Geoarchaeology of the Ancient Harbour of Utica in a Deltaic Context (2014 and 2015)

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.

Based on this observation, our geoarchaeological research focuses on two main issues:
- Was there a marine environment around the promontory of Utica, which could shelter harbour structures?
- Why the city, formerly a seaport city, is today located 10 km from the coast? Can the wadi be solely responsible of such an important sediment accumulation in a few millennia? Have any natural or anthropogenic factors influenced this deltaic progradation over the centuries?

First results permitted drawing an hypothesis of the coastline during Antiquity to the effect that the Utica promontory was surrounded by the sea in an earlier era.
(1) Effectively, the «North compartment» of the delta was covered by the sea at a given time, which will be determined by the next radiocarbon dating. But the sea still brushed the north side of the promontory during the Roman period, as evidenced by the potsherds found in one of the cores. This deep marine bay could be a potential location for harbour infrastructure prior to clogging of the bay by the sediments carried by the wadi.
(2) The «corridor» area, materialised by the promontories of Utica and Kalâat el-Andalous, was also invaded by the sea at one time. The many artifacts found in this core attest the occupation of this area, outside of the maximal extension of the ancient city according to A. Lézine.

Dating of the marine units in the two cores will bring essential data:
* to establish the chronological framework of the retreat of the coastline and of the clogging of the bay;
* to understand the passage of the Medjerda into the «North compartment» by the corridor Utica-Kalâat.

The geoarchaeological results corroborate ancient sources. Utica was able to welcome important harbour structures, since the presence of a deep marine environment is attested around the promontory, but these remains are probably 5 m deep under the alluvium of the Wadi Medjerda.