The Cambium eruption is believed to be the beginning of life appearing on Earth.
REPUBLIKA.CO.ID, JAKARTA — The Cambrian eruption, which occurred about 541 million years ago, is believed by scientists to be the time when life and organisms really flourished on planet Earth. Now new research reveals how that explosion of life has left its mark deep in the Earth’s mantle.
For scientists, these eruptions show the interconnected interactions between the Earth’s surface and what lies beneath it. This is because sediment carrying organic matter is pushed underground over a wide geological time span through subduction interactions.
The new study looks at rare, diamond-filled volcanic rocks called kimberlites. Researchers measured the carbon composition in 144 of these rock samples taken from 60 locations around the world.
The prevailing view among geologists is that the carbon trapped in diamonds does not vary much over a span of hundreds of millions of years. But here the researchers found a shift in the ratio of specific carbon isotopes about 250 million years ago, about when sediment from the Cambrian Explosion would have folded into the mantle.
This is a shift potentially caused by a major change in carbon cycle during times when the biosphere or zone of life increased in mass and diversity.
“These observations suggest that biogeochemical processes at the Earth’s surface have a major influence on the deep mantle, revealing an integral relationship between the deep and shallow carbon cycles,” the researchers wrote. SciencealertThursday (10/3/2022).
This relationship between the carbon cycle close to the surface and deeper underground is not easy to quantify. The carbon cycle has changed significantly over the billions of years the Earth has existed.
It seems clear that dead creatures trapped in sediments found their way into the mantle via plate tectonics. Their carbon remains mixed with other materials before eventually reaching the surface again through events such as volcanic eruptions.
Scientists then observed strontium and hafnium in the samples. They matched the carbon pattern, narrowing the number of possibilities for how the composition of these rocks was altered.
New studies continue to reveal more and more about how carbon is taken up from and released back into the atmosphere, especially through the continuous recycling of the tectonic plates that make up the surfaces of other planets.
“This confirms that the subducted rock material in the mantle of the earth not homogeneously distributed, but moving along certain trajectories,” said Giuliani. “Earth is truly a complex whole system. And we now want to understand this system in more detail,” he said.
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