Like a red snake twisting beneath the Atlantic, the midocean ridge produces new sea floor, spreading out gradually deep beneath the water.

This slow process of building the planet's youngest crust is vividly displayed on a new government poster map, using bands of color to illustrate the age of the sea floor.

Everywhere less than 180 million years old, the sea floor is "quite young," geologically speaking, reports Peter W. Sloss of the National Geophysical Data Center in Boulder, Colo., where the map was compiled.

Formed at the midocean ridges, sea floor is slowly recycled as it gradually edges toward the ancient continents and is ground beneath them, he explained.

The map displays this process with color changes, displaying aging crust as red, then yellow, green and blue before it disappears beneath the gray continents.

The data center, part of the National Oceanic and Atmospheric Administration, prepared the poster with assistance from the Scripps Institution of Oceanography and institutions in France, Australia and Canada.

Copies of the poster can be purchased for $20 from the NGDC.

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