Around 541 million years ago, life and organisms really got going on planet Earth. New research shows how the explosion of life has left behind traces in the mantle.
It shows the interplay between Earth's surface and what lies beneath, as the soil is pushed under the ground through subduction.
kimberlites are rare, diamond-filled volcanic rocks. When they are pushed up to the surface, they tell us what is happening deep in the mantle, and researchers measured the carbon composition in 144 samples taken from 60 locations around the world.
A prevailing view among geologists is that carbon trapped inside diamonds doesn't change much over hundreds of millions of years.
The researchers found a shift in the ratio of carbon isotopes around 250 million years ago, at the time when the Cambrian Explosion folded the mantle.
The researchers write that the observations show that biogeochemical processes at the surface have a profound influence on the deep mantle.
The link between the cycling of carbon close to the surface and deeper underground has been difficult to measure, and it has changed over the billions of years that Earth has been around.
It seems clear that dead creatures trapped in sediment found their way into the mantle through plate tectonics. Their carbon is mixed with other material and eventually reaches the surface through volcanic eruptions.
Further observations of strontium and hafnium confirmed the link. The number of possibilities for how these rock compositions were altered was narrowed down by matching the carbon pattern.
The signature for carbon cannot be explained by other processes such as degassing because the isotopes of strontium and hafnium would not be correlated with those of carbon.
As the effects of the climate crisis continue to be felt, the carbon cycle details are important in terms of being aware of what is happening on our planet.
Carbon is taken from and released back into the atmosphere through the recycling of the plates that make up the surface of the planet, according to new studies.
The scientists know that only a small amount of material gets pushed deep into the mantle through subduction zones, which means that there must have been a direct route to the depths of the mantle.
Giuliani says that the subducted rock material in Earth's mantle is not distributed uniformly.
Earth is a complex system. We want to understand this system in more detail.
Science Advances has published the research.
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