抄録
SYNOPSIS: -For the formation of coal deposits certain conditions in which the sediments including plant remains accumulated are first necessary; they are essen-tially the development of the coal basin and suffiicient supply of plant materials. Subsi-dence of the basin and climate adequate for plant growth might be ultimately influenced by tectonic control through the ages. Throughout the world coals occur in scattered localities in each of the major post-Silurian stratigraphic subdivisions. The distribution of the coal fields is discussed in the relation with tectonic parts of the earth crust.
The coal fields of the world are grouped into three types: the orogen (marginal sinking and interior deep), shelf (stabile and labile shelves) and kratogen (marginal district and interior trough) types. The coal fields of each type are also characterized by sedimentary facies, coal reserves and geologic structures. Our knowledge of coal-forming plants is obtained mainly from plant fossils found in the strata above and below the coal seams, and partly from coal and coal balls. On the basis of these sufficient informations the vicissitude of the past forests was first summarized. The considerable formation of workable coal seams in the world corresponds to the flourishment of land plants in the past. Some problems concerning the coal-forming plants of Late Paleozoic and Tertiary coals are discussed.
