An Experimental Geochemistry Perspective on Earth's Core Formation

Siebert, J.; Shahar, Anat

doi:10.1002/9781118860359.ch6

Cited by 4 publications

(1 citation statement)

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“…It is depleted in the bulk silicate Earth (BSE) compared to the Sun and chondritic meteorites (Lodders & Fegley Jr, ; Palme & Jones, ; Palme & O'Neill, ), and this depletion is twofold in origin. It is due to volatility‐related processes, as attested to by the depletion of lithophile elements with similar T 50 (e.g., K, 1,006 K or Na, 958 K) in the BSE (Palme & O'Neill, ), and to being further depleted due to its partial sequestration into Earth's core (e.g., Siebert & Shahar, , and references therein). Sulfur is also a moderately volatile element but is more volatile than Cu with T 50 of around 700 K (Lodders, ).…”

Section: Introductionmentioning

confidence: 99%

Investigating Earth's Formation History Through Copper and Sulfur Metal‐Silicate Partitioning During Core‐Mantle Differentiation

et al. 2018

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Identifying extant materials that act as compositional proxies for Earth is key to understanding its accretion. Copper and sulfur are both moderately volatile elements; however, they display different geochemical behavior (e.g., phase affinities). Thus, individually and together, these elements provide constraints on the source material and conditions of Earth's accretion, as well as on the timing and evolution of volatile delivery to Earth. Here we present laser‐heated diamond anvil cell experiments at pressures up to 81 GPa and temperatures up to 4,100 K aimed at characterizing Cu metal‐silicate partitioning at conditions relevant to core‐mantle differentiation in Earth. Partitioning results have been combined with literature results for S in Earth formation modeling to constrain accretion scenarios that can arrive at present‐day mantle Cu and S contents. These modeling results indicate that the distribution of Cu and S in Earth may be the result of accretion largely from material(s) with Cu contents at or above chondritic values and S contents that are strongly depleted, such as that in bulk CH chondrites, and that the majority of Earth's mass (~3/4) accreted incrementally via pebble and/or planetesimal accretion.

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