Archivo de la etiqueta: Geophysical prospecting

Martino, L., Bonomo, N., Lascano, E., Osella, A., Ratto, N. 2006. Geoelectrical and GPR joint prospection in the ancient Palo Blanco archaelogical site, NW Argentina, Geophysics 71(6): 193-199.

Abstract:

We conducted a geophysical survey at the Palo Blanco archaeological site located in Catamarca, Argentina. Age estimates from radiocarbon dating indicate first occupation of the site around 1500 years ago. The first description of the site was done in 1960. At that time, five residential units with different architectural arrangements were reported. These structures had different levels of deterioration caused by exposure and human activities. Some of these original structures have become completely covered by sediments. To aid in the design of efficient excavation plans, detailed maps are required to locate the buried walls. For this purpose, we conducted geophysical surveys over one of the structures. We had poor documentation about the structure at the time of the survey. Only one of the walls described in the earlier report was partially visible.We used two geophysical methods: ground-penetrating radar (GPR) and electrical resistivity. We performed 2D inversion of the resistivity data, together with numerical GPR simulations. These helped to distinguish the expected reflection events from others, aiding in a correct interpretation of the data. Finally, wemade a complementary interpretation of the resistivity and GPR data to compile a detailed map of the selected structure. We found that considering the two methods independently would have led to an incomplete map.We delineated a much more complex structure than originally expected and designed an excavation plan which was carried out. The layout of the rooms of the structure fully matched the predictions based on the interpretation used in detecting the walls and their depths. In this way, the geophysical forecasts were confirmed after excavation.

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Bonomo, N., Cedrina, L., Osella, A., Ratto, N., 2009. GPR prospecting in a prehispanic village, NW Argentina, Journal Appl. Geophys., 67 (1)80-87.

Abstract:

Palo Blanco is an approximately 1600 year old archaeological site located in Fiambalá Valley, in the Andean region of Argentina. Pioneer archaeological studies published in the 70s reported the existence of five residential units in this site. Also a small cemeterywhich included three circular tombswas discovered near to these buildings. Since that time, a profuse sedimentation covered the zone, so nowadays there are no evidences of most of these buildings on surface. Because of an imprecise location of the structures, most of the buildings became in fact missed. Then, in this work we aimed to re-localize two of the missed buildings, a residential unit and a tomb, by applying ground penetrating radar (GPR) methodology. We used fast fixed offset GPR configurations to investigate two areas inwhich these buildings could be expected.We used experimental and synthetic patterns to aid the identification of the characteristic signals due to the archaeological targets.We applied migration to the data to better define and resolve unclear anomalous signals. The employedmethodology revealed the location of both buildings. Also a number of new non-reported structures were predicted and confirmed.

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