Michael R. Hilton
Ph.D., University of California, Los Angeles, 2002
Research Associate, Cotsen Institute of Archaeology at UCLA
Research Interests: site formation processes, micromorphology, freeze/thaw cycles as transformation agent
Research Area: North Pacific, Alaska Peninsula

The polygenetic origins of soils and sediments encountered in archaeological contexts create difficult interpretive challenges. A complex blend of physical and chemical processes are further complicated by anthropogenic agencies. Collectively, these mechanisms produce considerable ambiguity in the archaeological record.

I advocate in my research a more intensive examination of the processes which form and transform the archaeological record. My objective is to better characterize the natural and cultural processes responsible for site structure. One method I employ toward that goal is micromorphology, the study of undisturbed sediments in thin section. The technique permits examination of sediment structure and fabric at a higher resolution. As a result I can better interpret pre-depositional environments, anthropogenic alterations, and post-depositional disturbances.

(right) I use a polarizing microscope to examine undisturbed archaeological sediments in thin section. Magnified under different light sources, sediment structure and fabric can be examined at a resolution unattainable in the field. Undisturbed resin-impregnated sediments preserve indefinitely ambiguous stratigraphic contexts for repeated reexamination.


Freeze-thaw cycles are regularly cited as potential transformation mechanisms, yet actual field data demonstrating the phenomenon are few. In 1999 I established a long-term experiment on the Alaska Peninsula to monitor surface and subsurface displacement of the archaeological record. After only three winters surface plots in particular, displayed substantial movement. In one plot, configured to minimize the effects of other transformation agents (e.g., wind and surface runoff), individual artifact displacement averaged 7.8 cm. Original artifact arrangement was unintelligible in a second plot which lacked restraints on wind, biological agents and other variables. The results have important implications for the interpretation of spatial patterning in archaeological contexts.


(above) This photograph illustrates a portion of the Katmai National Park and Preserve on the Northern Alaska Peninsula. Pictured in the foreground is the location of a four-year archaeological project sponsored by the National Park Service. In addition to providing the data for my site formation research, this is the location of a long-term experiment I designed to gauge the degree that freeze/thaw cycles can transform the archaeological record. Photo courtesy of the National Park Service.