Between 1949 and 1957, the author participated in a variety of geological investigations closely related to the study of mineral resources in the southern part of Krasnoyarsk Krai. The task initially assigned to the author, namely the establishment of a Central Petrographic and Mineralogical Laboratory in the city of Krasnoyarsk, subsequently evolved into a broader program of specialized research aimed at the systematic development of geological survey and exploration work in the southern part of the krai. This required the creation of the Krasnoyarsk Special Expedition, which, in addition to carrying out general regional geological studies in southern Krasnoyarsk Krai, was also charged with the specific task of expanding the region’s raw-material base, particularly through the discovery of new types of mineral resources. From 1949 to 1954, the author carried out a variety of integrated studies, including both specialized research and the solution of practical geological problems. Beginning in 1954, the author’s work on the geology of southern Krasnoyarsk Krai was supported by the Council for the Study of Productive Forces of the Academy of Sciences of the USSR, which ensured the continuity of investigations during 1955–1957. To facilitate completion of the geological studies of southern Krasnoyarsk Krai initiated in 1949, laboratory facilities were provided by Chernivtsi State University in 1954–1955 and by the Siberian Branch of the Academy of Sciences of the USSR in 1956–1957. This monograph summarizes the results of research conducted over the preceding eight years (1949–1957). It is based on a series of reports of various types submitted by the author to the archives of the Krasnoyarsk Geological Administration and prepared for publication. 段落 5 It should be emphasized that the data presented in this work are the result of the author's own field investigations. These investigations covered the entire Minusinsk Intermontane Depression and extended beyond its boundaries into the Eastern Sayan region (including the Kyzyl–Kazyr interfluve and adjacent areas), as well as parts of the Kuznetsk Alatau (its eastern slope) and the Western Sayan (its northern foothills). All observational data were obtained by the author during geological mapping at various scales for different production purposes, as well as through specialized studies conducted alongside the development of geological survey work. In describing the characteristics of alkaline rocks, these personal observations were supplemented by the results of survey and exploration operations. The accumulation over many years of information on the geological structure of the Devonian basins within the Minusinsk Intermontane Depression has made it possible to present in a consolidated form the new data obtained by the author concerning the geology, tectonics, and volcanism of southern Krasnoyarsk Krai. The study of tectonics and volcanism has confronted us with many important problems, all of which, to a greater or lesser extent, require resolution. The foremost task is to clarify the principal stratigraphic characteristics of the Devonian volcanic formations, which are widely distributed and therefore play a special role in the structure of the basin. Stratigraphic studies of volcanic rock sequences are fundamentally important both for a correct understanding of the basic structural problems of the basin and for resolving a series of questions concerning the development of volcanism. The second task is to investigate the products of Devonian and Jurassic volcanic activity. In this field, we currently possess a great diversity of information that has not yet been adequately synthesized. Existing publications contain contradictory interpretations of these data, making a comprehensive reexamination necessary. The third task is to determine the distinctive features of the geological structure of the Devonian basin and to reveal the principal characteristics of its evolutionary history. Although many questions remain unresolved, it may nevertheless be asserted that substantial progress has already been achieved in this area. The fourth task, representing the natural culmination of the investigation, is to analyze the relationship between volcanism and tectonic movements. This is one of the most difficult problems, and it would be unrealistic to expect a universally applicable solution based solely on the materials available from the Minusinsk Intermontane Depression. Nevertheless, in certain respects, resolving specific problems within this particular region may prove more meaningful than seeking solutions of entirely general applicability.