Earth's interior is cooling faster than expected

A device is used to determine the thermal conductivity of bridgmanite. The article is titled "Murakami et al, DOI: 10.1016/j.epsl.2021.117329".

The researchers at ETH Zurich have shown in the lab how well a mineral common at the boundary between the Earth's core and mantle conducts heat. They suspect that the Earth's heat may be dissipated sooner than thought.

The story of the cooling of the Earth is that it was covered by a deep ocean of magma 4.5 billion years ago. The planet's surface cooled to form a brittle crust over millions of years. Dynamic processes in motion are set by the enormous thermal energy coming from the Earth's interior.

The questions of how fast the Earth cooled and how long it would take for this cooling to stop are still unanswered.

The boundary between the Earth's core and mantle may be found in the thermal conductivity of the minerals.

The boundary layer is important because it is where the hot iron-nickel melt of the planet's outer core occurs. The temperature between the two layers is very steep, so there is a lot of heat flowing here. The mineral bridgmanite is the main component of the boundary layer. It's very difficult to estimate how much heat this mineral conducts from the Earth's core to the mantle.

Professor Motohiko Murakami and his colleagues from the Carnegie Institute for Science have developed a measuring system that allows them to measure the thermal conductivity of bridgmanite in the laboratory, under the pressure and temperature conditions that prevail inside the Earth. They used a new optical absorption measurement system in a diamond unit to measure it.

The thermal conductivity of bridgmanite is 1.5 times higher than assumed, thanks to the measurement system. The heat flow from the core into the mantle is higher than previously thought. Increased heat flow increases mantle convection and the cooling of the Earth. This may cause plate tectonics to decelerate faster than they were expecting based on previous heat conduction values.

The stable mineral phases at the core-mantle boundary will be changed by rapid cooling of the mantle. Bridgmanite becomes a mineral post-perovskite when it cools. The cooling of the mantle might accelerate even further if post-perovskite appears at the core-mantle boundary.

We could give a new perspective on the evolution of the Earth's dynamics. They think that Earth is cooling and becoming inactive more quickly than expected.

He can't say how long it will take for the currents in the mantle to stop. We don't know enough about these kinds of events to know when they're happening. Understanding how mantle convection works in spatial and temporal terms is the first thing that needs to be done to do that. Scientists need to understand how the decay of radioactive elements in the Earth's interior affects the dynamics of the mantle.

The implications for thermal evolution of the Earth, Earth and Planetary Science Letters was written by Motohiko Murakami. The article is titled "Unanswered questions about the evolution of theepsl."

The Earth and Planetary Science Letters is a journal.

The Earth's interior is cooling faster than expected.

The document is copyrighted. Any fair dealing for the purpose of private study or research cannot be reproduced without written permission. The content is not intended to be used for anything other than information purposes.