Post-phosphogenesis processes and the natural beneficiation of phosphates: Geochemical evidence from the Moroccan High Atlas phosphate-rich sediments

The Upper Cretaceous-Paleogene sedimentary series of the High Atlas hosts underexplored phosphate-rich sediments and presents an excellent example how complex interactions between various geological processes control accumulation distribution phosphates. Genetically-linked phosphatic lithofacies from this were investigated for their mineralogical geochemical compositions with purpose assessing impact post-phosphogenesis on behavior genetically-linked understanding chemical elements. Sampled horizons five representative sections along Marrakesh borders using optical scanning electron microscopies (OM SEM), X-ray diffraction (XRD), inductively coupled plasma emission spectroscopy (ICP-OES), mass spectrometry (ICP-MS) techniques. Results indicated that studied are composed a mixture non-phosphatic particles in variable proportions depending facies type. However, fraction is dominated by carbonate fluorapatite (CFA), showing average CO32− content 8.40 ± 0.37 wt%. Geochemical results revealed variations composition different phosphate facies. Low-grade pristine sediment (P2O5 < 12%wt.) can be turned effects storms bottom currents into high-grade granular beds containing up to 24 wt% P2O5. This natural enrichment mirrored bulk rock increasing P2O5 concentrations against decreasing detrital phase-associated elements (K, Al, Si, Ti). Among lithofacies, karst-filling show relatively lower uranium cadmium contents as it experienced polyphase evolution, including winnowing, submarine reworking, transport, subaerial weathering, traced some redox-sensitive proxies such cerium uranium. Despite differentiation, apatite resisted changes preserved its original signature, specifically rare earth signal reflects oxic seawater conditions. differentiation modified phosphates through preferential leaching gangue phases (e.g., carbonates). Furthermore, these triggered oxidation organic matter sulfides, removing associated environmental concern, cadmium. Conclusively, combination mechanical winnowing/reworking weathering most effective way beneficiation phosphate, both economically environmentally.