Relating to or denoting the second period of the Paleozoic era, between the Cambrian and Silurian periods.‘fossils found in Cambrian and Ordovician rocks’
- ‘These are overlain by low-grade metamorphosed sediments and volcanics of Ordovician and Silurian age.’
- ‘Because of the disparate nature of the Ordovician and Cambrian records, it is difficult to make direct comparison between the two events.’
- ‘In contrast, the Ordovician magmatic event postdates the pre-Variscan deformation in the external zone.’
- ‘They interpreted these dates to represent an Ordovician regional metamorphic event.’
- ‘Additional indications for a potential tectonic boundary in Hinnoy are provided by local evidence of an Ordovician event in basement units of the Lofoten area.’
the OrdovicianThe second period of the Paleozoic era, between the Cambrian and Silurian periods, or the system of rocks deposited during it.
The Ordovician lasted from about 510 million to 439 million years ago. It saw the diversification of many invertebrate groups and the appearance of the first vertebrates (jawless fish)
- ‘these are mobile predators that have a fossil record reaching back to the Ordovician’
Late 19th century from Ordovices, the Latin name of an ancient British tribe in North Wales, + -ian.