Geophysical imaging of Etruscan orientalising burials obtained via multi-parametric approach: The Grotte di Castro case study
Abstract
Grotte di Castro is a medieval (IX-X c.) village within the Viterbo province, about 100 kilometres N-NW from Rome, close to the border between Lazio, Toscana and Umbria. It lies on a tuff ridge which, as many others in the area, is the result of the deposition and subsequent weathering of volcanic ashes from the Latera Volcanic Complex (160 - 145 ka). The study area interests a portion of one of the several funerary areas pertaining to the Civita Etruscan settlement whose remains occupy the wide tuff plateau rising 0.5 km SE from the modern village. In this area, we acquired high resolution geophysical and geochemical data to accurately map the presence of Etruscan orientalising buried tomb. Very high spatial resolution digital elevation model and orthomosaic of the entire survey area have been obtained by means of 'Structure-from-Motion' photogrammetry. Capacitive-coupled resistivity tomography (CCR) and ground penetrating radar (GPR) measurements have been carried out over coincident profiles to depict the electrical and the electromagnetic signatures of these archaeological targets. To cross-check the CCR recovered resistivity models we also acquired an electrical resistivity tomography profile (ERT) and compared output models over one CCR survey line. Radon measurements have been performed to map gas concentrations in order to highlight the presence of subsurface structures in correspondence of CCR and GPR profiles. Geophysical results highlighted the presence of high resistivity, regular-shaped, reflection anomalies that we interpreted as due to the presence of small cavities with the top at about 2 m depth. Slight anomalies of radon in soil have been found in correspondence of the depocenter of the geophysical anomalies. We show the advantage but also the limitations of using capacitive resistivity methods as compared to traditional galvanic resistivity tomography. In addition, we explored the benefit of data integration using GPR reflections as a-priori information to constrain CCR and ERT output resistivity models. The joint use of CCR, GPR and Radon data have proved to be an efficient tool to rapidly and accurately image shallow archaeological tombs. We claim that this multi-parametric approach has the potential to contribute to the investigation of similar archaeological and geological settings.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMNS43C0849C
- Keywords:
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- 0915 Downhole methods;
- EXPLORATION GEOPHYSICS;
- 0925 Magnetic and electrical methods;
- EXPLORATION GEOPHYSICS;
- 0935 Seismic methods;
- EXPLORATION GEOPHYSICS;
- 0205 Archaeological geology;
- GEOHEALTH