The first U–Pb isotope age data of island arc and continental–margin magmatism in the central part of the Koryak Highlands and U–Pb age of ore-controlling granitoids of the talyayigin ore field

Resumo

Precision U–Pb (SHRIMP-II) isotope geochronological data, obtained for the first time, make it possible to suggest that sediments of the Neocomian primitive island arc sequence are missed or poorly developed in the South-Western part of the Mainitskii terrane of the Koryak Highlands. However, Late Albian mature island arc tuff and tuffaceous–turbidite formations are common. This enables us to extend the age range of the Mainitskii island arc from the Early Neocomian to the Late Albian and to suggest a two-stage pattern of its development. The isotope-geochronological data obtained for plagiogranite and moderately acid subvolcanics, previously attributed to the Koryak–Western Kamchatka volcanoplutonic belt, indicate that it is possible to combine them into the Middle Miocene postsubduction? polygenic complex. In addition, owing to modern high-precision isotope–geochronological methods, it has become possible to determine the age of gold–sulfide mineralization of the Talyaigin ore field, paragenetically related to the manifestations of the Middle Miocene Vilyuneiveem complex.