The moderate to strong positive correlation between Ba and [P.sub.2][O.sub.5] (r = 0.83) and between Ba and REEs (r > 0.7) may provide reason for the presence of the Al-bearing secondary phosphates like gorceixite
[Ba[Al.sub.3][(LREE, P[O.sub.4]).sub.2][(OH).sub.5].[H.sub.2]O] (Costa and Araujo, 1996) that was not detected by XRD analysis.
Rasmussen, "Early-diagenetic REE-phosphate minerals (florencite, gorceixite
, crandallite, and xenotime) in marine sandstones: a major sink for oceanic phosphorus," American Journal of Science, vol.
Goldbery and Loughnan (1977) report the occurrence of dawsonite, alumohydrocalcite, nordstrandite and gorceixite
in Permian marine strata of the Sydney Basin, Australia.
1997, (= magnetite + chromite) 163 Ferrazite (= gorceixite
) Atencio and Clark: Min.