Spatial Interpretation of Site Formation Processes Using Soil Stratigraphic Relationships: An Example from North-Central Nevada, U.S.A.
The clear determination of soil stratigraphic relationships is critical to understanding artifact contexts. This perspective is best achieved by the precise, 3-dimensional, spatial delineation of soil/sediment bodies across the site, including compilation of a master soil stratigraphic sequence that reconciles both sedimentary and pedologic events and features. This study investigates these contexts at a site occupying alluvial terrace surfaces at the confluence of three ephemeral stream channels. Geoarchaeological investigation reveals 26 stratigraphic units, comprised of alluvial sediments, aeolian silts, volcanic ash, the horizons of five paleosols, and a recent surface soil. In addition to detailed stratigraphic descriptions, the construction of an isopach map reveals the complex character of the site's formation processes, and the resultant archaeological setting. The combination of terrace surfaces and at least three major depositional events, alternating with four individual soil episodes, allows for several artifact contexts to exist.