The series of extinctions that occurred during the Ordovician and Silurian periods between 445 and 415 million years ago wiped out as much as 85 percent of all animal species on Earth.

They precisely determined the absolute ages of the Katian–Hirnantian boundary (442.65+0.17/−0.23 Ma) and the Ordovician–Silurian boundary (442.33+0.34/−0.33 Ma), constraining the duration ...

Virginia Tech researchers discovered a sixth mass extinction that took place on earth nearly 550 million years ago due to a drop ... The Ordovician-Silurian extinction was 440 million years ...

Ordovician-Silurian. The Ordovician-Silurian mass extinction event may have wiped out some 85 percent of species, including many of the invertebrates this period is known for. Some scientists ...

Ordovician-Silurian Extinction (about 443 million years ago): Around 85% of species went extinct, likely due to a combination of a drop in sea levels and glaciation, followed by rising sea levels ...

Ordovician-Silurian. The Ordovician-Silurian mass extinction event may have wiped out some 85 percent of species, including many of the invertebrates this period is known for. Some scientists ...

They precisely determined the absolute ages of the Katian–Hirnantian boundary (442.65+0.17/−0.23 Ma) and the Ordovician–Silurian boundary (442.33+0.34/−0.33 Ma), constraining the duration ...