The Making of America's Mountain
The granite that make up Pikes Peak was once molten (or liquid) rock. It slowly cooled and hardened miles beneath the earth’s surface, giving the crystals time to grow. Over the last 500 million years several tectonic plates (the earth’s outer layers) have collided and pushed the now-cool granite lying below the surface upward. Around 65 million years ago a tectonic plate under the Pacific Ocean was driving into the North American continent. This movement initiated tremendous, mountain-building pressure below what is now Colorado and created Pikes Peak.
From two million to 10,000 years ago a series of Ice Age climates gripped the land. Alpine glaciers formed on Pikes Peak. These rivers of ice gouged bowl0like hollows and U-shaped valleys. Since then, erosion has continued to sculpt the rugged mountain.
(Inset) Look at a piece of Pikes Peak Granite. You are seeing a rock that’s over a billion years old! Can you see white or clear quartz, pink feldspar and dark, shiny flakes o mica? These large crystals five us clues to the rock’s origin.
Marker is on Pike's Peak Toll Road.
Courtesy hmdb.org
