A harbour–canal at Portus: a geoarchaeological approach to the Canale Romano: Tiber delta, Italy

Abstract

This paper presents a detailed description of the sediments trapped by the Canale Romano in the Imperial harbour complex of Portus (Rome). The study confirms the hypothesis of a Roman canal (active during the early 2nd century ad and the 3rd/5th century ad) with a maximum water-depth between 4.36 and 7.37 m. The function of this canal as a harbour seems to particularly fit with the data available. This study follows a multidisciplinary approach. It combines all previous data available on the Canale Romano (geophysical surveys, archaeological and historical data) and provides a new palaeoenvironmental dataset in order to draw a more complete overview about its history. Three cores drilled in the Canale Romano are analyzed using sedimentological data, CM diagram and bioindicators, 14C and archaeological data. Four main sedimentation phases were identified: (1) Pre-canal deposits; (2) relatively quiet fluvial environment deposits; (3) flood sediments inputs; and (4) fine sediment infill after the cut-off of the canal. In the discussion, the paper attempts to put this stratigraphic sequence into context of the reorganization of the harbour of Imperial Rome during the reign of Trajan (early 2nd century ad) and its subsequent evolution.