Neoarchean

The Neoarchean (/ˌniːoʊ.ɑːrˈkiːən/ NEE-oh-ar-KEE-ən; also spelled Neoarchaean) is the last geologic era in the Archean Eon. It took place from 2800 to 2500 million years ago. We know this time by measuring time, not by looking at rock layers on Earth.

During the Neoarchean, big changes helped shape our planet. Scientists think this is when the first complex life began. These early organisms were very different from simple bacteria. This was a big step in how life changed over time.

This era was also when continents started to come together to form larger landmasses. The way the land moved helped create the bases for the continents we know today.

Complex life

This time saw oxygen appear in the air after oxygenic photosynthesis developed in cyanobacteria. The changes in Earth's environment helped tiny life forms grow and change. New land areas and moving plates let these tiny organisms live in many places.

The earliest signs of very simple life that might be related to complex life we know today come from South Africa. But scientists are still not sure about these findings.

Continental formation

During the Neoarchean era, about 2.7 billion years ago, a supercontinent called Kenorland may have formed. Scientists study Kenorland because it might have held important minerals like volcanic-hosted massive sulphide, gold, and uranium, especially in the Canadian Shield. But some studies say Kenorland might not be the right name. Other supercontinents like Superia or Vaalbara may have existed instead. Some parts once thought to be Kenorland, such as the Churchill Province, may have formed later, around 1.9 billion years ago, in a different time called the Nuna era.

The way supercontinents form and break apart is called the supercontinent cycle. This cycle helps us learn how Earth’s crust changed over time since the time of Pangaea. The movement of Earth’s plates, or plate tectonics, created forces that changed the continents. Processes like metamorphism and magmatic activity helped shape what we see on Earth’s surface today.