Abstract
Regional structural doming of Neogene age has affected rocks of the Klamath and Cascade mountains near the California-Oregon border. Evidence for this is seen in (1) subannular outcrop patterns of pre-Cretaceous lithotectonic units, (2) a crude pattern of radially oriented high-angle faults, (3) tilted Jurassic plutons, (4) tilted Cretaceous to Miocene strata, and (5) various geomorphological features. The age of doming is constrained by a major middle Miocene to earliest Pliocene angular unconformity within the Cascade Mountains and uplifted upper Miocene marine beds on the western edge of the Klamath Mountains. Uplift and doming may be the result of shortening in the Cascade fore-arc region or, more speculatively, the recent accretion of subducted material to the North American plate beneath the Klamath Mountains.