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Abstract—: Integrated structural geological, minerogenic, and metallogenic studies with allowance for previous topical surveying, geological mapping and prospecting, and mineral exploration data has revealed that Upper Paleozoic and Early Mesozoic tectonomagmatic structures are widespread in the Selenga ore district. They are associated with the evolution of the transregional Upper Paleozoic Selenga–Vitim rift-related volcanoplutonic belt and the formation of the Early Mesozoic West Transbaikalian region of intraplate magmatism. Late Paleozoic–Mesozoic igneous activity accounts for the bulk of mineable mineral resources in the Selenga ore district concentrated inside and outside the ore clusters (Kunalei, Kizhinga, Cheremshana–Oshurkovo, Tashir, etc.). It is demonstrated that the main mineable metals in the district are molybdenum and beryllium, which determine the minerogenic specificity of the ore district. New compositional characteristics of the Upper Paleozoic and Early Mesozoic intraplate magmatic complexes and the associated mineral deposits (Mo, Be, Ti, quartz, fluorite, and apatite ores), as well as other promising gold, uranium, and REE–Ba–Sr ore occurrences were obtained. The geodynamic settings of their formation and the ages of the main ore-forming processes have been established; the viability of the mining industry in the Selenga ore district and the feasibility of involving its ore potential in the district’s economic modernization program have been assessed.

This paper deals with the geodynamic evolution and some problems of metallogeny of the Central Asian and Mongol-Okhotsk fold belts. It has been established that throughout its history (from Proterozoic to Cenozoic) all known types of geodynamic settings existed. It has been found, that each setting has a strictly specified geodynamic structure, a number of tectonic structures, magmatic and metamorphic complexes and related mineral deposits. Each geodynamic setting has its own well-defined structural-magmatic and metallogenic zonation. Metallogenic analysis performed on the basis of paleogeodynamic reconstructions for short intervals suggests a position of the ancient borders of the litospheric plates. Magmatics and metallogenic activity was found along and around the boundaries of these plates. This analysis also suggests additional criteria for prediction and search for minerals within Transbaikalia and Mongolia.

The Transbaikal orogenic belts are located in southern Siberia, in the Lake Baikal area. They include the Baikal-Patom fold-and-thrust belt, together with the Siberian platform forming the North Asian craton, and a collage of terranes to the south of the belt that were accreted to the craton in Late Riphean and Early to Late Paleozoic times.The delineated terranes are the fragments of Riphean and Paleozoic island arcs, oceanic crust, turbidite basins of the continental slope and its rise, shelves, and fragments of the craton consisting of Archean and Early Proterozoic crystalline rocks. The accretion resulted in the successive build-up of the Siberian continent from north to south, accompanied by large strike-slip displacements caused by the wedge-like shape of the southern protrusion of the North Asian craton, as well as by repeated deformations and high-temperature metamorphism of the previously accreted terranes and adjacent craton margin.

With the help of devised multicycle consecutive transformation (MCT) it is shown that Ca2+-dependent competence can be repeatedly induced in the same population of Escherichia coli cells. The same fraction of cells is induced to competence and transformed during MCT. In contrast to the results on classical transformation with mixed DNA preparations, no double transformants are observed in MCT. The competent cells and transformants are found to be more fragile than nontransformed cells. The latter are represented presumably by the cells that have not absorbed exogenous plasmid DNA. The results suggest that there is strong interference between plasmid DNAs during MCT, and that the presence of exogenous DNA makes the cells more sensitive to the apparently harmful procedure of repeated competence induction.