Late Holocene paleoclimatic reconstruction inferred from El Bibane lagoon in southeast Tunisia - Normandie Université Accéder directement au contenu
Article Dans Une Revue Journal of African Earth Sciences Année : 2023

Late Holocene paleoclimatic reconstruction inferred from El Bibane lagoon in southeast Tunisia

Résumé

The reconstruction of paleofloods in the late Holocene has become an important research highlight in the context of the present climate change. The Tunisian Mediterranean coast is a region that is prone to experiencing severe weather. The flood events have a significant impact on the infrastructure and populations residing in coastal lowlands. Studies on lagoon sediments have recently revealed important information about the past extreme hydrological events as well as their relationship with past climate changes. This study aims to reconstruct the historical extreme flood-event record using sediment cores taken from the El Bibane coastal lagoon, southeast of Tunisia. Three sediment cores BL12–5, BL12–7 and BL12–10 were studied. Through a combination of analytical techniques such as the chronological, geochemical and sedimentological analyses, past flash floods were identified. Results display that the sedimentological signature of the paleoflood levels recognized within the lagoonal sequence is characterized by high values of the elemental ratios (Ti/Ca and Fe/Ca) and high content of fine material such as clay and silt. These floods are thought to have occurred as a result of intense precipitation that increased the terrigenous input to the El Bibane lagoon by the Fessi River. Chronologies of 210Pb, 137Cs, and 14C have been used to calculate the age of these floods. The records offer a good temporal correlation with historical floods recorded in the central Mediterranean region. In the southeast of Tunisia, periods with more frequent floods coincide with periods generally under alternation of wetter and drier conditions and minima of solar activity. The paleoflood record of the El Bibane lagoon can help researchers better understand the physical mechanisms responsible for changes in the intensity and/or frequency of extreme events in the south of Tunisia. Our research proves that the proxies utilized here have a lot of potential for reconstructing past floods, which is important knowledge for future flood prediction and mitigation in southeast Tunisia.
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Dates et versions

hal-04419144 , version 1 (26-01-2024)

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Aida Affouri, Soumaya Boussetta, Laurent Dezileau, Nejib Kallel. Late Holocene paleoclimatic reconstruction inferred from El Bibane lagoon in southeast Tunisia. Journal of African Earth Sciences, 2023, 204, pp.104961. ⟨10.1016/j.jafrearsci.2023.104961⟩. ⟨hal-04419144⟩
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