Previous research estimated that it took hundreds of million years for early Earth’s magma ocean to solidify, but new research narrows these large uncertainties down to less than just a couple of million years.
“This magma ocean has been an important part of Earth’s history, and this study helps us answer some fundamental questions about the planet,” said Dr. Mainak Mookherjee, a researcher at Florida State University.
“When magma cools, it forms crystals. Where those crystals end up depends on how viscous the magma is and the relative density of the crystals.”
“Crystals that are denser are likely to sink and thus change the composition of the remaining magma.”
“The rate at which magma solidifies depends on how viscous it is.”
“Less viscous magma will lead to faster cooling, whereas a magma ocean with thicker consistency will take a longer time to cool.”
Like this research, previous studies have used fundamental principles of physics and chemistry to simulate the high pressures and temperatures in the Earth’s deep interior.
Scientists also use experiments to simulate these extreme conditions.
But these experiments are limited to lower pressures, which exist at shallower depths within the Earth.
They don’t fully capture the scenario that existed in the planet’s early history, where the magma ocean extended to depths where pressure is likely to be three times higher than what experiments can reproduce.
To overcome those limitations, Dr. Mookherjee and colleagues ran their simulation for up to six months. This eliminated much of the statistical uncertainties in previous works.
“Earth is a big planet, so at depth, pressure is likely to be very high,” said Dr. Suraj Bajgain, a researcher at Lake Superior State University.
“Even if we know the viscosity of magma at the surface, that doesn’t tell us the viscosity hundreds of km below it. Finding that is very challenging.”
The research also helps explain the chemical diversity…
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