| Popis: |
Paleozoic reef formation developed cyclically, and its global termination has been caused by the biological reasons — biotic crises and mass extinctions near the borders early and middle Cambrian, Ordovician and Silurian, Frasnian and Famennian, Serpukhovian and Bashkirian, Permian and Triassic. The Early Cambrian reef formation has ended along with disappearance of archaeocyathid. In the later stages reefs were much more difficult ecosystems, and they stopped developing before the full extinction of the reef-building communities. The interruption of reef formations within the separate stages have been connected with the geological and paleogeographic reasons – volcanism, regression, climate aridization etc. |
