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.

Abstract

Patterns of erosion and deposition act as a filter that strongly influences the disposition of the archaeological record of the Central and Eastern Plains of the North American Midcontinent. Detailed studies of alluvial valley stratigraphy in four drainage basins in the region reveal temporal and spatial patterns of fluvial system behavior that control the preservation and visibility of past human activity. These basins are located on a 600‐km‐long longitudinal gradient extending from semiarid southwestern Kansas to moist‐subhumid central Iowa. Despite significant environmental variability along this transect, basin‐wide patterns of Holocene erosion and deposition are similar across the study area. From ca. 11,000 to 8000 yr B.P., aggradation, punctuated by slow alluviation and/or stability around 10,000 yr B.P., was the dominant process in large and some small valleys. The early and middle Holocene (ca. 8000–5000 yr B.P.) was a period of net erosion and sediment movement in small valleys, sediment storage in large valleys, and episodic aggradation on alluvial fans. During the late Holocene (post‐5000 yr B.P.), alluvial fans stabilized, small valleys became zones of net sediment storage, and aggradation slowed in large valleys. Basin‐wide aggradation followed by entrenchment and channel migration characterizes fluvial activity during the Historic period. Consideration of the effects of these temporal and spatial patterns of Holocene erosion and alluviation on the archaeological record is crucial for developing efficient cultural resource sampling strategies and for accurately interpreting the archaeological record. © 2002 John Wiley & Sons, Inc.

Biomantle formation and artifact translocation in upland sandy soils: An example from the Holly Springs National Forest, north‐central Mississippi, U.S.A.

“…In recent years, biases introduced by geomorphic processes into archaeological survey results have been increasingly recognized (e.g., Mandel, 1995;Stafford, 1995;Tankersly et al, 1996;Waters and Kuehn, 1996;Wilkinson, 2000;Bettis and Mandel, 2002;Stafford and Creasman, 2002). Upland landforms in the Southeast and elsewhere are often considered to be geomorphologically "stable" except for Historicperiod erosion.…”

A geomorphic framework for understanding the surface archaeological record in arid environments

“…The message, delivered in a variety of textbooks and journals, is that accounting for the effects of geomorphic processes on the preservation of the archaeological record is a necessary first step before behavioural analysis can proceed. As Bettis and Mandel [1] express it (p. 142), "…remains of human occupation pass through a geologic filter to become the archaeological record. The filter consists of geographic and temporal 'media' that produce a complex but patterned record that reflects the cumulative behavior of the pedologic and geomorphic systems.…”

Geoarchaeological simulation of meandering river deposits and settlement distributions: A three-dimensional approach

“…In valley systems with actively migrating channels, much material can be lost to lateral bank erosion, whereas floodplain aggradation can bury and, therefore, obscure archaeological features (Waters and Kuehn, 1996;Brown, 1997;Walker et al, 1997;Guccione et al, 1998;Waters, 2000). For example, Bettis and Mandel (2002) argue, based on a study of preserved alluvial chronologies, that cultural deposits of the Archaic period are rare in valley systems of central North America because these systems were dominated by erosion and net transport throughout much of the Holocene. The archaeology observed is, therefore, not a complete record of human activity, but a filtered record modulated by geologic processes.…”