HR: 0830h
AN: NS41A-01    [Abstracts]
TI: Archaeological Feedback as a Research Methodology in Near-Surface Geophysics
AU: * Maillol, J
EM: maillol@ucalgary.ca
AF: Dept. of Geology and Geophysics, University of Calgary 2500 University Dr. NW, Calgary, AB T2N1N4 Canada
AU: Ortega-Ramírez, J
EM: magemita@yahoo.com.mx
AF: Laboratorio de Geofisica, INAH, Mexico, DF Mexico
AU: Berard, B
EM: bberard@ucalgary.ca
AF: Dept. of Geology and Geophysics, University of Calgary 2500 University Dr. NW, Calgary, AB T2N1N4 Canada
AB: A unique characteristic of archaeological geophysics is to present the researchers in applied geophysics with the opportunity to verify their interpretation of geophysical data through the direct observation of often extremely detailed excavations. This is usually known as archaeological feedback. Archaeological materials have been slowly buried over periods ranging from several hundreds to several thousands of years, undergoing natural sedimentary and soil-forming processes. Once excavated, archaeological features therefore constitute more realistic test subjects than the targets artifically buried in common geophysical test sites. We are presenting the outcome of several such verification tests aimed at clarifying issues in geometry and spatial resolution of ground penetrating radar (GPR) images. On the site of a Roman villa in SE Portugal 500 Mhz GPR images are shown to depict very accurately the position and geometry of partially excavated remains. In the Maya city of Palenque, Mexico, 900 Mhz data allows the depth of tombs and natural cavities to be determined with cm accuracy. The predicted lateral extent of the cavities is more difficult to match with the reality due to the cluttering caused by high frequency. In the rainforest of Western Africa, 500 MHz GPR was used to prospect for stone tool sites. When very careful positioning and high density data sampling is achieved, stones can be accurately located and retrieved at depths exceeding 1 m with maximum positioning errors of 12cm horizontally and 2 cm vertically. In more difficult data collection conditions however, errors in positioning are shown to actually largely exceed the predictions based on quantitative theoretical resolution considerations. Geophysics has long been recognized as a powerful tool for prospecting and characterizing archaeological sites. Reciprocally, these results show that archaeology is an unparalleled test environment for the assesment and development of high resolution geophysical methods.
DE: 0600 ELECTROMAGNETICS
DE: 0999 General or miscellaneous
SC: Near-Surface Geophysics [NS]
MN: 2005 Joint Assembly