North American Database of Archaeological Geophysics
North American Database of Archaeological Geophysics
Graphic/Image:
Project Name: Effigy Mounds, IA (5);
Reference: Watters, M.S. (1999). Geophysical Work Conducted with the Geometrics G858 Cesium Vapor Magnetometer at Effigy Mounds National Monument, IA. As part of the U.S. National Park Service Workshop: "Recent Advances in Archeological Prospection Techniques," May 10-14, 1999. Submitted to the Midwest Archeological Center, U.S. National Park Service, Lincoln, Nebraska.
Magnetic gradient of the Linear Mound. The above images display the magnetic gradient of the survey conducted over one full Linear Mound and part of a second. The upper right corner of the survey area contained a bench and trashcan, both containing iron. The partial mound appears faintly to the left of the complete mound. The Linear Mound is well defined. It appears to be outlined with a ring of lower magnetic material. The survey surface was grass and did not reveal any suggestion of the structure within the mound that is visible through the magnetic data. The left two thirds (3m-27m) of the mound appears to have two parallel lines of earth defined by higher magnetic values sparated by a material of a lower value. Both of these sections are divided very clearly by a line at 27m.