Pedogenesis of Cotiga Mound, a 2100‐Year‐Old Woodland Mound in Southwest West Virginia

Abstract

Cotiga Mound, an Early Woodland mortuary mound constructed 2100 YBP, was sampled to evaluate diagnostic horizon development during a well‐defined, relatively short period of time. Five columns (profiles), three of which extended into the submound terrace soil, and one Giddings core of the terrace soil were sampled for particle‐size, pH, organic C, and micromorphology analysis. Six additional cores were collected to characterize the terrace soil. The mound was constructed of acid, silty material, in a manner that resulted in basketloading macrofabric consisting of long, sinuous, thin layers contrasting in color and texture. Pedogenesis destroyed the macrofabric and formed a solum in the upper 0.75 to 1.0 m of the mound. The solum consisted of a thin, dark A horizon; and intermittent, thin E horizon; and a variable B horizon. The B horizon was thickest at the mound crest, contained clay films on ped surfaces, and was designated Bt. On side slopes, the B horizon was thinner, lacked clay films, and was designated Bw. No B horizon was formed at the mound periphery. Clay distribution indices indicated that the Bt horizon was borderline cambic‐argillic, consistent with those typical of 2000‐yr‐old mid‐Atlantic alluvial soils. Clay films were sparsely distributed throughout the mound, indicating that clay accumulation mechanisms were largely inefficient in the 2100 yr. Mound soils were classified as Typic Dystrochrepts grading to Typic Hapludults at the mound crest. These soils are similar to floodplain soils mapped nearby. Submound terrace soils and adjacent terrace soils were classified as Humic Hapludults.

Micromorphology of Cotiga Mound, West Virginia

“…The Bt horizon of the natural soil has a sufficient clay increase, as well as clay films on ped surfaces to classify it as an argillic horizon (Soil Survey Staff, 1999). No pedogenic characteristics were found between the base of the terrace solum and a depth of 5 m. The age of the terrace was estimated at 5000-8000 years, based on pedogenic development (Cremeens, 1995). Figure 1 for site-specific northing grid.…”

“…On a microscopic scale, the c/f-RDP of most of the mound fill samples are open to double-spaced a porphyric reflection of the silty texture of the mound materials (Cremeens, 1995). A few samples contained a c/f-RDP grading to either enaulic or gefuric.…”

“…The mound, constructed of acidic, silt-loam sediments, was completely excavated in the early 1990s (Cremeens, 1995;Cremeens et al, 1997). The modern surface soil was developed in the upper meter of mound fill, and the mound buried a relatively undisturbed soil formed in the underlying terrace fill.…”

The potential for criticality following disposal of uranium at low-level waste facilities: Uranium blended with soil

“…While studying soils in Pennsylvania, Bilzi and Ciolkosz (1977) found that between 2000 and 3000 years were required on a stable geomorphic surface and in noncalcareous parent materials for processes of soil genesis to translocate enough clay particles from surface soil horizons to form a detectable subsoil clay-enriched horizon. Cremeens (1995) reported the results of a study of soil genesis on a 2 100-year-old Native American mound in southwest West Virginia. On the geomorphically stable mound crest, soil genesis had produced horizons to a depth of 0.75 to 1.0 m. He found that very little clay movement took place during 2100 years.…”

Complex pedostratigraphy of a terrace fragipan at the Memorial Park site, central Pennsylvania

“…The degree of soil horizon development, particularly diagnostic subsurface horizons, has been used to infer the chronologic age of alluvial landscapes when calibrated with radiocarbon and artifact dating (Bilzi and Ciolkosz, 1977;Cremeens, 1995;Foss et al, 1995). Diagnostic subsurface horizons provide geoarchaeological investigations with an important tool for defining and correlating geomorphic units in alluvial settings (Ferring, 1992;Foss et al, 1995).…”