Calcium Isotope Composition of Meteorites, Earth, and Mars

Simon, Justin I.; DePaolo, Donald J.; Moynier, Frédéric

doi:10.1088/0004-637x/702/1/707

Cited by 148 publications

(186 citation statements)

References 81 publications

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“…These results are consistent with the previous work (Jungck et al, 1984;Niederer and Papanastassiou, 1984), who also observed 48 Ca excess and no 40 Ca or 43 Ca anomalies in refractory inclusions from Allende and Leoville. In contrast, Simon et al (2009) reported up to 2 e units 40 Ca excess in two refractory inclusions from Allende, and a subsequent study reported that these two refractory inclusions also have 48 Ca excess (Moynier et al, 2010). The level of 40 Ca excess reported by Simon et al (2009) well exceeds the analytical uncertainty of e 40/44 Ca in our study, as well as those of Jungck et al (1984) and Niederer and Papanastassiou (1984).…”

Section: Nucleosynthetic Anomalies In Ca Isotopessupporting

confidence: 53%

“…We use mass-independent Ca isotopic effects to measure the nucleosynthetic isotopic anomalies in extraterrestrial materials, such as refractory inclusions and chondrites (e.g., Simon et al, 2009;Chen et al, 2011;Lee et al, 2011). In this case, the 40 Ca/ 44 Ca, 43 Ca/ 44 Ca and 48 Ca/ 44 Ca ratios of the samples and the standard are internally normalized (indicated by N) to 42 Ca/ 44 Ca = 0.31221 (Russell et al, 1978) using an exponential law to correct for both instrumental fractionation and fractionation intrinsic to the sample.…”

Section: Group I N-group Iimentioning

confidence: 99%

“…The 42 Ca/ 44 Canormalization was chosen because, in general, there are no nucleosynthetic isotopic anomalies on 42 Ca or 44 Ca (e.g., Jungck et al, 1984;Niederer and Papanastassiou, 1984;Simon et al, 2009;Lee et al, 2011). Note, however, that Chen et al (2011) recently reported an example of nucleosynthetic isotopic anomalies on 42 …”

Section: Group I N-group Iimentioning

confidence: 99%

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Calcium isotopic ratios and rare earth element abundances in refractory inclusions from the Allende CV3 chondrite

Huang

Farkaš

et al. 2012

Geochimica et Cosmochimica Acta

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Section: Nucleosynthetic Anomalies In Ca Isotopessupporting

confidence: 53%

Section: Group I N-group Iimentioning

confidence: 99%

See 1 more Smart Citation

Calcium isotopic ratios and rare earth element abundances in refractory inclusions from the Allende CV3 chondrite

Huang

Farkaš

et al. 2012

Geochimica et Cosmochimica Acta

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“…The Moon has an isotopic composition that is identical to the silicate mantle of the Earth within the relatively tight analytical constraints provided by modern instrumentation for oxygen (Weichert et al 2001;Kohl et al 2015), silicon (Armytage et al 2012), calcium (Simon et al 2009) magnesium (Sedaghatpour et al 2013), iron (Moynier et al 2006), titanium (Zhang et al 2012), strontium (Moynier et al 2010a) and chromium (Lugmair and Shukolyukov 1998) but it has had a totally different geochemical development. The similarity in oxygen isotopes seems particularly significant as O 2-is a large anion and the packing of oxygen anions largely controls the abundance of other elements in silicates.…”

Section: The Origin Of the Moon: Current Ideasmentioning

confidence: 99%

The Moon

Taylor

2015

Acta Geochim

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Recent geochemical and geophysical data from the Moon enable a revision of earlier interpretations regarding lunar origin, structure and bulk composition. Earth and Moon show many similarities among their isotopic compositions, but they have evolved in totally dissimilar ways, probably related to the deficiency of water and volatile elements in the Moon as well as the vast differences in size and internal pressure. Some global geochemical differences from the Earth such as volatile depletion based on K/U ratios have been established. However, all current lunar samples come from differentiated regions, making the establishment of a bulk composition more reliant on bulk geophysical properties or isotopic similarities; it remains unclear how the latter arose or relate to whole Moon composition. The lack of fractionation effects among the refractory and super-refractory elements indicates that the proto-lunar material seems unlikely to have been vaporized while the presence of volatile elements may place lower limits on proto-lunar temperatures. The apparent lack of geochemical evidence of an impacting body enables other possible impactors, such as comets, to be considered. Although the origin of the Moon remains currently unknown, it is generally believed that the Moon originated as the result of a giant impact on the Earth.

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“…As we obtain more information from Solar System materials regarding compositional or isotopic zoning, the interaction between chemistry and dynamics will be more fruitful. For example, isotopes of the refractory element Ca exhibit no variation for many differentiated bodies in the inner Solar System (75). Similarly, the volatile element N exhibits a narrow range in isotopic composition for all known planetary materials, yet this isotopic composition is distinct from the compositions of the Sun and comets (76).…”

Section: Future and Unresolvedmentioning

confidence: 99%

Terrestrial planet formation

Righter

O’Brien

2011

Proc. Natl. Acad. Sci. U.S.A.

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Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (∼10 6 y), followed by planetesimals to embryos (lunar to Marssized objects; few × 10 6 y), and finally embryos to planets (10 7 -10 8 y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids.H ow terrestrial planets grew out of the solar nebula has long been a topic of interest, and is still being pursued by a combination of studies involving samples of terrestrial and extraterrestrial materials, as well as computational models. Early nebular models by Descartes, Kant, and Laplace proposed that the planets formed from the solar nebula by various mechanisms such as vortices (analogous to spinning galaxies), or by shedding rings, but all of these general concepts failed to produce fundamental features of our Solar System (e.g., ref. 1). Subsequent models included homogeneous accretion (e.g., refs. 2, 3), in which the planets condensed from the nebula and were composed of homogeneous material that differentiated internally, and heterogeneous accretion (4), in which planets grew like layer cakes as the phases condensing out of the nebula changed with decreasing temperature. The purpose of this review is to elucidate how new samples, experiments, and modeling are contributing to a more thorough and sophisticated understanding of the many factors that helped to shape our inner Solar System ( Fig. 1; see SI Text) and specifically the Earth. We also highlight areas where more extensive work is necessary or more samples are needed to better constrain our models, and where physical and chemical constraints may benefit from combined approaches. CompositionPrimitive chondrites were likely the building blocks for terrestrial planets, with bulk compositions similar to the Sun, but with differing oxygen fugacities (Fig. S1) and other chemical characteristics such as volatile element depletions (5; SI Text, Fig. S2). In a...

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Calcium Isotope Composition of Meteorites, Earth, and Mars

Cited by 148 publications

References 81 publications

Calcium isotopic ratios and rare earth element abundances in refractory inclusions from the Allende CV3 chondrite

Calcium isotopic ratios and rare earth element abundances in refractory inclusions from the Allende CV3 chondrite

The Moon

Terrestrial planet formation

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