The Appalachians towered as high as the Himalayas during the Silurian
The Silurian Period defined in the geological record, was sandwiched between the Ordivician and Devonian periods, and lasted from approximately 443 million to 416 million years ago. During the Silurian most of the world's organisms lived in the sea, and the disappearance of species from the fossil record as well as geological evidence suggests that there was a devastating mass extinction at the beginning of the period. Another important event was the closure of the Iapetus Ocean, which resulted in massive mountain-building events.
Movement of Continents
During the Silurian Period, the supercontinent Gondwana, consisting of Africa, South America, Australia, India and Madagascar, continued to travel south over the Southern Pole. Baltica, Laurentia, and Siberia were clustered around the equator. By the end of the Silurian, Baltica and Laurentia collided in the Caledonian and Appelachian Orogenic events. This led to the formation of the Euramerican supercontinent.
Mountain Building Events
The Iapetus Ocean was between the continents of Laurentia and Baltica. The closure of the ocean during the Silurian period brought the two continents together and resulted in a period of extensive mountain building. The Appalachian Mountains, on the eastern margin of Laurentia, and the Caledonian Mountains in Scotland were raised up as a result of the collision between the two continents. Geological evidence suggests that both these mountain ranges once equaled or, even surpassed, the Himalayas in height.
Ordivician Silurian Mass Extinction
The third-largest ever mass extinction discovered in the fossil record occurred at the end of the Ordivician and the beginning of the Silurian. Called the Ordivician-Silurian Mass Extinction, the event wiped out up to 85 percent of sea life in some regions. Evidence in the geological record, such as the presence of glacier-deposited dropstones among smaller rocks characteristic of a marine environment, indicate that the onset of glaciation may have been the culprit. Scientists theorize that the formation of a huge southern ice sheet may have caused a global drop in temperature and an eustatic sea-level, resulting in the mass extinction.
Locations of Silurian Rocks
Today, you can find few rocks belonging to the Silurian period in the Americas. Silurian rocks outcrop along the continents' primary mountainous regions, including the Appalachians, the Andes, and the Rockies. Searchers find the most considerable areas of Silurian rocks in Newfoundland and other regions of northern and eastern Canada. The main Silurian outcrops in Europe are in the regions where the Caledonian Mountains once reached towards the stratosphere. There are extensive Silurian outcrops in north-western and southern Africa, and important outcrops in the Ural Mountains, in eastern Russia. Australia also possesses some major outcrops.
Tags: mass extinction, Baltica Laurentia, between continents, Caledonian Mountains, evidence suggests, evidence suggests that, fossil record