The modeling of archaeological and geomorphic surfaces in a multistratified urban site in Padua, Italy

Multistratified archaeological sites are important archives of past human activities, recording the superposition of anthropogenic deposits over centuries and millennia. We attempted the reconstruction of buried geomorphic and archaeological surfaces in the 1.55 km(2), 7 m thick, multistratified urban site of Padua in northern Italy, through the spatial interpolation of 117 elevation points relative to unique archaeological features. Key data were the elevations above sea level of ancient surfaces and features, such as the presettlement alluvial plain, roads, floors, and hearths dating from Bronze to Imperial Roman ages. Present surface elevations were provided by a Light Detection and Ranging (LiDAR) digital elevation model. Spline interpolation produced general-trend surfaces of the buried alluvial plain, Iron Age (13th-10th and 6th centuries B.C.), and Roman (first century B.C. and first to second centuries A.D.) levels. Validation of the later Roman surface indicates a decimeter accuracy of interpolation. Geographic information system overlay operations resulted in quantitative estimates of the vertical growth of the site, the volumes of archaeological deposits, and the depth of burial of the different levels. This research provided new insights on the development of the ancient city and its relations with paleohydrography, representing a starting point for the assessment of buried archaeological heritage.