The generation of high Sr/Y plutons following Late Jurassic arc-arc collision, Blue Mountains province, NE Oregon

► This study examines post-tectonic, high Sr/Y plutons in the Blue Mountains province, NE Oregon. ► High Sr/Y magmatism occurred over a brief interval and followed low Sr/Y magmatism and contraction. ► We attribute high Sr/Y magmatism to collisional thickening of island arc crust. ► Similar, post-tectonic high Sr/Y plutons occur throughout the western North American Cordillera. ► These plutons signify episodic generation of high Sr/Y magmas following collisional tectonism.