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Development of a new laboratory technique for high‐temperature thermal emission spectroscopy of silicate melts
Author(s) -
Lee Rachel J.,
Ramsey Michael S.,
King Penelope L.
Publication year - 2013
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1002/jgrb.50197
Subject(s) - emissivity , silicate , materials science , spectrometer , fourier transform infrared spectroscopy , emission spectrum , spectroscopy , mineralogy , infrared , spectral line , infrared spectroscopy , analytical chemistry (journal) , optics , chemistry , physics , astronomy , organic chemistry , chromatography
With the prevalence of glass and molten silicates in volcanic environments, and the important role of surface emissivity in thermal infrared (TIR) measurements, it is imperative to characterize accurately the spectral features associated with silicate glasses and melts. A microfurnace has been developed specifically for use with a laboratory Fourier transform infrared (FTIR) spectrometer to collect the first in situ TIR emission spectra of actively melting and cooling silicate glasses. The construction, implementation, and calibration of the microfurnace spectrometer system are presented here. Initial testing of the microfurnace is also discussed, which includes acquisition of thermal emission spectra of a quartz powder (unmelted), a melted and cooled oligoclase feldspar, and glassy melt of rhyolitic composition. Unlike a solid material, which may only have bending and stretching vibrations within its molecular structure, a fully molten material will exhibit several more degrees of freedom in structural movement, thus changing its spectral character. Differences in spectral behavior and morphology are observed between a glass in a solid state and its molten counterpart, confirming previous field measurements of lower emissivity upon melting. This laboratory microfurnace system has been designed to quantify the TIR emission spectral behavior of glassy materials in various physical states. Ultimately, it is hoped that the microfurnace data will help improve the ability of field‐based, airborne, and spaceborne TIR data to characterize glassy volcanic terranes.