Variation of relative mean sea level during the last 4000 years on the northern shores of Lacydon, the ancient harbour of Marseilles (Chantier J. Verne)

Sediments, archaeological structures and marine paleo-environments unearthed from the northern shore of Lacydon, the ancient harbour of Marseilles, reflect a steady rise of relative sea level (RSL) during the last 4000 years, gradually slowing down to a nearly stable level from about 500 AD on to the last century. This evolution is similar in direction to that previously found along rocky coasts of the same region, but the rise appears to have been more rapid due to local neotectonic action and sediment compaction. No traces era sea level stand above present datum have been found. The 0.10 m rise of MSL, recorded by tide gauges from the end of the 19th century to present times, appears to be a recent acceleration rather than the continuation of a trend.