Tertiary Basalts of Baffin Island: Field Relations and Tectonic Setting

Abstract

This paper describes the field relations of Tertiary basalts which are preserved as small patches intermittently along the coast for 90 km northwest from Cape Dyer, Baffin Island. The flat-lying, subaerial lavas generally rest directly on the Precambrian basement but in some localities a thin sequence of terrestrial sediments intervenes between the basement and the volcanics. Where the sediments occur, the overlying volcanics tend to be divisible into a lower unit of subaqueous volcanic breccia and an upper sequence of subaerial flows. In age, stratigraphic position and magma-type, these volcanics strongly resemble those of the basalt province of west Greenland. A model is presented for the generation of both provinces in a single volcanic episode, related to the opening of Labrador Sea – Baffin Bay by continental drift.