Geocratic Periods

in the history of the earth, periods of the significant expansion of dry land surfaces in contrast to thalassocratic periods, which are characterized by the expansion of the area of oceans. Geocratic periods are confined to the second half of tectonic cycles, when the general crustal uplifts transform the continents previously submerged by shallow seas into dry land. They are marked by great climatic contrasts—in particular, by a considerable expansion of dry (arid) and cold climate zones. Accumulations of continental, red beds, composed of aeolian, alluvial, and lacustrine sediments from arid plains and partly from deserts, and also of glacial deposits are typical of geocratic periods. No less typical are deposits in closed and semiclosed marine basins with increased salinity and sediments in highly saline lagoons (dolomites, gypsums, salts). Geocratic periods include the end of the Silurian, a significant part of the Devonian, the end of the Carboniferous, the Permian, part of the Triassic, the Neogenic, and the Anthropogenic periods (including the present era).