Publication Date:
2022-05-25
Description:
Author Posting. © The Author(s), 2018. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Earth and Planetary Science Letters 505 (2019): 131-140, doi:10.1016/j.epsl.2018.10.029.
Description:
Vanadium (V) isotopes have been hypothesized to record irradiation processes in the
early solar system through production of the minor 50V isotope. However, because V only
possesses two stable isotopes it is difficult to distinguish irradiation from other processes such as
stable isotope fractionation and nucleosynthetic heterogeneity that could also cause V isotope
variation. Here we perform the first detailed investigation of V isotopes in ordinary and
carbonaceous chondrites to investigate the origin of any variation. We also perform a three-laboratory inter-calibration for chondrites, which confirms that the different chemical separation
protocols do not induce V isotope analytical artifacts as long as samples are measured using
medium resolution multiple collector inductively coupled plasma mass spectrometry (MCICPMS).
Vanadium isotope compositions (51V/50V) of carbonaceous chondrites correlate with
previously reported nucleosynthetically derived excesses in 54Cr. Both 51V and 54Cr are the most
neutron-rich of their respective elements, which may suggest that pre-solar grains rich in r-process isotopes is the primary cause of the V-Cr isotope correlation. Vanadium isotope ratios of
ordinary chondrite groups and Earth form a weaker correlation with 54Cr that has a different
slope than observed for carbonaceous chondrites. The offset between carbonaceous and non-carbonaceous meteorites in V-Cr isotope space is similar to differences also reported for
chromium, titanium, oxygen, molybdenum and ruthenium isotopes, which has been inferred to
reflect the presence in the early solar system of two physically separated reservoirs. The V
isotope composition of Earth is heavier than any meteorite measured to date. Therefore, V
isotopes support models of Earth accretion in which a significant portion of Earth was formed
from material that is not present in our meteorite collections.
Description:
This study was funded by NASA Emerging Worlds grant NNX16AD36G to SGN.
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
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