Beryllium mineralization in the Yichun topaz-lepidolite granite, Jiangxi:Associations of beryilium phosphate minerals
2007; Science Press; Linguagem: Inglês
ISSN
2095-8927
Autores Tópico(s)Clay minerals and soil interactions
ResumoThe famous Yichun topaz-leipidolite granite is characterized by its high P_2O_5 contents of average 0.56%.Its whole-rock Be contents are generally higher than 100×10~(-6),the highest reaches 720×10~(-6),indicating this granite belongs to the Be-mineralized granite.Systematic electron-microprobe study was carried out on the heryllophosphates and other associated phosphate minerals in the Yichun topaz-lepidolite granite.Beryllium minerals in the granite include mostly hydroherderite(BeO=15%-16%),and rarely beryllonite,which appear as intergranular accessory minerals in the middle facies of the granite.Coexisting phosphates include fluorapatite,amblygonite and brazilianite,indicating that Be mineralization took place in P_2O_5-saturated melt.Therefore,it is suggested that beryllium speeiation as phosphate rather than silicate in the Yiehun granite is mainly controlled by relatively higher activity of P than that of Si during the crystallization course of this F-rich,peraluminous and perphosphorus granite.Phosphorus is favorable as network-forming cation to combine with Be.inducing crystallization of herderite or bervllonite if Be is available.
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