Pub Date : 2019-11-08DOI: 10.31857/s0435-42812019467-76
T. Leonova, Т Д Леонова, M. Valitov, М Г Валитов, O. V. Belous, О В Белоус
The bottom topography of the studied area of the South China Sea is characterized by an uneven distribution of depths, their sharp variations and the presence of a large number of seamounts. As a result of the research conducted, bathymetric profiles, a bathymetric map and a scheme of Faye anomalies were compiled. Geomorphological zoning was conducted. Sections of bottom distinguished by morphology were identified: 1) weakly dissected slope, steep (angles up to 15) in the upper part and more gentle (57) to the bottom of the deep-water step, 2) slope eroded by fluvial processes, 3) stepped slope, 4) chains of mountains and flat-topped hills, 5) accumulative bottom of the deep-water plain. It was established that the gravitational field as a whole reflects the complex structure of the bottom, and the local forms of the underwater relief are expressed in Faye anomalies. For elevations, zones of positive anomalies of Faye are marked, and sections of canyon-like valleys were mapped by an intense negative anomaly of the gravitational field to -60 mGal. In the process of endogenous evolution of the region, the relief became more complex. The primary endogenous continental slope was almost everywhere transformed by exogenous processes. Within the shelf, the filling of the basin led to the unification of all its projections into a single raised base. A significant role in the formation of the modern relief was played by large-scale repeated sea regressions, as a result of which the formation of the sedimentary cover was interrupted by periods of its erosion with the formation of planation surfaces. The Late Pleistocene peak of the regression (1618 thousand years BP), which caused the complete drainage of the shelf areas of the region, caused the erosion of the shelf and the movement of coarse clastic material through submarine canyons and valleys.
{"title":"The South China sea continental slope morphology and its relation to the anomalous gravitational field","authors":"T. Leonova, Т Д Леонова, M. Valitov, М Г Валитов, O. V. Belous, О В Белоус","doi":"10.31857/s0435-42812019467-76","DOIUrl":"https://doi.org/10.31857/s0435-42812019467-76","url":null,"abstract":"The bottom topography of the studied area of the South China Sea is characterized by an uneven distribution of depths, their sharp variations and the presence of a large number of seamounts. As a result of the research conducted, bathymetric profiles, a bathymetric map and a scheme of Faye anomalies were compiled. Geomorphological zoning was conducted. Sections of bottom distinguished by morphology were identified: 1) weakly dissected slope, steep (angles up to 15) in the upper part and more gentle (57) to the bottom of the deep-water step, 2) slope eroded by fluvial processes, 3) stepped slope, 4) chains of mountains and flat-topped hills, 5) accumulative bottom of the deep-water plain. It was established that the gravitational field as a whole reflects the complex structure of the bottom, and the local forms of the underwater relief are expressed in Faye anomalies. For elevations, zones of positive anomalies of Faye are marked, and sections of canyon-like valleys were mapped by an intense negative anomaly of the gravitational field to -60 mGal. In the process of endogenous evolution of the region, the relief became more complex. The primary endogenous continental slope was almost everywhere transformed by exogenous processes. Within the shelf, the filling of the basin led to the unification of all its projections into a single raised base. A significant role in the formation of the modern relief was played by large-scale repeated sea regressions, as a result of which the formation of the sedimentary cover was interrupted by periods of its erosion with the formation of planation surfaces. The Late Pleistocene peak of the regression (1618 thousand years BP), which caused the complete drainage of the shelf areas of the region, caused the erosion of the shelf and the movement of coarse clastic material through submarine canyons and valleys.","PeriodicalId":35940,"journal":{"name":"Geomorfologiya","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49614418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-11-08DOI: 10.31857/s0435-42812019449-66
E. Lebedeva, Екатерина Лебедева
The characteristic features of the river network, the structure and functioning of the valleys affected by effusive and explosive volcanism, volcano-tectonic phenomena, gas hydrothermal activity and mud volcanism are revealed. It has been established that within flows and covers of effusives, the formation of new streams channels can occur not only due to backward erosion, but also as a result of the collapse of the roof of the near-surface lava tubes, which are actively used by underground runoff. A high erosion rate, a large volume of solid runoff, and a significant role of deflation in the transformation of the fluvial relief are characteristic for regions of domination of explosive activity. There valleys become zones of accumulation of volcanic material, which is gradually processed by mudflow, alluvial, aeolian and other processes. Volcanic-tectonic activity changes the rivers position, direction of streams and morphology of the valleys, leading to numerous reorganizations of the river network, as a result of which the valleys of modern watercourses often consist of uneven-age fragments. Valleys of hydrothermal zones are characterized by the active development of slope processes, which leads to the formation in them not only of sinter terraces, but also numerous landslide ones. Mud volcanic processes periodically lead to the filling and blocking of the valleys with mud breccia flows, which affects both the composition of the alluvium of watercourses and the morphology of the valleys.
{"title":"Impact of volcanic and post volcanic activity on fluvial relief","authors":"E. Lebedeva, Екатерина Лебедева","doi":"10.31857/s0435-42812019449-66","DOIUrl":"https://doi.org/10.31857/s0435-42812019449-66","url":null,"abstract":"The characteristic features of the river network, the structure and functioning of the valleys affected by effusive and explosive volcanism, volcano-tectonic phenomena, gas hydrothermal activity and mud volcanism are revealed. It has been established that within flows and covers of effusives, the formation of new streams channels can occur not only due to backward erosion, but also as a result of the collapse of the roof of the near-surface lava tubes, which are actively used by underground runoff. A high erosion rate, a large volume of solid runoff, and a significant role of deflation in the transformation of the fluvial relief are characteristic for regions of domination of explosive activity. There valleys become zones of accumulation of volcanic material, which is gradually processed by mudflow, alluvial, aeolian and other processes. Volcanic-tectonic activity changes the rivers position, direction of streams and morphology of the valleys, leading to numerous reorganizations of the river network, as a result of which the valleys of modern watercourses often consist of uneven-age fragments. Valleys of hydrothermal zones are characterized by the active development of slope processes, which leads to the formation in them not only of sinter terraces, but also numerous landslide ones. Mud volcanic processes periodically lead to the filling and blocking of the valleys with mud breccia flows, which affects both the composition of the alluvium of watercourses and the morphology of the valleys.","PeriodicalId":35940,"journal":{"name":"Geomorfologiya","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41910659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-11-08DOI: 10.31857/s0435-42812019477-87
A. Svitoch, А А Свиточ, D. Magritskiy, Д В Магрицкий, A. Porotov, А.В. Поротов, R. Makshaev, Р Р Макшаев, N. A. Tyunin, Н А Тюнин, D. Semikolennykh, Д В Семиколенных, V. Dikarev, В.А. Дикарев, T. S. Kluyvitkina, Т С Клювиткина
In the recent epoch the Kuban River delta is characterized by little distributary with low zone of lagoons and flooded areas. This accumulative plain includes different types of mesorelief such as longshore bar, channel bank, liman, plavni and channel distributaries. There are three huge geomorphological types of Kuban delta: old, young deltas and Kuban-Taman region. The main differences between them are diverse geomorphological levels, evolution of marine and fluvial forms and incomplete geomorphological development. The relief of the Kuban delta is Holocene. The main factors of its formation were large-scale fluctuations of the Azov-Black Sea basin, the flow of water and sediment of the Kuban River and its distribution in area. In the history of the development of the modern relief of the Kuban delta, there are three stages (epochs). The first is the Bugaz stage of the Holocene transgression (9.57.9 ka), when the relief of the old delta was formed. In the second stage of the Holocene transgression (Vityazevskaya, Kalamitskaya, and Dzhemetyan stages), a transitional type of relief was formed in the area adjacent to the floods of the young delta and the old delta with the formation of large buried bars. In the third stage, the systems of modern estuaries and plavni were formed, separated from the sea by a modern coastal bar.
{"title":"Evolution of the main geomorphological structure of the Holocene Kuban river delta","authors":"A. Svitoch, А А Свиточ, D. Magritskiy, Д В Магрицкий, A. Porotov, А.В. Поротов, R. Makshaev, Р Р Макшаев, N. A. Tyunin, Н А Тюнин, D. Semikolennykh, Д В Семиколенных, V. Dikarev, В.А. Дикарев, T. S. Kluyvitkina, Т С Клювиткина","doi":"10.31857/s0435-42812019477-87","DOIUrl":"https://doi.org/10.31857/s0435-42812019477-87","url":null,"abstract":"In the recent epoch the Kuban River delta is characterized by little distributary with low zone of lagoons and flooded areas. This accumulative plain includes different types of mesorelief such as longshore bar, channel bank, liman, plavni and channel distributaries. There are three huge geomorphological types of Kuban delta: old, young deltas and Kuban-Taman region. The main differences between them are diverse geomorphological levels, evolution of marine and fluvial forms and incomplete geomorphological development. \u0000The relief of the Kuban delta is Holocene. The main factors of its formation were large-scale fluctuations of the Azov-Black Sea basin, the flow of water and sediment of the Kuban River and its distribution in area. In the history of the development of the modern relief of the Kuban delta, there are three stages (epochs). The first is the Bugaz stage of the Holocene transgression (9.57.9 ka), when the relief of the old delta was formed. In the second stage of the Holocene transgression (Vityazevskaya, Kalamitskaya, and Dzhemetyan stages), a transitional type of relief was formed in the area adjacent to the floods of the young delta and the old delta with the formation of large buried bars. In the third stage, the systems of modern estuaries and plavni were formed, separated from the sea by a modern coastal bar.","PeriodicalId":35940,"journal":{"name":"Geomorfologiya","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45426883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-11-08DOI: 10.31857/s0435-428120194102-112
V. Chichagov, В П Чичагов
Examples of relief studies by seven prominent Russian soil scientists, representatives of the Dokuchaev school, are presenterd. Geomorphological issues, ideas and concepts in the works of soil scientists of the XX century. showed their high professional interest in geomorphology. The beginning of the geomorphological research of Russian soil scientists was laid by the great Russian researcher V. V. Dokuchaev. Geomorphological views of V. V. Dokuchaev were ahead of the V. M. Davis' concept of the geographic cycle. Soil-geomorphological studies of S. S. Neustruev partially supplemented the concept of V. M. Davis. B. B. Polynov proved the necessity of attracting geomorphological methods and techniques when conducting soil studies, used geomorphological principles in the deduction of the three laws of the distribution of weathering crusts. I. P. Gerasimov created the theory of morphostructure and morphosculpture, introduced the idea of three macrocycles in the history of the formation of the Earth's landscapes. All the researchers cited in the article conducted detailed complex studies using geodesy methods. Scientists were able to identify a large array of new geomorphological data from the classification of microrelief to the adjustment of the main laws of geomorphology. The main feature of the scientific activity of Russian soil scientists-geomorphologists was the Dokuchaev school that gave rise to all them. It was from the Dokuchaev's principles and approaches that the mentioned scientists started and developed and passed to their students and followers. The well known Russian soil scientist and geomorphologist I. P. Gerasimov completed the century-long period of the geomorphological studies by soil scientists started by V. V. Dokuchaev.
{"title":"Geomorphology in the works of Russian soil scientists-geographers XX c. From V.V. Dokuchaev to I.P. Gerasimov","authors":"V. Chichagov, В П Чичагов","doi":"10.31857/s0435-428120194102-112","DOIUrl":"https://doi.org/10.31857/s0435-428120194102-112","url":null,"abstract":"Examples of relief studies by seven prominent Russian soil scientists, representatives of the Dokuchaev school, are presenterd. Geomorphological issues, ideas and concepts in the works of soil scientists of the XX century. showed their high professional interest in geomorphology. The beginning of the geomorphological research of Russian soil scientists was laid by the great Russian researcher V. V. Dokuchaev. Geomorphological views of V. V. Dokuchaev were ahead of the V. M. Davis' concept of the geographic cycle. Soil-geomorphological studies of S. S. Neustruev partially supplemented the concept of V. M. Davis. B. B. Polynov proved the necessity of attracting geomorphological methods and techniques when conducting soil studies, used geomorphological principles in the deduction of the three laws of the distribution of weathering crusts. I. P. Gerasimov created the theory of morphostructure and morphosculpture, introduced the idea of three macrocycles in the history of the formation of the Earth's landscapes. All the researchers cited in the article conducted detailed complex studies using geodesy methods. Scientists were able to identify a large array of new geomorphological data from the classification of microrelief to the adjustment of the main laws of geomorphology. The main feature of the scientific activity of Russian soil scientists-geomorphologists was the Dokuchaev school that gave rise to all them. It was from the Dokuchaev's principles and approaches that the mentioned scientists started and developed and passed to their students and followers. The well known Russian soil scientist and geomorphologist I. P. Gerasimov completed the century-long period of the geomorphological studies by soil scientists started by V. V. Dokuchaev.","PeriodicalId":35940,"journal":{"name":"Geomorfologiya","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42779902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-11-08DOI: 10.31857/s0435-42812019488-101
A. V. Seleznevа, А.В. Селезнева, I. S. Dedovа, И С Дедова
The article is devoted to a detailed morphogenetic analysis of erosion topography of the right Volga river bank (Volgograd region, Russia). The estimation of the factors in the development of erosion processes: lithological, geomorphological, climatic, biotic. It is established that the general trends of the development and the propagation of gully systems depend on the zonal conditions, and their specificity from structural-lithological and geomorphological features of the area. The actual basis for the work, based on data from field observations, interpretation of satellite imagery, morphometric processing of topographic maps. The obtained results were used for compiling maps, morphometric characteristics of the relief and zoning of the right bank of the Volgograd city according to the intensity of erosion processes. It was established that the studied area is among the most erosion-affected territories in the European part of Russia with the average erosion density of the network from 0.10.3 up to 34 km/km2. Comparison of factors determining the intensity of the evolution and morphology of gully systems led to the conclusion that modern intensification of erosion is the result of economic activities.
{"title":"Morphogenetic analysis of erosion topography the right Volga river bank (Volgograd region, Russia)","authors":"A. V. Seleznevа, А.В. Селезнева, I. S. Dedovа, И С Дедова","doi":"10.31857/s0435-42812019488-101","DOIUrl":"https://doi.org/10.31857/s0435-42812019488-101","url":null,"abstract":"The article is devoted to a detailed morphogenetic analysis of erosion topography of the right Volga river bank (Volgograd region, Russia). The estimation of the factors in the development of erosion processes: lithological, geomorphological, climatic, biotic. It is established that the general trends of the development and the propagation of gully systems depend on the zonal conditions, and their specificity from structural-lithological and geomorphological features of the area. The actual basis for the work, based on data from field observations, interpretation of satellite imagery, morphometric processing of topographic maps. The obtained results were used for compiling maps, morphometric characteristics of the relief and zoning of the right bank of the Volgograd city according to the intensity of erosion processes. It was established that the studied area is among the most erosion-affected territories in the European part of Russia with the average erosion density of the network from 0.10.3 up to 34 km/km2. Comparison of factors determining the intensity of the evolution and morphology of gully systems led to the conclusion that modern intensification of erosion is the result of economic activities.","PeriodicalId":35940,"journal":{"name":"Geomorfologiya","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43158665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-11-08DOI: 10.31857/s0435-4281201943-26
C. Ollier, К Д Оллиер, C. Pain, К Ф Пайн
Mountains are topographic features caused by erosion after vertical uplift or mountain building. Mountain building is often confused with orogeny, which today means the formation of structures in fold belts. The common assumption that folding and mountain building go together is generally untrue. Many mountains occur in unfolded rocks, granites and volcanic rocks, so there is no direct association of folding and mountain building. In those places where mountains are underlain by folded rocks the folding pre-dates planation and uplift. The age of mountains is therefore not the age of the last folding (if any) but the age of vertical uplift. Since mountains are not restricted to folded rocks, lateral compression is not required to explain the uplift. A compilation of times of uplift of mountains around the world shows that a major phase of tectonic uplift started about 6 Ma, and much uplift occurred in the last 2 Ma. This period is known as the Neotectonic Period. It is a global phenomenon including mountains on passive continental margins, and those in deep continental interiors. Several hypotheses of mountain building have problems with this timing. Some fail by being only able to make mountains out of folded rock at continental margins. Many translate the vertical uplift into lateral compression, but vertical uplift alone can create mountains. The Neotectonic Period has important implications for geomorphology, climate and global tectonics. In geomorphology it does not fit into conventional theories of geomorphology such as Davisian or King cycles of erosion. Neotectonic uplift might initiate several cycles of erosion, but most planation surfaces are much older than the Neotectonic Period. The increasing relief associated with Neotectonic uplift affected rates of erosion and sedimentation, and also late Cenozoic climate. The Neotectonic Period does not fit within plate tectonics theory, in which mountains are explained as a result of compression at active margins: mountains in other locations are said to have been caused by the same process but further back in time. This is disproved by the young age of uplift of mountains in intercontinental and passive margin positions. Subduction is supposed to have been continuous for hundreds of millions of years, so fails to explain the world-wide uplifts in just a few million years. Geomorphologists should be guided by their own findings, and refrain from theory-driven hypotheses of plate collision or landscape evolution.
{"title":"Neotectonic mountain uplift and geomorphology","authors":"C. Ollier, К Д Оллиер, C. Pain, К Ф Пайн","doi":"10.31857/s0435-4281201943-26","DOIUrl":"https://doi.org/10.31857/s0435-4281201943-26","url":null,"abstract":"Mountains are topographic features caused by erosion after vertical uplift or mountain building. Mountain building is often confused with orogeny, which today means the formation of structures in fold belts. The common assumption that folding and mountain building go together is generally untrue. Many mountains occur in unfolded rocks, granites and volcanic rocks, so there is no direct association of folding and mountain building. In those places where mountains are underlain by folded rocks the folding pre-dates planation and uplift. The age of mountains is therefore not the age of the last folding (if any) but the age of vertical uplift. Since mountains are not restricted to folded rocks, lateral compression is not required to explain the uplift. \u0000A compilation of times of uplift of mountains around the world shows that a major phase of tectonic uplift started about 6 Ma, and much uplift occurred in the last 2 Ma. This period is known as the Neotectonic Period. It is a global phenomenon including mountains on passive continental margins, and those in deep continental interiors. Several hypotheses of mountain building have problems with this timing. Some fail by being only able to make mountains out of folded rock at continental margins. Many translate the vertical uplift into lateral compression, but vertical uplift alone can create mountains. \u0000The Neotectonic Period has important implications for geomorphology, climate and global tectonics. In geomorphology it does not fit into conventional theories of geomorphology such as Davisian or King cycles of erosion. Neotectonic uplift might initiate several cycles of erosion, but most planation surfaces are much older than the Neotectonic Period. The increasing relief associated with Neotectonic uplift affected rates of erosion and sedimentation, and also late Cenozoic climate. \u0000The Neotectonic Period does not fit within plate tectonics theory, in which mountains are explained as a result of compression at active margins: mountains in other locations are said to have been caused by the same process but further back in time. This is disproved by the young age of uplift of mountains in intercontinental and passive margin positions. Subduction is supposed to have been continuous for hundreds of millions of years, so fails to explain the world-wide uplifts in just a few million years. \u0000Geomorphologists should be guided by their own findings, and refrain from theory-driven hypotheses of plate collision or landscape evolution.","PeriodicalId":35940,"journal":{"name":"Geomorfologiya","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47579039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-11DOI: 10.31857/s0435-42812019357-67
O. Kuznetsova, Ольга Александровна Кузнецова, Y. Saprykina, Я В Сапрыкина
Effect of bar position on underwater profile of sandy beach was studied at the timescale of one storm using the xBeach numerical model. Beach profiles were extracted from the bathymetry of the Shkorpilovtsy beach (the Bulgarian coast of the Black Sea). Computed results were verified by field measurements. The largest shoreline retreat occurred in the first hour of a storm. For the chosen wave regime (largest wave height 1.5 m, wave period 10.5 s), an equilibrium profile was formed after 6 hours. The resulting profile contained an underwater terrace with the slope close to that of the theoretical equilibrium profile. It was shown that the position of the underwater bar affects the shoreline retreat rate. The smallest and the largest shore retreat occur if bar crest is located at a distance about 0.7–0.8 and 0.5 of the deep water wavelength, correspondingly. It was found that the shoreline retreat depends on the height of infragravity waves and mean wave period: the smaller mean wave period and the higher infragravity waves near the coast, the smaller is the retreat of the coastal line. Distance of seaward sediment transfer is directly relates to the height of large waves near the shore.
{"title":"Modeling the dynamics of a sand beach governed by the wave and underwater bar interaction","authors":"O. Kuznetsova, Ольга Александровна Кузнецова, Y. Saprykina, Я В Сапрыкина","doi":"10.31857/s0435-42812019357-67","DOIUrl":"https://doi.org/10.31857/s0435-42812019357-67","url":null,"abstract":"Effect of bar position on underwater profile of sandy beach was studied at the timescale of one storm using the xBeach numerical model. Beach profiles were extracted from the bathymetry of the Shkorpilovtsy beach (the Bulgarian coast of the Black Sea). Computed results were verified by field measurements. The largest shoreline retreat occurred in the first hour of a storm. For the chosen wave regime (largest wave height 1.5 m, wave period 10.5 s), an equilibrium profile was formed after 6 hours. The resulting profile contained an underwater terrace with the slope close to that of the theoretical equilibrium profile. It was shown that the position of the underwater bar affects the shoreline retreat rate. The smallest and the largest shore retreat occur if bar crest is located at a distance about 0.7–0.8 and 0.5 of the deep water wavelength, correspondingly. It was found that the shoreline retreat depends on the height of infragravity waves and mean wave period: the smaller mean wave period and the higher infragravity waves near the coast, the smaller is the retreat of the coastal line. Distance of seaward sediment transfer is directly relates to the height of large waves near the shore.","PeriodicalId":35940,"journal":{"name":"Geomorfologiya","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44067555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-11DOI: 10.31857/s0435-42812019319-35
S. Shvarev, С В Шварев
The research area is located in the Northern part of the Karelian Isthmus between Lake Ladoga and the Gulf of Finland of the Baltic Sea. The terrain features are closely related to the tectonic structure of the crystalline basement, partially covered with thin deposition layer of the Last Glaciation and Holocene mostly. Accumulative forms are rarely but strongly correlated with the tectonic structure also. Most expressive features of accumulative topography are esker ridges that stretch for tens of kilometers. Analysis of eskers spatial distribution shows their close connection with the structural plan of the crystalline basement. One of the ridges under study was described in three sections where a lot of deformations in soft sediments, accompanied by deformations of the esker’s topography (in one case) were found. The nature and stratigraphic position of deformations indicates their appearance during the period of existence of the Baltic Ice Lake after the retreat of the ice sheet. Post-sedimentary deformations were accompanied by partial re-deposition of sedimentary strata. Deformations are represented by several types and generations. The ensembles of faults and fold deformations in the esker deposition kinematically connected with each other and coinciding along the strike with the structural lineaments demonstrate the influence of the activated tectonic structure to the formation of the sedimentary cover. The conjugation of normal and thrust faults, the presence of several “event horizons” with traces of liquefaction testify to the seismotectonic genesis of deformations and several strong earthquakes that occurred at different stages of the existence of the Baltic Ice Lake in the period 13.0–11.6 thousand years BP.
{"title":"Postglacial seismogenic deformations of an esker in the Northern Karelian Isthmus (south-east Fennoscandia)","authors":"S. Shvarev, С В Шварев","doi":"10.31857/s0435-42812019319-35","DOIUrl":"https://doi.org/10.31857/s0435-42812019319-35","url":null,"abstract":"The research area is located in the Northern part of the Karelian Isthmus between Lake Ladoga and the Gulf of Finland of the Baltic Sea. The terrain features are closely related to the tectonic structure of the crystalline basement, partially covered with thin deposition layer of the Last Glaciation and Holocene mostly. Accumulative forms are rarely but strongly correlated with the tectonic structure also. Most expressive features of accumulative topography are esker ridges that stretch for tens of kilometers. Analysis of eskers spatial distribution shows their close connection with the structural plan of the crystalline basement. One of the ridges under study was described in three sections where a lot of deformations in soft sediments, accompanied by deformations of the esker’s topography (in one case) were found. The nature and stratigraphic position of deformations indicates their appearance during the period of existence of the Baltic Ice Lake after the retreat of the ice sheet. Post-sedimentary deformations were accompanied by partial re-deposition of sedimentary strata. Deformations are represented by several types and generations. The ensembles of faults and fold deformations in the esker deposition kinematically connected with each other and coinciding along the strike with the structural lineaments demonstrate the influence of the activated tectonic structure to the formation of the sedimentary cover. The conjugation of normal and thrust faults, the presence of several “event horizons” with traces of liquefaction testify to the seismotectonic genesis of deformations and several strong earthquakes that occurred at different stages of the existence of the Baltic Ice Lake in the period 13.0–11.6 thousand years BP.","PeriodicalId":35940,"journal":{"name":"Geomorfologiya","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48879397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-11DOI: 10.31857/s0435-42812019383-90
D. Subetto, Дмитрий Александрович Субетто, M. Potakhin, Максим Сергеевич Потахин, M. Zobkov, Михаил Борисович Зобков, A. Tarasov, А Ю Тарасов, T. Shelekhova, Татьяна Станиславовна Шелехова, V. Gurbich, В А Гурбич
The GIS-based reconstructions of Lake Onego development in the Late Glacial (14500–12300 yrs ago) were performed. Reconstructions have been based on the deglaciation model of the Lake Onego depression, digital elevation model of the lake depression, SRTM model of its drainage basin and on the data obtained from the palaeolimnological studies of numerous lake sediment cores. This allowed us to distinguish six main stages of the lake development for which a series of detailed schemes were produced. 1. Formation of the ice-dammed lake as a result of the ice sheet retreating (14.5 cal ka BP). 2. Emerging of the southern and central parts of the lake basin from the ice cover (14.0 cal ka BP). 3. The maximum development of the proglacial lake (13.3 cal ka BP). The lake area in this period was around 33 000 km2. 4. The first regression (13.2 ka BP). 5. The second regression (12.4 ka BP). 6. The third regression (12.3 ka BP), when the area of the lake dropped to 18 000 km2. We created detailed digital maps of the main stages of Lake Onego development during the Late Glacial and calculated the spatial parameters of the lake. The quantitative data obtained in this study would be used in estimation of the volumes of the lake and outflow discharges in the past. Maps are available in electronic form.
{"title":"Lake Onego development in the late glacial assessed with the use of GIS technologies","authors":"D. Subetto, Дмитрий Александрович Субетто, M. Potakhin, Максим Сергеевич Потахин, M. Zobkov, Михаил Борисович Зобков, A. Tarasov, А Ю Тарасов, T. Shelekhova, Татьяна Станиславовна Шелехова, V. Gurbich, В А Гурбич","doi":"10.31857/s0435-42812019383-90","DOIUrl":"https://doi.org/10.31857/s0435-42812019383-90","url":null,"abstract":"The GIS-based reconstructions of Lake Onego development in the Late Glacial (14500–12300 yrs ago) were performed. Reconstructions have been based on the deglaciation model of the Lake Onego depression, digital elevation model of the lake depression, SRTM model of its drainage basin and on the data obtained from the palaeolimnological studies of numerous lake sediment cores. This allowed us to distinguish six main stages of the lake development for which a series of detailed schemes were produced. 1. Formation of the ice-dammed lake as a result of the ice sheet retreating (14.5 cal ka BP). 2. Emerging of the southern and central parts of the lake basin from the ice cover (14.0 cal ka BP). 3. The maximum development of the proglacial lake (13.3 cal ka BP). The lake area in this period was around 33 000 km2. 4. The first regression (13.2 ka BP). 5. The second regression (12.4 ka BP). 6. The third regression (12.3 ka BP), when the area of the lake dropped to 18 000 km2. We created detailed digital maps of the main stages of Lake Onego development during the Late Glacial and calculated the spatial parameters of the lake. The quantitative data obtained in this study would be used in estimation of the volumes of the lake and outflow discharges in the past. Maps are available in electronic form.","PeriodicalId":35940,"journal":{"name":"Geomorfologiya","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49538031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-11DOI: 10.31857/s0435-42812019346-56
N. Koronkevich, Н.И. Коронкевич, S. Dolgov, С.В. Долгов
On the example of a southern part of the Russian Plain the surface slope runoff, the runoff from the hydrographic network and snow melt river runoff are considered. Based on the analysis of the data by water balance stations and the correlation of surface slope runoff values from different lands to the zonal river runoff value, the zonal values of the spring surface slope flow from separate lands located on loam and sandy loam soils are determined. Within agricultural lands there are fall plowed fields and non-plowed in autumn (stubble, layland, winter crops, perennial grasses). By the beginning of the spring flood, the soil at autumn-plowed fields is loosened and reduces the runoff, while on the fields that were not plowed in the autumn soil is compacted. In addition, the microtopography created by autumn plowing also contributes to the runoff reduction. The smallest surface slope runoff occurs under the forest. Differences in runoff increase in the direction from the southern part of the forest zone to the steppe areas. Taking into account the land composition and the mechanical composition of the soils, the weighted average values of the surface slope runoff were obtained for the period of the long-time average annual flow calculation (late 19th century and early 1960s). It is shown that subsequently there was a decrease in the spring surface slope runoff, initially as a result of the autumn plowing increase, and more recently, mainly as a result of changes in meteorological conditions, especially during the cold season (air temperature rising, frequent thaws, increased infiltration). In the overall structure of the spring river flood, along with a decrease in the share of surface slope runoff, the share of surface runoff formed in the hydrographic network increases, and especially the flow of infiltration origin (verhovodka and underground runoff). In the steppe zone the structure of river flow has changed most significantly.
{"title":"On the hydrological role of the relief in the southern part of the Russian plain","authors":"N. Koronkevich, Н.И. Коронкевич, S. Dolgov, С.В. Долгов","doi":"10.31857/s0435-42812019346-56","DOIUrl":"https://doi.org/10.31857/s0435-42812019346-56","url":null,"abstract":"On the example of a southern part of the Russian Plain the surface slope runoff, the runoff from the hydrographic network and snow melt river runoff are considered. Based on the analysis of the data by water balance stations and the correlation of surface slope runoff values from different lands to the zonal river runoff value, the zonal values of the spring surface slope flow from separate lands located on loam and sandy loam soils are determined. Within agricultural lands there are fall plowed fields and non-plowed in autumn (stubble, layland, winter crops, perennial grasses). By the beginning of the spring flood, the soil at autumn-plowed fields is loosened and reduces the runoff, while on the fields that were not plowed in the autumn soil is compacted. In addition, the microtopography created by autumn plowing also contributes to the runoff reduction. The smallest surface slope runoff occurs under the forest. Differences in runoff increase in the direction from the southern part of the forest zone to the steppe areas. Taking into account the land composition and the mechanical composition of the soils, the weighted average values of the surface slope runoff were obtained for the period of the long-time average annual flow calculation (late 19th century and early 1960s). It is shown that subsequently there was a decrease in the spring surface slope runoff, initially as a result of the autumn plowing increase, and more recently, mainly as a result of changes in meteorological conditions, especially during the cold season (air temperature rising, frequent thaws, increased infiltration). In the overall structure of the spring river flood, along with a decrease in the share of surface slope runoff, the share of surface runoff formed in the hydrographic network increases, and especially the flow of infiltration origin (verhovodka and underground runoff). In the steppe zone the structure of river flow has changed most significantly.","PeriodicalId":35940,"journal":{"name":"Geomorfologiya","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41812081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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