A Geoarchaeological Overview of South Dakota and Preliminary

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One finding was that the stream valley floors are underlain not only by alluvium from the stream itself,
but also by alluvial fans that spread from tributary valleys, and coalesce into aprons along the valley
margin, extending well out into the valley.
Kuehn (2003) examined landforms and cutbank stratigraphy in several areas of Badlands National
Park. He, like Winham and Hannus (1990), calls attention to sod tables as important locations for
archaeological sites. These are flat-topped erosional remnants of formerly more extensive valley floors
and colluvial slopes. Sediments are well exposed around the edges of the tables, creating good exposures
for archaeological deposits. Kuehn (2003) also examined sand sheet and dune deposits on upland and
high strath terrace surfaces. Buried soils correlative to the Oahe Formation occur in these deposits. He
reviews radiocarbon ages from alluvial contexts (e.g., Kowal 1997).
Rawlings et al. (2003) examined buried soils formed in eolian deposits at the edges of high tablelands
in the Badlands, referring to these landforms as “eolian cliff-top deposits.” Radiocarbon and optical spin
luminescence dating indicate that soils formed in the eolian cliff-top sediments at intervals during the
late Holocene. The deposits accumulated on a soil surface that formed in the early Holocene.
Lower White
Donohue (2001) investigated 39TP30, where archaeological deposits are contained in the upper part
of a 380-cm-thick Oahe Formation eolian mantle on a terrace ca. 70 m above the White River. Buried
soils were present, the uppermost yielding Extended Coalescent artifacts. The age of the lower soils was
not determined.
MISSOURI TRENCH
Several studies identified by the search deal with the Missouri Trench as a whole. These include
Coogan (1987), Coogan and Irving (1959), and McFaul (1985, 1986).
Bad-Cheyenne
Brakenridge and McReady (1988) mapped the alluvial terraces of the lower Cheyenne River valley in
the ca. 50-km-long stretch that is subject to inundation by Lake Oahe. They relate the terrace sequence
to the MT terrace system of Coogan (1987). They examined historic channel changes of the river by an
examination of early maps. Information about terrace stratigraphy was obtained from lake-eroded
cutbanks, at least one of which exposed the Leonard paleosol.
Artz and Toom (1985) focused on areas on the west side of the Missouri Valley, above and below the
Lake Oahe dam. They mapped the MT terrace sequence as found in this study area, and described
several cutbank exposures of alluvium and eolian sediments. Their archaeological survey encountered
buried archaeological sites exposed in cutbanks in the lower reaches of tributaries valleys, surfaces, in
eolian deposits on an MT-3 terrace, and in an artificial ditch on the MT-1 terrace. The latter discovery
was a human burial.
Big Bend
Coogan (1987; Coogan and Irving 1959, Coogan 1960) did considerable work in the Big Bend region,
establishing the terrace sequence and stratigraphy. Detailed descriptions by Coogan and Irving (1959)
include ones of MT-2 exposures at the Crow Creek (39BF11) and Medicine Crow (39BF2) sites (Ahler
and Toom 1989; and Zimmerman et al. 1981). Irving’s work at Medicine Crow was the basis of Ahler
and Toom’s (1989) detailed discussion of the geological context of pre-Plains Village components at
that site.
McFaul (1986), Picha and Toom (1984), Toom (1992), Toom and Steinacher (1980), and Toom et al.
(1988) describe the stratigraphic context of 25 archaeological sites on Lakes Sharpe and Francis Case, in
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