EARTH × CLIMATE

The Supercontinent Rodinia

~1.1 billion to 700 million years ago

Proterozoic · Mesoproterozoic · Stenian

Rodinia was a supercontinent, a gathering of nearly all the continents around what is now North America, which assembled between 1.3 and 0.9 billion years ago and broke apart in stages from about 800 million years ago.

Rodinia was the supercontinent formed when nearly all the continental masses of the time gathered around what is today North America. It broke apart in stages under the action of mantle plumes. A mantle plume is a column of hot rock that rises from the deep mantle, the thick layer of rock beneath the crust, and thins and fractures the rigid shell of the Earth above it. The break-up has a climatic consequence. It exposes fresh rock and multiplies coastlines in the tropics, where rainfall is heaviest. Both effects accelerate silicate weathering, the chemical attack of silicate rocks by rainwater, which removes carbon dioxide from the atmosphere.

Why it matters

The weathering of tropical rock consumes carbon dioxide, and less carbon dioxide in the air leaves a colder planet. This cooling is one of the reasons researchers regularly invoke the break-up of Rodinia to explain the two most severe glaciations the Earth has known, which followed it.

Dating & uncertainty

Reconstructions rest on palaeomagnetic poles, positions of the magnetic pole recorded in ancient rocks. These poles are still sparse for most cratons, the old stable cores of continents, so the arrangement of continents within Rodinia varies between models. Assembly is placed between 1.3 and 0.9 billion years ago, break-up from about 800 million years ago, and the final separations continue to around 600 million years ago.

Earth history as one day

18:11:065 h 49 min before midnight

if Earth’s 4.54 billion years were compressed into a single day