Earth
18,000 years ago

What's going on here?

• Although the past 5 million years have been quite a bit colder than average, only the Pleistocene Epoch is commonly known as the 'Ice Age'. This term is deceptive because 'ice ages' have several periods of colder (ice house) conditions alternating with warmer (hot house) periods like that of today. During colder times, ice thickness builds and expands from the poles (when there is a continent there to support it!) and sea level drops. 18,000 years ago sea level was several hundred feet lower than today.

Reconstructing ancient Earth

These remarkable figures are produced by C.R. Scotese and the PALEOMAP project. Geologists call these illustrations paleogeographic reconstructions, because they illustrate the reconstructed geography of our Earth at some time in the past.

Making a paleogeographic reconstruction begins by examining several lines of evidence including: paleomagnetism, magnetic anomalies, paleobiogeography, paleoclimatology, and geologic history. By combining all available evidence, geologists are able to construct paleogeographic maps, such as these, that interpret how the geography might have appeared at a specific location and time in the past. Paleogeographic maps are continually being refined as more evidence is collected.

To find out more about how paleogeographic reconstructions are made visit the PALEOMAP project site.

• Learn more about this time period at the PALEOMAP project site.
• Learn more about geologic time.
• Learn more about plate tectonics.

Move forward or back in time.
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Time in millions of years. Jump back to visit any time!

Scotese, C. R., 1997. Paleogeographic Atlas, PALEOMAP Progress Report 90-0497, Department of Geology, University of Texas at Arlington, Arlington, Texas, 37 pp.

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This page was last updated on 01/13/04