Infrared spectra study of the Moslavacka Gora (Croatia) tourmalines O-H stretching region: Inference of fluid involvement in the late cretaceous igneous evolution of a complex Adria-Europe convergence zone

Infrared spectra (IR) in the O-H stretching region were recorded for natural tourmalines from magmatic and magmatic-hydrothermal systems of Moslavacka Gora (Croatia). Samples disseminated tourmaline (schorl) representing products collected leucogranite. Nodular (intermediate members schorl-dravite series) twomica granite represents a mineral related to final stage crystallization. IR typically show four sharp bands: 3643, 3633, 3550, 3484 cm?1, while typical nodular shows with asymmetric relatively broad bands on 3635 3554 cm?1 shoulders at higher lower wavenumber side. The broadening compared indicates water content type. At same time, observed shifts between corresponding can be explained by shortening O-H1 O-H3 distances, which attributed different genetic and/or evolutionary processes. According models applicable Gora, leucogranite considered (pegmatitic) product standard accessory phase origin tourmaline, was last crystallize evolved Late Cretaceous granitic system is interaction fluid residual melt originating wall-rock low-pressure crustal setting, accompanied rapid cooling. This resulted an increased dravite reflected spectral features.