Rai, A.K.; Pati, J.K.; Parigger, C.G.; Rai, A.K. Plasma Spectroscopy of Various Types of Gypsum: An Ideal Terrestrial Analogue. Atoms2019, 7, 72.
Rai, A.K.; Pati, J.K.; Parigger, C.G.; Rai, A.K. Plasma Spectroscopy of Various Types of Gypsum: An Ideal Terrestrial Analogue. Atoms 2019, 7, 72.
Rai, A.K.; Pati, J.K.; Parigger, C.G.; Rai, A.K. Plasma Spectroscopy of Various Types of Gypsum: An Ideal Terrestrial Analogue. Atoms2019, 7, 72.
Rai, A.K.; Pati, J.K.; Parigger, C.G.; Rai, A.K. Plasma Spectroscopy of Various Types of Gypsum: An Ideal Terrestrial Analogue. Atoms 2019, 7, 72.
Abstract
The first detection of gypsum (CaSO4.2H2O) by the Mars Science Laboratory (MSL) rover Curiosity in the Gale Crater, Mars created a profound impact on planetary science and exploration. The unique capability of plasma spectroscopy involving in situ elemental analysis in extraterrestrial environments, suggesting the presence of water in the red planet based on phase characterization and providing a clue to Martian paleoclimate. The key to gypsum as an ideal paleoclimate proxy lies in its textural variants, and in this study terrestrial gypsum samples from varied locations and textural types have been analyzed by Laser Induced Breakdown Spectroscopy (LIBS) technique. Petrographic, sub-microscopic and powder X-ray diffraction characterizations confirm the presence of gypsum (hydrated calcium sulphate; CaSO4.2H2O), bassanite (semi-hydrated calcium sulphate; CaSO4.1/2H2O) and anhydrite (anhydrous calcium sulphate; CaSO4) along with accessory phases (quartz and jarosite). The principal component analysis of LIBS spectra from texturally varied gypsums can be differentiated from one another because of the chemical variability in their elemental concentrations. The concentration of gypsum is determined from the partial least-square regressions model. Rapid characterization of gypsum samples with LIBS is expected to work well in extraterrestrial environments.
Keywords
laser-induced plasma; atomic spectroscopy; laser-induced breakdown spectroscopy; 29 atomic spectroscopy; principal component analysis; partial least-square regression; gypsum; Mars
Subject
Physical Sciences, Atomic and Molecular Physics
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
