Constraining compositional proxies for Earth’s accretion and core formation through high pressure and high temperature Zn and S metal-silicate partitioning

Mahan, Brandon, Siebert, Julien, Blanchard, Ingrid, Borensztajn, Stephan, Badro, James, and Moynier, Frédéric (2018) Constraining compositional proxies for Earth’s accretion and core formation through high pressure and high temperature Zn and S metal-silicate partitioning. Geochimica et Cosmochimica Acta, 235. pp. 21-40.

[img] PDF (Published Version) - Published Version
Restricted to Repository staff only

View at Publisher Website: https://doi.org/10.1016/j.gca.2018.04.03...
 
1


Abstract

Zinc is a moderately volatile and slightly siderophile element, and therefore provides information into the timing and con- ditions of volatile element delivery to Earth as well as the redistribution of these elements during planetary differentiation. Specifically, due to its similar volatility with S, it has been assumed that the Earth and its source material maintain the same relative abundances of these elements, and therefore the same S/Zn ratio. In this study, we have conducted Zn metal-silicate partitioning experiments at pressures up to 81 GPa and temperatures up to 4100 K in diamond anvil cells, for two distinct silicate compositions (one pyrolitic, one basaltic) and varying S contents in order to characterize Zn metal-silicate partitioning as a function of these variables. These results have been input into Earth formation models where various parametric controls have been evaluated–namely source material, impactor size and volatile delivery–to determine plausible sets of conditions that can generate present-day bulk silicate Earth (BSE) Zn and S abundances. Modelling results indicate that to arrive at present- day BSE contents for Zn and S, and with core S contents of $2 wt% or less, the Earth likely accreted heterogeneously – initially from a volatile-depleted source material compositionally akin to the metal and silicate chondrules of CH chondrites, with later delivery of more volatile-rich material.

Item ID: 62755
Item Type: Article (Research - C1)
ISSN: 1872-9533
Keywords: metal-silicate partitioning, planetary differentiation, chondrule accretion, volatile elements
Copyright Information: © 2018 Elsevier Ltd. All rights reserved.
Funders: Sorbonne Paris Cité (SPC), Paris-IdF region SESAME (PIS), IDEX SPC, French National Research Agency (ANR), European Research Council (ERC)
Projects and Grants: SPC UnivEarthS Labex program, ANR-10-LABX-0023 and ANR-11-IDEX-0005-02, PIS grant No. 12015908, IDEX SPC PhD fellowship, ANR Project VolTerre, grant no. ANR-14-CE33-0017-01, ERC European Community’s Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement 207467 (DECore), ERC H2020 framework program/ERC grant agreement #637503 (Pristine), ANR chaire d’excellence Sorbonne Paris Cité
Date Deposited: 28 Jun 2020 20:06
FoR Codes: 04 EARTH SCIENCES > 0402 Geochemistry > 040202 Inorganic Geochemistry @ 50%
04 EARTH SCIENCES > 0402 Geochemistry > 040203 Isotope Geochemistry @ 50%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970104 Expanding Knowledge in the Earth Sciences @ 100%
Downloads: Total: 1
Last 12 Months: 1
More Statistics

Actions (Repository Staff Only)

Item Control Page Item Control Page