Russian Journal of Earth Sciences
Vol. 3, No. 1, March 2001

New K-Ar Ages for Basalts from Franz Josef Land

A. F. Grachev, M. M. Arakelyantz, V. A. Lebedev, E. E Musatov, and N. M. Stolbov

Abstract

New K-Ar age determinations on basalt samples from three drillholes and outcrops on Franz Josef Land suggest that flood volcanism throughout the archipelago fits in a very narrow age interval (116 pm 5 Ma). For 95% of the samples we studied, age scatter is within analytical uncertainty. New data on basaltic bulk-rock, trace element, and REE compositions point to mantle plume affinity for the Early Cretaceous magmatism on Franz Josef Land, which preceded the onset of seafloor spreading in the Canada Basin.