Compositional continuity of enstatite chondrites and implications for heterogeneous accretion of the enstatite chondrite parent body

AbstractIgneous graphite, a rare constituent in terrestrial mafic and ultramafic rocks, occurs in three EH and one EL enstatite chondrite impact-melt breccias as 2–150 µm long euhedral laths, some with pyramidal terminations. In contrast, graphite in most enstatite chondrites exsolved from metallic Fe-Ni as polygonal, rounded or irregular aggregates. Literature data for five EH chondrites on C combusting at high temperatures show that Abee contains the most homogeneous C isotopes (i.e. δ13C = −8.1 ± 2.1‰); in addition, Abee's mean δ13C value is the same as the average high-temperature C value for the set of five EH chondrites. This suggests that Abee scavenged C from a plurality of sources on its parent body and homogenized the C during a large-scale melting event. Whereas igneous graphite in terrestrial rocks typically forms at relatively high pressure and only moderately low oxygen fugacity (e.g., ∼ 5 kbar, logfO2 ∼ −10 at 1200°C), igneous graphite in asteroidal meteorites formed at much lower pressures and oxygen fugacities.

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Cathodoluminescence color zonation in the Antarctic meteorite (enstatite chondrite) of Yamato 86004

Geochronometria ◽

10.1515/geochr-2015-0053 ◽

2017 ◽

Vol 44 (1) ◽

pp. 136-141

Author(s):

Syuhei Ohgo ◽

Maki Mishima ◽

Minoru Endo ◽

Kiyotaka Ninagawa ◽

Hirotsugu Nishido

Keyword(s):

Parent Body ◽

Structural Defects ◽

Light Blue ◽

Blue Region ◽

Defect Centers ◽

Broad Emission ◽

Concentric Pattern ◽

Enstatite Chondrite ◽

Impurity Centers ◽

The Antarctic

Abstract Enstatite in Yamato 86004 classified as EH melt rock shows cathodoluminescence (CL) zonation as arranged in a concentric pattern from within outward blue, light blue, red and non-CL areas (fusion crust). The zonation observed in the meteorite results from different distribution ratio of the enstatite with various CL colors. CL spectra of the enstatite have two broad emission bands at around 400 nm in the blue region and at around 670 nm in a red region. The emission components obtained by a spectral deconvolution can be assigned to three defect centers (2.73, 3.13–3.15 and 3.77 eV) in a blue region and to impurity centers of Cr3+ ion (1.71 eV) and Mn2+ ion (1.86–1.91 eV) in a red region. According to the CL related to structural defects in the enstatite, blue-CL enstatite might be originally formed from the melt by a quenching from the melt on the surface of parent body. The enstatite with light blue and red CL might be thermally altered from blue-CL enstatite with phase transitions during a flash heating when the meteorite passed through the atmosphere. Therefore, the color CL zonation reflects a thermal history recorded in the meteorite.

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Enstatite chondrites and enstatite achondrites (aubrites) were not derived from the same parent body

Earth and Planetary Science Letters ◽

10.1016/0012-821x(86)90095-6 ◽

1986 ◽

Vol 81 (1) ◽

pp. 1-6 ◽

Cited By ~ 24

Author(s):

Robin Brett ◽

Klaus Keil

Keyword(s):

Parent Body ◽

Enstatite Chondrites ◽

Enstatite Achondrites

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Chromium Stable Isotope Panorama of Chondrites and Implications for Earth Early Accretion

The Astrophysical Journal ◽

10.3847/1538-4357/ac2570 ◽

2021 ◽

Vol 923 (1) ◽

pp. 94

Author(s):

Ke Zhu ◽

Frédéric Moynier ◽

Conel M. O’D. Alexander ◽

Jemma Davidson ◽

Devin L. Schrader ◽

...

Keyword(s):

Stable Isotope ◽

Isotopic Composition ◽

Isotope Composition ◽

Acid Leaching ◽

Building Blocks ◽

Silicon Isotope ◽

Stable Isotope Fractionation ◽

Two Samples ◽

Enstatite Chondrite ◽

Enstatite Chondrites

Abstract We investigated the stable isotope fractionation of chromium (Cr) for a panorama of chondrites, including EH and EL enstatite chondrites and their chondrules and different phases (by acid leaching). We observed that chondrites have heterogeneous δ 53Cr values (per mil deviation of the 53Cr/52Cr from the NIST SRM 979 standard), which we suggest reflect different physical conditions in the different chondrite accretion regions. Chondrules from a primitive EH3 chondrite (SAH 97096) possess isotopically heavier Cr relative to their host bulk chondrite, which may be caused by Cr evaporation in a reduced chondrule-forming region of the protoplanetary disk. Enstatite chondrites show a range of bulk δ 53Cr values that likely result from variable mixing of isotopically different sulfide-silicate-metal phases. The bulk silicate Earth (δ 53Cr = –0.12 ± 0.02‰, 2SE) has a lighter Cr stable isotope composition compared to the average δ 53Cr value of enstatite chondrites (–0.05 ± 0.02‰, 2SE, when two samples out of 19 are excluded). If the bulk Earth originally had a Cr isotopic composition that was similar to the average enstatite chondrites, this Cr isotope difference may be caused by evaporation under equilibrium conditions from magma oceans on Earth or its planetesimal building blocks, as previously suggested to explain the magnesium and silicon isotope differences between Earth and enstatite chondrites. Alternatively, chemical differences between Earth and enstatite chondrite can result from thermal processes in the solar nebula and the enstatite chondrite-Earth, which would also have changed the Cr isotopic composition of Earth and enstatite chondrite parent body precursors.

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High-temperature mass spectrometric degassing of enstatite chondrites: Implications for pyroclastic volcanism on the aubrite parent body

Geochimica et Cosmochimica Acta ◽

10.1016/0016-7037(92)90267-m ◽

1992 ◽

Vol 56 (12) ◽

pp. 4267-4280 ◽

Cited By ~ 35

Author(s):

David W Muenow ◽

klaus Keil ◽

Lionel Wilson

Keyword(s):

High Temperature ◽

Parent Body ◽

Mass Spectrometric ◽

Enstatite Chondrites

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Increasing Energy Ration of Bali Cattle to Improve Digestible Nutrient, Milk Yield and Milk Quality

International Research Journal of Engineering IT & Scientific Research ◽

10.21744/irjeis.v3i1.359 ◽

2017 ◽

Vol 3 (1) ◽

pp. 7

Author(s):

Ni Nyoman Suryani ◽

I Wayan Suarna ◽

Ni Putu Sarini ◽

I Gede Mahardika

Keyword(s):

Energy Intake ◽

Milk Production ◽

Milk Yield ◽

Milk Fat ◽

Block Design ◽

Parent Body ◽

Milk Quality ◽

Metabolizable Energy ◽

Increase Energy Intake ◽

Bali Cattle

To determine the effect of energy levels on digestible nutrient, milk production and milk quality of 7 months pregnant Bali cattle, was the purpose of this study. The study was conducted in Bali, Province of Indonesia on 12 pregnant breeding phase of pre-calving (2 months before the birth) with the parent body weight 329-340 kg/head. The treatment given is four types of Metabolizable Energy (ME) levels: 2000, 2100, 2200 and 2300/kg respectively as treatment A, B, C, and D. All ration contain 10% of crude protein. Variables measured: energy intake, digestible nutrient, milk yield, and milk quality. This research is a randomized block design. The results showed that increase energy ration until 2300 kcal ME/kg would significantly (P<0.05) increase energy intake and highest at cattle consumed ratio D is 22239.55 kcal/day. However, digestible nutrient was not affected. Milk production increased with increasing energy rations and highest (P<0.05) at cattle received treatment D is 2179.83 ml/day compared to treatment A 936.67 ml/day. Milk fat and milk lactose also highest (P<0.05) in treatment D are 8.56% and 4.76% respectively. Based on these results, it can be concluded that increase energy ration will increase energy intake, milk yield and milk fat and milk lactose of Bali cattle.

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Organic matter and water from asteroid Itokawa

Scientific Reports ◽

10.1038/s41598-021-84517-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Q. H. S. Chan ◽

A. Stephant ◽

I. A. Franchi ◽

X. Zhao ◽

R. Brunetto ◽

...

Keyword(s):

Organic Matter ◽

Solar System ◽

Parent Body ◽

Asteroid Belt ◽

True Nature ◽

Water Ice ◽

Nanocrystalline Graphite ◽

Terrestrial Water ◽

Solar System Bodies ◽

Small Dust

AbstractUnderstanding the true nature of extra-terrestrial water and organic matter that were present at the birth of our solar system, and their subsequent evolution, necessitates the study of pristine astromaterials. In this study, we have studied both the water and organic contents from a dust particle recovered from the surface of near-Earth asteroid 25143 Itokawa by the Hayabusa mission, which was the first mission that brought pristine asteroidal materials to Earth’s astromaterial collection. The organic matter is presented as both nanocrystalline graphite and disordered polyaromatic carbon with high D/H and 15N/14N ratios (δD = + 4868 ± 2288‰; δ15N = + 344 ± 20‰) signifying an explicit extra-terrestrial origin. The contrasting organic feature (graphitic and disordered) substantiates the rubble-pile asteroid model of Itokawa, and offers support for material mixing in the asteroid belt that occurred in scales from small dust infall to catastrophic impacts of large asteroidal parent bodies. Our analysis of Itokawa water indicates that the asteroid has incorporated D-poor water ice at the abundance on par with inner solar system bodies. The asteroid was metamorphosed and dehydrated on the formerly large asteroid, and was subsequently evolved via late-stage hydration, modified by D-enriched exogenous organics and water derived from a carbonaceous parent body.

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A Petrologic and Noble Gas Isotopic Study of New Basaltic Eucrite Grove Mountains 13001 from Antarctica

Minerals ◽

10.3390/min11030279 ◽

2021 ◽

Vol 11 (3) ◽

pp. 279

Author(s):

Chuantong Zhang ◽

Bingkui Miao ◽

Huaiyu He ◽

Hongyi Chen ◽

P. M. Ranjith ◽

...

Keyword(s):

Noble Gas ◽

Research Work ◽

Cosmic Ray ◽

Parent Body ◽

Chemical Compositions ◽

Isotopic Study ◽

Impact Processes ◽

Antarctic Research ◽

Formation And Evolution ◽

Grove Mountains

Howardite-Eucrite-Diogenite (HED) meteorite clan is a potential group of planetary materials which provides significant clues to understand the formation and evolution of the solar system. Grove Mountains (GRV) 13001 is a new member of HED meteorite, recovered from the Grove Mountains of Antarctica by the Chinese National Antarctic Research Expedition. This research work presents a comprehensive study of the petrology and mineralogy, chemical composition, noble gas isotopes, cosmic-ray exposure (CRE) age and nominal gas retention age for the meteorite GRV 13001. The output data indicate that GRV 13001 is a monomict basaltic eucrite with typical ophitic/subophitic texture, and it consists mainly of low-Ca pyroxene and plagioclase with normal eucritic chemical compositions. The noble gas based CRE age of the GRV 13001 is approximately 29.9 ± 3.0 Ma, which deviates from the major impact events or periods on the HED parent body. Additionally, the U,Th-4He and 40K-40Ar gas retention ages of this meteorite are ~2.5 to 4.0 Ga and ~3.6 to 4.1 Ga, respectively. Based on the noble gases isotopes and the corresponding ages, GRV 13001 may have experienced intense impact processes during brecciation, and weak thermal event after the ejection event at approximately 30 Ma.

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