Raman spectra and X-ray diffraction of merrillite at various temperatures

The Mars Sample Return (MSR) is a near future mission to return samples from the surface of Mars to the Earth. The field operations to carry out data collection, selection of the samples, and sampling procedure, mainly related to the CanMars MSR analog mission, are well‐studied and published. In contrast, studies related to the methodology implemented to characterize the mineralogy of the returned samples are scarcer and focused on biosignature detection. This work presents a non‐destructive analytical methodology based on Raman microscopy (single point and imaging), micro‐energy dispersive X‐ray fluorescence imaging analysis, and scanning electron microscopy coupled to energy dispersive spectroscopy that could be used as a first analytical characterization for the Martian samples that will be returned to the Earth in the upcoming MSR mission, before any destructive analysis. The analytical methodology has been tested on a fragment of the Northwest Africa 1950 Martian meteorite, which gives us a mineralogical characterization of the meteorite. This methodology also allowed to define several chemical reactions taking place in some of the mineral phases (olivines and ilmenite) of the meteorite. In addition to the geochemical characterization of the samples, the fact that this methodology allows to assess the chemical transformations in several minerals gives important clues for describing mineral processes and geological evolution that took place on Mars. This work also shows the advantages and disadvantages that each of the techniques employed has when performing a mineralogical characterization, the information that each one can provide and the importance of combining them.

Section: Results and Discusionmentioning

confidence: 96%

Development of non‐destructive analytical strategies based on Raman spectroscopy and complementary techniques for Mars Sample Return tested on Northwest Africa 1950 Martian meteorite

Coloma

García‐Florentino

Huidobro

et al. 2022

“…Phosphates such as apatite and merrillite have characteristic yet distinct Raman spectra. Their Raman spectra have been described in terrestrial and extraterrestrial samples 27,61–64 . The symmetric stretching vibration mode of PO 4 3− provides the most intense Raman peak between 950 and 990 cm −1 , labeled as ν 1 .…”

Section: Resultsmentioning

confidence: 99%

“…Their Raman spectra have been described in terrestrial and extraterrestrial samples. 27,[61][62][63][64] The symmetric stretching vibration mode of PO 4 3À provides the most intense Raman peak between 950 and 990 cm À1 , labeled as ν 1 . Apatite has a single ν 1 band at 964 cm À1 , and merrillite has a doublet of peaks around 955 and 975 cm À1 .…”

Section: Phosphates: Apatite and Merrillitementioning

confidence: 99%

Raman spectroscopy investigations of the Martian regolith breccia Northwest Africa 7533: A support to in situ Raman spectroscopy on Mars

Malarewicz

Beyssac

Zanda

et al. 2023

Using continuous-wave and time-resolved Raman spectroscopy, we investigate and characterize the mineralogy of the NWA 7533 meteorite, a unique Martian regolith breccia. This meteorite is a crucial sample, giving a rare access to the formation and evolution of the primitive Martian crust, with crystallization processes beginning up to $4.4 Ga years ago. We provide an overview of Raman spectra for feldspar, plagioclase, pyroxene, olivine, apatite, merrillite, zircon, pyrite, and various Fe-Cr-Ti oxides like magnetite, hematite, ilmenite, and rutile. Most analytical points are paired with previous electron microprobe

“…They were detected by single Raman point mode on small crystals of the meteorite. Figure 6a shows the detected merrillite [Ca 9 NaMg(PO 4 ) 7 ] [ 49 ] through its main Raman bands at 356 (w), 410 (m), 448 (vw), 547 (vw), 595 (vw), 622 (w), 958 (vs), 974 (vs), 1046 (w), and 1082 (w) cm −1 . [ 49 ] Merrillite does not occur on Earth as a discrete mineral phase, and there is not any report about the presence of this phosphate on Mars.…”

Section: Resultsmentioning

confidence: 99%

“…Figure 6a shows the detected merrillite [Ca 9 NaMg(PO 4 ) 7 ] [ 49 ] through its main Raman bands at 356 (w), 410 (m), 448 (vw), 547 (vw), 595 (vw), 622 (w), 958 (vs), 974 (vs), 1046 (w), and 1082 (w) cm −1 . [ 49 ] Merrillite does not occur on Earth as a discrete mineral phase, and there is not any report about the presence of this phosphate on Mars. However, merrillite is a dominant primary Ca‐phosphate mineral in Martian meteorites, which raises the question of their presence in such samples.…”

Section: Resultsmentioning

confidence: 99%

Mineralogy of the RBT 04262 Martian meteorite as determined by micro‐Raman and micro‐X‐ray fluorescence spectroscopies

Huidobro

Aramendia

García‐Florentino

et al. 2021

Martian meteorites and terrestrial analogs represent the only samples available on Earth for studying mineralogy features of our neighbor planet Mars. This work characterizes the Roberts Massif (RBT) 04262 Martian meteorite by using mainly Raman spectroscopy. By means of this technique, it was confirmed that the meteorite matrix is composed by pyroxene and plagioclase (converted to maskelynite due to the shock pressure). Olivine-coarse grains embedded in the matrix were also observed. These grains were coated by hydrated magnesium and calcium sulfates, which would belong to the Mars sulfate deposits or to the terrestrial weathering. Although the sulfates could be formed on Mars due to the oxidation of sulfides or elemental sulfur along the sulfur Mars cycle, their distribution along cracks and fractures confirm that are weathering products. However, other S-bearing compounds that belong to Mars were found, such as elemental sulfur and a thermally transformed iron sulfide.Finally, the calcium phosphate merrillite and titanomagnetite were also detected. Taking this into account, the minerals found were classified into primary minerals that belong to Mars (pyroxene, olivine, elemental sulfur, and titanomagnetite), secondary ones that are alteration products of the primary minerals (maskelynite, iron sulfide, and merrillite), and terrestrial weathering products (sulfates gypsum and epsomite).