REEs in the North Africa P‐Bearing Deposits, Paleoenvironments, and EconomicPerspectives: AReview

AreviewofthecompositionalfeaturesofTunisia,Algeria,andMoroccophosphoritesisproposedinordertoassessandcomparethepaleoenvironmentalconditionsthatpromotedthede‐positformationaswellasprovideinformationabouttheireconomicperspectiveinlightofgrowingworldwidedemand.Sincethesedepositsshareaverysimilarchemicalandmineralogicalcomposi‐tion,theattentionwasfocusedonthegeochemistryofrareearthelements(REEs)andmostlyonΣREEs,CeandEuanomalies,and(La/Yb)and(La/Gd)normalizedratios.TheREEsdistributionsrevealseveraldifferencesbetweendepositsfromdifferentlocations,suggestingmostlythattheTu‐nisianandAlgerianphosphoritesprobablywerepartofthesamedepositionalsystem.There,sub‐reducingtosub‐oxicconditionsandamajorREEsadsorptionbyearlydiagenesiswererecorded.Conversely,intheMoroccanbasins,sub‐oxictooxicenvironmentsandaminordiageneticalterationoccurred,whichwaslikelyduetoadifferentseawatersupply.Moreover,thedrasticenvironmentalchangesassociatedtothePaleocene–EoceneThermalMaximumeventprobablyinfluencedthecom‐positionofNorthernAfricanphosphoritesthataccumulatedthehighestREEsamountsduringthatspanoftime.BasedontheREEsconcentrations,andconsideringtheoutlookcoefficientofREEcomposition(Koutl)andthepercentageofcriticalelementsin ΣREEs(REEdef),thestudieddepositscanbeconsideredaspromisingtohighlypromisingREEoresandcouldrepresentaprofitableal‐ternativesourceforcriticalREEs.