Correlation Between Phosphate Content and the Foraminiferal Plankton/benthos Ratio in Chalks (late Cretaceous, Northern Israel): Paleoenvironmental Significance?

TLDR: In this paper, the relationship between phosphate content and the foraminiferal plankton/benthos (P/B) ratio in Senonian-Maastrichtian chalks of Galilee, Northern Israel was investigated.

Abstract: SUMMARY Two environments of phosphate deposition within carbonate rocks are distinguished on the basis of the relationship between phosphate content and the foraminiferal plankton/benthos (P/B) ratio in Senonian-Maastrichtian chalks of Galilee, Northern Israel: (1) A normal marine environment of phosphate deposition during Santonian time. This environment is characterized by a low, normal P2O5 content and a positive correlation between P/B ratio and P2O5. Since it is assumed that the P/B ratio increases with the depth of the sea, it is suggested that the phosphate content in carbonate rocks can be employed as a bathymetric indicator. (2) An “abnormal” high phosphate deposition environment, found mainly in Upper Campanian sediments and related genetically to the economic phosphorite deposits in the Negev (Central Israel). The negative correlation of P/B ratio to P2O5 is caused by a shallowing of the sea and a continuous increase in P2O5, (e.g., by upwelling currents or a terrigenous supply) throughout the Upper Campanian.