A tectonic model of the Early Precambrian evolution of the South Yenisei Range

The periphery of the Siberian craton stores a record of the ancient history of our planet, of which the most important events are consolidation of continental crust, disintegration of continents, and opening of oceans. The southwestern surroundings of the craton include the Early Precambrian blocks of the Yenisei Range (in the center) and the northern blocks of East Sayan composed of fold and thrust belts or marginal basement uplifts. The South Yenisei Range (Angara-Kan block) involves the greatest portion of the metamorphic and igneous complexes of the southwestern craton surroundings. The region underwent a complex tectonic evolution, as evidenced by a close spatial association of various lithological units and high metamorphic grades of rocks. Collisions are the best evident events of the history of the South Yenisei Range, which are responsible for high-grade metamorphism of high-pressure granulite to amphibolite facies, crustal thickening, and large-scale emplacement of the Tarak granitoids. The orogeny gave way to rifting of the thickened crust associated with formation of metamorphic core complexes. As a result, several blocks of high-grade rocks were exposed by crustal extension and brought close to less metamorphic blocks. The removal of pressure was accompanied by magmatic underplating in the lower crust, which induced rheomorphic melting and homogenization of metamorphic complexes with a granite-like lithology and formation of porphyroblastic granitoid plutons.