Submarine fan deposystems and tectonics of a late Cretaceous forearc basin along an accretionary convergent plate boundary, Maccoll Ridge Formation, Wrangell Mountains, Alaska

摘要

Analysis of Upper cretaceous sedimentary andvolcanic strata in the Wrangell Mountains of south-centeal Alaskaprovides an opportunity to study the tectonics, depositionalsystems, and provenance of a forearc basin that developed alomgan accretionary onvergent plate boundary. New data from the 1150m thick Maccoll Ridge formation indicate that deposition occurredduring the Campanian on a coarse-grained submarine fan that wasderived from an uplifted allochthonous terrane exposed in thehanging wall of a fault system that separated the forearc basin fromthe subduction complex. New age controls include palynofloraindicative of a late middle to late Campanian age, and compatibleradiometric age determinations of volcanic vitric-crystal tuffs nearthe top of the formation which have