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This paper presents an overview of the results obtained by collaborative use of integrative multidisciplinary investigation of a highly unique geological section discovered in the south-eastern part of the Gulf of Finland. The main aim of this study is to identify the Late Pleistocene palaeoenvironmental and palaeoclimatic changes in the study area during one of the most controversial periods in the Late Pleistocene history, which is the MIS 5. Our approach to achieving the goal is based on the investigation of feldspar-based infrared optically stimulated luminescence (IR-OSL) dated records of pollen-induced palaeoclimate and palaeoenvironmental proxies. Palynological analysis and IR-OSL dates of 29 samples for the first time produced a detailed, characterised and dated sequence of palynological zones M6 to M8 ranging from ca. 94 ka to ca. 70 ka and made it possible to determine the chronological sequence of climate changes in this interval. Representative pollen spectra from 69 samples provided convincing evidence of a warm interval of interglacial rank at least during the latter half of MIS 5. The data obtained in the present study from well-preserved deposits of the second half of MIS 5 provided a novel insight into the palaenvironmental conditions during this period. These results seem to contradict the widely held view according to which the last interglacial stage with the climate conditions similar or warmer than today corresponds to only a small part of marine isotope stage (MIS) 5 of the deep-sea stratigraphy, i.e. MISs 5e lasting ca. 11 ka, and the period from 100 ka to 80 ka is attributed to an Early Weichselian glaciation, which in Northern Eurasia reached its maximum at about 90 ka. However, the findings obtained during the present study are also convincingly confirmed by those of our previous long-term investigations of warm climate-related shell-bearing deposits of various origins from Northern Eurasia including climatically highly sensitive Eurasian Arctic palaeo-shelf area. These results indicated that the overwhelming majority of the warm climate-related dates (ca. 82%) is also concentrated in the latter half of MIS 5 in the time range between 110 ka and 70 ka.

The Lithuanian onshore section of the south-eastern Baltic Sea region, or the so-called Lithuanian Maritime Region (LMR) – a belt several tens of kilometres wide along the Baltic Sea coast – is characterised by a complicated Quaternary structure and many of unsolved problems related to stratigraphy and palaeogeography. The inter-till lacustrine sediments widespread in the middle part of the Pleistocene thickness play a key role in solving the mentioned problems. The primary inter-till sediments were attributed, as a single lithostratigraphic unit, to the late Saalian Glaciation (MIS 6, Pamarys Sub-Formation; according to the Lithuanian Quaternary Stratigraphic Scheme). Subsequent detailed investigations show that the investigated inter-till succession represents a more complicated sediment complex formed over a wide time interval from the Saalian ice sheet decay at the very end of MIS 6 to the beginning of severe climate cooling during MIS 4. This standpoint is confirmed by the results of a few series of OSL and IR-OSL datings of inter-till sediments, as well as by data of pollen and diatom analysis. The more detailed stratigraphic subdivision of the inter-till sedimentary complex offers a new significant insight into the regional stratigraphic scheme of the Quaternary. As a result of the mentioned investigations, a new original reconstruction of the palaeogeographic situation in the LMR during the MIS 6 – MIS 3 time span was carried out. The lowermost part of the investigated inter-till sediments, attributed to MIS 6, could be correlated with the third MIS 6 warming in Northern Eurasia about 155 ka ago. The reconstruction of the palaeoenvironmental changes starting from MIS 6 and lasting to MIS 3 shows that the Eemian Sea MIS 5e in age was absent in the LMR, while part of the south-eastern Baltic Sea region was covered by a continental ice sheet during MIS 4 and, possibly, the very beginning of MIS 3.

Long-term investigations devoted mostly to the Eurasian Arctic sedimentary deposits have provided dated climatic sequence within the Late Pleistocene period. Most of the dates (ca. 315) were obtained by electron spin resonance (ESR) method on marine mollusc remains taken directly from transgressive marine sedimentary deposits. Here, it is shown that the climatic signature revealed in the studied sedimentary sequences can be compared by proxy- and chronologic correlation with the climatic signals recorded in different parts of the continent from deposits of marine, freshwater, and terrestrial origin. The resulting climate-chronostratigraphic record allow the last interglacial to be placed approximately between 145–140 ka and 70 ka with concentration of overwhelming majority of the warm climate-related dates (ca. 82%) in the second half of Marine Isotope Stage (MIS) 5 in the time range between 110 and 70 ka. This evidence coincides with integrative multidisciplinary results derived from the south-eastern coast of the Gulf of Finland. They show unambiguously that the second half of the MIS 5 sequence, at least between ca. 94 ka and 71 ka, reflects the fully interglacial character of the studied deposits. The climate-chronostratigraphic record within MIS 3 displays a sequence of three successive palaeoenvironmental events (59.0–52.0 ka, 47.5–40.0 ka and 32.4–24.8 ka), which are interpreted as the consequence of large-scale climate amelioration during which marine sedimentation occurred on palaeo-shelves what is now dry land. The consistency of the parallel comparative dating results obtained in this study by different methods, both the numerical and relative, exemplify the potential of palaeodosimetric dating methods mainly used in this study — mollusc shell-based electron spin resonance (ESR) and feldspar-based infrared optically stimulated luminescence (IR-OSL) — to chronologically organize the sequence of the Late Pleistocene palaeoenvironmental events, and to improve understanding of the palaeoenvironmental evolution during this period.

This paper discusses successive changes in the evolution of the fluvial system observed throughout the Blądzikowo Formation at the Mrzezino key site in northern Poland. The study focuses on the development of fluvial sedimentation during Marine Isotope Stage 7. The sedimentary record of the Pleistocene at the study site shows a well-developed sequence that is over 30 m thick. The Blądzikowo Formation shows a quick evolution of the fluvial system from a high-energy sandy braided river, to a meandering sandy river and, finally, to a low-energy meandering/anastomosing river with significant suspension settling. This transition is explained as a decrease in flow energy, increase in aggradation ratio and expansion of accommodation space during deposition time. A change in the fluvial system has not been manifested in the variations of the plant cover. Palynological analysis indicates that climate conditions were generally stable, cool and humid (boreal). Sediment transport occurred towards the N-NW, through a valley with a NW-SE axis. Infrared optically stimulated luminescence (IR-OSL) dating shows the sequence formed from 225.6 ± 17.2 to 210.5 ± 16.6 ka. Well preserved fluvial cycles and 35 m of thickness suggest the intensive accumulation of the Blądzikowo Formation with decreasing ratio of lateral erosion. It suggests an increasing influence of base level rise on evolution of fluvial system, mostly during MIS 7.

The object of the study was the fluvio-aeolian sedimentary succession in eight sites located in the central part of the European Sand Belt, in Poland and NW Ukraine. Based on the lithofacies, pedological and morphoscopic analyses, the analyses of frost structures and grain size as well as the TL, IR-OSL and 14 C dating, three lithofacies complexes deposited at the turn of the Weichselian and Holocene were documented. The fluvial complex was deposited in the Pleniglacial within a sandbed braided river, which in the final stage of deposition of the complex was transformed into an anastomosing river. These rivers functioned in continuous permafrost coverage. The fluvio-aeolian complex was the result of aeolian deposition and fluvial redeposition, resulting from the degradation of continuous permafrost at the turn of the Pleni- and Late Glacial. These processes operated in the areas abandoned by regular flow. The aeolian complex was accumulated following the development of aeolian sand forms – sandy and silt covers as well as parabolic and longitudinal dunes, after the complete degradation of permafrost at the end of the Late Glacial and Holocene. Improving climatic conditions were expressed by the presence of fossil levels of initial gley soil in the roof of the fluvio-aeolian complex as well as poorly developed podzolic and colluvial soils in the aeolian complex.

The Netiesos section in southern Lithuania exposes a late Pleistocene sedimentary sequence at a depth of between 17 and 4 m. An interdisciplinary study of the section investigated the environmental changes that occurred in the study area during the greater part of Marine Isotope Stage (MIS) 5. Geochemical, thermoluminescence, palaeontological (plant macro-remain, diatoms, fishbones) and magnetic susceptibility analyses were performed on numerous sediment samples. Chronological control of the sequence was provided by electron spin resonance (ESR), infrared optically stimulated luminescence (IR-OSL) and conventional radiocarbon dating methods. This interdisciplinary approach enabled the subdivision of the section into stratigraphic units reflecting environmental changes. According to chronological data, the development of the Netiesos palaeolake began at the end of the Medininkai (Saalian) glaciation, which is thought to correlate with MIS 6, and continued up to the thermophilous deciduous forests phase of the subsequent last interglacial of MIS 5. Sediments of the final phase of the interglacial are missing, as are the initial and final phases of the following early Nemunas (Weichselian) cooling (MIS 4). The palaeomagnetic Blake Event was recorded in the interglacial sediments. One of the richest palaeofloras in the East Baltic region was observed representing the second half of MIS 5. The implications of the results for the regional late Pleistocene climato-chronostratigraphy are discussed.

1. IntroductionWe welcome Erdem Bekaroglu’s (E.B.) comments on our paper(Dogan et al., 2012) and the opportunity to discuss some importantaspects related to MIS 5a and MIS 3 high sea-level events notreflected in the paper. We have endeavoured to follow thecomments in the order of their presentation.2. Previous resultsWe are of the opinion that it can be a rather thankless task tosynthesize diverse and often contradictory data from all the avail-able sources. Therefore, where possible, we prefer to rely on ourown data obtained during the last three decades over the vast areaof Northern Eurasia (see, e.g., Molodkov and Bolikhovskaya, 2010,and references therein).As to Heinrich event (HE) 5, we would like to indicate that thecoral-based UeTh ageof this event (54.2e49.4 ka) maybe the rightone, in the case that three conclusions made by Lambeck et al.(2002, pp. 202e203) are accepted. Otherwise

The time span of the past 200 ka has been marked by many large-scale global and regional climate changes, between warmer and cooler conditions. As is usually the case when studying the past, palaeoenvironmental data become scarcer with increasing age. Therefore, every detailed palaeoenvironmental record may be of special interest to Quaternary geologists in terms of palaeoenvironmental reconstructions, correlations and general stratigraphy of the Quaternary. In this paper we present a long palynological record of terrestrial flora and an ESR-dated marine record of global-scale climatic variation obtained from a loess–palaeosol sequence in the East European Plain and continental margin of Northern Eurasia for the time span starting from the penultimate glacial period correlating with Marine Isotope Stage (MIS) 6. These records show that in combination they have a potential of assigning warm/cold climate related deposits to the chronostratigraphically organised sequence of the late Pleistocene palaeoenvironmental events.

Original materials of pollen analysis and ESR-chronostratigraphic studies provided a basis for reconstruction, chronological subdivision and inter-regional correlation of palaeoclimatic events and sediments of palaeo-shelf, glacial–periglacial and extra-glacial regions of Northern Eurasia within the scope of the Brunhes Epoch. Chronostratigraphic position of the identified palaeoenvironmental events and corresponding horizons in the composite chronostratigraphic column is established on the base of ESR-analyses of subfossil mollusc shells collected from marine, freshwater and terrestrial deposits. The palyno-chronostratigraphic record displays a sequence of 8 intervals (the Holocene included) of warm climate and high sea-level stands, when marine sedimentation occurred on palaeo-shelves, and 7 glacial epochs. The alternating intervals are either fully recorded as complete glacial-interglacial rhythms, or represented by a large enough number of consecutive climatic-phytocoenotic phases. The rhythmic regularity in the sequence of glacial and interglacial events has been inferred from detailed palynological data on reference sections of loess–palaeosol series in the centre of the East European Plain (Arapovichi, Otkaznoe, Likhvin, Strelitsa sections). A clear agreement between long pollen record, directly dated warm-climate-related deposits and other records of palaeoenvironmental evolution known from literature has been established for the upper 15 oxygen isotope stages (OIS 15 to 1). Finally, we come to a conclusion that the integrated climate-chronological sequence may be taken as a basis for inter-regional correlations of palaeo-shelf and terrestrial sediments within Northern Eurasia; it may be used as an intermediate link in the continent–ocean correlations.

In this paper the results of pollen analyses of the loess–palaeosol sequences (LPS) of the East European Plain are presented. Environment and vegetation evolution during the time of loess and soil formation has been characterized by pollen data of the reference sections of the Upper Oka (Likhvin–Chekalin section), the Upper Don (Strelitsa section), the Middle Kuma (Otkaznoe section), the Middle Dniester (Molodova and Ketrosy sections), and the Middle Desna (Arapovichi section) regions. Palaeomagnetic studies indicate that the sediment sequence studied spans at least the last 800 ka. The palynological climate proxies show a pattern of periodic variations comprising nine interglacial and eight glacial stages. On the basis of palynological results coupled with the electron spin resonance (ESR)-chronostratigraphic data on mollusc shell-bearing marine and terrestrial deposits, the reconstruction, periodization and distant correlation of palaeoclimatic events and deposits of glacial, periglacial and extraglacial zones of Northern Eurasia over the last 600,000 years have been carried out. Based on palaeoenvironmental evidence, it has been established that the full-interglacial conditions revealed are centred at about 580, 400, 310, 220 and between 145 and 70 ka. A broad correspondence between the long palynological sequence, directly ESR-dated warm-climate-related events and other palaeoenvironmental records described in the literature is noted at least for the 11 upper marine isotope stages (MIS 11–1).