Siluro-Devonian Sedimentation on Somerset and Cornwallis Islands, Arctic Canada

Abstract

ABSTRACT Stratigraphic sequences of Upper Silurian - Lower Devonian cratonic sediments on Somerset Island and near the craton margin on Cornwallis Island to the north show strong lithological and faunal similarity. The predominantly intertidal Cape Storm Formation is overlain by subtidal rocks of the Read Bay Formation (Member A) on both islands; a regressive succession of intertidal and fluvial clastics is common to the upper parts of both sections. However, the thick subtidal and intertidal sequence of Members B and C in the middle of the section on Cornwallis Island has no lithological equivalent on Somerset Island. Members B and C appear instead to be equivalent in age to the continental sediments on Somerset Island. Paleocurrents indicate that the Boothia Uplift was the source of the coarse clastics on both islands. Extension of the locus of uplift led to a northward advance of continental sedimentation with time.