Zooming In: Visualizing the Relative Size of Particles

The Anthropocene: A New Epoch in the Earth’s History

Over the course of Earth’s history, there have been dramatic shifts in the landscape, climate, and biodiversity of the planet. And it is all archived underground.

Layers of the planet’s crust carry evidence of pivotal moments that changed the face of the Earth, such as the ice age and asteroid hits. And scientists have recently defined the next major epoch using this geological time scale—the Anthropocene.

In this infographic we dig deep into the Earth’s geological timeline to reveal the planet’s shift from one epoch to another, and the specific events that separate them.

Understanding the Geological Timeline

The Earth’s geological history is divided into many distinct units, from eons to ages. The time span of each varies, since they’re dependent on major events like new species introduction, as well as how they fit into their parent units.

Note: Subepochs (between epochs and ages) have also been ratified for use in 2022, but are not yet clearly defined.

If we were to cut a mountain in half, we could notice layers representing these changing spans of time, marked by differences in chemical composition and accumulated sediment.

Some boundaries are so distinct and so widespread in the geologic record that they are known as “golden spikes.” Golden spikes can be climatic, magnetic, biological, or isotopic (chemical).

Earth’s Geological Timeline Leading Up to the Anthropocene

The Earth has gone through many epochs leading up to the modern Anthropocene.

These include epochs like the Early Devonian, which saw the dawn of the first early shell organisms 400 million years ago, and the three Jurassic epochs, which saw dinosaurs become the dominant terrestrial vertebrates.

Over the last 11,700 years, we have been living in the Holocene epoch, a relatively stable period that enabled human civilization to flourish. But after millennia of human activity, this epoch is quickly making way for the Anthropocene.

The Anthropocene is distinguished by a myriad of imprints on the Earth including the proliferation of plastic particles and a noticeable increase in carbon dioxide levels in sediments.

A New Chapter in Earth’s History

The clearest identified marker of this geological time shift, and the chosen golden spike for the Anthropocene, is radioactive plutonium from nuclear testing in the 1950s.

The best example has been found in the sediment of Crawford Lake in Ontario, Canada. The lake has two distinct layers of water that never intermix, causing falling sediments to settle in distinct layers at its bed over time.

While the International Commission on Stratigraphy announced the naming of the new epoch in July 2023, Crawford Lake is still in the process of getting approved as the site that marks the new epoch. If selected, our planet will officially enter the Crawfordian Age of the Anthropocene.