CHANGE IN THE GLOBAL DENUDATION BASE IN THE LATE MESOZOIC AND CENOZOIC AND ITS INFLUENCE ON THE FORMATION OF GEOMORPHOLOGICAL STRUCTURE IN AREAS WITH VARIOUS NEOTECTONIC REGIMES

The data on regional geology, stratigraphy and geomorphology accumulated by now permit one to compile a reliable and fairly complete model of changes in the World Ocean level in the interval from the Cretaceous period to the present. Global changes in the level of the World Ocean are primarily associated with slow and prolonged (107–108 y.) manifestations of plate tectonics (spreading of the ocean floor and decrease in the area of continents against the background of the formation of mountain relief due to collision processes at their borders) and faster, but short-term (103–106 y.) processes associated with the withdrawal of large amounts of water during the formation of large continental ice sheets and its return to the World Ocean during interglacial periods. The impact of the tectonic factor throughout the entire period under review was unidirectional, but uneven and led to intermittent decrease in the World Ocean level from 250–300 m above the present level to the current level, taken as 0 m. Prolonged periods of stable position of the World Ocean level in the second half of the Cretaceous, Paleogene and Early Neogene at 300, 250, 200 and 150 m led to the formation of regional peneplanation planes near these levels. Moreover, younger surfaces have never completely cut off the previous, higher level, leaving its relics in the form of table elevations on the surface of the younger peneplain. In tectonically passive areas, the hypsometric position of these geomorphological elements and associated sediments has stratigraphic significance, allowing the researchers to estimate their age, and in the case of their displacement, to evaluate the age and amplitudes of neotectonic movements.

Geomorphology and Neotectonics of Southwestern Crimea

—The area of southwestern Crimea includes the ending of the Crimean Mountains that arose during the neotectonic activation at the place of the Cretaceous–Paleogene denudation plain and the adjacent shallow-water carbonate sedimentation basin. The Crimean Mountains are one of the links of the Alpine–Himalayan orogenic belt formed during the collision of the Eurasian, African, and Indo–Australian plates. Their area includes late Cenozoic marine terraces of the complete Mediterranean series and a staircase of Neogene, Paleogene and Cretaceous planation surfaces over them. The planation surfaces of different ages resulted from the successive lowering of the World Ocean level. Their subsequent deformations make it possible to outline the area of the neotectonic uplifting and determine its parameters. The main mechanism of the neotectonic activation was the thrust of the East Black Sea microplate under the Scythian one and the formation of a ramp fold structure. The amplitude of the neotectonic uplifting of southwestern Crimea for the past 2 Myr varies from 0 to 800 m, i.e., is up to 0.04 mm/year. The recent neotectonic structure of the area is formed by the northern flank of the ramp fold; it is a monocline of NW dip consisting of “keys” of NW strike separated by the latest faults with vertical displacements of 10 to 120 m. The uplifting of the area and the lowering of the World Ocean level led to a widespread of denudation surfaces. Their good preservation makes it possible to refine the sequence of neotectonic events, whose first pulses reached the study area in the Oligocene, and the main activation phase began in the Pliocene.

Application of GNSS-reflectometry for monitoring world ocean level

Рассмотрен вопрос применения метода ГНСС-рефлектометрии для мониторинга уровня Мирового океана. Выполнен эксперимент по оценке точности определения уровня Атлантического океана на станции Роскоф (Франция). По результатам проведенного эксперимента установлено, что средняя квадратическая погрешность, определенная по результатам сравнения трехмесячных измерений, полученных по показаниям мареографа радарного типа и метода ГНСС-рефлектометрии, составила 0,617 м при среднем арифметическом значении 0,048 м.

Лагунные берега Тихоокеанской России: факторы эволюции и природопользование

Прибрежная зона восточно-арктических и дальневосточных морей Тихоокеанской России имеет широкий спектр морфогенетических типов берегов. Наиболее полно среди них представлены лагунные берега. Эволюция лагун связана с повышением уровня Мирового океана. На этом фоне отмечено увеличение штормовой активности, что приводит к существенному преобразованию рельефа: формированию новых проливов и островов, преобразованию дельт. Существенно проявление географической зональности в динамике берегов. Показано, что в Охотском море ледовый фактор играет важную роль в морфологии и динамике лагун, а природные условия формирования побережий позволяют считать их субарктическими. Прибрежно-морское природопользование носит разносторонний характер: добыча рыбы, водорослей и беспозвоночных гидротехническое строительство разработка прибрежно-морских россыпей тяжелых металлов освоение бальнеологических ресурсов. Широко развиты марикультура и экологический туризм. Лагунные берега формируются иногда в условиях активного техногенного воздействия.The coastal zone of the East Arctic and Far-Eastern seas of Pacific Russia has a wide range of the morphogenetic types of the shores. The lagoon shores are most fully presented among them. The lagoons evolution is caused by the world ocean level increase. An increase in storm activity leads to a significant transformation of the terrain. New straits and islands are formed and the deltas are transformed. The manifestation of the geographic zonality in the dynamics of shores is essential. It is shown that the ice factor plays an important role in the morphology and dynamics of lagoons in the Sea of Okhotsk. The natural conditions for the formation of coasts make it possible to consider them as subarctic. The coastal-marine management is of versatile nature: catch of fish, algae and invertebrates hydrotechnical construction mining of seashore placers of the heavy metals development of balneal resources. The mariculture and eco-tourism are well represented. Sometimes the lagoon shores are formed under conditions of active technogenic impact.

Spatial diversity and time variability of erosion and accumulation processes on the unconsolidated cliffs of the Wolin Island (Southern Baltic - Pomeranian Bay)

<p>During the period of climate change affecting the increase in the frequency of extreme events, the problems of the functioning of the sea coasts become very important. The process of raising the World Ocean level directly threatens coastal areas which are inhabited by more than half of population.This situation is also observed on the Polish coast. The very intense and often uncontrolled tourist and economic development of this region requires the introduction of protection systems aimed at limiting the adverse changes caused by extreme processes. Anthropogenic coastal transformations commonly contribute to the modification of natural morphogenetic processes. As a result, the development of the coastal zone goes in an unknown direction.</p><p>The current problems related to the functioning of cliff coasts prompted the authors to conduct research on the impact of storm surges on the transformation of the morphology of the unconsolidated cliffs of Wolin Island. The research consisted of annual measurements of cliff morphology using terrestrial laser scanning (TLS) in the period 2013-2019. The obtained measurement series allowed to demonstrate spatial diversity and time variability of erosion and accumulation processes in various hydrometeorological conditions. Differential analyzes allowed to quantify of the sediment budget on different sections of the cliffs. Based on the proposed denudation indicators, spatial and temporal differentiation of cliff dynamics and efficiency was presented.</p>

New result on the history of the Azov Sea in the Holocene

The paper analyzes the results of integrated studies, obtained in the recent years, of bottom sediments and coastal transects in the Sea of Azov. The changes of natural conditions, taking place in its sea basin during the last 20 thousand years, are coordinated with the chronology of the World Ocean level fluctuations. The stages of the sea level increase, caused by the glacier shields melting, are considered. Due to the fact, it is noted that the change of the level of the World Ocean made a decisive impact on the formation of the Sea of Azov current water area conditions.

To the methods of geomorphological research (geomorphological lessons of the Caspian)

The main focus of the article is the significance of the geomorphological method for the reconstruction of paleogeographic events that took place in the Late Pleistocene and Holocene. The specific data obtained as a result of applying this method are given. A reasonable curve of the Caspian Sea level fluctuations in the Holocene was compiled. A risk zone has been defined, within which the level of the Caspian Sea will fluctuate in the future, under modern physics-geographical conditions, which is fundamental importance when planning any economic measures in the coastal zone. Predictions were made and later justified of the Caspian Sea level fluctuations in the 20thearly 21st centuries. The climatic nature of the Caspian transgressions was confirmed. Obtained were new data on the evolution of the shores of the Caspian Sea under rising level conditions, which can be used when forecasting the development of the shores of other seas in the conditions of the present-day rise of the World Ocean level.