North American Database of Archaeological Geophysics
North American Database of Archaeological Geophysics
Graphic/Image:
Project Name: Petaluma Adobe State Historic Park (CA-Son-2294/H), CA;
Reference: Silliman, S.W., Farnsworth, P., and K.G. Lightfoot (2000). Magnetometer Prospecting in Historical Archaeology: Evaluating Survey Options at a 19th-Century Rancho Site in California. Historical Archaeology 34(2):89-109. (used with permission).
Silliman, S.W. (2000). Colonial Worlds, Indigenous Practices: The Archaeology of Labor on a 19th-Century California Rancho. Ph.D. Disseration, University of California-Berkeley.
Comparison of proton precession gradiometer image to proton precession magnetometer images created with different sensor heights. a: Proton precession gradiometer image, 1.0 x 1.0 m sampling interval, 0.5 nT/m contour interval, range of -35-50 nT/m. b: Proton precession magnetometer image with 1.5 m sensor height, 1.0 x 1.0 m sampling interval, 0.5 nT/m contour interval, range of 50,223-50,307 nT. c: Proton precession magnetometer image with 0.75 m sensor height, 1.0 x 1.0 m sampling interval, 0.5 nT/m contour interval, range of 50,173-50,384 nT. The linear cobble feature represents fluvial deposits beneath the historic cultural deposits. The refuse features consisted of fire-cracked rock and metal objects in addition to a variety of non-metallic artifacts.