Upper Paleozoic stratigraphic history and provenance of the Farewell terrane, SW Alaska

The Farewell terrane, in southwest Alaska, is predominantly located in the western Alaska Range, but crops out as far north as the Kuskokwim Mountains and represents one of the largest exotic terranes in the North American Cordillera. Exposed both north and south of the Denali fault, the Farewell terrane contains three somewhat distinct stratigraphic successions: I) Neoproterozoic--Devonian carbonate rocks of the Nixon Fork subterrane, 2) Cambrian--Devonian carbonate and siliciclastic strata of the Dillinger subterrane, and 3) Devonian--Jurassic(?) siliciclastic strata of the Mystic subterrane. This investigation aims to constrain the upper Paleozoic tectonic evolution of the Farewell terrane through sedimentologic interpretations and measured stratigraphy as well as by utilizing combined provenance techniques of sandstone modal compositions and U--Pb detrital zircon geochronology.;Measured stratigraphy and sedimentologic analyses of upper Paleozoic (Mississippian--Permian) siliciclastic strata from the Mystic subterrane suggest a submarine basin-floor turbidite fan depositional environment. Modal composition trends reveal pervasive occurrences of lithic volcanic and sedimentary grains reflecting contributions from a magmatic arc to a recycled orogen source. U-Pb detrital zircon age peaks from the newly defined Mystic Pass formation reveals four trends in age spectra: 2000--1800 Ma, 465--405 Ma, 365--315 Ma, and 305--290 Ma. These trends correlate with both Siberian and North American magmatic source areas.