Study of a set of micrometeorites from Antarctica using magnetic and ESR methods coupled with micro-XRF

Marfaing, J.; Rochette, P.; Pellerey, J.; Chaurand, Perrine; Suavet, C.; Folco, Luigi

doi:10.1016/j.jmmm.2008.01.037

Cited by 3 publications

(4 citation statements)

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“…I‐type (iron) CSs contain iron oxides wüstite and magnetite [ Genge et al , 2008] (Figure 2, samples Ia–Ie). In rare cases metal cores have been described, but none were observed in this study or in that of Marfaing et al [2008].…”

Section: Characterization Of Micrometeoritescontrasting

confidence: 51%

“…In this study, we measured the magnetic properties of 506 MM from different locations in Antarctica (490 CSs, 6 ScMMs, 7 FgMMs and 2 CgMMs), and 14 CSs from other origins (Greenland lake sediments and Pacific Ocean sediments). This is the first study of this kind, besides the measurement of 14 Iron‐type cosmic spherules by Marfaing et al [2008]. Owing to their continuous influx, MMs are a minor constituent of every surface material on Earth.…”

Section: Introductionmentioning

confidence: 92%

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Magnetic properties of micrometeorites

et al. 2009

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[1] Most micrometeorites are strongly magnetic: the signal of a single micrometeorite may exceed the signal of a weakly magnetized standard sediment sample. Micrometeorites contain abundant magnetite, mostly produced by high-temperature oxidation during atmospheric entry. In this study, we carried out measurements on 520 micrometeorites (505 melted cosmic spherules, 6 partially melted scoriaceous micrometeorites, and 9 unmelted micrometeorites). The natural remanent magnetization and the saturation isothermal remanent magnetization have been measured, followed by alternating field or thermal stepwise demagnetization. The natural remanent magnetization is in the range of 0.4-300 A/m for cosmic spherules; it is a stable thermal remanent magnetization acquired by quenching in the Earth's magnetic field. The range is 3.8-16 A/m for scoriaceous micrometeorites and 78-525 A/m for unmelted micrometeorites, which may have preserved a preatmospheric magnetization. The magnetic susceptibility is in the range of 0.005-2.9 SI for cosmic spherules and is in the range of 0.06-0.12 SI for scoriaceous and unmelted micrometeorites. Temperature-dependent susceptibility analyses and thermal demagnetization indicate that magnetite is cation substituted in cosmic spherules. Different populations of magnetite grains may have different degrees of cation substitution within a single micrometeorite. Anisotropy of magnetic susceptibility measurements indicates that micrometeorites are strongly anisotropic (anisotropy degree >15%) and that most have oblate fabrics consistent with the parallel habit of magnetite in barred olivine cosmic spherules.

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Section: Characterization Of Micrometeoritescontrasting

confidence: 51%

Section: Introductionmentioning

confidence: 92%

Magnetic properties of micrometeorites

et al. 2009

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“…These morphologies are consistent with solidification of a melt droplet since their shapes are in agreement with surface tension. The hollow interior of some spherules is recognized amongst spherules from modern collections and suggested to form by contraction on crystallization (Marfaing et al ., ). Some holes are visible suggesting escape structures of an immiscible phase, such as FeNi metal (Figures A, E, and C).…”

Section: Resultsmentioning

confidence: 97%

Cosmic spherules from the Ordovician of Argentina

et al. 2012

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The discovery of magnetic spherules in acid‐insoluble residues from conodont samples encouraged a systematic search for Ordovician micrometeorites from northwestern Argentina. Some 220 melted micrometeorites were recovered from the magnetic fraction of six samples (total rock weight: 23 kg) from the Cordillera Oriental (Santa Rosita Formation) and 17 from five samples (total rock weight: 8.9 kg) from the Argentine Precordillera (Las Aguaditas, Gualcamayo and Las Vacas formations). The specimens resemble I‐type cosmic spherules, in their chemistry and distinct dendritic and polygonal crystalline structures. They represent a flux of micrometeorites several orders of magnitude greater than present. The wide differences in spherule abundance between the Precordillera and the Cordillera Oriental samples could reflect uncertainties in the sedimentary rates or temporal variations in the flux of extraterrestrial matter to Earth. The micrometeorite‐bearing formations span the late Tremadocian to the late Darriliwian (~480–460 Ma), which is consistent with a period of elevated flux of extraterrestrial material, as recorded several thousand kilometres away from coeval horizons in Scotland, Sweden and central China. Copyright © 2012 John Wiley & Sons, Ltd.

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“…Phase separation during melting and then subsequent cooling can cause the formation of nuggets of distinct composition which become detached to leave a cavity (a dimple). A rigid shell develops upon initial cooling, which allows cavities to be retained upon expulsion of nuggets or gases (Marfaing et al 2008).…”

Section: Methodsmentioning

confidence: 99%

A micrometeorite record in Ordovician Durness Group limestones, Isle of Skye

Parnell

Salter

West

2015

Earth and Environmental Science Transactions of the Royal Socie

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Samples of mid-Ordovician Durness Group limestone from Skye yield micrometeorites in the magnetic fraction after dissolution in acid. The micrometeorites are concentrated in the upper part of the sequence, in the Arenig Balnakeil and Croisaphuill formations. This finding is consistent with their stratigraphic distribution determined previously in the Durness district. A single sample of contemporaneous limestones from the Highland Border Fault Zone also yielded a micrometeorite. These observations suggest an elevated flux of meteoritic matter, shortly before the greatest concentration of meteorites in the geological record in the mid-Ordovician of Sweden.

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Study of a set of micrometeorites from Antarctica using magnetic and ESR methods coupled with micro-XRF

Cited by 3 publications

References 26 publications

Magnetic properties of micrometeorites

Magnetic properties of micrometeorites

Cosmic spherules from the Ordovician of Argentina

A micrometeorite record in Ordovician Durness Group limestones, Isle of Skye

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