LAST CANYON CAVE: A WINDOW INTO THE LATE PLEISTOCENE ENVIRONMENT OF THE BIGHORN BASIN

Although the exact nature and timing of the first human migrations into North America are still hotly contested subjects among archaeologists, in the geologic timeframe the earliest evidence for a human presence in North America fits occurs during the Late Pleistocene. When discussing this distant point in the past, a very different world is conjured within the mind of the modern individual. The average person might imagine a chilly landscape dominated by ice and populated with megafauna which now appear fantastic and even whimsical by contemporary sensibilities. The First Americans entered a continent with a drastically different ecosystem than what is observed today, and this ancient environmental context certainly influenced their strategy for survival. But how does one come to know the intimate details of an environment that disappeared thousands of years ago? While ice and lake sediment cores have played an important role in the ongoing discussion concerning paleoclimates, cave and rockshelter sediments provide their own distinctive window into the variation in Late Pleistocene environments. One such rockshelter is Last Canyon Cave, located in the Pryor Mountains in southern Montana. This rockshelter possesses a lengthy aeolian sedimentary record beginning approximately 90,000 years ago. In addition, Last Canyon Cave possess the remarkable status of being located immediately south of the Laurentide ice sheet at its furthest extent, and in close proximity to the Alberta ice-free corridor. Previous projects at Last Canyon Cave have included ¹⁴C dating, AMS dating, pollen analysis, and coprolite analysis. The current research aims to add an OSL chronology and grain-size analysis to the existing data. The resulting synthesis of these studies will provide a robust and multi-faceted image of the world that greeted the First Americans, particularly those people in and around the Bighorn Basin, showing the environmental conditions and fluctuations that might have inspired their strategies for survival.