Abstract

Northwest-plunging Cornwall Arch dominates the structural geometry of Upper Triassic to Upper Cretaceous marine and nonmarine terrigenous clastic rocks on Cornwall and Amund Ringnes Islands. The arch is at least 200 kilometres long, about 70 kilometres wide, and has structural relief of about 4,000 metres; it is asymmetric, with a homoclinal, gently dipping western flank, and a steeper, structurally disrupted eastern flank.

New evidence indicates that the age of the arch is Late Cretaceous or early Tertiary: Maestrichtian strata lie conformably on the Mesozoic succession, but Paleocene - Eocene deposits are discordant with underlying rocks and structures. Local evaporite-cored diapirs may be considerably older than the arch.

The structural style of Cornwall Arch may be accounted for by a tectonic model that relies on crustal fracturing and great vertical uplift as the dynamic mechanism.