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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Research Article|
April 11, 2025
Early Publication
Traces of major collisional events in the asteroid belt in late Eocene marine sediments in Italy Available to Purchase
Samuele Boschi;
Samuele Boschi
1
State Key Laboratory of Critical Earth Material Cycling and Mineral Deposits, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China2
Astrogeobiology Laboratory, Lund University, Lund 22100, Sweden3
Archaeology, Environmental Changes and Geo-Chemistry, Vrije Universiteit Brussel, Brussels 1050, Belgium
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Birger Schmitz;
Birger Schmitz
2
Astrogeobiology Laboratory, Lund University, Lund 22100, Sweden4
Key Laboratory of Planetary Sciences, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210023, China
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Shiyong Liao;
Shiyong Liao
4
Key Laboratory of Planetary Sciences, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210023, China5
Chinese Academy of Sciences Center for Excellence in Comparative Planetology, Hefei 230026, China
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Cheng Xu;
Cheng Xu
1
State Key Laboratory of Critical Earth Material Cycling and Mineral Deposits, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China
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Weiqiang Li
Weiqiang Li
1
State Key Laboratory of Critical Earth Material Cycling and Mineral Deposits, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China
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Samuele Boschi
1
State Key Laboratory of Critical Earth Material Cycling and Mineral Deposits, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China2
Astrogeobiology Laboratory, Lund University, Lund 22100, Sweden3
Archaeology, Environmental Changes and Geo-Chemistry, Vrije Universiteit Brussel, Brussels 1050, Belgium
Birger Schmitz
2
Astrogeobiology Laboratory, Lund University, Lund 22100, Sweden4
Key Laboratory of Planetary Sciences, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210023, China
Shiyong Liao
4
Key Laboratory of Planetary Sciences, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210023, China5
Chinese Academy of Sciences Center for Excellence in Comparative Planetology, Hefei 230026, China
Cheng Xu
1
State Key Laboratory of Critical Earth Material Cycling and Mineral Deposits, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China
Weiqiang Li
1
State Key Laboratory of Critical Earth Material Cycling and Mineral Deposits, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China
Publisher: Geological Society of America
Received:
06 Dec 2024
Revision Received:
03 Mar 2025
Accepted:
26 Mar 2025
First Online:
11 Apr 2025
Online ISSN: 1943-2682
Print ISSN: 0091-7613
© 2025 Geological Society of America
Geology (2025)
Article history
Received:
06 Dec 2024
Revision Received:
03 Mar 2025
Accepted:
26 Mar 2025
First Online:
11 Apr 2025
Citation
Samuele Boschi, Birger Schmitz, Shiyong Liao, Cheng Xu, Weiqiang Li; Traces of major collisional events in the asteroid belt in late Eocene marine sediments in Italy. Geology 2025; doi: https://doi.org/10.1130/G52994.1
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