In March 2016, a research team dropped 39 seismic zones from the western tip of Africa to the underside of the Atlantic Ocean, so that nearby and distant earthquakes could be heard. A year later, they have found a hidden story of how the continents are diverging – not drawn from both sides by sub-territories, as previously believed, but perhaps magma in the center of the ocean Being separated by bulge.
Investigations were conducted in parallel lines extending 600 m across the submarine ridge bisecting the Atlantic. Were part of the device Pi lab And Euro-lab Attempts to better understand the transition zone in the Earth’s mantle, the boundary where the planet’s crust and upper mantle, the rigid lithosphere forming the lanes Underlying, weak asthenosphere. A research team at the University of Southampton and the University of Oxford placed sensors on the ocean floor to collect data. The data he collected spanned about 400 miles across the planet. Team analysis of data is Posted on Today in the journal Nature.
“The transition zone itself was much thinner than we expected,” said a video call, which was by Kate Richt, a seismologist at the University of Southampton and a chief scientist on cruises to accumulate and fix deep-sea sensors. “All that states is that we have material upstream from the lower marshes. It is very hot; In general, we think this does not happen under mid-ocean ridges. “
Rickert said such emergence from the lower earthworms is usually associated with the Hawaiian or Iceland-volcanic islands that are known to be avoided frequently. On the Mid-Atlantic Ridge, however, the material is rising from the lower to the upper mantle, but is not clearly eroding. Simply pressing upward strongly, suggesting to researchers that convection throughout the planet’s gorge may have an important role in the tectonics of the plates that relax it.
“The incredible results shed new light on our understanding of how the Earth’s interior is interwoven with plate tectonics,” said Matthew Agones, a seismologist at the Université deli Studio Roma Tray and lead author of the paper. Southampton’s press release.
Initially, the plan was to better understand the definition and thickness of tectonic plates on the Mid-Atlantic Ridge. Reissert said seismometers and magnetocaloric devices on the seabed were image-forming plates, and the team expected the transition area to be “too boring”.
Conventional wisdom has it that places like the Mid-Atlantic Ridge are relatively quiet when it comes to plate tectonics, and the actual geopolitical theater for the plates was the subduction zone, where two plates converge and one is pushed back down by the other. Is pushed. Those shifts are responsible for the imperceptible creep of continents away from each other. Under the Pacific, tectonic plates are moving rapidly, hence the dramatic “ring of fire” that produces seismic and volcanic activity at the periphery of the ocean. The same cannot be said for the gradual march of the Atlantic plates, which are separated by about 1.6 inches per year.
“Why this work is interesting in understanding plate tectonics, if the material is rising up through the transition zone, means that there is an uplift convecting cell that is pushing on the plates and pushing them out,” Co-author Nikon Mason also a seismologist in a video call at the University of Southampton.
If you consider a pizza dough, it is the difference between making the pie by pulling the edges instead of pushing them in the center. Of course, the difference is pushing on a planetary scale, rather than pushing down on a pak.
Until better seismic techniques are developed, it can be difficult to get more information about what is so deep in the mantra. Today, even the best data reads like a “blurred cat scan”, Harmon said. But under the line — and under the sea — they expect to know about the dynamics elsewhere along the ridge, as well as the situation in the tectonic boundaries under the Pacific.