Sedimentary Structure Interpretation, Grain Size Analysis, and Stochastic Modeling of P2 O5 Grades of Kef Essennoun Phosphorite Deposit (Northeast Algeria): Implication for Paleogeographic Setting and Paleoprocesses

Abstract

The Kef Essennoun phosphorite (northeast Algeria) is a layer with an average thickness of 35 m, dipping 10–15° southwards and bounded to the west by the Ain Fouris shoal. On the outcrop, the deposit shows internal layering forming large-scale, high-angle cross bedding. In order to investigate the phosphorite depositional and paleogeographic settings, grain size analysis and Sequential Gaussian Simulation of P2 O5 content from 29 drill holes were carried out. Grain size analysis reveals the transport and reworking of phosphates by paleocurrents. The simulation indicates the elongation of the phosphate formation in the direction N63°, parallel to the Ain Fouris shoal. These results are consistent with sedimentological and oceanographic processes involving transport and migration of phosphates as a submarine dune, as well as interaction of the paleocurrents carrying phosphates with the Ain Fouris shoal.