Also, the bulk composition of the Earth is chondritic; that is, similar to a class of meteorites called chondrites. Chondrites contain several forms of carbon, including diamonds older than our sun.
Because the early Earth was bombarded by meteorites, he says, it is reasonable to conclude that the carbon in diamonds on the Earth is primordial.
Scientists have shown that most diamonds are brought from the Earths interior to its surface by volcanoes. But the volcanoes that bring forth these precious stones are much younger than the diamonds themselves, according to Haggerty.
This combination of old diamonds and young volcanoes indicates that the diamonds were already formed when magma brought them to the surface, said Haggerty.
Additionally, there were two geologically short time periods during which hundreds of diamond-producing volcanoes erupted all over the Earth. One group erupted about one billion years ago, and the other 100 million years ago.
Haggerty suggests that the eruptions were the result of the blooming of molten plumes from the Earths core. The volcanoes occurred randomly around the planet, rather than along continental plate boundaries, lending support to the model of deep primary carbon.
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