Forces inside Earth helped Antarctica freeze before the Arctic

Topic: Earth Science

Scientists found out why Antarctica became icy millions of years before the Arctic. They discovered that forces deep inside Earth helped raise the land in East Antarctica to high elevations, making it cold enough for ice to form and grow over time.

Scientists have been trying to figure out how Antarctica became covered in ice millions of years ago. The Earth was warmer back then than it is today, so it's surprising that Antarctica developed a massive ice sheet. A team of researchers from the University of Southampton and other institutions found a new explanation for this mystery.

They discovered that the gradual formation of high terrain in East Antarctica helped create elevations cold enough for snow and ice to persist and build up over time. This process began after Antarctica and Africa started separating during the Jurassic Period, 201-143 million years ago. Powerful forces deep inside Earth gradually lifted much of East Antarctica over more than 100 million years.

The researchers used computational models to reconstruct the evolution of East Antarctica's surface across 100 million years. They found that a phenomenon called 'mantle waves' was responsible for much of the gradual uplift. Mantle waves are slow-moving waves that travel beneath continents after tectonic plates begin to separate.

As these mantle waves passed beneath East Antarctica, they helped raise a vast plateau topped by the Gamburtsev Mountains. The simulations indicate that by about 45 million years ago, large parts of East Antarctica had climbed above the critical elevation required for mountain glaciers to develop and expand. Over time, those glaciers grew together to form the East Antarctic Ice Sheet.

Why It Matters

This discovery helps us understand how our planet's climate has changed over millions of years. It also shows that geological processes can have a big impact on the Earth's climate, even when global temperatures are relatively warm.

Key Facts

• The East Antarctic Ice Sheet is now the largest ice sheet on Earth and contains enough frozen water to raise global sea levels by around 52 meters if it were to melt completely.
• The gradual formation of high terrain in East Antarctica helped create elevations cold enough for snow and ice to persist and build up over time.
• Mantle waves are slow-moving waves that travel beneath continents after tectonic plates begin to separate.
• The process of raising the land in East Antarctica began after Antarctica and Africa started separating during the Jurassic Period, 201-143 million years ago.
• The researchers used computational models to reconstruct the evolution of East Antarctica's surface across 100 million years.

Key Terms

Mantle waves

Slow-moving waves that travel beneath continents after tectonic plates begin to separate.

Implications

This discovery helps us understand how our planet's climate has changed over millions of years. It also shows that geological processes can have a big impact on the Earth's climate, even when global temperatures are relatively warm.