Diamonds are evidence of a cooler ancient Earth • Earth.com

Diamonds are evidence of a cooler ancient Earth

04-01-2019


Diamonds are evidence of a cooler ancient Earth Today’s Video of the Day from the Queensland University of Technology (QUT) describes a new theory that the Earth’s upper mantle was a lot cooler 2.5 billion years ago than previously thought.

The researchers studied thousands of volcanic rocks from around the world to analyze their magnesium oxide levels.

While scientists have traditionally believed that the Earth’s mantle was much hotter up until 2.5 billion years ago, the results of the QUT analysis suggest that the upper mantle was no hotter than it is today.

The cool upper mantle theory helps to explain how diamonds formed in the upper mantle, which would have otherwise turned out to be lumps of graphite. Carbon is one of the most important elements on our planet, which led the Geological Society of London to name 2019 the Year of Carbon. Diamonds are a main host for carbon in the deep earth and also have a deeper origin than all other gemstones. Most diamonds are made of carbon recycled over and over again between Earth’s surface and its crust

Earth’s rarest diamonds form from primordial carbon in the mantle The planet’s carbon cycle may not go as deep as scientists have thought Superdeep diamonds, such as the Hope Diamond, are formed in an ancient reservoir of carbon in the lower mantle that is separate from the carbon cycle that operates at Earth’s surface. Therefore in the video above it shows the Diamonds are evidence of a cooler ancient Earth. Colored gemstones tell scientists about the crust; gem diamonds tell scientists about the mantle. This makes diamonds unique among gemstones: Not only do they have great beauty, but they can also help scientists understand carbon processes deep in the earth.

By Chrissy Sexton, Earth.com Staff Writer

Video Credit: Queensland University of Technology


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