On the characterization of temporal and spatial patterns of archaeological crop-marks

Crop-marks are the most important proxy indicators of the presence of archaeological buried remains. Their characteristics and information provided on human past depend on the nature of expected features, land use, meteorological parameters, soil and vegetation types. The interaction of these factors is crucial for the major and minor visibility of crop-marks over seasons. Hence, the need to improve the knowledge of 'vegetation-mark phenomenology' by a multi-temporal investigation. This can be based on a holistic approach jointly using aerial prospection, information on meteorological conditions and in situ survey of soil and vegetation. Today, the availability of low cost Unmanned Aerial Vehicle (UAV) makes this approach feasible, as discussed in this paper. Herein, a multitemporal analysis from March to October 2014 has been conducted on a test site selected in the Tavoliere delle Puglie. It is one of the richest European areas in archaeological crop-marks because of the long and intense human frequentation (from Neolithic to Modern Ages) and the geo-pedological conditions which favoured the preservation of crop marks. In particular, results from the aerial observations evidenced not only during the spring season the expected crop-marks, due to cultivation, but, also, in August and October, weed marks linked to spontaneous herbaceous mainly growing due to favoured meteorological conditions (especially rain). Outputs from our investigations revealed new insights on the characteristics archaeological vegetation marks in relation with vegetation types and meteorological conditions.