WASHINGTON (Reuters) - Life on our planet faced a stern test during the Cryogenian Period that lasted from 720 million to 635 million years ago when Earth twice was frozen over with runaway glaciation ...

Explore the concept of 'snowball earth' and recent findings on climate variability during this ancient icy period.

Life on our planet faced a stern test during the Cryogenian Period that lasted from 720 million to 635 million years ago when Earth twice was frozen over with runaway glaciation and looked from space ...

Add Yahoo as a preferred source to see more of our stories on Google. Rocks can hold clues to history dating back hundreds of millions of years. Christine S. Siddoway Around 700 million years ago, the ...

Glaciers reached Cape Cod, Massachusetts, in the most recent ice age about 20,000 years ago. But much harsher ice ages hit the Earth in an ancient geological interval known as "the Cryogenian Period" ...

Were Earth’s oceans completely covered by ice during the Cryogenian period, about 700 million years ago, or was there an ice-free belt of open water around the equator where sponges and other forms of ...

These layered structures called stromatolites from the Cryogenian Trezona Formation were created by biofilms of microbes that formed in a shallow-water tropical environment in South Australia’s ...

Our planet was once a harsh, alien, icy world. Yet this deep freeze may have shaped you, me and all life on Earth ...

Scientists at the University of Southampton have uncovered evidence from ancient rocks that Earth's climate continued to ...

Around 700 million years ago, the Earth cooled so much that scientists believe massive ice sheets encased the entire planet like a giant snowball. This global deep freeze, known as Snowball Earth, ...

Glaciers reached Cape Cod, Massachusetts, in the most recent ice age about 20,000 years ago. But much harsher ice ages hit the Earth in an ancient geological interval known as “the Cryogenian Period” ...