Raman spectra of water in fluid inclusions: I. Effect of host mineral birefringence on salinity measurement

Abstract

International audienceRaman microspectrometry of water in individual aqueous fluid inclusions can provide chemical information about fluid composition, in particular the concentration of chloride ions. The regular method consists in correlating the deformation of the OH stretching vibration band of liquid water in the region assigned to hydrogen-bonded OH groups with chloride concentration. In the present study, a set of seven different minerals with various birefringence properties (barite, calcite, celestine, fluorite, kyanite, quartz and siderite) was selected for the analysis of the water band of their hosted aqueous fluid inclusions. The comparison with microthermometry highlighted that any birefringent mineral may affect the determination of salinity carried out by the analysis of the Raman signal of water: the Raman salinity exposed sinusoidal variations when rotating the samples on the microscope stage. This phenomenon was explained by mineral birefringence, and by the polarization properties of the OH stretching vibration band of liquid water and of the spectrometers gratings. A good knowledge of the polarization properties of the optical devices of the Raman spectrometer and a correct positioning of the sample thus result in salinity (chloride concentration) measurements with the same accuracy as classic microthermometry

CO 2 flow during orogenic gravitational collapse: Syntectonic decarbonation and fluid mixing at the ductile-brittle transition (Lavrion, Greece)

“…Natural water-rich CO 2 fluid inclusions hosted in Kyanite (Zambia) (H 2 O-CO 2 -NaCl, with T m (car) = -56.6 °C) (Caumon et al, 2015), H 2 O-NaCl and H 2 O-NaOH synthetic fluid inclusions, with respectively T e = -21.2 ° and T m (ice) = -0.4 °C were used to calibrate the analytical device. The following phase transitions were measured when it was possible:…”

Magmatic and hydrothermal behavior of uranium in syntectonic leucogranites: The uranium mineralization associated with the Hercynian Guérande granite (Armorican Massif, France)

“…Salinity is expressed as weight equivalent percent NaCl (wt.% NaCl eq.) and has been calculated using the measured ice melting temperature (Tm Ice) with the equation of Bodnar (1993) and Raman analyses (Caumon et al, 2013(Caumon et al, , 2015.…”

Recent advances in linear and non‐linear Raman spectroscopy. Part X

“…Caumon and co‐workers determined the Raman spectra of water in fluid inclusions to study the effect of host mineral birefringence on salinity measurement. They find that a good knowledge of the polarization properties of the optical devices of the Raman spectrometer and a correct positioning of the sample thus result in salinity (chloride concentration) measurements with the same accuracy as classic microthermometry . Diez‐y‐Riega et al .…”

“…They find that a good knowledge of the polarization properties of the optical devices of the Raman spectrometer and a correct positioning of the sample thus result in salinity (chloride concentration) measurements with the same accuracy as classic microthermometry. [140] Diez-y-Riega et al reported thermal lens detection of one and two-color laser excitation of benzene in cryogenic liquid solutions. They used a three-level model to explain signal enhancement with respect to one-color laser excitation under the same experimental conditions.…”