The authors of the new work analyzed samples of oceanic crust from 18 mid-ocean ridges.They
The mid-ocean ridge (MOR) is a mountainsystem on the seafloor formed by plate tectonics. It usually has a depth of about 2,600 m and rises about two kilometers above the deepest part of the underwater basin. This is where the ocean floor is being pushed apart.
It turned out that the process of formation of the new crust was the fastest 15-16 million yearsToday, the rate has dropped by a third – 140 mm per year.
The authors emphasize that they indicate the data inaverage. And in reality, each ridge changes at its own pace and during this time it could grow noticeably or weakly - or even, on the contrary, decrease. Nevertheless, the global slowdown is obvious.
The reasons for this process remainresearchers unknown. The team hypothesized that this is due to delayed subduction, a process in which oceanic lithosphere returns to the Earth's mantle at convergent boundaries.
Over the past million years, part of the mountain ranges,such as the Himalayas and the Andes, has grown markedly. This mass enhances the resistance of the continental plates to the oceanic ones that go under them. Subduction is slowing down, and with it, according to scientists, it is difficult to move apart the oceanic plates, and spreading is slowing down.
Read more:
MIT builds stationary heat engine that outperforms turbines
After ten years of work, scientists questioned the standard model of physics
See what sunrise looks like on Mars