University research team makes geological discovery

While searching for one scientific breakthrough, university geology professor Richard Walker and his research team stumbled across another — parts of Earth's mantle remained unchanged through the chaotic period after its formation.

From about 2.8 to 4.5 billion years ago, the Earth was experiencing growing pains. Collections of cosmic dust were bombarding the Earth, and until now, the scientific community widely believed Earth melted, erasing remants of one of early Earth's interior layers — the mantle.

Using a 2.8 billion-year-old rock from Russia, Walker and his team of two researchers proved that this widespread belief was false.

The discovery is important because the findings can help scientists better understand the Earth's complexities — specifically how it formed into what it is today, according to a university press release.

Walker attributes the team's success to the precision of the instruments they used to measure the Tungsten in the rocks, which helps date the rocks for the researchers.

The team disolved the rocks and then removed the Tungsten — an element that can be found in light bulb filaments — from the rocks. A device, called a mass spectrometer, then measures the type of Tungsten in the samples, which Walker said gives his team "a window into the Earth's mantle."

Their findings showed that the rocks, called komatiites, contained material that could have only been present in the early stages of Earth's development. He said this evidence contradicts the old belief that the mantle would have mixed together after being struck by the massive object.

"[It's like] building a model Earth out of clay and adding a piece of green clay and a little bit of red clay, and putting them together, but they would remain separate," Walker said.

While most of the Earth — including parts of the mantle — was undergoing change, this part seemed to stay separate for at least 1.7 billion years. According to the author of the study, Mathieu Touboul, this was most likely the layer between Earth's core and mantle.

The team doesn't know if that portion of the mantle is still separate or why the portion was unmixed. However, they plan to focus their studies on this in the future.

The next step: Looking at more modern rocks, according to Touboul, to see if this part of the mantles is the same today as it was 2.8 billion years ago.

akinnibi@umdbk.com