Experience 1.8 billion years of tectonic plates dancing on Earth’s surface in new animation

Using information from inside rocks on Earth’s surface, we have reconstructed the planet’s plate tectonics over the past 1.8 billion years.

This is the first time that Earth’s geological data has been exploited in this way, going back so far in time. This has allowed us to attempt to map the planet over the remaining 40% of its history, as you can see in the animation below.

The work, led by Xianzhi Cao of Ocean University in China, is now published in the open-access journal Frontiers of geosciences.

A beautiful dance

Mapping our planet through its long history creates a magnificent continental dance, fascinating in itself and a natural work of art.

It all starts with the familiar world map. Then India moves rapidly south, followed by parts of Southeast Asia as the ancient continent of Gondwana forms in the southern hemisphere.

About 200 million years ago (Ma or mega-annum in the reconstruction), when dinosaurs roamed the Earth, Gondwanaland was joined to North America, Europe, and northern Asia to form a large supercontinent called Pangaea.

The reconstruction then continues over time. Pangea and Gondwana themselves formed from collisions of older plates. Over time, an earlier supercontinent called Rodinia appeared. And that’s not all. Rodinia, in turn, arose from the breakup of an even older supercontinent called Nuna about 1.35 billion years ago.

Why map the Earth’s past?

Among the planets in the solar system, Earth is the only one to have plate tectonics. Its rocky surface is divided into fragments (plates) that collide and create mountains, or separate and form chasms that are then filled with oceans.

In addition to causing earthquakes and volcanic eruptions, plate tectonics also pushes rocks from deep within the earth to the tops of mountain ranges. This allows elements that were deep underground to erode from the rocks and eventually flow into rivers and oceans. From there, living things can exploit these elements.

Among these essential elements are phosphorus, which forms the structure of DNA molecules, and molybdenum, which organisms use to extract nitrogen from the atmosphere and make proteins and amino acids, the building blocks of life.

Plate tectonics also exposes rocks that react with carbon dioxide in the atmosphere. Rocks that trap carbon dioxide are the primary regulator of Earth’s climate over long time scales, much longer than the tumultuous climate change we are experiencing today.

A tool for understanding deep time

Mapping the planet’s past plate tectonics is the first step toward building 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 Earth’s climate experienced extreme fluctuations, such as those of the “Snowball Earth,” or why oxygen accumulated in the atmosphere at that time.

Indeed, this will allow us to better understand the feedbacks between the deep planet and the Earth’s surface systems that support life as we know it.

There is still so much to learn

Modeling our planet’s past is essential to understanding how nutrients became available to fuel evolution. The first evidence of complex cells with a nucleus, like all animal and plant cells, dates back 1.65 billion years.

We are at the dawn of this reconstruction and at a time close to the formation of the supercontinent Nuna. We want to test whether the mountains that grew at the time of Nuna’s formation could have provided the elements necessary for the complex evolution of cells.

Much of life on Earth photosynthesizes and releases oxygen. This links plate tectonics to atmospheric chemistry, and some of this oxygen dissolves into the oceans. In turn, a number of essential metals, such as copper and cobalt, are more soluble in oxygen-rich water. Under certain conditions, these metals are then precipitated out of solution: in short, they form ore deposits.

Many metals form in the roots of volcanoes that lie along plate margins. By reconstructing ancient plate boundaries over time, we can better understand the tectonic geography of the world and help mineral explorers find ancient metal-rich rocks now buried beneath much younger mountains.

As we explore other worlds in the solar system and beyond, it is worth remembering that there is so much on our own planet that we are only just beginning to glimpse.

There are 4.6 billion years to study, and the rocks we walk on contain evidence of how the Earth has changed over that time.

This first attempt to map the 1.8 billion years since the Earth was created is a leap forward in the great scientific challenge of mapping our world. But it is only a first attempt. The coming years will see considerable progress from where we started.

This article is republished from The Conversation under a Creative Commons license. Read the original article.