(or lithological-paleogeographic maps), maps that represent spatial changes in the lithological composition and thicknesses of sedimentary and sedimentary-volcanogenic rocks of a certain geological age depending on tectonic conditions and on the physicogeographic conditions of their sedimentation.
Different systems of symbols are used for combined representation of a set of features on a single map: the lithological composition of deposits is represented by hachures, the thickness of deposits by solid lines (isopachs), paleogeographic conditions by shading or color, the direction of movement of detrital material and currents by movement-indicating lines (arrows), and typical authigenic minerals and organic residues which determine the boundaries of lithological, facies, and climatic zones by non-scaled conventional symbols. All conventional symbols, with explanations, are put in the legend, or table of the map’s conventional symbols.
Lithofacies maps represent, within the region being mapped, the distribution of land and sea during a particular geological age, the presumed relief of the land and sea floor, the position of the valleys of ancient rivers, the areas of various types of continental, lagoon, and marine sediment accumulations, the climatic zonation that existed within the particular territory, and many other characteristics of the physicogeographic conditions in the past. The features that are the basis for identifying paleogeographic zones and conditions are determined by facies analysis. A series of lithofacies maps which covers the entire sedimentary section of a region without any gap (age by age) makes it possible to reconstruct the history of sediment accumulation and the history of development of the physicogeographic environment and to identify their interrelationships; it also makes it possible to identify the conditions of habitation and spreading of flora and fauna and the conditions of formation of deposits of sedimentary minerals.
Significant advances in working out methods of compiling lithofacies maps in the USSR are reflected in the four-volume Atlas of Lithological-Paleogeographic Maps of the USSR, which was published in 1967–69 by the Academy of Sciences of the USSR and the Ministry of Geology of the USSR under the editorship of A. P. Vinogradov.
REFERENCESNalivkin, D. V. Uchenie o fatsiiakh, vols. 1–2. Moscow, 1955–56.
Rukhin, L. B. Osnovy obshchei paleogeografii. Moscow, 1959.
Metody sostavleniia litologo-fatsial’nykh i paleogeograficheskikh kart. Novosibirsk, 1963.
A. B. RONOV