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(or recent tectonics), a branch of geotectonics devoted to the study of tectonic processes that first appeared during Neocene and Anthropogene times. These processes have led to changes in the structure of the earth’s crust and to the development of new structural forms and the activation of ancient structures; the forms and structures are often reflected in the modern relief of the earth.
Among the many scientists who have advanced ideas and generalizations concerning neotectonic movements are the Russian and Soviet scientists M. V. Lomonosov, N. A. Golovkinskii, A. P. Karpinskii, A. P. Pavlov, V. A. Obruchev, B. L. Lichkov, G. F. Mirchink, N. I. Nikolaev, S. S. Shul’ts, and Iu. A. Meshcheriakov; the Germans L. von Buch, W. Penck, H. Stille, and B. Gutenberg; the Swedes de Geer and E. O. Runeberg; and the Finnish scientists W. Ramsay, M. Sauramo, and V. Tanner.
In 1937, Shul’ts first used the term “recent tectonics” in explaining the formation of the modern relief of the Tien-Shan by manifestations of recent tectonic processes. In 1948, Obruchev proposed that neotectonics be made an independent branch of geology. In 1950, Nikolaev isolated the period of intensified tectonic movements in the Neocene and Anthropogene into an independent recent tectonic stage in the development of the earth’s crust. The maximum activation of recent tectonic movements in different structural elements of the earth’s crust (for example, on the continental platforms, in the zones of orogeny and taphrogeny, and in modern geosynclinal regions) occurred at different times (late Oligocene, Neocene, and Anthropogene). This has given rise to debate regarding the lower boundary of the recent tectonic stage and how it differs qualitatively from more ancient tectonic stages.
Among the various methods employed in neotectonics to study tectonic processes are historical geological methods, which use historical evidence of the subsidence or uplift of coasts, such as the inundation of old structures and shallowing of ancient harbors, and tectonic and geomorphological methods, which involve the analysis of morphometric data, the study of river valleys and the hydrographic network, observation of deformations of peneplanation planes, and the like. Other methods include geophysical (seismic, electrometric), historical-archaeological, and biogeographic (nature of the distribution of particular species or groups of plants and animals) methods. Modern movements are studied by precision instrument methods (repeated leveling, triangulation). Various techniques for the mathematical processing of data are used extensively.
A major achievement of neotectonics was the Map of the Recent Tectonics of the USSR on a Scale of 1:5,000,000, edited by Nikolaev and Shul’ts (1959). Later, general maps of the neotectonics of various regions of the USSR were published, including the Map of the Recent Tectonics of the West Siberian Plain, edited by I. P. Varlamov (1969), and the Tectonic Map of theArctic and Subarctic, edited by I. P. Atlasov (1969). In addition, different versions of maps showing the velocity of modern vertical movements of the earth’s crust for the western half of the European part of the USSR have been published (1955–70). The studies of the International Union for Quarternary Research (INQUA; since 1953) and the commission for the study of recent tectonic movements of the International Union of Geodesy and Geophysics (since 1960) resulted in the creation of models of national neotectonic and seismotectonic maps and national maps of modem movements. International maps, such as the Map of Modern Vertical Movements of the Earth’s Crust in Eastern Europe, edited by Iu. A. Meshcheriakov (1972), have also been compiled.
The resolution of the theoretical problems of neotectonics is closely linked to the resolution of practical tasks. These tasks include the designing of permanent engineering structures (dams, ports); the planning of water supply systems; the construction of petroleum and gas pipelines; the search for petroleum, gas, and placer deposits; and the prediction of earthquakes.
REFERENCESObruchev, V. A. “Osnovyne cherty kinetiki i plastiki neotektoniki.” In his book Izbrannye raboty po geografii Azii, vol 2. Moscow, 1951.
Nikolaev, N. I. Noveishaia tektonika SSSR. Moscow-Leningrad, 1949.
Nikolaev, N. I. Neotektonika i ee vyrazhenie v strukture i rel’efe territorii SSSR. Moscow, 1962.
Shul’ts, S. S. Analiz noveishei tektoniki i rel’ef Tian’-Shania. Moscow, 1948.
Sovremennye tektonicheskie dvizheniia zemnoi kory i metody ikh izucheniia: Sb. st. Moscow, 1961.
Noveishie dvizheniia, vulkanizm i zemletriaseniia materikov i dna okeanov. Moscow, 1969.
Sovremennye dvizheniia zemnoi kory, nos. 1–5. Moscow-Tartu, 1963–73.
N. I. NIKOLAEV and O. A. RAKOVETS