The environments of the Siculo-Tunisian Strait and paleohydrology of the Mediterranean during the Late Quaternary

• Main Author: Zouari, Sonda
• Other Authors: Géosciences Paris Saclay (GEOPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay, Université de Sfax (Tunisie), Giuseppe Siani, Nejib Kallel
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2021
• Subjects: Siculo-Tunisian strait; Planktonic foraminifera; Carbon-14; Bio-events; Biozone; Residence time; Détroit Siculo-Tunisien; Foraminifères planctoniques; Carbone-14; Bio-évènements; Temps de résidence; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology; [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology
• Online Access: https://theses.hal.science/tel-03327645; https://theses.hal.science/tel-03327645/document; https://theses.hal.science/tel-03327645/file/82723_ZOUARI_2021_archivage.pdf

The aim of this thesis focus on the restitution of the hydrology of intermediate and deep water masses during the last 24 ka in the Mediterranean Sea in the Siculo-Tunisian Strait.We firstly generated high-resolution biochronological records extending from the last glacial period. These records are based on oxygen isotopic analyses, micropaleontology (planktonic foraminifera) and surface water temperature (SST) carried out along 4 deep-sea sediment cores collected in the Siculo-Tunisian Strait, in the Tyrrhenian Sea, in the Ionian Sea and in the Levantine basin respectively. The quantitative distribution of planktonic foraminifers allowed to identify seven biozones based on the appearance and / or disappearance of the main taxa or their peaks of abundance. The abundance records show that the major changes in the planktonic foraminifera assemblages are similar in the central and western basins. Indeed, 4 bioevents have been recognized and can be used as reference markers to establish or improve the chronology of marine sediment cores from the Mediterranean basin.Successively, we have reconstructed changes in the ventilation rate of the intermediate and deep water masses since the last glacial period by measuring the 14C age difference between monospecific species of benthic and planktonic foraminifera (BP) recovered from deep seas cores bathed by intermediate and deep water masses (KET80-37 and REC13-53). The results show that the deposition of the last Sapropel S1 does not require a period of preconditioning, often evoked by climate models to explain the time lag between the beginning of the increase in the Nile river flow and the start of the establishment of S1. Les objectifs de cette thèse se focalisent sur la restitution de l’hydrologie des masses d’eaux intermédiaires et profondes au cours des derniers 24 ka en mer Méditerranée dans le détroit Siculo-Tunisien.Nous avons généré, dans un premier temps, des enregistrements biochronologiques à haute résolution s’étendant depuis la dernière période glaciaire. ...