Post-Mortem Onshore Transportation of Epiphytic Foraminifera: Recent Example from the Tunisian Coastline

Abstract

The barrier-island system that connects Jerba Island to the Tunisian coastline is composed mainly of carbonate bioclastic sands. Well-preserved tests of dead epiphytic foraminifera are abundant on the foreshore and backshore, but they are scattered and poorly preserved on the shoreface, where very fine sand-size eolian quartz, peloids, and broken bioclasts are the main components. The reason for this paradoxical pattern is that most epiphytic foraminifera are very easily removed as suspended load by storm-generated currents and concentrated on beaches, washover fans, and small eolian dunes, kilometers away from their original life environment. Similar bioaccumulations are common in the fossil record and have often been interpreted incorrectly as prolific biocoenoses.