Evidence for an early land use in the Rhone delta (Mediterranean France) as recorded by late Holocene fluvial paleoenvironments (1640-100 BC)

The overall objective of this paper is to describe the late Holocene (1640- 100 BC) sedimentary and biological evolution of the Rhone-delta-plain, to i nterpret the sedimentary facies and palynofacies as the result of the effec ts of fluvial dynamic fluctuations and relative sea level change and to eva luate the paleohydrological constraints in the development of the land use and settlements of the Camargue. Focus is made on the upper part of V-III c ore drilled on NE of the Vaccares lagoon. By combining sedimentology, palyn ology, magnetic susceptibility and archeological data, this study allowed t o identify the superposition of three types of paleo-environments (marsh, f luvial floodplain, levee/crevasse splay). This sequence indicates a gradual extension of fluvial environments between the end of the second millennium BC and the Ist century BC. The Variability of fluvial dynamic is evident d uring this period with important hood events which contrast with periods of low flow. Pollen record can be a good marker of the fluvial dynamic variab ility. The expression of the riparian tree pollen grains in the coarser flo odplain deposits could correspond to increased fluvial influence and probab ly to erosion of riverbank during flood events. The local plants are associ ated to the low energy sedimentary environments. Focuses are made on the re lations between the evolution of the environment and land use. The developm ent of the cereal culture in the floodplain of the Rhone delta has been dem onstrated between 1640-1410 and 100 BC. The last alluviation of the Rhone p erturbs the research of the archaeological sites in the central part of the delta but the existence of the rural villages from the first part of the f irst millennium BC is highly possible. (C) 2000 Editions scientifiques et m edicales Elsevier SAS.