Soils in Devonian and Carboniferous. Current State of Knowledge in Russia: A Review
T. V. Alekseeva
Abstract
Information on Devonian and Carboniferous paleosols is limited. In this paper, published data (about 50 sources) on findings of these paleosols mostly on the territory of paleocontinents Laurussia and Pangea are summarized. For visualization of this information, sketch maps of paleosol distribution for Devonian, Mississippian, and Pennsylvanian times have been developed. Their analysis shows that most of Devonian paleosols belonged to the groups of azonal and intrazonal soils; soils of wetlands predominated. The discoveries of Middle and Late Devonian zonal soils—Oxisols and texturally differentiated Alfisols—in the area of Voronezh High (south Russia) are unique. Most of Mississippian paleosols also belonged to azonal and intrazonal soils. The wide distribution of wetland paleosols in the Mississipian subperiod was also reflected in the increased area of coal basins (8% of land in comparison with 1% in Devonian). In the area of the Moscow sedimentary basin, along with Histosols, zonal paleosols—Spodosols and others—have been described. Pennsylvanian soil cover consisted of azonal, intrazonal, and zonal soils. In North America and Western Europe, swampy soils were still widely distributed (22% of land was occupied by coal basins). Oppositely, in the area of the Moscow sedimentary basin, Pennsylvanian paleosols of semiarid and arid ranges with palygorskite as the major clay mineral were widely present. The differentiation of Pennsylvanian soil cover of Laurussia and Pangea reflects the changes in climatic zonality of the planet with an increase in the degree of climatic contrast.