We just published former M.S. student Nick Cunetta's thesis research in GSA Bulletin. For his project, Nick combined field mapping with garnet geochronology to constrain the timing of subduction initiation in the Easton metamorphic suite of the Northwest Cascades. The results document an older history of metamorphism (203 Ma), extend the timing of subduction into the Jurassic (183 Ma), and support models that advocate for long-lived subduction along the western margin of North America.

Cunetta, N.S., Mulcahy, S.R., Schermer, E.R., and Smit, M.A., 2025, Early Jurassic subduction initiation recorded in the Easton metamorphic suite, Northwest Cascades (Washington, USA): GSA Bulletin, doi:10.1130/B38167.1.

The funding for this work was provided by the NSF EAR Division of Earth Sciences Grant # 1550110, the Mazamas, and Ned Brown Endowed Fellowship.