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Traces of major collisional events in the asteroid belt in late Eocene marine sediments in Italy

Boschi, Samuele LU ; Schmitz, Birger LU ; Liao, Shiyong ; Xu, Cheng and Li, Weiqiang (2025) In Geology 53(7). p.576-580
Abstract

Based on extraterrestrial chromite grains (63–355 μm) in late Eocene sediments, the Chesapeake Bay impact crater (northeastern United States; 40–85 km diameter) likely formed from an H-chondritic projectile. This impact occurred 10–20 k.y. after the formation of the Popigai crater (Siberia, Russia; ∼100 km). The craters formed at the peak of a 2-m.y. period with a factor of 3–5 enhanced flux of 3He-rich extraterrestrial fine dust to Earth. The Massignano and Monte Vaccaro sections in Italy provide detailed sedimentary records of these events. Previous data from 1168 kg of acid-dissolved limestone at Massignano combined in the present study with 1663 kg of limestone from Monte Vaccaro, spanning the 3He anomaly,... (More)

Based on extraterrestrial chromite grains (63–355 μm) in late Eocene sediments, the Chesapeake Bay impact crater (northeastern United States; 40–85 km diameter) likely formed from an H-chondritic projectile. This impact occurred 10–20 k.y. after the formation of the Popigai crater (Siberia, Russia; ∼100 km). The craters formed at the peak of a 2-m.y. period with a factor of 3–5 enhanced flux of 3He-rich extraterrestrial fine dust to Earth. The Massignano and Monte Vaccaro sections in Italy provide detailed sedimentary records of these events. Previous data from 1168 kg of acid-dissolved limestone at Massignano combined in the present study with 1663 kg of limestone from Monte Vaccaro, spanning the 3He anomaly, reveal a persistent decimeter-thick layer enriched in H-chondritic chromite grains at the stratigraphic level of the Chesapeake Bay impact. These well-preserved grains, free of shock features, likely were released from the regolith of the impactor as it approached Earth. We also report that the small Ir anomaly at the 6.19 m level at Massignano is not reproducible at Monte Vaccaro and may reflect diagenesis or reworking. We revise earlier interpretations and suggest that the late Eocene 3He and chromite anomalies, along with the two large impacts, likely relate to a major breakup event within the Koronis asteroid family, the source of today’s common H chondrites.

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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Geology
volume
53
issue
7
pages
5 pages
publisher
Geological Society of America
external identifiers
  • scopus:105009853424
ISSN
0091-7613
DOI
10.1130/G52994.1
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2025 Geological Society of America. For permission to copy, contact editing@geosociety.org.
id
70b612dc-e77f-4682-956d-776c4883355a
date added to LUP
2026-01-26 13:25:20
date last changed
2026-01-26 13:26:07
@article{70b612dc-e77f-4682-956d-776c4883355a,
  abstract     = {{<p>Based on extraterrestrial chromite grains (63–355 μm) in late Eocene sediments, the Chesapeake Bay impact crater (northeastern United States; 40–85 km diameter) likely formed from an H-chondritic projectile. This impact occurred 10–20 k.y. after the formation of the Popigai crater (Siberia, Russia; ∼100 km). The craters formed at the peak of a 2-m.y. period with a factor of 3–5 enhanced flux of <sup>3</sup>He-rich extraterrestrial fine dust to Earth. The Massignano and Monte Vaccaro sections in Italy provide detailed sedimentary records of these events. Previous data from 1168 kg of acid-dissolved limestone at Massignano combined in the present study with 1663 kg of limestone from Monte Vaccaro, spanning the <sup>3</sup>He anomaly, reveal a persistent decimeter-thick layer enriched in H-chondritic chromite grains at the stratigraphic level of the Chesapeake Bay impact. These well-preserved grains, free of shock features, likely were released from the regolith of the impactor as it approached Earth. We also report that the small Ir anomaly at the 6.19 m level at Massignano is not reproducible at Monte Vaccaro and may reflect diagenesis or reworking. We revise earlier interpretations and suggest that the late Eocene <sup>3</sup>He and chromite anomalies, along with the two large impacts, likely relate to a major breakup event within the Koronis asteroid family, the source of today’s common H chondrites.</p>}},
  author       = {{Boschi, Samuele and Schmitz, Birger and Liao, Shiyong and Xu, Cheng and Li, Weiqiang}},
  issn         = {{0091-7613}},
  language     = {{eng}},
  number       = {{7}},
  pages        = {{576--580}},
  publisher    = {{Geological Society of America}},
  series       = {{Geology}},
  title        = {{Traces of major collisional events in the asteroid belt in late Eocene marine sediments in Italy}},
  url          = {{http://dx.doi.org/10.1130/G52994.1}},
  doi          = {{10.1130/G52994.1}},
  volume       = {{53}},
  year         = {{2025}},
}