Portus, the maritime harbor of Rome at the height of the Roman Empire, was a port complex composed of basins and canals connecting the commercial harbor to the city via the Tiber River. Now, an international team of archaeologists and geologists has applied marine geology techniques at the archaeological site to uncover harbor technologies of the first centuries CE.
Portus was established in the middle of the first century CE and for well over 400 years was Rome’s gateway to the Mediterranean.
It was centered around a large hexagonal basin, which can still be found today near Rome’s Fiumicino airport.
The port played a key role in funneling imports to the citizens of Rome from across the region and beyond.
“Dating ancient harbor sediments is a major challenge, given ports are not only subjected to weather events throughout history, but the lasting effects of human activity,” said Dr. Agathe Lisé-Pronovost, an archaeology research fellow and a marine geologist at La Trobe University.
In order to overcome the problems of dating harbor deposits, Dr. Lisé-Pronovost and colleagues used a range of high-resolution sediment analyses including piston coring, X-ray scanning, radiocarbon dating.
These methods allowed precise identification of major reworked events, including dredged and hyperpycnal deposits.
“Ancient harbors can accumulate sediments more rapidly than natural environments, which is the case of Portus built in a river delta and where sediment accumulated at a rate of about one meter per century,” Dr. Lisé-Pronovost said.
“Applying these methods allowed us to date and precisely reconstruct the sequence of events of the historical port, including dredging to maintain enough draught and canal gate use.”
“The findings suggest that the Romans were proactively managing their river systems from earlier than previously thought — as early as the 2nd century CE.”
The team’s paper was published in the March 2019 issue of the journal Quaternary International.
A. Lisé-Pronovost et al. 2019. Dredging and canal gate technologies in Portus, the ancient harbour of Rome, reconstructed from event stratigraphy and multi-proxy sediment analysis. Quaternary International 511: 78-93; doi: 10.1016/j.quaint.2018.05.018