Métodos de prospección geofísica en arqueología. Experimentación con radar de penetración terrestre (GPR) en concheros artificiales
(Geophysical methods in archaeology. Experimentation with ground penetrating radar (GPR) in artificial shell mounds)
Gustavo Bujalesky, Alejandro Montes & Fernando Santiago • español
Abstract. Archaeological sites on the northern Atlantic coast of Tierra del Fuego show a poor response to geophysical exploration, using ground penetrating radar. In order to elucidate its causes, a laboratory experiment was designed, creating the natural environmental conditions. Materials and sterile sediment from the site of La Arcillosa 2 (Chico River Basin, northeast of Tierra del Fuego) were utilized to replicate an artificial shell midden in a transparent box. Particle size analysis and magnetic separation of the sterile soil were performed, and various surveys were conducted with a 1.5 GHz antenna. The shell midden, including a deposit of sand with a moisture content between 2.1 and 4.5%, was visible in the records with the antenna. Incorporated materials generated diffraction hyperbolas and although it was possible to calculate their depth, it was not possible to distinguish their shape, composition and size. Sharper anomalies were observed for skeletal remains, due to the contrast in their dielectric properties with those of sand, however the elongated bones (ribs) did not produce recognizable abnormalities. With more than 8.5% moisture, or soil and grass cover, the results were poor. The presence of paramagnetic minerals, ferromagnetic (24.5%) and highly magnetic (3.6%), in sterile sediments caused attenuation of electromagnetic waves. Taking into account the time needed in the field and laboratory, our results indicate that the application of this method for shell mounds in northern Tierra del Fuego is not satisfactory.
Keywords: ground penetrating radar, hunter-gatherers, artificial shell midden, Tierra del Fuego.
Bujalesky, G., A. Montes & F. Santiago. 2011. Métodos de prospección geofísica en arqueología. Experimentación con radar de penetración terrestre (GPR) en concheros artificiales. Arqueología Iberoamericana 12: 3-14. http://www.laiesken.net/arqueologia/archivo/2011/12/1_en.
Publication date: 31-12-2011.
Comechingonia 16 (2012)