title: Approximate chemical analysis of volcanic glasses using Raman spectroscopy.
abstract: The effect of chemical composition on the Raman spectra of a series of natural calcalkaline silicate glasses has been quantified by performing electron microprobe analyses and obtaining Raman spectra on glassy filaments (~450 µm) derived from a magma mingling experiment. The results provide a robust compositionally-dependent database for the Raman spectra of natural silicate glasses along the calcalkaline series. An empirical model based on both the acquired Raman spectra and an ideal mixing equation between calcalkaline basaltic and rhyolitic end-members is constructed enabling the estimation of the chemical composition and degree of polymerization of silicate glasses using Raman spectra. The model is relatively insensitive to acquisition conditions and has been validated using the MPI-DING geochemical standard glasses1 as well as further samples. The methods and model developed here offer several advantages compared with other analytical and spectroscopic methods such as infrared spectroscopy, X-ray fluorescence spectroscopy, electron and ion microprobe analyses, inasmuch as Raman spectroscopy can be performed with a high spatial resolution (1 µm2) without the need for any sample preparation as a nondestructive technique. This study represents an advance in efforts to provide the first database of Raman spectra for natural silicate glasses and yields a new approach for the treatment of Raman spectra, which allows us to extract approximate information about the chemical composition of natural silicate glasses using Raman spectroscopy. We anticipate its application in handheldin situterrestrial field studies of silicate glasses under extreme conditions (e.g. extraterrestrial and submarine environments).
authors.affiliation: Department of Earth and Environmental Sciences Ludwig-Maximilians-Universität (LMU) Theresienstrasse 41/III 80333 München Germany.
authors.forename: Danilo
authors.initials: D
authors.lastname: Di Genova
authors.affiliation: Department of Earth and Environmental Sciences Ludwig-Maximilians-Universität (LMU) Theresienstrasse 41/III80333 München Germany; Department of Earth Sciences University of Perugia Piazza Università 06100 Perugia Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Morgavi
authors.affiliation: Department of Earth and Environmental Sciences Ludwig-Maximilians-Universität (LMU) Theresienstrasse 41/III 80333 München Germany.
authors.forename: Kai-Uwe
authors.initials: KU
authors.lastname: Hess
authors.affiliation: Géomatériaux CNRS-IPGP UMR 7154 Paris Sorbonne Cité, 1 rue Jussieu 75005 Paris France.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Neuville
authors.affiliation: Department of Earth and Environmental Sciences Ludwig-Maximilians-Universität (LMU) Theresienstrasse 41/III 80333 München Germany.
authors.forename: Nikita
authors.initials: N
authors.lastname: Borovkov
authors.affiliation: Department of Earth Sciences University of Perugia Piazza Università 06100 Perugia Italy.
authors.forename: Diego
authors.initials: D
authors.lastname: Perugini
authors.affiliation: Department of Earth and Environmental Sciences Ludwig-Maximilians-Universität (LMU) Theresienstrasse 41/III 80333 München Germany.
authors.forename: Donald B
authors.initials: DB
authors.lastname: Dingwell
keywords: chemical analysis; identification; natural silicate glasses; planetary science; volcanology