Over 500 million years ago, life on Earth was booming during the Cambrian explosion.
However, at the same time, tectonic plates were colliding, forming mountains, and triggering events that led to a mass extinction.
This period of mountain building caused magma to rise to the Earth’s surface, releasing large amounts of greenhouse gases into the atmosphere and causing rapid climate change.
The resulting extinction wiped out many animal groups, including reef-building marine sponges called archaeocyathids and small conical-shelled animals known as hyoliths.
“It’s unusual to point to a tectonic cause for an extinction event,” said John Goodge, a professor emeritus at the University of Minnesota Duluth, “but the evidence is compelling.”
Goodge and his colleagues made the connection to plate tectonics by comparing field notes from Antarctica and southern Australia. These locations, once near each other around the equator as part of the supercontinent Gondwana, showed nearly identical records of mountain building right before the extinction.
The research, which began in the 1990s, is published in the journal Science Advances. It all started when Goodge and fellow scientists set up their bright yellow and blue tents on a snow-covered glacier in Antarctica.
Over two field seasons, they traveled by helicopter and snowmobile to the Holyoake Range, examining fossils from the carbonate reef structures to pinpoint the extinction. A separate team found similar records in Australia in 2011.
“You never know when something you did decades ago is going to come together in a new way,” Goodge said.
This discovery highlights how tectonic activity can have profound impacts on Earth’s climate and life, leading to significant extinction events. It also shows the importance of geological research and how findings from decades ago can provide new insights into Earth’s history.
