Regularities in the distribution and genetic features of phosphate ore deposits

The analysis of geotectonic settings and the planetary distribution of phos phate ores revealed that apatite deposits are confined to the continental r ift zones with the uplifted Moho discontinuity, while phosphorite deposits are developed on ancient continental shelves, which mark upwelling zones in the paleooceans that received phosphorus during the oceanic crustal spread ing. It is established that the formation of economic phosphate deposits in the Panerozoic corresponds to epochs of intense planetary tectonic and vol canic activity, which also emphasizes the substantial role of endogenic pho sphorus in phosphorite accumulation. It is shown that the accumulation of p hosphate ores on continents and in oceans was synchronous. Large phosphorit e reserves accumulated during particular epochs correspond to insignificant apatite ore reserves and vice versa.