Nd isotope variation between the Earth–Moon system and enstatite chondrites

Johnston, Shelby; Brandon, A. D.; McLeod, Claire; Rankenburg, Kai; Becker, Harry; Copeland, Peter

doi:10.1038/s41586-022-05265-0

Cited by 20 publications

(8 citation statements)

References 49 publications

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“…That is, early Earth probably contains a significant amount of oldhamite. The Earth–Moon precursor materials with oldhamite enrichment could well explain the Sm/Nd ratio and Nd isotope features of Earth and the Moon [ 62 ]. The upper limit of the lg f o 2 range of Earth's atmosphere before GOE is from −7.6 to −6.0 (Fig.…”

Section: Discussionmentioning

confidence: 99%

Oldhamite: a new link in upper mantle for C–O–S–Ca cycles and an indicator for planetary habitability

Liu,

Chou,

Chen

et al. 2023

National Science Review

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In the solar system, oldhamite (CaS) is generally considered to be formed by the condensation of solar nebula gas. Enstatite chondrites, one of the most important repositories of oldhamite, are believed to be the representative of the material which formed Earth. Thus, the formation mechanism and the evolution process of oldhamite are of great significance to the deep understanding of the solar nebula, meteorites, the origin of Earth, and the C-O-S-Ca cycles of Earth. Until now, oldhamite has not been reported to occur in mantle rock. However, here we show the formation of oldhamite through the reaction between sulfide-bearing orthopyroxenite and molten CaCO3 at 1.5 GPa/1510 K, 0.5 GPa/1320 K, and 0.3 GPa/1273 K. Importantly, this reaction occurs at oxygen fugacities within the range of upper mantle conditions, 6 orders of magnitude higher than that of the solar nebula mechanism. Oldhamite is easily oxidized to CaSO4 or hydrolyzed to produce calcium hydroxide. Low oxygen fugacity of magma, extremely low oxygen content of the atmosphere, and the lack of a large amount of liquid water on the planet's surface are necessary for the widespread existence of oldhamite on the surface of a planet; otherwise, anhydrite or gypsum will exist in large quantities. Oldhamites may exist in the upper mantle beneath mid-ocean ridges. Additionally, oldhamites may have been a contributing factor to the early Earth's atmospheric hypoxia environment, and the transient existence of oldhamites during the interaction between reducing sulfur-bearing magma and carbonate could have had an impact on the changes in atmospheric composition during the Permian-Triassic Boundary.

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Section: Discussionmentioning

confidence: 99%

Oldhamite: a new link in upper mantle for C–O–S–Ca cycles and an indicator for planetary habitability

Liu,

Chou,

Chen

et al. 2023

National Science Review

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“…That is, Earth's accreting materials originate from both CC (carbonaceous) and NC (noncarbonaceous) reservoirs, which is also supported by Earth's nucleosynthetic K and Zn isotope anomalies (32)(33)(34)(35). In addition, the massindependent Mo and Nd isotopic composition of Earth's mantle may reflect a mixture between NC and unsampled s-process-enriched CC material compared to known chondrites (36)(37)(38). In contrast, Schiller et al (39) found that the mass-independent μ 54 Fe of Earth's mantle overlaps with the value of CI chondrite but is lower than other chondrites, indicating that most of Fe in Earth's mantle derived from inward-drifting CI-like material.…”

Section: Discussionmentioning

confidence: 95%

“…That is, Earth’s accreting materials originate from both CC (carbonaceous) and NC (noncarbonaceous) reservoirs, which is also supported by Earth’s nucleosynthetic K and Zn isotope anomalies ( 32 – 35 ). In addition, the mass-independent Mo and Nd isotopic composition of Earth’s mantle may reflect a mixture between NC and unsampled s -process–enriched CC material compared to known chondrites ( 36 – 38 ). In contrast, Schiller et al.…”

Section: Discussionmentioning

confidence: 99%

Chalcogen isotopes reveal limited volatile contribution from late veneer to Earth

Wang,

Walter,

Brodholt

et al. 2023

Sci. Adv.

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The origin of Earth’s volatile elements is highly debated. Comparing the chalcogen isotope ratios in the bulk silicate Earth (BSE) to those of its possible building blocks, chondritic meteorites, allows constraints on the origin of Earth’s volatiles; however, these comparisons are complicated by potential isotopic fractionation during protoplanetary differentiation, which largely remains poorly understood. Using first-principles calculations, we find that core-mantle differentiation does not notably fractionate selenium and tellurium isotopes, while equilibrium evaporation from early planetesimals would enrich selenium and tellurium in heavy isotopes in the BSE. The sulfur, selenium, and tellurium isotopic signatures of the BSE reveal that protoplanetary differentiation plays a key role in establishing most of Earth’s volatile elements, and a late veneer does not substantially contribute to the BSE’s volatile inventory.

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“…A later differentiation at 4.40 Ga would require a lower 147 Sm/ 144 Nd ratio of 0.175 to evolve to μ 142 Nd = −10. As illustrated on Figure 3, derivation at 4.40 Ga from a slightly super-chondritic BSE with initial μ 142 Nd = −7.6 (average value proposed by Frossard et al, 2022 andJohnston et al, 2022) would increase the required 147 Sm/ 144 Nd ratio to 0.185 in order to produce the same μ 142 Nd of −10.…”

Section: Discussionmentioning

confidence: 97%

Rare evidence for the existence of a Hadean enriched mantle reservoir

Garcia,

O’Neil,

Dantas

2023

Geochem. Persp. Let.

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Short lived isotopic systems can help unravel the complex early differentiation history of the Earth's mantle. Excesses in neodymium-142 ( 142 Nd) measured in several occurrences of Archean mantle-derived rocks, compared to the modern upper mantle, imply the formation of an early depleted mantle in the Hadean. However, the existence of a complementary enriched reservoir, which should have also stemmed from such early differentiation event, remains equivocal. New data on 3.4 billion year old amphibolites from the São José do Campestre Massif, NE Brazil, show well resolved 142 Nd deficits compared to the modern upper mantle, down to −14.1 ppm. This provides the first clear evidence for an early enriched mantle source, which may represent the missing concomitant reservoir complementary to Earth's early depleted mantle.

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Nd isotope variation between the Earth–Moon system and enstatite chondrites

Cited by 20 publications

References 49 publications

Oldhamite: a new link in upper mantle for C–O–S–Ca cycles and an indicator for planetary habitability

Oldhamite: a new link in upper mantle for C–O–S–Ca cycles and an indicator for planetary habitability

Chalcogen isotopes reveal limited volatile contribution from late veneer to Earth

Rare evidence for the existence of a Hadean enriched mantle reservoir

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