Stirred not shaken; critical evaluation of a proposed Archean meteorite impact in West Greenland
| Autor: | Aaron J. Cavosie, Chris Yakymchuk, Christopher L. Kirkland, Julie A. Hollis, Pedro Waterton, Laure Martin, Nicholas J. Gardiner, Agnete Steenfelt, Kristoffer Szilas |
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| Přispěvatelé: | University of St Andrews. School of Earth & Environmental Sciences |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
010504 meteorology & atmospheric sciences
Archean Geochemistry North Atlantic Craton zircon 010502 geochemistry & geophysics 01 natural sciences Impact crater Geochemistry and Petrology Earth and Planetary Sciences (miscellaneous) Impact structure 0105 earth and related environmental sciences Maniitsoq GE Biosphere DAS Early Earth planar deformation features Geophysics Meteorite Space and Planetary Science Isotope geochemistry bolide Geochronology impact Geology GE Environmental Sciences |
| Zdroj: | Yakymchuk, C, Kirkland, C L, Cavosie, A J, Szilas, K, Hollis, J, Gardiner, N J, Waterton, P, Steenfelt, A & Martin, L 2021, ' Stirred not shaken; critical evaluation of a proposed Archean meteorite impact in West Greenland ', Earth and Planetary Science Letters, vol. 557, 116730 . https://doi.org/10.1016/j.epsl.2020.116730 |
| DOI: | 10.1016/j.epsl.2020.116730 |
| Popis: | Funding Information: The Ministry of Mineral Resources and Labour, Greenland Government supported field and analytical work. Large meteorite impacts have a profound effect on the Earth's geosphere, atmosphere, hydrosphere and biosphere. It is widely accepted that the early Earth was subject to intense bombardment from 4.5 to 3.8 Ga, yet evidence for subsequent bolide impacts during the Archean Eon (4.0 to 2.5 Ga) is sparse. However, understanding the timing and magnitude of these early events is important, as they may have triggered significant change points to global geochemical cycles. The Maniitsoq region of southern West Greenland has been proposed to record a ∼3.0 Ga meteorite impact, which, if confirmed, would be the oldest and only known impact structure to have survived from the Archean. Such an ancient structure would provide the first insight into the style, setting, and possible environmental effects of impact bombardment continuing into the late Archean. Here, using field mapping, geochronology, isotope geochemistry, and electron backscatter diffraction mapping of 5,587 zircon grains from the Maniitsoq region (rock and fluvial sediment samples), we test the hypothesis that the Maniitsoq structure represents Earth's earliest known impact structure. Our comprehensive survey shows that previously proposed impact-related geological features, ranging from microscopic structures at the mineral scale to macroscopic structures at the terrane scale, as well as the age and geochemistry of the rocks in the Maniitsoq region, can be explained through endogenic (non-impact) processes. Despite the higher impact flux, intact craters from the Archean Eon remain elusive on Earth. Publisher PDF |
| Databáze: | OpenAIRE |
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