The chemical composition of metallic spheroids and metallic particles within impactite from Barringer Meteorite Crater, Arizona

Kelly, William R.; Holdsworth, Edward; Moore, C. B.

doi:10.1016/0016-7037(74)90039-8

Cited by 33 publications

(37 citation statements)

References 11 publications

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“…We conclude that the spheroids did not condense from a gas that formed when the projectile vaporized because it is hard to imagine how the spheroids could have recaptured the cosmogenic gases. Blau et al (1973) and Kelly et al (1974) reached the same conclusion based on different kinds of compositional evidence. The widespread presence of cosmogenic 38Ar in Canyon Diablo spheroids strongly suggests but does not prove that they contain very little material from the interior portions ofthe projectile, where virtually no production of 38Ar occurs.…”

Section: Discussionsupporting

confidence: 48%

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Pre‐atmospheric depths and thermal histories of Canyon Diablo spheroids

Leya

Wieler

Peng

et al. 2002

Meteorit & Planetary Scien

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Abstract-Despite having melted during formation, seven of eight Canyon Diablo spheroids weighing from 0.6 to 13 mg retain cosmic-ray-produced 38Ar (38Arcos) in concentrations (10-10 cm-' STP/g) ranging from 0.35 to 68. The presence of3 8Arcos is consistent with pre-atmospheric depths of<2.3 m and most likely rules out an origin for the spheroids deep within the projectile, which had a radius of 15 m. Low levels of 21Necos indicate gas loss from these spheroids. Relative to most Canyon Diablo meteorites, the spheroids contain lower concentrations of cosmogenic noble gases. The difference partly reflects diffusion losses from the spheroids, especially for 3He and 21Ne, but also suggests deeper locations on average for the precursor material, consistent with independent results from 59Ni.

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Section: Discussionsupporting

confidence: 48%

“…Nininger speculated that the spheroids condensed from a vapor cloud as fiery rain. Several authors have argued against this speculation (Kelly et al, 1974;Blau et al, 1973;Mittlefehldt et al, 1994), suggesting instead that the spheroids formed from a liquid generated either by atmospheric friction and/or by shock melting on impact.…”

Section: Introductionmentioning

confidence: 99%

Pre‐atmospheric depths and thermal histories of Canyon Diablo spheroids

Leya

Wieler

Peng

et al. 2002

Meteorit & Planetary Scien

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“…Note the distinct gap at~12 to 20% total FeO + NiO, suggesting a bi-moda1 distribution ofprojectile-derived melt components. These meteorite concentrations represent minimum values because we diligently excluded small metallic opaques from the analyses; such opaques are abundant, occur in a wide range ofsizes, and have diverse compositions and mineralogies (Brett, 1967;Kelly et al, 1974). A summary of the distribution of meteorite-derived Ni and Fe is presented in Fig.…”

Section: Clear Glassesmentioning

confidence: 99%

“…Our measurements carefully avoided the numerous, fmely dispersed opaques that occur throughout these melts and that represent additional projectile material (Brett, 1967;Kelly et al, 1974). These metallic particles tend to be rich in Ni, and pure Ni-sulfides are common.…”

Section: Dissemination Of the Projectilementioning

confidence: 99%

“…For most craters, it is not possible to reconstruct the pre-impact stratigraphy with sufficient The first descriptions of the melts from Meteor Crater are by Nininger (1954Nininger ( , 1956, who details their field occurrence, the diverse morphologies, their chemical bulk composition, and who first identified them as ballistically transported melt-spray. Most subsequent compositional studies of these melts addressed the dissemination of the iron-meteorite projectile (Morgan et al, 1975), or chemical fractionation of the projectile during impact-induced melting (e.g., Brett, 1967;Kelly et al, 1974).…”

Section: Introductionmentioning

confidence: 99%

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Petrographic studies of the impact melts from Meteor Crater, Arizona, USA

Hörz

Mittlefehldt

See

et al. 2002

Meteorit & Planetary Scien

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Abstract-We investigated the ballistically dispersed melts from Meteor Crater, Arizona, USA to determine the stratigraphic extent of its melt zone from the compositional relationship of melts and target rocks. Most melt particles are crystallized, hydrated, and oxidized; pristine glasses are rare. Hydration and oxidation occurred at ambient temperatures long after the impact. The preserved glasses are generally clear and texturally homogeneous, but unlike typical impact melts, they have unusually heterogeneous compositions, both within individual particles and from sample to sample. For example, the average Si0 2 for individual particles ranges from 43 to 65%. The projectile content is unusually high and it is distributed bimodally, with specific samples containing either 5-10% or 20-30% FeO. These compositional heterogeneities most likely reflect the high carbonate content of the target rocks and the release of copious COz that dispersed the melts, thereby terminating melt flow and mixing. The high projectile content and the COz depleted residue of purely sedimentary rocks produced mafic melts that crystallized fine-grained olivine and pyroxene.The melts fall into three compositional groups reflecting variable proportions of the major target formations, Moenkopi, Kaibab, and Coconino. Least-square mixing calculations revealed one group to contain 55% Moenkopi, 40% quartz-rich, upper Kaibab, and 5% meteorite, suggesting a source depth of <30 m from the pre-impact surface. The other two melt groups have higher contents of meteorite (15-20%) and Kaibab (50-70%) and contain more SiOz than average Kaibab. The additional quartz may have been derived from Coconino or the upper Kaibab, implying melt depths >90 m or <30 m, respectively. Additional studies, especially hydrocode calculations, are needed to better understand the source depth ofthese melts and their exceptionally high projectile content.

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FeNi metal in impact melt rocks of Lake Lappaj�rvi, Finland

Fregerslev

Carstens

1976

Contr. Mineral. and Petrol.

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The chemical composition of metallic spheroids and metallic particles within impactite from Barringer Meteorite Crater, Arizona

Cited by 33 publications

References 11 publications

Pre‐atmospheric depths and thermal histories of Canyon Diablo spheroids

Pre‐atmospheric depths and thermal histories of Canyon Diablo spheroids

Petrographic studies of the impact melts from Meteor Crater, Arizona, USA

FeNi metal in impact melt rocks of Lake Lappaj�rvi, Finland

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