The duration of formation of mobile zones of Caledonides, Hercynides, Kimmerides and Alpides is on average the same and is 160+/-15 Ma. The ratio of the time of formation of orogenic structures to geosynclinal structures proper in the mobile zones hosting large stratified deposits of lead and zinc is 10 %, volcanogenic copper-zinc deposits - 33 %, and rare-metal (Sn, W, Mo, Ai) - 75 %. This circumstance is connected, apparently, with the degree of warming of the Earth's crust and its processing by mantle fluid flows.
Application of decryptometric survey for disassembling bearing rare-metal mineralization of granite massif of East Transbaikalia gave positive results. Two types of decryptograms are observed. The first one, with a distinct maximum in the temperature range of 300-550 °С, is characteristic for samples from steaming halos of unpromising Taptanai and Sakhanai massifs. The second, with distinct maxima at temperatures of 120; 250 and 400-600 °С, is characteristic of samples from the halos of the Dedonogorsky and Etykinsky massifs, which are associated with industrial rare-metal mineralization.
In connection with the search for blind ore bodies and the evaluation of mineralization at depth, the study of vertical and horizontal zonation has recently received increasing attention. In this regard, the area of the central part of the Miao-Chan Ridge belongs to the region of Mesocenozoic folding and is composed of terrigenous formations of Jurassic age and Cretaceous effusives. Sand-shale strata of the Middle and Upper Jurassic are crushed into northeastern strike-slip folds and unconformably overlain by Cretaceous effusives of acidic and medium composition. The Cretaceous sediments are also folded into gentle folds. Discordant small intrusions of Upper Cretaceous age are widely developed in the area, more often with a characteristic hybrid composition - gabbro, gabbro-monzonites, diorites, diorite-porphyrites. Magmatic activity in the area ended with the introduction of a series of dykes of lamprophyre composition.
According to the nature of changes in the relations of productivity of the main ore elements of sulfide-cassiterite deposits of the Miao-Chan Ridge from the center to the upper edge of ore bodies and the degree of remoteness of these bodies from small hybrid intrusions, with which tin mineralization is closely associated, it is possible to estimate the cut-off levels of ore bodies.
