Epi-bathyal ostracod assemblage in Holocene Rhone deltaic sediments (Gulf of Lions, NW Mediterranean) and their palaeoecological implications

Autor: Fanget, A.-S., Bassetti, M.-A., Berné, S., Arnaud, M.
Přispěvatelé: Institut de Radioprotection et de Sûreté Nucléaire (IRSN)
Jazyk: angličtina
Rok vydání: 2013
Předmět:
Zdroj: Revue de Paléobiologie
Revue de Paléobiologie, Museum d'Histoire Naturelle de la Ville de Geneve, 2013, 32 (2), pp.589-606
ISSN: 0253-6730
1661-5468
Popis: International audience; Since the Last Glacial Maximum, the Rhone River, which is the most important source of freshwater and sediment to the western Mediterranean Sea, migrated in a north-westward direction during the rapid Deglacial and Early Holocene sea-level rise. During the phase of global high sea-level (Middle and Late Holocene), an overall eastward migration of the Rhone outlet, under natural and/or human influence, is recorded through several sediment accumulations confined along the inner shelf in the form of deltaic lobes. These lobes that make up the whole Rhone subaqueous delta represent very expanded sedimentary archives of the Rhone Holocene history. In this paper, using three long piston cores retrieved from the most recent Bras de Fer (RHS-KS55) and Roustan (RHS-KS22 and RHS-KS57) deltaic lobes, at water depth ranging from 43 m to 79 m, we analyze the distribution of the Rhone ostracod assemblages during the Holocene. Our study highlighted the presence of epi-bathyal ostracods belonging to the genus Argilloecia, Cytheropteron and Krithe in shallow water deltaic sediments. Close to the Rhone River mouth, the presence of these full-marine ostracods is limited because of well-marked fluvial influence, whereas the occurrence of Argilloecia spp., C. rotundatum, K. compressa and K. pernoides increases with increasing distance from the river mouth. Thus, we hypothesize that C. rotundatum, K. compressa, and especially Argilloecia spp. might be more tolerant to higher fluvial influence than K. pernoides, which is only observed in the distal part of the Rhone River influence. Environment-related parameters (such as fresh-water and sediment input from the Rhone River, food supply, and dissolved oxygen) other than bathymetry are thought to have a major role in the development of these full-marine ostracods at the studied site.
Databáze: OpenAIRE
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