Dating terrestrial impact structures
KW - (U-Th)/He KW - apatite KW - geochronology KW - impact crater KW - Manicouagan KW - zircon UR -
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Meteorites On February 15, 2013 a meteor exploded in the sky over Chelyabinsk, southern Russia.
Although no people or buildings were hit by the resulting meteorite, the shockwave from the exploding object injured about 1500 people and caused damage to 7200 buildings in the region.
The fireball and was caught on video, mainly by dash cameras throughout the region, which were posted on the internet by news organizations individuals.
In cases where high-temperature shock metamorphism of the target materials has occurred without widespread melting, these isotopic chronometers may be partially reset and yield dates that are difficult to interpret unambiguously as the age of impact.Preimpact titanite crystals from a shocked meta-anorthosite sample yield two dates consistent with the impact age, at 212 ± 27 and 214 ± 13 Ma (2s), and two younger dates of 189.6 ± 6.9 and 192.2 ± 9.8 Ma (2s), suggestive of postimpact helium loss. PY - 2011Y1 - 2011N2 - The accurate dating of meteorite impact structures on Earth has proven to be challenging.