Two examples ofalbite-rich granitoids of different genesis are discussed: the Ta-Li granite at Yichun (China) exhibits dominantly igneous textures, and the sodium-enrichment zone in biotite granite of the Sn-W deposit at Tikus is characterized by metasomatic textures. The Yichun stock shows a magmatic evolution from biotite-muscovite granite to lepidolite granite with an increase of Na20 and F concentrations and a decrease of CaO and Sr concentrations. The composition of the different granite phases is close to pseudoternary minima in the haplogranite-H20(-Li-F) system. The composition of the F-rich albitization zone at Tikus deviates strongly from the pseudoternary minima and shows a tendency to become monomineralic (nearly pure albitite). CaO and Sr concentrations are increased or remain unchanged with respect to the unaltered biotite granite at Tikus. Albitization produced by fluid-rock interaction in F-rich systems is characterized by that CaO or Sr released by the breakdown of plagioclase in the granite protolith, are fixed in newly formed fluorite or albite, respectively. aluminous granitoids) as well as REE, Y, Nb and Zr (peralkaline granitoids).Apart from textural studies, the geochemical characterization of the granitoids is crucial for distinguishing sodium-enrichment in the magmatic stage from metasomatic sodium-enrichment. This can be demonstrated with two examples: the rare-metal granite at Yichun (China) crystallized from a sodium-rich magma, and the albitized granite associated with Sn-W greisen at Tikus (Indonesia) which is an example of albite deposition by the interaction of sodium-bearing fluids within a consolidated granite along a tectonized zone.
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