Archaeological Geophysics
Putnam County, WV       

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This geophysical survey was conducted at the Putnam County Development Authority (PCDA) site located southeast of Fraziers Bottom, West Virginia by D’Appolonia Environmental Services, Inc. (D’Appolonia) on behalf of Dr. Gloria Gozdzik, Horizon Research Consultants of Morgantown, West Virginia. The geophysical survey was conducted by Bill Johnson and Don Johnson between April 17 and May 1, 2003.  The investigation consisted of magnetometer, resistance, and resistivity surveys.

The objective of the investigation was to apply geophysical technology to identify possible prehistoric cultural features in a 10-acre (4 hectare) site adjacent to the Kanawha River about one mile southeast of the town of Fraziers Bottom, West Virginia.  The property is being considered for development by the PCDA.  Phase I level archaeological studies over the entire property were conducted in the 1990s and prior to this study the northern part of the site had been identified as site 46PU159.  The Phase I survey encountered 1,036 artifacts from systematic collection at 171 locations and five trenches.

Putnam Co Map

The Phase I study determined that 46PU159 extends southward through the entire site and probably farther south.  Artifact density was found to be greater on the portion of the site with a higher elevation, identified as being a natural levee.  The “levee” portion of the site is found between site eastings of about 30 to 60 meters.  Artifacts recovered from the site indicate use of the site during the Early and Late Archaic and the Early, Middle and Late Woodland periods.  Artifact classes identified (chert, debitage, projectile points, scrapers, drills and a single pottery sherd) suggest that this multi-component prehistoric site may have been used either as a resource extraction camp, a seasonal habitation site, or both of these types of site during its long period of use.

Putnam Co Magnetics

In addition to the plow furrows (oriented to grid north), the vertical magnetic gradient map shows numerous small magnetic highs that are concentrated on the crest of the levee.  Based on their shape, the anomalies do not appear to be associated with metal nor do they appear to be of geologic origin as the levee and terrace soils are fine grained and typically would not include cobbles or boulders that could produce the anomalies observed.  Where they are not otherwise associated with resistance lows (interpreted to be pit features), the magnetic anomalies are interpreted as being associated with prehistoric cultural features such as fire hearths .

Putnam Co Resistance

The resistance map shows higher resistance values associated with top of the levee and lower resistance values east of the levee.  As levees are formed as overbank deposits under flood conditions, it is not unexpected that the levee would have a higher sand content and a corresponding higher resistivity than the lower terrace area.

A significant observation from the resistance measurements is the presence of 43 discrete low resistivity anomalies.  These are interpreted to be pit features.  Some of the most prominent resistivity lows are associated with magnetic highs with the most prominent of these features being located at 72E, 250N and 65E, 239N.  We have observed similar associated anomalies with pit features at other prehistoric sites.

Putnam Co Resistivity

Resistivity surveys provide depth information not provided by typical resistance surveys.  We collected resistivity data to provide cross sections through selected interpreted pit features as well as to provide cross sections of soil stratigraphy. 

The E-W resistivity profiles indicate that the terrace area is a soil of lower resistivity (probable higher clay content) that drapes over a higher resistivity soil that appears to be contiguous with the soil at the top of the levee.  The thickness of the terrace soil in the eastern part of the area investigated (east end of Line 4) is about 2.5 to 3 meters.  This suggests that younger sediments cover an older land surface where additional archaeological features could be encountered.  Resistivity cross section over interpreted pits indicate these features to be 1 to 2 meters deep.

Putnam Co Interpertation

The fundamental observation is that most of the geophysical anomalies interpreted to be of cultural origin are located on or near the top of the levee.  The flat terrace surface on the river side (east side) of the levee is relatively featureless.

North of about 180 meters North, the relatively high resistance values correspond closely with the crest of the levee.  South of about 180 meters N, however, the highest resistance values follow a band on the eastern slope of the levee and not on the crest itself.  This pattern does not have an obvious geologic origin and leads to the speculation that the distribution of the resistivity highs does not reflect geology, but is a result of human occupation as might be associated with soil compaction from a concentration of living areas.  The resistivity profiles indicate that the resistance highs in the northern part of the site are a thin layer, corresponding to the top meter of soil, which could support the concept that the anomalies are caused by soil compaction.