Shelf inhabiting foraminifera as a tool for understanding late quaternary mass transport processes in the Northern Gulf of Eilat/Aqaba, Red Sea

Sedimentary systems on continental margins are sensitive to climate change and sea level fluctuations, especially in tectonically active areas as the Gulf of Eilat/Aqaba (GEA). During the Late Quaternary, in addition to the repetitive seismic activity along the Dead Sea Transform, drastic changes in sea level, temperature and salinity occurred in the marine environment resulting in changes of the faunal community. In this study, a newly established approach, using the depth distribution of foraminifera to identify displaced sediment units, is utilized to reconstruct the events, which occurred in this rapidly changing environment. A total of 11 units of displaced sediments and 3 temporally significant unconformities were identified based on foraminiferal assemblages and time constrained by radiocarbon dating. These were identified within two cores from the GEA northwestern slope at water depth of 300–400 m, covering up to 40 kyr BP. Two foraminiferal assemblages were identified corresponding with the changing salinity: 1) the ‘Holocene assemblage’ dominated by the stenohaline symbiont-bearing larger species Operculina ammonoides, Amphistegina papillosa and Amphistegina bicirculata; and 2) the ‘Glacial assemblage’ dominated by the hypersaline tolerant species Elphidium cf. limbatum, Elphidium jenseni and Peneroplis planatus. Both assemblages were found in deeper settings than their natural living habitat, indicating the presence of sediment transport down slope, and suggesting benthic foraminifera can serve as an indicator for sediment transport events. Unconformities were found to be associated with periods of rapid sea level changes and/or increased sedimentation rates, effecting sediment porosity and slope stability. Displaced shells of the ‘Holocene assemblage’ were dated to 12 kyr BP and believed to be the first recorded evidence for the post glacial re-settlement of this ecologically important group in the northern GEA.