Middle Pleistocene Loess Research Articles

Multi-method study of the Middle Pleistocene loess–palaeosol sequence of Köndringen, SW Germany

Abstract. Loess–palaeosol sequences (LPSs) remain poorly investigated in the southern part of the Upper Rhine Graben but represent an important element to understand the environmental context controlling sediment dynamics in the area. A multi-method approach applied to the LPS at Köndringen reveals that its formation occurred during several glacial–interglacial cycles. Field observations, as well as colour, grain size, magnetic susceptibility, organic carbon, and carbonate content measured in three profiles at 5 cm resolution, provide detailed stratigraphical information. Only minor parts of the LPS are made up of loess sediment, whereas the major parts are polygenetic palaeosols and pedosediments of varying development that are partly intersected, testifying to a complex local geomorphic evolution. The geochronological framework is based on 10 cm resolution infrared-stimulated luminescence (IRSL) screening combined with 18 multi-elevated-temperature post-IR IRSL ages. The luminescence ages indicate that two polygenetic, truncated Luvisols formed during marine isotope stages (MISs) 9(–7?) and MIS 5e, whereas unaltered loess units correspond to the last glacial (MISs 5d–2) and MIS 8. The channel-like structure containing the two truncated Luvisols cuts into > 2 m thick pedosediments apparently deposited during MIS 12. At the bottom of the LPS, a horizon with massive carbonate concretions (loess dolls) occurs, which may correspond to at least one older interglacial.

Distribution feature and development characteristics of geohazards in Wudu district, Gansu province, Northwest China

BackgroundThe study area located at southeast Gansu, China, has long been afflicted by the intense occurrence of geohazards. The study area is characterized by interleaving terrain of precipitous mountains and valley basins, abundant precipitation, and complicated geological setting. In this work, 1144 geohazards including 759 landslides, 281 debris flows, and 104 collapse were presented and their types were categorized in detail. Then, the distribution of geohazards were analyzed and the controlling role of hazard-inducing environment and triggering factors on geohazards were preliminary presented.ResultsIn this work, correlation analysis between geohazards and geological, topographical, and geomorphological context was conducted. Concave slopes with height smaller than 200 m and slope gradient between 21° and 40° is the favorable topographic feature for landslide occurrence and the predominant slope aspects of landslides are southwest, south, west, and southeast. Collapse generally occurs in slope with gradient larger than 45°. Valleys with valley gradient less than 400‰, valley height between 100 and 500 m, and watershed area of 1–10 km2 register the largest percentage and the most favorable slope gradient for the supply of solid source at the debris flow source area is 25°–45°. The preferable strata for geohazards (landslide, collapse and debris flow) are Middle and upper Pleistocene loess, Holocene diluvium, Silurian phyllite and slate, Neogene mudstone, and Devonian schist and gneiss, and most geohazards occurred in tectonic erosional middle altitude mountain, tectonic erosional high-middle altitude mountain, tectonic erosional-diluvial planation surface. In addition, the controlling role of triggering factors, i.e., precipitation, earthquake, and human engineering activity was discussed and described in this work.ConclusionGeohazards in the study area are synthetically controlled by the hazard-inducing environment and triggering factors. The complicated sliding-prone strata and steep topography resulted from strong tectonic movement provides a favorable basis for the development and formation of geohazards. Heavy rainfall, strong seismic motion, and human engineering activity are the main triggering factors for geohazard occurrence.

A huge Pachycrocuta from the middle pleistocene loess in Luoning County, central China, and the evolution of mandible within Pliocrocuta-Pachycrocuta lineage

ABSTRACT The giant hyena Pachycrocuta is one of the iconic components in Eurasia Pleistocene faunas. This genus largely went extinct near the Early-Middle Pleistocene boundary in Europe, but continued to flourish till the early Middle Pleistocene in eastern Asia. However, the Middle Pleistocene Pachycrocuta in eastern Asia is only well represented in Loc. 1, 9 and 13 of Zhoukoudian, and the geographic variation is unknown. Here, a complete mandible is reported from the Middle Pleistocene loess in Luoning, Henan Province, central China. The mandible is similar to that of Pachycrocuta from Zhoukoudian in dental morphology, but is markedly larger, being the largest Pachycrocuta known (the estimated skull total length reaches 385 mm, and the estimated body mass is 150.3 kg). It also displays several unique mandibular traits, e.g., strongly curved toothrow, and elevated condyle. This suggests the presence of geographic or chronological differences between the populations of Pachycrocuta across Asia during the Middle Pleistocene. A gradually increasing depth is observed in the Pliocrocuta-Pachycrocuta lineage during its evolution, until its final extinction.

Provenance and Climatic Implications of the Middle-Pleistocene Loess Deposit, Southern China

The middle-Pleistocene Xiashu loess deposit in the lower reaches of the Yangtze River (LRYR), southern China, may yield evidence with significant climatic and environmental significance. However, its provenance remains controversial. In this study, grain size analysis, and quartz grain surface microtextural and morphological observations, enabled comparison of the provenance of loess in the LRYR with those on the Loess Plateau in northern China. The results show that the grain size characteristics of the Xiashu loess do not follow the coarse-fine NW-SE trend in northern China, and the surface microtextures of the quartz grains in the Xiashu loess are distinctly different from those on the Loess Plateau in northern China, indicating that the loess deposits in the two regions have different provenances. The Gobi Desert in inland northwestern China are not considered as the primary provenance of the Xiashu loess. Instead, the adjacent floodplains in the LRYR, the alluvial plains of the Huai River and the Yellow River to the north during glacial periods are suggested as the dominant source materials for the Xiashu loess. Under the background of middle-Pleistocene climate transition (MPT), regional aridity and a strengthened east Asian winter monsoon (driven by global cooling and the rapid uplift of the Tibetan Plateau) were considered as the primary drivers for the development of the Xiashu loess. The sustained eolian loess accumulation represent a regional response of the northern subtropical area of southern China to the MPT global cooling event at around 0.9 Ma.

The last 750 ka in loess–palaeosol sequences from northern France: environmental background and dating of the western European Palaeolithic

ABSTRACTThis study presents an overview of Middle Pleistocene loess–palaeosol sequences (LPS) in northern France and discusses the palaeoclimatic significance of the pedosedimentary record in the context of western European LPS and of global climatic cycles for the last 750 ka. In this area, the oldest loess deposits (early Middle Pleistocene) are preserved in sedimentary traps (leeward scarps of fluvial terraces and dissolution sinkholes). They result from local deflation processes reworking Pleistocene sandy fluvial deposits or relicts of Tertiary sands. A large extension of typical calcareous loess over the landscape, the Loess Revolution, is then observed during MIS 6, with heavy mineral assemblages testifying to long‐distance transport from the polar desert area of the dried eastern Channel. A correlation scheme is proposed between the global records of northern France in continental environments and both global palaeoclimatic records and other main western European LPS. After 30 years of research, northern France LPS stand as a fundamental archive of the impact of interglacial–glacial climatic cycles as well as millennial events. Finally, these works provide a robust chronoclimatic framework for the study of the western European Late Acheulean and Middle Palaeolithic and for the relative dating of the various fluvial terraces that they fossilise.

Middle and Late Pleistocene loess of the Western Ciscaucasia: Stratigraphy, lithology and composition

Due to the high preservation of the loess series and the availability of coastal outcrop sections loess cover of Western Ciscaucasia has ample opportunities for spatial paleogeographical reconstructions for the Middle and Late Pleistocene. Currently, the level of knowledge on the structure and composition of the loess-paleosol sequences of Western Ciscaucasia remains unequal. The Azov coast is studied in more detail in comparison with the inner part of the region. The structure and composition of the loess-paleosol sequences of different parts of Western Ciscaucasia (the Sea of Azov coast and western macroslope of the Stavropol Upland) for the Middle and Late Pleistocene are compared. Comparison of the key sections are based on litho- and pedostratigraphy, magnetic susceptibility, grain size, elemental and mineral composition, and luminescence dating. Recent results of luminescence dating allowed correcting the structure of the Mezin pedocomplex (S1). It was found out that this pedocomplex includes three phases of soil formation (S1SS1, S1SS2, S1SS3), which approximately correspond to the warm stages of marine isotope stage 5 (MIS 5) – 5a, 5c, 5e. In all sections, a clear trend towards an increase in the accumulation rates over the last three climatic macrocycles is observed. The last interglacial-glacial macrocycle (MISs 2–5) is characterized by the most significant increase in average accumulation rates, which were ∼1.8 times higher compared to MISs 6–7 and ∼2.3 times higher than during the MISs 8–9. A likely reason for the regional increase in the average dust accumulation rate was the directional increase in climate aridity. The patterns of the spatial distribution of the loess thickness and material composition indicate that the main source of aeolian dust is situated in the east. We suppose that the main sources of dust are sand masses of the alluvial plains of Lover Volga, Terek, Kuma and Kura rivers in the Caspian lowland. The Lower Don sandy province is reconstructed to be a secondary source. Dust is blown from the sandy terraces of the Don, and in the past - from the Don deltas, during the period when the Sea of Azov dried up.

Engineering-geological characteristics of the sediments of the loess-palaeosol sequence of the key section Proniatyn (Podolian Upland)

The Proniatyn key section represents the loess-palaeosol sequence of the Upper and partially Middle Pleistocene of the Podolian Upland. A detailed description of the section is given, as well as the engineering-geological characteristics of the sediments of the loess-palaeosol sequence Proniatyn, which is quite well stratified. There are two horizons of the Upper Pleistocene loess and the upper horizon of the Middle Pleistocene loess have been clearly distinguished. The key section presents the Dubno (MIS 3) fossil soil, the Horokhiv fossil pedocomplex (MIS 5), as well as the well-developed deluvial-solifluction sediments over the Horokhiv pedocomplex, which contain a large number of redeposited Middle Palaeolithic artifacts. The engineering and geological features of sediments of the loess-palaeosol sequence Proniatyn have been studied in detail and compared with the characteristics of the corresponding horizons of the loess-palaeosol sequences of a number of sections of the Podolian and Volhynian Uplands. It is established, in particular, that in many aspects the loess-palaeosol sequence of Proniatyn key section is closer to the characteristics of sediments of the loess-palaeosol sequences of the Podolian Upland. The importance of studying the Proniatyn key section is enhanced by the fact that it is associated with the Middle Palaeolithic site, and in the structure of the Horokhiv fossil pedocomplex there are all sub-horizons of MIS 5. Furthermore, it contains a geophysical Blake event. Therefore, it is confirmed that the Proniatyn key section is an important stratigraphic benchmark of the Pleistocene of Podolian Upland. Key words: loess-palaeosol sequences, key section, Pleistocene, engineering-geological characteristics, solifluction, Palaeolithic.

Інженерно-геологічна характеристика порід лесово-ґрунтової серії опорного розрізу Лисогора (Подільська височина)

The Lysohora key section is one of the most complete and interesting sections of the loess-palaeosol sequence of the eastern part of Podolian Upland. This is the area where the Pleistocene loess-palaeosol sequence was deposited directly on the rocks of Precambrian crystalline shield, its weathered part (eluvium). The value of engineering-geological research of the section is increasing due to the fact that it is located near the city of Vinnytsia, which has been intensively built up in recent years. We emphasize that in this section Upper Pleistocene loesses play a minor role. The value of the Middle Pleistocene loesses, which are generally poorly studied, is abruptly growing. The Lysohora section was sampled. Above 30 monoliths were taken with the purpose of studying the engineering-geological characteristics of the sediments. Among them are grain size distribution, natural moisture content, plasticity index, soil density, porosity coefficient, subsidence, angle of internal friction, specific cohesion, deformation modulus, chemical composition of aqueous extract, humus content, CaCO3 content, etc. The results of the exploration of the loess-palaeosol sequence properties are correlated with the corresponding stratigraphic horizons of the other sections of Podolian Upland. Besides the main section, which was described in a pit, two additional cuts were studied: one on the Korshiv palaeosol complex, another one on the ice wedge pseudomorphosis of Yarmolyntsi palaeocryogenic stage. It is revealed that loess and palaeosol horizons are very different in their engineering-geological properties. In particular, insignificant subsidence is a characteristic of only individual samples from the upper horizon of the Middle Pleistocene loesses. Palaeosol horizons usually have higher values of density and natural humidity. They have a heavier particle size distribution. According to the analysis of the water extract, the highly soluble salts are practically washed away from the loess-palaeosol series. The significant influence of palaeocryogenesis processes on the formation of engineering-geological properties of rocks is also described. Key words: loess-palaeosol sequence, Pleistocene, engineering-geological characteristic of sediments, palaeocryogenesis.

Grain-size-dependent geochemical characteristics of Middle and Upper Pleistocene loess sequences from the Junggar Basin: Implications for the provenance of Chinese eolian deposits

Thick loess-paleosol sequences are widely distributed in the arid inland basins of northwestern China. The geochemical composition of these sediments provides important constraints on the provenance of Chinese eolian deposits. However, grain-size-dependent geochemical characteristics of Early-Middle Pleistocene loess deposits from these arid inland basins have not been investigated. The paucity of such studies hinders a full understanding of provenance changes of loess deposits from the Chinese Loess Plateau (CLP). In the present study, we performed a detailed major, trace and rare earth element analysis of multiple grain-size fractions of Middle Pleistocene loess deposits from the Dongwan section (DW) in the Junggar Basin. We found that the major, trace and rare earth element concentrations of the DW loess are grain-size-dependent, with higher concentrations in the fine fraction. In addition, the <5 μm and 5–20 μm fractions are more homogeneous in composition than the coarse fractions, indicating that they were extremely well mixed prior to deposition. Compared to contemporaneous loess deposits from the CLP and surface loess samples from Tajikistan and Ili Basin in Xinjiang, the loess deposits of the DW section have higher major element ratios of TiO2/Al2O3 and K2O/Al2O3, and REE ratios of LaN/YbN, GdN/YbN and LaN/SmN, indicating that the loess deposits in the Junggar Basin have distinctive local or regional geochemical characteristics. These results support the view that the Junggar Basin is not a potential source region of the loess in the CLP, at least since the Middle Pleistocene. Furthermore, temporal variations in the major element and REE ratios of the coarse fractions (20–75 μm and >75 μm) from the DW section changed significantly at ~0.5 Ma, which may have arisen from intensified physical erosion or increased wind speeds in the northern Tianshan area.

A new correlation between Chinese loess and deep-sea δ18O records since the middle Pleistocene

The Quaternary Chinese loess is one of the most continuous terrestrial sediments, and preserves excellent palaeoclimate records at different timescales. The conventional land-ocean palaeoclimatic comparison has been established by correlation between magnetic susceptibility of the Chinese loess and deep-sea δ18O records during the 1980s. However, such a correlation results in long-standing debates on the lock-in depth of the palaeomagnetic polarity boundaries in Chinese loess. In this study, the lock-in depth of palaeomagnetic signals for loess <130 ka were estimated through correlation between palaeomagnetic relative palaeointensity (RPI) and 10Be RPI curves, and are linearly related with the calculated loess dust accumulation rate. Palaeomagnetic displacement for the geomagnetic polarity boundaries and excursions in the middle Pleistocene loess at Luochuan, Zhaojiachuan and Lingtai sections could be estimated using the linear relation only in decimeter scale (generally <50 cm) which indicates paleomagnetic boundaries in Chinese loess can be used as reliable age control points after moderate adjustments. Based on this as well as a high-resolution loess magnetostratigraphy and grain-size sequence, we propose a new scheme for palaeoclimatic correlation between Chinese loess and marine sediments since the middle Pleistocene.

Інженерно-геологічна характеристика порід лесово-ґрунтової серії опорного розрізу Підволочиськ (Подільська височина)

Key section Pidvolochysk is located in the quarry of the currently inactive brick factory. It represents the Upper and Middle Pleistocene loess-soil series as well as some fossil paleocryogenic forms of the Khmelnytsky Plateau of the Podolian Upland. The ice-wedge casts of the Final Pleistocene (Krasyliv) palaeocryogenic stage are presented here especially intensely. One of them is studied on the engineering-geological aspect. In particular, it has been defined, that the loess filler of ice-wedge cast, in contradistinction to loesses that contain it, is loose and subsiding. This is of great importance for the engineering-geological evaluation of the properties of loess-soil strata. Key section Pidvolochysk is well stratified. Two Upper Pleistocene loess horizons (MIS 2, 4) and the upper horizon of Middle Pleistocene loesses (MIS 6) are disclosed here. Besides loess horizons, Dubno fossil soil (MIS 3) and Horokhiv fossil soil complex (MIS 5), as well as delluvial-solifluctional stratum above Dubno, are developed here. The engineering-geological properties of the loess and palaeosol horizons, including their subsidence, have been studied in detail. Individual characteristics of distinct stratigraphic horizons are given. It can be used during the engineering-geological research in the areas of distribution of Pleistocene loess-soil series. Key words: loess-soil series, key section, Pleistocene, palaeocryogenesis, engineering-geological features, Podolian Upland.

Clay mineralogical characteristics and the palaeoclimatic significance of a Holocene to Late Middle Pleistocene loess–palaeosol sequence from Chaoyang, China

ABSTRACTChanges in soil chemistry in response to varying climatic regimes can alter the equilibria of soil systems and result in different clay minerals. Variations in phyllosilicate clay composition can reflect temporal and spatial climatic changes, such as summer/winter monsoon cycles. The objective of this research was to investigate the mineralogy of the clay fractions as a proxy for determining variations in the East Asian monsoon climate, based on a section at Chaoyang in China spanning the last 0.423 Ma BP. The clay mineralogy record in the Chaoyang section was compared with other proxies as recorded in this section and with other palaeoclimatic indicators, including oxygen isotopes from oceanic sediments and loess–palaeosol sections on the Chinese Loess Plateau (CLP). The results from clay mineralogy and related climatic studies show that the summer monsoon has a trend of four increased stages and four decreased stages; whereas the winter monsoon displays the opposite trend. During the last 0.423 Ma BP, the strongest winter monsoon occurred around 0.243–0.311 Ma BP. During this period, which included an intense winter monsoon, the soil in the section had the least illite, one of the smallest kaolinite and illite/Chlorite (I/C) indices and an overall decreasing clay content. The period 0.225–0.243 Ma BP had the strongest summer monsoon over the last 0.423 Ma BP. This period had the greatest amount of illite, the highest I/C index, greater overall clay content and the strongest magnetic susceptibility signal. Additionally, this section contained the smallest mean grain size. The multi-monsoon climate cycles of alternating cold-dry and warm-moist conditions as recorded in the Chaoyang section corresponded well with multiple glaciation cycles based on deep sea sediments. This indicates that the Chaoyang section provides a record of palaeoclimate changes in northeast China that can be linked to mineralogical suites to assist in reconstructing the palaeoclimate over the Late Middle Pleistocene, and complements the global palaeoclimate records in the CLP.

Influence of moisture content on shearing strength of unsaturated undisturbed quaternary system middle pleistocene

The unsaturated undisturbed quaternary system middle pleistocene loess, a typical unsaturated soil, often occurs in the implementation of western development strategy. To obtain the shearing strength characteristics of this unsaturated undisturbed loess, based on the analysis of mineral composition, the triaxial shear test of undisturbed quaternary system middle pleistocene loess under different moisture contents is conducted with the specialized triaxial instrument for unsaturated soil. The test results show that the mainly mineral composition of undisturbed quaternary system middle pleistocene loess is quartz and albite. Under the same confining pressure, the matric suction increases with the decrease of moisture content. The smaller the moisture content, the larger the matric suction; the higher the moisture content, the lower the matric suction. Under the same moisture content, the matric suction increases with the confining pressure and reaches a maximum when the confining pressure is 100 kPa, and then decreases with the increase of confining pressure. This phenomenon is closely related to the grain contact tightness of soil mass under high confining pressure. According to the triaxial test of loess, the sample of loess experiences 4 stages from loading to failure: 1) compaction stage; 2) compression stage; 3) microcrack developing stage; 4) shear failure stage. The test sample is of brittle failure (weak softening) under low moisture content and confining pressure. With the decrease of matric suction and the increase of consolidated confining pressure, the stress-strain curve changes from softening type to ideal plastic type. In the shearing strength parameters of unsaturated undisturbed loess, the influence of moisture content on internal friction angle is small, but that on cohesive force is obvious. Therefore, the shearing strength of unsaturated undisturbed loess is higher than that of saturated undisturbed loess and varies with the moisture content.

Deciphering magnetoclimatological patterns of late Early to early Middle Pleistocene loess–paleosol sequences in the western Chinese Loess Plateau

A detailed environmental magnetic investigation in conjunction with geochemical, bulk grain size and redness analyses of late Early to early Middle Pleistocene loess–paleosol sequences at the Jiuzhoutai and Caotan loess sections has been carried out, aimed to explore the reliability of magnetic parameters as paleoclimatic proxies in the western Chinese Loess Plateau (CLP). The results show that magnetic enhancement of early- to mid-Pleistocene loess–paleosol sequences at both sites is not solely due to the neoformation of ultrafine magnetic particles through pedogenesis, but in the case of several loess layers (e.g., L8 and L9) is more attributed to the significant input of coarse-grained magnetic minerals associated with the advance of desert margin and/or with significant changes in local sediment input. Since the magnetoclimatological signals studied here are obviously controlled by both pedogenesis and wind vigor, measurements of magnetic susceptibility (χ) and saturation isothermal remanent magnetization (SIRM), both of which are responsive to both ultrafine pedogenic magnetic particles and eolian coarse-grained pseudo-single domain/multi-domain magnetic particles, could not provide unambiguous interpretation of the magnetic response to the East Asian summer monsoon intensity. In contrast, anhysteretic remanent magnetization (ARM) and the percentage of frequency-dependent magnetic susceptibility (χfd%), which are notably responsive to ultrafine magnetic particles, can aptly trace changes in the concentration of pedogenic magnetic particles and can therefore be used as reliable proxies of pedogenic intensity. The magnetic grain size dependent proxies, e.g., ARM/χ and ARM/Ms (Ms, saturation magnetization), geochemical indices (e.g., chemical index of alteration, Zr/Rb and Al/Si ratios), and bulk grain size records all exhibit concordant variations and are more straightforward proxies for addressing the East Asian monsoon variability. Therefore the combination of multi-parameter mineral magnetic, geochemical and grain size analyses is very useful for distinguishing, delimiting and correlating loess sequences, and for accurately deciphering their paleoclimatic signals embedded in the weakly weathered loess. As the classical precipitation-driven pedogenic model for magnetic susceptibility enhancement is not entirely applicable to the early- to mid-Pleistocene loess developed in the semi-arid western CLP, considerable caution should also be warranted in using magnetic susceptibility measurements alone in the quantitative reconstruction of paleoprecipitation.

Dating Middle Pleistocene loess from Stari Slankamen (Vojvodina, Serbia) — Limitations imposed by the saturation behaviour of an elevated temperature IRSL signal

Recent advances in post-IR IRSL dating have led to breakthroughs in dating upper Middle Pleistocene loess sequences. Here, an elevated temperature post-IR IR protocol using a second IR stimulation temperature of 290°C is applied to eleven polymineral fine-grain (4–11μm) samples from the lower part of the Middle–Lower Pleistocene Stari Slankamen loess–palaeosol sequence with the aim of refining the site's age model and investigating the behaviour of both the IR50 and the pIRIR290 signals in material close to or in luminescence signal saturation. Both signals from the 8 samples below the prominent erosion surface represented by a gravel layer at ~13m were found to be in field saturation (i.e. no systematic increase in burial dose with depth). The average ratio of the sensitivity-corrected natural signal to the laboratory saturation level for the pIRIR290 is 1.00±0.03 (n=8) indicating that field saturation is equal to laboratory saturation for this signal. Minimum equivalent dose estimates were calculated from 2*D0 values, giving minimum age estimates of ~230–390ka; this result suggests an upper limit for dating these loess deposits of ~300ka. The age estimate of the younger sample SSK2 is in good agreement with the quartz OSL age, showing that the pIRIR290 signal is bleachable in nature and can be used to date material as young as ~20ka. Our data suggest that the loess unit V-L2 accumulated during Marine Isotope Stage (MIS) 6 and that the erosional event marked by an unconformity and gravel layer between loess units V-L2 and V-L3 has a minimum age of ~170ka. Pedocomplex V-S1 can be correlated with the complete MIS 5 period. Furthermore we suggest a minimum age of ~250ka for the loess unit V-L3 and palaeosols V-S3, V-S4 and V-S5; considerably older than proposed by many previous studies.

Palaeoenvironment and geoconservation of mammoths from the Nosak loess–palaeosol sequence (Drmno, northeastern Serbia): Initial results and perspectives

A Quaternary site at Drmno (comprising of Middle and Late Pleistocene loess–palaeosol sequences) near Kostolac, northeast Serbia, attracted attention from the general public and scientists, when several steppe mammoth and other mammal skeletons from Middle Pleistocene fluvial deposits were discovered in 2009 and 2012. This paper presents the combination of malacological and enviromagnetic analyses, preliminary luminescence dating, litho-pedostratigraphic and palaeo-relief investigations that were applied to the Nosak loess–palaeosol sequence for the 2012 findings. The results confirm and emphasize the antiquity of the sediments preserved in the Nosak section and demonstrate the significance of the detailed and relatively complete palaeoenvironmental record they contain. These discoveries can significantly contribute to setting the background towards an improved understanding of the evolution of mammoths on the European continent.

Інженерно-геологічна характеристика лесово-ґрунтової серії опорного розрізу Ванжулів (Подільська височина)

In the section Vanzhuliv, the loess-soil series of the northern part of the Podillia Upland is exposed. In this section, the thickness of the Upper Pleistocene loess deposits is still relatively considerable, whereas the thickness of the Middle Pleistocene loess deposits increases. The detailed description of the section and of the engineering-geological properties of all the distinguished horizons and sub-horizons is given. Besides that, the influence of the large-scale fossil permafrost structure on the properties of loess is described, basing on the example of the pseudomorphic structure of the Lanivtsi paleocriogenic stage. Key words: loess, paleosoils, engineering-geological properties, subsidence, paleocriogenesis, Podillia.

Malacological characteristic of the Middle Pleistocene loess (MIS-6) of the Batajnica locality (Serbia)

Malacological characteristic of the Middle Pleistocene loess (MIS-6) of the Batajnica locality (Serbia)

Detection and correlation of widespread cryptotephras in middle Pleistocene loess in NE Japan using cummingtonite geochemistry

We used cummingtonite chemistry to detect strongly weathered widespread cryptotephras within middle Pleistocene loess and fluvial terrace deposits and to correlate them with previously reported tephras in central and NE Japan. We correlated a cummingtonite-bearing cryptotephra widely distributed in NE Japan below the Ichihasama Pumice (108–146ka) and above the Iwadeyama Pumice (IwP, 160–240ka) with the Iizuna-Kamitaru c tephra (Iz-KTc), which erupted from Iizuna volcano, central Japan. Iz-KTc is thus a widespread middle Pleistocene tephra covering both central and NE Japan. Moreover, we detected the Adachi-Medeshima tephra (Ac-Md), which had been previously inferred to be a late Pleistocene tephra (80–100ka), below the Iz-KTc and IwP tephras (125–150ka) and above the Hagimori White Ash tephra (210–250ka). Therefore, Ac-Md must be a middle Pleistocene tephra with an eruptive age older than 125–150ka and younger than 210–250ka. We also detected a cummingtonite-bearing tephra older than 210–250ka and younger than 250–300ka in the Isawa area of NE Japan and correlated it with a previously reported tephra in central Japan. Thus, like Iz-KTc, this tephra is a widespread middle Pleistocene tephra.

Geochemical evidence for the provenance of middle Pleistocene loess deposits in southern China

The provenance of middle Pleistocene loess in the middle and lower reaches of the Yangtze River, the most intensively investigated loess deposits outside the Loess Plateau region in China, remains controversial. Identification of the provenance will provide crucial insight into the environmental implications of this valuable sedimentary archive, and into the potential role of the East Asian winter monsoon in transporting the dust from deserts in the Asian interior. In this study, geochemistry was used to compare the provenance of loess in the lower reaches of the Yangtze River in southern China with that inferred for loess deposits on the Loess Plateau in northern China. Compared with samples from the Loess Plateau, the <20 μm fraction in the loess deposits of southern China has higher TiO 2/Al 2O 3, Zr/Nb, Zr/Al, Zr/Ti, Zr/Hf, Y/Al and La N/Sm N ratios, and lower Eu/Eu*, Th/Nb, Y/Nb and Al/Nb ratios. The clear distinction in immobile element ratios between samples from the two regions indicates that the loess deposits in the two regions have different provenances. The inferred difference in source area is also supported by variations in the major element composition of bulk samples obtained in this study and collected from published data. These lines of evidence indicate that the deserts in the Asian interior are not the primary provenance for the southern loess. It is suggested that the adjacent floodplains to the north of Yangtze River are the dominant dust sources, and the occurrence of sustained loess deposits in the lower reaches of the Yangtze River, currently an area of northern subtropical climate, is an indication of local aridification and strengthened winter monsoon activity during glacial periods as a regional response to the Middle Pleistocene climate transition around 0.8 Ma. The role of the East Asian winter monsoon in transporting the dust from northern deserts to southern China has been overestimated in previous studies.