The tallest aeolian landform in Europe (similar to 170 m above the base), the Sarykum dune complex, is located in the southwestern Caspian Depression near the Caucasus Mountains. Its morphology and evolution remain poorly studied. In this study we investigate the dune complex through a synthesis of geomorphological, geological, and geochronological methods. Our findings link its development to major regression phases of the Caspian Sea driven by climatic aridifications during the Late Pleistocene-Holocene. Optical stimulated luminescence dating indicates that dune formation began at least 60 ka during the Atelian regression, with reactivation around 11-6 ka during the Mangyshlakian regression. By the mid-Holocene, the complex had nearly reached its modern height. The Shura-Ozen' River, which divides the dune complex in two major segments, played a significant role in the complex's evolution, influencing aeolian sediment transport and trapping material on its banks, particularly on the left bank, where the highest Central Massif is located. Extensive vegetation now stabilizes most of the complex, except for active ridges in the Central Massif. A numerical analysis of wind potential for dune migration, based on recent meteorological data, shows that sand movement is primarily driven by self-sustaining NW-SE wind fluctuations. Paleowind analysis suggests that similar long-term wind patterns have persisted since the onset of aeolian deposition during the Atelian phase. Our study sheds new light on the Sarykum dune complex's history and highlights its significance as a dynamic archive of climatic and geomorphic processes in the Caspian region.

The find of an incomplete skeleton of the mammoth Mammuthus cf. intermedius near the Lenino village (Yenotayevka district, Astrakhan region) is described. The bones occurred in the layer of continental sandy deposits of the Singil regression (end of the Middle Neopleistocene). The skeletal remains belong to a female with an individual age of 35—40 years. This find allows us to clarify the species diversity of elephants that inhabited the Lower Volga area during the relatively cool phase of the Khazar faunal complex existence. Some bones bear what appears to be traces of ancient human activity including traces of hunting. Traceological analysis of one of the bones makes it possible to suggest the anthropogenic nature and ancient origin of these traces. The available evidence may be taken as an indication that the first humans appeared in the territory of modern Astrakhan Region at least at the end of the Middle or beginning of the Late Neopleistocene (MIS 6 — MIS 5). Previously, it was thaught that humans appeared in this territory only 12—14 thousand years ago.

The malacological characteristic of the Middle and Upper Neopleistocene deposits of the Vetlyanka locality (Lower Volga Region) is given in the paper. On the base of lithological and textural features of the sediments, as well as mollusc complexes the palaeoenvironment changed from fluvial (Early Khazar, Singil beds), lacustrine-lagoon (Late Khazar), to marine (Early Khvalyn) conditions. Охарактеризованы комплексы моллюсков из отложений среднего и верхнего неоплейстоцена местонахождения Ветлянка (Нижнее Поволжье). На основе литологических особенностей осадков и комплексов моллюсков по разрезу прослежено изменение палеоэкологических условий от аллювиальных (ранний хазар, сингиль), озёрно-лагунных (поздний хазар) к морским (ранняя хвалынь).

During the Quaternary, the Lower Volga region was typically a shallow shelf of the Caspian Sea. This region regularly and distinctively responded to sea level fluctuations by changing both sediments and biota. This region is therefore a key to understanding the history of the transgressive-regressive cycles of the Caspian Sea during the Quaternary. There is a wealth of information about the Quaternary deposits of the Lower Volga region; however, their diversity of facies, erosional processes, and fragmented sections create difficulties in stratigraphic interpretation and the development of paleogeographic models. The studied 500-m section of borehole 8 Ulan-Khol is among the few in the Caspian region that allows for the sequential reconstruction of the Quaternary history of the region in one section. These borehole data offer a unique opportunity to reconstruct transgressive-regressive cycles in Pleistocene basins located in the most southeastern part of Europe (the Caspian region). Based on biostratigraphic, sedimentological, and paleomagnetic methods, we were able to define main Early, Middle, and Late Pleistocene units, which were correlated with regional stratigraphical units. Each unit corresponds to regional paleogeographic events and sedimentation modes characterized either by basinal (brackish water) or continental conditions when lagoons and fluvial landscapes dominated. The borehole interpretation integrated with regional data demonstrates a complex history of Caspian basin development during Apsheronian time (MIS 63–20) with the presence of a strong regression in its final stage, accompanied by a previously unknown advance of the Paleo-Volga valley to the latitude of Astrakhan city and further south. This regression and the formation of the Paleo-Volga valley continued during Tyurkyanian time (MIS 19). By the end of the Tyurkyanian, the regression was followed by a transgressive stage, which culminated in Bakunian time (MIS 18–12). The Khazarian stage (MIS 11–5) of Caspian Sea development was characterized by a constant change from alluvial-marine to marine and estuarine environments. The borehole data support our earlier conclusion that the Singilian deposits separate the lower (MIS 11–7) and upper (MIS 5) Khazarian units. New data support the existence of only one transgression of the Caspian Sea during Khvalynian time (MIS 3–2); after its maximum stage the sea level gradually decreased with the formation of coastlines at several terrace levels. Due to its high deposit thickness and rich paleontological, stratigraphic and lithological information, Ulan-Khol borehole 8 can be considered a key site for the Northern Caspian area.

Охарактеризованы комплексы моллюсков из отложений среднего и верхнего неоплейстоцена местонахождения Восток (Нижнее Поволжье). На основе литологических особенностей осадков и комплексов моллюсков по разрезу прослежено изменение палеоэкологических условий от озерно-лагунных (ранний хазар, сингиль), морских (поздний хазар), аллювиальных (поздний хазар) к морским (ранняя хвалынь). The malacological characteristic of the Middle and Upper Neopleistocene deposits of the Vostok locality (Lower Volga Region) is given in the paper. On the base of lithological and textural features of the sediments, as well as mollusc complexes, it is shown that the palaeoenvironment changed from lacustrine-lagoon (Early Khazar, Singil), marine (Late Khazar), fluvial (Late Khazar) to marine (Early Khvalyn) conditions.

В статье обсуждается гипотеза связи Понто-Каспийского бассейна с Баренцевым морем в плейстоцене через центральную часть Русской равнины по долинам палео-Дона и палео-Волги. На основе полевых данных и палеонтологических заключений делается вывод о ее несостоятельности.

There are many Middle-Upper Pleistocene outcrop sections in the Lower Volga region (Caspian Lowland, Russia) in between cities of Volgograd and Astrakhan. The present study focuses on the Seroglazovka locality, which is among the most famous key sites within the Lower Volga region. The Seroglazovka locality is of great regional interest, because of its clear exposure of genetically variable Middle and Upper Pleistocene deposits containing diverse complexes of fauna and flora. Even though the Seroglazovka locality was studied by many researchers, the diversity and along-strike variability of the depositional facies often makes the stratigraphic interpretation challenging. In this study, we performed an extensive and integrated study of the Seroglazovka locality including detailed outcrop mapping with lithological description, as well as diverse biostratigraphy analysis and OSLdating. In addition to outcrop data, we used recently obtained borehole data near the Seroglazovka locality, which cover almost the entire Quaternary interval. This multidisciplinary approach permitted us to confidently stratify the Quaternary interval of the Seroglazovka locality into a series of regional horizons and subhorizons including the Akchagyl, Apsheron, Tyurkyan, Baku, Khazar and Khvalyn. Furthermore, we correlated the interpreted section to the adjacent parts of the Caspian Lowland and the Regional Stratigraphic Scale. Our results allowed us to determine the main Pleistocene palaeoenvironments and their evolution within the study area. Our findings are important to understand the processes, which led to the modern faunistic composition of the Lower Volga region, and to clarify the role of glacial refugia in the settlement of certain species and further colonization of water basins and land areas with habitable environments. Finally, we suggest the Seroglazovka locality as the key reference Pleistocene section for the Lower Volga region.

The Vastyanskiy Kon’ (VK) outcrop is the largest exposure of Quaternary sediments in the northeastern European part of the Russian Federation. The VK consists of Eemian to Weichselian marine and continental sediments that were deformed within a glaciotectonic complex of terminal moraine of the advancing Late Weichselian Kara Sea Ice Sheet. However, a few aspects of the stratigraphy and dynamic evolution of the VK glaciotectonic complex remain unresolved and ambiguous. A particular debate concerns the structural position and age of the so-called “lower diamicton” (LD), a till-like unit, which generally occurs within the central part of the VK section. Two models on the development of the LD unit have been previously proposed. According to the first model, the LD is situated in its original stratigraphic position and reflects possible earlier Early/Middle Weichselian glaciation and is later deformed by Late Weichselian proglacial glaciotectonism. The second model suggests that the LD unit is a result of an injection of the overlying Late Weichselian lodgement till into underlying sandy units. In our study, we performed a detailed tracing of stratigraphic units and structures utilizing classic surface mapping and 3D photogrammetric methods to access previously understudied parts of the VK. Our observations show that the architecture of the VK glaciotectonic complex represents an imbricate fan and partly support the model where the LD likely represents a till flow unit sourced from the overlying lodgement till under subglacial deformation mode. Finally, we conclude there is no evidence for postulated Early/Middle Weichselian glaciation in the study area.

Комплексно изучен разрез олигоценовых (майкопских) и подстилающих эоценовых отложений скважины 768 глубиной 362 м, который может служить опорным как для Северных Ергеней, так и для всей северной части Восточного Паратетиса. Данные по литологии, моллюскам и бентосным фораминиферам дали возможность расчленить олигоценовую часть майкопской серии на свиты и подсвиты: цимлянскую, соленовскую и калмыцкую, сопоставить их с соседними и удаленными частями Паратетиса, с региоярусной шкалой, восстановить основные условия осадконакопления. По наннопланктону и диноцистам эти подразделения сопоставлены с зональной международной шкалой (Gradstein et al., 2012), а по спорово-пыльцевым данным восстановлена эволюция климата северной окраины Паратетиса. Фитопланктонные, фораминиферовые и палеомагнитные данные показывают сильную редукцию разреза в эоценовой части, где выделены только отрицательно намагниченные фрагменты керестинской, кумской и белоглинской свит, разделенные поверхностями несогласий, и полный набор биотических и палеомагнитных зон нижнего олигоцена. Редкой полнотой отличается нижняя подсвита соленовской свиты (50 м), размытая в большинстве разрезов Предкавказья. Калмыцкая свита в этом разрезе, вероятно, неполная и отвечает лишь первой половине хатта.

The section of well 768, depth 362 m, which opened the Eocene and Maikopian deposits is comprehensively studied and can serve as a reference one for both the Northern Ergeny and the entire northern part of Paratethys. The data on lithology, mollusks, and benthic foraminifera made it possible to break up the Oligocene part of the Maikop Group into formations and subformations: Tsimlyansk, Solenovian and Kalmyk parts, compare them with neighboring and distant parts of Parathethys, with a regostage scale, restore basic sedimentation conditions. Based on nannoplankton and dinocyst composition, these units were compared with the global zonal scale (Gradstein et al., 2012), and according to the spore-pollen data, the evolution of the climate of the Parathethys northern margin was restored. The phytoplankton, foraminiferal and paleomagnetic data show a strong reduction of the section in the Eocene part, where only negatively magnetized fragments of the Keresta, Kuma and Belaya Glina formations separated by unconformity surfaces were distinguished. In the lower Oligocene part we saw the full set of biotic and paleomagnetic zones. The lower part of the Solenovian formation (50 m) is rarely complete, unlike most of the Ciscaucasian sections. The Kalmyk formation in this section is probably incomplete and responds only to the first half of the Chattian.

— This work presents the results of the integrated study of the sequence of Oligocene (Maikop) and underlying Eocene deposits uncovered in borehole 768 (362 m). This section can be regarded as the reference one as for Northern Ergeni, as for the entire northern part of the Eastern Paratethys. The data obtained on lithology, mollusks, and benthic foraminifers enabled us to subdivide the Oligocene interval of the Maikop Group into formations and subformations (Tsimlyanian, Solenovian, and Kalmyk), to correlate it with adjacent and remote areas of the Paratethys and with the scale of regional stages, and to reconstruct the main sedimentation conditions. On the basis of nannoplankton and dinocysts, these subdivisions are correlated with the zonal stratigraphic scale (Gradstein et al., 2012), and according to the palynological data, the evolution of climatic conditions at the Paratethys northern margin is reconstructed. The phytoplankton, foraminiferal, and paleomagnetic data show a significant reduction of the section in its Eocene interval. The latter includes only negatively magnetized intervals of the Keresta, Kuma, and Belaya Glina formations, separated by discontinuities, as well as the complete set of biotic and paleomagnetic zones of the Lower Oligocene. The lower subformation of the Solenovian Formation (50 m), eroded in most of the sections of Ciscaucasia, is characterized by unusual completeness. It is probable that the Kalmyk Formation in this section is incomplete and is represented only by the first half of the Chattian.

ВведениеИсследуемая территория находится на юговостоке Восточно-Европейской равнины в юго-западной части Прикаспийской низменности и представляет собой морскую аккумулятивную равнину, полого наклоненную в сторону Каспийского моря.Стратиграфические и биостратиграфические исследования четвертичных отложений в регионе проводятся на протяжении более чем столетия, их основы были заложены Н.И.Андрусовым на рубеже XIX и XX веков.Сведения о глубинном строении рассматриваемой территории стали появляться с 30-х годов XX века, что было связано с началом поисково-разведочного бурения на нефть и газ и геологического картирования.Несмотря на многочисленность скважин, пробуренных в регионе, важна информация по каждой из них, т. к. позволяет уточнить стратификацию отложений и палеогеографическое развитие территории в четвертичное время.В период 2013-2017 гг.нами был изучен материал из ряда скважин, пробуренных ВСЕГЕИ и Приволжской гидрогеологической экспедицией (г.Астрахань) [Данукалова и др., 2017].Результаты исследований одной из них приводим в этой публикации. Методы исследованияСкважина 3Э расположена на территории Астраханской области (Енотаевский район, лист L-38-XII), в 7.8 км к запад-северо-западу от совхоза Енотаевский, в 21.2 км к северо-востоку от пос.Харба, координаты N 47° 05' 36.750",E 46° 52' 50.370" (рис.1).Скважина была пробурена ПГГЭ в 2001 г. как опорная [Кордонский, Титова, 2002ф].Абсолютная отметка устья -9.5 м.Глубина скважины 455.0 м.Стратиграфическая разбивка отложений, УДК 551.793+564+561(470.46/.47)ПАЛЕОНТОЛОГИЧЕСКАЯ ХАРАКТЕРИСТИКА ПЛЕЙСТОЦЕНОВЫХ ОТЛОЖЕНИЙ СКВАЖИНЫ 3Э (НИЖНЕЕ ПОВОЛЖЬЕ)

The paper is devoted to summary and analysis of the Quaternary stratigraphic investigations and state of the stratigraphic schemes of the different regions of the European part of Russia. The previous summary on the Quaternary of Russia was done in 1984. Thus, this paper presents a brief analysis of the state of the Quaternary investigations in European Russia for the first time since last 30 years. Paper describes history of the Quaternary investigations of the European Russia as well as zoning (structural-facies zones) of the territory in correlation with the conditions of the Quaternary sedimentation. Summary of the Quaternary deposits developed in each zone and validity of stratigraphic units as well as state of the Regional Quaternary schemes is given for each structural-facies zone. Regional schemes are correlated with units of the General Stratgraphic chart of Russia and with International Chart. Analysis of the stratigraphic knowledge on the Quaternary deposits in various structural-facies zones in the European part of Russia has enabled to formulate the unresolved and discussable points and direction for the future investigations of the Quaternary studies. 1. Due to the change of boundary between the Neogene and Quaternary systems and involvement of the Palaeopleistocene stage in the Quaternary, stratigraphic horizons in this interval require additional study, and the most representative sequences should be selected as unit stratotypes for different zones. 2. In the areas of ice cover, various opinions on the age and number of glacial horizons in the Upper-Middle Neopleistocene, their distribution boundaries are still debatable. 3. In some areas and regions (Fore-Caucasus, Caucasus, Urals, Black Sea), differentiation of continental deposits is poorly substantiated by fauna. Their stratification is based on palaeoclimatic reconstructions, geomorphological analysis, and comparison with substantiated by fauna marine sequences of Ponto-Caspian Sea or continental sequences in the Fore-Urals and Western Siberia. Here, the most urgent task is to search for and study sequences in the transitional zone incorporating continental, ingressive, and marine sediments. 4. Development of regional charts for the Quaternary is relevant for the Caucasus, the Black Sea coast regions. (C) 2017 Elsevier Ltd and INQUA. All rights reserved.

— This work presents the history of study of the Neopleistocene Singil deposits, results of analysis the drilling data, and different points of view on the stratigraphy of reference sections of the Lower Volga Region. A large volume of drilling core data indicate that the Singil deposits lie between the Lower Khazar and Upper Khazar deposits, which contradicts a traditional point of view that they lie under the Khazar deposits. As an analysis of faunistical data shows a high level of similarity between the Singil and Khazar assemblages of mammals, it is proposed to consider the Singil mammal assemblage as an analog of the Khazar faunistical assemblage, probably its early phase. The main conclusion of our research is that the accumulation of the Singil deposits occurred at the terminal regressive stage of the Early Khazar basin.

The Kosika locality is situated on the lowest terrace of the Enotayevka River (right channel of the Volga River) near Kosika village, in the Astrakhan region of the Russian Federation. This locality includes several sections, named Kosika 1-4 and Borehole 2 Kosika that are described in detail for the first time. Drilling, sediment descriptions, and sampling were performed during the 2008-2015 field seasons. Application of complex biostratigraphical methods and optically stimulated luminescence (OSL) dates were used to reconstruct the Neopleistocene (Middle-Late Pleistocene) palaeoenvironment in the Lower Volga area. During the Tyurkyan Period (at the early beginning of the Neopleistocene), regression of the Apsheronian Sea began. Lithological features and the presence of freshwater molluscs demonstrate that deposits accumulated in rivers and lakes under humid climatic conditions. Molluscs, ostracods, and dinoflagellates inhabited the Baku Sea. Climate was arid at the beginning of this period and humid during a later phase. Several changes affecting the marine and fluvial environments characterise the Early Khazar period. In particular, the climate oscillated from humid conditions at the beginning to an arid state, then returned to a more humid setting at the end of this period. These changes are indicated by palynological and malacological data. Regression of the Early Khazar Sea occurred during Singil time, when rivers, lakes, and limans (lagoons) existed. Large mammals inhabited plains that were covered by extensive vegetation. The climate during this period was humid and slightly cooler than the present day climate. Late Khazar and Khvalyn transgressions occurred during the Late Neopleistocene. When the Late Khazar Sea retreated from the territory, river valleys became the dominant landscape feature. Floodplains of Late Khazar rivers became sites of deposition of loamy and sandy material emplaced during flood events. At the end of this regressive period, the climate was arid and dry enough to allow for accumulation of anhydrite sediment in shallow lagoons and lakes. Afterwards, the Khvalyn transgression began, as indicated by the occurrence of specific key mollusc species. Fluvial-marine deposits formed geological bodies representative of an undersea delta, which in relief form the Baer Knolls. The modern Volga valley was formed during the Holocene.

Статья посвящена комплексному изучению разреза верхнего мела (турон–нижний маастрихт), вскрытого двумя скважинами на юге Волгоградского Правобережья, на территории Гремячинского месторождения калийных солей. В скважинах изучены комплексы бентосных фораминифер, радиолярий и диноцист. По литологическим и биостратиграфическим данным охарактеризован ряд литолого-фациальных и биотических перестроек. Уточнен возраст захаровской серии, можжевелоовражной, мезинолапшиновской, пудовкинской, зарянской, налитовской и береславской свит по бентосным фораминиферам, радиоляриям и диноцистам. Показано распределение по разрезу вышеназванных групп микробиоты. По бентосным фораминиферам установлены зоны детализированной шкалы верхнего мела Восточно-Европейской провинции, а также местные (фациальные) комплексы. По радиоляриям и диноцистам выделены подразделения в ранге слоев. Проведена корреляция установленных биостратонов по фораминиферам, радиоляриям и диноцистам между собой и с соответствующими биостратиграфическими единицами соседних и отдаленных регионов разных палеобиогеографических областей и провинций. Биостратиграфическая схема верхнего мела дополнена впервые выделенными биостратонами по диноцистам и радиоляриям Восточно-Европейской платформы. Обоснована необходимость перейти от существующего в нашей стране двухчленного деления кампанского яруса к трехчленному. Обсуждена проблема нижней границы маастрихтского яруса и показано, что традиционный вариант этой границы на Восточно-Европейской платформе близок к положению этой границы, принятой в Международной стратиграфической шкале. Приведены некоторые рассуждения о динамике развития среды и биоты в позднемеловую эпоху в Волгоградском Поволжье.

This work discusses the complex characteristic of the Upper Cretaceous (Turonian-Lower Maastrichtian) section recovered by two boreholes in the southern part of the Volgograd region (right side of the Volga River) in the Gremyach’e potash deposit. Lithological and paleontological data (benthic foraminifers, radiolarians, and dinocysts) suggest several lithological-facies and biotic reorganizations. The analysis of the distribution of these microfossils through the section allowed the ages of the Zakharovo Group, Mozhzhevelovyi Ovrag, Mezino-Lapshinovka, Pudovkino, Zarya, Nalitovo, and Bereslavka Formations to be specified. Benthic foraminifers characterize zones of the Upper Cretaceous high-resolution scale available for the East European Platform and local (facies) units, while radiolarians and dinocysts reveal stratigraphic units in a bed rank. Using complex paleontological characteristics (benthic foraminifers, radiolarians, dinocysts), the defined biostratigraphic units are correlated between each other and with their counterparts in neighboring and remote regions of different paleobiogeographic regions and provinces. The Upper Cretaceous biostratigraphic scale is supplemented by the first defined dinocyst and radiolarian biostratigraphic units of the East European Platform. The new data provides evidence in favor of a three-substage division of the Campanian Stage instead the two-substage system presently accepted in Russia. It is shown that the traditional position of the lower boundary of the Maastrichtian Stage in the East European Platform is close to that of this boundary in the Standard Stratigraphic Scale. Some aspects of environmental and biotic evolution in the Volgograd region through the Late Cretaceous Epoch are considered.