Research press release


Scientific Reports

Geoscience: Unravelling the complex history of the lost harbour of Pisa



今回、David Kaniewskiたちの研究グループは、長期的な沿岸動態と海水面上昇、および環境変化がポルトゥス・ピサヌスの発展において果たした役割を解明するために、リグリア海東部の1万500年間にわたる相対的な海水準の推移を再現した。また、各時代の地図と地質学的データを組み合わせることで、ピサのポルトゥス・ピサヌス港周辺の海岸の形状の推移を再現した。そして、堆積層から採集された生物試料を分析して、海水や淡水、農業活動がこの地域の環境にどのような影響を及ぼしたのかを調べた上で、文献や考古学的データと照合した。


New insights into the evolution and eventual disappearance of Portus Pisanus, the lost harbour of Pisa, are reported in Scientific Reports this week.

Although it has been described as one of Italy’s most influential seaports during the Roman and Middle Ages, little is known about the relationship between Portus Pisanus’s environment and the main stages of its history.

To understand the role that long-term coastal dynamics, sea-level rise and a changing environment played in the harbour’s evolution, David Kaniewski and colleagues reconstructed relative sea levels for the eastern Ligurian Sea over a 10,500-year period. They also coupled historical maps with geological data to reconstruct the morphology of the coast around the Pisa harbour basin. They analysed biological samples from sediment layers to investigate how seawater, freshwater or agricultural activities may have influenced the environment in the area, before comparing and contrasting their data with written sources and archaeological data.

The findings suggest that at approximately 200 BC, a naturally protected lagoon with a good connection to the sea developed south of the city of Pisa that would have benefited navigation and trade, and facilitated the establishment of port complexes. The lagoon hosted Portus Pisanus well beyond the 5th century AD but its degree of sea connection began to decline from around 1000-1250 AD, as coastlines shifted towards the sea. It was cut off from the sea and disappeared around 1500 AD when the basin developed into a coastal lake and Portus Pisanus was replaced by the maritime harbour of Livorno.

doi: 10.1038/s41598-018-29890-w


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