Facies and fauna proxies used to reconstruct the MIS 5 and MIS 7 coastal environments in eastern Tunisia

Abstract

This study is based on the analysis of the sedimentology and the fossil assemblages of Pleistocene deposits in Eastern Tunisia. It uses different fauna assemblages to help infer palaeoenvironments and in particular discusses the importance of the distribution of Persististrombus fetus, especially as regards MIS 5e deposits around the Mediterranean Basin. The strati graphic succession has been divided into two main units. The lower unit is quartz-rich. Its basal part contains a marine fauna that includes well-preserved bivalves, gastropods, echinoids and cirripedes dominated by Acanthocardia, Cerastoderma, Parvicardium, Arca, Donax, Glycymeris, Loripes, Tellina and Cerithium. This fauna represents a typical association/biocenosis typically developed in a sheltered bay, of moderate to low wave/current action and rapid post-mortem burial. The upper unit is carbonate-dominated. Its basal part also contains a rich marine fauna that includes the extant tropical West African species Persististrombus fetus. The occurrence of Persististrombus fetus in this unit compared to its presence in the whole Mediterranean basin in the Late Pleistocene leads us to question its importance in the interpretation of climate warming during the Late Pleistocene, and to suggest its Atlantic origin.