The lake of Tunis, located in northern Tunisia, is part of the coastal wetlands sensitive to climatic and anthropic variations. This fragile ecosystem was an open bay 190 ka BP ago. Today, it is separated from the Mediterranean by a sandy barrier fed mainly by the Madjerda wadi. This study, based on a multidisciplinary geological approach, examines the evolution of the dynamics of the Tunis Lake, as well as the recent environmental changes that control the sedimentation. Two cores LN1 (55 m) and LS1 (40 m) were collected in the alluvial deposits, respectively in the North-East and South-East of the Lake. These cores have been studied in detail to determine the spatio-temporal distribution of the sedimentary stock. The data from this study complemented by those from previous work allowed us to refine and establish spatio-temporal correlation scenarios of the sediments filling the Tunis lagoon. These correlations are established between the LN1 core and the core taken at the SE (LS1). Spatial and temporal monitoring of sediment deposition in these cores has revealed a general regressive evolutionary trend, from a frankly marine environment to a lagoon environment more or less communicating with the sea, from the Middle Pleistocene (an age between 159 and 205 ka) to the present Holocene. The identification of ostracod associations typical of open marine or lagoon environments and of benthic foraminifera associations of lagoon environments has allowed us to trace the history of the Tunis Lake over the last two millennia. It begins with an open marine environment (around 2030 years BP) followed by an open lagoon environment around 1700 years BP.

Evolution des environnements de la Lagune de Tunis du Pléistocène moyen à l’Holocène [Middle Pleistocene-Holocene environmental evolution of the Tunis lagoon]

SCIUTO F.
2023-01-01

Abstract

The lake of Tunis, located in northern Tunisia, is part of the coastal wetlands sensitive to climatic and anthropic variations. This fragile ecosystem was an open bay 190 ka BP ago. Today, it is separated from the Mediterranean by a sandy barrier fed mainly by the Madjerda wadi. This study, based on a multidisciplinary geological approach, examines the evolution of the dynamics of the Tunis Lake, as well as the recent environmental changes that control the sedimentation. Two cores LN1 (55 m) and LS1 (40 m) were collected in the alluvial deposits, respectively in the North-East and South-East of the Lake. These cores have been studied in detail to determine the spatio-temporal distribution of the sedimentary stock. The data from this study complemented by those from previous work allowed us to refine and establish spatio-temporal correlation scenarios of the sediments filling the Tunis lagoon. These correlations are established between the LN1 core and the core taken at the SE (LS1). Spatial and temporal monitoring of sediment deposition in these cores has revealed a general regressive evolutionary trend, from a frankly marine environment to a lagoon environment more or less communicating with the sea, from the Middle Pleistocene (an age between 159 and 205 ka) to the present Holocene. The identification of ostracod associations typical of open marine or lagoon environments and of benthic foraminifera associations of lagoon environments has allowed us to trace the history of the Tunis Lake over the last two millennia. It begins with an open marine environment (around 2030 years BP) followed by an open lagoon environment around 1700 years BP.
2023
La Lagune de Tunis, située dans la partie septentrionale de la Tunisie, fait partie des zones humides côtières sensibles aux variations climatiques et anthropiques. Cet écosystème fragile était une baie ouverte il y a 190 ka BP. Aujourd’hui, il est séparé de la Mer Méditerranée par un cordon littoral sableux alimenté essentiellement par l’Oued Madjerda. Cette étude, basée sur une approche géologique multidisciplinaire, se propose d’examiner l’évolution de la dynamique du Lac de Tunis, ainsi que les changements environnementaux récents qui contrôlent la sédimentation. Deux carottes LN1 (55 m) et LS1 (40 m) ont été prélevées dans les dépôts alluviaux, respectivement au Nord-Est et au Sud-Est du Lac. Ces carottes ont fait l’objet d’une étude détaillée qui a permis de suivre la répartition spatio-temporelle du stock sédimentaire. Les données de cette étude, complétées par celles des travaux antérieurs, ont permis d’affiner et d’établir des esquisses de corrélations spatio-temporelles des sédiments comblant la lagune de Tunis. Ces corrélations sont établies entre la carotte LN1 et la carotte prélevée au SE (LS1). Le suivi spatio-temporel des dépôts des sédiments de ces carottes a permis de mettre en évidence une tendance d’évolution générale régressive, allant d’un milieu franchement marin vers un milieu lagunaire parfois communiquant avec la mer, en allant du Pléistocène moyen (un âge compris entre 159 et 205 ka) vers l’Holocène-Actuel. L’identification des associations d’ostracodes et de foraminifères benthiques qui évoluent d’environnements marins ouverts à lagunaires a permis de tracer l’histoire de la lagune de Tunis au cours des deux derniers millénaires. Elle débute par un milieu marin ouvert (aux alentours de 2030 ans BP) suivi par un milieu lagunaire ouvert vers 1700 ans BP.
Environnemental evolution; Holocene; Macrofauna; Microfauna; Pleistocene; Tunis Lake; U-Th dates
File in questo prodotto:
File Dimensione Formato  
lagune de tunis.pdf

solo gestori archivio

Tipologia: Versione Editoriale (PDF)
Licenza: NON PUBBLICO - Accesso privato/ristretto
Dimensione 5.51 MB
Formato Adobe PDF
5.51 MB Adobe PDF   Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11769/576969
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 0
  • ???jsp.display-item.citation.isi??? 0
social impact