Reconstitution of paleostorms events about 300 years ago, recorded in a coastal lagoon (Hérault, South of France)
Pierre Blanche is an elongated lagoon of the Aigues-Mortes gulf complex, its south-east boundary constitutes a shore line of 5 km length. This area, submitted to strong marine influence, is very sensitive to hurricane events. This lagoon was recently affected by October 13 2006 storm which occurred in south of France. Its impact on littoral morphology was an inlet creation with a landward sedimentary transport (washover). The aim of this study is to understand if such events could be recorded, in that wetland environment, over the last 300 years. Therefore four short cores (< 1m) along a transect separated by 200 m were collected. Two cores were studied further in details taken far enough from shore line (200 and 400 m) to register only the most powerful hurricanes. For dating these recent sediments, we have crossed radiochronological recording by 137 C s and 210 Pb models with archaeological data of its past catastrophic events. The sedimentary storm recording is characterized by sequences succession with typical facies, grain size and fauna composition (lagoonal and marine species). This succession allowed to characterize three extreme events over the last 300 years which were dated by 210 Pb chronology. By linking to historical data it can be deduced that these events took place in 1742, 1839 and 1893.
HyMeX – Hydrological cycle in the Mediterranean Experiment 2010-2020