The Cryogenian period (~720–635 million years ago, Ma) is defined by a pair of these Snowball Earth events; the longer glaciation (Sturtian) lasted for ~57 million years, followed by a brief ...

Dec. 19, 2024 — Fossilized skeletons and shells clearly show how evolution and extinction unfolded over the past half a billion years, but a new analysis extends the chart of life to nearly 2 ...