Evaluation of water resources changes of the Mountain Dniester in 20th century following the RCP8.5 scenario and based on the “climate-runoff” model

The relevance of the research consists in the need for evaluating the water resources changes of the Dniester due to global warming. The mountain part of the Dniester Basin is a zone of the river's runoff formation that determines its water content. The subject of research includes a process of climate changes and their impact on the water resources of the Mountain Dniester’s catchments. The research focuses on determining the water resources changes under current and possible future climatic conditions represented by climatic scenarios. The research aims at evaluating the water resources changes of the mountain part of the Dniester’s catchment area at the present and in the future by the mid-21 st century (2021-2050) based on the “climate-runoff” model using meteorological observations data (up to 2018 inclusive) and scenario data (averaged data based on 14 mathematical models of the CORDEX project, RCP8.5 scenario). During the research the resources of humidification, heat (heat equivalent) and water content for modern (1989-2018) and scenario (RCP8.5, 2021-2050) climatic conditions based on application of the "climate-runoff" model were evaluated. The theoretical basis for estimating the natural (undisturbed by water management) annual runoff in this model is represented by the water-heat balance equation. The meteorological characteristics (average monthly air temperatures and precipitation) serve as input data. The runoff calculated using the water-heat balance equation is called a climatic runoff. One of the peculiarities of the research consists in the use of the vertical zoning law with respect to distribution of runoff and climatic factors of its formation. During the comparative analysis the dependence of annual runoff norms on height of the Mountain Dniester’s terrain specified in modern regulatory documents served as a basic dependence. Such dependence reflects an altitude-dependant distribution of runoff for the climatic conditions that preceded the significant impact of global warming on air temperature (until 1989). The analysis of the dependences of average long-term values of the annual runoff depending on the terrain altitude showed that the runoff changes for two studied periods (before and after 1989) are within ±12,3%. The analysis of the graphs of chronological course of annual water flow of the mountain tributaries of the Dniester made it possible to confirm the absence of statistically significant trends in their fluctuations. According to the RCP8.5 climate scenario over the period of 2021-2050 and following the results of calculations based on the “climate-runoff” model, the dependences of the average long-term altitude-related values of climatic factors and climatic runoff were retrieved. It was found that the effects of global warming decrease with increasing altitude. In the foothills (up to 200 m) the annual precipitation decreases (up to 11%), the maximum possible evaporation increases (up to 17%) and water resources decrease (up to 46%). Heat resources cease to increase and water resources cease to reduce at the altitudes over 800 m. The average deviation of the scenario and baseline values for precipitation over the estimated period will amount to 2.41% for precipitation, 5.79% for maximum possible evaporation and 8.87% for water resources. Thus, reduction of water resources in the mountainous part of the Dniester by the mid-21 st century will be insignificant. When evaluating the current state of water resources of the Mountain Dniester no significant changes were discovered, thereby not contradicting the other authors’ data.

How does the suspended sediment yield change in the North Caucasus during the Anthropocene?

<p>Processes linked to climate change and intensified anthropogenic pressure influence the environment, the hydrology and by extent the denudation processes in the Caucasus mountain belt. Quantitative assessments of sediment fluxes and their temporal evolution in this mountain region required for various environmental and engineering purposes, including the planning and maintenance of water reservoirs and other structures. This paper presents an analysis of the suspended sediment load data from almost 40 gauging stations located in the mountain part of the Terek river basin (North Caucasus, Russia). The collected dataset include river basins with various glacier cover (0%-20%) and human impact. All river basins show consistent decreases in mean annual suspended sediment load (SSL, kg/s) up to 1–2% per year during 1925–2018 (according to Mann-Kendall test). The cumulative deviation curve of the mean annual SSL for the last 60 years indicates that SSL has increased significantly from ca. 1970-1980 to 1990-2000 for the most North Caucasus rivers. However, after the 2000s mean annual values of the SSL show a stable decrease in all observed rivers. Possible mechanisms of observed changes are discussed. This study provides the data on climate-related changes in the sediment yield for a previously not investigated region.</p>

PALEOLITHIC SITE-WORKSHOP OF AKBULATOVO-3 IN THE MOUNTAIN PART OF THE BELAYA RIVER (BASHKORTOSTAN)

The discovery of the pre-Mousterian monument, dating back to the Middle Pleistocene era, in the mountain-forest zone of the Southern Urals is of great interest both for archaeology, in particular, considering the problem of time and ways of setting on the territory, and for geology, taking into account the dating of the terraces of river valleys in the mountainous part of the region. The site-workshop Akbulatovo-3 is confined to the cover deposits of the III floodplain terrace of the Belaya river, 15 m above the modern level of the river, including pebble and clastic material from quartzite in the deposits of brownish-brown loam of periglacial type of the late Risian time. The collection of items from quartzite (447 items) is represented by a variety of cores: cuboid, orthogonal, sub-cone, and biplatformed. The tools were made both by bifacial processing and on flakes, less often on amorphous plate-like chips. Among them, there are “Acheulean” forms – choppers, peaks, simple scrapers, and “Upper Paleolithic” ones – scrapers, burins, punctures, carvers, and chisel tools. Such a combination of archaic types of tools and cores with “progressive” forms of tools and cores, characteristic of the Moustier and Upper Paleolithic gives grounds to attribute the complex to the end of the Acheulean era or to the beginning of the Moustier. A similar monument, combining the Acheulean types of tools and cores with the Mousterian and Upper Paleolithic ones, was discovered on Lake Turogoyak in the Chelyabinsk region – the site Naves (Island of Vera 6a) at the porphyrite exits. This allows the authors to attribute them to a single technological tradition, called the “Akbulatov type of industry”.

Seismotectonics of the High Mountain Part of the Eastern Caucasus and the Prospects of Gas Content on the Example of the Natural Manifestation of Gas in Tsuschar Village (Dagestan)

В данной статье даны особенности геологического строения района газопроявления «Цущар» в Кулинском районе на отложениях среднеюрского возраста, предлагается геолого-структурная схема возможного формирования залежи нефти и газа. Незначительные проявления газоносности, связанные обычно с минеральными источниками и подчиненные мощной толще юрских сланцев, развитых на значительных площадях нагорного Дагестана, начали обращать на себя внимание с 1931 г., в связи с поисками месторождений легких редких газов. Анализы газов показывают повышенное содержание легких редких газов в целом ряде месторождений нагорного Дагестана. Кроме группы месторождений Южного Дагестана известен пока только один выход горючего газа в Центральном Дагестане – Кулинском районе. На него указывает в своем рукописном отчете Дагестанскому Совнархозу геолог Н. М. Леднев. Этот выход подчинен юрским сланцам, связан с нарушениями неотектонического характера, образованными в результате сейсмической активизации региона. Цель исследования. Целью наших исследований является обоснование перспектив газоносности Горного Дагестана. На изучаемой территории отмечается наличие неправильных куполовидных складок с неожиданными направлениями их осей, пересекающими основное направление складчатости, частичными местными уклонениями в залегании пластов. Методы исследования. Основными методами исследования при изучении перспектив газоносности Горного Дагестана являлись геолого-структурный, стратиграфический, морфологический, тектонический и дешифрирование аэрофотоснимков. Результаты исследования. По сравнению с Предгорным Дагестаном и Прикумским районом, Горный Дагестан был подвержен более интенсивным геотектоническим движениям, неоднократно подвергался складчатости, испытал инверсию, со значительно большей амплитудой, что привело к усиленной денудации, развитию трещиноватости и разрывов, метаморфизму пород и органических образований. Все это отрицательно влияло на сохранение нефти и газа. Можно предполагать, что многие залежи, сформировавшиеся при прохождении продуцирующими толщами главной фазы нефтеобразования, были разрушены в периоды активизации тектонической деятельности на рубеже юры и мела, мела и палеогена. В дальнейшем шла генерация, преимущественно, газообразных углеводородов, которые при особенно благоприятных условиях могли сохраниться до настоящего времени. По результатам исследований можно утверждать, что газовое проявление Цущар могло проявиться в 1622, 1652 гг. в результате сильных землетрясений, эпицентр которых располагался в пределахисследуемого района This article describes the features of the geological structure of the Tsushar gas show area in the Kulinsky region on the Middle Jurassic deposits, and proposes a geological-structural diagram of the possible formation of oil and gas deposits. Minor manifestations of gas content, usually associated with mineral springs and subordinate to a thick stratum of Jurassic shales, developed over large areas of highland Dagestan, began to attract attention from 1931, in connection with the search for deposits of light rare gases. Gas analyzes show an increased content of light rare gases in a number of fields in highland Dagestan. In addition to the group of fields in Southern Dagestan, only one outlet of combustible gas in Central Dagestan is known – the Kulinsky region. It is pointed out in his handwritten report to the Dagestan Economic Council by the geologist N. M. Lednev. This outlet is subordinate to the Jurassic shale and is associated with neotectonic disturbances formed as a result of seismic activation of the region. Aim. The purpose of our research is to substantiate the prospects for gas content in Gorny Dagestan. In the study area, there are irregular dome-shaped folds with unexpected directions of their axes crossing the main direction of folding, partial local deviations in bedding. Methods. The main research methods in the study of the prospects for the gas content of Mountainous Dagestan were geological-structural, stratigraphic, morphological, tectonic and additional aerial photographs. Research results. Compared to Piedmont Dagestan and Prikumskiy region, Gorny Dagestan was subject to more intense geotectonic movements, repeatedly underwent folding, experienced inversion, with a much higher amplitude, which led to increased denudation, the development of fracturing and fractures, metamorphism of rocks and organic formations. All of this negatively affected the conservation of oil and gas. It can be assumed that many deposits, formed during the passage of the producing strata of the main phase of oil formation, were destroyed during periods of intensified tectonic activity at the boundary between the Jurassic and Cretaceous, Cretaceous and Paleogene. In the future, there was the generation of mainly gaseous hydrocarbons, which, under especially favorable conditions, could persist to the present day. According to the research results, it can be argued that the gas manifestation of Tsushar could have manifested itself in 1622, 1652. as a result of strong earthquakes, the epicenter, which was located within the study area