The fall, recovery, classification, and initial characterization of the Hamburg, Michigan H4 chondrite

Heck, P. R. et al. (2020) The fall, recovery, classification, and initial characterization of the Hamburg, Michigan H4 chondrite. Meteoritics and Planetary Science, 55(11), pp. 2341-2359. (doi: 10.1111/maps.13584)

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The Hamburg meteorite fell on January 16, 2018, near Hamburg, Michigan, after a fireball event widely observed in the U.S. Midwest and in Ontario, Canada. Several fragments fell onto frozen surfaces of lakes and, thanks to weather radar data, were recovered days after the fall. The studied rock fragments show no or little signs of terrestrial weathering. Here, we present the initial results from an international consortium study to describe the fall, characterize the meteorite, and probe the collision history of Hamburg. About 1 kg of recovered meteorites was initially reported. Petrology, mineral chemistry, trace element and organic chemistry, and O and Cr isotopic compositions are characteristic of H4 chondrites. Cosmic ray exposure ages based on cosmogenic 3He, 21Ne, and 38Ar are ~12 Ma, and roughly agree with each other. Noble gas data as well as the cosmogenic 10Be concentration point to a small 40–60 cm diameter meteoroid. An 40Ar-39Ar age of 4532 ± 24 Ma indicates no major impact event occurring later in its evolutionary history, consistent with data of other H4 chondrites. Microanalyses of phosphates with LA-ICPMS give an average Pb-Pb age of 4549 ± 36 Ma. This is in good agreement with the average SIMS Pb-Pb phosphate age of 4535.3 ± 9.5 Ma and U-Pb Concordia age of 4535 ± 10 Ma. The weighted average age of 4541.6 ± 9.5 Ma reflects the metamorphic phosphate crystallization age after parent body formation in the early solar system.

Item Type:Articles
Additional Information:Part of this work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and was supported by the LLNL-LDRD Program under Project No. 17-ERD-001. LLNL-JRNL-765108. AB acknowledges research funding support from NSERC Discovery Grant (RGPIN/06310-2014) and Canada Research Chair programs. JG acknowledges support from the National Science Foundation Graduate Research Fellowship (DGE-1144082 and DGE-1746045). The authors acknowledge the National Aeronautics and Space Administration for support through the following grants: 80NSSC17K0250 (to AMD); NNX16AD34G (to QZY), 80NSSC18K0854 (to PJ). This project has been made possible in part by grant number 2019-198156 from the Chan Zuckerberg Initiative DAF, an advised fund of Silicon Valley Community Foundation.
Glasgow Author(s) Enlighten ID:Greer, Dr Jennika
Authors: Heck, P. R., Greer, J., Boesenberg, J. S., Bouvier, A., Caffee, M. W., Cassata, W. S., Corrigan, C., Davis, A. M., Davis, D. W., Fries, M., Hankey, M., Jenniskens, P., Schmitt‐Kopplin, P., Sheu, S., Trappitsch, R., Velbel, M., Weller, B., Welten, K., Yin, Q.‐Z., Sanborn, M. E., Ziegler, K., Rowland, D., Verosub, K. L., Zhou, Q., Liu, Y., Tang, G., Li, Q., Li, X., and Zajacz, Z.
College/School:College of Science and Engineering > School of Geographical and Earth Sciences > Earth Sciences
Journal Name:Meteoritics and Planetary Science
ISSN (Online):1945-5100
Copyright Holders:Copyright: ©2020 The Authors
First Published:First published in Meteoritics and Planetary Science 55(11): 2341-2359
Publisher Policy:Reproduced under a Creative Commons licence

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