THE CHROMIUM ISOTOPIC COMPOSITION OF THE UNGROUPED CARBONACEOUS CHONDRITE TAGISH LAKE

Early solar materials bear a variety of isotopic anomalies that reflect compositional differences deriving from distinct stellar nucleosynthetic processes. As shown in previous studies, the stepwise dissolution with increasing acid strengths of bulk rock carbonaceous chondrites liberates Cr with bot...

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Bibliographic Details
Published in:The Astrophysical Journal
Main Authors: Petitat, M., Birck, J. -L., Luu, T. H., Gounelle, M.
Format: Article in Journal/Newspaper
Language:English
Published: 2011
Subjects:
meteorites
meteors
meteoroids
nuclear reactions
nucleosynthesis
abundances
supernovae: general
EARLY SOLAR-SYSTEM
PARENT BODY
CI CHONDRITES
CARBONATES
ANOMALIES
ORGUEIL
CLUES
GEOCHEMISTRY
CHRONOLOGY
Tagish
Tagish Lake
Murchison
Online Access:https://hdl.handle.net/1983/0c9b0c04-de50-41b7-bdbd-33438fb7e5bc
https://research-information.bris.ac.uk/en/publications/0c9b0c04-de50-41b7-bdbd-33438fb7e5bc
https://doi.org/10.1088/0004-637X/736/1/23
Description
Summary:Early solar materials bear a variety of isotopic anomalies that reflect compositional differences deriving from distinct stellar nucleosynthetic processes. As shown in previous studies, the stepwise dissolution with increasing acid strengths of bulk rock carbonaceous chondrites liberates Cr with both excesses and deficits in Cr-53 and Cr-54 relative to the terrestrial standard. The magnitude of the Cr-54 variations within a meteorite decreases in the sequence CI1 > CR2 > CM2 > CV3 > CO3 > CK4 and correlates with the degree of metamorphism of each carbonaceous chondrite class. This study shows that the Tagish Lake meteorite presents the highest excesses in Cr-54 ever measured in a bulk silicate phase. According to this study, the Tagish Lake meteorite is composed of the least re-equilibrated material known at this time. The magnitude of Cr-54 variation decreases now in the following sequence: Tagish Lake (ungrouped CI2) > Orgueil (CI1) > Murchison (CM2) > Allende (CV2). Moreover, this study shows that excesses in Cr-53 relative to Earth can be interpreted as representing the extent of aqueous alteration on meteorite parent bodies. Finally, the high Cr-54 anomalies measured in this meteorite make Tagish Lake one of the major targets to decipher the host of these anomalies.

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