RUBIDIUM-STRONTIUM AGE AND GENESIS OF THE KIYA ALKALIC PULTON, YENISEY RIDGE

Abstract

The Kiya alkalic pluton lies on the western part of the Yenisey Ridge at the center of the Chernorechensk graben. It is confined to a zone of intersecting deep faults with northwest and northeast strikes. For isotopic dating purposes, we sampled the main rock types of the pluton after predetermining concentrations of K, Na, Rb, Sr and Ba in a larger suite of the same rock types. The isotopic analyses of the samples were done with a MI-1201B mass spectrometer. Our rubidium-strontium dates confirm the view as to the Permian age of the Kiya alkalic pluton, as determined by potassium-argon and lead-isotope methods, and raise doubts concerning existing theories on the Devonian age of the Kiya complex.