How a Prehistoric Collision Created Colorado’s Garden of the Gods

Garden of the Gods, Colorado

Millions of years ago, this place was just mud at the bottom of an ancient sea. Then continental plates decided to ram into each other, turning flat sediment layers into vertical rock fins. The whole mess took millions of years to settle.

Here’s the geological story behind Colorado’s breathtaking Garden of the Gods.

Birth of the Ancestral Rocky Mountains

About 300 million years ago, two giant pieces of Earth’s crust collided. The crash between Africa and North America pushed up the land and formed mountains.

This mountain-building event created peaks in the same area where today’s Rocky Mountains stand. Scientists call this process an “orogeny.” Two main mountain ranges formed during this time.

One range, called Uncompahgria, stretched across what is now western Colorado. These mountains would later completely disappear.

The Mountains Start Eroding

As soon as the Ancestral Rocky Mountains formed, they began wearing away. Rain, snow, and ice broke down the rock while rivers carved paths through the new mountains.

Water carried granite pieces, rocks, and sand downhill from the mountain peaks. Streams moved this material east and dropped it at the base of the mountains.

The peaks reached about 2,000 feet high before erosion started reducing them. Over millions of years, nature completely washed away these ancient mountains.

The Fountain Formation Takes Shape

Material from the eroding mountains piled up along their base. Rivers spread rock debris in fan-shaped patterns as they flowed from the mountains.

Everything washed down so quickly that small sand mixed with large boulders in a jumbled mass. Geologists call this mix of different-sized rocks a “conglomerate.”

These layers grew to 1,200 feet thick. Over time, the weight of upper layers squeezed the bottom layers into solid rock, creating what we now call the Fountain Formation.

The Red Color Emerges

Water flowed underground through the newly formed rock layers. This water picked up iron from the mountain rocks as it moved. When iron meets air, it rusts.

The same process happened inside the rocks. The iron turned to iron oxide, which painted the naturally light-colored stone deep red.

Different amounts of iron created various shades of red, pink, and orange throughout the rock. This explains the colorful bands visible in Garden of the Gods today.

From Sand Dunes to Sandstone

Around 280 million years ago, the climate turned hot and dry. The region became a desert with little rain and strong winds.

Huge sand dunes formed across the land, much like the ones at Great Sand Dunes National Park today. Wind blew sand grains into large piles that grew over time.

The weight of more sand and later rock layers pressed these dunes into a rock type called Lyons Sandstone. This rock has a smoother texture than the rougher Fountain Formation below it.

Burial Under More Deposits

During the next 150 million years, the environment changed many times. Shallow seas covered the land, then pulled back as conditions shifted.

Beaches formed at the edges of seas, while swampy areas developed in other places. Each setting left behind different types of rock layers, including limestone from seas, mudstone from swamps, and sandstone from beaches.

These new layers covered the older Fountain Formation and Lyons Sandstone, protecting them while adding weight that further hardened the rocks below.

The Second Mountain-Building Event

Between 65-70 million years ago, Earth’s crust shifted again during what geologists call the Laramide Orogeny. The Pacific plate pushed hard against North America.

This pressure forced very old crystalline rocks upward. Pikes Peak granite, formed over a billion years earlier, began moving toward the surface.

The modern Rocky Mountains started taking shape during this time. The movement reawakened old cracks in the Earth and created new ones, setting up the unique formations at Garden of the Gods.

The Dramatic Tilt Occurs

The rising granite pushed against the rock layers above it with great force. Flat rock beds bent upward near the edge of the forming mountains.

Think of the rock layers like a stack of papers on a table. Now imagine pushing one edge up: the papers tilt.

The same thing happened to these rock layers, but on a massive scale. Layers that once lay flat now stood nearly vertical.

Despite the extreme bending, the rocks kept their original order, showing millions of years of Earth’s history on edge.

The Rampart Fault’s Role

During mountain building, a large crack formed in Earth’s crust called the Rampart Fault. This fault runs right through Garden of the Gods.

Rocks on either side of this fault moved differently. Some layers turned completely vertical, while others tilted at about 35-degree angles.

This explains why rocks in different parts of the park stand at various angles. The fault continues for 30 miles north of the park, affecting rock formations throughout the region.

Differential Erosion Creates the Fins

Once the rock layers stood on edge, wind and water went to work on them. Softer rocks like shale and mudstone wore away quickly.

Harder sections of sandstone and conglomerate resisted erosion better, remaining as tall ridges. The difference in how fast various rock types erode is called “differential erosion.”

Weather continued shaping these formations over millions of years. The spaces between the remaining hard rock layers created the dramatic fins and spires we see today.

Visiting Garden of the Gods

Find Garden of the Gods at 1805 N. 30th Street in Colorado Springs, Colorado. The park remains free to visit and stays open year-round from 5 AM to 11 PM daily.

You can walk the 1.5-mile paved Perkins Central Garden Trail to see the most dramatic rock formations up close.

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