Back to 720 years ago, Earth was completely covered in ice but underwater volcanoes did something that caused a significant impact.
Scientists believed that Earth had an extreme glacial period around 720 to 640 million years ago where the planet was entirely covered in thick sheets of ice, which is the reason why it was called ‘Snowball Earth’.
A new study suggests that the main culprit for the extreme glacial period is the extensive explosion of underwater volcanoes, but they are still unsure what caused the extreme cooling of the planet.
But they believed that the reason for supercontinent Rodinia to breakup is the extreme cooling that happened to the planet. Rodinia comprises most or almost the entire landmass of Earth, and its breakup increased the run-off of water from rivers towards the ocean.
This event highly changed the chemistry of the ocean and greatly reduced the carbon dioxide present in the atmosphere leading to increased ice coverage locking Earth literally into a snowball.
The vast ice sheets covering the planet reflected the sun rays away from Earth, resulting to almost no weather changes until carbon dioxide levels increase when land-based volcanic activity happened warming the atmosphere and rapidly melting the ice.
The breakup of supercontinent Rodinia caused the release of huge volcanic chemicals greatly changing ocean chemistry, and removed the carbon dioxide from the atmosphere and rapidly cooling the planet into an ice ball.
According to lead author Tom Gernon from the University of Southampton, “When volcanic material is deposited in the oceans it undergoes very rapid and profound chemical alteration that impacts the biogeochemistry of the oceans.”
“We find that many geological and geochemical phenomena associated with Snowball Earth are consistent with extensive submarine volcanism along shallow mid-ocean ridges,” he added.
But this model fails to explain how hundreds of meters of thick deposits called ‘cap carbonates’ rested on top of warm waters after the ‘Snowball Earth’ event happened.
They study found out that the breakup of Rodinia caused underwater volcanoes to erupt lavas and produce enormous amounts of pyroclastic rocks called hyaloclastite making oceans very rich in calcium, magnesium, silicon and phosphorus.
“We calculated that, over the course of a Snowball glaciation, this chemical build-up is sufficient to explain the thick cap carbonates formed at the end of the Snowball event,” Gernon explained.
And after the snowball event, life started millions of years later.