Telling time with geology

Telling time with geology

Telling time with geology


More than four billion years have passed since the formation of our planet—a stunning amount of time for us to consider. Experts have created units of time termed aeons, eras, periods, and epochs to help with this endeavour.

What is geological Timescale and how is it divided?

  • The division of Earth’s history into discrete periods based on geological occurrences and the emergence or extinction of life forms is known as the geological timescale.
  • Aeons, eras, periods, and epochs are the four main divisions of the geological timescale, listed from largest to smallest.
  • The Archean, Proterozoic, and Phanerozoic aeons are the three main periods of Earth’s history.
  • The Palaeozoic Era, the Mesozoic Era, and the Cenozoic Era are the other divisions of the Phanerozoic Eon.

What are the different types of Geological eras?

  • The Precambrian Era is the oldest and longest geological period, having started roughly 4.6 billion years ago. It spans the period from the creation of Earth to the start of the Phanerozoic Eon. During this time, the earliest life forms, including bacteria and algae, began to appear.
  • From roughly 541 million to 252 million years ago was the Palaeozoic Era. This period is characterized by the quick diversification and complexity of life forms. During this epoch, amphibians, plants, fish, and other creatures first appeared.
  • The Mesozoic Era was a period that lasted from roughly 252 million to 66 million years ago. The Mesozoic Era is frequently referred to as the “Age of Dinosaurs” since they ruled the land during this time. Towards the end of this period, birds and flowering plants also underwent evolutionary 
  • The Cenozoic Era is still in effect today. It started about 66 million years ago. Modern creatures, including mammals and birds, have become more prevalent over this time. At this time, humans were only emerging.

What is Anthropocene?

  • Some scientists contend that the geological timescale needs to include the Anthropocene, a newly suggested geological epoch.
  • Combining the words “anthropo” (meaning “human”) and “cene” (meaning “new”), the term “Anthropocene” expresses the notion that human actions have taken on a major role in influencing the geology and ecosystems of the planet.
  • The Earth’s environment has undergone significant and long-lasting changes as a result of human activity, claims advocates of the Anthropocene.
  • These changes include the transformation of natural landscapes, deforestation, biodiversity loss, pollution, and climate change brought on by greenhouse gas emissions.
  • The issue of establishing a distinct geological marker or “golden spike” that marks the start of the Anthropocene as a new geological epoch is at the center of the argument over its formalization.
  • Radioactive isotopes from nuclear bomb tests, high atmospheric carbon dioxide levels, or a profusion of plastic waste are a few examples of potential indicators under consideration.

Although the Anthropocene has not yet been formally acknowledged in the geological timescale, it has generated important debates about how humans are affecting Earth’s systems and the need for sustainable practices to safeguard the planet’s future.