Rinita A. Dalan

A magnetic susceptibility logger for archaeological application

Investigations of magnetic susceptibility have been used to (1) define sites, activity areas, features, buried soils, and cultural layers, (2) build and correlate stratigraphic sequences, and (3) understand site-formation and postdepositional processes. Archaeologists are limited in these endeavors, however, by the instruments available for field studies of susceptibility. A prototype instrument developed for archaeological application logs volume magnetic susceptibility down a small-diameter (ca. 2.2 cm) core-hole made with a push-tube corer. Measurements can be made rapidly, approximately 10 times faster than collecting samples either by coring or from an exposed section, to depths of 1.6 m below the surface. The prototype logger was field-tested on a mid-Holocene stratigraphic section in southeastern North Dakota where it clearly distinguished various soils and sediments, including a buried occupation layer.

Cutbank Geophysics: A New Method for Expanding Magnetic Investigations to the Subsurface Using Magnetic Susceptibility Testing at an Awatixa Hidatsa Village, North Dakota

Magnetic susceptibility investigations were conducted at an Awatixa Hidatsa village (32ME11, also known as Sakakawea Village) along a cutbank at the Knife River Indian Villages National Historic Site (KNRI) in central North Dakota, USA. This extensive exposure provided a superb opportunity to correlate magnetic susceptibility measurements with a variety of subsurface features. These features were visible in the cutbank, and also recorded in cutbank profiles completed in the late 1970s in work supervised by Robert Nickel and Stanley Ahler. The susceptibility studies are part of a larger program of geophysics at KNRI that commenced with pioneering surveys of John Weymouth and Robert Nickel, also in the 1970s, and continued with extensive surface-based magnetic surveys over the interior portion of the site in 2012 by the National Park Service. Our magnetic susceptibility study differs from other geophysical efforts in that measurements were collected from the vertical cutbank, not from the surface, to investigate different feature types within their stratigraphic context and to map small-scale vertical changes in susceptibility. In situ measurements of volume magnetic susceptibility were accomplished on the cutbank at six areas within the village and a control location off-site. Samples were collected for use in soil magnetic studies aimed at providing an understanding of susceptibility contrasts in terms of magnetic mineralogy, grain size, and concentration. Distinctive susceptibility signatures for natural and cultural soils, different feature types, and buried soils, suggest that down-hole susceptibility surveys could be usefully paired with surface-based geophysics and soil magnetic studies to explore interior areas of this and other KNRI sites, mapping vertical and horizontal site limits, activity areas, features, and perhaps even earlier occupations. This study showcases the potential of cutbank studies for future geophysical survey design and interpretation, and also underscores the importance of information gained through pioneering studies of the past.

The Cheyenne migration and the Biesterfeldt site revisited

The Cheyenne migration to the Great Plains is re-examined in light of recent archaeological work at the Biesterfeldt site in southeastern North Dakota. Biesterfeldt is regarded as an intrusion from the west rather than as the product of a farming people moving from the southeast. Woods previous analysis of Biesterfeldt is reaffirmed with the additional suggestion the Cheyenne people, regarded as the authors of the site, were by this time already established residents in the Missouri River region. This conclusion is reinforced by historical and linguistic resources, and by recent archaeological work in Biesterfeldt region. The implications of this for ethnological and historical reconstructions are briefly considered.