in rapid deposition of large fan lobes. Subsequently, lower precipitation rates decreased erosion in the catchments and sediment delivery to the fans, which have remained largely inactive since ∼9.5 ka.

The reliability of the fading correction methods for feldspar infrared stimulated luminescence (IRSL) dating in the non-linear part of the dose response curve proposed by Wallinga et al. (2007) (modified after Lamothe et al., 2003) and Kars et al. (2008) was evaluated using samples from the Chinese loess-palaeosol sequence in Luochuan with the reference ages. Two protocols, the post-infrared (IR) IRSL at 225 °C (pIRIR225) and the pulsed IR at 50 °C, were applied in this study. The natural dose response curve (DRC) for the IR50 (pre-pIRIR225), pIRIR225 and pulsed IR50 was first constructed. The simulated-natural DRC and the fading corrected ages were then determined. The characteristic saturation dose (D0) of the simulated-natural DRC was found to be larger than that of the natural DRC for the IR50 (pre-pIRIR225) and pIRIR225 signals, whilst the two D0 values agreed with each other for the pulsed IR50. The saturation ratio (n/N) of the simulated-natural DRC agreed with the natural one within 10% uncertainty for all three signals. The fading corrected ages using these two methods agreed with the reference ages, confirming the reliability of the two fading correction methods. However, our numerical simulation on the fading correction showed that the method of Wallinga et al. (2007) significantly overcorrect ages when the fading rates are larger than ca. 4–5%/decade.

The loess-palaeosol record on the island of Susak in Croatia is a unique archive of Late Glacial climate changes in the Adriatic region, possibly even in the wider area. On Susak up to 90 m of thick Quaternary sediments were deposited, and are accessible for detailed palaeoclimate reconstructions. In this paper, the results of a high-resolution grain-size and rock magnetic investigation on the Last Glacial (Upper Pleniglacial) Sand Pit section from Susak are presented. In spite of its significant thickness, the Sand Pit section does not represent a continuous record; it is a result of a very dynamic environment. There, the deposition of dust and formation of loess has been interrupted by pedogenesis, periods of increased sand accumulation, erosion due to slope wash and water activity, redeposition and wildfires, and all in the time period of about 10.000 years of the Upper Pleniglacial, as seen from the IRSL dating results. The grain-size data clearly show a shift towards coarser grain sizes which differs from typical loess regions. Such predominance of the coarser-grained over the fine-grained fraction, very likely resulted from the predominance of deposition over pedogenesis, increased wind activity and proximal source of material. The rock magnetic signal preserved in the sediment also differs compared to loess-palaeosol records from other regions. The susceptibility values are several times higher than in the records from the Pannonian basin and from typical Eurasian loess. Both the increased susceptibility values and the grain-size are very likely the result of a significant proximal material input from the Po River plain.

A polygenetic soil formed on Late Glacial Loess on the Island of Susak was investigated by means of high-resolution depth approach to give pedosedimentary and palaeoenvironmental reconstructions of the Late Glacial/Holocene pedosequence. The complete polygenetic profile (A-2C1-2C2-3Btb-4Ck), defined as Eutric Leptic Regosol (Geoabruptic, Siltic, Ruptic) over Argic horizon over loess deposit, is a result of the interaction of the sediments (loess) with environmental conditions from the Late Glacial throughout the Holocene. Both normal pedogenesis and erosion/sedimentation-driven pedogenesis influenced its development. Therefore, this profile bears valuable imprints of climate, vegetation, land surface, and land use changes in this part of the Adriatic area for the time period covering the past 16 ka. The 4Ck horizon is a remnant of an A-C soil profile, whose incipient formation corresponds to a steppe-like palaeo-vegetation and a semi-humid to semi-arid palaeo-climate. The 3Btb horizon has blocky structure; common clay coatings and infillings that are related to the walls of channel macrovoids; increased CIA, Al/Si and Ba/Sr ratios due to the increase of the Al and clay contents; highest Fet, Fed, Mnt and Mnd values due to abundant redox concentrations; and specific clay mineralogy. Since the obtained age of the loess deposit (4Ck horizon) underlying the 3Btb horizon is 16.1 ± 1.3 ka (can be correlated to the Late Glacial Maximum, i.e., OIS-2), we find that the period of the Bolling-Allerod warming might have enabled the formation of the highly weathered 3Btb horizon within a Luvisol-like soil. After the period of surface stability, a period of forest decay and surface instability took place, resulting with the erosion of the Luvisol. The 3Btb horizon was then covered with a homogeneous loess material (whose deposition can presumably be related to the Younger Dryas period), inside of which the horizons 2C1 and 2C2 are recognized. Both these horizons are negligibly affected by pedogenesis and contain artefacts. The incipient soil formation in the upper part of the profile, along with the irregular lower boundary of the A horizon and the lithic discontinuity between the A horizon and the 2C1 horizon, points to the possibility of a very recent and minor aeolian deposition. However, one should not overlook the potential impacts of human activities and/or colluvial depositions on the properties of the A, 2C1, and 2C2 horizons.

A detailed pedocryostratigraphic scheme of the Late Pleistocene periglacial region of the East European Plain has been developed on the basis of study of the paleorelief, sediments, paleosols, and cryogenic horizons. OSL and 14C-dating of paleosols and sediments in Aleksandrov quarry and in other sections made it possible to substantiate this scheme and correlate it with analogous ones for different regions of Europe. The loess-paleosol sequence in Aleksandrov quarry (51º05'N, 36º08'E) does not have an analogous with respect to the completeness in the whole East European Plain. In the filling of paleobalka the Ryshkovo paleosol of the Mikulino interglacial (MIS 5e) is observed. Over this paleosol, the Valdai soil-sediment series (MIS 5d – MIS 2) is located. It includes four interstadial soils, two of them of the Early Valdai (Kukuevo and Streletsk ones), and two, sometimes three, of the Middle Valdai (Aleksandrov, Hydrouzel и Bryansk ones). The OSL date, 127 ± 8 ka BP, (beginning of MIS 5e) was obtained for a sample taken from the bottom of the Ryshkovo soil. The interglacial soil is overlain by the Seym layer formed mainly from destroyed and redeposited horizons of this soil. For the upper part of the Seym layer, OSL dates of 115 ± 7 ka BP and 112 ± 20 ka BP were obtained (MIS 5d). But the process of burial of Ryshkovo soil in the bottom of the paleobalka began at the end of the interglacial after a catastrophic forest fire. Large post-permafrost deformations - pseudomorphosis is confined to Selikhovodvor loess - MIS 4 (65 ± 8 ka BP). Two soils occurring between Seym and Selikhovodvor loesses: Kukuevo and Streletsk - Early Valdai (MIS 5c and MIS 5a). For Mlodat loess which separates those two soils (MIS 5b), OSL dates of 91 ± 1 and 89 ± 7 ka BP were obtained. For paleosols of Middle Valdai (MIS 3), 14C-dates were obtained: Aleksandrov (53.742 - 2.124 ka cal BP) and Bryansk soils (37.618 ± 0.668 ka cal BP). For Tuskar loess, which separates Alexandrov and Bryansk soils, OSL dates of 50 ± 3 and 51 ± 3 ka BP were obtained. The new stratigraphic scheme of Late Pleistocene agrees with the ideas of researchers from Eastern, Central, and Western Europe , which allows the following correlations. The identified paleosols correspond to the following intervals: Ryshkovo – Eemian interglacial (127-117 ka BP); Kukuevo to Amersfoort + Brørup – Saint-Germain 1 (105-95 ka BP); Streletsk – Odderade to Saint-Germain 2 (about 85-75 ka BP); Aleksandrov to Oerel (56-53 ka BP); Hydrouzel to Moershoofd – Poperinge (44-45 ka BP) and Hengelo (40-38 ka BP); and Bryansk (33-27 ka BP) to Stillfried B, Denekamp or Grand Bois interstadials. The reconstructed Late Pleistocene loess-paleosol sequence has the most similar structure with loess-paleosol sequences of Ukraine, with sequence Dolní Věstonice in Moravia (Czech Republik), Stillfried in Austria and Mainz-Weisenau in the Rhenish area (Germany), and other archives. This work was supported by RFBR, grant N19-29-05024 mk.

A high-resolution analysis of the Zmajevac loess-palaeosol sequence in East Croatia (Baranja) was performed with the purpose to get new insights into the palaeoenvironmental history during the last three glacial-interglacial cycles. The post-IR infrared stimulated luminescence signal of feldspar, stimulated at 290°C (thereafter pIRIR290) was used to establish a reliable chronological framework and revealed intensive sedimentation during (at least) the last 300 kyr, which was five times interrupted by climate optima resulting in the formation of soils (now palaeosols). The environmental magnetic measurements support the obtained luminescence chronology. Further chronological time control was reached by age modelling based on tie points from variations in frequency dependence of magnetic susceptibility and benthic δ18O variations from the LR04 stack of Lisiecki and Raymo (2005). The grain-size record provided information about the environmental conditions and dust accumulation. Additional palaeoenvironmental implications were provided by room temperature magnetic susceptibility and colourimetric analyses and revealed a continuously lower intensity of pedogenesis, coupled with constantly decreasing temperatures and precipitation from the oxygen isotope stage (OIS) 9 to the end of OIS 3. X-ray diffraction of the clay mineral fraction revealed chlorite, smectite and illitic material as dominant mineral phases. While clay minerals from loess are mostly detrital, smectite from palaeosols is partly of a pedogenic origin. The application of our multi-proxy approach, including relative and numerical dating techniques, provided new insights into a highly resolved terrestrial paleoenvironmental record of Eastern Croatia.

Loess-paleosol sequences (LPSs) are essential records for reconstructing Quaternary paleoenvironments. No previous study has provided numerical chronologies of loess in Lower Franconia, southern Germany; their chronostratigraphic assumptions have relied mainly on German (pedo)stratigraphic schemes. In this study, we provide for the first time a chronology for LPSs in Lower Franconia based on optically stimulated luminescence (OSL) dating using quartz and a comparison of K-feldspar (63–100 µm) and the polymineral fraction (4–11 µm). Our results show that all obtained ages are in stratigraphic order, ranging from Holocene to late Pleistocene, and in general confirm the former stratigraphical interpretations. A good agreement of the obtained ages is observed between both feldspar grain size fractions; they also agree well with the quartz OSL ages up to ∼50 ka. However, a marked difference between the growth pattern of the dose response curves and consequently different saturation characteristics of fine and coarse grains is found. Even though in our samples the discrepancy in ages is not very significant, we suggest the use of coarse-grained K-feldspar whenever possible in order to not be confronted with unknowns such as the mineral composition of the polymineral fraction., Löss-Paläoboden-Sequenzen sind wichtige Archive zur Rekonstruktion der quartären Umwelt. Bisher hat sich noch keine Arbeit mit der numerischen Chronologie mainfränkischer Lösse befasst; die bisherigen chronostratigraphischen Einordnungen haben ihren Ursprung in deutschen (pedo)stratigraphischen Schemata. In der vorliegenden Arbeit stellen wir erstmals eine auf optisch stimulierter Lumineszenz (OSL) basierende Chronologie für Löss-Paläoboden-Sequenzen in Mainfranken vor. Hierzu wurden Quarz und in vergleichender Weise sowohl K-Feldspat (63–100 µm) als auch die polymineralische Feinkornfraktion (4–11 µm) verwendet. Unsere Ergebnisse zeigen, dass alle gewonnenen Alter in stratigraphischer Reihenfolge sind, vom Holozän bis zum Spätpleistozän, und generell die früher angenommenen stratigraphischen Interpretationen stützen. Eine gute Altersübereinstimmung liegt für die beiden Feldspatfraktionen vor; die Alter stimmen weiterhin mit den Quarz-OSL-Altern bis 50 ka überein. Im Vergleich von Feldspat-Grobkorn und Feinkorn (polymineralische Fraktion) zeigt sich bei jedoch ein stark voneinander abweichendes Verhalten in den Wachstumsverläufen der Dose Response Curves und ein sich daraus ergebendes unterschiedliches Sättigungsverhalten. Auch wenn die Unterschiede für die hier vorliegenden Proben nicht übermäßig groß sind, so empfehlen wir, wenn immer möglich, die Verwendung von grobkörnigem K-Feldspat für die Datierung, um nicht mit möglichen Unbekannten, wie der Mineralzusammensetzung von polymineralischen Extrakten konfrontiert zu sein.

The aim of this work was to obtain a deeper understanding of the factors triggering geomorphological processes in the semi-arid mountain forest-steppe of the Khangai Mountains in central northern Mongolia. We hypothesized that the pattern of geomorphological processes in this region is strongly influenced by (i) the spatial distribution of aeolian sediments and (ii) forest fires. We further assumed that the spatial and functional relationships between these two geomorphological factors lead to various types of sediment-soil archives of landscape evolution in different relief positions. These different types of archives should have recorded different pieces of information, which might be combined into a reconstruction of the landscape evolution in this area. We intended to use these different archives to reconstruct the Holocene landscape evolution, and in particular, to identify the roles of aeolian sediment distribution and forest fires on the geomorphological processes that took place over the Holocene.The area is dominated by steppe vegetation. Only the north-facing slopes of the mountains, where reduced evapotranspiration leads to somewhat increased soil moisture, have forest. The bedrock on the slopes is overlain by Pleistocene periglacial slope deposits (PPSD), consisting of rock debris, which is mixed with fine sand in its upper part. These PPSD are widely covered by an aeolian sand sheet, which is usually more than one meter thick. IRSL ages indicate that the main deposition of these sediments took place 13-11 ka ago. Sediments at the toe slopes and on the valley bottom consist of layered, dark and lighter-colored, silty and sandy material with cryoturbation features. They apparently originate from soil material that has accumulated at the toe slopes and in the valleys by colluvial, fluvial and aeolian processes.On the slopes under forest, charcoal commonly occurs in the upper 20 cm of the soils and provides calibrated 14C ages of up to 2 ka. Calibrated 14C ages of charcoal and soil organic carbon of the sediments at the toe slopes are generally older (up to 4.4 ka). This difference suggests that the charcoal produced by earlier forest fires, together with the sediment in which it is embedded, has been washed from the upper and mid slopes down to the toe slopes and valleys. Charcoal of later fires is at least partially still in the place of its origin, on the slopes.Based on a set of 25 14C and 24 IRSL ages, we distinguish three main periods, i.e., (1) a period of extensive aeolian transport and deposition during the late glacial period, 16-11 ka ago, (2) a period of geomorphological stability from early until mid-Holocene, and (3) a period of enhanced aeolian, colluvial, and alluvial processes since 4.5 ka. The abundance of charcoal, indicating frequent forest fires during the late Holocene, points to a severe change of environmental conditions and geomorphological dynamics. It is not yet clear whether this change is due to more arid climate or human activities. Therefore, our further research will focus on distinguishing natural and human influence on the landscape evolution in Mongolia since the mid-Holocene.

Slope deposits with aeolian silt admixture are a widespread parent material of soils in the temperate zone but may be neglected when rates of soil production are quantified. The concept of periglacial cover beds differentiates slope deposits with or without aeolian silt admixture; yet there is a remaining debate on processes and the timing of their formation. A previous study done by us at Mt. Śleza, SW Poland, concluded that slope deposits with variable aeolian silt admixture, or its lack, have a significant influence on the pathway of soil formation. The present work builds upon this finding, by adding further granulometric and micromorphological data from three representative profiles along a toposequence, in order to refine our understanding of local slope deposits and soil formation. Additionally, seven numerical ages using luminescence dating provide a chronological framework for our reconstructions and allow linking the forming processes of these pedosedimentary records to regional palaeoenvironmental conditions. The oldest aeolian deposits are of Middle Pleistocene age (>280 ± 19 ka) with interlayered palaeosol (marine isotope stage [MIS] 9 or older). Late Pleistocene slope deposits encompass the maximum loess thickness and are dated to MIS 2. Luminescence ages from the upper layers indicate shallow reworking, which we tentatively correlate to the Younger Dryas (YD). Two profiles with thick loess mantles have strong clay illuviation features, presumably formed during the Holocene. However, weak clay illuviation in the third profile with a thin loess mantle (having an age of YD) over granite regolith seems to have occurred before the Holocene, as only fragmented clay coatings (probably MIS 2 pedogenesis) could be found.

This study provides a detailed geochemical record of one of the best studied loess-paleosol sequences (LPS) in Hungary covering Marine Isotope Stage (MIS) 6 to MIS 2. Suttő is situated in the northwestern Carpathian Basin at the transition between oceanic and continental climate. We investigated weathering intensity, dust provenance and sedimentation dynamics by high-resolution X-ray fluorescence (XRF) scanning of discrete samples in comparison with quantitative XRF and other published proxy data such as grain-size, magnetic susceptibility and micromorphology. Multivariate statistics unravel pedogenesis in terms of decalcification and grain-size dynamics as processes controlling the elemental composition. Furthermore, high-resolution chemostratigraphy indicates geochemical homogeneity for mature MIS 5 paleosols and the modern soil. Together with the A-CN-K plot providing no hint for K-feldspar weathering, semi-arid continental paleoenvironmental conditions are considered as prevailing. Dust provenance is studied by geochemical reference literature data from potential ultimate dust source areas, Th/metal ratios and comparison with the composition of the upper continental crust (UCC). Results indicate a felsic rock composition and a stable dust source, albeit immediate (adjacent Danube floodplains) and ultimate dust sources (surrounding mountain belts) need to be distinguished. According to the Sr-K-Rb plot, the Austroalpine cover nappes area northwest of Suttő might be the dominant ultimate dust source. The weathering-resistant elements Al, Ti and Zr as well as Zr/metal ratios indicate Zr addition and thus strongest sediment sorting and/or recycling during MIS 6. Since Al, Ti and Zr show minimal correlations with grain-size, we suggest a cascade-alike transport pathway from ultimate source to sink involving multiple sediment recycling and sorting cycles in both fluvial and eolian domains. Therefore, this study highlights how high-resolution qualitative geochemical data contributes to a better understanding of paleoenvironmental and sedimentation dynamics at LPS. Application of such a versatile geochemical screening tool is of broad interest to the scientific community working on (terrestrial) paleoenvironmental archives that are commonly discretely sampled.

Stratified periglacial sediments extensively cover the slopes of central European low mountain areas. Periglacial cover beds and loess-like sediments as most abundant strata influence many near-surface processes, forming an important component of the Earth's critical zone. The present study focusses on the analysis of a complex sequence of periglacial slope deposits with multiple intermediate layers and intercalated slope wash sediments in order to determine and date periods of intermediate layer formation. Since luminescence dating often provides inconsistent data for cover beds, there is need to reconsider the numerical dating strategy. This study hence places stronger emphasis on numerical dating of interbedded, sufficiently bleached slope wash sediments. The gained OSL-ages are more reliable and consistent and thus, provide a temporal framework for relative dating of intermediate layer formation cycles. In combination with paleosol relics the numerical ages allowed a chronostratigraphic interpretation of Late Pleistocene paleoenvironmental dynamics and slope evolution. Our findings not only prove multiple phases of intermediate layer formation in the study area during the last glacial period but also enabled the correlation of single intermediate layers with specific time spans, including Early and Middle Weichselian as well as the Late Glacial. Remnants of the Eemian soil in the studied sequence even indicate a Saalian age for the lowermost intermediate layer. The present study shows that luminescence dating of intercalated slope wash deposits instead of cover beds is a promising numerical dating strategy for the chronostratigraphic interpretation of cover bed sequences. The findings further illustrate that complex, fanned out periglacial sediment sequences form despite their scarcity important paleoenvironmental archives for Late Pleistocene periglacial landscape dynamics in central European low mountain areas.

In this study, luminescence dating of core sediments from the North Bohai Coast (China) was applied to provide a high-resolution chronological constraint, on a better understanding of the Holocene marine-terrestrial interaction. The studied sedimentary sequence contains a terrigenous deposit, a transgressive deposit and a prograding deltaic succession; all are believed to have formed during the late Pleistocene. To establish a reliable luminescence chronology, the luminescence signals of ten samples were investigated in order to quantify the degree of bleaching. This approach involved the use of quartz OSL, K-feldspar infrared stimulated luminescence (IRSL) and post-IR IRSL (pIRIR) ages. The resulting data were then compared with radiocarbon ages. The quartz OSL signals were well-bleached for all the samples, and the feldspar pIRIR150 and pIRIR225 signals yielded reliable ages for the pre-Holocene deposits but overestimated ages for late Holocene deposits (

In southern Eurasia recurrent phases of aridization, dust source extension and enhanced Aeolian sedimentation alternated with moister intervals, promoting reduced deflation areas and dust accumulation in the context of late Pleistocene climate changes. Weathering and soil forming intensity in this greater region are, hence, mainly governed by fluctuations in the balance between dust supply and moisture availability. Among the hitherto known sections, the Toshan loess-soil sequence (LPS) represents a key site due to the quality of the record and the multitude of available data giving detailed insights into the timing and magnitude of dust accumulation and soil formation of the region. To elucidate these dynamics for much of the past 130.000 years bulk mineralogical and geochemical data are presented supplemented by a high resolution magnetic susceptibility record and by the results of a detailed micromorphological study of loess at Toshan. The last interglacial Luvisol/Phaeozem-like (∼MIS 5e) and the early glacial interstadial steppic palaeosols (∼MIS 5 c and a) are characterized by gradually increasing grain-size and decreasing degrees in decomposition of micaceous and mafic minerals. Pronounced feldspar weathering is detected in the last interglacial and modern soils only, which formed under reduced or absent dust deposition on penultimate and last glacial loess, respectively (postsedimentary). The overall pedosedimentary conditions correspond to large scale trends of increasing drought, dust accumulation and wind strength in southern Eurasia in relation to decreasing moisture availability towards the early Pleniglacial (∼MIS 4), causing soil formation under ongoing dust deposition (synsedimentary). Similar intervals of synsedimentary soil formation are recorded during the interglacial/interstadial-stadial transitions of the early glacial and during pleniglacial (∼MIS 4 to 2) interstadials. The latter are marked by gradual increases in magnetic susceptibility, colour and decreasing texture. Conversely, silicate weathering could not be detected, suggesting that grain-size fluctuations are a primary feature. Thus, windy and arid pleniglacial conditions in southern Eurasia were interrupted by intermittent phases of synsedimentary soil formation, in response to short-lived and relatively moist interstadials. Although the interrelation of these incipient soils, throughout southern Eurasia is afflicted with considerable restrictions, the oscillatory pattern of the Toshan LPS bears great similarity with millennial-scale oscillations recorded in limnic archives of western Asia.

Thin loess deposits are widespread soil parent materials and important archives for paleoenvironmental reconstruction. The origin of loess in SW Poland is attributed to the Great Odra Valley (GOV), following the general concept that large rivers play a major role in regional silt supply. Yet, the precise provenance (glacier sources and/or local rocks) of silts, possibly deflated from dry GOV braided riverbeds, is not clear. Our study of thin and thick loess mantles in SW Poland for the first time indicates the provenance of thin loess based on mineralogical (MLA-SEM) and isotopic analyses (143Nd/144Nd, 87Sr/86Sr). Luminescence ages of five localities point to thin loess mantle formation during and shortly (23.0 to 17.7 ka yr) after the Last Glacial Maximum (LGM). Our isotopic data indicate that thin loess deposits in SW Poland are the mixtures of two main components – local Sudetic and Scandinavian, the latter delivered by the Fennoscandian ice sheet (FIS). Also, detailed analyses of heavy minerals show that a single mineral (e.g., hornblende) may come from both Sudetic and Scandinavian sources. This research highlights the role of the (Pleistocene) GOV in collecting and homogenizing materials, while supplying the region with fine particles to be deflated by paleowinds from open surfaces. Anomalies in mineralogy and isotopic composition are connected with influence of Sudetic mountain rivers and locally blowing silt material by katabatic winds. Regional grain size differentiation of thin loess mantles explains transport distance and altitude.

Arid central Asia (ACA) is one of the largest arid (desert) areas in the world, and its climate is dominated by the westerlies. In this study, we examined sand dune evolution from the Bayanbulak Basin in the Tian Shan (Xinjiang, NW China), aiming to infer the Holocene moisture history of the ACA. Combined with stratigraphic observation and environmental proxies analysis (grain size, magnetic susceptibility and total organic content), large numbers of luminescence ages from multiple sites (eight sections, 79 samples) were applied to reconstruct the evolution of the sand dune accumulation in the study basin. The overall results imply very dry conditions characterized by sand dune accumulation at ∼12–6.5 ka, a wet interval between ∼6.5 and 0.8 ka when soil formation occurred, and decreased moisture during the last 0.8 ka. This moisture variation pattern is generally consistent with that inferred from many lacustrine records in the core zone of ACA, suggesting a widespread dry period in the early-to-middle Holocene and relatively wet middle-to-late Holocene. Thus, the moisture history derived from the current sand dune system contrasts with that in Asian monsoon areas, which are characterized by a strong monsoon (high precipitation) in the early and mid-Holocene and a weak monsoon (low precipitation and dry climate) during the late Holocene. Our results strongly suggest that the winter solar insolation and the external boundary conditions such as atmospheric CO2 concentration, ice sheets, and meltwater fluxes, have been major influential factors triggering the Holocene moisture evolution in the core zone of ACA.

The Heidelberg Basin (HDB) hosts one of the thickest Quaternary sediment successions in central Europe. To establish a reliable Middle and Upper Pleistocene chronology for a recently drilled core from the depocentre of the Heidelberg Basin, we applied multiple luminescence dating approaches, including quartz optically stimulated luminescence (OSL), two feldspar post-IR IRSL protocols using second IR stimulation temperatures of 225 °C (pIRIR225) and 290 °C (pIRIR290), and two fading correction models. Relatively high anomalous fading was observed for both the pIRIR225 and pIRIR290 signals, with mean fading rates of 2.13±0.27 and 2.08±0.49%/decade, respectively. Poor dose recovery behaviour of the pIRIR290 signal suggests that the pIRIR290 ages are not reliable. The comparison of two fading correction methods for the K-feldspar ages indicates that the correction method proposed by Kars et al. (2008) Radiation Measurements 43, 786, yields reliable ages, whereas the dose-rate correction method proposed by Lamothe et al. (2003) Radiation Measurements 37, 493, does not. A chronology for the HDB is established using the quartz ages and reliable fading corrected feldspar pIRIR225 ages. Our chronology shows that the sediments in the upper Mannheim Formation were deposited during Marine Isotope Stage (MIS) 4 (c. 70 ka), constrained by two quartz ages in the upper 20 m of the core. Four fading corrected pIRIR225 ages of c. 400 ka show that the upper Ludwigshafen Formation was deposited during MIS 12–11, correlated with the Elsterian-Holsteinian stage. Two ages of 491±76 and 487±79 ka indicate that the Middle and Upper Ludwigshafen Formation were probably deposited during the Cromerian Complex. This luminescence chronology is consistent with palynological results. It also indicates that the IR-RF ages reported earlier are probably underestimated due to anomalous fading.

International audience; Beachrocks represent a significant paleo-environmental proxy because they can record both the vertical and the horizontal evolution of the shoreline. They have often been used to assess Holocene shoreline evolution and crustally induced Relative Sea-Level (RSL) changes in the Mediterranean Sea. In this paper, we used submerged beachrocks from Paros and Naxos Islands (Aegean Sea, Greece) to reconstruct the shoreline modification and provide new insights on the RSL evolution in central Cyclades. Paros and Naxos Islands are of great importance in terms of archaeological evidence of coastal occupation. However, the evolution of their coastlines was seldom explored. In this study, we coupled detailed underwater surveys, analysis of aerial photogrammetry, microstratigraphic analysis and luminescence dating to study beachrock outcrops found down to about 6 m below the present sea-level. We, then, spatially and chronologically constrained some major palaeogeographical changes of a number of coastal sectors of the two islands. Furthermore, the multiple analyses of beachrocks, sediment coring and archaeological data suggested that RSL rose by at least 3.8 m in the last 4.0 ka and that RSL variation in the last 2.0 ka did not exceed 2 m with respect to the present mean sea level.

Here we present a multi-proxy investigation of the Klein Klutz Hoved (KKH) coastal cliff section in northeastern Germany, involving lithofacies analysis, micromorphology, micropalaeontology, palynology and luminescence dating of quartz and feldspar. We subdivide the local stratigraphy into three depositional phases. (i) Following a Saalian advance (MIS 6) of the Scandinavian Ice Sheet, the penultimate deglaciation (Termination II) at the site occurred between c. 139 and 134 ka, leading to the establishment of a braided river system and lacustrine basins under arctic-subarctic climate conditions. (ii) In the initial phase of the Eemian interglacial lacustrine deposits were formed, containing warm-water ostracods and a pollen spectrum indicating gradual expansion of woodlands eventually containing thermophile deciduous forest elements. A correlation of the local pollen assemblages with Eemian reference records from central Europe suggests that fewer than 750 years of the last interglacial period are preserved at KKH. The occurrence of brackish ostracods dates the onset of the Eemian marine transgression at the section at c. 300–750 years after the beginning of the last interglacial period. (iii) Directly above the Eemian record a ~10-m-thick sedimentary succession of MIS 2 age was deposited, implying a significant hiatus of c. 90 ka encompassing the time from middle and upper MIS 5e to late MIS 3. During the Late Weichselian, KKH featured a depositional shift from (glacio-)lacustrine to subglacial to recessional terminoglacial facies, with the first documented Weichselian ice advance post-dating 20±2 ka. Overall, the KKH section represents an exceptional sedimentary archive for palaeoenvironmental reconstructions, covering the period from the Saalian glaciation and subsequent Termination II to the early Eemian and Late Weichselian. The results refine the existing palaeogeographical and geochronological models of the late Quaternary history in the southwestern Baltic Sea area and allow correlations with other reference records in a wider area.

A multi-proxy study, including palaeoecological, lithological, geochemical and geochronological methods, has been carried out on the Garding-2 research drill core in the German North Sea coastal area at Garding, in Schleswig-Holstein to investigate the palaeoenvironmental and palaeoclimatic evolution and the Quaternary stratigraphy for a broader correlation of Quaternary sequences of formerly glaciated and non-glaciated areas and with Marine Isotope Stages (MIS). The 240 m long sequence, composed mainly of fine- and coarse-grained fluvial–shallow marine sediments intercalated by muddy–peaty deposits, reveals interglacial–glacial cycles. Based on palynological and lithological findings, the Pliocene- Pleistocene transition lies at 182.87 m below the surface. It is succeeded by Praetiglian deposits and sediments of the Waalian and Bavelian Complex. The termination of the probably second or third Cromerian interglacial is marked by the development of mixed-deciduous forest and the last occurrence of Tsuga at 119.50 m depth. At about 109.45–96.00 m, another pre-Elsterian interglacial period is found and tentatively correlated with the Bilshausen Interglacial. The overlying glacigenic sediments between about 89.00 and 82.00 m are assigned to the Elsterian. An unconformity occurs below 80.29 m, at the base of late Holsteinian deposits, which are succeeded by sediments of the subsequent Fuhne cold period between 79.20 and 73.00 m. These deposits are unconformably overlaid by the Drenthian till at 73.00–71.00 m. A single sample of the late Eemian Interglacial is found at 69.25 m and overlain by the Weichselian glaciofluvial sediments. Middle– late Holocene sediments occur from 20 m depth upwards, following a hiatus that is caused by the early Holocene transgression. Optically stimulated luminescence and radio carbon dating results are in accordance (Zhang et al. 2014) and show that these sediments were deposited between around 8.3 and 1.5 ka.

The Northern Iranian loess profiles host important information on Quaternary climate and palaeoenvironmental changes in the region. They build an important link between the Eurasian loess belt and European and Central Asian archives. Due to a climatic gradient with decreasing precipitation from the west to the east and from the south to the north, loess-palaeosol sequences formed synchronously under different climatic conditions can be studied over short distance in the Iranian Caspian Lowland. The Agh Band profile is located in the so called Iranian “Loess Plateau”, a semi-arid region with 200–350 mm annual precipitation. The loess deposits at Agh Band reach a thickness of >60 m. An about 50 m thick step-profile was prepared and the litho/pedostratigraphy was investigated. Samples for laser-diffractometry grain-size measurements were taken every 2 cm. The magnetic susceptibility was measured in 4 cm intervals and the CaCO3-content in 8 cm intervals. To establish a chronological framework a pIRIR290 luminescence dating approach was applied to the 4–11 μm polymineral fraction. The results show that the Agh Band profile yields a climate archive reaching from MIS 7 to MIS 2. Several chronological hiatuses of some 10 ka show that periods of intense loess accumulation were interrupted by phases of only minor loess sedimentation and/or erosion. The Agh Band profile is subdivided by several shifts in grain-size distribution. The coarsening- and fining up trends correlate with increasing and decreasing wind-velocity, respectively. In the central part of the Agh Band loess sequence a weakly developed palaeosol is preserved which was developed at around 80 ka. Furthermore, the loess deposits formed from about 100 ka to 60 ka ago show banded structures. A pedocomplex including two well-developed palaeosols consisting of Bw(y) horizons and a CB-horizon as well as intercalated loess can be found in the lower part of the sequence also evidenced by the increased values of magnetic susceptibility. The corresponding luminescence age estimates indicate that the palaeosols represent a period of increased humidity and landscape stability during late MIS 7 and MIS 6. Hence, in the Agh Band loess, various changes in the palaeo-sedimentary system, triggered by changes in climate can be observed. This yields important information on the sensitive response of sedimentary systems and landscapes within semi-arid regions to shifts in moisture and possibly temperature.

The timing of the formation of extensively distributed sand dunes in the Bohai coastal area and its forcing factors are poorly understood. In this study, the chronology of a well-preserved sand dune located in Panjin Forest Park (PJ) in the Lower Liao Plain (LLP) is investigated using quartz optically stimulated luminescence (OSL) and K-feldspar postinfrared (IR) infrared stimulated luminescence (IRSL) (pIRIR) dating. For the pIRIR measurements, the combination of preheating at 180°C and pIRIR stimulation at 150°C (pIRIR150) is exploited. The quartz results show that the sand dune accumulated from c. 120 a (1890 AD) to c. 70 a (1940 AD) before present, and the underlying sandy soil sediments deposited from c. 5.0 ka to c. 0.13 ka as marsh sediment after the sea level highstand since the mid-Holocene. From the evidence in historical coastline records, the PJ sand dune is an inland sand dune and not a coastal sand dune. Based on further information of climate and temperature change after the Little Ice Age (LIA) and human activity in northeastern China, we conclude that the PJ sand dune accumulation was very likely impacted by the immigrants and land reclamation at the end of Qing dynasty. The fading corrected IR50 ages, the apparent and fading corrected pIRIR150 ages are consistent with quartz ages for two sandy soil samples but overestimate those for six sand samples. The overestimation of the feldspar ages is derived from the residual signal which has not been bleached before burial. The offset obtained from the difference between the quartz OSL and the feldspar pIRIR150 ages are ~20–160 a (predicted residual dose: ~0.08–0.60 Gy), whereas the measured residual dose after bleaching 4 h in a solar simulator yielded age overestimation of ~10–40 a (~0.05–0.16 Gy). The age discrepancy calculated from the predicted residual was larger than those obtained from the laboratory measured residuals. We conclude that the pIRIR150 of aeolian sediment is applicable for samples older than ~1000 years where the effect of the residual dose become negligible.

The loess deposits in northern Iran are located in a key region connected to the European and central Asian loess belts. However, the lack of previous detailed sedimentological and palaeoclimatic studies of the Pleistocene loess in the region limits our understanding of the nature of ancient aeolian processes and loess history in the mid-latitudes of Euro-Asia as a whole. Here, we present the results of grain-size analyses of the Pleistocene loess from the so-called Iranian Loess Plateau (ILP) in northern Iran. Our results reveal that the grain-size distribution of the deposits is characterized by trimodal and bimodal distributions, comprising a dominant well-sorted coarse dust component (ca. 7–75 μm), a small poorly-sorted fine dust component (ca. 2–7 μm), and a minor pedogenic clay component (

In Northern Iran mean annual precipitation and vegetation vary significantly over short distance from a semi-desert to a forest biome. These ecosystems likely responded differently on past climate changes. We here aim at i) testing the applicability of biomarkers (leave-derived n-alkanes, their stable carbon isotope composition, and C and N stable isotopes of soil organic matter) in loess-derived soils to identify and differentiate past ecosystems, and ii) elucidating the variability of these biomarkers in palaeosols. We sampled modern topsoils and palaeosol horizons within an ecological gradient covering a range in mean annual precipitation from 200 to 750 mm from the Kopet Dag semi-desert to the Hyrcanian forest on the footslopes of the Alborz Mountains. C org , N, δ 13 C org , δ 15 N, and n-alkanes (and their compound-specific δ 13 C) were analyzed to characterize organic matter composition and sources. In modern soils a systematic increase in C org and N was observed with precipitation. The δ 15 N decreased from about 6 to 4‰ pointing to systematically more degraded organic matter in semi-desert soils. The leave-wax specific ratio of (nC 31 + nC 33 )/(nC 27 + nC 29 )-n-alkanes was >1 for semi-desert soils and 13 C org showed no systematic trend in this gradient. In loess and palaeosol profiles, contents of C org , N and n-alkanes dropped about a factor 10 compared to modern soils. The n-alkane ratio and δ 15 N ratios remained on comparable levels as did the compound-specific δ 13 C in n-alkanes. However, bulk δ 13 C org was altered from about −27 in modern soil to −23‰ in loess-palaeosols. Systematically higher C org and N values were observed in palaeo-topsoils compared to loess and subsoil. Stable C isotopes varied rather unsystematically within loess-palaeosol sequences, while δ 15 N revealed trends within palaeosols, however, in contrasting directions with palaesol depth. The (temporal) average n-alkane ratio for all palaeosol horizons of one site systematically followed the modern precipitation gradient indicating that in all periods of soil formation a climatic gradient developed.

Loess-palaeosol sequences are highly resolved archives for palaeoenvironmental reconstruction and build an important link to correlate European and Central Asian loess sequences. For the loess palaeosol sequence at Toshan, Northern Iran, a luminescence-based chronological framework was established. The timing of dust accumulation and soil formation was investigated and thereby information on changes in palaeoenvironmental conditions in the region obtained. For luminescence dating, the 4e11 mm grain size fraction was used and the pIRIR290 approach was applied to polyminerals. Tests concerning bleachability, dose recovery and anomalous fading were conducted. The results show that residual doses have only minor influence on the determination of the equivalent dose. The Eemian (MIS 5e) soil seems to be preserved but a chronological classification based on luminescence ages for this soil remains difficult. The pIRIR290 age estimates from the lower part of the profile range from 104 ± 9t o 127± 8 ka. Lumi- nescence ages from the central profile-part point to an increase in dust accumulation starting around the MIS 4/MIS 3 transition. Furthermore, a chronological framework for interstadial soils was developed indicating e.g. soil formation at around 40 ka during MIS 3 and 26 ka during MIS 2. The top part of the profile was dated to about 22 ka. The age estimates show that the Toshan loess profile is a highly resolved loess record providing a valuable climate archive for the last glacialeinterglacial cycle reflecting several climatic shifts represented by dust accumulation or enhanced degrees of soil formation (stadials and interstadials).

The loess deposits in Iran are a valuable archive of regional paleoclimatic and paleoenvironmental information. Extensive sedimentological and chronological studies have been carried out on the middle to upper Pleistocene loess successions during the past decades, but there is an absence of comparable research in the older loess deposits. Recently, a 19-m-thick loess-paleosol sequence was discovered in the central Iranian Loess Plateau (ILP), which was paleomagnetically-dated to ∼2.4–1.8 Ma and thus represents by far the oldest loess known in northern Iran. Here, we present the results of a detailed micromorphological investigation of these lower Pleistocene loess-paleosol sequences (“red sequence”) from the ILP. Our main findings are as follows: 1) The Agh Band red sequence deposits are an extremely thick soil complex comprising paleosols in different stages of development; 2) the micromorphological index of soil development (MISECA) suggests that the moderately- and well-developed paleosols in the red sequence formed in an environment with mean annual precipitation ranging from around 450 to 650 mm, respectively; and 3) MISECA suggests that the red sequence formed under a semi-arid to sub-humid climate and thus under wetter and more favorable conditions than the overlying late Pleistocene loess and modern soils.