Panthalassa

ancient ocean

Also known as: Panthalassic Ocean

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

July 1, 2026

Quick Summary

Panthalassa was a vast, global ocean that surrounded the supercontinent of Pangea. This supercontinent, which included nearly all of Earth's landmasses, existed from the Early Permian Epoch (around 299 million years ago) until it began to break apart about 200 million years ago.123

The currents within Panthalassa were likely simple and slow, and the Earth's climate was probably warmer than it is today. As Pangea broke apart, Panthalassa eventually gave rise to the modern oceans, including the Pacific Ocean. The study of ancient oceans like Panthalassa is part of paleoceanography, which examines Earth's oceanographic history through its sedimentary record and tectonic plate movements.41

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

5 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

paleoceanography
…of Pangea, one enormous ocean, Panthalassa, existed on Earth. Currents in this ocean would have been simple and slow, and Earth’s climate was, in all likelihood, warmer than today. The Tethys seaway formed as Pangea broke into Gondwana and Laurasia. In the narrow ocean basins of the central North Atlantic,…
Read More
…of Pangea, one enormous ocean, Panthalassa, existed on Earth. Currents in this ocean would have been simple and slow, and Earth’s climate was, in all likelihood, warmer than today. The Tethys seaway formed as Pangea broke into Gondwana and Laurasia. In the narrow ocean basins of the central North Atlantic,…
Read More

Permian Period
The Permian environment
…and a huge ocean basin, Panthalassa, with its branch, the Tethys Sea (a large indentation in the tropical eastern side of Pangea).
Read More
…and a huge ocean basin, Panthalassa, with its branch, the Tethys Sea (a large indentation in the tropical eastern side of Pangea).
Read More

Triassic Period
Paleogeography
…the globe was covered by Panthalassa, an enormous world ocean that stretched from pole to pole and extended to about twice the width of the present-day Pacific Ocean at the Equator. Scattered across Panthalassa within 30° of the Triassic Equator were islands, seamounts, and volcanic archipelagoes, some associated with deposits
Read More
…the globe was covered by Panthalassa, an enormous world ocean that stretched from pole to pole and extended to about twice the width of the present-day Pacific Ocean at the Equator. Scattered across Panthalassa within 30° of the Triassic Equator were islands, seamounts, and volcanic archipelagoes, some associated with deposits
Read More