Possibility that asteroids colliding with the earth about 3.26 billion years ago triggered continental movement
ByNASA's Marshall Space Flight Center
America'sStanford UniversityDonald Lowe and Norman Sleep, researchers of South AfricaBarberton Green Lava ZoneI found out a small spherical stone as I was conducting an investigation. Analyzing spherical stones, two studies have shown that it is a piece of asteroid that collided with Earth about 3.26 billion years ago and that it may have been a catalyst for moving the Earth's continent I have announced.
Physics of crustal fracturing and chert dike formation triggered by asteroid impact, ~ 3.26 Ga, Barberton greenstone belt, South Africa - Sleep - 2014 - Geochemistry, Geophysics, Geosystems - Wiley Online Library
Massive asteroid may have kickstarted the movement of continents
According to the results of analyzing stones discovered by the two people, the size of an asteroid colliding with the Earth is at least 37 km in diameter, about 4 times the size of an asteroid that is said to have dinosaurs extinct, It crashed into the crater and left a crater of 500 km in width on the ground. Due to the impact of this asteroid crash, there seems to have occurred an earthquake of magnitude 10.8 magnitude that is about 100 times the 2011 East Japan great earthquake. "The temperature of the Earth's atmosphere was rising at a stroke as the asteroid crashed, and the water temperature rose until the upper layer of the sea surface boiled," the two members said in the study.
ByRob de Vries
Simon Redfern of the University of Cambridge said about the reason why the two came to discover small pieces of asteroids "Barbert green lava zone constitutes a continent, an archipelago, etc.CrustIt is said to be about 488.3 million years ago from about 542 million years agoCambrian agePreviously stabilizedKrathonIt is located on the crust called. Kraton is the oldest and stable crust. When the asteroid fell, the Barbert green lava zone was on the seabed where the volcanic activity was active. And it is thought that fragments which asteroid flew into the atmosphere as they flew down were cooled in the air, reached the barbert green lava zone and sunk to the bottom of the ocean. After that, the pieces were influenced by the volcanic activity of the ocean floor, and it solidified so as not to move from the falling place ".
Many huge asteroids are said to collide with the moon from 4.1 billion years ago to 3.8 billion years agoLate heavy bombing periodIt is believed that asteroids collided with the Earth, but most of them have not been found due to crustal deformation.
Lowe and Sleep say "I could not identify the exact place where an asteroid is supposed to collide," Lowe said in the research, "How the Earth changed shape due to the power of the asteroid" It is focused on the point that the asteroid's crash position is not very important.
As one of the influences that the asteroid discovered this time was given to the earth, the two cite the movement of the continent of the earth. There is a thin crust above the mantle located outside the core of the earth, the crust is composed of plates overlapped. The continent seems to be on this crust. Convection generated by the heat trapped in the mantle pushes up the overlapping plate and moves itPlate tectonics theoryIs called. In other words, as the plate moves, the continent moves little by little, together with the crust at the top.
According to Redfern, "Even if the mantle becomes extremely hot, it seems that some other big factor is necessary to move the crust, the impact generated by the two asteroids moves the crust There is much possibility that it became a big factor. "
in Science, Posted by darkhorse_log