Coastal dynamics of the Gulf of Kalamita (Western Crimea)

The performed research showed that since the first third of the 20th century until today the beach width at various sections of the Gulf of Kalamita has decreased two-to fourfold, and at some of them beaches have totally disappeared. The average coast erosion rate for the last 100 years has been 1.3 m/yr, with the maximum being 7.8 m/yr. These processes are accompanied with depletion of debris on the beach and underwater slope, erosion of bench deposits, and destruction of coastal structures. This is due to deficiency of beach-forming material resulted from intense economic management in the coastal area. Implementation of scientifically and technically sound coastal protection projects is essential to preserve the beaches of the Gulf of Kalamita.

MORPHOLOGICAL CONDITIONS OF THE COASTAL ZONE OF THE BARRIER SYSTEM OF “WINGED FORELAND” KINBURNSKA–POKROVSKA–DOVGY

In the coastal zone of the oceans, there are various coastal systems, among which the most specific are “winged forelands”. Within the Black Sea coast there are four “winged forelands”: Tendra–Dzharylgach, Kinburnska–Pokrovska–Dovgiy, Burnaska–Budatska and Lebedyna–Ustrychna, which named by same structural ones. The purpose of the publication is to systematize the primary information about the morphological features of the coastal zone of the barrier system type ‘winged foreland” Kinburnska–Pokrovska–Dovgy which was obtained during field research.During the natural research in 2019, within the most typical areas of the coastal zone, reference benchmarks and morphological profiles were laid and recorded by a GPS. The total length of the coastal system is about 35 km, within its boundaries there are 7 benchmarks, which contains for 1 benchmark per 5 km, and a systematic geomorphological survey of 20 profiles (1 profile per 1.75 km) is carried out. Relevant indicators suggest that the results of the research are reliable.Morphologically, the studied system is a “winged foreland”, within which there are four structural and morphological elements: Kinburnska Spit, Frontal Coast or “headland”, Pokrovska Spit with the islands of Kruglyi and Dovhyi. Kinburnska Spit is a free accumulative coastal form located in the northwestern part of the Kinburn Peninsula. Morphogenetically, it is an arrow that develops in the conditions of bilateral feeding by beach sediments. The Frontal Coast or “headland” is the central component, within which the sand massifs of the Kinburn Peninsula go directly to the coastal zone. Pokrovska spit with the islands of Krugliy and Dovhiy is a relict generation, which is genetically an ancient accumulative form divided into three components. All these components are located on the surface of the base of the ancient coastal form, and their development occurs in conditions of limited supply of beach sediments. The front of the Pokrovsky Peninsula with the Sukha Spit and the Island Bar “Zagreba” is a modern accumulative generation that is actively increasing in size and advancing towards the waters of Tendra Bay.Key words: coastal systems, “winged foreland”, coastal zone, underwater slope, shore, coastal systems, foredunes У береговій зоні Світового океану існують різноманітні берегові системи, серед яких найбільш специфічні «крилаті миси». У межах узбережжя Чорного моря виділяються чотири «крилаті миси»: Тендра–Джарилгач, Кінбурнська–Покровська–Довгий, Бурнаська–Будацька та Лебедина–Устрична. Мета публікації полягає у систематизації та оприлюдненні первинної інформації про морфологічні особливості берегової зони бар’єрної системи типу «крилатий мис» Кінбурнська–Покровська–Довгий, отриманої під час польових досліджень 2018–2021 рр. Загальна довжина дослідженої берегової системи близько 35 км, в її межах закладено 7 репер-них стаціонарних ділянок та проводиться систематична геоморфологічна зйомка на 20 профілях, положення яких зафіксовано за допомогою GPS-приймача. Розроблена система стаціонарних ділянок і геоморфологічних профілів дозволяє надійно проводити довготермінові спостереження в масштабі 1:10000. Відповідні показники дозволяють вважати, що результати проведених досліджень є достовірними.У морфологічному відношенні досліджувана система є «крилатим мисом», в її межах виділяються чотири структурно-морфологічні елементи: Кінбурнська коса, Фронтальний берег, Покровська коса з островами Круглий та Довгий, Фронт Покровського півострова із Сухою косою та острівним баром «Загреба».Кінбурнська коса – це вільна акумулятивна берегова форма, розташована у північно-західній частині Кінбурнського півострова. В морфогенетичному відношенні це стрілка, яка розвивається в умовах двостороннього живлення прибережно-морськими наносами. Фронтальний берег, або «лобище», є центральним складовим елементом, у межах якого безпосередньо до берегової зони виходять піщані масиви Кінбурнського півострова. Покровська коса з островами Круглий та Довгий є реліктовою генерацією, яка в генетичному відношенні є давньою акумулятивною формою, поділеною на три складники. Всі перелічені складники розташовані на поверхні цоколю давньої берегової форми, а їх розвиток відбувається в умовах обмеженого живлення прибережно-морськими наносами. Фронт Покровського півострова із Сухою косою та острівним баром «Загреба» являє собою нову акумулятивну генерацію, яка активно збільшується у розмірах та висувається в бік акваторії заток.Ключові слова: берегові системи, «крилатий мис», підводний схил, берег, підводний вал, авандюна.

Tectonic ledges at the bottom of Lake Ladoga

<p>For the last several years, the Institute of Limnology RAS has been conducting geological and geomorphological studies of the bottom of Lake Ladoga, the largest lake in Europe. Beginning in 2018, these studies began to use underwater photo and video camera, created at INOZ RAS. The use of this new research tool led to the discovery of a number of new facts of the structure of the bottom of Lake Ladoga. In particular, during the 2020 field season, the authors discovered in several areas of Lake Ladoga the existence of underwater subvertical scarps, composed of bedrocks. At the same time, the submarine towing boat stood in one place, and the camera vertically upward from depths of about 100 - 120 meters to depths of 20 - 30 meters. During this entire rise, the camera recorded the bedrock ledge with vertical and even negative angles. No traces of glacier processing were found, which indicates the Holocene age of the found scarps. In 2020, such ledges were found in 3 regions of Lake Ladoga: in a depression near the  Pitkyaranta in the northeastern part of the lake, in the Suuri-Viroluoto trench in the northern part of the lake and on the western underwater slope of Valaam Island. A mention of the possibility of the existence of such ledges (up to the first tens of meters in height) in the northern part of Lake Ladoga is found in the works of V.A. Rumyantsev and V.N. Rybakina (2012), A.V. Amantov (2014), Bolshiyanov (2018). M.A.Naumenko, who studied the underwater slope of Valaam Island, considered the maximum angle of this slope to be 60 degrees (2019). We found sub-vertical ledges up to 100 meters high. In addition, these scarps are in spatial relationship with the existing tectonic faults, confirming their significant fault component. The presence of young vertical high ledges at the bottom of Lake Ladoga indicates powerful young tectonic movements in this region.</p>

LANDSCAPE STRUCTURE OF THE WESTERN COAST OF SEVASTOPOL

The information about the landscape structure of the western coast of Sevastopol. Landscape studies (summer 2020) were conducted by detailed study of key sites using landscape profiling. In the landscape structure of the study area identified 8 bottom natural complexes (BCN). The capes at a depth of 0.5-5 m are characterized by underwater slope landscapes with boulder and boulder heaps and bedrock outcrops dominated by Carpodesmia crinita and Treptacantha barbata. Between the capes at these depths, underwater slope landscapes formed by sandy sediments, devoid of benthic vegetation, where individual clumps are also dominated by Carpodesmia crinita and Treptacantha barbata. An underwater coastal slope composed of coarse-clastic sediments dominated by Treptacantha barbata, and with alternating pebble-gravel with battered shell sediments dominated by Phyllophora crispa, was recorded at a depth of 5–10 m. A weakly sloping plain composed of gravel-sandy sediments with broken shells, dominated by Phyllophora crispa, can be traced at a depth of 10–15 m. The formation of its landscape structure is influenced by both the natural features of the coastal zone and economic activities in the adjacent territory.

COMPUTER MODELING OF THE SAND BODIES DEPOSITIONAL HISTORY OF THE MIDDLE JURASSIC PETROLEUM PLAY (BY THE EXAMPLE OF THE GERASIMOVSKOE FIELD, WESTERN SIBERIA)

The present paper describes the DIONISOS software package (Beicip-Technologies), where the reconstruction of the accumulation conditions and facies modeling of sand reservoirs Yu10, Yu9, Yu8, Yu7 and Yu6 of the Tyumenskaya Formation and carbonaceous-clay members acting as fluid seals within the Gerasimovskoye oil and gas condensate field located in the south of the Parabel district of the Tomsk region. Reconstructions of facies environments make it possible to consistently restore conditions and create a general principled model of the accumulation of sandy-argillaceous deposits of the Middle Jurassic PP in a given territory. Polyfacies deposits of the Bajocian are represented by sands of distributaries and stream-mouth bars, underwater slope of delta, above-water and underwater delta plains, argillaceous-carbonaceous sediments of floodplain lakes, bogs, marshes and lagoons, clays formed at the border of the above-water and underwater deltaic plains, silt deposits of above-water and underwater delta plains, prodelta clays. As a result of the 3D facies model construction, it is shown that the subcontinental sedimentary environments of sand reservoirs Yu10–Yu8 are replaced by deltaic and floodplain-lacustrine-boggy ones, and the formation of Yu7–Yu6 reservoirs occurs in conditions of coastal plain, periodically flooded by the sea. In total, 5 lithotypes of sand deposits have been identified, 1 – argillaceous-carbonaceous, 2 – argillaceous and 1 – silty. Computer facies 3D modeling of the sand bodies assemblage (hydrocarbon reservoirs) of the Bajocian age for the Gerasimovskoye oil and gas condensate field has been performed.

COASTAL MONITORING OF THE VERBYANAYA SPIT BY SATELLITE DATA

The Verbyanaya spit is the south-western part of the sea edge of the Kuban river Delta, which was formed during the last 200 years. Сomplex monitoring studies including analysis of remote sensing data and cartographic material were performed for estimation of modern development trends of this accumulative form, coastal dynamics, the intensity of erosion-accumulative processes and the effectiveness of coast protection structures. The coastal dynamics of the Verbyanaya spit during last 150 years was determined by combined action of natural and anthropogenic factors. For last half a century the coastline of spit western part came forward to 200-400 m and the east spit coast retreated to 30-200 m. Economic development of adjacent area (natural gas exploration and production) has caused the need to stabilize the coast, and coastal protected dam was built in 2007. Monitoring showed that spit coast stabilized after creation of the dam, but changes of the underwater slope relief continued. Currently Verbyanaya spit develops as natural-anthropogenic system.

REFRACTIONOF WIND WAVES IN MESHWATER ZONNE BY THE SHORES OF ANY UNDERWATER SLOPE MORFOSTRUCTURE

The graphical analytical technique for refraction waves in coastal water areas under condition of water slope relief in shapes of bathymetry charts. The given technique is based on results of theoretical studies in water areas refractions in sea bays made by the authoress. The convergences data obtained are suited for foolproof calculations results for proposed methods of wave tank supervision along with natural of measurements and numerical results. The given technique make it possible to recreate the approximate picture wave field refraction on the coastal zone up to the border of waves turnover.