AN INTEGRATED AND ARCHAEOLOGICALLY SCALED SOIL GEOMORPHIC AND SOIL STRATIGRAPHIC APPROACH TO ARCHAEOLOGICAL RESEARCH IN ALLUVIAL ENVIRONMENTS (Invited Presentation)

Prehistoric cultural deposits are common in both surface and buried contexts in river valleys as rich and varied valley resources were widely utilized in the past. An increasing number of models of valley landscape evolution demonstrate spatial and temporal patterning, and therefore predictability, in the age and origin of alluvial deposits and valley environments on landscape and landform scales. It follows that there also ought to be spatial patterning and predictability in the cultural deposits following valley resource utilization in those environments. Success of this latter modeling at the finer scales depends on recognition that floodplains themselves are comprised of a range of depositional environments, recognition of which calls for an integrated, appropriately-scaled approach in which soils play an important role.

Among key underlying concepts to such an approach are a dynamic model of soil evolution; integrated soil stratigraphy and geomorphology; and, alluvial veneers and their paleoenvironmental significance.

Integrated techniques of the approach are geared to a scale in line with prehistoric land use. Elemental are LiDAR-based digital elevation models and topography; graphic sediment soil logs of appropriate scale that acknowledge that there is more to fine grain sediment than ‘mud’; Munsell half-chip dark soil colors that reveal differentiation of stacked and welded upper sola; and, examination of cores in both moist and dry states.

The matching of scale and integration of these techniques can yield in depth results. Drawn from work in progress in the Knob Creek Bottom of the Ohio River Valley downstream of New Albany, Indiana, example results show: 1. A previously mapped mollisol demonstrated to be a soil complex that includes three buried soils; 2. Subtle geomorphic and hill slope segment differences in the natural levee environment that have soil-stratigraphic and subtle soil-morphologic consequences; and, among others, 3. A previously undifferentiated fine grain low terrace sediment assemblage that is divisible into at least six lithofacies with prehistoric settlement, activity, discovery and other archaeological implications.