Ordovician Period

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Tej Patel

Ordovician Period

Timeline

-3 Stages of the Ordovician Period- Lower, Middle, and Upper Stages

Lasted for around 45 million years.

Floian Stage

- Increase in the diversity and abundance of graptolites.

Graptolites

- tiny extinct animals that lived in groups or colonies- they could live on the sea floor and grow upward just like a plant

Termadocian stage

- Interval where planktonic graptolites where widely distributed around the world.

Stages of Lower Ordovician

Darriwilian Stage

- Marks the progressive increase in relative abundance of diplograptid graptolites.

Isograptus

- extinct genus of graptolites

Dapingian Stage

- Spans the evolutionary development of Isograptus.

Stages of Middle Ordovician

Hirnantian Stage

-Marks the first appearance of the graptolite Akidograptus ascensus.

Kaitan Stage

- Started as the peak diversity of species- Followed by the most sever depletion in diversity the Ordovician.

Sandbian Stage

- Grapolites expanded in diversity through the Dicranograptidae.

Stages of Upper Ordovician

Life

• Reef ecosystems consisted of mainly algae and sponges

• Shallow seas became breeding grounds for graptolites

• Oldest complete vertebrate fossils, typical fish had bony shields on their heads and tails.
• Early terrestrial anthropods are known form this time, as are indications of early land plants.

Geography

Environment

• Most of the world was in a supercontinent Gondwana which moved towards the South Pole.
• North America rose from the sea during this period.
• During the Upper stages, a major glaciation centered in Africa occurred, which resulted in mass extinctions.
• Climate fluctuations became extreme as glaciation continued.

The upper stage glaciation in africa

Major Event

• During the middle stages, tectonic plates began to shift causing uplifts in the shallow seas which led to glaciation.

• A major glaciation occurred in Africa, which led to a mass extinction of species.

• Nearly all conodonts disappeared in North America.

• Some trilobites, echinoderms, brachiopods, bryozoans, graptolites, and chitinozoans also became extinct.

https://www.britannica.com/science/Ordovician-Period

https://ucmp.berkeley.edu/ordovician/ordovician.php

The Great Ordovician Biodiversification Event (UCF Library)https://ebookcentral.proquest.com/lib/ucf/reader.action?docID=908991

The Geological Time Scale 2012 (UCF Library)https://ebookcentral.proquest.com/lib/ucf/reader.action?docID=980015&ppg=519&pq-origsite=primo

Refrences

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