ISUA SUPRACRUSTAL BELT

Partly concealed by the Inland Ice, the rocks of the Isua Supracrustal Belt near Greenland’s capital, Nuuk, are a mirror reflecting some of the most ancient stories of our Earth. Preserved in this 3.8 billion year old rock formation are stunning, multi-coloured rocks called banded iron formations. Their layers reveal the delicate dance between the earliest life and a changing atmosphere, both slowly creeping towards the oxygen-rich and biologically diverse planet we now enjoy, aeons later. Blood red layers are formed of iron rusted by oxygen produced in a frantic proliferation of ocean bacteria, grasping at evolution. However, in Earth’s hostile early atmosphere, time and time again these blooms ran out of the iron armour they required to stop poisoning themselves with the oxygen they produced, resulting in the ivory-white dead layers comprising only quartz. Isua elegantly reveals the baby steps towards oxygen-tolerant bacteria and finally, innumerable lifetimes later, oxygen-loving organisms such as ourselves.