Mountain growth spurts may have sparked complex life on Earth

Researchers studied metamorphic rocks to discover that two distinct periods of mountain growth over the last 3 billion years correlate with the rise of biological diversity on Earth.

The study, published in Science Advances, suggests that these mountain growth spurts provided essential nutrients like phosphorus to the oceans. Before 3 billion years ago, these elements remained trapped in the Earth's crust, leaving the oceans nutrient-starved.

As tectonic plates collided and pushed mountains higher, weathering and erosion released these nutrients into the biosphere. This process allowed photosynthesis to increase atmospheric oxygen levels. The first growth spurt occurred before 2.2 billion years ago, when mountains rose from near sea level to about half the height of the modern Himalayas. The second major spurt happened around 700 million years ago, coinciding with a second major oxidation event.

These changes were linked to the cooling of the planet, which allowed the crust in mountain belts to reach much greater thicknesses. Researchers noted that the maximum thickness of the crust in these belts increased from 30 km to 60 km during the first spurt, and then to nearly 90 km during the second. These massive and irreversible changes in the amount of weathered matter in the oceans may have driven the environmental and biological changes that shaped the planet.

The study suggests that mountains played a much larger role in creating a habitable planet than scientists previously assumed.