Re-evaluating terminal Pleistocene and Early Holocene settlement patterns with Chirp subbottom data from around California’s Northern Channel Islands

ABSTRACT California’s Northern Channel Islands contain an incredible record of terminal Pleistocene and Early Holocene human occupation. Since the hunter-gatherer-fishers who created these sites relied heavily on marine resources, a critical aspect of understanding early settlement patterns is calculating distance to paleoshorelines. This has traditionally been accomplished using sea-level curves and bathymetric models that do not account for sediment deposited offshore after inundation by rising seas. Here, we use high-resolution Chirp subbottom data to re-evaluate distance to paleoshorelines at two terminal Pleistocene and Early Holocene site clusters on the Northern Channel Islands and identify significant differences between the methods. Our results suggest that Chirp subbottom surveys offer more accurate reconstructions of ancient shorelines than bathymetric modelling and can produce more accurate reconstructions of ancient settlement patterns of terminal Pleistocene and Early Holocene peoples along coastal and island environments around the world.