Remote Geochemical and Mineralogical Analyses under Venus Atmospheric Conditions by Raman - Laser Induced Breakdown Spectroscopy (LIBS)
Abstract
The extreme Venus surface temperature ( 740 K) and atmospheric pressure ( 93 atm) create a challenging environment for surface geochemical and mineralogical investigations. Such investigations must be completed within hours of landing before the lander will be overcome by the harsh atmosphere. A combined remote Raman - LIBS spectrometer (RLS) is capable of accomplishing the geochemical science goals without the risks associated with collecting samples and bringing them into the lander. Wiens et al. [1], Sharma et al. [2] and Clegg et al. [3] demonstrated that both analytical techniques can be integrated into a single instrument similar to the SuperCam instrument selected for the Mars 2020 rover. The focus of this paper is to explore the capability to probe geologic samples by Raman and LIBS and demonstrate quantitative analysis under Venus surface conditions. Raman and LIBS are highly complementary analytical techniques capable of determining both the mineralogical and geochemical composition of Venus surface samples. These techniques have the potential to profoundly increase our knowledge of the Venus surface composition, which is currently limited to geochemical data from the Venera and VEGA landers [4]. Based on the observed compositional differences and recognizing the imprecise nature of the existing data, samples were chosen to constitute a Venus-analog suite for this study. LIBS data reduction involved generating a partial least squares (PLS) model with a subset of the rock powder standards to quantitatively determine the major elemental abundance of the remaining samples. The Raman experiments have been conducted under supercritical CO2 involving single-mineral and mixed-mineral samples containing talc, olivine, pyroxenes, feldspars, anhydrite, barite, and siderite. These experiments involve a new RLS prototype similar to the SuperCam instrument as well a new 2 m long pressure chamber capable of simulating the Venus surface temperature and pressure. Results of these combined Raman-LIBS investigations will be presented and discussed. [1] Wiens R.C., et al. (2005) Spect. Acta A 61, 2324; [2] Sharma, S. K. et al. (2007) Spect. Acta A, 68 , 1036 (2007); [3] Clegg, S.M. et al. (2014) Appl. Spec. 68, 925; [4] Barsukov VL (1992) In Venus Geology, Geochemistry, and Geophysics, Univ. Arizona Press, pp. 165.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.P41B2068C
- Keywords:
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- 6207 Comparative planetology;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTSDE: 5415 Erosion and weathering;
- PLANETARY SCIENCES: SOLID SURFACE PLANETSDE: 5455 Origin and evolution;
- PLANETARY SCIENCES: SOLID SURFACE PLANETSDE: 8147 Planetary interiors;
- TECTONOPHYSICS