LATE QUATERNARY STRATIGRAPHIC SETTING OF THE GENEVIEVE LYKES DUNCAN SITE, 02 RANCH, BREWSTER COUNTY, TEXAS

The Genevieve Lykes Duncan site lies buried in alluvium near the confluence of Terlingua Creek and a major tributary, close to the point that Terlingua Creek passes from Paradise Valley into Green Valley. Work has focused on three localities within the gully that exposes the Paleoindian age occupation, and these are named Mask, Broadway, and Terlingua from east to west, respectively. Geological investigations at the site to date have assessed the stratigraphy at two different scales. At the macro-scale, the gully that exposes the Paleoindian and Early Archaic age occupations has revealed three allostratigraphic or unconformity bounded depositional units that span the entire Holocene and that represent three distinct depositional periods separated by phases of erosion. Deposition of the oldest unit began before 13,000 cal BP (before present) and continued until sometime around or shortly before 5700 cal BP. A period of erosion ensued and beveled the margin of the first deposit. When sedimentation of the middle unit began is imprecisely known, but a hearth at the Terlingua locality about 90 cm below the surface indicates that deposition of this unit was nearly complete by about 3400 cal BP. The youngest depositional unit at the site caps the sequence and is unaltered by soil development and is thought to be of modern age and remains undated at this time.