FIRST K-AR DATES AND SR ISOTOPIC COMPOSITION OF BASANITE FROM THE EXPLOSION PIPES OF THE CHULYM-YENISEY BASIN

Abstract

The basanite explosion pipes in the area of the Kop'yevo uplift in the Chulym-Yenisey basin (CYB) are widely known because they contain xenoliths of peridotite, pyroxenite and megacrysts of other minerals and others). However, the age of these diatremes has not yet been reliably established. Tentatively, they are dated as Permian to Triassic, the reason for dating being that these bodies are not found in the Jurassic deposits of the basin, which are, however, of limited extent. This paper reports on the first K-Ar age determinations and 87Sr/86 ratios in the basanite of the explosion pipes, data which should be very useful in petrogenetic analysis.