Where is the ancient harbour of Utica ? Geoarchaeology and palaeoenvironment of the Medjerda delta (Tunisia)

Abstract

Ancient authors mention Utica as a maritime and port city and estimate its origin around the 11th c. BC. However, in the present state of research, no archaeological evidence is earlier than the 9th c. BC, and the location of the Phoenician and Roman port infrastructures remains unknown. Today, the ancient city is located on a promontory in the heart of the Medjerda delta, 10 km inland. This project proposes an interdisciplinary effort to understand the Medjerda delta landscape changes during the Holocene. It starts from an archaeological problem and proposes the contribution of geoarchaeology to the understanding of the relationship between ancient societies and their environment. The fluvial palaeoenvironments and sedimentary processes are studied through the mechanical extraction of cores (15-20 m deep) to reach the early Holocene. Selected sediment samples are then studied in laboratory, using different and complementary approaches. First results permitted to draw an hypothesis of the coastline during Antiquity and to bring out the evidence of an intense sedimentation event post 10th c. BC. The location of port infrastructures will bring initial answers to the question of the foundation of the city. The study of river palaeoenvironments of the Medjerda delta during the Holocene aim at a better understanding of the nature of the settlement, as well as the function of the city of Utica over time. This study will also assess the impact of the ancient city on the environment and understand how the city adapted to the mobility of this Mediterranean delta. Furthermore, the analysis of sedimentary processes causing the filling of the harbour basin will lead to speculation about the causes of the abandonment of the structures and more generally the decline of the city in favor of Carthage. It will also examine whether natural or anthropogenic factors have influenced this deltaic progradation over the centuries