Paleobathymetry of foraminiferal assemblages from the Pliocene of the Western Sahel (North-Algeria)

The assessment of paleobathymetry is essential in paleogeographic reconstructions, and generally relies on the extrapolation of the depth distribution of modern taxa to fossil forms. Methods to estimate paleobathymetry take into account the depth range in which individual taxa have been encountered or parameters related to the depth variations found on present day bathymetric transects, as the planktic/benthic (P/B) ratio. This study presents a quantitative analysis of paleobathymetry of foraminiferal assemblages from the Pliocene of Western Sahel, complementing previous paleobathymetric reconstructions based on semi-quantitative data from macrofaunal taxa. The foraminiferal assemblages are assessed through correspondence analysis and resulting sample scores are plotted according to the main variability factor which is interpreted to reflect paleobathymetry. The calibration of the scores in terms of water depth allows a detailed bathymetric interpretation of the obtained curve. The validity of reconstructed paleodepths is tested against the bathymetries calculated from the P/B ratio.