Activity board

419.2 million and 358.9 million years ago

The Devonian Period

The climates of both Laurssia and Gondwana were tropical based on tectonic evidnece providing an insight of their predicted locationsIt is agreed that overall the Devonian period was a warmer time in Earth's history with little evidence of glacier deposits

Climate

Based on studies of coral growth lines from the time it could be estimated that a Devonian Year was about 400 days with a lunar cylce of 30.5 days (1 more than today)

Devonian Time

The planet was primarly a habital ocean that covered about 85% of the surface.The remaining 15% of the surface consisted of tropical land

Earth's Surface

Laurussia (North America, Europe, Greenland)Gondwana (South America, Australia, Antarctica, India)85% of Earth's surface is ocean

Landmasses

419.2 million and 358.9 million years ago

The Devonian Period

Commonly known as the "Age of Fishes" the Devonian was home to the largest evolution of fish in Earth's history. Giving rise to new fish such the most dominant organisms from this period the Placoderms.This gave way to a ocean full of new life with both the surface and deep waters being home to tons of new organsims Along with a flourishing ocean floor with an abundance of corals and burrowing organisms The evidence of plant debris in Devonian deposits it can be assumed groves of trees covered the two supercontinents. The Divonian aslo had the first tetrapods to walk the land

Life

The Devonian was able to foster a flourishing environment for invertebrates, vertebrates, and plants closing refelcting the types of organisms we have today

419.2 million and 358.9 million years ago

The Devonian Period

Black Shale with Trilobite fossil

While a specifc cause can not be pinpointed many theories that are supported by geographical evidence along with geological evidence.One theory suggests metorites were a factor in this events with evidence from Sweeden with a 40 mile diameter crater dated to be formed approximately 377 million years ago within the Kellwasser Event.Other evidence points to environmental causes from the black shale dated to the time which indicates low oxygen conditions. While it can not be determined what would have caused oxygen levels to drop, it has been theorized to be caused be extreme changes in the climate either warming or cooling

Causes

Throughout the Devonian there were many periods of anoxic or hypoxic sedimentation that lead to widespread extinction events.One event of note that seperates the middle andupper Devonian period is the Taghanic Event which caused mass extinction of for goniatites, corals, and brachiopods.Another extinction event was the Kellwasser Event which saw the extinction of more species from goniatites, corals, and brachiopods.The last event of note was the Hangenberg Event which saw the end of more goniatites along with trilobites.

Extinctions

419.2 million and 358.9 million years ago

The Devonian Period

Dunkleosteus: One of the largest armored fish of the period

ProQuest Ebook Central. (n.d.-b). https://ebookcentral.proquest.com/auth/lib/fjpw/login.action Search.credoreference.com. (n.d.). https://search.credoreference.com/articles/Qm9va0FydGljbGU6NDYwMjE0 Https://ebookcentral.proquest.com/lib/ucf/detail.a... (n.d.-a). https://ebookcentral.proquest.com/lib/ucf/detail.action?docID=6683001&query=rum

References