Sod Blocks in Illinois Hopewell Mounds

Abstract

Explaining prehistoric mound development requires both anthropological and geoarchaeological perspectives. Illinois Hopewell (Middle Woodland) mounds are remarkable for the range of earthen materials used in their construction. Adding to this variety we document the presence of upturned sod blocks in a mound at the Mound House site. There and at other Illinois sites the sods have dark, 3-10-cm-thick A horizons with minimal or no evidence of B horizon development. They required no more than a few decades to form and did so under a grass cover. Humans probably created the conditions that enabled sods to form, but the sod blocks were not cut from soils adjacent to the mounds (unless from another mound surface nearby) or from soils in habitation areas. In some respects, sod blocks would have been a superior earthen building material, appropriately chosen, for instance, to construct stable, near-vertical walls of above-ground tombs. Their selection and use, however, cannot be explained solely according to principles of sound and efficient mound construction. We argue that sod blocks and other kinds of earth for Illinois Hopewell mounds surely had important symbolic dimensions in addition to their structural properties.

Geoarchaeology and Coastal Morphodynamics of Harbor Key (8MA15): Indigenous Persistence at a Partially Inundated Native Shell Mound Complex in Tampa Bay, Florida

“…First, many Gulf Coast shell mounds were destroyed during the late nineteenth and early twentieth centuries to produce material for road construction, and major portions of Gulf Coast estuaries have been heavily altered by dredge-and-fill operations, seawall construction, ditching, and other civil-engineering impacts. Second, although detailed stratigraphic-sedimentary analyses have advanced the geoarchaeological understanding of terraformed earthworks throughout the Eastern Woodlands (e.g., Arco et al 2006; Sherwood and Kidder 2011; Van Nest et al 2001), there is a lack of rigorous sedimentological research on shell mounds, which drastically limits their empirical categorization, comparison, and interpretation. For example, we note that Marquardt's (2010:551) call for a “sediment-oriented approach to the study of [shell] mound deposits” has gone largely unanswered (for an exception, see McFadden 2016).…”