New REE deposit Shaxiongdong in Central China, part I: Important rock and mineral associations

Geoscience Research Reports 44, 2011 (GRR for 2010), pages 198–204

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Abstract

The REE deposit of Shaxiongdong represents a well-exposed carbonatite-bearing syenite massif which is located in the southern Qinling-Qilian-Kunlun orogenic belt, 250 km south-east of the Xi'an city. The complex includes six varieties of peralkaline syenites and three widespread varieties of calcite-biotite-aegirine-burbankite carbonatite. The carbonatites occur as dykes up to X00 meters long being mostly composed of coarse- grained calcite (> 80 vol. %), aegirine (5-10 vol. %), biotite (5-8 vol. %), burbankite (4-10 vol. %), feldspars (2-8 vol. %), apatite (2-4 vol. %) with many accessory minerals including, ancylite, bastnasite, cordylite, khanneshite and pyrochlore. Syenites consist mainly of K-feldspar, albite, biotite, nepheline, aegirine and accessory minerals such as barite, apatite, pyrochlore, magnetite, ilmenite, zircon, and sulfides.