Abstract
Tin deposits in Eastern Marche (French Massif Central) and North of Viseu (Portugal) are associated with final stages of differentiation of granitoid magmatism. Fractional crystallization causes increase in Sn, W, Ta, Rb, Cs, F and Li, and decrease in Ti, La, U, Th, Ba etc. That trend is very clearly expressed by tantalum, strongly correlated with tin, and by titanium. Hence the TiO2/Ta ratio is a good indicator of granitic melt differentiation. Its value gradually ranges from 4 900 in the less differentiated granodiorite to <1 in the most differentiated granite from Marche area. That ratio could be a useful guide to suitable areas for tin exploration.
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Boissavy-Vinau, M., Roger, G. The TiO2/Ta ratio as an indicator of the degree of differentiation of tin granites. Mineral. Deposita 15, 231–236 (1980). https://doi.org/10.1007/BF00206516
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DOI: https://doi.org/10.1007/BF00206516