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Metamorphosed calcium-aluminum-rich inclusions in CK carbonaceous chondrites
- Source :
- Meteoritics and Planetary Science, Meteoritics and Planetary Science, 2014, 49 (3), pp.419-452. ⟨10.1111/maps.12260⟩, Meteoritics and Planetary Science, Wiley, 2014, 49 (3), pp.419-452. ⟨10.1111/maps.12260⟩
- Publication Year :
- 2014
- Publisher :
- HAL CCSD, 2014.
-
Abstract
- CK chondrites are the only group of carbonaceous chondrites with petrologic types ranging from 3 to 6. Although CKs are described as calcium-aluminum-rich inclusion (CAI)-poor objects, the abundance of CAIs in the 18 CK3–6 we analyzed ranges from zero to approximately 16.4%. During thermal metamorphism, some of the fine-grained CAIs recrystallized as irregular assemblages of plagioclase + Ca-rich pyroxene ! olivine ! Ca-poor pyroxene ! magnetite. Coarse-grained CAIs display zoned spinel, fassaite destabilization, and secondary grossular and spinel. Secondary anorthite, grossular, Ca-rich pyroxene, and spinel derive from the destabilization of melilite, which is lacking in all CAIs investigated. The Al-Mg isotopic systematics measured in fine- and coarsegrained CAIs from Tanezrouft (Tnz) 057 was affected by Mg redistribution. The partial equilibration of Al-Mg isotopic signatures obtained in the core of a coarse-grained CAI (CG1-CAI) in Tnz 057 may indicate a lower peak temperature for Mg diffusion of approximately 540–580 °C, while grossular present in the core of this CAI indicates a higher temperature of around 800 °C for the metamorphic event on the parent body of Tnz 057. Excluding metamorphic features, the similarity in nature and abundance of CAIs in CK and CV chondrites confirms that CVs and CKs form a continuous metamorphic series from type 3 to 6.
- Subjects :
- Olivine
Grossular
Spinel
Geochemistry
Melilite
Pyroxene
engineering.material
Anorthite
[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]
Geophysics
Space and Planetary Science
Chondrite
visual_art
engineering
visual_art.visual_art_medium
Plagioclase
Geology
Subjects
Details
- Language :
- English
- ISSN :
- 10869379 and 19455100
- Database :
- OpenAIRE
- Journal :
- Meteoritics and Planetary Science, Meteoritics and Planetary Science, 2014, 49 (3), pp.419-452. ⟨10.1111/maps.12260⟩, Meteoritics and Planetary Science, Wiley, 2014, 49 (3), pp.419-452. ⟨10.1111/maps.12260⟩
- Accession number :
- edsair.doi.dedup.....ec06950a83c281688315db634e01ec47