Life › The age of dinosaurs › Pangaea supercontinent
Pangaea breaks apart
from c. 200 million years ago· Event· Earth, climate & extinctions
Well establishedStrong fossil, genetic or geological evidence.
The rifting of Pangaea that opened the Atlantic and Indian Oceans and moved the continents toward today's positions.
See it on the Life map →What happened
Around 200 million years ago, rifts opened between North America and Africa, releasing the CAMP lavas and starting the central Atlantic. Through the Jurassic and Cretaceous, Pangaea split into Laurasia in the north and Gondwana in the south; Gondwana then broke into South America, Africa, India, Antarctica and Australia. The South Atlantic opened from about 130 million years ago, and India drifted north to hit Asia about 50 million years ago. The Atlantic still widens a few centimeters a year.
Why it matters
It separated land animals into isolated populations that evolved differently on each continent, explaining much of today's map of life, such as Australia's marsupials.
The evidence (fossils, genes, rocks)
Matching coastlines, rocks and fossils across oceans; magnetic stripes and ages of the seafloor, oldest about 180 million years in the Atlantic; GPS measurements of plate motion today.
Still debated
What started the rifting, mantle plumes rising from below or forces pulling plates apart, is still debated.
Connections (3)
▸Pangaea supercontinent ended with Pangaea breaks apartWell established
The connection
Supercontinents tend not to last. One idea is that heat built up beneath the huge landmass while stresses grew along its edges, weakening it until rifts opened around 200 million years ago. Over the next 150 million years the pieces drifted apart into today's continents.
When and how
Rifting began between North America and northwest Africa about 200 million years ago and continued through the Jurassic and Cretaceous.
The evidence
Matching rocks and fossils across the Atlantic, magnetic stripes on the seafloor, and ocean crust that grows older away from mid-ocean ridges.
Debates and open questions
Why it broke when and where it did is debated: mantle plumes, trapped heat or plate forces. Earlier supercontinents also formed and split.
▸Pangaea breaks apart unleashed eruptions that caused End-Triassic extinctionStrong evidence
The connection
As Pangaea began to split along what became the central Atlantic, enormous volumes of magma erupted: the Central Atlantic Magmatic Province. Its carbon dioxide and sulfur gases caused sharp warming, brief cooling pulses and ocean acidification, which drove the extinction.
When and how
Along the rift between eastern North America, northwest Africa, Iberia and northern South America, about 201 million years ago; the lavas now lie on four continents.
How sure are we?
Uranium-lead dates show the earliest lavas coinciding with the extinction, and carbon isotopes and fossil leaf pores record a carbon dioxide spike.
Debates and open questions
Whether the rifting set off the eruptions or a deep mantle plume drove both is debated, as is the relative role of carbon dioxide and sulfur.
▸Pangaea breaks apart set India drifting toward India hits Asia: the Himalayas riseStrong evidence
The connection
As Pangaea's southern half, Gondwana, broke up, India split from Africa, then from Madagascar about 88 million years ago, and raced north across the Tethys Ocean. The seafloor ahead of it sank beneath Asia until, around 50 million years ago, India's buoyant continental crust arrived and began crumpling into the Himalayas.
When and how
Across the vanished Tethys Ocean, between Gondwana's breakup (from about 180 million years ago) and India's collision with Asia, about 50 million years ago.
How sure are we?
Rock magnetism records India's changing latitude, seafloor magnetic stripes chart its path, and matching rocks and fossils link India to Madagascar and Antarctica.
Debates and open questions
Why India moved so fast, up to about 15–20 centimeters a year, is debated: a push from a mantle plume, or a pull from two sinking plate edges.