Highly siderophile elements were stripped from Earth's mantle by iron sulfide segregation

Abstract

Highly siderophile elements (HSEs) are strongly depleted in the bulk silicate Earth (BSE) but are present in near-chondritic relative abundances. The conventional explanation is that the HSEs were stripped from the mantle by the segregation of metal during core formation but were added back in near-chondritic proportions by late accretion, after core formation had ceased. Here we show that metal-silicate equilibration and segregation during Earth's core formation actually increased HSE mantle concentrations because HSE partition coefficients are relatively low at the high pressures of core formation within Earth. The pervasive exsolution and segregation of iron sulfide liquid from silicate liquid (the "Hadean matte") stripped magma oceans of HSEs during cooling and crystallization, before late accretion, and resulted in slightly suprachondritic palladium/iridium and ruthenium/iridium ratios.

References in corpus (4)

• Water Delivery and Giant Impacts in the 'Grand Tack' Scenario
• Highly Siderophile Elements in the Earth's Mantle as a Clock for the Moon-forming Impact
• Lunar and Terrestrial Planet Formation in the Grand Tack Scenario
• On the formation and migration of giant planets in circumbinary discs

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• The Metal-Silicate Partitioning of Carbon During Earth's Accretion and its Distribution in the Early Solar System
• Early Bombardment of the Moon: Connecting the Lunar Crater Record to the Terrestrial Planet Formation
• Reduced atmospheres of post-impact worlds: The early Earth
• Metal-silicate partitioning of W and Mo and the role of carbon in controlling their abundances in the Bulk Silicate Earth
• The Effect of Inefficient Accretion on Planetary Differentiation
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• Constraining the Origin of Mars via Simulations of Multi-Stage Core Formation
• Evidence of a primordial isotopic gradient in the inner region of the solar protoplanetary disc