Tectonic implications of a late Paleozoic volcanic arc in the Talkeetna Mountains, south-central Alaska

Reconnaissance studies in the Talkeetna Mountains of south-central Alaska disclosed an Early Permian volcanogenic sequence several thousand metres thick. These rocks are interpreted to represent a volcanic arc system that was accreted to the North American plate in late Mesozoic (probably Cretaceous) time. The northeasterly trend of the volcanic arc system and the parallel structural grain of the Talkeetna Mountains are part of the structural bend of southern Alaska commonly considered to be the result of oroclinal bending, which may instead reflect the shape of the late Mesozoic continental North American plate. The western part of the Denali fault system may be part of a wide, complex zone of high- and low-angle thrust faults rather than the prolongation of an arcuate strike-slip fault system.