Recent and Late Quaternary shelf phosphorites have low Fe, Ti and Al contents. These elements enter the phosphorites with terrigenous impurities and organic detritus. Ti, Al, and some Fe are removed when the phosphorites are lithified, whereas remaining iron settles in the phosphorites as sulfides. Ti/Fe, Al/Fe and Ti/Al ratios are used as examples of difference between behavior of Fe and that of Ti and Al.
Supplement to: Tambiev, Sergey B (1978): Behavior of iron, titanium and aluminum in the initial stages of formation of oceanic phosphorites. Oceanology, 18(3), 327-330