U – PB SHRIMP DATING OF ZIRCONS FROM THE ORE-BEARING KHARAELAKH INTRUSION (TALNAKH DISTRICT, RUSSIA)

Abstract

World-class platinum-group-element (PGE)-Cu–Ni Oktyabr’skoe deposit closely linked to the Kharaelakh ultramafic–mafic intrusion is located in the northwestern corner of the Siberian Craton, Russia. In spite of its significant metallogenic potential, no age constraints for the rocks of the Kharaelakh intrusion are available. Consequently, duration of the ore concentration process responsible to form an economic deposit have never been evaluated quantitatively. This report presents the first results of uranium–lead dating of 19 grains of zircon, which were extracted using ppm-mineralogy technique (NATI Research JSC, St. Petersburg, Russia) from drill core samples of the Kharaelakh intrusion. Rocks investigated include olivine-containing gabbro, olivine gabbro, melanotroctolite and plagioolivinite. Isotope geochemical data (24 analyses) were determined with secondary ion mass spectrometer SHRIMP-II at VSEGEI.