Eruptive history of Middle Sister, Oregon Cascades, USA-Product of a late Pleistocene eruptive episode

New mapping, geochemistry, and argon geochronology illuminate a brief, remarkably silicic episode set in a mafic segment of the Cascade arc. Middle Sister was constructed during a 35-k.y. episode in the late Pleistocene from mafic, intermediate, and silicic eruptions adjacent to the primarily rhyolitic South Sister. Eruptions in the Three Sisters volcanic cluster prior to 50 ka were exclusively mafic (