Articles | Volume 12, issue 7
Clim. Past, 12, 1539–1553, 2016

Special issue: Human–land–sea interactions in the Mediterranean...

Clim. Past, 12, 1539–1553, 2016

Research article 15 Jul 2016

Research article | 15 Jul 2016

Holocene hydrological changes in the Rhône River (NW Mediterranean) as recorded in the marine mud belt

Maria-Angela Bassetti1, Serge Berné1, Marie-Alexandrine Sicre2, Bernard Dennielou3, Yoann Alonso1, Roselyne Buscail1, Bassem Jalali4, Bertil Hebert1, and Christophe Menniti1 Maria-Angela Bassetti et al.
  • 1CEFREM UMR5110 CNRS, Université de Perpignan Via Domitia, Perpignan, France
  • 2Sorbonne Universités (UPMC, Université Paris 06)-CNRS-IRD-MNHN, LOCEAN Laboratory, 4 place Jussieu, 75005 Paris, France
  • 3IFREMER, Centre de Brest, Plouzané, France
  • 4GEOGLOB, Université de Sfax, Sfax, Tunisia

Abstract. Expanded marine Holocene archives are relatively scarce in the Mediterranean Sea because most of the sediments were trapped in catchment areas during this period. Mud belts are the most suitable targets to access expanded Holocene records. These sedimentary bodies represent excellent archives for the study of sea–land interactions and notably the impact of the hydrological activity on sediment accumulation. We retrieved a 7.2 m long sediment core from the Rhône mud belt in the Gulf of Lions in an area where the average accumulation rate is ca. 0.70 m 1000 yr−1. This core thus provides a continuous and high-resolution record of the last 10 ka cal BP. A multiproxy dataset (XRF core scan, 14C dates, grain size and organic-matter analysis) combined with seismic stratigraphic analysis was used to document decadal to centennial changes in the Rhône hydrological activity. Our results show that (1) the early Holocene was characterized by high sediment delivery likely indicative of local intense (but short-duration) rainfall events, (2) important sediment delivery around 7 ka cal BP presumably related to increased river flux, (3) a progressive increase in continental/marine input during the mid-Holocene despite increased distance from river outlets due to sea-level rise possibly related to higher atmospheric humidity caused by the southward migration of the storm tracks in the North Atlantic, (4) multidecadal to centennial humid events took place in the late Holocene. Some of these events correspond to the cold periods identified in the North Atlantic (Little Ice Age, LIA; Dark Ages Cold Period) and also coincide with time intervals of major floods in the northern Alps. Other humid events are also observed during relatively warm periods (Roman Humid Period and Medieval Climate Anomaly).

Short summary
This work represents the first attempt to decipher the linkages between rapid climate changes and continental Holocene paleohydrology in the NW Mediterranean shallow marine setting. Between 11 and 4 ka cal BP, terrigenous input increased and reached a maximum at 7 ka cal BP, probably as a result of a humid phase. From ca. 4 ka cal BP to the present, enhanced variability in the land-derived material is possibly due to large-scale atmospheric circulation and rainfall patterns in western Europe.