A severe
ice age
(
snowball Earth
) occurred 750 to 570 million years ago, and glaciers covered the planet's landmasses, limiting the expansion of life forms.
The ice started to thaw in the late
Proterozoic
.
A severe ice age (snowball Earth) occurred 750 to 570 million years ago,
and glaciers covered the planet's landmasses, limiting the expansion of life forms.