Many iron ore and polymetallic deposits are located among volcanic strata, at first glance, completely homogeneous porphyritic composition. When making geological sections of such deposits it is necessary to dissect these homogeneous volcanic strata and to distinguish among them reliable marking layers. The success of the correct interpretation of the structure of the ore field or its separate sections depends to a large extent on how correctly deciphered the sequence of formation of various volcanic layers consisting of porphyritic covers or flows.
Ore Altai is one of the major areas of polymetallic deposits of the Soviet Union. Paleozoic volcanogenic rocks play a major role in its geological structure. Most of the industrial deposits are confined to volcanogenic and volcanogenic-sedimentary strata. Regardless of whether the formation of these deposits is related to volcanic activity or volcanogenic rocks are only host to ore deposits, the geological and petrographic study of these rocks is of scientific and practical importance. It makes it possible to clarify the nature and history of volcanism and, consequently, to present the geologic history of the area more fully.
In the southwestern part of the ore Altai, secondary quartzites are widely developed among volcanogenic rocks of the Lower Carboniferous. They compose most of the uplands located to the southwest of the Bukhtarma River valley. The outcrop of some secondary quartzite massifs is measured in several square kilometers. The contours of the massifs in plan are mostly irregular, somewhat elongated in some direction, less often isometric.