Micro‐Raman study of cesanite (Ca₂Na₃ (OH)(SO₄)₃) in chloride segregations from Udachnaya‐East kimberlites

Abstract

Cesanite (Ca2Na3(OH)(SO4)3), a rare mineral, has been found in a few places restricted to a geothermal field and caves. We report the new occurrence of cesanite in quite different geological site—within sulfate‐rich melt inclusions in chloride segregations from kimberlites of Udachnaya‐East pipe (Siberia). Two halite generations: сesanite free and сesanite‐bearing, were distinguished in concentrically zonal segregations according to the results of the mineral and sulfate melt inclusion study by micro‐Raman spectroscopy and SEM‐EDS. We have applied the Raman spectroscopy and first principles calculations to understand structural and vibrational properties of cesanite daughter mineral in polyphase sulfate inclusions. Polarized spectra provided additional information on the overlapped components of the spectral profile. The Raman spectra of cesanite in the range of OH stretching vibrations are reported for the first time. The study aims to clarify the source of the NaSCl‐enrichment in the Udachnaya‐East pipe, which is highly discussed.

Europium (II) Sulfate EuSO4: Synthesis Methods, Crystal and Electronic Structure, Luminescence Properties

“…[51] The sharp band at 990 cm À 1 in the infrared spectrum and very strong band in the Raman spectrum at 994 cm À 1 are representing symmetric stretching modes of the SO 4 tetrahedra. [52] Bands related to asymmetric bending modes observed in the region of 550-680 cm À 1 in the infrared spectrum are in the range of 590-660 cm À 1 in the Raman spectrum. Raman bands between 420 and 480 cm À 1 are symmetric bending vibrations of sulfate ions.…”

“…Broad bands related to asymmetric stretching vibrations of [SO 4 ] 2− ions observed in the regions of 1025–1250 cm −1 [51] . The sharp band at 990 cm −1 in the infrared spectrum and very strong band in the Raman spectrum at 994 cm −1 are representing symmetric stretching modes of the SO 4 tetrahedra [52] . Bands related to asymmetric bending modes observed in the region of 550–680 cm −1 in the infrared spectrum are in the range of 590–660 cm −1 in the Raman spectrum.…”

The Oxygen Isotopic Composition of Samples Returned from Asteroid Ryugu with Implications for the Nature of the Parent Planetesimal

“…The spectra shown in Figure 2 are the average of between 9 and 13 individual spectra for each sample. The region of the Raman spectra exhibiting stretching modes of water from 3000 to 3800 cm −1 (e.g., Shahar & Bassett 2005;Kolesov 2006;de Ligny et al 2013;Grishina et al 2021) displays a complex profile of overlapping bands in all three samples. The five bands at 3066, 3194, 3306, 3400, and 3510 cm −1 used to fit the spectra are consistent with analogous molecular water features observed in other water-bearing minerals, like those in kimberlite inclusions (e.g., Grishina et al 2021).…”

“…The local baselines were fit with linear functions. The region of Raman spectra corresponding to water stretching modes, from 3000 to 3800 cm −1 (e.g., Shahar & Bassett 2005;Kolesov 2006;de Ligny et al 2013;Grishina et al 2021), was fit using Lorentzian line shapes (Bancroft et al 2018). Five bands of molecular water at 3066, 3194, 3306, 3400, and 3510 cm −1 were used to fit the spectra.…”

GeoRaman

“…Grishina et al [ 13 ] reported the new occurrence of cesanite in quite different geological site within sulfate‐rich melt inclusions in chloride segregations from kimberlites of Udachnaya‐East pipe (Siberia). Cesanite (Ca 2 Na 3 (OH)(SO 4 ) 3 ) is a rare mineral found in a few places restricted to a geothermal field and caves.…”