Why Is It Important to Look at Archean Earth?

Knowledge of Early Earth

• Archean Earth represents a time period near the beginning of the planet. It is the second era behind only the Hadean Era, which covers the time from the formation of Earth until the Archean Era. Looking at this early time increases the knowledge of the formation of life, oceans, land and how present day Earth came into being.

Formation of Land Masses

• The beginning of the Archean Era marks the cooling of the Earth and the formation of oceans as water vapor condensed. Volcanic eruptions continued and eventually formed islands. These small island chains marked the beginning of land masses. The study of how volcanoes produced islands is an important part of Archean history and provides evidence as to the formation of present day islands.

Evidence of Earliest Life

• Determination of the earliest life forms on Earth depends upon examination of the records from the Archean Era. Those records exist in rocks known as cratons. Scientists have found cratons scattered throughout the world, including a large one in North America just north of Michigan. Cratons represent the beginnings of the continents and what scientists call the "core."

Ancient Fossil Records

• The oldest fossils known to exist on Earth date back 3.5 billion years. Known as bacteria microfossils, they represent sedimentary rock called stromatolites. Found in Australia, they consist of mats of blue-green algae in layers. Modern day stromatolites exist in Australia with the same characteristics as the ancient fossils. The fossils that date between 2.7 billion and 3.5 billion years old create some controversy as scientific evidence is not clear as to whether or not they represent organic life. The evidence is clear that fossils from the end of the Archean Era do contain organic fossils that indicate life.