Asteroid impact could have stirred the ocean

Model offers one explanation for sudden change in deep-ocean chemistry almost 2 billion years ago

The collision of a large extraterrestrial object with Earth almost 2 billion years ago may have stirred the seas worldwide and delivered a small but crucial serving of oxygen to the deep ocean.

The Sudbury impact, named after the Canadian city located near the center of what remains of the ancient crater, happened around 1.85