J. Laborel et al., BIOLOGICAL EVIDENCE OF SEA-LEVEL RISE DURING THE LAST 4500 YEARS ON THE ROCKY COASTS OF CONTINENTAL SOUTHWESTERN FRANCE AND CORSICA, Marine geology, 120(3-4), 1994, pp. 203-223
On the rocky coasts of the northwestern Mediterranean basin, biogenic
littoral rims built by the coralline rhodophyte Lithophyllum lichenoid
es develop, whose remains may be preserved for millennia when submerge
d in a rising sea environment. These remains can be used as biological
indicators of recent sea-level variations. Our survey of the continen
tal coasts of Var and Bouches du Rhone, west of Marseilles (southern F
rance) and of northern Corsica shows that relative sea level rose abou
t 1.6 m in the study area during the last 4500 years without exceeding
the present datum. The rate of sea-level rise was 0.4 mm per year bet
ween 4500 and 1500 yr B.P. and slowed down to 0.2 mm per year from 150
0 yr B.P. to present time. There are also morphological indications of
an acceleration of the rate of sea-level rise during the last century
, supporting the evidence of tide gauges. Regions at the periphery of
the above zone (Alpes Maritimes, Italian border zone, and the French a
nd Spanish Catalonia regions) were also surveyed, but a weaker develop
ment of Lithophyllum rims and bad preservation of algal remains led to
unconvincing dates which could also be linked to regional tectonic tr
ends.