Until Now
BiologyGeology

The great Silurian reefs

Stromatoporoid sponges and tabulate corals build reefs across the tropics on a scale not seen before.

When
Known to
± 5 million years
Era
Silurian, Paleozoic

Silurian reefs, preserved from Gotland to the Michigan Basin, are constructed by stromatoporoids — laminated calcareous sponges — together with tabulate and rugose corals. They form wave-resistant frameworks in shallow tropical seas and support dense communities of brachiopods, crinoids and cephalopods. Some Silurian reef complexes rival modern barrier reefs in scale, and their deeper, turbid variants functioned much like today's mesophotic reefs.

Just before

Just after