Microthermometric study of fluid inclusions in Neogene shallow intrusions from the Inner Carpathian arc (Romania)

Fluid inclusions have been observed in quartz phenocrystals of the most acid facies (rhyolite and dacite) of the subvolcanic area (Rodna-Bargau Mountains) in the East Carpathians. All identified fluid inclusions are aqueous (H2O–NaCl system). They occur either as primary or pseudosecondary and secondary fluid inclusions. Homogenisation, both to liquid and vapor, occurs between 120 and 540 jC. The general evolution of aqueous fluids is to decreasing salinity with decreasing temperature. Relatively low salinities (from 6 to 1.4 wt.% NaCl eq.) could indicate the presence of meteoric water. The occurrence of exploded fluid inclusions indicates strong decompression regime during magma uplift.