Mineralogical characterization and mapping using reflectance spectroscopy: an experiment at Alto do Giz pegmatite in the south portion of Borborema pegmatite Province (BPP) Northeastern Brazil

Resumo

Field and laboratory refl ectance spectroscopy measurements made possible the characterization of kaolinite, muscovite, lepidolite, Na_muscovites, cookeite and tourmaline. Mixtures and spatial distribution of these minerals, together with quartz, spodumene, tantalite, euclase and garnet, were used to defi ne internal zonation of the Alto do Giz pegmatite. The co-occurrence of Lithium-bearing minerals in the border zone of N2 and N3 quartz cores was key in defi ning the Zone III (inner zone). The inner zone had not been done previously in this pegmatite, due to the intense kaolinization overprinting the rock bulk mineralogy. It is demonstrated that refl ectance spectroscopy is a useful tool for mineralogical studies, even in earlier fi eld works, contributing to sample and map pegmatites of Borborema Pegmatitic Province.