Smithsonian National Museum of Natural History Geologic Time The Story of a Changing Earth
Presented by the Department of Paleobiology.
The Silurian
Contents
Overview
Silurian Marine Life
The Invasion of Land
Geology and Climate
Evidence
Model of Cooksonia
learn more
sample
Tabulate coral
Eurypterid
Silurian diorama
references and links
Foundational Concepts
Dating Methods
Earth Processes
Life Processes
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Glossary Credits Email Us


Geology and Climate
During the Silurian, Earth underwent considerable changes that had important repercussions for the environment and life within it. Plate tectonic activity continued to shift the continents during the Silurian. The great southern continent of Gondwana drifted farther across the South Pole, while Siberia, Laurentia and Baltica clustered around the equator. Laurentia and Baltica collided at the end of the Silurian, forming a new supercontinent, Euramerica, and raising new mountain ranges. Rising sea level formed a nearly continuous sea from New York to Nevada, and other shallow seas still covered parts of other continents.

The Early Silurian was also a time of global icehouse climate that included great ice sheets at high latitudes. By the middle of the Silurian, however, global climate had become much warmer, comparable to that of most of the Ordovician and Devonian Periods. A new greenhouse phase began, leading to the melting of many large glacial ice sheets, which contributed to a substantial rise in global sea level. The result was a world with distinct north-south climatic zones, much as today. Glaciers remained at high latitudes, but lower latitudes were relatively warm and arid conditions led to the formation of extensive evaporite (salt) deposits near the equator.




Overview | Silurian Marine Life | The Invasion of Land
Geology and Climate



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