Paleo-environmental characterisation of an archaeological site through multi geophysical techniques and stratigraphic analysis

The Neolithic settlement of Favella della Corte (Cosenza, Southern Italy) provides an important opportunity to investigate prehistoric Southern Italian communities. This work presents the results of sedimentological analysis on outcropping stratigraphic units coupled with a non-invasive geophysical investigation of the site. Specifically, a multi approach geophysical survey has been conducted, including magnetic field measurements, magnetic susceptibility sampling and electrical resistivity profiling. This study aims to provide a detailed characterisation of the site’s shallow stratigraphy and to support the reconstruction of its paleo-environmental context.

The magnetic survey consisted of approximately 3,000 measurements acquired over an area of 11,600 m² using a Scintrex MP3 Proton Procession Magnetometer (PPM). Magnetic susceptibility was measured on exposed stratigraphic units along vertical sections, with sampling intervals of 20–50 cm, using a portable Geofyzika KT-5 kappameter. Electrical resistivity data were collected along nine profiles spaced 20 m apart, each extending up to 90 m in length. Measurements were carried out using a geo-resistivimeter designed and built by the Applied Geophysics Laboratory of the University of Genova.

Sedimentological analyses revealed the alternation of three shallow levels: (i) an upper arable layer, (ii) an intermediate silty sand layer, and (iii) a deeper silty-sandy gravel layer. Magnetic susceptibility data supported this evidence, highlighting a contrast between the more susceptible intermediate horizon and the underlying gravel level. Therefore, the magnetic inversion was constrained to a single layer of prismatic bodies, enabling the reconstruction of the interface between silty sand and silty-sandy gravel units. Because of the non-linearity of the inverse problem, the L-BFGS algorithm has been employed to solve the optimization problem. The model parameters involved are the depth of the bottom of each prism and a single value of magnetic susceptibility contrast associated with all the prisms. These parameters were updated at every iteration until the L-BFGS algorithm converged. The electrical resistivity data have been modelled along two-dimensional sections using Res2dinv software based on the smoothness-constrained least-squares method without any constraints due to the absence of a priori information (e.g. water table depth, homogeneity degree and resistivity values of the lithological units).

Combined modelling of magnetic and electrical resistivity datasets has revealed a NE–SW trending linear feature 70m long, 15m wide and reaching depths of about 4m, crossing the whole survey area. The sedimentological evidence resulting from outcropping stratigraphic units allowed us to interpret it as a paleo-channel carved into the silty-sandy gravel substrate and filled with silty sand material. Considering the pronounced straightness of this feature, we interpreted it as an anthropogenic paleo channel with a drainage function. Although of unknown age, the paleo- channel may have controlled the distribution of the Neolithic settlement of Favella della Corte.

The coupling of magnetic and electric resistivity techniques has proved to be highly effective for reconstructing the paleo environmental context of the Favella della Corte area, revealing subsurface stratigraphy and a geomorphological feature. These findings have highlighted the value of integrated geophysical approaches for reconstructing ancient landscapes and informing future research.