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 Conical Mound. The black oval in the top image is a tree and the black rectangle is a bench. The mound is clearly defined in the lower middle of the image, outlined in green. The tree was partially in the mound and a disturbance can be seen in the data. The strength of the disturbance, however, suggests that there may be some other magnetically sensitive feature in this area. Viewing the main body of the Conical Mound, we can see an interesting distribution of magnetic values. In the top image, the base of the mound can be seen rising from the earth at the green and red interface. The higher magnetic value represented by yellow is not evenly distributed within the mound. An area in the middle of the mound appears red, with a lower magnetic value. In the 3D Contoured Map, this effect is even more pronounced, showing the upper right section of the mound as having peak magnetic values.