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Newcombe ME, Nielsen SG, Peterson LD, Wang J, Alexander CMO, Sarafian AR, Shimizu K, Nittler LR, Irving AJ. Degassing of early-formed planetesimals restricted water delivery to Earth. Nature 2023; 615:854-857. [PMID: 36922597 DOI: 10.1038/s41586-023-05721-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 01/06/2023] [Indexed: 03/17/2023]
Abstract
The timing of delivery and the types of body that contributed volatiles to the terrestrial planets remain highly debated1,2. For example, it is unknown if differentiated bodies, such as that responsible for the Moon-forming giant impact, could have delivered substantial volatiles3,4 or if smaller, undifferentiated objects were more probable vehicles of water delivery5-7. Here we show that the water contents of minerals in achondrite meteorites (mantles or crusts of differentiated planetesimals) from both the inner and outer portions of the early Solar System are ≤2 μg g-1 H2O. These are among the lowest values ever reported for extraterrestrial minerals. Our results demonstrate that differentiated planetesimals efficiently degassed before or during melting. This finding implies that substantial amounts of water could only have been delivered to Earth by means of unmelted material.
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Affiliation(s)
| | - S G Nielsen
- NIRVANA Laboratories, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | | | - J Wang
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, USA
| | - C M O'D Alexander
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, USA
| | | | - K Shimizu
- University of Wisconsin, Madison, WI, USA
| | - L R Nittler
- Earth and Planets Laboratory, Carnegie Institution for Science, Washington, DC, USA
- School Of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA
| | - A J Irving
- University of Washington, Seattle, WA, USA
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2
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Goodrich CA, Sanborn ME, Yin QZ, Kohl I, Frank D, Daly RT, Walsh KJ, Zolensky ME, Young ERD, Jenniskens P, Shaddad MH. Chromium Isotopic Evidence for Mixing of NC and CC Reservoirs in Polymict Ureilites: Implications for Dynamical Models of the Early Solar System. THE PLANETARY SCIENCE JOURNAL 2021; 2:13. [PMID: 33681766 PMCID: PMC7931809 DOI: 10.3847/psj/abd258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Nucleosynthetic isotope anomalies show that the first few million years of solar system history were characterized by two distinct cosmochemical reservoirs, CC (carbonaceous chondrites and related differentiated meteorites) and NC (the terrestrial planets and all other groups of chondrites and differentiated meteorites), widely interpreted to correspond to the outer and inner solar system, respectively. At some point, however, bulk CC and NC materials became mixed, and several dynamical models offer explanations for how and when this occurred. We use xenoliths of CC materials in polymict ureilite (NC) breccias to test the applicability of such models. Polymict ureilites represent regolith on ureilitic asteroids but contain carbonaceous chondrite-like xenoliths. We present the first 54Cr isotope data for such clasts, which, combined with oxygen and hydrogen isotopes, show that they are unique CC materials that became mixed with NC materials in these breccias. It has been suggested that such xenoliths were implanted into ureilites by outer solar system bodies migrating into the inner solar system during the gaseous disk phase ~3-5 Myr after CAI, as in the "Grand Tack" model. However, combined textural, petrologic, and spectroscopic observations suggest that they were added to ureilitic regolith at ~50-60 Myr after CAI, along with ordinary, enstatite, and Rumuruti-type chondrites, as a result of breakup of multiple parent bodies in the asteroid belt at this time. This is consistent with models for an early instability of the giant planets. The C-type asteroids from which the xenoliths were derived were already present in inner solar system orbits.
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Affiliation(s)
- Cyrena A Goodrich
- Lunar and Planetary Institute, Universities Space Research Association, 3600 Bay Area Blvd, Houston, TX 77058 USA
| | - Matthew E Sanborn
- Department of Earth and Planetary Sciences, University of California at Davis, Davis, CA 95616 USA
| | - Qing-Zhu Yin
- Department of Earth and Planetary Sciences, University of California at Davis, Davis, CA 95616 USA
| | - Issaku Kohl
- Department of Earth and Planetary Sciences, University of California at Los Angeles, 595 Charles Young Drive East, Los Angeles, CA 90095 USA
| | - David Frank
- Hawai'i Institute of Geophysics and Planetology, Department of Earth Sciences, University of Hawai'i at Mānoa, Honolulu HI 96822 USA
| | - R Terik Daly
- The Johns Hopkins University Applied Physics Laboratory 11100 Johns Hopkins Road
| | - Kevin J Walsh
- Southwest Research Institute, 1050 Walnut St. Suite 300, Boulder, CO 80302 USA
| | - Michael E Zolensky
- Astromaterials Research and Exploration Science, NASA-Johnson Space Center Houston, TX 77058 USA
| | - Edward R D Young
- Department of Earth and Planetary Sciences, University of California at Los Angeles, 595 Charles Young Drive East, Los Angeles, CA 90095 USA
| | | | - Muawia H Shaddad
- Physics Department, University of Khartoum, Khartoum 11115 Sudan
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3
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Weiss BP, Bai XN, Fu RR. History of the solar nebula from meteorite paleomagnetism. SCIENCE ADVANCES 2021; 7:7/1/eaba5967. [PMID: 33523830 PMCID: PMC7775786 DOI: 10.1126/sciadv.aba5967] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 11/10/2020] [Indexed: 06/02/2023]
Abstract
We review recent advances in our understanding of magnetism in the solar nebula and protoplanetary disks (PPDs). We discuss the implications of theory, meteorite measurements, and astronomical observations for planetary formation and nebular evolution. Paleomagnetic measurements indicate the presence of fields of 0.54 ± 0.21 G at ~1 to 3 astronomical units (AU) from the Sun and ≳0.06 G at 3 to 7 AU until >1.22 and >2.51 million years (Ma) after solar system formation, respectively. These intensities are consistent with those predicted to enable typical astronomically observed protostellar accretion rates of ~10-8 M ⊙year-1, suggesting that magnetism played a central role in mass transport in PPDs. Paleomagnetic studies also indicate fields <0.006 G and <0.003 G in the inner and outer solar system by 3.94 and 4.89 Ma, respectively, consistent with the nebular gas having dispersed by this time. This is similar to the observed lifetimes of extrasolar protoplanetary disks.
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Affiliation(s)
- Benjamin P Weiss
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Xue-Ning Bai
- Institute for Advanced Study and Department of Astronomy, Tsinghua University, Beijing, China.
| | - Roger R Fu
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
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4
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Yang J, Zhou J, Lin PT. Real-time isotopic methane detection using mid-infrared spectroscopy. APPLIED OPTICS 2020; 59:10801-10807. [PMID: 33361900 DOI: 10.1364/ao.405556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/29/2020] [Indexed: 06/12/2023]
Abstract
A real-time, nondestructive mid-infrared (mid-IR) platform was proposed for isotopic methane detection. The measurement system consisted of a tunable mid-IR laser, a miniaturized gas chamber, and a mid-IR signal receiver. The isotope ratio of the 12CH4/13CH4 was identified by measuring the mid-IR spectrum at λ=3.2-3.5µm.In-situ12CH4/13CH4 monitoring was then achieved by tracing the characteristic mid-IR absorption peaks assigned to the 12CH4 at λ=3.328µm and 13CH4 at λ=3.340µm. The real-time methane isotope analysis can be applied to environmental monitoring and petroleum industries.
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5
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Williams CD, Sanborn ME, Defouilloy C, Yin QZ, Kita NT, Ebel DS, Yamakawa A, Yamashita K. Chondrules reveal large-scale outward transport of inner Solar System materials in the protoplanetary disk. Proc Natl Acad Sci U S A 2020; 117:23426-23435. [PMID: 32900966 PMCID: PMC7519341 DOI: 10.1073/pnas.2005235117] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dynamic models of the protoplanetary disk indicate there should be large-scale material transport in and out of the inner Solar System, but direct evidence for such transport is scarce. Here we show that the ε50Ti-ε54Cr-Δ17O systematics of large individual chondrules, which typically formed 2 to 3 My after the formation of the first solids in the Solar System, indicate certain meteorites (CV and CK chondrites) that formed in the outer Solar System accreted an assortment of both inner and outer Solar System materials, as well as material previously unidentified through the analysis of bulk meteorites. Mixing with primordial refractory components reveals a "missing reservoir" that bridges the gap between inner and outer Solar System materials. We also observe chondrules with positive ε50Ti and ε54Cr plot with a constant offset below the primitive chondrule mineral line (PCM), indicating that they are on the slope ∼1.0 in the oxygen three-isotope diagram. In contrast, chondrules with negative ε50Ti and ε54Cr increasingly deviate above from PCM line with increasing δ18O, suggesting that they are on a mixing trend with an ordinary chondrite-like isotope reservoir. Furthermore, the Δ17O-Mg# systematics of these chondrules indicate they formed in environments characterized by distinct abundances of dust and H2O ice. We posit that large-scale outward transport of nominally inner Solar System materials most likely occurred along the midplane associated with a viscously evolving disk and that CV and CK chondrules formed in local regions of enhanced gas pressure and dust density created by the formation of Jupiter.
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Affiliation(s)
- Curtis D Williams
- Department of Earth and Planetary Sciences, University of California, Davis, CA 95616;
| | - Matthew E Sanborn
- Department of Earth and Planetary Sciences, University of California, Davis, CA 95616
| | - Céline Defouilloy
- WiscSIMS, Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706
| | - Qing-Zhu Yin
- Department of Earth and Planetary Sciences, University of California, Davis, CA 95616;
| | - Noriko T Kita
- WiscSIMS, Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706
| | - Denton S Ebel
- Department of Earth and Planetary Sciences, American Museum of Natural History, New York, NY 10024
| | - Akane Yamakawa
- Department of Earth and Planetary Sciences, University of California, Davis, CA 95616
| | - Katsuyuki Yamashita
- Graduate School of Natural Science and Technology, Okayama University, Kita-ku, 700-8530 Okayama, Japan
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6
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Fukuda K, Beard BL, Dunlap DR, Spicuzza MJ, Fournelle JH, Wadhwa M, Kita NT. Magnesium isotope analysis of olivine and pyroxene by SIMS: Evaluation of matrix effects. CHEMICAL GEOLOGY 2020; 540:119482. [PMID: 34866642 PMCID: PMC8637499 DOI: 10.1016/j.chemgeo.2020.119482] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The performance of multi-collector secondary ion mass spectrometry (MC-SIMS) for Mg isotope ratio analysis was evaluated using 17 olivine and 5 pyroxene reference materials (RMs). The Mg isotope composition of these RMs was accurately and precisely determined by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS), and these measured isotope ratios were used to evaluate SIMS instrumental mass bias as a function of the forsterite (Fo) content of olivine. The magnitude of the Mg isotope matrix effects were ~3‰ in δ25Mg, and are a complex function of olivine Fo content, that ranged from Fo59.3 to Fo100. In addition to these Mg isotope matrix effects, Si+ ion yields and Mg+/Si+ ion ratios varied as a complex function of the Fo content of the olivine RMs. For example, Si+ ion yields varied by ~33%. Based on the observations, we propose instrumental bias correction procedures for SIMS Mg isotope analysis of olivine using a combination of Mg+/Si+ ratios and Fo content of olivine. Using this correction method, the accuracy of δ25Mg analyses is 0.3‰, except for analysis of olivine with Fo86-88 where instrumental biases and Mg+/Si+ ratios change dramatically with Fo content, making it more difficult to assess the accuracy of Mg isotope ratio measurements by SIMS over this narrow range of Fo content. Five pyroxene RMs (3 orthopyroxenes and 2 clinopyroxenes) show smaller ranges of instrumental bias (~1.4‰ in δ25Mg) as compared to the olivine RMs. The instrumental bias for the 3 orthopyroxene RMs do not define a linear relationship with respect to enstatite (En) content, that ranged from En85.5 -96.3. The clinopyroxene RMs have similar En and wollastonite (Wo) contents but have δ25Mg values that differ by 0.5‰ relative to their δ25Mg values determined by MC-ICP-MS. These results indicate that additional factors (e.g., minor element abundances) likely contribute to SIMS instrumental mass fractionation. In order to better correct for these SIMS matrix effects, additional pyroxene RMs with various chemical compositions and known Mg isotope ratios are needed.
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Affiliation(s)
- Kohei Fukuda
- Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Brian L. Beard
- Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Daniel R. Dunlap
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, USA
| | - Michael J. Spicuzza
- Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - John H. Fournelle
- Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Meenakshi Wadhwa
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, USA
| | - Noriko T. Kita
- Department of Geoscience, University of Wisconsin-Madison, Madison, WI 53706, USA
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7
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Allegretta I, Marangoni B, Manzari P, Porfido C, Terzano R, De Pascale O, Senesi GS. Macro-classification of meteorites by portable energy dispersive X-ray fluorescence spectroscopy (pED-XRF), principal component analysis (PCA) and machine learning algorithms. Talanta 2020; 212:120785. [PMID: 32113548 DOI: 10.1016/j.talanta.2020.120785] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 01/21/2020] [Accepted: 01/25/2020] [Indexed: 11/16/2022]
Abstract
The research on meteorites from hot and cold deserts is gaining advantages from the recent improvements of portable technologies such as X-ray fluorescence spectroscopy (XRF). The main advantages of portable instruments include the fast recognition of meteorites through their classification in macro-groups and discrimination from materials such as industrial slags, desert varnish covered rocks and iron oxides, named "meteor-wrongs". In this study, 18 meteorite samples of different nature and origin were discriminated and preliminarily classified into characteristic macro-groups: iron meteorites, stony meteorites and meteor-wrongs, combining a portable energy dispersive XRF instrument (pED-XRF), principal component analysis (PCA) and some machine learning algorithms applied to the XRF spectra. The results showed that 100% accuracy in sample classification was obtained by applying the cubic support vector machine (CSVM), fine kernel nearest neighbor (FKNN), subspace discriminant-ensemble classifiers (SD-EC) and subspace discriminant KNN-EC (SKNN-EC) algorithms on standardized spectra.
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Affiliation(s)
- Ignazio Allegretta
- Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, Università degli Studi di Bari "Aldo Moro", Via Amendola 165/A, 70126, Bari, Italy
| | - Bruno Marangoni
- Physics Institute, Federal University of Mato Grosso do Sul, P.O. Box 549, Campo Grande, MS, 79070-900, Brazil
| | - Paola Manzari
- Agenzia Spaziale Italiana, via del Politecnico, 00133, Roma, Italy
| | - Carlo Porfido
- Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, Università degli Studi di Bari "Aldo Moro", Via Amendola 165/A, 70126, Bari, Italy
| | - Roberto Terzano
- Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, Università degli Studi di Bari "Aldo Moro", Via Amendola 165/A, 70126, Bari, Italy
| | - Olga De Pascale
- CNR - Istituto per la Scienza e Tecnologia dei Plasmi (ISTP) - Sede di Bari, Via Amendola 122/D, 70126, Bari, Italy
| | - Giorgio S Senesi
- CNR - Istituto per la Scienza e Tecnologia dei Plasmi (ISTP) - Sede di Bari, Via Amendola 122/D, 70126, Bari, Italy.
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8
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Goodrich CA, Zolensky ME, Fioretti AM, Shaddad MH, Downes H, Hiroi T, Kohl I, Young ED, Kita NT, Hamilton VE, Riebe MEI, Busemann H, Macke RJ, Fries M, Ross DK, Jenniskens P. The First Samples from Almahata Sitta Showing Contacts Between Ureilitic and Chondritic Lithologies: Implications for the Structure and Composition of Asteroid 2008 TC 3. METEORITICS & PLANETARY SCIENCE 2019; 54:2769-2813. [PMID: 33716489 PMCID: PMC7954227 DOI: 10.1111/maps.13390] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 08/17/2019] [Indexed: 06/12/2023]
Abstract
Almahata Sitta (AhS), an anomalous polymict ureilite, is the first meteorite observed to originate from a spectrally classified asteroid (2008 TC3). However, correlating properties of the meteorite with those of the asteroid is not straightforward because the AhS stones are diverse types. Of those studied prior to this work, 70-80% are ureilites (achondrites) and 20-30% are various types of chondrites. Asteroid 2008 TC3 was a heterogeneous breccia that disintegrated in the atmosphere, with its clasts landing on Earth as individual stones and most of its mass lost. We describe AhS 91A and AhS 671, which are the first AhS stones to show contacts between ureilitic and chondritic materials and provide direct information about the structure and composition of asteroid 2008 TC3. AhS 91A and AhS 671 are friable breccias, consisting of a C1 lithology that encloses rounded to angular clasts (<10 μm to 3 mm) of olivine, pyroxenes, plagioclase, graphite, and metal-sulfide, as well as chondrules (~130-600 μm) and chondrule fragments. The C1 material consists of fine-grained phyllosilicates (serpentine and saponite) and amorphous material, magnetite, breunnerite, dolomite, fayalitic olivine (Fo 28-42), an unidentified Ca-rich silicate phase, Fe,Ni sulfides, and minor Ca-phosphate and ilmenite. It has similarities to CI1 but shows evidence of heterogeneous thermal metamorphism. Its bulk oxygen isotope composition (δ18O = 13.53‰, δ17O = 8.93‰) is unlike that of any known chondrite, but similar to compositions of several CC-like clasts in typical polymict ureilites. Its Cr isotope composition is unlike that of any known meteorite. The enclosed clasts and chondrules do not belong to the C1 lithology. The olivine (Fo 75-88), pyroxenes (pigeonite of Wo ~10 and orthopyroxene of Wo ~4.6), plagioclase, graphite, and some metal-sulfide are ureilitic, based on mineral compositions, textures, and oxygen isotope compositions, and represent at least six distinct ureilitic lithologies. The chondrules are probably derived from type 3 OC and/or CC, based on mineral and oxygen isotope compositions. Some of the metal-sulfide clasts are derived from EC. AhS 91A and AhS 671 are plausible representatives of the bulk of the asteroid that was lost. Reflectance spectra of AhS 91A are dark (reflectance ~0.04-0.05) and relatively featureless in VNIR, and have an ~2.7 μm absorption band due to OH- in phyllosilicates. Spectral modeling, using mixtures of laboratory VNIR reflectance spectra of AhS stones to fit the F-type spectrum of the asteroid, suggests that 2008 TC3 consisted mainly of ureilitic and AhS 91A-like materials, with as much as 40-70% of the latter, and <10% of OC, EC and other meteorite types. The bulk density of AhS 91A (2.35 ± 0.05 g/cm3) is lower than bulk densities of other AhS stones, and closer to estimates for the asteroid (~1.7-2.2 g/cm3). Its porosity (36%) is near the low end of estimates for the asteroid (33-50%), suggesting significant macroporosity. The textures of AhS 91A and AhS 671 (finely comminuted clasts of disparate materials intimately mixed) support formation of 2008 TC3 in a regolith environment. AhS 91A and AhS 671 could represent a volume of regolith formed when a CC-like body impacted into already well-gardened ureilitic + impactor-derived debris. AhS 91A bulk samples do not show a solar wind (SW) component, so they represent sub-surface layers. AhS 91A has a lower cosmic ray exposure (CRE) age (~5-9 Ma) than previously studied AhS stones (11-22 Ma). The spread in CRE ages argues for irradiation in a regolith environment. AhS 91A and AhS 671 show that ureilitic asteroids could have detectable ~2.7 μm absorption bands.
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Affiliation(s)
- Cyrena Anne Goodrich
- Lunar and Planetary Institute, Universities Space Research Association, 3600 Bay Area Blvd, Houston, TX 77058 USA
| | - Michael E Zolensky
- Astromaterials Research and Exploration Science, NASA-Johnson Space Center Houston, TX 77058 USA
| | | | - Muawia H Shaddad
- Physics Department, University of Khartoum, Khartoum 11115 Sudan
| | - Hilary Downes
- Department of Earth and Planetary Sciences, Birkbeck, University of London, Malet Street, Bloomsbury, London WC1E 7HX UK
| | - Takahiro Hiroi
- Department of Geological Sciences, Brown University, Providence, RI 02912, USA
| | - Issaku Kohl
- Department of Earth and Planetary Sciences, University of California at Los Angeles, 595 Charles Young Drive East, Los Angeles, CA 90095 USA
| | - Edward D Young
- Department of Earth and Planetary Sciences, University of California at Los Angeles, 595 Charles Young Drive East, Los Angeles, CA 90095 USA
| | - Noriko T Kita
- Wisc-SIMS Laboratory, Department of Geoscience, University of Wisconsin-Madison, 1215 West Dayton Street, Madison, WI 53706 USA
| | - Victoria E Hamilton
- Department of Space Studies, Southwest Research Institute, 1050 Walnut St., Suite 300, Boulder Colorado 80302 USA
| | - My E I Riebe
- Department of Terrestrial Magnetism, Carnegie Institution for Science, 5241 Broad Branch Rd NW, Washington, DC 20015, USA
- Institute for Geochemistry and Petrology, ETH Zürich, Clausiusstrasse 25, CH-8092 Zürich, Switzerland
| | - Henner Busemann
- Institute for Geochemistry and Petrology, ETH Zürich, Clausiusstrasse 25, CH-8092 Zürich, Switzerland
| | | | - M Fries
- Astromaterials Research and Exploration Science, NASA-Johnson Space Center Houston, TX 77058 USA
| | - D Kent Ross
- Jacobs-JETS, University of Texas at El Paso, at NASA-JSC, Houston, TX 77058 USA
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9
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Archer GJ, Walker RJ, Irving AJ. Highly siderophile element and 187Re- 187Os isotopic systematics of ungrouped achondrite Northwest Africa 7325: Evidence for complex planetary processes. GEOCHIMICA ET COSMOCHIMICA ACTA 2019; 54:1042-1050. [PMID: 34316080 PMCID: PMC8312601 DOI: 10.1111/maps.13261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 01/21/2019] [Indexed: 06/13/2023]
Abstract
The abundances of highly siderophile elements (HSE; including Re, Os, Ir, Ru, Pt, and Pd) and 187Re-187Os isotopic systematics were determined for two fragments from ungrouped achondrite NWA 7325. Rhenium-Os systematics are consistent with closed-system behavior since formation or soon after. The abundances of the HSE were therefore largely unaffected by late-stage secondary processes such as shock or terrestrial weathering. As an olivine gabbro cumulate, this meteorite has a bulk composition consistent with derivation from a body that produced a core, mantle and crust. Also consistent with derivation from a body that produced a core, both fragments of NWA 7325 have HSE abundances that are highly depleted compared to bulk chondrites. One fragment has ~0.002 × CI chondrite Ir and relative HSE abundances similar to bulk chondrites. The other fragment has ~0.0002 × CI chondrite Ir, and relative HSE abundances that are fractionated compared to bulk chondrites. The chondritic relative HSE abundances of the fragment characterized by higher HSE abundances most likely reflect the addition of exogenous chondritic material during or after crystallization by surface impacts. The HSE in the other fragment is likely more representative of the parent body crust. One formation model that can broadly account for the HSE abundances in this fragment is multiple episodes of low-pressure metal-silicate equilibration, followed by limited late accretion and mantle homogenization. Given the different HSE compositions of the two adjoining fragments, this meteorite provides an example of the overprint of global processes (differentiation and late accretion) by localized impact contamination.
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Affiliation(s)
- Gregory J. Archer
- Department of Geology, University of Maryland, College Park, MD 20742, USA
- Institut für Planetologie, University of Münster, Münster 48149, Germany
| | - Richard J. Walker
- Department of Geology, University of Maryland, College Park, MD 20742, USA
| | - Anthony J. Irving
- Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195, USA
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10
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Srinivasan P, Dunlap DR, Agee CB, Wadhwa M, Coleff D, Ziegler K, Zeigler R, McCubbin FM. Silica-rich volcanism in the early solar system dated at 4.565 Ga. Nat Commun 2018; 9:3036. [PMID: 30072693 PMCID: PMC6072707 DOI: 10.1038/s41467-018-05501-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 07/03/2018] [Indexed: 11/09/2022] Open
Abstract
The ranges in chemical composition of ancient achondrite meteorites are key to understanding the diversity and geochemical evolution of planetary building blocks. These achondrites record the first episodes of volcanism and crust formation, the majority of which are basaltic. Here we report data on recently discovered volcanic meteorite Northwest Africa (NWA) 11119, which represents the first, and oldest, silica-rich (andesitic to dacitic) porphyritic extrusive crustal rock with an Al-Mg age of 4564.8 ± 0.3 Ma. This unique rock contains mm-sized vesicles/cavities and phenocrysts that are surrounded by quench melt. Additionally, it possesses the highest modal abundance (30 vol%) of free silica (i.e., tridymite) compared to all known meteorites. NWA 11119 substantially widens the range of volcanic rock compositions produced within the first 2.5-3.5 million years of Solar System history, and provides direct evidence that chemically evolved crustal rocks were forming on planetesimals prior to the assembly of the terrestrial planets.
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Affiliation(s)
- Poorna Srinivasan
- Institute of Meteoritics, University of New Mexico, Albuquerque, NM, 87131, USA.
- Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM, 87131, USA.
| | - Daniel R Dunlap
- Center for Meteorite Studies, School of Earth and Space Exploration, Arizona State University, Tempe, AZ, 85287, USA
| | - Carl B Agee
- Institute of Meteoritics, University of New Mexico, Albuquerque, NM, 87131, USA
- Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Meenakshi Wadhwa
- Center for Meteorite Studies, School of Earth and Space Exploration, Arizona State University, Tempe, AZ, 85287, USA
| | - Daniel Coleff
- Jacobs Technology, NASA Johnson Space Center, Mail Code XI3, 2101 NASA Parkway, Houston, TX, 77058, USA
| | - Karen Ziegler
- Institute of Meteoritics, University of New Mexico, Albuquerque, NM, 87131, USA
- Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Ryan Zeigler
- NASA Johnson Space Center, Mail Code XI2, 2101 NASA Parkway, Houston, TX, 77058, USA
| | - Francis M McCubbin
- NASA Johnson Space Center, Mail Code XI2, 2101 NASA Parkway, Houston, TX, 77058, USA
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Scott ERD, Krot AN, Sanders IS. Isotopic Dichotomy among Meteorites and Its Bearing on the Protoplanetary Disk. THE ASTROPHYSICAL JOURNAL 2018; 854:164. [PMID: 30842684 PMCID: PMC6398615 DOI: 10.3847/1538-4357/aaa5a5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Whole rock Δ17O and nucleosynthetic isotopic variations for chromium, titanium, nickel, and molybdenum in meteorites define two isotopically distinct populations: carbonaceous chondrites (CCs) and some achondrites, pallasites, and irons in one and all other chondrites and differentiated meteorites in the other. Since differentiated bodies accreted 1-3 Myr before the chondrites, the isotopic dichotomy cannot be attributed to temporal variations in the disk. Instead, the two populations were most likely separated in space, plausibly by proto-Jupiter. Formation of CCs outside Jupiter could account for their characteristic chemical and isotopic composition. The abundance of refractory inclusions in CCs can be explained if they were ejected by disk winds from near the Sun to the disk periphery where they spiraled inward due to gas drag. Once proto-Jupiter reached 10-20 M ⊕, its external pressure bump could have prevented millimeter- and centimeter-sized particles from reaching the inner disk. This scenario would account for the enrichment in CCs of refractory inclusions, refractory elements, and water. Chondrules in CCs show wide ranges in Δ17O as they formed in the presence of abundant 16O-rich refractory grains and 16O-poor ice particles. Chondrules in other chondrites (ordinary, E, R, and K groups) show relatively uniform, near-zero Δ17O values as refractory inclusions and ice were much less abundant in the inner solar system. The two populations were plausibly mixed together by the Grand Tack when Jupiter and Saturn migrated inward emptying and then repopulating the asteroid belt with roughly equal masses of planetesimals from inside and outside Jupiter's orbit (S- and C-type asteroids).
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Affiliation(s)
- Edward R D Scott
- Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, Honolulu, HI 96822, USA
| | - Alexander N Krot
- Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, Honolulu, HI 96822, USA
| | - Ian S Sanders
- Department of Geology, Trinity College, Dublin 2, Ireland
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