A Geoarchaeological Overview of South Dakota and Preliminary

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Cheyenne; 39HK34, apparently buried in clayey, Pierre-Shale-derived colluvium, and contained in a
slump block detached from the edge of a high terrace overlooking the Cheyenne River; and 39HK45, a
paleontological site comprised of bison bone eroding from alluvial and colluvial slope deposits along a 1
km reach of the narrow valley bottom of a small to the Cheyenne River. The stream valley is deeply
incised into an extensive flat on the margin of the breaks that descend to the Cheyenne River valley
floor. Although the spatial extent of his study was limited, Fosha (1992) nonetheless documented five
different sedimentary contexts in which subsurface archaeological deposits could be found.
Grand-Moreau Tablelands
Hannenberg et al. (2010) conducted large scale excavations at 39DW165, on a highly dissected high
terrace above the Moreau River, and 39ZB31, in less dissected uplands at the south edge of the breaks
leading to the Moreau River. At both sites buried soils are present within Oahe Formation eolian
sediments, including both the late Holocene Thompson and early Holocene Leonard paleosols. At
39ZB31, the Leonard soil is preserved only in swales on the Fox Hills Sandstone bedrock surface where
it appears to have been protected from Middle Holocene deflation of the landscape. Preservation of the
Leonard paleosol in such low-lying protected landscapes is common in the Dakotas west of the Missouri
Trench (Artz 1995).
Sandstone Buttes
Albanese (1985) reported on the geology of three sites on elevated table lands in highly dissected
terrain in the vicinity of the North Cave Hills. The Holocene mantle at the sites is 55 to ca. 200 cm thick.
On the basis of buried soils, sediment textures, and radiocarbon and artifact ages, this mantle correlates
with the Oahe Formation. The Leonard paleosol formed, or is preserved, only in swales on the bedrock
surface. Although sediments in similar upland contexts are often considered eolian, Albanese (1985)
interprets the mantle as colluvial in origin. Although he does not discuss this interpretation in detail, the
implication is that sufficient topographic relief is present that sediment is subject to localized
redeposition. Eolian sediments, themselves perhaps locally derived, are subject to this reworking. The
processes responsible for reworking of sediments, however, must be relatively low energy, and episodic
in nature, or else buried soils would not form or be preserved.
Lighting Spring (39HN204) is located in a valley bottom not far from the sites described by Albanese
(1985). The site is located in a basin-like setting at the confluence of three draws that descend from
uplands. Between ca. 4000 and 1660 B.P, over 3.3 m of alluvial sediment accumulated at the site,
stratigraphically separating 13 occupation levels (Keyser and Davis 1984). Similar sites have not, to the
author’s knowledge, been identified in northwestern South Dakota or adjoining North Dakota. A search
for geomorphic settings like that of Lighting Spring might lead to the discovery of such sites.
Albanese (1999) documents three bison bone beds, stratigraphically separated in over 3 m of
Holocene colluvium at 39HN176. A surface soil and two buried soils indicate that deposition was
episodic, over a period of ca. 330 years, as suggested by radiocarbon ages. As part of this report
Albanese (1999) also documents the effects of landslides, including rotational slumping and the
formation of boulder talus slopes on the landscape and archaeological sites.
Fosha and Albanese (1998) provide a brief report on the Summit Spring site, 39HN569, in the Slim
Buttes. At this butte-top site, Late Prehistoric through Early Archaic archaeological deposits are buried
in a Holocene sediment mantle that ranges from 15 to 455 cm thick. As at the three North Cave Hills
sites (Albanese 1985), the butte-top sediments are identified as “alluvial-colluvial” in origin, suggesting
low-energy, nonerosive, and localized movement of sediments through time.
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