Abstract

Plate tectonic theory implies that orogeny at convergent margins results from several processes, including subduction of oceanic crust, subduction of aseismic ridges, accretion of terranes, and continental collision. Each of these processes involves the consumption of an oceanic tract, and each has its own characteristic style of tectonothermal activity. An additional, potentially important, orogenic process has been largely overlooked. Oceanic regions contain chains of volcanic islands formed at hotspots, which are generally considered to reflect the sites of rising plumes. In a hotspot reference frame, where active continental margins advance and override a plume, the plume's buoyant swell may profoundly change the tectonothermal expression of subduction and hence orogenic processes at the continental margin. The Late Cretaceous–Tertiary evolution of the western United States may be an example of this process, which has been overlooked in the development of orogenic paradigms.

First Page Preview

First page PDF preview
You do not currently have access to this article.