Rai, N;
Downes, H;
Smith, C;
(2020)
Ureilite meteorites provide a new model of early planetesimal formation and destruction.
Geochemical Perspectives Letters
, 14
pp. 20-25.
10.7185/geochemlet.2018.
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Abstract
Ureilite meteorites are ultramafic rocks derived from parts of the depleted silicate mantle of their parent planetesimal. We used Monte Carlo modelling to explain the observed array of oxygen isotopes and major element chemistry shown by bulk ureilites, after restoration of their missing core and silicate melt components. Despite using a wide range of primitive nebular material, our modelling shows that only a combination of proxy material resembling Allende-type FeO-rich and MgO-rich chondrules, can account for the ureilite oxygen isotope trend and the reconstructed ureilite major element chemistry. Our model predicts formation of a radial gradient in major elements and oxygen isotopes within the planetesimal, with a more Mg-rich silicate interior and a more Fe-rich silicate exterior. Temperatures recorded by ureilites were not high enough to form a magma ocean but were sufficiently high to form a metallic core and silicate melts. The ureilite parent planetesimal was then disrupted by impact. Re-accretion of the outer layers of more Fe-rich silicate material, at the expense of the more MgO-rich material and the core, explains the observed distribution of bulk rock and mineral compositions.
| Type: | Article |
|---|---|
| Title: | Ureilite meteorites provide a new model of early planetesimal formation and destruction |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.7185/geochemlet.2018 |
| Publisher version: | https://doi.org/10.7185/geochemlet.2018 |
| Language: | English |
| Additional information: | This work is distributed under the Creative Commons Attribution Non- Commercial No-Derivatives 4.0 License, which permits unrestricted distribution provided the original author and source are credited. The material may not be adapted (remixed, transformed or built upon) or used for commercial purposes without written permission from the author. Additional information is available at http://www. geochemicalperspectivesletters.org/copyright-and-permissions. See: https://creativecommons.org/licenses/by-nc-nd/4.0/ |
| Keywords: | Science & Technology, Physical Sciences, Geochemistry & Geophysics, ISOTOPE FRACTIONATION, SIDEROPHILE ELEMENTS, IMPACT, DIFFERENTIATION, GEOCHEMISTRY, SEGREGATION, SYSTEMATICS, CHONDRULES, VOLCANISM, INSIGHTS |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10119661 |
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