Massive lava outburst may have led to Snowball Earth
https://www.science.org/content/article/massive-lava-outburst-may-have-led-snowball-earth
By Maia Wei-Haas, Science.
Excerpt: About 717 million years ago, a climate catastrophe struck the planet, as temperatures plunged and glaciers enveloped the globe. The cause of this “Snowball Earth” episode has been mysterious, but it took place around the same time as a massive outburst of volcanism. Many researchers thought there might be a connection. But the timing was uncertain. Now, more precise dates, reported last month in Earth and Planetary Science Letters (EPSL) and in November 2022 in Science Advances, show the eruptions preceded the Snowball Earth event by 1 million to 2 million years. The lag points to a particular way the fire could have triggered the ice: through a chemical alteration of the fresh volcanic rocks known as weathering, which sucks carbon dioxide (CO2) from the atmosphere, turning down the planetary thermostat. The studies highlight the power of weathering as a key driver behind shifts in Earth’s climate, and how components of the planet as disparate as rocks and the atmosphere are inextricably linked, says EPSL study co-author Galen Halverson, a sedimentary geologist at McGill University. ...Geoscientists debating the cause of the so-called Sturtian glaciation, which lasted 57 million years, have pointed to a number of possibilities—meteorite strikes, biologic activity, shifts in Earth’s orbit, and more. But recent studies have zeroed in on one of the largest volcanic outbursts ever, preserved today across northern Canada in what’s called the Franklin large igneous province (LIP). The eruptions spewed lava across an area at least the size of Argentina—and perhaps bigger than China....