Asteroid break-ups and meteorite delivery to Earth the past 500 million years
(2021) In Proceedings of the National Academy of Sciences of the United States of America 118(24).- Abstract
The meteoritic material falling on Earth is believed to derive from large break-up or cratering events in the asteroid belt. The flux of extraterrestrial material would then vary in accordance with the timing of such asteroid family-forming events. In order to validate this, we investigated marine sediments representing 15 time-windows in the Phanerozoic for content of micrometeoritic relict chrome-spinel grains (>32 μm). We compare these data with the timing of the 15 largest break-up events involving chrome-spinel–bearing asteroids (S- and V-types). Unexpectedly, our Phanerozoic time windows show a stable flux dominated by ordinary chondrites similar to today’s flux. Only in the mid-Ordovician, in connection with the breakup of the... (More)
The meteoritic material falling on Earth is believed to derive from large break-up or cratering events in the asteroid belt. The flux of extraterrestrial material would then vary in accordance with the timing of such asteroid family-forming events. In order to validate this, we investigated marine sediments representing 15 time-windows in the Phanerozoic for content of micrometeoritic relict chrome-spinel grains (>32 μm). We compare these data with the timing of the 15 largest break-up events involving chrome-spinel–bearing asteroids (S- and V-types). Unexpectedly, our Phanerozoic time windows show a stable flux dominated by ordinary chondrites similar to today’s flux. Only in the mid-Ordovician, in connection with the breakup of the L-chondrite parent body, do we observe an anomalous micrometeorite regime with a two to three orders-of-magnitude increase in the flux of L-chondritic chrome-spinel grains to Earth. This corresponds to a one order-of-magnitude excess in the number of impact craters in the mid-Ordovician following the L-chondrite break-up, the only resolvable peak in Phanerozoic cratering rates indicative of an asteroid shower. We argue that meteorites and small (<1-km-sized) asteroids impacting Earth mainly sample a very small region of orbital space in the asteroid belt. This selectiveness has been remarkably stable over the past 500 Ma.
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- author
- Terfelt, Fredrik LU and Schmitz, Birger LU
- organization
- publishing date
- 2021-06-15
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Asteroid break-up, Chrome spinel, Meteorite delivery, Phanerozoic history
- in
- Proceedings of the National Academy of Sciences of the United States of America
- volume
- 118
- issue
- 24
- article number
- e2020977118
- publisher
- National Academy of Sciences
- external identifiers
-
- scopus:85107461634
- pmid:34099566
- ISSN
- 0027-8424
- DOI
- 10.1073/pnas.2020977118
- language
- English
- LU publication?
- yes
- id
- 4259d6af-e3e5-4f8d-990d-51ce609c8a2f
- date added to LUP
- 2021-06-28 10:17:20
- date last changed
- 2025-07-15 13:45:49
@article{4259d6af-e3e5-4f8d-990d-51ce609c8a2f,
abstract = {{<p>The meteoritic material falling on Earth is believed to derive from large break-up or cratering events in the asteroid belt. The flux of extraterrestrial material would then vary in accordance with the timing of such asteroid family-forming events. In order to validate this, we investigated marine sediments representing 15 time-windows in the Phanerozoic for content of micrometeoritic relict chrome-spinel grains (>32 μm). We compare these data with the timing of the 15 largest break-up events involving chrome-spinel–bearing asteroids (S- and V-types). Unexpectedly, our Phanerozoic time windows show a stable flux dominated by ordinary chondrites similar to today’s flux. Only in the mid-Ordovician, in connection with the breakup of the L-chondrite parent body, do we observe an anomalous micrometeorite regime with a two to three orders-of-magnitude increase in the flux of L-chondritic chrome-spinel grains to Earth. This corresponds to a one order-of-magnitude excess in the number of impact craters in the mid-Ordovician following the L-chondrite break-up, the only resolvable peak in Phanerozoic cratering rates indicative of an asteroid shower. We argue that meteorites and small (<1-km-sized) asteroids impacting Earth mainly sample a very small region of orbital space in the asteroid belt. This selectiveness has been remarkably stable over the past 500 Ma.</p>}},
author = {{Terfelt, Fredrik and Schmitz, Birger}},
issn = {{0027-8424}},
keywords = {{Asteroid break-up; Chrome spinel; Meteorite delivery; Phanerozoic history}},
language = {{eng}},
month = {{06}},
number = {{24}},
publisher = {{National Academy of Sciences}},
series = {{Proceedings of the National Academy of Sciences of the United States of America}},
title = {{Asteroid break-ups and meteorite delivery to Earth the past 500 million years}},
url = {{http://dx.doi.org/10.1073/pnas.2020977118}},
doi = {{10.1073/pnas.2020977118}},
volume = {{118}},
year = {{2021}},
}