What turned the Earth into a giant snowball 700 million years ago? Scientists now have an answer

What turned the Earth into a giant snowball 700 million years ago?  Scientists now have an answer

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Artists’ impression of the Snow Globe. Credit: NASA

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Artists’ impression of the Snow Globe. Credit: NASA

Australian geologists have used plate tectonic modeling to determine the most likely cause of the most extreme Ice Age climate in Earth’s history, more than 700 million years ago.

The study published in geology, helps us understand the working of the thermostat built into the floor which prevents the floor from getting stuck in overheat mode. It also shows how sensitive the global climate is to the concentration of carbon in the atmosphere.

“Imagine the Earth being almost completely frozen over,” said the study’s lead author, ARC Future Fellow Dr. Adriana Dutkiewicz. “This is what happened about 700 million years ago; the planet was covered in ice from the poles to the equator and temperatures dropped. However, why this was so is still an open question.”

“We now think we have solved the puzzle: a historic decline in volcanic carbon dioxide emissions, aided by the weathering of a large pile of volcanic rock in what is now Canada, a process that absorbs atmospheric carbon dioxide.”

The project is inspired by the glacial debris left behind by ancient glaciation from this period which can be strikingly observed in the Flinders Range in South Australia.

A recent geological field trip to the Ranges, led by co-author Professor Alan Collins from the University of Adelaide, prompted the team to use EarthByte computer models at the University of Sydney to investigate the cause and exceptionally long duration of this ice age.


Between 717 and 660 million years ago, the Earth was covered in snow and ice, an ice age that lasted 57 million years. Geologists at the University of Sydney, led by Dr. Adriana Dutkiewicz and Professor Dietmar Müller, have found the likely culprit: all-time low levels of volcanic carbon dioxide in the atmosphere. Credit: Ben Mather and Dietmar Müller/University of Sydney

The Extended Ice Age, also called the Sturtian Glaciation after the 19th-century European colonial explorer of central Australia, Charles Sturt, lasted from 717 to 660 million years ago, a period before the presence of dinosaurs and complex plant life on Earth.

“Various reasons have been proposed for why this extreme ice age began and ended, but the most mysterious aspect is why it lasted for 57 million years, a time period that is difficult for us humans to imagine,” Dr. Dutkiewicz said.

The team returned to a plate tectonic model that shows the evolution of continents and ocean basins sometime after the breakup of the ancient supercontinent Rodina. They connected it to a computer model that calculates carbon dioxide2 Underwater volcanoes degas gases along mid-ocean ridges, sites where plates diverge and generate new ocean crust.


Glacial deposits of the Sturt Formation from the Sturt Glaciation approximately 717-664 million years ago in the northern Flinders Ranges, Australia, near the Arkarola Wildlife Reserve. The paper’s lead author, Dr Adriana Dutkiewicz from the University of Sydney’s School of Earth Sciences, points to a thick layer of glacial deposits. Credit: Professor Dietmar Müller/University of Sydney

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Glacial deposits of the Sturt Formation from the Sturt Glaciation approximately 717-664 million years ago in the northern Flinders Ranges, Australia, near the Arkarola Wildlife Reserve. The paper’s lead author, Dr Adriana Dutkiewicz from the University of Sydney’s School of Earth Sciences, points to a thick layer of glacial deposits. Credit: Professor Dietmar Müller/University of Sydney

They soon realized that the beginning of the Sturtian Ice Age was precisely linked to the lowest volcanic carbon dioxide ever recorded2 emissions. In addition, Inc2 Outflow remained relatively low throughout the duration of the ice age.

“At this time, there were no multicellular animals or land plants on Earth. The concentration of greenhouse gases in the atmosphere was almost entirely determined by carbon dioxide,” Dr. Dutkiewicz said.2 The release of gases from volcanoes and through silicate rock weathering processes, which consume carbon dioxide2“.

Co-author Professor Dietmar Müller from the University of Sydney said: “Geology governed the climate at this time. We believe that the Sturtian Ice Age began because of a double blow: the reorganization of tectonic plates reduced the degassing of volcanic gases to a minimum, whereas the continental Ice Age At the same time, Canada’s volcanic province began to erode, consuming carbon dioxide in the atmosphere2.

more information:
Adriana Dutkiewicz et al., Duration of “snowball terrestrial” glaciation in the Sturtian region associated with exceptionally low mid-ocean outgassing, geology (2024). doi: 10.1130/G51669.1

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