An Archaeological and Geomorphological Survey in the Central Des Moines River Valley, Iowa

The effects of temporal and spatial patterns of Holocene erosion and alluviation on the archaeological record of the Central and Eastern Great Plains, U.S.A.

“…Tributaries are steep and short with few exceptions. Geologic and archaeological studies in the Saylorville Lake area provide a detailed picture of the Holocene fluvial activity and geologic influences on the archaeological record of the central Des Moines River Valley (Bettis and Benn, 1984;Benn and Bettis, 1985;Bettis and Hoyer, 1986;Bettis, 1992). Van Nest and and Krieg (1997) The central Des Moines River and Skunk River valleys originated as major subglacial drainage tunnels of the wasting DML.…”

“…An understanding of regional stratigraphic patterns is crucial to the interpretation of the archaeological record of valley landscapes (Bettis and Benn, 1984;Johnson and Martin, 1987;Mandel, 1995;Bettis and Hajic, 1995). Patterns of erosion and deposition strongly influence the preservation and visibility of archaeological deposits.…”

Archaeological Survey of the Proposed Johnston Trails Project in the Downstream Corridor, Saylorville Lake, Polk County, Iowa. Phase 1

“…In particular, at least one or several high energy depositional episodes deposited the gravel forming the High Terrace upon which much of the proposed Traverse A portion of the project area lies. The High Terrace appears to be the result of a complex deposition and erosion sequence, and it seems probable, based upon site reconnaissance and research that a generalized description of the High Terrace should include a Camp Creek member overlying a Corrington or Gunder Member alluvial fan that has been truncated by fluvial activity where it meets the current Des Moines river channel (Benn and Bettis 1981;Bettis and Benn 1984;Art Bettis, personal communication 1993).…”

“…The Downstream Corridor encompasses approximately 1,210 ha (2,990 acres) of floodplain along the Des Moines River between the Saylorville Dam and the Sixth Avenue bridge in the City of Des Moines (Benn and Bettis 1981:ii;Ron Pulcher, personal communication 1993). The cultural and environmental history of this area has been described in detail by Benn and Bettis (1981) and Bettis and Benn (1984). The Downstream Corridor involves a complex series of geological events most of which occurred at the end of the Wisconsinan when glacial outwash and ice wasting dramatically effected the landscape in the Des Moines River Valley.…”

Phase II Archaeological Testing of the Helmkamp Site (11MS2025) in Support of the Proposed Grassy Lake Pump Station and Associated Ditch Work, Wood River Drainage and Levee District, Madison County, Illinois

“…Such a perspective on the location of human occupation sites allows the investigator to create predictive models of archeological site occurrence and patterned distribution within a given area relative to the existing landforms within that area (cf. Bettis et al 1996;Bettis and Benn 1984;Hajic 1993;Saucier 1994). Specifically, this approach is useful for recognizing post-settlement alluvium (PSA), made land, plowzones (Ap horizon), and other disturbances that may have modified the landforms under investigation as well as for realizing the potential for deeply buried sites.…”