Evolution of the Long-lived Yellowstone Hotspot from Offshore California at 56 Ma to its Current Position at Yellowstone National Park

Vic Camp

Dr. Vic Camp
San Diego State University – Department of Geological Sciences

Wednesday, February 24, 2021
watch Dr. Camp’s talk

Field mapping together with an interdisciplinary dataset of geochemical, geophysical, and geochronological data support the idea that the Yellowstone hotspot is fed by a long-lived mantle plume with a surface history that extends to at least 56 Ma.  Eocene volcanism above the hotspot began offshore of northwestern California with voluminous submarine eruptions that created the Siletzia oceanic plateau.  Siletzia accreted onto the North American plate from 51-49 Ma. This resulted in repositioning of the Farallon trench west of Siletzia from 48-45 Ma and the initiation of a new subduction regime that generated early eruptions along the southern Cascades volcanic arc.  The hotspot entered the trench and transitioned from the Farallon plate to the North American plate from 42-34 Ma.  The continued eastward migration of the continental hotspot after 30 Ma occurred at the same time that western North America was evolving from a convergent to a transform plate boundary south of the Mendocino triple junction. The interplay between plume-lithosphere interaction and plate-tectonic change as the hotspot migrated across the Cascadia back-arc region will be described more fully in this seminar talk.