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Earth's interior temperature is about 60 degrees Celsius hotter than previously thought and could explain how tectonic plates move on Earth's surface, research by a 28-year-old United States PhD student has found.
PhD student Emily Sarafian stumbled upon the discovery while researching the melting point of mantle rock — the layer between Earth's crust and its core.
"While we did not necessarily set out to measure the mantle temperature, our experimental results on the melting point of mantle rock showed us the new mantle temperature," Ms Sarafian told ABC News.
"In fact, mantle must be 60 degrees Celsius hotter than current estimates. That's a very significant jump."
She said the hotter the mantle is, the softer it would be and the easier it would flow.
"This could explain how tectonic plates are able to move on Earth's surface," Ms Sarafian said.
As scientists are not able to directly take the mantle's temperature, its conditions are simulated in the laboratory by taking synthetic rock to high pressures and temperatures, said Ms Sarafian, who is in a joint Massachusetts Institute of Technology (MIT)-Woods Hole Oceanographic Institution (WHOI) program in collaboration with the Carnegie Institution for Science.
Previous experiments estimating the temperature encountered the problem of water in their synthetic rock from the atmosphere, which causes it to melt it at a lower temperature and made a rock's melting point appear lower than it actually is.
Ms Sarafian said she constructed her experiment the same as researchers before her, but added grains of olivine — which naturally occurs in the mantle — to the synthetic rock.
"During the experiment, the olivine grains would reach equilibrium with the synthetic rock, then after the experiment, we could measure the water content of the olivine grains using Secondary Ion Mass Spectrometry (SIMS) and calculate how much total water was in our experiment," she said.
"This way, we could correct for the water content of our experiments and get an accurate model of the dry mantle solidus."
Earth's interior temperature "affects everything from the movement of tectonic plates to the formation of the planet", WHOI said in a statement.
The new findings could change scientists' understanding of many Earth science issues, including how ocean basins are formed, it said.
University of Melbourne Professor Louis Moresi said it could help researchers create more accurate models to understand the past.
"The thing we can't do by observation is go back into the past. To do that we have to do modelling and simulate the past," Professor Moresi said.
"We're always trying to work out how the ancient geology got to be the way it is now and we have to use models to work out how to reverse what we see today. Every little piece of information helps going into the models."
He said the new information could be used to model and understand what Earth's interior was like 500 million years ago.
Topics: earth-sciences, offbeat, research, science-and-technology, united-states