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Beckettite, Ca₂V₆Al₆O₂₀, a new mineral in a Type A refractory inclusion from Allende and clues to processes in the early solar system

Ma, Chi and Krot, Alexander N. and Paque, Julie and Tschauner, Oliver and Nagashima, Kazuhide (2021) Beckettite, Ca₂V₆Al₆O₂₀, a new mineral in a Type A refractory inclusion from Allende and clues to processes in the early solar system. Meteoritics and Planetary Science, 56 (12). pp. 2265-2272. ISSN 1086-9379. doi:10.1111/maps.13771. https://resolver.caltech.edu/CaltechAUTHORS:20211208-560283000

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Abstract

Beckettite (Ca₂V₆Al₆O₂₀; IMA 2015-001) is a newly discovered refractory mineral, occurring as micrometer-sized grains intergrown with hibonite and perovskite, and surrounded by secondary grossular, anorthite, coulsonite, hercynite, and corundum. It occurs within highly altered areas in a V-rich, Type A Ca-Al-rich inclusion (CAI), A-WP1, from the Allende CV3 carbonaceous chondrite. The type beckettite has an empirical formula of (Ca_(1.99)Na_(0.01))(V³⁺_(3.47)Al_(1.40)Ti⁴⁺_(0.57)Mg_(0.25)Sc_(0.08)Fe²⁺_(0.04))(Al_(5.72)Si_(0.28))O₂₀, with a triclinic structure in space group P1 and cell parameters a = 10.367 Å, b = 10.756 Å, c = 8.895 Å, α = 106.0°, β = 96.0°, γ = 124.7°, V = 739.7 Å3, and Z = 2, which leads to a calculated density of 3.67 g cm⁻³. Beckettite’s general formula is Ca₂(V,Al,Ti,Mg)₆Al₆O₂₀ and the endmember formula is Ca2V6Al6O20. Beckettite is slightly ¹⁶O-depleted (Δ¹⁷O = −16 ± 2‰) compared to the coexisting hibonite and spinel −24 ± 2‰. Beckettite is a primary high-temperature mineral resulting from igneous crystallization of an ¹⁶O-rich V-rich CAI melt together with V-bearing hibonite, perovskite, burnettite, spinel, and paqueite. Subsequently, beckettite experienced an incomplete isotope exchange with an ¹⁶O-poor aqueous fluid (Δ¹⁷O = −3 ± 2‰) on the Allende parent asteroid.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1111/maps.13771DOIArticle
ORCID:
AuthorORCID
Ma, Chi0000-0002-1828-7033
Krot, Alexander N.0000-0002-2278-8519
Paque, Julie0000-0003-0554-7876
Tschauner, Oliver0000-0003-3364-8906
Nagashima, Kazuhide0000-0002-9322-3187
Alternate Title:Beckettite, Ca2V6Al6O20, a new mineral in a Type A refractory inclusion from Allende and clues to processes in the early solar system
Additional Information:© 2021 The Meteoritical Society (MET). Issue Online: 28 December 2021; Version of Record online: 07 December 2021; Manuscript accepted: 12 November 2021; Manuscript received: 30 September 2021. SEM, EBSD, and EPMA analyses were carried out at the Caltech GPS Division Analytical Facility, which is supported, in part, by NSF Grants EAR-0318518 and DMR-0080065. We thank Samuel Ebert and associate editor Yves Marrocchi for their constructive reviews. Data Availability Statement. Data available on request from the authors.
Funders:
Funding AgencyGrant Number
NSFEAR-0318518
NSFDMR-0080065
Issue or Number:12
DOI:10.1111/maps.13771
Record Number:CaltechAUTHORS:20211208-560283000
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20211208-560283000
Official Citation:Ma, C., Krot, A.N., Paque, J., Tschauner, O. and Nagashima, K. (2021), Beckettite, Ca2V6Al6O20, a new mineral in a Type A refractory inclusion from Allende and clues to processes in the early solar system. Meteorit Planet Sci, 56: 2265-2272. https://doi.org/10.1111/maps.13771
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:112282
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:09 Dec 2021 17:47
Last Modified:03 Jan 2022 22:19

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