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Fig. Par60a Variation in Ga- and Ti-concentrations
Ga and Ti are enriched at the same positions in the green rim.
Fig. Par60b Variation in Ta- and Nb-concentrations
The variations of these elements can be correlated with the variations in concentrations of Cu and Mn:
Nb- and Ta-concentrations are enriched in the core and the rim of the tourmaline crystal and they are depleted in the Cu-rich growth zone. The Ta/Nb-ratio changes across the profile with highest Ta/Nb in the copper-rich growth zone of the tourmaline with “neon”-blue color. The ratio reverses in the green rim.
Fig. Par60c Variation in REE-concentrations
REE-concentrations (La, Nd and Ce) are enriched at the transition from the “neon”-blue color zone to the green rim.
Fig. Par60d Variation in Ge- and Sc-concentrations
Ge-concentrations are highest in the transition zone from the “neon”-blue to the green color zoning.
In conclusions, the following typical chemical composition can be found in the “neon”-blue blue color zone in the tourmaline:
Cu-, Bi- and Be-concentrations are enriched and Nb, Ga-, Zn-, Pb- and Mg-concentrations are depleted.
Sr, Ti, Zn, Pb and Mg concentrations along with Fe (not plotted, concentrations see Tab. Par03) are enriched in the green part of the crystal.
The “green” rim is also characterized by an increase in the concentrations of Ti and Ga (Fig. Par60a), Pb (Fig.59d) and Sr (Fig. Par 60b).
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LA-ICP-MS Chemical Analysis Profiles of Paraiba Tourmaline, Batalha Mine
