Early Silurian Age of Skarns of the Ichkeulmes Cu–Au Deposit (Northern Kazakhstan): Results of U–Pb (ID-TIMS) Geochronological Studies of Garnet

Garnet crystals are studied in rocks of the Ichkeulmes Cu–Au deposit located at the southwestern contact of the Selety granite pluton of the Krykkuduk complex. The garnet includes polychrome zoned grains and individual evenly colored crystals. The garnet grains often have zonation due to the alternation of the andradite and grossular zones. The U–Pb (ID-TIMS) geochronological studies were conducted for green and brown polychrome and individual garnets and the substantiated Early Silurian (438 ± 1 Ma) age of their crystallization is suggested to be the age of formation of skarns of the Ichkeulmes deposit. The presence of solid-phase inclusions of the aikinite group minerals in garnet, which are paragenetically related to gold mineralization, indicates synchronous formation of the studied garnet and ores.