Benthic foraminiferal paleoecology of the Maastrichtian succession at the Kharga Oasis, Western Desert, Egypt

Abstract

The present work deals with the benthic foraminiferal investigations and analyses of the Maastrichtian succession from two sections in the Kharga Oasis (Naqb El-Rufuf and Gabal Teir), to evaluate the prevailing paleobathymetric and paleoenvironmental conditions. Three benthic foraminiferal assemblages have been distinguished by the R-mode cluster analysis. The first two clusters are dominated by simple-walled and complex-walled non-calcareous agglutinated foraminifera, respectively; while the third assemblage is characterized by calcareous agglutinated and calcareous benthic foraminiferal species. The Q-mode Detrended Correspondence Analysis (DCA) of the studied samples indicates five main groups designated as five biofacies (IV), each with a characteristic faunal structure. The overall dominance of the non-calcareous agglutinated foraminifera and the sporadic occurrence of the calcareous benthic foraminifera suggest deposition in a shallow water environment of restricted brackish, lagoonal, and littoral setting with occasional marine incursions. The distribution of the identified benthic foraminiferal species suggests deposition under oxygen-depleted conditions with high organic matter flux. Surficial epifaunal taxa dominate the benthic assemblages at certain intervals suggesting episodes of stagnation and elevated position of the redox boundary relative to the water/sediment interface.