Geochemical and statistical characterization of the phosphate facies of the F arim‐ S aliquinhé phosphate mineralization ( G uinea‐ B issau)

The E ocene F arim‐ S aliquinhé phosphate mineralization ( FSPM ) is a buried sedimentary deposit located in the northern part of G uinea‐ B issau, discovered and spatially constrained during the 1980s by the F rench G eological S urvey ( BRGM ). In the present work some of the data collected at that time are reworked in the framework of the development of a 3D geological and geochemical model of this mineralization. We show the usefulness of two classical multivariate statistical methods – principal component analysis ( PCA ) and cluster analysis ( CA ) – applied to eight geochemical variables ( P 2 O 5 , SiO 2 , Al 2 O 3 , Fe 2 O 3 , CaO , MgO , F and CO 2 ) measured in 247 samples from phosphate facies, for differentiation of samples taken from the different phosphate facies recognized in the FSPM , namely the main ore FPA (30 to 35% high grade phosphate), the calcareous low grade phosphate FPB (10 to 20% P 2 O 5 ) (both L utetian), and a mineralized Upper E ocene to Lower O ligocene cover (mainly including the FPO level and a silico‐aluminous phosphate bed), overlying the FPA , which can also be considered a third set of phosphate facies associated with the FSPM .