Hilton, M.R., 2002, Evaluating site formation processes at a higher resolution: An archaeological case study in Alaska using micromorphology and experimental techniques: University of California, Los Angeles, Ph.D. dissertation, 381 p., illust. (some color), color maps.
The polygenetic origins of archaeological sediments create formidable interpretive challenges. Cultural and natural mechanisms operate in tandem to form and transform the archaeological record. While natural formation processes can be complicated in their own right, anthropogenic agents substantially increase the level of ambiguity in interpreting these sediments. In this thesis I cultivate methods first developed by practitioners of the earth sciences to provide insight into formation concepts that otherwise prove elusive. Fieldwork was conducted in coastal zones of southwestern Alaska over a period of four years. The region is characterized by a dynamic natural and cultural history, and the location provides an ideal setting for a study of this nature. Archaeologists regularly cite frost-related mechanisms (cryoturbation) as potential disturbance agents. Actual field data demonstrating the phenomenon, however, are few. In 1999, I established a long-term experiment designed to measure frost-induced displacement of the archaeological record. Objects buried in experimental plots demonstrated little movement after the first year. Objects positioned in one surface plot, configured to minimize the effects of all mechanisms except cryoturbation, moved an average of 4.7 cm during the same period. Objects in a second surface plot, which lacked restraints on wind and other variables, shifted an average of 18 cm, rendering their original arrangement unintelligible. Extrapolated over periods of decades or centuries, the data show that spatial patterning in the archaeological record is subject to substantial postdepositional reworking by frost, wind, and biological agents. I use thin-section micromorphology to assess whether a 6000 year-old living surface at the Mink Island site on Katmai National Park was abandoned due to a volcanic eruption. I also show that thin, dark lenses visible in lithostratigraphic sequences at the site represent the decomposing remains of vegetal fiber rather than charcoal. I further demonstrate that the microfabric of living surfaces at this coastal Alaska site does not resemble the composition of living surfaces identified elsewhere. The differentiation of floor deposits in this sociocultural and environmental context is more complex than in regions where plaster floors were common. Thin-section micromorphology illuminates site formation processes at a resolution unachievable using standard excavation techniques.
Theses and Dissertations