Nature Geoscience Highlights Geology Professor's Latest Publication
November 30, 2018
Writer Marc-Andre Gutscher summarized Dr. Gary Axen's latest paper, which appeared
in Nature Geoscience on November 26, 2018. Axen's co-authors are Dr. Jolante van Wijk,
also of NMT, and Dr. Claire Currie of the University of Alberta. Here is an excerpt
of Gutscher's article with links to that article and Axen's publication at the bottom
of this page.
Scraped by flat-slab subduction
During flat subduction, material is scraped off the base of the continental mantle lithosphere, building a migrating keel. This testable mechanism for flat subduction recreates features of the Laramide orogeny.
In most subduction zones, the oceanic plate descends below an overriding continental plate from a deep-sea trench and down into the mantle. The oceanic plate descends at an angle and this slab dip angle generally increases from a few degrees at the trench to 30° or more at depth. In some cases, the slab dip can reach extremes of close to vertical or horizontal. In cases of near horizontal dip, having reached 20° to 30°, the slab dip decreases and the subducting plate proceeds for several-hundred kilometres almost horizontally, sliding along the underside of the overriding plate’s belly.
Writing in Nature Geoscience, Axen et al. present numerical simulations showing that during this horizontal phase, the flat slab scrapes off 20 to 50 km of the overriding continental mantle lithosphere.