Abstract

The article considers tefroids – a kind of volcanic-sedimentary formations that occur during the eruption as a result of displacement and washing of the erupted volcanic-clastic material. Modern studies in Kamchatka and the Kuril Islands have made it possible to prove not only the synchronism of tefroid material with volcanism, but also its vast distribution, often predominating over volcanoterrigenic. Currently, in all the formations studied in detail in volcanic regions, the wide development of tefroids has been established. In terms of age, they are developed from the Early Precambrian and are formed in our time. As an example, the processes of formation of volcaniclastic formations in modern large Kamchatka volcano Bezymianny are considered. Various volcano-clastic material lies on the slopes of these volcano: deposits of pyroclastic flows, block material of lava flows and extrusive eruptions and other genetic types of volcanics. The most diverse forms of extrusive structures in the process of decompression of the material of their eruptions are involved in the formation of tefroid deposits. On the slopes of volcano and in the area of development of dry watercourses, there is a constant movement of clastic material to the foot of volcanoes. This diverse material is sorted by size, rolled around and forms well-seasoned tefroid interlayers.

Keywords

kamchatka, volcano bezymianny, tefroids, extrusion, decompression pyroclastic, eruption