Late Pleistocene pericoastal landforms as targets for early coastal site discovery: A case study from Devils Kitchen, Oregon, USA

Identifying Late Pleistocene archaeological sites along the Pacific margin of North America remains difficult outside glaciated areas where emergent paleoshorelines experiencing minimal relative sea level change facilitate early site discovery above sea level. Along much of the Oregon coast and other nonglaciated active-margin settings, postglacial eustatic sea-level rise submerged Late Pleistocene coastal landscapes on the continental shelf, while syntransgressive erosion and Holocene sediment accumulation further reduced the visibility of early terrestrial records. As a result, Late Pleistocene sites are assumed to be absent or poorly preserved in these regions. This study presents a geoarchaeological analysis of the Devils Kitchen site on the southern Oregon coast to evaluate how deposits of the right age (DORA) can persist in inland paleopericoastal settings above modern sea level. Archaeological excavations document a stratified sequence of alluvial and aeolian deposits extending from the terminal Late Pleistocene into the late Holocene. Bayesian chronological modeling of radiocarbon ages indicates that the lowest artifact-bearing deposit has a modeled age range overlapping the Late Pleistocene and early Holocene, while overlying units record continued deposition through the Holocene; the age of the archaeological materials within the lowest deposit remains unresolved. Devils Kitchen is situated on the uplifted southern limb of the Coquille fault, where sustained uplift constrained sedimentary accommodation space, elevated Late Pleistocene land surfaces above marine transgression, and limited the depth of subsequent burial. More broadly, the Devils Kitchen record illustrates how similar tectonogeomorphic settings along nonglaciated margins of the northern Pacific Rim may preserve Late Pleistocene terrestrial deposits above modern sea level, offering a transferable framework for identifying DORA in other active-margin coastal regions.