LATE PLEISTOCENE THROUGH HOLOCENE WINDBLOWN SEDIMENTS AND THE POTENTIAL FOR ARCHAEOLOGICAL SITE BURIAL IN INDIANA AND OHIO

Windblown, or eolian, sediments blanket portions of high terraces in alluvial valleys and upland settings throughout the Midwestern U.S. Eolian sedimentation traditionally is thought to have occurred during the late Pleistocene soon after the Last Glacial Maximum (~21 ka) and largely prior to human occupation of eastern North America. In contrast, recent geochronological research, primarily optically stimulated luminescence dating, demonstrates that considerable reactivation or remobilization of eolian sediments occurred during the late Pleistocene and Holocene, often in response to periods of increased aridity or wildfire activity.

The potential that post-14.5 ka eolian sediments blanket currently undocumented archaeological sites in the Midwestern U.S. has received limited attention. A cursory literature review illustrates that post-14.5 ka eolian sediments are common east of the Mississippi River where they form various landforms and mantle pre-existing, older surfaces. At least 50 optically stimulated luminescence and radiocarbon dates between 14.5 and 0.22 ka have been reported from non-coastal eolian settings in Illinois, Indiana, Ohio, Michigan, and Wisconsin.

The potential that post-14.5 ka eolian processes have buried archaeological resources up to 7 m below modern Midwestern U.S. surfaces is considered. Research includes review of existing geomorphological and archaeological literature, coupled with new sedimentological and geochronological data from northern Indiana and southern Ohio. This research highlights that late Pleistocene and Holocene eolian sediments are common on many high alluvial terraces, paleochannels, relict dunefields, and upland plains away from active floodplains. Since current archaeology methods, especially within cultural resource management, typically do not recommend deep testing on these landforms, archaeologists risk missing significant portions of the archaeological record if deep testing is not conducted. At least one example of a buried archaeological site (Harper Site, 12La202) has been identified in the literature and recent fieldwork documents several Holocene buried soils in relict dunes. Finally, this research reports on recent attempt to distinguish eolian from alluvial sediments through particle-size analysis.