How Ancient Glaciers Transformed Earth’s Landscape and Laid the Foundation for Complex Life, According to Scientists | CNN

More than 500 million years ago, Earth was an icy world. Glaciers were massive and covered much of the land. As they moved, they scratched the ground, dragging minerals with them. When these glaciers melted, they released these materials into the oceans, and scientists believe this event played a crucial role in the development of complex life.

This time period is called the Neoproterozoic Era or “Snowball Earth.” It lasted from about 1 billion to 543 million years ago, seeing landmasses come together into a giant supercontinent known as Rodinia before they separated again. During this time, basic life forms like microbes and sponges thrived in the oceans. After this deep freeze, more complex life began to emerge, with organisms featuring shells and armor.

Scientists believe that this surge of life was linked to the rise of oxygen levels both in the atmosphere and in the oceans. Recent research in the journal Geology now suggests that the movement of ancient glaciers directly affected ocean chemistry, paving the way for the evolution of more complex organisms.

The Neoproterozoic era provides important insights into our planet’s history and our current challenges with climate change. Dr. Chris Kirkland, the lead author of the study, explained how changes in one part of Earth can influence other areas. Today’s rapid climate change is happening much faster than the gradual shifts of ancient times.

Glaciers are known to transport sediments into oceans, lakes, and rivers. However, until now, scientists weren’t sure if the glaciers from the Neoproterozoic actually moved or how they might have eroded the land beneath them. Dr. Kirkland and his team studied ancient rock formations in Scotland and Northern Ireland, looking specifically at zircons, durable minerals that can survive extreme geological changes. By analyzing these zircons, they could learn about ancient Earth.

Their findings showed that the minerals deposited by glaciers during the Snowball Earth period were quite different from those created later in a warmer climate. The researchers noted distinctive patterns in mineral groups that revealed significant changes in sediment composition over time.

Other experts in geology, like Dr. Graham Shields from University College London, acknowledged the study’s findings. While they note that the relationship between glacial movements and the evolution of complex life is a complex one, the data introduced suggest that glaciers did move and actively shape the environment.

Evidence also pointed to significant changes in ocean chemistry as glaciers melted, leading to increased nutrient flow into the ocean, thereby promoting the development of more diverse marine life.

The research indicates that major glaciation events occurred at least twice between 720 million and 635 million years ago. As the ice began to melt, Earth saw important shifts in both ocean and atmospheric chemistry, ultimately increasing levels of oxygen. This rise in oxygen levels may have played a key role in supporting the evolution of early animal life.

Although the idea that glacial debris contributed to early animal evolution isn’t new, questions linger about whether the minerals were sufficient for long-term environmental changes. Dr. Andrew Knoll, a professor at Harvard University, points out that while these findings add valuable insights, the discussion is still ongoing regarding the extent of glaciation’s impact on life creation.

Understanding these ancient processes also sheds light on how modern climate change unfolds. The relationship between CO2 levels, feedback loops, and climatic tipping points remains crucial. As we face unprecedented warming today, studying how past transformations influenced life on Earth can help frame our understanding of current challenges.

“Everything is interconnected,” Dr. Kirkland said. “Change one part of the system, and other parts will change too.”