Paleogeotectonic position of the Kyzyk Chadr porphyry copper ore field, Republic of Tyva

Regional-scale localization conditions of the Kyzyk-Chadr molybdenum-copper porphyry ore field in the southern folded frame of the Siberian Platform are considered. The porphyry mineralization of the field formed at the Salairian (Early Caledonian) phase of development of the Altai-Sayan segment of the Central Asian Orogenic Belt (CAOB), in connection with small intrusions of the gabbro-diorite-granodioritegranite Kyzykchadr Complex (Є2–3). The formation of the ore-bearing complex was associated with an accretionalcollisional magmatic belt superimposed on a Vendian–Early Cambrian volcanic-sedimentary island-arc substrate. The complex is only known within the local Ozhu uplifted block with a “batholitic” massif of the gabbrotonalite-plagiogranite Tannu-Ola Complex (Є2), but it is suggested that there could existed some analogous accretional-collisional Cambrian intrusions productive for Mo-Cu porphyry mineralization in some other areas, that were later overlapped by Ordovician–Silurian and Early Devonian volcanosedimentary deposits or broken by intrusive massifs of the Caledonian collisional volcano-plutonic belt. The rocks of the Salairian and Caledonian magmatic belts were deformed during subsequent geotectonic stages, primarily the Late Paleozoic collision, and overlain by younger sedimentary deposits. The position of economic-grade Mo and Mo-Cu porphyry deposits in the southern Altai-Sayan segment of the CAOB is assumed to be confined to areas of spatial superposition (overlapping) of magmatic belts of the three geotectonic stages: 1) island-arc volcanic belts (V–Є1), 2) “batholithic” intrusions and small intrusions of the magmatic belt of the accretional-collisional stage (Є2–3), 3) the collisional volcano-plutonic belt (O–D1).