Home – Home – Jornals – Russian Geology and Geophysics 2018 number Неопубликованное

The article presents the results of geochronological, geochemical and isotopic studies of intrusive complexes in the central and southern parts of Rudny Altai, which until recently have been practically uncharacterized using modern research methods. The results of U-Pb dating of zircon grains from igneous rocks (26 determinations) made it possible to establish 4 stages of endogenous activity: 1) Late Devonian (~ 370–360 Ma); 2) the end of the Early Carboniferous (~ 330–320 Ma); 3) Middle–Late Carboniferous (~ 315–305 Ma); 4) Early Permian (300–286 Ma). During each stage, both mafic and granitoid magmatism was manifested, which indicates the active development of mantle-crust interaction processes. An examination of the geochemical characteristics of the studied rocks allowed us to draw conclusions about the sources of magmas and the conditions of their melting, while comparison with geological and geochronological data from neighboring regions allowed us to determine the most likely geodynamic regimes for the manifestation of intrusive magmatism in the region. In the Late Devonian, magmatism occurred in a subduction setting on the active margin of the Siberian continent. At the end of the Early Carboniferous, magmatism was associated with the onset of orogenic processes during the formation of the Zaisan folded system orogenic structure. In the Middle to Late Carboniferous, magmatic activity reflects the onset of post-orogenic extension. Early Permian magmatism is due to a combination of post-orogenic extension and the activity of the Tarim large igneous province, formed as a result of the impact of the mantle plume of the same name on the lithosphere. Special attention is given to metallogenic aspects, and suggestions are made regarding the absence of ore deposits associated with intrusive magmatism in the region..