North American Database of Archaeological Geophysics
North American Database of Archaeological Geophysics
Abstract/Summary:
Project Name: Steamboat North Alabama, SD;
Reference: DeVore, S.L. (1998). Electromagnetic Conductivity Investigations Searching for the Buried Steamboat "North Alabama" in Clay County, South Dakota. National Park Service, Intermountain Support Office, Denver, Colorado. Submitted to the Archaeology Laboratory, University of South Dakota, Vermillion, South Dakota.
On the return trip from the Montana frontier in the 1870s, the "North Alabama" hit a snag in a bend of the Missouri River and sank. According to Dr. Larry Bradley, the steamboat sank without being recovered. Apparently the remains of the boat were uncovered for a short period of time in 1907 following a flood. Today the proposed location of the buried steamboat is in a Missouri River meander scar.
Electromagnetic conductivity and magnetic susceptibility surveys were conducted at the request of Nancy J. Hodgson of the Archaeology Laboratory, University of South Dakota. The search was conducted as part of the University of South Dakota's archeological investigations of a proposed bridge replacement project with the South Dakota Department of Transportation. The abandoned Missouri River meander is reflected in the conductivity data set as a high conductivity area. A smaller potential channel and an area of low conductivity were also identified. In the magnetic susceptibility survey data, a large rectangular area of relatively high susceptibility was identified. An area of low susceptibility was identified just to the east of this area. Three additional areas of high magnetic susceptibility were also noted.
The present geophysical project has identified several anomalies for further archeological investigations. Ground truthing is important at this phase of the geophysical investigations in order to determine the cause or nature of these anomalies. The preliminary results of this investigation indicate that the use of the EM31 for the search for a buried steamboat may have a practical application to this type of archeological investigation.