ARCHEAN AGE OF MIASKITE LAMPROITES FROM THE PANOZERO COMPLEX, KARELIA

Abstract

Ultrapotassic bodies classed with miaskite lamproite were found within the Archean Panozero magmatic complex on the southwestern coast of Lake Segozero, Central Karelia. The tectonic contacts of these bodies with host rocks make it impossible to determine their geological age and relations with the rocks of the Panozero Complex. The ages of previously studied ultrapotassic rocks are no older than Proterozoic. Compositionally close rocks were described only in the Udoks layered intrusion. Up to now, only nepheline syenites and carbonatites were known among Archean alkaline rocks. In this context, the isotope dating of the ultrapotassic rocks of the Panozero Complex is of special interest, because the data obtained may expand the age interval of potassic alkaline magmatism in the Early Precambrian.