Iron isotope differences between Earth, Moon, Mars and Vesta as possible records of contrasted accretion mechanisms

Poitrasson, Franck; Halliday, A. N.; Lee, Der-Chuen; Levasseur, S.; Teutsch, Nadya

doi:10.1016/j.epsl.2004.04.032

Cited by 279 publications

(273 citation statements)

References 42 publications

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“…These results are consistent with other studies that have reported Fe-isotopic compositions of some of the Martian meteorites investigated in the present study (Zhu et al 2001;Poitrasson et al 2004;Weyer et al 2005). (Anand et al 2003).…”

Section: Resultssupporting

confidence: 83%

Searching for signatures of life on Mars: an Fe-isotope perspective

Anand

Russell

Blackhurst

et al. 2006

Phil. Trans. R. Soc. B

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Recent spacecraft and lander missions to Mars have reinforced previous interpretations that Mars was a wet and warm planet in the geological past. The role of liquid water in shaping many of the surface features on Mars has long been recognized. Since the presence of liquid water is essential for survival of life, conditions on early Mars might have been more favourable for the emergence and evolution of life. Until a sample return mission to Mars, one of the ways of studying the past environmental conditions on Mars is through chemical and isotopic studies of Martian meteorites. Over 35 individual meteorite samples, believed to have originated on Mars, are now available for labbased studies. Fe is a key element that is present in both primary and secondary minerals in the Martian meteorites. Fe-isotope ratios can be fractionated by low-temperature processes which includes biological activity. Experimental investigations of Fe reduction and oxidation by bacteria have produced large fractionation in Fe-isotope ratios. Hence, it is considered likely that if there is/were any form of life present on Mars then it might be possible to detect its signature by Fe-isotope studies of Martian meteorites. In the present study, we have analysed a number of Martian meteorites for their bulk-Fe-isotope composition. In addition, a set of terrestrial analogue material has also been analysed to compare the results and draw inferences. So far, our studies have not found any measurable Fe-isotopic fractionation in bulk Martian meteorites that can be ascribed to any lowtemperature process operative on Mars.

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Section: Resultssupporting

confidence: 83%

Searching for signatures of life on Mars: an Fe-isotope perspective

Anand

Russell

Blackhurst

et al. 2006

Phil. Trans. R. Soc. B

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“…In the past decade, the development of high-resolution Multi-Collector InductivelyCoupled-Plasma Mass-Spectrometers (MC-ICP-MS) has allowed measurements of iron isotope composition at high precision (Belshaw et al, 2000;Zhu et al, 2001;Weyer and Schwieters, 2003;Dauphas et al, 2009b;Millet et al, 2012). Following this improvement, small yet resolvable iron isotopic variations in igneous rocks have been discovered (Poitrasson et al, 2004;Weyer et al, 2005;Schoenberg and von Blanckenburg, 2006;Weyer and Ionov, 2007;Heimann et al, 2008;Teng et al, 2008Teng et al, , 2011Dauphas et al, 2009a;Weyer and Seitz, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…Three mechanisms have been proposed to explain this difference: (1) Planetary accretion: Heavy iron isotopes were enriched on the Earth and Moon by evaporative kinetic isotope fractionation during the giant impact that formed the Moon (Poitrasson et al, 2004). In this context, one of the difficulties is to explain why potassium, which is highly volatile, is not isotopically fractionated in the EarthMoon system (Humayun and Clayton, 1995).…”

Section: Introductionmentioning

confidence: 99%

“…Mid-ocean ridge basalts (MORBs), oceanic island basalts (OIBs), and continental basalts are enriched in heavy iron isotopes by $+0.1& when compared to chondrites; while martian and 4-Vesta (HED) meteorites all have similar iron isotope compositions to chondrites (Poitrasson et al, 2004;Weyer et al, 2005;Anand et al, 2006;Schoenberg and von Blanckenburg, 2006;Craddock and Dauphas, 2011). Three mechanisms have been proposed to explain this difference: (1) Planetary accretion: Heavy iron isotopes were enriched on the Earth and Moon by evaporative kinetic isotope fractionation during the giant impact that formed the Moon (Poitrasson et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

“…In this context, one of the difficulties is to explain why potassium, which is highly volatile, is not isotopically fractionated in the EarthMoon system (Humayun and Clayton, 1995). Poitrasson et al (2004) proposed that Fe was evaporated from core material as metal while K was evaporated as oxides. In that case, Fe would be more volatile than K and could be isotopically more fractionated.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Iron isotope fractionation in planetary crusts

Wang

Moynier

Dauphas

et al. 2012

Geochimica et Cosmochimica Acta

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We present new high precision iron isotope data (d 56 Fe vs. IRMM-014 in per mil) for four groups of achondrites: one lunar meteorite, 11 martian meteorites, 32 howardite-eucrite-diogenite meteorites (HEDs), and eight angrites. Angrite meteorites are the only planetary materials, other than Earth/Moon system, significantly enriched in the heavy isotopes of Fe compared to chondrites (by an average of +0.12& in d 56 Fe). While the reason for such fractionation is not completely understood, it might be related to isotopic fractionation by volatilization during accretion or more likely magmatic differentiation in the angrite parent-body. We also report precise data on martian and HED meteorites, yielding an average d 56 Fe of 0.00 ± 0.01&. Stannern-trend eucrites are isotopically heavier by +0.05& in d 56 Fe than other eucrites. We show that this difference can be ascribed to the enrichment of heavy iron isotopes in ilmenite during igneous differentiation. Preferential dissolution of isotopically heavy ilmenite during remelting of eucritic crust could have generated the heavy iron isotope composition of Stannern-trend eucrites. This supports the view that Stannern-trend eucrites are derived from main-group eucrite source magma by assimilation of previously formed asteroidal crust.These new results show that iron isotopes are not only fractionated in terrestrial and lunar basalts, but also in two other differentiated planetary crusts. We suggest that igneous processes might be responsible for the iron isotope variations documented in planetary crusts.

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Polyamorphic Transformations in Fe‐Ni‐C Liquids: Implications for Chemical Evolution of Terrestrial Planets

et al. 2017

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During the formation of the Earth's core, the segregation of metallic liquids from silicate mantle should have left behind evident geochemical imprints on both the mantle and the core. Some distinctive geochemical signatures of the mantle‐derived rocks likely own their origin to the metal‐silicate differentiation of the primitive Earth, setting our planet apart from undifferentiated meteorites as well as terrestrial planets or moons isotopically and compositionally. Understanding the chemical evolution of terrestrial planetary bodies requires knowledge on properties of both liquid iron alloys and silicates equilibrating under physicochemical conditions pertinent to the deep magma ocean. Here we report experimental and computational results on the pressure‐induced structural evolution of iron‐nickel liquids alloyed with carbon. Our X‐ray diffraction experiments up to 7.3 gigapascals (GPa) demonstrate that Fe‐Ni (Fe90Ni10) liquids alloyed with 3 and 5 wt % carbon undergo a polyamorphic liquid structure transition at approximately 5 GPa. Corroborating the experimental observations, our first‐principles molecular dynamic calculations reveal that the structural transitions result from the marked prevalence of three‐atom face‐sharing polyhedral connections in the liquids at >5 GPa. The structure and polyamorphic transitions of liquid iron‐nickel‐carbon alloys govern their physical and chemical properties and may thus cast fresh light on the chemical evolution of terrestrial planets and moons.

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Iron isotope differences between Earth, Moon, Mars and Vesta as possible records of contrasted accretion mechanisms

Cited by 279 publications

References 42 publications

Searching for signatures of life on Mars: an Fe-isotope perspective

Searching for signatures of life on Mars: an Fe-isotope perspective

Iron isotope fractionation in planetary crusts

Polyamorphic Transformations in Fe‐Ni‐C Liquids: Implications for Chemical Evolution of Terrestrial Planets

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