Geoarchaeological study of karst depressions integrating geophysical and sedimentological methods: case studies from Zominthos and Lato (Central and East Crete, Greece)

This paper aims to investigate the link between karstic depressions, their geomorphological characteristics and their significance for human occupation in Central and East Crete. Two different sites, Zominthos and Lato, are of high archaeological interest due to the existence of important settlements from Minoan to Hellenistic times. For the first time, a geoarchaeological approach based on geophysical and sedimentological studies was carried out in distinct areas with similar geological and geomorphological backgrounds. Field observations as well as Earth Resistivity Tomographies (ERT) were conducted and revealed both the heterogeneous buried karst topography with thick sedimentary infills of up to 20 m below the surface and the presence of archaeological structures in the subsurface. The latter clearly indicate the former anthropogenic use of karst depressions for settlement and agricultural activities. A Geographic Information System (GIS) was elaborated in order to create a common geodatabase and to generate perspective 3D views of the findings. Moreover, three boreholes (Z1, Zominthos; D4A and D4B, Lato) were drilled up to a maximum depth of ten meters and corresponding sediments were used for grain-size analysis, magnetic susceptibility (chi) measurements and X-Ray Diffraction (XRD). As highlighted by the results, the investigated dolines do not only show colluvial fills, but also exhibit semi-fluvial sediments and residual clay deposition typical of terra rossa soils. Therefore, we can infer different and alternating periods of geomorphodynamic activity and stability that established the landscape evolution during the mid- and late-Holocene. Ancient human societies certainly decided to occupy Cretan karst depressions in areas with difficult topographic relief on purpose. The favourable environmental settings in such regions evidently outweighed the negative effects of their remoteness.