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DOI	10.1073/pnas.2020977118
	Asteroid break-ups and meteorite delivery to Earth the past 500 million years
	Terfelt F.; Schmitz B.
发表日期	2021
ISSN	0027-8424
卷号	118 期号:24
英文摘要	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. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Asteroid break-up; Chrome spinel; Meteorite delivery; Phanerozoic history
语种	英语
scopus关键词	article; astronomy; grain; Ordovician; sediment
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/238893
作者单位	Astrogeobiology Laboratory, Department of Physics, Lund University, Lund, 221 00, Sweden; Robert A. Pritzker Center for Meteoritics and Polar Studies, Negaunee Integrative Research Center, Field Museum of Natural History, Chicago, IL 60605, United States
推荐引用方式 GB/T 7714	Terfelt F.,Schmitz B.. Asteroid break-ups and meteorite delivery to Earth the past 500 million years[J],2021,118(24).
APA	Terfelt F.,&Schmitz B..(2021).Asteroid break-ups and meteorite delivery to Earth the past 500 million years.Proceedings of the National Academy of Sciences of the United States of America,118(24).
MLA	Terfelt F.,et al."Asteroid break-ups and meteorite delivery to Earth the past 500 million years".Proceedings of the National Academy of Sciences of the United States of America 118.24(2021).