Mark A. Garlick
An international team of space scientists has found new evidence of a low-altitude meteorite impact that hit the Antarctic ice sheet 430,000 years ago.
Extraterrestrial particles – condensation spheres – recovered on the summit of Walnumfjellet, in the Sør Rondane Mountains, Queen Maud Land, in eastern Antarctica, indicate an unusual impact, where a jet of melted and vaporized meteorological material, resulting from the atmospheric entry of an asteroid with at least 100 meters, reached the surface at high speed.
This type of explosion caused by a single asteroid impact is described as intermediary, since it is larger than an air explosion, but smaller than an impact crater event.
The extraterrestrial particles examined were found during the 2017-2018 Belgian Antarctic Meteorite (BELAM) expedition based on the Belgian Princess Elisabeth Antarctica Research Station and financed by the Belgian Scientific Policy (Belspo).
O main chondritic volume, a trace element chemistry it’s the high nickel content of the debris demonstrate the extraterrestrial nature of the recovered particles.
Their unique isotopic oxygen markers indicate that they interacted with oxygen derived from the Antarctic ice sheet during its formation in the impact plume.
According to the team led by Matthias van Ginneken, from the Center for Astronomy and Planetary Sciences of the School of Physical Sciences, the results indicate that this was an impact much more dangerous that the events of Tunguska and Chelyabinsk on Russia in 1908 and 2013, respectively.
This investigation is an important discovery for the geological record where the evidence of these events is scarce due to the difficulty in identifying and characterizing the impact particles.
The study also highlights the importance of reevaluating the threat of medium-sized asteroids, since similar events are likely to produce similar particles.
This event would be destructive over a large area, corresponding to the area of interaction between the hot jet and the ground.
“Although events do not threaten human activity if they occur over Antarctica, if they occurred above a densely populated area, they would result in millions of victims e serious damage over distances of up to hundreds of kilometers, ”van Ginneken said in a statement.
This study was published in late March in the scientific journal Science Advances.
Maria Campos, ZAP //
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