Tectonic plates act as variable thermostat

LOS ANGELES, Aug. 16 (UPI) -- U.S. geologists have determined heat loss from the Earth's interior depends on the size and number of tectonic plates above the heated area.

However, the study by University of Southern California, Johns Hopkins University and University of Michigan researchers showed the current Earth system of tectonic plates presents a much improved "blanket" compared with that of 60 million years ago when it consisted of smaller plates that allowed a much higher rate of heat loss.

The study's lead author, University of Southern California Assistant Professor Thorsten Becker, and colleagues found heat flow from the mantle during the last 60 million years was greater than previously estimated.

But the new study, as did previous estimates of heat flow, raises a question: If heat loss for the past few billion years was comparable to estimates, the mantle would have had to be impossibly hot at the beginning of Earth’s history.

The study, which included University of Southern California Associate Professor Frank Corsetti, graduate student Sean Lloyd, Johns Hopkins researcher Clint Conrad and University of Michigan scientist Carolina Lithgow-Bertelloni, is available in the early online issue of the Proceedings of the National Academy of Sciences.