Electrical Resistivity Tomography as a guideline for detecting altered volcanic ash deposits

Vittorio Longo (a), Valeria Testone (a), Giacomo Oggiano (a) & Andrea Testa (b)
(a) Department of Science for Nature and Environmental Resources, University of Sassari, Via Piandanna 4 – 07100 Sassari, Italy. E-mail: vlongo@uniss.it (b) Minersarda spa, Italy.

In this paper we propose the application of Electrical Resistivity Tomography (ERT) as a guideline to localize and characterize altered volcanic ash deposits quickly and reliable. The geophysical method was tested on an altered epiclastic layer, identified within a composite Oligo-Miocene volcanic succession in central Sardinia (Italy). The equipment employed in continuous current mode (DC) was a Terrameter SAS 1000 (ABEM, Inc.) based on the use of metal electrodes for galvanic coupling. The high resistivity contrast between the epiclastite and the overlying ignimbrite, allowed the ERT method to provide valuable indications about the locations, lateral continuity and thickness of the deposit.

Electrical Resistivity Tomography, Mineral exploration, volcanic ash deposits, Sardinia.