THE EFFECTS OF LATE QUATERNARY LANDSCAPE EVOLUTION ON THE ARCHAEOLOGICAL RECORD OF THE MINNESOTA RIVER VALLEY

The record of human occupation in the Minnesota River valley (MRV) spans the past 13,500 years and may go further back in time. Although the number of recorded sites in the MRV that can be assigned to a cultural tradition is substantial (200 sites as of 2014), 147 of those sites (73.5%) are Woodland or younger occupations and, therefore, are less than approximately 2,000 years old. The paucity of recorded pre-ceramic sites may be related to lower population densities in the MRV prior to 2000 B.P. compared to population densities during later periods. However, the effects of geomorphic processes on the archaeological record also must be considered. For example, between ca. 11,900 and 10,800 ¹⁴C yr B.P., catastrophic flooding in the valley of Glacial River Warren, which is now occupied by the Minnesota River, may have removed Early Paleoindian cultural deposits.  

The purpose of this paper is to describe the evolution and geomorphology of the MRV, mostly based on the work of Herb Wright and others, and to address how geomorphic processes, especially erosion and deposition, have affected the temporal and spatial pattern and detection of archaeological sites in the MRV. By combining information gleaned from the Mn/Model (Hudak and Hajic 2001) and other sources, a simplified model of late-Quaternary landscape evolution was developed. This model serves as guide to address such issues as where archaeological deposits with specific cultural affiliations are likely to be preserved, where they were likely removed by erosion, where they are likely to be buried and undetectable using surface-orientated survey techniques, and how patterns in the sedimentary record might affect patterns in the archaeological record.