Granitoid Magmatism of the Joint Area between the Severnyi and Glavnyi Batholith Belts of the Verkhoyan–Kolyma Fold Area

Abstract

New U–Th–Pb (SIMS)–geochronological, petro-geochemical, and Sr–Nd isotopic data for granitoids of three plutonic complexes (Sakhani, Omchikanda, and Arga–Emneken), located in the joint area of the two large batholih belts of the Verkhoyan–Kolyma fold area, Glavnyi and Severnyi, are presented. The Valanginian–Hauterivian age of the granitoids of all three complexes is established. The similarity of the granites and leucogranites of the Omchikanda and Sakhani complexes to the I–S-type granites and the similarity of the Arga–Emneken granitoids to the I-type granites are shown. The petro-geochemical peculiarities of the granitoid composition indicate a metasedimentary source for the granites and leucogranites of the Omchikanda and Sakhani complexes and a metamagmatic (amphibolitic) source for granitoids of the Arga–Emneken Complex. Sr–Nd isotopic data show that the granitoids were melted from different crustal sources, in which there are various proportions of mature material of the continental crust. The totality of geological and newly obtained geochronological, petro-geochemical, and isotopic data allow us to suppose a collisional setting of their formation in the terminal Valanginian–Hauterivian stage of collision between the Kolyma–Omolon microcontinent and the Siberian continent.