Five years ago, a team of researchers dropped 39 seismometers at the bottom of the Atlantic to study seismic activity beneath its earth's crust. Much to the team's surprise, she discovered a strange phenomenon.
Indeed, it does seem that there is more movement of the tectonic plates under the Atlantic Ocean, in any case more than what one would expect. And the results of this study shed new light on the understanding of plate movements in the Earth's depths.
According to the researchers, magma surges take place in the Earth's mantle under the Atlantic. Like huge submarine buttons, the mid-Atlantic ridge is pushed up and out . So basically the Atlantic Ocean is widening .
What is happening under the Atlantic Ocean has amazed researchers
The probes set up in parallel lines over 900,000 km across the submarine ridge under the Atlantic were initially intended to be used for the study of a transition zone in the Earth's mantle, at the limit where meet the rigid lithosphere and the underlying weaker asthenosphere.
And based on the data collected, this transition zone is apparently thinner than expected. Upwelling from the lower mantle was thus observed as well as an abnormal rise in temperature under the mid-ocean ridges.
But unlike the upwelling associated with the formation of volcanic islands, those that take place on the mid-Atlantic ridge do not cause eruptions. This suggests that the phenomenon of convection that takes place throughout the Earth's mantle could also be involved in the movement of the plates resting on it.
It may change our understanding of continental drift
The Mid-Atlantic Ridge is conventionally considered to be a relatively quiet location for plate tectonics. But with these results, one can imagine that an ocean can widen a bit like working a pizza dough from the center outwards.
The rise of the mantle in the Atlantic transition zone is thus potentially explained by the existence of an ascending convection cell , which pushes the plates upwards and then pushes them outwards.
However, it is currently still difficult to fully understand this phenomenon, say the researchers, because even the best data obtained are still unclear. The development of better seismic technology is therefore necessary to fully understand what is happening below.