2023-09-27 06:00:05
The mystery of how the Earth’s 4-billion-year-old crust formed is beginning to unravel, thanks to new discoveries suggesting the existence of plate tectonics from that ancient era. These conclusions revolutionize our understanding of the processes that shaped not only the Earth, but perhaps also other planets in the Solar System (The solar system is a planetary system composed of a star, the…).
Possible methods of formation of the Eoarchean continental crust.
a) Sagduction (the dense crust sinks into the mantle due to gravity),
b) superposition of the continental crust on a boundary of convergent plates where it is less dense than the underlying mantle,
c) shallow subduction at a convergent plate boundary.
This research supports models b and c.
Credit: Alan Hastie et al. 2023 and Allen P. Nutman 2023.
The formation of this continental crust remains enigmatic. Dr. Alan Hastie and his colleagues at the University of Edinburgh conducted fusion experiments. at high pressure-temperature on oceanic plateau basalts. This work indicates that the continental crust might not form at pressures lower than 1.4 GigaPascals (GPa), which suggests an origin linked to convergent subduction zones.
In addition to Earth, traces of silica-rich continental crusts have also been found on Mars and Venus, broadening the implications of these findings to other areas. other planets of the Solar System. The research team also found that certain minerals, such as garnet and rutile …), play a key role in these training processes.
Even more intriguing, scientists suggest that gases released by volcanism, notably carbon monoxide and methane, might have played a role in the appearance of life on Earth. These elements might constitute a source of prebiotic molecules, leading to the emergence of the first microbial organisms.
Areas such as the Isua greenstone belt in Greenland and the Archaean slave craton in Canada are considered the remnants of convergent plate margins above ancient subduction zones. In these regions, metabasic magmas would have mixed fluids from the melting subducting crust to produce new silica-rich magmas.
1695850193
#role #plate #tectonics #appearance #life
