GEOARCHAEOLOGICAL INVESTIGATION OF FEATURE PRESERVATION AND VARIABILITY AT DUST CAVE, ALABAMA

Rarely are features preserved at open-air archaeological sites. Cave environments, on the other hand, offer exceptional preservation conditions for this under-represented aspect of material culture. Such is the case at Dust Cave, a Late Paleoindian through Middle Archaic (10,650-3,600 cal. B.C.) archaeological site in northwest Alabama. Using an interdisciplinary approach integrating geochemistry and micromorphology, we develop a typology of feature types, ranging from in situ hearths to charcoal and ash concentrations in secondary context. Elemental analysis of HCl leachates of cave sediments by ICP-AES indicates: 1) anthropogenic sediments differ significantly from geogenic sediments; 2) phosphorus (P) levels serve as a useful indicator of occupation intensity; 3) strontium/calcium (Sr/Ca) and potassium/phosphorus (K/P) ratios help identify anthropogenic materials; 4) calcium (Ca) levels serve as a proxy for feature decalcification and preservation potential; and 5) calcium (Ca), K, and Sr levels highlight diagenetic hydrologic perturbations. Micromorphological samples provide additional information on post-depositional processes that modify features, including bioturbation, sheetwash, and decalcification. This combined knowledge adds significantly to our understanding of activity variation at the site, as well as post-depositional processes that may obscure the archaeological record in karstic environments and therefore lead to inaccurate reconstructions of human activity.