Source Of Snowball Earth Solved

 Geologists have solved the source of Snowball Earth, a period when the planet's environment was an extreme "Icehouse".

"Imagine the Earth almost completely frozen over," said the study's lead author, ARC Future Fellow Dr Adriana Dutkiewicz.

"We now think we have cracked the mystery: historically low volcanic carbon dioxide emissions, aided by weathering of a large pile of volcanic rocks in what is now Canada; a process that absorbs atmospheric carbon dioxide," added Dr Dutkiewicz.

Using a computer model, the researchers were able to calculate the CO2 degassing of submarine volcanoes along mid-ocean ridges, revealing that the start of the Sturtian ice age precisely correlates with an all-time low in volcanic CO2 emissions.

The CO2 outflux remained relatively low for the entire duration of the ice age.

Dr Dutkiewicz said: "At this time, there were no multicellular animals or land plants on Earth. The greenhouse gas concentration of the atmosphere was almost entirely dictated by CO2 outgassing from volcanoes and by silicate rock weathering processes, which consume CO2.".

As a consequence, atmospheric CO2 declined to a threshold triggering glaciation, estimated to be below 200 parts per million, less than half of today's level.

https://www.heritagedaily.com/2024/02/source-of-snowball-earth-solved/150502