PHOSPHORITE AS AN ORE

Phosphorous is one of the essential nutrients for both plant and animal life. As the human population grows, humankind has become increasingly dependent on the use of manufactured fertilizers, and thus on phosphorous. Sedimentary phosphates account for over 90% of the total mined phosphorous. Like any ore body, economic phosphorites must be highly concentrated and relatively easy to extract. These extra demands make ore-producing phosphorites an important subgroup of phosphorites. 

Very slow deposition rates are necessary to create economic-grade phosphorites. Slansky (1986) estimates sediment accumulation rates of economic-grade phosphorites between 2x10 and 1x10 years per meter of deposit. This slow deposition rate is seen in Permian sediments of the Rocky Mountains where the Phosphoria Formation is about 30 m thick in the most phosphatic zone, whereas the same time period is represented by over 1000 m in non-phosphatic sections of the Permian in the Rocky Mountains. 

---