EARTH

The First Continents

~3.2 to 2.5 billion years ago

Archean · Mesoarchean

Continental crust is rich in silica, which makes it lighter than the rock of the ocean floor, so it rides higher on the mantle. When it grew thick enough, its surface rose above the sea, and this time the land endured: islands had come and gone before, but these blocks were anchored by roots of rigid mantle rock reaching 150 to 250 kilometres down. Geologists call the survivors cratons, and one sits at the heart of every modern continent.

Why it matters

Dry land changes everything that comes after: rain weathers the rock, rivers carry its nutrients to the sea, carbon gets buried, and there is finally somewhere to walk.

Dating & uncertainty

Fragments of land broke the surface as early as 3.8 Ga, but only briefly. Stable, craton-scale land appears between 3.2 and 3.0 Ga, and the modern ratio of land to sea is reached around 2.5 to 2.2 Ga.

Sources

1. Chowdhury et al. (2021), PNAS · Magmatic thickening of crust in non-plate tectonic settings initiated the subaerial rise of Earth's first continents 3.3 to 3.2 billion years ago
2. Pearson et al. (2021), Nature · Deep continental roots and cratons
3. Chowdhury et al. (2025), Annual Review of Earth and Planetary Sciences · Subaerial emergence of continents on Archean Earth

Earth history as one day

07:05:0116 h 55 min before midnight

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