Built on a Bluff: Investigating the Geology of PA’s Riverbanks around Fort Hunter

Ever wonder what exactly a “bluff” is? Why was Fort Hunter located where it was? Geologists have been arguing about bluffs for decades and there are a number of hypotheses proposed about how, why, and when they formed. The Susquehanna River and its tributaries including the Juniata River, not only have a number of active “bluffs” along their modern river courses, but there are relict bluffs or terraces identifiable in the morphology of hillsides above them. In addition, the types and textures of sediments that compose these bluffs often reveal important clues that indicate changes in river flows through time as well as climate. This presentation will explore the fluvial/river terraces of the Fort Hunter/Susquehanna region and address some questions about how these features may have formed geologically and what they may indicate about changes in climate in PA during the recent geologic past.