Using information from rocks on Earth’s surface, we’ve reconstructed the planet’s plate tectonics over the past 1.8 billion years. This is the first time that Earth’s geological record has been used so far into the past. This has allowed us to map the past 40% of the planet’s history, as you can see in the animation below. The study, led by Xianzhi Cao from the Ocean University of China, was published in the open-access journal Geoscience Frontiers.

Mapping our planet through its long history creates a beautiful continental dance, a fascinating work of natural art in its own right. It begins with a familiar world map. India then moves rapidly south, followed by parts of Southeast Asia as the ancient Gondwana continent formed in the Southern Hemisphere.

About 200 million years ago (Ma or mega year During the restructuring), when dinosaurs roamed the Earth, Gondwana joined North America, Europe, and Northern Asia to form a large supercontinent called Pangaea. Restructuring then continues backwards in time. Pangaea and Gondwana were formed by the collision of older plates. Over time, an older supercontinent called Rodinia emerged.

It doesn’t end there. Rodinia formed about 1.35 billion years ago when an even older supercontinent called Nuna broke apart.

Why make a map of Earth’s past?

Among the planets of the solar system, Earth is unique in that it has plate tectonics. Its rocky surface is broken into pieces (plates) that rub together to form mountains or split apart to form cliffs, which are then filled with oceans.

Earthquakes and volcanic eruptions, as well as plate tectonics, push rocks from deep underground to high up in mountain ranges. This allows elements deep underground to erode from rocks and mix into rivers and oceans. From there, living things can use these elements.

These essential elements include phosphorus, which forms the framework of DNA molecules, and molybdenum, which organisms use to remove nitrogen from the atmosphere and form proteins and amino acids, the building blocks of life.

Plate tectonics also create rocks that react with carbon dioxide in the atmosphere. Carbon-sequestering rocks have been the primary control of Earth’s climate for much, much longer than the rapid climate change we are responsible for today.

A tool for understanding deep time

Mapping the planet’s past plate tectonics is the first step toward creating a complete digital model of Earth throughout its history. Such a model will allow us to test hypotheses about Earth’s past. For example, why did Earth’s climate experience extreme “snowball Earth” fluctuations, or why did oxygen accumulate in the atmosphere when it did?

In effect, this will allow us to much better understand the feedback between the deep planet and the surface Earth systems that support life as we know it.

There is still a lot to learn

Modelling our planet’s past is crucial if we are to understand how nutrients became available to fuel evolution. The first evidence of complex cells with nuclei, such as all animal and plant cells, dates back 1.65 billion years.

This is close to the beginning of the restructuring and the time of the formation of the supercontinent Noon. We aim to test whether the mountains that grew during the formation of Nuna provided the necessary elements for the evolution of complex cells.

A significant portion of life on Earth occurs through photosynthesis and the release of oxygen. This links plate tectonics to the chemical composition of the atmosphere, and some of this oxygen dissolves into the oceans.

In contrast, some critical metals, such as copper and cobalt, are better soluble in oxygenated water. Under certain conditions, these metals precipitate from solution; in short, they form ore deposits.

Many metals form at the roots of volcanoes along plate edges. By reconstructing where ancient plate boundaries lay in time, we can better understand the Earth’s tectonic geography and help mineral explorers find ancient, metal-rich rocks that are now buried beneath much younger mountains.

In this era of discovery of other worlds in our solar system and beyond, it’s important to remember that there is still much we are only just beginning to understand about our own planet. There are 4.6 billion years left to explore, and the rocks we walk on contain evidence of how the Earth has changed over time.

This first attempt to map the last 1.8 billion years of Earth’s history is a step forward in the great scientific challenge of mapping our world. But it is only the first attempt. In the coming years we will see significant progress from our current starting point.