STREAMLINING GEOPHYSICAL SURVEY TECHNIQUES FOR CULTURAL RESOURCE MANAGEMENT ARCHAEOLOGY

In this presentation we discuss how the regular use of geophysical survey has impacted and changed the way in which we do Cultural Resource Management (CRM) studies in the Midwest U.S. Through a combination of geophysical survey and minimally invasive ground truthing, we have devised a method that improves our cost effectiveness and the success of our archaeological investigations while at the same time minimizing unnecessary digging.

Geophysical survey has become an indispensable tool for investigating and evaluating archaeological sites. In the Eastern U.S. traditional archaeological investigations involve various levels of hand and mechanical excavation to identify sub-plowzone archaeological features, such as prehistoric cooking hearths, storage pits, and post-molds, as well as historic privies, cisterns, and basements. But these techniques are time and labor intensive and their results can be unpredictable. This should be particularly worrisome to archaeologists, especially in a CRM context, where the archaeological resource is slated for destruction. While the traditional techniques, such as plowzone removal over small areas with heavy equipment, have been in use for decades and have proven useful, the chance of identifying subsurface features on most sites is hit-or-miss. Using geophysical survey, however, we have devised a method for consistently locating larger (40+ cm in diameter) types of subsurface cultural features.

Based on results from over 50 magnetic gradient survey projects on archaeological sites in Ohio, we have arrived at a three-step process that is exceptional at consistently locating near-surface cultural features on nearly all kinds of prehistoric and historic archaeological sites. Our three-step technique includes: (1) conduct a magnetic gradient survey, (2) ground truth select magnetic anomalies with a coring device, and (3) conduct small-unit hand excavations of select, positively cored anomalies. Only rarely do we need to use a second geophysical instrument. Through the systematic application of this technique, with a clear set of project objectives, we can consistently identify cultural resources important to assessing the eligibility of archaeological sites for inclusion on the National Register of Historic Places.