Twists and turns on the Earth’s surface in Turkey’s Central Anatolian Plateau are a smokescreen for a newly discovered class of plate tectonics. Beneath a depression called the Konya Basin, the earth’s crust is slowly seeping deeper into the planet’s interior; This process gradually shapes the surface geology of not only the basin but also the surrounding plateau.

This is called lithospheric depression; This phenomenon was recently discovered on Earth, and geologists are still trying to figure out the various ways it occurs.

“When we looked at satellite data, we noticed a circular structure in the Konya Basin where the crust is subducting, or the basin is deepening,” says geophysicist Julia Andersen of the University of Toronto.

“This led us to look at other geophysical data below the surface, where we saw seismic anomalies and a thickened crust in the upper mantle, indicating the presence of high-density material there and indicating possible dripping of mantle lithosphere.”

We have a pretty good idea of ​​how it works. When the lower part of the Earth’s crust heats up to a certain temperature, it starts to get a little sticky. Then, like honey or syrup, it slowly flows downwards; It’s a bit like a resin drip experiment, but much bigger and slower.

When this drop descends, it drags the planetary crust with it. This creates a depression or basin. Then, as the droplet leaves the mantle, it swells upward due to the surface spreading effect and returns.

We are just beginning to understand this process, but modeling its evolution allowed Andersen and colleagues to identify a region where dripping into the mantle occurs, in the Arizarro Basin beneath the central Andes. Now careful analysis of surface geology and laboratory experiments led them to another muddy blob beneath the Central Anatolian Plateau, and the signpost became the Konya Basin.

It is known that the Central Anatolian Plateau rose over time. Previous studies had shown that a fragile droplet had gained about a kilometer (0.6 miles) in height over the past 10 million years, thanks to its outflow.

But there is the Konya Basin, which is subsiding at a rate of about 20 millimeters (0.8 inches) per year. That doesn’t seem like much, but an area of ​​subsiding land in a rising region warrants further investigation. The team’s findings suggest that the broader plateau region is in the rebound phase of the lithospheric drop process after dumping its sticky molten load into the mantle. Konya’s pool? This is a second, smaller dropper.

“As the lithosphere thickened and dripped beneath the region, it formed a basin at the surface, which then formed as the underlying weight broke and sank deep into the mantle,” says Russell Pysklyvec, an earth scientist at the University of Toronto.

“We now see that this process was not a one-off tectonic event, and that the initial eruption appears to have spawned subsequent sister events elsewhere in the region, leading to the interestingly rapid collapse of the Konya Basin within the ever-rising Plateau of Turkey.”

The researchers tested this model by setting up a laboratory experiment. They filled a Plexiglas tank with a high-viscosity silicone polymer called polydimethylsiloxane to replace Earth’s sticky lower mantle. A mixture of polydimethylsiloxane and modeling clay was used to replicate the upper mantle, while a mixture of ceramic spheres and silica sand was used as the shell.

They then placed a dense “seed” in the upper mantle to initiate the droplet and observed the results. Within 10 hours the first drop began to fall. By the time it reached the bottom of the box approximately 50 hours later, the secondary emitter had begun to descend. Not a single droplet was associated with horizontal deformation of the surface – only vertical. And these deformations were compatible with the Konya Basin.

“We observed that although there was no horizontal movement of the crust at the surface, over time this secondary drop pulled the crust down and began to form a basin,” says Andersen. “The findings suggest that these major tectonic events are interconnected and that a single lithospheric drop could potentially trigger a cascade of subsequent activity deep within the planet.”

These results suggest that lithospheric subduction is a multistage process and clearly explain the strange, simultaneous uplift and subsidence observed in the Central Anatolian Plateau. The study was published on: Nature Communication.