What are three forms of inorganic phosphate making up geological reservoir?

Answer 1

Occurrence

Phosphate rock occurs in three forms: as guano; as igneous rock containing a high content of apatite; and as sedimentary phosphorites, which now provide by far the greatest part of world supply.

Sedimentary phosphorites formed from time to time during the past 550 million years by chemical precipitation, epigenetic replacement, or biogenic concentration. Phosphorite is particularly common in Cretaceous to Miocene rocks as a result of the accumulation of fish and other organic debris, on areas of the sea bed where deep upwelling ocean currents carried nutrients and supported a rich marine life. Such deposits may be enriched by reworking, before being covered, compacted, and uplifted by normal sedimentary and structural processes. The phosphorite content of the beds may also be raised further by near-surface leaching and enrichment. Sedimentary phosphate rock that is mined generally has a P2O5 content greater than 20 percent.

Guano concentrations, on small oceanic islands, are fossil deposits resulting from an extension of the organic cycle. Sea birds feeding on the rich marine life rested on small limestone islands. With low rainfall, their excreta built up on and interacted with the limestone to form phosphorous compounds. Resources are now almost exhausted.

Igneous deposits of phosphate rock are related chiefly to alkaline intrusive bodies, and generally grade less than 20 percent, in some cases under 5 percent, P2O5. The apatite is commonly associated with other recoverable industrial minerals such as nepheline, mica, and calcite. In Sweden phosphorous is recovered from high‑phosphorous iron ore.

Answer 2

The three forms of inorganic phosphate making up geological reservoirs are calcium phosphate minerals (e.g., apatite), iron phosphate minerals (e.g., vivianite), and aluminum phosphate minerals (e.g., wavellite). These minerals play a vital role in the global phosphorus cycle, acting as reservoirs that release phosphate over geologic timescales.

Answer 3

no