Since its formation 4.5 billion years ago, the earth keeps on giving heat, and therefore to cool. This Heat Mainly comes from the radioactive disintegration of the components of various terrestrial envelopes. three other energy sources It may also refer to: Progressive crystallization of the outer core, movements gravitational Minerals crystallization inside the nucleus liquidAnd thisenergy Earth’s internal tides. The assembly produces a significant heat flux which is essential for the generation of Convection Mantellik, here The basis of our planet’s tectonic and volcanic activity is, It can be said that it is the flow of heat that makes the Earth geologically alive. However, this heat flux will not be eternal.

As the Earth cools, it gradually exhausts its internal heat supply. The day will come (far, though) when the heat flux will no longer be enough to support mantle convection. It is quite possible that at that point, Earth will become a “dead” planet, and plate tectonics will end. Although this very long-term development is not in doubt, it is difficult to quantify. because we currently don’t know what exactly Speed The Earth is cooling, or how long it will take for its reserves to be depleted.

Bridgmanite, a more conductive mineral than previously thought

To answer these questions, it is necessary to understand how heat is transmitted inside the Earth, to the surface where it is evacuated by volcanic activity, among other things. One of the key areas appears to be the interface between the outer core and Coat, Indeed, it is at this stage that the liquid crystalline mush of the outer core, composed of a mixture of Doing and of Outin direct contact with the rocks of the mantle. shield There is too much between these two levels and the heat flow is too high. At this interface, the mantle is mainly composed of bridgmanite, So knowing this mineral’s ability to conduct heat would make it possible to better understand the rate of Earth’s cooling. A team of researchers from ETH Zurich and the Carnegie Institution in Washington have thus reproduced the conditions prevailing at the level of the core/mantle interface in the laboratory, in order to measure the radiative thermal conductivity of bridgmanites at the level of the base mantle. inferior.

The results suggest that the average thermal conductivity at the core/mantle interface will be 1.5 times higher than previously estimated. This new value suggests that the heat flux from the core may be greater than previously thought. The recombination of heat flux has two consequences. First, the generated mantle convection must be stronger than the eclipse. As a result, the mantle cools more efficiently, and therefore faster, than predicted by previous designs.

Towards accelerating Earth’s cooling

The results of these new data may be Duration Life of some tectonic activity driven by mantle convection. Rapid cooling of the mantle can lead to modification of mineral phases, particularly at the core/mantle interface. Indeed, when bridgmanite cools, it turns into a new mineral, post-perovskite. However, this mineral conducts heat more efficiently than bridgmanite. Thus, the more the Earth cools, the more post-perovskite will become the dominant mineral at the base of the mantle, accelerating the transfer of heat towards the surface and therefore accelerating cooling.

Study results published in earth and planetary science papers Hence opening up new perspectives on the evolution of Earth’s dynamics. like Mars and mercure, thus the Earth may become inactive much faster than we think. But let’s rest assured, if we still don’t know how long it will take, plate tectonics still has a good life ahead of it.