The first signs of life

3 800 million years – 3.8 kilometres

The carbon pockets in Greenland’s Isua rocks may be of ancient biological origin. (Mojzsis et al. / Nature)

Life may allready be present in the oceans. Remains of the cells sedimented on to the ocean floor may have preserved in the oldest sedimentary rocks found from Isua, Greenland. However, the biological origin of these carbon inclusions is still uncertain.