Cambrian–Ordovician extinction event - Wikipedia
WEBThe Cambrian–Ordovician extinction event ended the Cambrian period, and led into the subsequent Ordovician period. It eliminated many brachiopods and conodonts, and severely reduced the number of trilobite species. [1]
Ordovician Period | Major Events, Extinction, & Facts
WEBAug 9, 2024 · The Ordovician was demarcated in the late 19th century as a compromise in a dispute over the boundaries of the Cambrian and Silurian systems. Studying the rock succession from northwest to southeast within Wales, English geologist Adam Sedgwick named the Cambrian System in 1835.
Ordovician - Wikipedia
WEBThe 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. The Ordovician spans 41.6 million years from the end of the Cambrian Period 485.4 Ma (million years ago) to the start of the Silurian Period 443.8 Ma. [10]
Cambrian - Wikipedia
WEBThe Cambrian (/ ˈ k æ m b r i. ə n, ˈ k eɪ m-/ KAM-bree-ən, KAYM-) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. [5] The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordovician Period 485.4 Ma. [6]
Ordovician Period - Natural History Museum
WEBAug 10, 2012 · The Ordovician saw the replacement of the Cambrian marine fauna composed largely of deposit feeders, such as trilobites, with the Paleozoic fauna dominated by filter feeders arranged in tiers.
Cambrian Period | Definition, Plants, & Animals | Britannica
WEBAug 10, 2024 · Cambrian Period, earliest time division of the Paleozoic Era and Phanerozoic Eon, lasting from 538.8 million to 485.4 million years ago. The Cambrian System, named by English geologist Adam Sedgwick for slaty rocks in southern Wales and southwestern England, contains the earliest record of abundant and varied life-forms.
Ordovician Period Information and Facts - National Geographic
WEBLife at the start of the Ordovician remained confined to the seas with new animals evolving in place of those that didn't survive the Cambrian. Chief among them were the squidlike nautiloids, a...
Ordovician Period summary | Britannica
WEBOrdovician 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.
Ordovician Period—485.4 to 443.8 MYA - U.S. National Park Service
WEBApr 28, 2023 · The Ordovician System rounded out the threefold division of early Paleozoic rocks (i.e., Cambrian, Ordovician, and Silurian), which are all named for Welsh tribes. Recognizing the Ordovician between the Cambrian and Silurian ended a 40-year controversy, eliminated an “overlapping system,” and created a …
The Cambrian Period - University of California Museum of …
WEBThe Cambrian world was bracketed between two ice ages, one during the late Proterozoic and the other during the Ordovician. During these ice ages, the decrease in global temperature led to mass extinctions.