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Liu B, Johansen A, Lambrechts M, Bizzarro M, Haugbølle T. Natural separation of two primordial planetary reservoirs in an expanding solar protoplanetary disk. SCIENCE ADVANCES 2022; 8:eabm3045. [PMID: 35452282 PMCID: PMC9032962 DOI: 10.1126/sciadv.abm3045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 03/08/2022] [Indexed: 06/14/2023]
Abstract
Meteorites display an isotopic composition dichotomy between noncarbonaceous (NC) and carbonaceous (CC) groups, indicating that planetesimal formation in the solar protoplanetary disk occurred in two distinct reservoirs. The prevailing view is that a rapidly formed Jupiter acted as a barrier between these reservoirs. We show a fundamental inconsistency in this model: If Jupiter is an efficient blocker of drifting pebbles, then the interior NC reservoir is depleted by radial drift within a few hundred thousand years. If Jupiter lets material pass it, then the two reservoirs will be mixed. Instead, we demonstrate that the arrival of the CC pebbles in the inner disk is delayed for several million years by the viscous expansion of the protoplanetary disk. Our results support the hypothesis that Jupiter formed in the outer disk (>10 astronomical units) and allowed a considerable amount of CC material to pass it and become accreted by the terrestrial planets.
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Affiliation(s)
- Beibei Liu
- Zhejiang Institute of Modern Physics, Department of Physics and Zhejiang University–Purple Mountain Observatory Joint Research Center for Astronomy, Zhejiang University, 38 Zheda Road, Hangzhou 310027, China
- Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Box 43, 22100 Lund, Sweden
| | - Anders Johansen
- Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Box 43, 22100 Lund, Sweden
- Center for Star and Planet Formation, GLOBE Institute, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen, Denmark
| | - Michiel Lambrechts
- Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Box 43, 22100 Lund, Sweden
- Center for Star and Planet Formation, GLOBE Institute, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen, Denmark
| | - Martin Bizzarro
- Center for Star and Planet Formation, GLOBE Institute, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen, Denmark
| | - Troels Haugbølle
- Niels Bohr Institute, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen, Denmark
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Abstract
The age of iron meteorites implies that accretion of protoplanets began during the first millions of years of the solar system. Due to the heat generated by 26Al decay, many early protoplanets were fully differentiated with an igneous crust produced during the cooling of a magma ocean and the segregation at depth of a metallic core. The formation and nature of the primordial crust generated during the early stages of melting is poorly understood, due in part to the scarcity of available samples. The newly discovered meteorite Erg Chech 002 (EC 002) originates from one such primitive igneous crust and has an andesite bulk composition. It derives from the partial melting of a noncarbonaceous chondritic reservoir, with no depletion in alkalis relative to the Sun's photosphere and at a high degree of melting of around 25%. Moreover, EC 002 is, to date, the oldest known piece of an igneous crust with a 26Al-26Mg crystallization age of 4,565.0 million years (My). Partial melting took place at 1,220 °C up to several hundred kyr before, implying an accretion of the EC 002 parent body ca. 4,566 My ago. Protoplanets covered by andesitic crusts were probably frequent. However, no asteroid shares the spectral features of EC 002, indicating that almost all of these bodies have disappeared, either because they went on to form the building blocks of larger bodies or planets or were simply destroyed.
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Siron G, Fukuda K, Kimura M, Kita NT. New constraints from 26Al- 26Mg chronology of anorthite bearing chondrules in unequilibrated ordinary chondrites. GEOCHIMICA ET COSMOCHIMICA ACTA 2021; 293:103-126. [PMID: 35001941 PMCID: PMC8740609 DOI: 10.1016/j.gca.2020.10.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
26Al-26Mg ages were determined for 14 anorthite-bearing chondrules from five different unequilibrated ordinary chondrites (UOCs) with low petrologic subtypes (3.00-3.05). In addition, oxygen three isotopes of these chondrules were also measured. The selected chondrules are highly depleted in alkali elements, and anorthite is the only mesostasis phase, though they show a range of mafic mineral compositions (Mg# 76-97 mole%) that are representative of chondrules in UOCs. The mean ∆17O values in these chondrules range from -0.44 ± 0.23‰ to 0.49 ± 0.15‰, in good agreement with previous studies of plagioclase-bearing chondrules from UOCs. Anorthite in all chondrules exhibit resolvable excess 26Mg (> 1.0 ± 0.4‰). Their inferred (27Al/26Al)0 range from (6.3 ± 0.7)×10-6 to (8.9 ± 0.3)×10-6 corresponding to a timescale for chondrule formation of 1.8 ± 0.04 Ma to 2.16 ± 0.12/0.11 Ma after CAIs using a canonical (27Al/26Al)0 value of 5.25×10-5. The ages from six chondrules in LL chondrites are restricted to between 1.8 Ma and 1.9 Ma, whereas eight chondrules in L chondrites show ages from 1.8 Ma to 2.2 Ma, including three chondrules at ~2.0 Ma and two chondrules at ~2.15 Ma. The inferred chondrule formation ages from this study are at the peak of those previously determined for UOC chondrules, though with much shorter durations. This is potentially due to the time difference between formation of anorthite-bearing chondrules and typical UOC chondrules with alkali-rich compositions. Alternatively, younger chondrules ages in previous studies could have been the result of disturbance to the Al-Mg system in glassy mesostasis even at the low degree of thermal metamorphism in the parent bodies. Nevertheless, the high precision ages from this study (with uncertainties from 0.04 Ma to 0.15 Ma) indicate that there was potentially more than one chondrule forming event represented in the studied population. Considering data from LL chondrites only, the restricted duration (≤0.1 Ma) of chondrule formation ages suggests an origin in high density environments that subsequently lead to parent body formation. However, the unusually low alkali contents of the studied chondrules compared to common alkali-rich chondrules could also represent earlier chondrule formation events under relatively lower dust densities in the disk. Major chondrule forming events for UOCs might have postdated or concurrent with the younger anorthite-bearing chondrule formation at 2.15 Ma after CAIs, which are very close to the timing of accretion of ordinary chondrite parent bodies that are expected from thermal evolution of ordinary chondrite parent bodies.
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Affiliation(s)
- Guillaume Siron
- WiscSIMS, Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Kohei Fukuda
- WiscSIMS, Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Makoto Kimura
- National Institute of Polar Research, Meteorite Research Center, Midoricho 10-3, Tachikawa, Tokyo 190-8518, Japan
| | - Noriko T Kita
- WiscSIMS, Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, USA
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Ganino C, Libourel G. Fumarolic-like activity on carbonaceous chondrite parent body. SCIENCE ADVANCES 2020; 6:6/27/eabb1166. [PMID: 32937456 PMCID: PMC7458441 DOI: 10.1126/sciadv.abb1166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 05/20/2020] [Indexed: 06/11/2023]
Abstract
Comparative planetology studies are key for understanding the main processes driving planetary formation and evolution. None have been yet applied to pristine asteroids formed in the solar protoplanetary disk, mainly because of their comminution during their 4.5-billion-year collisional lifetime. From remarkable textural, mineralogical, chemical, and thermodynamic similarities, we show that the high-temperature Kudryavy volcano fumarolic environment from Kurile Islands is a likely proxy of the Fe-alkali-halogen metasomatism on the CV and CO carbonaceous chondrite parent bodies. Ca-Fe-rich and Na-Al-Cl-rich secondary silicates in CV and CO chondrites are, thus, inferred to be fumarolic-like incrustations that precipitate from hot and reduced hydrothermal vapors after interactions with the wallrocks during buoyancy-driven Darcy flow percolation. These vapors may originate from the progressive heating and devolatilization of a chondritic protolith on their parent body or are remnant of the cooling of residual local nebular gases at the time of their primary planetesimal accretion.
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Affiliation(s)
- Clément Ganino
- Université Côte d'Azur, OCA, CNRS, IRD, Géoazur, 250 rue Albert Einstein, Sophia-Antipolis, 06560 Valbonne, France.
| | - Guy Libourel
- Université Côte d'Azur, OCA, CNRS, Lagrange, Boulevard de l'Observatoire, CS 34229, 06304 Nice Cedex 4, France
- Hawai'i Institute of Geophysics and Planetology, School of Ocean, Earth Science and Technology, University of Hawai'i at Mānoa, Honolulu, HI i 96821, USA
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Edwards GH, Blackburn T. Accretion of a large LL parent planetesimal from a recently formed chondrule population. SCIENCE ADVANCES 2020; 6:eaay8641. [PMID: 32494606 PMCID: PMC7159928 DOI: 10.1126/sciadv.aay8641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 01/22/2020] [Indexed: 06/11/2023]
Abstract
Chondritic meteorites, derived from asteroidal parent bodies and composed of millimeter-sized chondrules, record the early stages of planetary assembly. Yet, the initial planetesimal size distribution and the duration of delay, if any, between chondrule formation and chondrite parent body accretion remain disputed. We use Pb-phosphate thermochronology with planetesimal-scale thermal models to constrain the minimum size of the LL ordinary chondrite parent body and its initial allotment of heat-producing 26Al. Bulk phosphate 207Pb/206Pb dates of LL chondrites record a total duration of cooling ≥75 Ma, with an isothermal interior that cools over ≥30 Ma. Since the duration of conductive cooling scales with parent body size, these data require a ≥150-km radius parent body and a range of bulk initial 26Al/27Al consistent with the initial 26Al/27Al ratios of constituent LL chondrules. The concordance suggests that rapid accretion of a large LL parent asteroid occurred shortly after a major chondrule-forming episode.
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Gregory T, Luu TH, Coath CD, Russell SS, Elliott T. Primordial formation of major silicates in a protoplanetary disc with homogeneous 26Al/ 27Al. SCIENCE ADVANCES 2020; 6:eaay9626. [PMID: 32195348 PMCID: PMC7065882 DOI: 10.1126/sciadv.aay9626] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 12/11/2019] [Indexed: 06/10/2023]
Abstract
Understanding the spatial variability of initial 26Al/27Al in the solar system, i.e., (26Al/27Al)0, is of prime importance to meteorite chronology, planetary heat production, and protoplanetary disc mixing dynamics. The (26Al/27Al)0 of calcium-aluminum-rich inclusions (CAIs) in primitive meteorites (~5 × 10-5) is frequently assumed to reflect the (26Al/27Al)0 of the entire protoplanetary disc, and predicts its initial 26Mg/24Mg to be ~35 parts per million (ppm) less radiogenic than modern Earth (i.e., Δ'26Mg0 = -35 ppm). Others argue for spatially heterogeneous (26Al/27Al)0, where the source reservoirs of most primitive meteorite components have lower (26Al/27Al)0 at ~2.7 × 10-5 and Δ'26Mg0 of -16 ppm. We measured the magnesium isotope compositions of primitive meteoritic olivine, which originated outside of the CAI-forming reservoir(s), and report five grains whose Δ'26Mg0 are within uncertainty of -35 ppm. Our data thus affirm a model of a largely homogeneous protoplanetary disc with (26Al/27Al)0 of ~5 × 10-5, supporting the accuracy of the 26Al→26Mg chronometer.
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Affiliation(s)
- Timothy Gregory
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Bristol BS8 1RJ, UK
- Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
- National Environmental Isotope Facility, British Geological Survey, Nottingham NG12 5GG, UK
| | - Tu-Han Luu
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Bristol BS8 1RJ, UK
| | - Christopher D. Coath
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Bristol BS8 1RJ, UK
| | - Sara S. Russell
- Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
| | - Tim Elliott
- School of Earth Sciences, University of Bristol, Wills Memorial Building, Bristol BS8 1RJ, UK
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Han J, Keller LP, Liu MC, Needham AW, Hertwig AT, Messenger S, Simon JI. A Coordinated Microstructural and Isotopic Study of a Wark-Lovering Rim on a Vigarano CAI. GEOCHIMICA ET COSMOCHIMICA ACTA 2020; 269:639-660. [PMID: 32020947 PMCID: PMC6999757 DOI: 10.1016/j.gca.2019.10.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We carried out a coordinated mineralogical and isotopic study of a Wark-Lovering (WL) rim on a Ca,Al-rich inclusion (CAI) from the reduced CV3 chondrite Vigarano. The outermost edge of the CAI mantle is mineralogically and texturally distinct compared to the underlying mantle that is composed of coarse, zoned melilite (Åk~10-60) grains. The mantle edge contains fine-grained gehlenite with hibonite and rare grossite that likely formed by rapid crystallization from a melt enriched in Ca and Al. These gehlenite and hibonite layers are surrounded by successive layers of spinel, zoned melilite (Åk~0-10), zoned diopside that grades outwards from Al,Ti-rich to Al,Ti-poor, and forsteritic olivine intergrown with diopside. These layered textures are indicative of sequential condensation of spinel, melilite, diopside, and forsterite onto hibonite. Anorthite occurs as a discontinuous layer that corrodes adjacent melilite and Al-diopside, and appears to have replaced them, probably even later than the forsterite layer formation. Based on these observations, we conclude that the WL rim formation was initiated by flash melting and extensive evaporation of the original inclusion edge, followed by subsequent gas-solid reactions under highly dynamic conditions. All the WL rim minerals are 16O-rich (Δ17O = ~-23‰), indicating their formation in an 16O-rich nebular reservoir. Our Al-Mg measurements of hibonite, spinel, and diopside from the WL rim, as well as spinel and Al,Ti-diopside in the core, define a single, well-correlated isochron with an inferred initial 26Al/27Al ratio of (4.94 ± 0.12) × 10-5. This indicates that the WL rim formed shortly after the host CAI. In contrast, the lack of 26Mg excesses in the WL rim anorthite suggest its later formation or later isotopic disturbance in the solar nebula, after 26Al had decayed.
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Affiliation(s)
- Jangmi Han
- Lunar and Planetary Institute, USRA, 3600 Bay Area Boulevard, Houston, TX 77058, USA
- Astromaterials Research and Exploration Science, NASA Johnson Space Center, Houston, TX 77058, USA
| | - Lindsay P. Keller
- Astromaterials Research and Exploration Science, NASA Johnson Space Center, Houston, TX 77058, USA
| | - Ming-Chang Liu
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Andrew W. Needham
- Lunar and Planetary Institute, USRA, 3600 Bay Area Boulevard, Houston, TX 77058, USA
- Astromaterials Research and Exploration Science, NASA Johnson Space Center, Houston, TX 77058, USA
| | - Andreas T. Hertwig
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Scott Messenger
- Astromaterials Research and Exploration Science, NASA Johnson Space Center, Houston, TX 77058, USA
| | - Justin I. Simon
- Astromaterials Research and Exploration Science, NASA Johnson Space Center, Houston, TX 77058, USA
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Hertwig AT, Kimura M, Defouilloy C, Kita NT. Oxygen isotope systematics of chondrule olivine, pyroxene, and plagioclase in one of the most pristine CV3 Red chondrites (Northwest Africa 8613). METEORITICS & PLANETARY SCIENCE 2019; 54:2666-2685. [PMID: 32256025 PMCID: PMC7121232 DOI: 10.1111/maps.13379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Accepted: 07/22/2019] [Indexed: 06/11/2023]
Abstract
We performed in situ oxygen three-isotope measurements of chondrule olivine, pyroxenes, and plagioclase from the newly described CVRed chondrite NWA 8613. Additionally, oxygen isotope ratios of plagioclase in chondrules from the Kaba CV3OxB chondrite were determined to enable comparisons of isotope ratios and degree of alteration of chondrules in both CV lithologies. NWA 8613 was affected by only mild thermal metamorphism. The majority of oxygen isotope ratios of olivine and pyroxenes plot along a slope-1 line in the oxygen three-isotope diagram, except for a type II and a remolten barred olivine chondrule. When isotopic relict olivine is excluded, olivine, low- and high-Ca pyroxenes are indistinguishable regarding Δ17O values. Conversely, plagioclase in chondrules from NWA 8613 and Kaba plot along mass-dependent fractionation lines. Oxygen isotopic disequilibrium between phenocrysts and plagioclase was caused probably by exchange of plagioclase with 16O-poor fluids on the CV parent body. Based on an existing oxygen isotope mass balance model, possible dust enrichment and ice enhancement factors were estimated. Type I chondrules from NWA 8613 possibly formed at moderately high dust enrichment factors (50× to 150× CI dust relative to Solar abundances); estimates for water ice in the chondrule precursors range from 0.2 to 0.6× the nominal amount of ice in dust of CI composition. Findings agree with results from an earlier study on oxygen isotopes in chondrules of the Kaba CV chondrite, providing further evidence for a relatively dry and only moderately high dust-enriched disk in the CV chondrule-forming region.
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Affiliation(s)
- Andreas T. Hertwig
- WiscSIMS, Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, USA
- Present address: Department of Earth, Planetary, and Space Sciences, University of California-Los Angeles, Los Angeles, CA 90095, USA
| | - Makoto Kimura
- National Institute of Polar Research, Meteorite Research Center, Midoricho 10-3, Tachikawa, Tokyo 190-8518, Japan
| | - Céline Defouilloy
- WiscSIMS, Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Noriko T. Kita
- WiscSIMS, Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, USA
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Villeneuve J, Chaussidon M, Marrocchi Y, Deng Z, Watson EB. High-precision in situ silicon isotopic analyses by multi-collector secondary ion mass spectrometry in olivine and low-calcium pyroxene. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2019; 33:1589-1597. [PMID: 31237970 DOI: 10.1002/rcm.8508] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 06/16/2019] [Accepted: 06/17/2019] [Indexed: 06/09/2023]
Affiliation(s)
- Johan Villeneuve
- Centre de Recherches Pétrographiques et Géochimiques, CNRS UMR 7358, Université de Lorraine, 15 rue Notre-Dame des Pauvres, Vandœuvre-lès-Nancy, 54501, France
| | - Marc Chaussidon
- Institut de Physique du Globe de Paris, Université Sorbonne Paris Cité, CNRS UMR 7154, 1 rue Jussieu, 75238, Paris, France
| | - Yves Marrocchi
- Centre de Recherches Pétrographiques et Géochimiques, CNRS UMR 7358, Université de Lorraine, 15 rue Notre-Dame des Pauvres, Vandœuvre-lès-Nancy, 54501, France
| | - Zhengbin Deng
- Institut de Physique du Globe de Paris, Université Sorbonne Paris Cité, CNRS UMR 7154, 1 rue Jussieu, 75238, Paris, France
| | - E Bruce Watson
- Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
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Tenner TJ, Nakashima D, Ushikubo T, Tomioka N, Kimura M, Weisberg MK, Kita NT. Extended chondrule formation intervals in distinct physicochemical environments: Evidence from Al-Mg isotope systematics of CR chondrite chondrules with unaltered plagioclase. GEOCHIMICA ET COSMOCHIMICA ACTA 2019; 260:133-160. [PMID: 32255837 PMCID: PMC7121246 DOI: 10.1016/j.gca.2019.06.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Al-Mg isotope systematics of twelve FeO-poor (type I) chondrules from CR chondrites Queen Alexandra Range 99177 and Meteorite Hills 00426 were investigated by secondary ion mass spectrometry (SIMS). Five chondrules with Mg#'s of 99.0 to 99.2 and Δ17O of -4.2‰ to -5.3‰ have resolvable excess 26Mg. Their inferred (26Al/27Al)0 values range from (3.5 ± 1.3) × 10‒6 to (6.0 ± 3.9) × 10‒6. This corresponds to formation times of 2.2 (-0.5/+1.1) Myr to 2.8 (‒0.3/+0.5) Myr after CAIs, using a canonical (26Al/27Al)0 of 5.23 × 10-5, and assuming homogeneously distributed 26Al that yielded a uniform initial 26Al/27Al in the Solar System. Seven chondrules lack resolvable excess 26Mg. They have lower Mg#'s (94.2 to 98.7) and generally higher Δ17O (-0.9‰ to -4.9‰) than chondrules with resolvable excess 26Mg. Their inferred (26Al/27Al)0 upper limits range from 1.3 × 10‒6 to 3.2 × 10‒6, corresponding to formation >2.9 to >3.7 Myr after CAIs. Al-Mg isochrons depend critically on chondrule plagioclase, and several characteristics indicate the chondrule plagioclase is unaltered: (1) SIMS 27Al/24Mg depth profile patterns match those from anorthite standards, and SEM/EDS of chondrule SIMS pits show no foreign inclusions; (2) transmission electron microscopy (TEM) reveals no nanometer-scale micro-inclusions and no alteration due to thermal metamorphism; (3) oxygen isotopes of chondrule plagioclase match those of coexisting olivine and pyroxene, indicating a low extent of thermal metamorphism; and (4) electron microprobe data show chondrule plagioclase is anorthite-rich, with excess structural silica and high MgO, consistent with such plagioclase from other petrologic type 3.00-3.05 chondrites. We conclude that the resolvable (26Al/27Al)0 variabilities among chondrules studied are robust, corresponding to a formation interval of at least 1.1 Myr. Using relationships between chondrule (26Al/27Al)0, Mg#, and Δ17O, we interpret spatial and temporal features of dust, gas, and H2O ice in the FeO-poor chondrule-forming environment. Mg# ≥ 99, Δ17O ~-5‰ chondrules with resolvable excess 26Mg initially formed in an environment that was relatively anhydrous, with a dust-to-gas ratio of ~100×. After these chondrules formed, we interpret a later influx of 16O-poor H2O ice into the environment, and that dust-to-gas ratios expanded (100× to 300×). This led to the later formation of more oxidized Mg# 94-99 chondrules with higher Δ17O (-5‰ to -1‰), with low (26Al/27Al)0, and hence no resolvable excess 26Mg. We refine the mean CR chondrite chondrule formation age via mass balance, by considering that Mg# ≥ 99 chondrules generally have resolved positive (26Al/27Al)0 and that Mg# < 99 chondrules generally have no resolvable excess 26Mg, implying lower (26Al/27Al)0. We obtain a mean chondrule formation age of 3.8 ± 0.3 Myr after CAIs, which is consistent with Pb-Pb and Hf-W model ages of CR chondrite chondrule aggregates. Overall, this suggests most CR chondrite chondrules formed immediately before parent body accretion.
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Affiliation(s)
- Travis J Tenner
- WiscSIMS, Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, USA
- Chemistry Division, Nuclear and Radiochemistry, Los Alamos National Laboratory, MSJ514, Los Alamos, NM 87545, USA
| | - Daisuke Nakashima
- WiscSIMS, Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Earth and Planetary Material Sciences, Faculty of Science, Tohoku University, Aoba, Sendai, Miyagi 980-8578, Japan
| | - Takayuki Ushikubo
- WiscSIMS, Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, USA
- Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 200 Monobe Otsu, Nankoku, Kochi 783-8502, Japan
| | - Naotaka Tomioka
- Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 200 Monobe Otsu, Nankoku, Kochi 783-8502, Japan
| | - Makoto Kimura
- Faculty of Science, Ibaraki University, Mito 310-8512, Japan
- National Institute of Polar Research, Tokyo 190-8518, Japan
| | - Michael K Weisberg
- Kingsborough Community College and Graduate Center, The City University of New York, 2001 Oriental Boulevard, Brooklyn, NY 11235-2398, USA
- American Museum of Natural History, Central Park West at 79 Street, New York, NY, 10024-5192, USA
| | - Noriko T Kita
- WiscSIMS, Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, USA
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Hertwig AT, Makoto K, Ushikubo T, Defouilloy C, Kita NT. The 26Al- 26Mg systematics of FeO-rich chondrules from Acfer 094: two chondrule generations distinct in age and oxygen isotope ratios. GEOCHIMICA ET COSMOCHIMICA ACTA 2019; 253:111-126. [PMID: 32214432 PMCID: PMC7094794 DOI: 10.1016/j.gca.2019.02.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The 26Al-26Mg ages of FeO-rich (type II) chondrules from Acfer 094, one of the least thermally metamorphosed carbonaceous chondrites, were determined by SIMS analysis of plagioclase and olivine/pyroxene using a radio frequency (RF) plasma oxygen ion source. In combination with preexisting 26Al-26Mg ages of FeO-poor (type I) chondrules, the maximum range of formation ages recorded in chondrules from a single meteorite is determined to help provide constraints on models of material transport in the proto-planetary disk. We also report new SIMS oxygen three-isotope analyses of type II chondrules in Acfer 094. All but one of the plagioclase analyses show resolvable excesses in 26Mg and isochron regressions yield initial 26Al/27Al ratios of type II chondrules that range from (3.62 ± 0.86) × 10-6 to (9.3 ± 1.1) × 10-6, which translates to formation ages between 2.71 -0.22/+0.28 Ma and 1.75 -0.11/+0.12 Ma after CAI. This overall range is indistinguishable from that determined for type I chondrules in Acfer 094. The initial 26Al/27Al ratio of the oldest type II chondrule is resolved from that of all other type II chondrules in Acfer 094. Importantly, the oldest type I chondrule and the oldest type II chondrule in Acfer 094 possess within analytical error indistinguishable initial 26Al/27Al ratios and Δ17O values of ~0‰. Ages and oxygen isotope ratios clearly set these two chondrules apart from all other chondrules in Acfer 094. It is therefore conceivable that the formation region of these two chondrules differs from that of other chondrules and in turn suggests that Acfer 094 contains two distinct chondrule generations.
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Affiliation(s)
- Andreas T Hertwig
- WiscSIMS, Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Kimura Makoto
- National Institute of Polar Research, Meteorite Research Center, Midoricho 10-3, Tachikawa, Tokyo 190-8518, Japan
| | - Takayuki Ushikubo
- Kochi Institute for Core Sample Research, JAMSTEC, 200 Monobe-otsu, Nankoku, Kochi 783-8502 Japan
| | - Céline Defouilloy
- WiscSIMS, Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Noriko T Kita
- WiscSIMS, Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, USA
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12
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The Effect of Jupiter's Formation on the Distribution of Refractory Elements and Inclusions in Meteorites. ACTA ACUST UNITED AC 2018. [DOI: 10.3847/1538-4365/aad95f] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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13
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Libourel G, Portail M. Chondrules as direct thermochemical sensors of solar protoplanetary disk gas. SCIENCE ADVANCES 2018; 4:eaar3321. [PMID: 30009256 PMCID: PMC6040862 DOI: 10.1126/sciadv.aar3321] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 05/30/2018] [Indexed: 05/31/2023]
Abstract
Chondrules, millimeter-sized igneous spherules comprising the major component of most chondritic meteorites, formed during the first 4 million to 5 million years of the evolution of the solar protoplanetary disk and, therefore, can potentially offer important constraints on the conditions in the disk, provided that the processes that led to their formation can be understood. High-resolution cathodoluminescence (CL) survey of chondrules from various chondrite groups revealed changes of CL activator concentrations of magnesium-rich olivines. We show that these overlooked internal zoning structures provide evidence for high-temperature gas-assisted near-equilibrium epitaxial growth of olivines during chondrule formation. We argue that this interaction with the surrounding gas, rather than various cooling histories, defined chondrule composition and texture. Chondrules are thus direct thermochemical sensors of their high-temperature gaseous environment, and high partial pressures of gaseous Mg and SiO are required in their solar protoplanetary disk-forming region to maintain olivine saturation in chondrules. The inferred crystallization of olivines, from stable melts approaching equilibrium with the surrounding gas, provides an explanation for the notable absence of large and systematic isotopic fractionations in chondrules.
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Affiliation(s)
- Guy Libourel
- Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, UMR 7293 Lagrange, Boulevard de l’Observatoire, CS34229, 06304 Nice Cedex 4, France
- Hawai‘i Institute of Geophysics and Planetology, School of Ocean, Earth Science and Technology, University of Hawai‘i, Mānoa, Honolulu, HI 96821, USA
| | - Marc Portail
- Université Côte d’Azur, CNRS–Centre de Recherches sur l’Hétéro-Epitaxie et ses Applications), Sophia Antipolis, Rue Bernard Grégory, 06560 Valbonne, France
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14
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O'D Alexander CM, McKeegan KD, Altwegg K. Water Reservoirs in Small Planetary Bodies: Meteorites, Asteroids, and Comets. SPACE SCIENCE REVIEWS 2018; 214:36. [PMID: 30842688 PMCID: PMC6398961 DOI: 10.1007/s11214-018-0474-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 01/11/2018] [Indexed: 06/09/2023]
Abstract
Asteroids and comets are the remnants of the swarm of planetesimals from which the planets ultimately formed, and they retain records of processes that operated prior to and during planet formation. They are also likely the sources of most of the water and other volatiles accreted by Earth. In this review, we discuss the nature and probable origins of asteroids and comets based on data from remote observations, in situ measurements by spacecraft, and laboratory analyses of meteorites derived from asteroids. The asteroidal parent bodies of meteorites formed ≤4 Ma after Solar System formation while there was still a gas disk present. It seems increasingly likely that the parent bodies of meteorites spectroscopically linked with the E-, S-, M- and V-type asteroids formed sunward of Jupiter's orbit, while those associated with C- and, possibly, D-type asteroids formed further out, beyond Jupiter but probably not beyond Saturn's orbit. Comets formed further from the Sun than any of the meteorite parent bodies, and retain much higher abundances of interstellar material. CI and CM group meteorites are probably related to the most common C-type asteroids, and based on isotopic evidence they, rather than comets, are the most likely sources of the H and N accreted by the terrestrial planets. However, comets may have been major sources of the noble gases accreted by Earth and Venus. Possible constraints that these observations can place on models of giant planet formation and migration are explored.
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Affiliation(s)
- Conel M O'D Alexander
- Dept. Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Road NW, Washington, DC 20015, USA. . Tel. (202) 478 8478
| | - Kevin D McKeegan
- Department of Earth, Planetary, and Space Sciences, University of California-Los Angeles, Los Angeles, CA 90095-1567, USA.
| | - Kathrin Altwegg
- Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland.
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15
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Bollard J, Connelly JN, Whitehouse MJ, Pringle EA, Bonal L, Jørgensen JK, Nordlund Å, Moynier F, Bizzarro M. Early formation of planetary building blocks inferred from Pb isotopic ages of chondrules. SCIENCE ADVANCES 2017; 3:e1700407. [PMID: 28808680 PMCID: PMC5550225 DOI: 10.1126/sciadv.1700407] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 07/11/2017] [Indexed: 06/01/2023]
Abstract
The most abundant components of primitive meteorites (chondrites) are millimeter-sized glassy spherical chondrules formed by transient melting events in the solar protoplanetary disk. Using Pb-Pb dates of 22 individual chondrules, we show that primary production of chondrules in the early solar system was restricted to the first million years after the formation of the Sun and that these existing chondrules were recycled for the remaining lifetime of the protoplanetary disk. This finding is consistent with a primary chondrule formation episode during the early high-mass accretion phase of the protoplanetary disk that transitions into a longer period of chondrule reworking. An abundance of chondrules at early times provides the precursor material required to drive the efficient and rapid formation of planetary objects via chondrule accretion.
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Affiliation(s)
- Jean Bollard
- Centre for Star and Planet Formation, University of Copenhagen, Copenhagen, Denmark
| | - James N. Connelly
- Centre for Star and Planet Formation, University of Copenhagen, Copenhagen, Denmark
| | | | - Emily A. Pringle
- Institut de Physique du Globe de Paris, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Lydie Bonal
- Institut de Planétologie et d’Astrophysique de Grenoble, Grenoble, France
| | - Jes K. Jørgensen
- Centre for Star and Planet Formation, University of Copenhagen, Copenhagen, Denmark
| | - Åke Nordlund
- Centre for Star and Planet Formation, University of Copenhagen, Copenhagen, Denmark
| | - Frédéric Moynier
- Institut de Physique du Globe de Paris, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Martin Bizzarro
- Centre for Star and Planet Formation, University of Copenhagen, Copenhagen, Denmark
- Institut de Physique du Globe de Paris, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
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16
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Olsen MB, Wielandt D, Schiller M, Van Kooten EM, Bizzarro M. Magnesium and 54Cr isotope compositions of carbonaceous chondrite chondrules - Insights into early disk processes. GEOCHIMICA ET COSMOCHIMICA ACTA 2016; 191:118-138. [PMID: 27563152 PMCID: PMC4993235 DOI: 10.1016/j.gca.2016.07.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We report on the petrology, magnesium isotopes and mass-independent 54Cr/52Cr compositions (μ54Cr) of 42 chondrules from CV (Vigarano and NWA 3118) and CR (NWA 6043, NWA 801 and LAP 02342) chondrites. All sampled chondrules are classified as type IA or type IAB, have low 27Al/24Mg ratios (0.04-0.27) and display little or no evidence for secondary alteration processes. The CV and CR chondrules show variable 25Mg/24Mg and 26Mg/24Mg values corresponding to a range of mass-dependent fractionation of ~500 ppm (parts per million) per atomic mass unit. This mass-dependent Mg isotope fractionation is interpreted as reflecting Mg isotope heterogeneity of the chondrule precursors and not the result of secondary alteration or volatility-controlled processes during chondrule formation. The CV and CR chondrule populations studied here are characterized by systematic deficits in the mass-independent component of 26Mg (μ26Mg*) relative to the solar value defined by CI chondrites, which we interpret as reflecting formation from precursor material with a reduced initial abundance of 26Al compared to the canonical 26Al/27Al of ~5 × 10-5. Model initial 26Al/27Al values of CV and CR chondrules vary from (1.5 ± 4.0) × 10-6 to (2.2 ± 0.4) × 10-5. The CV chondrules display significant μ54Cr variability, defining a range of compositions that is comparable to that observed for inner Solar System primitive and differentiated meteorites. In contrast, CR chondrites are characterized by a narrower range of μ54Cr values restricted to compositions typically observed for bulk carbonaceous chondrites. Collectively, these observations suggest that the CV chondrules formed from precursors that originated in various regions of the protoplanetary disk and were then transported to the accretion region of the CV parent asteroid whereas CR chondrule predominantly formed from precursor with carbonaceous chondrite-like μ54Cr signatures. The observed μ54Cr variability in chondrules from CV and CR chondrites suggest that the matrix and chondrules did not necessarily formed from the same reservoir. The coupled μ26Mg* and μ54Cr systematics of CR chondrules establishes that these objects formed from a thermally unprocessed and 26Al-poor source reservoir distinct from most inner Solar System asteroids and planetary bodies, possibly located beyond the orbits of the gas giants. In contrast, a large fraction of the CV chondrules plot on the inner Solar System correlation line, indicating that these objects predominantly formed from thermally-processed, 26Al-bearing precursor material akin to that of inner Solar System solids, asteroids and planets.
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Affiliation(s)
- Mia B. Olsen
- Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, DK-1350, Denmark
| | - Daniel Wielandt
- Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, DK-1350, Denmark
| | - Martin Schiller
- Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, DK-1350, Denmark
| | - Elishevah M.M.E. Van Kooten
- Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, DK-1350, Denmark
| | - Martin Bizzarro
- Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, DK-1350, Denmark
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18
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Morris MA, Garvie LAJ, Knauth LP. NEW INSIGHT INTO THE SOLAR SYSTEM'S TRANSITION DISK PHASE PROVIDED BY THE METAL-RICH CARBONACEOUS CHONDRITE ISHEYEVO. THE ASTROPHYSICAL JOURNAL. LETTERS 2015; 801:L22. [PMID: 30705746 PMCID: PMC6350786 DOI: 10.1088/2041-8205/801/2/l22] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Many aspects of planet formation are controlled by the amount of gas remaining in the natal protoplanetary disks (PPDs). Infrared observations show that PPDs undergo a transition stage at several megayears, during which gas densities are reduced. Our Solar System would have experienced such a stage. However, there is currently no data that provides insight into this crucial time in our PPD's evolution. We show that the Isheyevo meteorite contains the first definitive evidence for a transition disk stage in our Solar System. Isheyevo belongs to a class of metal-rich meteorites whose components have been dated at almost 5 Myr after formation of Ca, Al-rich inclusions, and exhibits unique sedimentary layers that imply formation through gentle sedimentation. We show that such layering can occur via the gentle sweep-up of material found in the impact plume resulting from the collision of two planetesimals. Such sweep-up requires gas densities consistent with observed transition disks (10-12-10-11 g cm-3). As such, Isheyevo presents the first evidence of our own transition disk and provides new constraints on the evolution of our solar nebula.
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Affiliation(s)
- Melissa A Morris
- State University of New York, Cortland, NY 13045, USA;
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, USA
| | - Laurence A J Garvie
- Center for Meteorite Studies, Arizona State University, Tempe, AZ 85287, USA
| | - L Paul Knauth
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, USA
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19
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Short time interval for condensation of high-temperature silicates in the solar accretion disk. Proc Natl Acad Sci U S A 2015; 112:1298-303. [PMID: 25605942 DOI: 10.1073/pnas.1414025112] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chondritic meteorites are made of primitive components that record the first steps of formation of solids in our Solar System. Chondrules are the major component of chondrites, yet little is known about their formation mechanisms and history within the solar protoplanetary disk (SPD). We use the reconstructed concentrations of short-lived (26)Al in chondrules to constrain the timing of formation of their precursors in the SPD. High-precision bulk magnesium isotopic measurements of 14 chondrules from the Allende chondrite define a (26)Al isochron with (26)Al/(27)Al = 1.2(±0.2) × 10(-5) for this subset of Allende chondrules. This can be considered to be the minimum bulk chondrule (26)Al isochron because all chondrules analyzed so far with high precision (∼50 chondrules from CV and ordinary chondrites) have an inferred minimum bulk initial ((26)Al/(27)Al) ≥ 1.2 × 10(-5). In addition, mineral (26)Al isochrons determined on the same chondrules show that their formation (i.e., fusion of their precursors by energetic events) took place from 0 Myr to ∼2 Myr after the formation of their precursors, thus showing in some cases a clear decoupling in time between the two events. The finding of a minimum bulk chondrule (26)Al isochron is used to constrain the astrophysical settings for chondrule formation. Either the temperature of the condensation zone dropped below the condensation temperature of chondrule precursors at ∼1.5 My after the start of the Solar System or the transport of precursors from the condensation zone to potential storage sites stopped after 1.5 My, possibly due to a drop in the disk accretion rate.
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20
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Pressure-temperature evolution of primordial solar system solids during impact-induced compaction. Nat Commun 2014; 5:5451. [PMID: 25465283 PMCID: PMC4268713 DOI: 10.1038/ncomms6451] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 10/02/2014] [Indexed: 11/08/2022] Open
Abstract
Prior to becoming chondritic meteorites, primordial solids were a poorly consolidated mix of mm-scale igneous inclusions (chondrules) and high-porosity sub-μm dust (matrix). We used high-resolution numerical simulations to track the effect of impact-induced compaction on these materials. Here we show that impact velocities as low as 1.5 km s(-1) were capable of heating the matrix to >1,000 K, with pressure-temperature varying by >10 GPa and >1,000 K over ~100 μm. Chondrules were unaffected, acting as heat-sinks: matrix temperature excursions were brief. As impact-induced compaction was a primary and ubiquitous process, our new understanding of its effects requires that key aspects of the chondrite record be re-evaluated: palaeomagnetism, petrography and variability in shock level across meteorite groups. Our data suggest a lithification mechanism for meteorites, and provide a 'speed limit' constraint on major compressive impacts that is inconsistent with recent models of solar system orbital architecture that require an early, rapid phase of main-belt collisional evolution.
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21
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Tatischeff V, Duprat J, de Séréville N. LIGHT-ELEMENT NUCLEOSYNTHESIS IN A MOLECULAR CLOUD INTERACTING WITH A SUPERNOVA REMNANT AND THE ORIGIN OF BERYLLIUM-10 IN THE PROTOSOLAR NEBULA. ACTA ACUST UNITED AC 2014. [DOI: 10.1088/0004-637x/796/2/124] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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22
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Morbidelli A. Scenarios of giant planet formation and evolution and their impact on the formation of habitable terrestrial planets. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2014; 372:20130072. [PMID: 24664911 DOI: 10.1098/rsta.2013.0072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In our Solar System, there is a clear divide between the terrestrial and giant planets. These two categories of planets formed and evolved separately, almost in isolation from each other. This was possible because Jupiter avoided migrating into the inner Solar System, most probably due to the presence of Saturn, and never acquired a large-eccentricity orbit, even during the phase of orbital instability that the giant planets most likely experienced. Thus, the Earth formed on a time scale of several tens of millions of years, by collision of Moon- to Mars-mass planetary embryos, in a gas-free and volatile-depleted environment. We do not expect, however, that this clear cleavage between the giant and terrestrial planets is generic. In many extrasolar planetary systems discovered to date, the giant planets migrated into the vicinity of the parent star and/or acquired eccentric orbits. In this way, the evolution and destiny of the giant and terrestrial planets become intimately linked. This paper discusses several evolutionary patterns for the giant planets, with an emphasis on the consequences for the formation and survival of habitable terrestrial planets. The conclusion is that we should not expect Earth-like planets to be typical in terms of physical and orbital properties and accretion history. Most habitable worlds are probably different, exotic worlds.
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Affiliation(s)
- Alessandro Morbidelli
- Laboratoire Lagrange, CNRS, Observatoire de la Côte d'Azur, Université de Nice - Sophia Antipolis, , BP 4229, 06304 Nice Cedex 4, France
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23
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Depalo R, Caciolli A, Marchi T, Appannababu S, Blasi N, Broggini C, Camera F, Cinausero M, Collanzuol G, Fabris D, Gramegna F, Kravchuk VL, Leone M, Lombardi A, Mastinu P, Menegazzo R, Montagnoli G, Prete G, Rigato V, Rossi Alvarez C, Wieland O. Measurement of the 25Mg( α,n) 28Si reaction cross section at LNL. EPJ WEB OF CONFERENCES 2014. [DOI: 10.1051/epjconf/20146607002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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24
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Abstract
Recent developments in analytical instrumentation have led to revolutionary discoveries in cosmochemistry. Instrumental advances have been made along two lines: (i) increase in spatial resolution and sensitivity of detection, allowing for the study of increasingly smaller samples, and (ii) increase in the precision of isotopic analysis that allows more precise dating, the study of isotopic heterogeneity in the Solar System, and other studies. A variety of instrumental techniques are discussed, and important examples of discoveries are listed. Instrumental techniques and instruments include the ion microprobe, laser ablation gas MS, Auger EM, resonance ionization MS, accelerator MS, transmission EM, focused ion-beam microscopy, atom probe tomography, X-ray absorption near-edge structure/electron loss near-edge spectroscopy, Raman microprobe, NMR spectroscopy, and inductively coupled plasma MS.
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25
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Affiliation(s)
- Larry R Nittler
- Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road, NW, Washington, DC 20015, USA.
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26
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Matzel JEP, Ishii HA, Joswiak D, Hutcheon ID, Bradley JP, Brownlee D, Weber PK, Teslich N, Matrajt G, McKeegan KD, MacPherson GJ. Constraints on the formation age of cometary material from the NASA Stardust mission. Science 2010; 328:483-6. [PMID: 20185683 DOI: 10.1126/science.1184741] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We measured the 26Al-26Mg isotope systematics of a approximately 5-micrometer refractory particle, Coki, returned from comet 81P/Wild 2 in order to relate the time scales of formation of cometary inclusions to their meteoritic counterparts. The data show no evidence of radiogenic 26Mg and define an upper limit to the abundance of 26Al at the time of particle formation: 26Al/27Al < 1 x 10(-5). The absence of 26Al indicates that Coki formed >1.7 million years after the oldest solids in the solar system, calcium- and aluminum-rich inclusions (CAIs). The data suggest that high-temperature inner solar system material formed, was subsequently transferred to the Kuiper Belt, and was incorporated into comets several million years after CAI formation.
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Affiliation(s)
- J E P Matzel
- Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
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Affiliation(s)
- Andrew M. Davis
- Department of the Geophysical Sciences, Enrico Fermi Institute and Chicago Center for Cosmochemistry, University of Chicago, Chicago, IL 60637, USA
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