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The micrometeorite flux to Earth during the Frasnian–Famennian transition reconstructed in the Coumiac GSSP section, France

Schmitz, Birger LU ; Feist, Raimund; Meier, Matthias M.M. LU ; Martin, Ellinor LU ; Heck, Philipp R.; Lenaz, Davide; Topa, Dan; Busemann, Henner; Maden, Colin and Plant, Amy A., et al. (2019) In Earth and Planetary Science Letters 522. p.234-243
Abstract

We have reconstructed the distribution of extraterrestrial chrome spinels in a marine limestone section across the Frasnian–Famennian stratotype section at Coumiac in southern France, providing the first insights on the types of micrometeorites and meteorites that fell on Earth at this time. The data can test whether the small cluster of roughly coeval, large impact structures is related to an asteroid breakup and shower with possible bearings also on the late Devonian biodiversity crisis. A total of ∼180 extraterrestrial spinel grains (>32 μm) were recovered from 957 kg of rock. Noble-gas measurements of individual grains show high solar-wind content, implying an origin from decomposed micrometeorites. Element analyses indicate a... (More)

We have reconstructed the distribution of extraterrestrial chrome spinels in a marine limestone section across the Frasnian–Famennian stratotype section at Coumiac in southern France, providing the first insights on the types of micrometeorites and meteorites that fell on Earth at this time. The data can test whether the small cluster of roughly coeval, large impact structures is related to an asteroid breakup and shower with possible bearings also on the late Devonian biodiversity crisis. A total of ∼180 extraterrestrial spinel grains (>32 μm) were recovered from 957 kg of rock. Noble-gas measurements of individual grains show high solar-wind content, implying an origin from decomposed micrometeorites. Element analyses indicate a marked dominance of ordinary chondritic over achondritic grains, similar to the recent flux. The relation between H, L and LL meteorites is ∼29–58–13%, similar to the late Silurian flux, ∼31–63–6%, but different from the distribution, ∼45–45–10%, in the recent and the Cretaceous flux. Our data show no indication of a generally enhanced late Devonian micrometeorite flux that would accompany an asteroid shower. However, in a single limestone bed that formed immediately before the Upper Kellwasser horizon, that represents the main end-Frasnian species-turnover event, we found an enrichment of ∼10 ordinary chondritic grains (>63 μm) per 100 kg of rock, compared to the ∼1–3 grains per 100 kg that characterise background. The anomalously abundant grains are of mixed H, L and LL types and may be related to an enhanced flux of extraterrestrial dust during postulated minima in both the 405 ka and 2.4 Ma Earth-orbit eccentricity cycles at the onset of the Upper Kellwasser event. In the present solar system the dust accretion at Earth is the highest at eccentricity minima because of the spatial distribution of dust bands of the zodiacal cloud. Besides this small grain anomaly the data here and in previous studies support a stable meteorite flux through the late Silurian and Devonian, in contrast to the mid-Ordovician, when achondritic meteorites that are rare on Earth today were common, followed by the influx of a flood of debris related to the breakup of the L-chondrite parent body. Our accumulated data for six time windows through the Phanerozoic indicate that the ordinary chondrites make up a major fraction in the meteorite flux since at least the mid-Ordovician. We note that the sources in the asteroid belt of the H and L meteorites, the two most common types of meteorites today and through much of the Phanerozoic, remain elusive.

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keywords
asteroid shower, extraterrestrial chromite, Frasnian–Famennian boundary, meteorite flux
in
Earth and Planetary Science Letters
volume
522
pages
10 pages
publisher
Elsevier
external identifiers
  • scopus:85068961684
ISSN
0012-821X
DOI
10.1016/j.epsl.2019.06.025
language
English
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yes
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19a733df-7d2e-4bc7-8da1-b700aa802c08
date added to LUP
2019-07-22 17:17:19
date last changed
2019-08-28 04:57:12
@article{19a733df-7d2e-4bc7-8da1-b700aa802c08,
  abstract     = {<p>We have reconstructed the distribution of extraterrestrial chrome spinels in a marine limestone section across the Frasnian–Famennian stratotype section at Coumiac in southern France, providing the first insights on the types of micrometeorites and meteorites that fell on Earth at this time. The data can test whether the small cluster of roughly coeval, large impact structures is related to an asteroid breakup and shower with possible bearings also on the late Devonian biodiversity crisis. A total of ∼180 extraterrestrial spinel grains (&gt;32 μm) were recovered from 957 kg of rock. Noble-gas measurements of individual grains show high solar-wind content, implying an origin from decomposed micrometeorites. Element analyses indicate a marked dominance of ordinary chondritic over achondritic grains, similar to the recent flux. The relation between H, L and LL meteorites is ∼29–58–13%, similar to the late Silurian flux, ∼31–63–6%, but different from the distribution, ∼45–45–10%, in the recent and the Cretaceous flux. Our data show no indication of a generally enhanced late Devonian micrometeorite flux that would accompany an asteroid shower. However, in a single limestone bed that formed immediately before the Upper Kellwasser horizon, that represents the main end-Frasnian species-turnover event, we found an enrichment of ∼10 ordinary chondritic grains (&gt;63 μm) per 100 kg of rock, compared to the ∼1–3 grains per 100 kg that characterise background. The anomalously abundant grains are of mixed H, L and LL types and may be related to an enhanced flux of extraterrestrial dust during postulated minima in both the 405 ka and 2.4 Ma Earth-orbit eccentricity cycles at the onset of the Upper Kellwasser event. In the present solar system the dust accretion at Earth is the highest at eccentricity minima because of the spatial distribution of dust bands of the zodiacal cloud. Besides this small grain anomaly the data here and in previous studies support a stable meteorite flux through the late Silurian and Devonian, in contrast to the mid-Ordovician, when achondritic meteorites that are rare on Earth today were common, followed by the influx of a flood of debris related to the breakup of the L-chondrite parent body. Our accumulated data for six time windows through the Phanerozoic indicate that the ordinary chondrites make up a major fraction in the meteorite flux since at least the mid-Ordovician. We note that the sources in the asteroid belt of the H and L meteorites, the two most common types of meteorites today and through much of the Phanerozoic, remain elusive.</p>},
  author       = {Schmitz, Birger and Feist, Raimund and Meier, Matthias M.M. and Martin, Ellinor and Heck, Philipp R. and Lenaz, Davide and Topa, Dan and Busemann, Henner and Maden, Colin and Plant, Amy A. and Terfelt, Fredrik},
  issn         = {0012-821X},
  keyword      = {asteroid shower,extraterrestrial chromite,Frasnian–Famennian boundary,meteorite flux},
  language     = {eng},
  month        = {09},
  pages        = {234--243},
  publisher    = {Elsevier},
  series       = {Earth and Planetary Science Letters},
  title        = {The micrometeorite flux to Earth during the Frasnian–Famennian transition reconstructed in the Coumiac GSSP section, France},
  url          = {http://dx.doi.org/10.1016/j.epsl.2019.06.025},
  volume       = {522},
  year         = {2019},
}