Raman calibration of sulfate-bearing polymineralic mixtures: a S quantification in sedimentary rocks on Mars

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Marco E. Ciriotti
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Iscritto il: ven 25 giu, 2004 11:31
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Raman calibration of sulfate-bearing polymineralic mixtures: a S quantification in sedimentary rocks on Mars

Messaggio da Marco E. Ciriotti » sab 15 set, 2018 12:04

Prossima pubblicazione.

Referenza:
▪ Larre, C., Morizet, Y., Guillot-Deudon, C., Baron, F., Mangold, N. (2018): Quantitative Raman calibration of sulfate-bearing polymineralic mixtures: a S quantification in sedimentary rocks on Mars. Mineralogical Magazine, 82, (in press).

Abstract:
The NASA 2020 Mars mission is a Curiosity-type rover aiming to improve the knowledge of the geologic and climatic evolution of Mars and collect rock samples for future return to Earth. The new rover presents a payload of seven instruments including the SuperCam instrument which is constituted of four tools including a Raman spectrometer. This Raman device will be non-destructive and will analyze the surface remotely in order to determine the mineralogy of rocks and, by extent, to detect and quantify major elements such as sulfur. Sulfur has been detected under sulfate forms (Ca,Mg,Fe-sulfates) in sedimentary rocks. This element is difficult to quantify using the laser ablation tool of the ChemCam instrument onboard the Curiosity rover. We propose a Raman calibration to constrain the sulfur abundance in multi-minerallic mixtures.. We acquired Raman signatures on binary and ternary mechanical mixtures containing Ca and Mg sulfates, mixed with natural silicate minerals: olivine, clinopyroxene, orthopyroxene and plagioclase; and supposed to be relevant of basaltic-sedimentary rocks at the surface of Mars. Specific processing of Raman spectra extracted from our mixtures using Voigt function allows us to recover the initial proportions of our preparations on Ca and Mg sulfates. From these simulations, calibration equations have been provided allowing us to determine sulfate proportions (CaSO4 and MgSO4) in a mixture with basaltic minerals. With the presented calibration, S can be quantified at a lower limit of 0.7 wt % in martian soil.
Marco E. Ciriotti

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