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geomorphology,study of the origin and evolution of the earth's landforms, both on the continents and within the ocean basins. It is concerned with the internal geologic processes of the earth's crust, such as tectonic activity and volcanism that constructs new landforms, as well as externally driven forces of wind, water, waves, and glacial ice that modify such landforms. Geomorphology developed from the works of James HuttonHutton, James,
1726–97, Scottish geologist, chemist, and naturalist. He was initially attracted to chemistry; he entered the legal profession at the Univ. of Edinburgh; turned to medicine, as it closely resembled chemistry; and then became a farmer to allow him to study
..... Click the link for more information. and James Playfair in the 18th cent.; G. K. Gilbert described landform evolution; William Morris Davis developed the geomorphic cycle, set forth in his Geographic Essays (1909). By the 1970s, geomorphology had grown to include the environmental problems involved in landform processes, including subsidencesubsidence,
lowering of a portion of the earth's crust. The subsidence of land areas over time has resulted in submergence by shallow seas (see oceans). Land subsidence can occur naturally or through human activity.
..... Click the link for more information. , landslideslandslide,
rapid slipping of a mass of earth or rock from a higher elevation to a lower level under the influence of gravity and water lubrication. More specifically, rockslides are the rapid downhill movement of large masses of rock with little or no hydraulic flow, similar to
..... Click the link for more information. , and coastal processes (see coast protectioncoast protection,
methods used to protect coastal lands from erosion. Beaches can exist only where a delicate dynamic equilibrium exists between the amount of sand supplied to the beach and the inevitable losses caused by wave erosion.
..... Click the link for more information. ), which all affect humans who live in certain susceptible regions. Satellite images and data help geomorphologists to describe and map landforms and observe rapid or slow changes on the earth's surface. Development of mathematical models of landform processes have influenced the direction of modern geomorphic research. Geomorphology principles also have been applied to the study of landform development of other planets and moons of the solar system, based on images sent back to earth by flyby and orbiting satellites.
the science of the relief of the earth’s surface.
Geomorphology studies the relief of land and of the ocean and sea floor from the standpoint of its external (physiognomic) appearance, origin, age, history of development, and present dynamics as well as of the laws of grouping and distribution of the forms that make up the relief. Geomorphology treats the relief observed in the present geological age as the result of the entire preceding development of the earth’s surface.
The surface of the earth is a boundary with the earth’s crust on one side and the hydrosphere and atmosphere on the other. Internal and external agents, which produce endogenous and exogenous relief-forming processes, are simultaneously acting upon the earth’s surface. Tectonic movements and magmatic action are among the endogenous processes caused by the interior forces of the earth. The exogenous processes, which are nourished by the sun’s radiant energy, include weathering, the work of surface waters and glaciers, wind, and the activity of animal and plant organisms. Gravitational processes, which are also significant in forming relief, occur under the direct influence of the force of gravity on the surface of the earth. The mutual gravitational pull of earth, sun, and moon, which causes tides in seas and oceans and in the solid body of the earth, as well as changes in the angular velocity of the earth’s rotation around its axis, has a great effect on the earth as a whole. The activities of human society are also an important factor in bringing about changes in the earth’s relief. In different places and at different times the structure of internal and external forces, as well as their intensity and direction, fluctuates over a broad range and causes in each given locality and at each given moment a general (upward or downward) development of relief and of the specific features of its formation.
It is one of the fundamental principles of geomorphology that relief is to be studied as a geographic component, closely interrelated and causally connected with other components and geographic conditions in general. Relief is not only influenced by other factors, but it also exerts an influence on them and through them, on itself.
The place of geomorphology among the earth sciences is determined by the complex interrelationships between the lithosphere, atmosphere, hydrosphere, and biosphere. The data and methods of geology are used to explain the dependence of relief on the geological structure and development of the portion of the earth’s crust being studied. The data of physical geography, climatology, hydrology, oceanography, soil science, and geobotany are used to explain the dependence of relief on physical geographic conditions in general and on particular natural components. Geophysical data are used to study the physical nature of the processes of relief formation and the interaction of relief with the solid, liquid, and gaseous envelopes of the earth.
A number of branches may be identified within geomorphology. General geomorphology examines the broadest questions on the formation of relief and deals with the entire complex of geomorphological indicators in a synthetic manner. Particular geomorphology studies relief with reference to one or several particular geomorphological indicators. Regional geomorphology is the study of the concrete relief of different parts of the earth’s surface, such as continents, oceans, seas, and countries. The major regional features of the earth’s relief serve as the subject of study in planetary geomorphology. Paleogeomorphology, a special branch of geomorphology, is concerned with the investigation of the relief (often buried) of past geological periods and the elucidation of the history of the formation of the earth’s surface over long periods of geological time. In applied geomorphology the theoretical principles for applying the results of geomorphological research to the solution of national economic problems are worked out.
General geomorphology includes a number of branches, the most important of which are land geomorphology, which studies the relief of continental surfaces, and marine geomorphology, which studies the relief of the ocean and sea floor.
Particular geomorphological disciplines include structural and climatic geomorphology. Structural geomorphology is the study of morphostructures, that is, relief forms that arise as a result of the historically developing conflicting interaction of exogenous and endogenous factors, with the endogenous factors predominating. Climatic geomorphology deals with morphosculptures, that is, relief forms that are created primarily by exogenous processes interacting with all other relief-forming factors. Structural geomorphology includes branches devoted to the study of the role of active tectonics in relief formation and of the role of already formed relatively passive geological structures, which appear in the plate of the earth’s surface owing to the uneven denudation of rocks having different compositions. Climatic geomorphology is subdivided into several branches, which deal with relief form complexes developing under different physical geographic conditions, that is, in regions with humid and semihumid climates or present-day or ancient nival climates or in polar, subpolar, arid, or karst regions.
The geometry, kinematics, and dynamics of relief, in that order, are particular indicators that may be quantitatively expressed. In the geometry of relief attention is focused on the study of the physiognomic appearance of relief. It includes morphography, which deals with the outline of relief forms, and morphometry, which is concerned with the size of forms, which can be characterized by different quantitative indexes. The kinematics of relief deals with the general characteristics of form changes of the earth’s surface independently of the forces that generate these changes. The geometry and kinematics of relief are an introduction to dynamic geomorphology, which is the study of the physical nature of topographic development in relation to factors acting upon it. Dynamic geomorphology is broken up into branches dealing with different geomorphological processes, such as slope, fluvial, karst suffosion, glacial, frozen ground, eolian, lacustrine, and marine processes. Dynamic geomorphology also deals with the manifestation of tectonic and volcanic processes in relief. In the particular disciplines and branches indicated relief is studied analytically, and only in the aggregate do they provide a synthetic representation of relief and its development. The methods of such scientific disciplines as geology, glaciology, geocryology, soil mechanics, hydrodynamics, and aerodynamics are employed widely in geomorphological research. Many theoretical problems are worked out with the help of mathematical research methods.
The basic working method of geomorphology consists of field work and geomorphological surveying for the compilation of general and special-purpose geomorphological maps. In addition to field work stationary and experimental studies are conducted of geomorphological processes. In field work cartographic, geodetic, aerial, geophysical, and other instrument observation methods are employed. Thus, in geomorphological investigations of the sea floor navigation equipment, echo sounding, seismic-refraction sounding, and special devices for taking soil samples at great depths are used.
The data of geomorphology are used in prospecting for various, especially placer, mineral deposits (prospecting geomorphology), in planning industrial, civil, and water-power installations, highways, railroads, and seaports (engineering geomorphology), and in developing measures for the economic management of land, its agricultural use, and the prevention of soil-gully erosion. Geomorphological research results serve as the basis for both branch and composite geographic investigations.
Historical survey. Geomorphology became an independent scientific discipline in the late 19th and early 20th century, when two schools of geomorphology arose—the American school led by W. M. Davis and the European school (mainly German), founded by F. von Richthofen, A. Penck, and W. Penck. The theoretical concepts of the American school were expressed most fully in Davis’ studies on geographic cycles and those of the European school, in W. Penck’s studies on the upward and downward development of relief (based on the morphological analysis of slopes) and on piedmont steps. Later on, there was a noticeable tendency abroad to overcome the abstractness and dogmatism of the old concepts and to create a theoretical foundation for geomorphology based on the study of structural and climatic geomorphology (the French scientists J. Bourcart, J. Büdel, A. Dresch, A. Cailleux, J. Tricart, A. Cholley). However, certain geomorphologists abroad continue to elaborate ideas in which relief formation is analyzed without due consideration for specific physical geographic conditions, for example, the English geomorphologist L. King’s studies on the universal significance of pediplain formation processes, and his denial of the role of climate as one of the determining factors in the formation of relief. In the last few decades foreign scientists have devoted much attention to the problems of dynamic geomorphology and morphometry, for example, the Canadian scientists A. Strahler and A. Scheidegger.
In Russia the foundations of geomorphology were laid down by P. P. Semenov-Tian-Shanskii, P. A. Kropotkin, V. V. Dokuchaev, I. D. Cherskii, I. V. Mushketov, S. N. Nikitin, D. N. Anuchin, A. P. Pavlov, and V. A. Obruchev, and others. During the Soviet period much progress was made in the geomorphological knowledge of the territory of the USSR and in the development of theoretical concepts (A. A. Borzov, I. S. Shchukin, la. S. Edel’shtein, A. A. Grigor’ev, I. P. Gerasimov, K. K. Markov, B. L. Lichkov, N. I. Nikolaev, V. A. Varsanof eva, S. S. Shul’ts). Soviet scientists are developing fruitful ideas on geomorphological levels (K. K. Markov), the geotexture, morphostructure, and morphosculpture of the earth (I. P. Gerasimov and Iu. A. Meshcheriakov), morphological complexes (I. S. Shchukin), and geomorphological cycles (Iu. A. Meshcheriakov, Iu. F. Chemekov). General conceptions about the origin and development of both the relief of the earth as a whole and the relief of the world ocean floor are being formulated on the basis of recent data concerning the structure of the earth’s crust and mantle (O. K. Leont’ev, B. L. Lichkov, G. B. Udintsev, and V. E. Khain). Much work has been done on relief classification, on the formation of fluvial, karst, glacial, frozen ground, and eolian relief, and on the morphology of coasts (S. G. Boch, N. A. Gvozdetskii, V. P. Zenkovich, G. A. Maksimovich, D. G. Panov, A. I. Popov, and B. A. Fedorovich). There has been a great deal of geomorphological investigation of the territory of the USSR (S. S. Voskresenskii, K. I. Gerenchuk, M. V. Karandeeva, V. A. Dement’ev, N. V. Dumitrashko, P. K. Zamorii, L. I. Maruashvili). Much work has also been done on the methods of compiling maps and their legends (Z. A. Svarichevskaia, D. V. Borisevich, A. I. Spiridonov, V. V. Ermolov, I. I. Krasnov). Improvements are being made in different methods of studying relief—cartographic methods (V. P. Filosofov), aerial methods (V. P. Miroshnichenko, M. N. Petrusevich), geodetic and geophysical methods and stationary and experimental research (M. I. Iveronova, N. I. Makkaveev, G. K. Tushinskii). Special attention is being given to questions of the geometry, kinematics, and dynamics of relief (D. L. Armand, A. S. Devdariani, Iu. K. Efremov, V. V. Longinov).
The coordination of work in geomorphology on the international level is performed by the commissions and sub-commissions of the International Geographical Union (for applied geomorphology, geomorphological mapping methods, and other fields). Problems of geomorphology are on the agendas of international geological congresses and the International Association for the Study of the Quaternary Period.
In the USSR the work of geomorphologists is coordinated by the Joint Geomorphological Committee under the Academy of Sciences of the USSR. Questions related to geomorphology are discussed at the conferences of the Geographic Society of the USSR. Abroad, articles on geomorphology are published in the journals Zeitschrift für Geomorphologie (Leipzig-Berlin, 1925) and Revue de la géomorphologie dynamique (Paris, since 1950) as well as in geographic journals. In the USSR articles on geomorphology are published mainly in periodicals (Izvestiia Geograficheskogo obshchestva SSSR and Izvestiia AN SSSR, seriia geograficheskaia) and in collections and periodicals issued by branches and sections of the Geographic Society of the USSR, by universities and other higher educational institutions, and by scientific and industrial organizations. The journal Geomorfologiia began publication in 1970.
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A. I. SPIRIDONOV