The Ordovician (/ ɔːrdəˈvɪʃi.ən, - doʊ -, - ˈvɪʃən / or-də-VISH-ee-ən, -⁠doh-, -⁠VISH-ən) [9] is a geologic period and system, the second of six periods of the Paleozoic Era, and the second of twelve periods of the Phanerozoic Eon.

2024年12月24日 · Ordovician Period, in geologic time, the second period of the Paleozoic Era. It began 485.4 million years ago and ended 443.8 million years ago. The interval was a time of intense diversification (an increase in the number of species) of marine animal life in what became known as the Ordovician radiation.

During the Ordovician period, part of the Paleozoic era, a rich variety of marine life flourished in the vast seas and the first primitive plants began to appear on land—before the second...

2012年8月10日 · The Ordovician* lasted about 45 million years and saw the transition from very primitive to relatively modern life-forms in the seas. The “Ordovician radiation” which followed the late Cambrian extinctions, lead to a tripling of marine diversity, the greatest increase in the history of life, and giving the highest levels of diversity seen ...

2023年4月28日 · Beginning in the Ordovician Period, a series of plate collisions resulted in Laurentia, Siberia, and Baltica becoming assembled into the continents of Laurussia by the Devonian and Laurasia by the Pennsylvanian (also see Cambrian Period).

The Ordovician Period lasted almost 45 million years, beginning 488.3 million years ago and ending 443.7 million years ago.* During this period, the area north of the tropics was almost entirely ocean, and most of the world's land was collected …

2018年5月17日 · In geologic time, the Ordovician Period, the second period of the Paleozoic Era, covers the time roughly 505 million years ago (mya) until 438 mya. The name Ordovician derives from that of the Ordovices, an ancient British tribe.

Ordovician Period, Interval of geologic time, 485.4–443.4 million years ago, the second oldest period of the Paleozoic Era. It follows the Cambrian and precedes the Silurian Period. During the Ordovician, many of the landmasses were aligned in the tropics.