Published In

GSA Today

Document Type


Publication Date



Fault systems -- Oregon, Fault lines (Geology), Volcanology -- Research


The Yellowstone hotspot is recognized as a whole-mantle plume with a history that extends to at least 56 Ma, as recorded by offshore volcanism on the Siletzia oceanic plateau. Siletzia accreted onto the North American plate at 51–49 Ma, followed by repositioning of the Farallon trench west of Siletzia from 48 to 45 Ma. North America overrode the hotspot, and it transitioned from the Farallon plate to the North American plate from 42 to 34 Ma. Since that time, it has been genetically associated with a series of aligned volcanic provinces associated with ageprogressive events that include Oligocene high-K calc-alkaline volcanism in the Oregon backarc region with coeval adakite volcanism localized above the hot plume center; midMiocene bimodal and flood-basalt volcanism of the main-phase Columbia River Basalt Group; coeval collapse of the Nevadaplano associated with onset of Basin and Range extension and minor magmatism; and late Miocene to recent bimodal volcanism along two coeval but antithetical rhyolite migration trends—the Yellowstone–Snake River Plain hotspot track to the ENE and the Oregon High Lava Plains to the WNW.


Copyright (c) 2021 The Authors

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Locate the Document




Persistent Identifier

Included in

Geology Commons