Ruthenium isotopic fractionation in primitive achondrites: Clues to the early stages of planetesimal melting

Hopp, Timo; Kleine, T.

doi:10.1016/j.gca.2021.03.016

Cited by 6 publications

(4 citation statements)

References 63 publications

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“…As such, determining the potential Ni stable isotope difference between ureilites and chondrites could shed light on the core formation effect on Ni isotope fractionation, and further constrain the terrestrial core formation (Klaver et al., 2020). A similar approach using ureilites had been taken to study the effect of core formation on highly siderophile elements (Creech, Baker, Handler, et al., 2017; Creech, Moynier, & Bizzarro, 2017; Hopp & Kleine, 2021). Additionally, the size of UPB is smaller than Earth (Nabiei et al., 2018; Nestola et al., 2020; Schiller et al., 2018), and the effect of isotope fractionation during core formation for the UPB should be larger than that of the Earth due to higher temperature in the core‐mantle boundary of larger bodies.…”

Section: Introductionmentioning

confidence: 99%

Nickel and Chromium Stable Isotopic Composition of Ureilites: Implications for the Earth's Core Formation and Differentiation of the Ureilite Parent Body

Zhu

Barrat

Yamaguchi

et al. 2022

Geophysical Research Letters

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We report the first Ni and Cr stable isotope data for ureilite meteorites that are the mantle residue of a carbon‐rich differentiated planet. Ureilites have similar Ni stable isotope compositions as chondrites, suggesting that the core‐mantle differentiation of ureilite parent body (UPB) did not fractionate Ni isotopes. Since the size of Earth is potentially larger than that of UPB; with diameter >690 km), resulting in higher temperatures at the core‐mantle boundary of Earth, it can be predicted that the terrestrial core formation may not directly cause Ni stable isotope fractionation. On the other hand, we also report high‐precision Cr stable isotope composition of ureilites, including one ureilitic trachyandesite (ALM‐A) that is enriched in lighter Cr stable isotopes relative to the main‐group ureilites, which suggests that the partial melting occurred on UPB. The globally heavy Cr in the UPB compared to chondrites can be caused by sulfur‐rich core formation processes.

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Section: Introductionmentioning

confidence: 99%

Nickel and Chromium Stable Isotopic Composition of Ureilites: Implications for the Earth's Core Formation and Differentiation of the Ureilite Parent Body

Zhu

Barrat

Yamaguchi

et al. 2022

Geophysical Research Letters

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“…The extraction of S-rich Fe-Ni-S melts cannot easily explain the observed Ru isotopic fractionation with reasonable degrees of melt extraction. However, the extraction of S-poor metallic melts at higher temperatures can produce the heavier δ 102/99 Ru values of primitive achondrites with realistic degrees of melt extraction(Hopp and Kleine, 2021). Thus, the results from the S-rich experiments reported here are likely not directly applicable to the main driver of isotopic fractionation in primitive achondrites, i.e.…”

mentioning

confidence: 78%

“…Nevertheless, they provide evidence for variable extraction of S-rich and S-poor Fe-Ni-S melts (Day et al, 2012;Goodrich et al, 2013;Dhaliwal et al, 2017;Day et al, 2019). Hopp and Kleine (2021)…”

Section: Implications For Ru Isotope Fractionation In Natural Fe-fes Systemsmentioning

confidence: 99%

Experimental investigation of Ru isotope fractionation between metal, silicate and sulfide melts

et al. 2021

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“…Acapulcoites and lodranites may record processes of early metal and low-fraction (< 2-7%) silicate melt loss (Mittlefehldt et al 1996;Dhaliwal et al 2019). As noted by Hopp and Kleine (2021), complex patterns of S-poor and S-rich metallic veins, heterogeneous distribution of FeNi metal, and HSE systematics in several primitive achondrite groups indicate successive segregation and redistribution of both S-rich and S-free metallic liquids prior to silicate melting, and a complex series of differentiation processes. Wang et al (2014) suggested that ungrouped feldspar-rich achondrites represent products of low-degree silicate melting, with Fe isotope systematics inferred to represent an earlier period of at least localised FeS-rich liquid accumulation.…”

Section: Introductionmentioning

confidence: 91%

The Geochemical Legacy of Low-Temperature, Percolation-Driven Core Formation in Planetesimals

Bromiley

2023

Earth Moon Planets

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Mechanisms for core formation in differentiated bodies in the early solar system are poorly constrained. At temperatures below those required to extensively melt planetesimals, core formation could have proceeded via percolation of metallic liquids. Although there is some geochemical data to support such ‘low-temperature’ segregation, experimental studies and simulations suggest that percolation-driven segregation might have only contributed to core formation in a proportion of fully-differentiated bodies. Here, the effects low-temperature core-formation on elemental compositions of planetesimal cores and mantles are explored. Immiscibility of Fe-rich and FeS-rich liquids will occur in all core-formation models, including those involving large fraction silicate melting. Light element content of cores (Si, O, C, P, S) depends on conditions under which Fe-rich and FeS-rich liquids segregated, especially pressure and oxygen fugacity. The S contents of FeS-rich liquids significantly exceed eutectic compositions in Fe–Ni–S systems and cannot be reconciled with S-contents of parent bodies to magmatic iron meteorites. Furthermore, there is limited data on trace element partitioning between FeS-rich and Fe-rich phases, and solid/melt partitioning models cannot be readily applied to FeS-rich liquids. Interaction of metallic liquids with minor phases stable up to low fraction silicate melting could provide a means for determining the extent of silicate melting prior to initiation of core-formation. However, element partitioning in most core-formation models remains poorly constrained, and it is likely that conditions under which segregation of metallic liquid occurred, especially oxygen fugacity and pressure, had as significant a control on planetesimal composition as segregation mechanisms and extent of silicate melting.

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Ruthenium isotopic fractionation in primitive achondrites: Clues to the early stages of planetesimal melting

Cited by 6 publications

References 63 publications

Nickel and Chromium Stable Isotopic Composition of Ureilites: Implications for the Earth's Core Formation and Differentiation of the Ureilite Parent Body

Nickel and Chromium Stable Isotopic Composition of Ureilites: Implications for the Earth's Core Formation and Differentiation of the Ureilite Parent Body

Experimental investigation of Ru isotope fractionation between metal, silicate and sulfide melts

The Geochemical Legacy of Low-Temperature, Percolation-Driven Core Formation in Planetesimals

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