Though trained as an astronomer, he was a specialist on Greenland. He noticed that ... once all attached in a single landmass he called Pangaea (Greek for "all earth"). They were surrounded ...

During this period, two supercontinents emerged: Rodinia, which formed approximately 1.2 billion years ago and broke apart about 750 million years ago, and Pangaea, which formed around 335 million ...

Though trained as an astronomer, he was a specialist on Greenland. He noticed that ... once all attached in a single landmass he called Pangaea (Greek for "all earth"). They were surrounded ...