Stratigraphy of the Faro Peak formation, central Yukon: New field observations of Jurassic synorogenic sedimentation along the Yukon-Tanana–Slide Mountain terrane boundary

The Faro Peak formation is a Lower Jurassic(?) unit assigned to the Yukon-Tanana terrane in the southern Tay River map area (NTS 105K). A two-year project was initiated in 2018 to investigate the Faro Peak formation and constrain its stratigraphy, age, and significance to Cordilleran tectonic evolution. The exposed base of the Faro Peak formation includes argillite and organized to disorganized sandstone units that crop out southwest of the Yukon-Tanana–Slide Mountain terrane boundary near Faro. Lower Faro Peak formation units have mafic-intermediate volcanic provenance and were deposited by concentrated density flows or turbidity currents. The upper Faro Peak formation contains massive, disorganized conglomerate and sandstone units that were sourced from the Yukon-Tanana and Slide Mountain terranes and deposited by non-turbulent debris or density flows. The Faro Peak formation is likely the remnant of a synorogenic basin that formed as a result of Intermontane belt exhumation in central Yukon.