MAKING RAPID CULTURAL RESOURCE MANAGEMENT DECISIONS USING GROUND-PENETRATING RADAR

Aboriginal shell middens are found along many of the world’s coasts. However, climate-driven coastal erosion and sea-level rise threaten many of these important cultural and paleoenvironmental archives. Focused on representative middens located on the Maine coast, this research demonstrates the utility of Ground-Penetrating Radar (GPR) as a rapid, cost-effective, and noninvasive alternative for delineating the extent of shell middens and their complexly interbedded strata. In Maine, over 2000 aboriginal shell midden sites are composed of centimeters to meters of clam and/or oyster shells, other faunal remains, and artifacts. These features record up to approximately 5000 years of human coastal adaptation and paleoenvironmental conditions along the western Gulf of Maine coastline. Virtually all have experienced recent erosion, and some recorded sites have disappeared in the 2-3 decades since identification. Traditional methods of investigating the complex lateral and vertical stratigraphic extent at each midden site require labor- and time-intensive, destructive excavation methods. This study combines GPR stratigraphic profiles, produced by differences in electrical properties of the strata, with limited existing archaeological excavation data available for each study site. As a result, shell-rich layers and interlayered soil horizons can be identified across the site, as well as prior excavation units and the nature and geomorphology of underlying material. While not producing the detailed results of an archaeological excavation, a GPR survey provides a powerful tool for shell midden analysis. In particular, the use of GPR at shell midden sites has demonstrated the method’s effectiveness with respect to the identification of site boundaries, features of interest, and the recognition of complex stratigraphy for cultural resource management decisions with substantially less field-related time and labor as compared to traditional methods.