Scientists led by the University of Aberdeen have concluded that the great mountain ranges of the world produced by the collision of Earth's tectonic plates reached their great heights thanks to lubricating graphite, which resulted from an abundance of ancient ocean life.
When we look at vast mountain ranges like the Himalayas, the Alps, the Rockies, and the Andes, it's easy to get a sense of the tremendous forces of nature that were able to thrust such great slabs of rock high into the sky over the course of millennia. However, researchers say these forces had a helping hand from dead plankton.
About 2.3 billion years ago, the Earth's environment went through a radical event called the Great Oxygenation. Before this, the Earth's atmosphere was made up almost entirely of nitrogen and carbon dioxide. Then, according to the leading hypothesis, there was an explosion of life in the ancient ocean in the form of cyanobacteria.
For about 500 million years, this bacteria grew and reproduced, converting carbon dioxide into oxygen by means of photosynthesis, reducing the greenhouse effect and setting up the conditions for more advanced life forms to evolve. As these bacteria died, they sank to the seabed and formed large deposits of graphite and other substances.
According to the Aberdeen team, these massive deposits reached their peak about 200 million years before the Earth's crust began to swell and buckle at the points where the oceanic and continental shelf plates met, beginning the formation of the giant mountain ranges we find around the world. As they did so, the team says that the graphite from the bacteria lubricated the breakage of rock into slabs that could be stacked on top of each other to create mountains.
“The geological record for this period includes evidence of an abundance of organic matter in the oceans, which when they died were preserved as graphite in shale," says Professor John Parnell. "While it has long been known that tectonic processes were lubricated, our research shows that it was the sheer abundance of carbon in the ocean that played a crucial role in the crustal thickening that built the Earth’s mountain ranges."
The research was published in Communications Earth & Environment.
Source: University of Aberdeen