Below the American west medium, in the continent of North America, the lower part of the earth’s crust is dripping inside planetarium.
There, molten rock drops are merging into the upper mantle of the planet, and finally gain enough mass to precipitate deeper, a slow and gradual mechanism revealed through the seismic monitoring that shows the thinning lithosphere underlying the region.
It’s nothing to worry about. Only recently discoveredThe lithospheric drip also occurs in other parts of the world, but revelation opens a new window to the unique geological processes of our dynamic land.
“This kind of thing is important if we want to understand how a planet has evolved for a long time,” explains the geophysicist Thorsten Becker from the University of Texas in Austin. “It helps us understand how the continents are done, how you break them and how recycles.”
The type of lithosphere here is a Craton – A particularly large and stable section of the land cortex that has existed, relatively unchanged, for a very long period of time. Because they are so stable, it is believed that they are the nuclei around which the continents are formed. We know about Around 35 crratones stalking under our feet.
The lithospheric drip occurs when the lower part of the Earth’s rocky cortex is heated at a certain temperature. As the rock melts, a drop begins to form, and finally becomes heavy enough to break and fall more deeply on the planet. It is a bit like an extreme version of a Tone drop experiment.
In some cases, as in the anatolia plateau of the Andes and Türkiye, this process can create wrinkles on the surface of the planet that betray the activity that occurs below. In this case, however, a team led by Seismologist Junlin Hua, currently he University of Science and Technology of China, but at the University of Texas, while conducting this research, he used seismic data to rebuild the activity at the bottom of the Earth’s crust.
They used a computer model that builds a map of the earth’s cortex from seismic data collected by the Earth drawer Consortium. It is like taking an radiography of the cortex, revealing where it is thicker and thinner, and how its density varies.
“Due to the use of this method completely, we have a better representation of that important area between the deep mantle and the less deep lithosphere where we would expect clues about what is happening with the lithosphere,” Becker explains.
The team’s work reveals that the crraton that is found in most of the American continent is thinning, with the focal point below the west of the United States, and the probable cause is the lithospheric drip.
What is even more intriguing is what is causing it. About 600 kilometers (373 miles) from the Craton, the old cliff tectonic plate slides under the North America tectonic plate, a process known as subduction.
This process has been developed for hundreds of millions of years; At this point, the Farallon plate has It has been almost completely subducedWith most now sitting in the lower mantle, under the American dish. The seismic data suggests that their presence is redirecting the large -scale mantle flows that cut the bottom of the crraton, weakening it.
The drip process could be exacerbated by the previous weakening of the lithosphere; An example of this would be through the release of volatiles of the remains of the Slaballon Slab subductors.
Together, these processes could soften and weaken the lower part of the crraton enough to facilitate the lithospheric dripping, thinning the crraton around which the continent is structured.
Although the focal point is under the west medium, the effects are widespread throughout the Craton, the researchers found. But it is a process that has time scales from millions to billions of years, and it is unlikely that it affects anyone who lived in the American continent for many generations to come.
The investigation has been published in Geoscience of nature.
#Earths #crust #dripping #west
