Zonation

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zonation

[zō′nā·shən]
(ecology)
Arrangement of organisms in biogeographic zones.
(geology)
The condition of being arranged in zones.

Zonation

 

(geographic), the pattern of differentiation of the geographic sphere (landscape) of the earth, manifest in the sequential and definite change of geographic belts and zones and resulting primarily from differences in the amount of solar energy reaching particular latitudes on the earth’s surface.

Zonation is also characteristic of most of the components and processes of the natural geographic regions—climatic, hydrological, geochemical, and geomorphological processes; the soil, plant cover, and animal life; and to some extent the formation of sedimentary rocks. A decrease in the angle of the sun’s rays as they strike the earth from the equator to the poles creates broad latitudinal belts of radiation: a tropical zone, two temperate zones, and two cold zones. The formation of analogous belts, especially climatic and geographic belts, is related to the characteristics of the atmosphere and atmospheric circulation, and these are strongly influenced by the distribution of land and oceans, which is not zonal. The differentiation of natural zones on land depends on the pro-portion of heat and moisture, which changes not only with latitude but also from the coastal area to the continental interior (patterns of sectionalization). Thus it is possible to speak of horizontal zonation, which is particularly well shown by the latitudinal zonation on the plains of the USSR. Each geographic belt and sector has its spectrum and sequential order. Zonation is also expressed in the regular progression of altitudinal zones, or belts, in mountains, which is originally determined by a nonzonal factor, the relief; moreover, definite spectra of altitudinal zones are characteristic of particular belts and sectors. Both horizontal and vertical zonation are expressed in oceans (by consecutive changes in temperature, salinity, biocomponents), over which geographic belts extend.

Zonation of thermal conditions was recognized as early as classical times. Climatic and plant zonation, including altitudinal zonation, was established by the German scientist A. von Humboldt. Zonation was first defined as a fundamental law of differentiation of major natural complexes by V. V. Dokuchaev in 1898.

E. N. LUKASHOVA

References in periodicals archive ?
(2004): A new conodont zonation of the Pragian in the stratotype area (Barrandian, central Bohemia).
(1994): New Emsian conodont zonation (lower Devonian).
Table 1 Particular decisions made for each thematic map Theme Mean of charted visualization Scale Symbology Epicenters Paper/web Regional Circle/sphere visualizer Tectonics Paper Regional Geology conventions Zonations Paper Regional Polygons with transparency Historical Paper Regional Circle Seismicicty and national Seismic Paper/web Regional Intervals/isolines Hazard visualizer and natio- combined with nal color value continu- ous variation Theme Visual No.
Within the Geographic Information System (GIS) implemented for this research, five themes have been mapped: earthquake epicentres, tectonics, seismogenic zonation, historical seismicity and seismic hazard.
Zonation exists at a general level; however, at the micro-scale farmers plant using local site information.
Ordovician chitinozoan zonation of Quebec and western Newfoundland.
The low copper concentrations found in these samples make them ideal for studying the performance of the new mapping technique for trace elements to determine whether zonation of copper at low concentrations can be identified.
It is considerably greater than formerly recognized and Globorotalia crassaformis may be more widely used in the Pliocene-Quaternary zonations.
The purpose of this paper is the biostratigraphic revision of conodont faunas from the Wenlock-Ludlow boundary in the Prague Synform and their correlation with the recently proposed standardized conodont zonation. The revision is based both on previous and newly obtained conodont data.
Lower Permian shallow-water conodont zonation is therefore more detailed than pelagic zonation.