Paper No. 3
Presentation Time: 8:50 AM


CAJIGAS, Rachel, Geosciences, University of Arizona, Tucson, AZ 85719,

Soil micromorphology is the practice of analyzing soil or sediment and its components in an undisturbed context with a petrographic microscope. This method was developed more than 80 years ago by soil scientists interested in micropedology. Archaeologists have been using this method in recent decades to determine site formation processes and answer anthropologically relevant questions regarding site construction, intensity of use, deposit type, and distribution and characteristics of activity areas.

This paper presents data from a preliminary micromorphology study of archaeological deposits from St. Catherines Island, a barrier island in coastal Georgia. Many of these archaeological deposits are associated with Foxworth fine sands, which are sandy, marine or aeolian, sediments in the southeastern Coastal Plain. These sites are often located in pine forests with extremely acidic soil conditions that inhibit the preservation of organic and archaeological material. Specifically, I present data on samples collected from the Mission Santa Catalina de Guale pueblo. This site, a 17th century Spanish mission, includes several native habitation structures that were excavated by archaeologists in the early 1990s. These structures were likely constructed of wood and other organic materials and do not preserve well. During excavation blocks of soil were impregnated with resin and styrene for future micromorphology analysis. These samples were collected from inside and outside of the pueblo structures, near archaeological features of indeterminate origin, and in areas of low and high electrical resistance. Twenty years later, they were thin sectioned for analysis.

The acidic soils present a preservation issue visible at the microscopic scale; most samples exhibited little to no cultural materials. While these preservation issues affect our ability to recover materials and detect microfeatures and site-wide soil variations in thin section, future micromorphology analysis at this site will incorporate a sampling strategy focusing on collecting samples in areas with visible color changes or stratigraphic contacts. Sampling in specific features of interest such as postholes, concentrations of charcoal, or middens, may have greater chances of preservation of anthropogenic materials at the microscopic level.