Premium
The role of Bells in the continuous accretion between the CM and CR chondrite reservoirs
Author(s) -
Kooten Elishevah,
Cavalcante Larissa,
Wielandt Daniel,
Bizzarro Martin
Publication year - 2020
Publication title -
meteoritics and planetary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 100
eISSN - 1945-5100
pISSN - 1086-9379
DOI - 10.1111/maps.13459
Subject(s) - chondrite , chondrule , carbonaceous chondrite , accretion (finance) , meteorite , astrobiology , geology , parent body , formation and evolution of the solar system , geochemistry , astrophysics , physics
CM meteorites are dominant members of carbonaceous chondrites ( CC s), which evidently accreted in a region separated from the terrestrial planets. These chondrites are key in determining the accretion regions of solar system materials, since in Mg and Cr isotope space, they intersect between what are identified as inner and outer solar system reservoirs. In this model, the outer reservoir is represented by metal‐rich carbonaceous chondrites ( MRCC s), including CR chondrites. An important question remains whether the barrier between MRCC s and CC s was a temporal or spatial one. CM chondrites and chondrules are used here to identify the nature of the barrier as well as the timescale of chondrite parent body accretion. We find based on high precision Mg and Cr isotope data of seven CM chondrites and 12 chondrules, that accretion in the CM chondrite reservoir was continuous lasting < 3 Myr and showing late accretion of MRCC ‐like material reflected by the anomalous CM chondrite Bells. We further argue that although MRCC s likely accreted later than CM chondrites, CR chondrules must have initially formed from a reservoir spatially separated from CM chondrules. Finally, we hypothesize on the nature of the spatial barrier separating these reservoirs.