The Geology of Pikes Peak

Though the rocks and stones on Pikes Peak may be well over 2.3 billion years old, the formation of the modern Rocky Mountains started relatively recently—a mere 300 million years ago. However, the formation of Pikes Peak actually predates the formation of Rocky Mountains.

About one billion years ago, an immense dome of hot molten rock called magma pushed up from the earth’s core to form what geologists call a batholith. This formation never made it to the surface, but rather remained hidden in the earth’s crust for millions of years. The formation of the Rocky Mountains, and the subsequent appearance of Pikes Peak followed in three relatively recent stages.

The first stage was the creation of what geologists call the Ancestral Rockies. This is when the earth’s crust went through some rather intensive sea floor spreading at the mid-Atlantic Ridge. Unable to absorb the crust as fast as it was being created, the stresses on the North American plate were too high and the crust faulted along what is now the same area as the Rocky Mountains. It was at this time that the huge mass of Pikes Peak first surfaced.

Afterwards, the Ancestral Rockies and Pikes Peak experienced a period of great erosion which virtually leveled the mountains. The debris from this erosion survives in some of the red sedimentary rocks of the area, including Garden of the Gods, one of the areas leading tourist attractions and geologic oddities. After a period of time when the seawater and additional sedimentary rock covered the area, another up-thrust of the earth’s crust formed the present range of the Rocky Mountains and along with it, pushed up the sunken batholith of Pikes Peak. This massive mountain, made entirely of pink granite, has since stood witness to all around.

In more modern days, only 3 million years ago, the erosion caused by glaciers and their runoff in the Pleistocene Ice age have carved many of the features of the mountain. This erosion is greatly expedited by what many call “frost wedging.” The constant freezing, thawing and refreezing of the water is like driving little wedges into the rock and splitting them apart. At the lower elevations, the water seeps deeply into the microfine joints and cracks found in the pink granite. Then, as it freezes, the water expands and cracks the rock apart into large boulders. At the higher elevations, where the colder temperatures keep the water from seeping in as deeply as below, the rock is split into much smaller pieces. So, as you travel higher on the mountain, you’ll likely begin to see much smaller boulders and rocks. After centuries of this freezing and thawing, the rocks eventually break down into soil components. And if you scoop up a handful along the trip, you’ll see a lot of sandy looking particles of granite along with bits of feldspar and shimmering mica that have been eroded from the metamorphic rock.

The Rockies are the longest mountain chain in the world, extending from Mexico to Canada. In the United States there are 91 peaks that are higher than 14,000 feet or fourteeners, as they are called by adventurists. Colorado boasts the largest number of fourteeners with 54. Pikes Peak isn’t the highest in Colorado, but doesn’t miss it by much. The highest is Mt. Elbert near Leadville, and it stands only 318 feet higher at 14,433.