Mineralogy of the LAR 12095 Martian shergottite as determined by micro‐Raman and micro‐X‐ray fluorescence spectroscopies

Abstract

In this work, the geochemical characterization of the olivine‐phyric Martian shergottite LAR 12095 was performed by using two complementary analytical techniques: micro‐Raman and micro‐energy dispersive X‐ray fluorescence spectroscopies. Thanks to this methodology, olivine, pyroxene, and ilmenite were detected as primary minerals from Mars. Maskelynite, hematite, anatase, chromite, merrillite, oxidized mackinawite, pyrrhotite, elemental sulfur, marcasite, jarosite, epsomite, and gypsum were classified as secondary minerals. The major novelty of this work is that alterations under anaerobic and aerobic conditions of S‐bearing minerals can be appreciated. In this sense, primary sulfides were altered to secondary sulfides, elemental sulfur and sulfates under the oxygen‐free Martian atmosphere. However, in the Earth's oxidizing atmosphere, primary sulfides are weathered to iron oxides, such as hematite. In addition, it should be highlighted that the presence of ilmenite, mackinawite, elemental sulfur, and jarosite has been reported for the first time in this meteorite.

GeoRaman 2022

“…A sample of another Martian shergottite meteorite (LAR 12095) was studied by Huidobro et al 8 using micro-Raman and micro-X-ray fluorescence spectroscopies. They identified olivine, pyroxene and ilmenite as primary minerals phases, while the additionally detected minerals such as maskelynite, hematite, anatase, chromite, merrillite, oxidized mackinawite, pyrrhotite, elemental sulfur, marcasite, jarosite, epsomite and gypsum were interpreted as secondary minerals, which are the products of alteration under mostly anoxic atmosphere of Mars.…”

Characterization of primary silicate minerals in Earth‐like bodies via Raman spectroscopy

“…Among the notable studies in this area is the analysis of the Martian meteorite Northwest Africa (NWA) 2975 through Raman spectroscopy, which identified its major minerals as pyroxenes (primarily augite, pigeonite, and enstatite) and plagioclases (mainly shocked maskelynite). 1 Another significant contribution comes from Huidobro et al, 2 who utilized two complementary analytical techniques, micro-Raman and micro-energy-dispersive X-ray fluorescence spectroscopies, for the geochemical characterization of the Martian shergottite LAR 12095. This study revealed that olivine, pyroxene, and ilmenite were the primary minerals present in this Martian meteorite.…”