Isotopic compositions of oxygen, iron, chromium, and nickel in cosmic spherules: Toward a better comprehension of atmospheric entry heating effects

Engrand, C.; McKeegan, Kevin D.; Leshin, L. A.; Herzog, G. F.; Schnabel, Christoph; Nyquist, L. E.; Brownlee, D. E.

doi:10.1016/j.gca.2005.07.002

Cited by 70 publications

(140 citation statements)

References 37 publications

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“…Oxygen isotope data indicate that some micrometeorites derive from parent bodies similar to those of known carbonaceous chondrites (Yada et al 2005;Taylor et al 2005;Engrand et al 2005), while others come from parent bodies not represented in the conventional collections (Yada et al 2005;Matrajt et al 2006). Based primarily on the oxygen isotope evidence, we conclude that the micrometeorites sample a broader range, and perhaps a larger number of parent bodies, than do conventional meteorites.…”

Section: Different Parent Bodies For Micrometeorites and Conventionalmentioning

confidence: 80%

Crumbs from the crust of Vesta: Achondritic cosmic spherules from the South Pole water well

Taylor

Herzog

Delaney

2007

Meteorit & Planetary Scien

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Abstract-Ten glass cosmic spherules (CS) from the South Pole water well collection were analyzed by electron microprobe. Nine of them have Fe/Mn and Fe/Mg ratios in the range typical of chondrites. One of them (SP37-3), along with up to six other previously analyzed CS, have nonchondritic Fe/Mn and Fe/Mg ratios that agree well with values typical of either (basaltic) howardite, eucrite, and diogenite (HED) meteorites or Martian basalts, but not of lunar samples. SP37-3 also contains an anorthite relic grain. Anorthite has not previously been reported in cosmic spherules, but is well known in HED meteorites. The much greater frequency of HEDs among hand-sized meteorites suggests but does not prove that HED precursors are more likely for the nonchondritic spherules.We estimate that HED-like micrometeorites constitute ~0.5 ± 0.4% of the total population of micrometeorites in the South Pole water well, a fraction that translates to a flux of 1.6 ± 0.3 × 10 −8 g HED micrometeorites/m 2 -y. The ratio of HED-like objects to carbonaceous objects is about 100 times less in micrometeorites than among hand-size specimens. We infer that the comparative mechanical weakness of carbonaceous precursor materials tends to encourage spherule formation.

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Section: Different Parent Bodies For Micrometeorites and Conventionalmentioning

confidence: 80%

Crumbs from the crust of Vesta: Achondritic cosmic spherules from the South Pole water well

Taylor

Herzog

Delaney

2007

Meteorit & Planetary Scien

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“…Ironrich industrial/diesel spherules are, for example, very common in the terrestrial environment and many consist primarily of magnetite and are thus mineralogically indistinguishable from some melted micrometeorites. Isotopic data of iron-rich spherules recovered from the deep sea have confirmed their extraterrestrial origins (Clayton et al 1986;Engrand et al 1998Engrand et al , 2005Herzog et al 1999;Raisbeck and Yiou 1989). These make up a large fraction of the deep sea spherules (25 to 50%), but are present in abundances of a few percent in polar regions (Genge et al 1997a;Taylor et al 1998).…”

Section: Non-isotopic Criteria For Extraterrestrial Originmentioning

confidence: 81%

The classification of micrometeorites

Genge

Engrand

Gounelle

et al. 2008

Meteorit & Planetary Scien

219

373

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Abstract-Due to their small size, the mineralogical and chemical properties of micrometeorites (MMs) are not representative of their parent bodies on the centimeter to meter scales that are used to define parent body groups through the petrological study of meteorites. Identifying which groups of MM are derived from the same type of parent body is problematic and requires particles to be rigorously grouped on the basis of mineralogical, textural, and chemical properties that reflect the fundamental genetic differences between meteorite parent bodies, albeit with minimal bias towards preconceived genetic models. Specifically, the interpretation of MMs requires a rigorous and meaningful classification scheme. At present the classification of MMs is, however, at best ambiguous. A unified petrological-chemical classification scheme is proposed in the current study and is based on observations of several thousand MMs collected from Antarctic ice.

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“…-There are evidences of an invariance of the composition of the flux of micrometeorites as a function of time [20][21][22][23] or toward smaller sizes [24; 25].…”

Section: Interplanetary Dust As Representative Sampling Of Interplanementioning

confidence: 99%

Cometary micrometeorites and input of prebiotic compounds

Engrand

2014

BIO Web of Conferences

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Abstract. The apparition of life on the early Earth was probably favored by inputs of extraterrestrial matter brought by carbonaceous chondrite-like objects or cometary material. Interplanetary dust collected nowadays on Earth is related to carbonaceous chondrites and to cometary material. They contain in particular at least a few percent of organic matter, organic compounds (amino-acids, PAHs,…), hydrous silicates, and could have largely contributed to the budget of prebiotic matter on Earth, about 4 Ga ago. A new population of cometary dust was recently discovered in the Concordia Antarctic micrometeorite collection. These "Ultracarbonaceous Antarctic Micrometeorites" (UCAMMs) are dominated by deuterium-rich and nitrogen-rich organic matter. They seem related to the "CHON" grains identified in the comet Halley in 1986. Although rare in the micrometeorites flux (<5% of the micrometeorites), UCAMMs could have significantly contributed to the input of prebiotic matter. Their content in soluble organic matter is currently under study.

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Isotopic compositions of oxygen, iron, chromium, and nickel in cosmic spherules: Toward a better comprehension of atmospheric entry heating effects

Cited by 70 publications

References 37 publications

Crumbs from the crust of Vesta: Achondritic cosmic spherules from the South Pole water well

Crumbs from the crust of Vesta: Achondritic cosmic spherules from the South Pole water well

The classification of micrometeorites

Cometary micrometeorites and input of prebiotic compounds

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