Mineralogy, geochemistry and origin of the phosphorites at ... Springer
The most important factors control the mineral composition of the phosphate rocks is type and source. They are classified into four groups. They are sedimentary marine origin (75%), igneous origin (1520%), metamorphic and weathered origin (8%), and 23% as biogenic sources (Ozer et al. 2000).Silica, clayey and calcareous materials are gangue minerals for the sedimentary phosphate origin.