Eppawala phosphate deposit mineralogy: weathering origins of carbonatite apatite?

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Ines920 rep

What geochemical conditions during the Proterozoic created the unique high-grade chlorapatite and hydroxyapatite carbonatite complex mined at Eppawala in Anuradhapura?

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The Eppawala phosphate deposit represents a deeply weathered Proterozoic carbonatite body intruded into the Precambrian high-grade metamorphic basement of the Wanni Complex. The parent carbonatite rock consists of calcite and dolomite matrix hosting rich disseminations of coarse, euhedral fluor-chlorapatite crystals. Over hundreds of millions of years, intense tropical chemical weathering leached the soluble carbonate minerals, leaving behind an insoluble residual leached mantle highly enriched in secondary phosphate crystals, martite, and magnetite.

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Bandula GSMB1760 rep

Visiting the operational open-cast quarry pits requires prior clearance and hardhat permits from Lanka Phosphate Limited.

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Ines920 rep

The residual apatite crystals frequently display vibrant green, amber, and honey-yellow hexagonal prism terminations prized by structural mineral collectors.

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Pradeep1640 rep

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