EVIDENCE FOR MINOR POST-DEPOSITIONAL DISPLACEMENT OF THE METHOW BASIN, NORTHERN WASHINGTON: DETAILED PROVENANCE ANALYSIS OF THE HARTS PASS FORMATION
Although a unique source area cannot be unequivocally determined, the southern Canadian Cordillera provides the best match for these provenance results, given the close correlation in age and available epsilon Hf values between Jurassic and Cretaceous detrital zircon in the Harts Pass and plutons found in southern Canadian Cordillera. Other possible source regions include a combination of the southern Canadian Cordillera, Klamath Mountains, and Blue Mountains, or a combination of the Peninsular Range and Sonoran plutons in Mexico. Well-documented west-directed paleocurrent indicators in the Harts Pass Formation would require the basin to be west of a Klamath Mountains source, putting it a significant distance removed from additional sources in the southern Canadian Cordillera and the Blue Mountains. If the Harts Pass provenance included the Peninsular Range, then it should contain more volcanic lithic grains similar to the Early Cretaceous Alisitos Formation that was shed off the active volcanic arc of the Peninsular Range during the Early Cretaceous. Therefore, provenance results from the Harts Pass Formation suggest that the Methow Basin has not undergone a significant amount of post-depositional translation, and that the most likely sources for the Harts Pass are in the southern Canadian Cordillera, perhaps in combination with the Blue Mountains.