The tectonic plates, these gigantic pieces of crust which float slowly on the terrestrial mantle, play a decisive role in the formation of continents and volcanoes, as well as cratonic thinning under North America. A very recent study, published in the newspaper Geologyadvance the astonishing hypothesis that these plates could contaminate each other and thus cause important phenomena. This discovery may well change the way we see the movements of the plates on our planet.
A new vision on subductions
The subduction zones – where an ocean plaque slides under another – are at the heart of this innovative research, just like the hot spot of Kerguelen which derived under the Indian Ocean. These regions, known to produce the most violent earthquakes and terrifying tsunamis, may well see the phenomenon of subduction spread from one plate to another as a contagion.
Researchers have particularly looked at the Pacific fire beltthis set of volcanoes which surrounds the Pacific Ocean and which is distinguished by an intense tectonic activity. In this region, spectacular events took place several hundred thousand years ago. For example, there is 300 million yearsChina was only a archipelago separated by the vast Asian oceans and Thétys. The subduction movements ended up closing these oceans, thus forming the current Asian continent, a process similar to the formation of a supercontinent and lifting the mountains on the Eurasian plate.
Geochemical traces that maintain the idea of ​​a tectonic infection
The idea of ​​an “infection” between plates also seems to be supported by recent geochemical discoveries. Traces of the old Thétys ocean were found in rocks west of the Pacific. This exchange of materials between different subduction zones has left a particular mark, called anomaly Depal. Mark Allen explains precisely by saying: “It’s like finding someone’s digital imprint on a crime scene”.
There is 260 million yearsa series of subductions in the peaceful plate launched a process which prompted it to sink towards the west under the Asian continent. João Duarte describes this phenomenon by saying: “By disappearing, these oceans may have contaminated the peaceful plate, which then began to subduct to the west under the Asian continent”.
Prospects for the future of tectonic activity
These new observations also open up interesting avenues on the evolution of tectonic activities on a global scale, similar to those observed in the East-African Rift. Even if, nowadays, earthquakes are rare in the Atlantic zone, a significant event Рlike the one that rocked Lisbon in 1755 Рcould well be the precursor sign of a beginning of subduction in this region. Jọo Duarte argues that Iberia and the Caribbean are perhaps in the beginnings of a phenomenon similar to that observed in the Pacific.
According to him, in 100 million yearsit may well be that a new belt of fire is developing around the Atlantic Ocean, like that surrounding the Pacific today. As he said himself: “In 100 million years, a new Atlantic Fire belt could form, exactly as happened in the Pacific. »»
