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December 29, 2005

This image (actually a mosaic of several images) depicts a considerable portion of Eastern and Southern Europe. The continent began to coalesce approximately 3 billion years before present, about 1.5 billion years after the formation of the planet itself.

The outer layer of the Earth is divided into two regions: the lithosphere and the asthenosphere. The former is essentially the rock-like crust; its thickness varies from about 1.6 kilometers (1 mile) to about 150 kilometers (93 miles). The latter is deformed by heat and pressure and is therefore more fluid or "plastic"; estimates of its thickness range from 100 to 300 kilometers (62 - 186 miles).

The plate or section of the lithosphere upon which Europe rests (called the Eurasian plate) is actually much bigger than the continent itself, stretching from the Eastern portion of Siberia into the middle of the Atlantic Ocean.

Many of the geologic features visible in this image were in large part created by the collision of the Eurasian plate with other continental plates, through a process called "orogeny" or mountain building.

The Alps, the Carpathians, and Urals were all formed in this manner. The process is on-going; the African plate continues to grind into Europe, causing earthquakes in Greece and Turkey, while the distance between Europe and North American steadily increases.

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