Thalassocratic Period

in earth history, a period of widespread distribution of seas on the surfaces of the modern-day continents. Thalassocratic periods are juxtaposed to geocratic periods, which are characterized by a significant increase in land area. Thalassocratic periods occurred in the middle of tectonic cycles (stages), when crustal subsidence predominated over the earth’s surface, resulting in the inundation of large areas of the continents in almost all regions. The enlarged area of the hydrosphere fostered the development of a wet marine climate, with little temperature variation. During thalassocratic periods, rock accumulations were primarily marine sedimentary strata; among them carbonaceous rocks played a large part. Among the thalassocratic periods are the Middle Cambrian, Late Silurian, and Middle Devonian, the beginning of the Late Devonian, and the Early Carboniferous and Late Cretaceous.