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A unifying model for the accretion of chondrules and matrix
- Source :
- Proceedings of the National Academy of Sciences of the United States of America, Proceedings of the National Academy of Sciences of the United States of America, National Academy of Sciences, 2019, ⟨10.1073/pnas.1907592116⟩, Proceedings Of The National Academy Of Sciences Of The United States Of America (0027-8424) (Natl Acad Sciences), 2019-09, Vol. 116, N. 38, P. 18860-18866, Proceedings of the National Academy of Sciences
- Publication Year :
- 2019
- Publisher :
- HAL CCSD, 2019.
-
Abstract
- Significance An impasse exists between chemical and astrophysical models that explore the accretion of the Solar System’s building blocks, the chondrites. To resolve this issue means to gain an understanding of the dimensions of mass transport in the early Solar System and, hence, a crucial insight into the volatile inventory of the terrestrial planets. Here, we use element volatility patterns of chondrules and their dust rims to show that these main constituents of chondrites are not complementary to each other and did not form in the same chemical reservoirs. We propose a unifying chondrule and matrix accretion model that necessitates significant mass transport in the protoplanetary disk and an inward flux of volatile-rich CI-like (Ivuna-type carbonaceous chondrite) dust.<br />The so far unique role of our Solar System in the universe regarding its capacity for life raises fundamental questions about its formation history relative to exoplanetary systems. Central in this research is the accretion of asteroids and planets from a gas-rich circumstellar disk and the final distribution of their mass around the Sun. The key building blocks of the planets may be represented by chondrules, the main constituents of chondritic meteorites, which in turn are primitive fragments of planetary bodies. Chondrule formation mechanisms, as well as their subsequent storage and transport in the disk, are still poorly understood, and their origin and evolution can be probed through their link (i.e., complementary or noncomplementary) to fine-grained dust (matrix) that accreted together with chondrules. Here, we investigate the apparent chondrule–matrix complementarity by analyzing major, minor, and trace element compositions of chondrules and matrix in altered and relatively unaltered CV, CM, and CR (Vigarano-type, Mighei-type, and Renazzo-type) chondrites. We show that matrices of the most unaltered CM and CV chondrites are overall CI-like (Ivuna-type) (similar to solar composition) and do not reflect any volatile enrichment or elemental patterns complementary to chondrules, the exception being their Fe/Mg ratios. We propose to unify these contradictory data by invoking a chondrule formation model in which CI-like dust accreted to so-called armored chondrules, which are ubiquitous in many chondrites. Metal rims expelled during chondrule formation, but still attached to their host chondrule, interacted with the accreted matrix, thereby enriching the matrix in siderophile elements and generating an apparent complementarity.
- Subjects :
- Solar System
chondrules
secondary alteration
010502 geochemistry & geophysics
01 natural sciences
Astrobiology
Physics::Geophysics
Matrix (mathematics)
Earth, Atmospheric, and Planetary Sciences
Planet
Chondrite
0103 physical sciences
Astrophysics::Solar and Stellar Astrophysics
010303 astronomy & astrophysics
Astrophysics::Galaxy Astrophysics
0105 earth and related environmental sciences
complementarity
Physics
LA-ICPMS
Multidisciplinary
Trace element
Chondrule
Accretion (astrophysics)
13. Climate action
Asteroid
[SDU]Sciences of the Universe [physics]
Physics::Space Physics
Physical Sciences
Astrophysics::Earth and Planetary Astrophysics
Subjects
Details
- Language :
- English
- ISSN :
- 00278424 and 10916490
- Database :
- OpenAIRE
- Journal :
- Proceedings of the National Academy of Sciences of the United States of America, Proceedings of the National Academy of Sciences of the United States of America, National Academy of Sciences, 2019, ⟨10.1073/pnas.1907592116⟩, Proceedings Of The National Academy Of Sciences Of The United States Of America (0027-8424) (Natl Acad Sciences), 2019-09, Vol. 116, N. 38, P. 18860-18866, Proceedings of the National Academy of Sciences
- Accession number :
- edsair.doi.dedup.....7aa56f7243809e6024cae286dec32bae