ROLE OF DUNE LANDSCAPE DEVELOPMENT IN DETERMINING CULTURAL FOCI WITHIN THE TANANA FLATS, CENTRAL ALASKA

Recent archaeological surveys identified 41 intact prehistoric sites buried in an 80 km² loess-mantled, vegetated dune field in the Tanana Flats, central Alaska. Cultural materials appear confined to the crest and upper slopes of the dunes, and include stone tools, debitage, and faunal remains reflective of short-term campsites and hunting activities. This represents one of the densest clusters of archaeological sites known in sub-arctic Alaska. Consequently, an investigation of the dune chronology and morphology was requisite to understanding the context of cultural use of the dunes. Dunes are generally oriented SE-NW (~120-300 degrees) and vary in form (parabolic, linear, ovate, and compound forms of each), with loess “lobes” flanking the east and western sides of larger dunes. Given difficult ground accessibility, dunes were reached via helicopter, and samples for luminescence dating and other analyses were collected via hand bucket auguring on the dune crests and, in some instances, the upper slopes. Dune stratigraphy is generally uniform and consists of eolian silts (loess), ranging from 30 to 350 cm thick, overlying > 7 m of thinly bedded eolian sands. Archaeological remains were recovered throughout the stratigraphic sequence from just beneath the root mat to the upper portions of the eolian sands, typically at 1 – 1.5 m beneath surface. Samples for dating were collected at ~2 m depth to avoid effects of near-surface cryo- and bioturbation and at-depth, near or within the permafrost contact (< 8 m). Infrared stimulated luminescence (IRSL) dating of feldspars was conducted at the University of Nebraska Luminescence and Geochronology Laboratory using a newly developed protocol, which minimizes the luminescence signal fade common to samples at this latitude. Ages from crest samples indicate that the bulk of the dune forms developed ~15-11 ka, with slope ages being somewhat younger, presumably due to post-formational modification. AMS ¹⁴C ages determined from charcoal recovered at three sites agree with the IRSL ages and expand the numerical age database. Stratigraphic position, radiocarbon and IRSL dating indicate nearly continuous use of the dune field by prehistoric hunter-gatherers beginning in the terminal Pleistocene Paleoindian era and continuing through the proto-historic Athabaskan period.