ARCHAEOLOGICAL GEOPHYSICAL INVESTIGATIONS AT A LATE WOODLAND EFFIGY MOUND SITE, JEFFERSON COUNTY, WISCONSIN

The sacred nature of Late Woodland (ca. A.D. 700 - 1100) effigy mound sites to Native American people and the preservation concerns for these landscape monuments requires innovative, noninvasive, and nondestructive techniques for archaeological investigation. The subsurface construction of effigy mound sites remains poorly understood. Electrical resistivity soundings, shallow electromagnetic(EM), and ground penetrating radar (GPR) were employed to assess the archaeological and geological content of Indian Mounds County Park in Jefferson County, southeastern Wisconsin. The site, protected from excavation by Wisconsin state law, is on the east shore of Lake Koshkonong. The resistivity data was interpreted with a simple three layer geologic model. The EM data shows fluctuations that may be related to the construction of the mounds. There is lower conductivity in areas of the mounds and increasing conductivity away from the mounds. GPR transects (225 and 450 Mhz) were conducted along the length and width of several mounds showing internal stratigraphy. Initial results from the geophysical data at this effigy mound site have revealed complex geological stratigraphy and cultural activity both within mound features and between the mounds. Archaeologists have treated effigy mound sites as sacred space where a limited set of activities occurred. The geophysical data from Indian Mounds Park suggest a more complex use of effigy mound sites by Late Woodland peoples.