Gondwana really was a supercontinent—and it may have helped kickstart life on Earth

This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Some 550 million years ago, Earth looked very different than it does today. The Southern Hemisphere was dominated by an enormous single continent known as Gondwana.

This continent was first recognized by Austrian geologist Eduard Seuss in 1885 based on the presence of a unique plant fossil that was first discovered in the Gondwana Province of India. The fossils were then found in Australia, Africa, Antarctica and South America, demonstrating these landmasses were once connected. But whether Gondwana was an actual "supercontinent" has been a subject of intense scientific debate in recent years.

A new paper I coauthored, published today in Science Advances, helps settle the debate. Our team found a previously hidden part of the Gondwanan landmass that's now buried under mountains, showing it was much bigger than previously thought. The concept of supercontinents and supercontinent cycles emerged in the mid-1980s when geologists first recognized cyclic, global-scale sea-level changes in the geological record.

These cycles date back at least 2 billion years. Since the 1980s, at least four supercontinents have been recognized. The youngest is Pangea, which formed 300–250 million years ago.

Gondwana is the second youngest, at 550–500 million years ago. Rodinia formed about 1 billion years ago, and the oldest verified supercontinent is called Columbia or Nuna, which formed between 2 billion and 1.6 billion years ago. However, Gondwana's supercontinent status has been questioned in the 21st century.

This was because an arbitrary value of 75% of continental landmass was considered necessary to attain supercontinent status, and Gondwana was initially measured at 64%. The initial measurement of Gondwana was based on five core continental fragments: India, South America, Africa, Australia and Antarctica. Subsequent measurements included landmasses extending from the Appalachian Mountains in the United States, through southern Europe, to Turkey, Iran and Pakistan, then connecting to India.