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The abstract presents new results of geophysical, geological and geoarcheological studies of the Quaternary sediments developed in the coastal zone of the eastern Gulf of Finland (Baltic Sea). Within the area of the Narva-Luga Klint Bay (southern coast of the Gulf of Finland) and in the vicinity of Vysokinskoe Lake (north coast of the Gulf of Finland) ground penetrating radar (GPR) profiling was carried out. GPR systems SIR-2000 and SIR-4000 (GSSI) equipped with antennas of different frequencies (400, 200 and 70 MHz) were used. Different combinations of GPR tools provide different resolution and depth of penetration. Profiling was accompanied by geodetic survey. Total length of GPR profiles was about 80 kilometers. For the first time, a significant amount of high-quality data was obtained on land within the area of coastal marine and glacial deposits distribution. This became possible due to the use of vehicle for profiling. All data were processed by computer center of VSEGEI using RADAN software. As a result of observed data analysis several GPR units were defined. Separation of GPR units was based upon sediment composition and structural differences. This method performs great possibilities for identifying predominantly sandy sediments of different genetic types such as glacial, fluvioglacial, marine and aeolian. Some of detected sediments form relict landforms. In addition, some of revealed borders were identified as erosion horizons. As a result preserved relict landforms and absolute heights of detected units and horizons were determined. These studies allowed to divide deposits accumulated during different stages of the Baltic Sea development in the Late Pleistocene and Holocene and to determine possible paleo-sea levels. Obtained data are well correlated with the Neolithic sites discovered by archaeological research in this area. Studies were carried out in the frame of project № 17-77-20041 of Russian Science Foundation. [ABSTRACT FROM AUTHOR]

Results of VSEGEI research have shown that coastal zone of the Gulf of Finland is strongly affected by erosion processes.The use of drones turned upside down the methods of modern environmental monitoring. Thus, a small quadrocopter makes possible to get an orthophoto of the terrain relatively cheap and very fast comparing to traditional aerial photography methods. Usage of drones in Russian Federation are not regulated by law yet, but we widely use them in our investigations. Regular surveys in the study area allows us to monitor the dynamics of the coastline and additionally the coastal underwater ramparts.Upper part of the coastal geological sequence consists of easily erodible Quaternary deposits represented mainly by Holocene marine sands and Late Pleistocene sandy and clayey loam of glacial origin. Maximal rate of erosion escarpment retreat is about 5 m in vicinity of Kurortny District. For the years without extreme storm events, the mean rates of retreat are less than 0.5 m/year.During long-term observations with the involvement of remote sensing data showed that the coastal zone in the area of the village of Bolshaya Izhora is one of the most dynamic parts of the coast. From 2011 to 2018, the movement of the coast projection (waves) is 180 m. The wavy shore contour moves in the eastern direction with an average speed of 25 m / year. The last analyzes of the dynamics of the coastal zone of Kotlin Island showed (data from the WWII Aerial Photos of August 15, 1939 and modern satellite imagery) that the development has a similar principle: straightening the coast with capes erosion and filling (accumulation) located of the adjacent bays to the East. During 76 years the average erosion rates are 1.2–1.6 m / year.This research was carried out in frame of project № 17-77-20041 of Russian Science Foundation. [ABSTRACT FROM AUTHOR]

Onshore of the eastern Gulf of Finland (Baltic Sea) within the area of the Narva-Luga Klint Bay (lowland between the Narva and Luga rivers) a multiple depositional sequence was formed during the ice sheet degradation. It is represented mainly by periglacial accumulative sandy landforms. During the Holocene the lowland was substantially transformed by coastal-marine and alluvial processes. A relict of presumably glaciofluvial landform (a series of pebble-sand clinoforms forming the glacial delta according to GPR data) (Ryabchuk et al., 2018) located in the area of Holocene deposits development was dated using OSL method. According to this dating the age of subsurface part of the glaciofluvial landform is 13-10.8 thousand cal. yrs. BP. The glaciofluvial deposits are covered by a thin sandy layer which was formed 8.1 ± 0.8 thousand cal. yrs. BP according to OSL dating of the sample collected at the height range from +11.8 to +12.3 m.s.l. Consequently this sandy layer was formed during the first transgression of the Littorina Sea, the maximum of which was achieved 7.5 thousand cal. yrs. BP. The study was supported by Russian Science Foundation (project № 17-77-20041).References:Ryabchuk, D.V., Sergeev, A.Yu., Gerasimov, D.V., Kriiska, A., Nordqvist, K., Budanov, L.M., Kovaleva, O.A., Zhamoida, V.A., Anisimov, M.A., Terekhov, A.V. New data on the postglacial development of Narva-Luga Klint Bay (eastern Gulf of Finland): Results of geoarchaeological research // Journal of Coastal Conservation. 2018 P. 1–20 [ABSTRACT FROM AUTHOR]