Skip to Content

Sediments, Soil and Stratigraphy

stratigraphic profile from Zatopec The objective of the geoarchaeological work (an approach combining principles of geology and archaeology) performed at Zatopec was to determine the integrity and formation processes associated with the site and the contents contained therein. Sediments and soils of the site were examined through a series of four profile exposures spaced across the site. Each profile was illustrated, photographed, and sampled. Samples were collected in five-centimeter increments to provide fine resolution from top to bottom, and were analyzed for particle size, calcium carbonate content, and magnetic susceptibility.

Sediments at Zatopec are not deep. The relatively shallow burial of cultural material on a relatively flat landform adjacent to a confluence of streams would normally tend to favor interpreting the site's matrix as alluvium, or resulting primarily from moving water from the nearby Purgatory Creek. Environments where alluvium has been deposited are often viewed as ideal for the burial, preservation, and stratification of cultural remains. A critical examination of the deposits exposed at Zatopec, however, failed to clearly demonstrate whether the deposits are alluvium or the result of weathering limestone bedrock. Additionally, evidence may also, weakly support the burial of artifacts by a process called pedoturbation. This term refers to the in-place movement of soil due to processes such as expanding and contracting (resulting from wetting and drying), animal burrowing, human activities (like digging pits), root action, and other causes.