Stirred not shaken; critical evaluation of a proposed Archean meteorite impact in West Greenland
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Stirred not shaken; critical evaluation of a proposed Archean meteorite impact in West Greenland. / Yakymchuk, Chris; Kirkland, Christopher L.; Cavosie, Aaron J.; Szilas, Kristoffer; Hollis, Julie; Gardiner, Nicholas J.; Waterton, Pedro; Steenfelt, Agnete; Martin, Laure.
In: Earth and Planetary Science Letters, Vol. 557, 116730, 03.2021.Research output: Contribution to journal › Journal article › peer-review
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T1 - Stirred not shaken; critical evaluation of a proposed Archean meteorite impact in West Greenland
AU - Yakymchuk, Chris
AU - Kirkland, Christopher L.
AU - Cavosie, Aaron J.
AU - Szilas, Kristoffer
AU - Hollis, Julie
AU - Gardiner, Nicholas J.
AU - Waterton, Pedro
AU - Steenfelt, Agnete
AU - Martin, Laure
PY - 2021/3
Y1 - 2021/3
N2 - 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.
AB - 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.
KW - bolide
KW - impact
KW - Maniitsoq
KW - North Atlantic Craton
KW - planar deformation features
KW - zircon
U2 - 10.1016/j.epsl.2020.116730
DO - 10.1016/j.epsl.2020.116730
M3 - Journal article
VL - 557
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
SN - 0012-821X
M1 - 116730
ER -
ID: 255127491