Most text on the National Cancer Institute website may be reproduced or reused freely. The National Cancer Institute should be credited as the source and a link to this page included, e.g., âImmunotherapy: Using the Immune System to Treat Cancer was originally published by the National Cancer Institute.â
Panthalassa, also known as the Panthalassic or Panthalassan Ocean, (from Greek Ïá¾¶Î½ all and Î¸Î¬Î»Î±ÏÏÎ± sea), was the superocean that surrounded the supercontinent Pangaea. During the PaleozoicâMesozoic transition c. 250 Ma it occupied almost 70% of Earth's surface.
asthenosphere-the soft, flexible upper layer of the mantle, on which the tectonic plates move. continental drift-the theory that all of Earth's continents were once joined together into a single large landmass, and then moved apart, forming the continents we see today. convection-transfer of heat by movement of a fluid.ondwana-the southern continent formed when Pangaea split into two pieces. Laurasia-the northern continent formed when Pangaea split into two pieces. lithosphere-the rigid, brittle layer made up of the crust and the uppermost part of the mantle. It is broken up into pieces called tectonic plates.