Rainbow Falls Historic Site

The draw and natural beauty of falling water

Flowing from the summit of Pikes Peak, the water of Fountain Creek tumbles downhill. The landscape dictates its route as it heads 75 miles to its ultimate destination – the Arkansas River. Along the way, it rolls and winds over granite and sand, through dark forests and a mountain pass. As it nears Manitou Springs, it prepares for its most dramatic show – Rainbow Falls, a 50-foot plunge to shallow pools below.

The waterfall, a product of the topography of decomposing granite and sandstone, has been a popular attraction for generations, drawing attention with its chilled water and picturesque setting, as well as its geologic significance.

Long before the town of Manitou Springs existed, the falls held spiritual significance for Ute Indians, the region’s native people. By the mid-1800s, the falls became a marker on the old Ute Trail, a popular westward passageway. When the Pikes Peak Gold Rush began in 1859, thousands of prospectors passed by the falls on their way to the mines in Cripple Creek. In 1886, the Colorado Midland Railroad began construction in Ute Pass adding to the excitement in the new American West.

Arching bridge greets the future

The bridge that passes over Rainbow Falls and Fountain Creek is unique in its design, one seldom used in the Rocky Mountains, called an open spandrel concrete arch. The Pueblo Bridge & Construction Company built it in 1932 for $44,695. Featuring decorative masonry retaining walls and lampposts (since removed), it’s a 160-foot span that supports U.S. Highway 24 into Manitou Springs.

Crews built the highway on the route of the old Ute Trail. Between 1916 and 1928, the road was upgraded to allow for automobiles, and became a link in the “Coast to Coast Highway”. In 1985 the bridge was added to the National Register of Historic Bridges.

Stewardship of an over-loved local treasure

Since the 1800s, most natural attractions in the area were privately owned. The Ducharme family owned Rainbow Falls, but easements and other problems led to the falls’ disrepair and eventual reputation marred by trash and graffiti. In 2005 and ’06, volunteers began cleaning up this area, and in 2009, the family donated the land to El Paso County. Flooding in 2013 after the Waldo Canyon Fire damaged the area. The Colorado Department of Transportation worked on stabilizing the banks of ravaged Fountain Creek and repairing the road and trail leading to the falls.

A one billion year-old unsolved mystery

The Great Unconformity is a mysterious geologic event – it marks a period in Earth’s history where hundreds of millions of years of rock is missing from the geologic record. You can see examples of this phenomenon at locations around the world including the Grand Canyon, and right here at Rainbow Falls, where an almost 500-million-year gap of missing time exists between the Pikes Peak Granite and the overlying Sawatch Formation.

Geologist John Wesley Powell first observed the phenomenon in 1896 as he traveled through the Grand Canyon. What he saw was even more striking than the rocks exposed here at Rainbow Falls. He observed 500-million-year-old beach deposits that had turned to stone overlying 1.7-billion-year-old warped and twisted metamorphic rock, an age difference of 1.2 billion years!

What does this relationship suggest? Both the area around the Grand Canyon and here at Rainbow falls likely experienced a period of mountain uplift during the late Precambrian age, more than 600 million years ago. As the mountains wore down, the whole region was flooded by an ancient sea that first deposited beach sands and then over time thick deposits of limestone like the grayish Manitou Limestone you can see here.

The story being told in the stone

The tumbling water of Fountain Creek might be the star here, but the rocks behind it tell a dramatic story of upheaval, earthquakes, stretching and shifting of the earth, and the ultimate breakup of supercontinents. Look closely, and you will see Pikes Peak granite, the pink crumbly igneous rock composed of quartz, feldspar and mica that is more than a billion years old. The reddish-brown sandstone is part of the Sawatch Formation, deposited more than 500 million years ago. And the grayish Manitou limestone holds clues to the past in fossils of marine animals from long ago.

The Pikes Peak Batholith

A batholith is a large mass of rock formed from cooled magma far below the Earth’s crust. Pikes Peak is a batholith that is approximately 1.04 billion years old. It is not a volcano; the molten rock that formed it was located more than 3 miles (5km) below the surface of the Earth.

Tiny creatures from a past, vast inland sea

Fossils can be found in the Manitou Limestone of this area. Limestone is mostly calcite, which came from the shell remains of marine organisms.

TRILOBITES: Rarely found, these three-segmented, hard-shelled marine animals once dominated the seas. They are among the earliest known groups of invertebrate animals called arthropods. Today, there are more species of arthropods than all other groups including insects, spiders and shellfish.

CRINOIDS: Often called sea lilies, they were attached to the sea floor by a stalk. They are passive feeders, filtering plankton and other organic sea material with their arms. Hundreds of species still live in the oceans today.

BRACHIOPODS: Marine animals that looked like clams whose shells enclosed their organs, they lived on the sea floor. Today, they are found in very cold water around the world.

Pikes Peak granite – more than just a pretty rock

The igneous rock of the Pikes Peak Batholith contains many types of beautiful minerals in its caverns.

AMAZONITE is a member of the feldspar mineral group. The variety found on Pikes Peak is prized for its blue, jade-like color. It is often found in combination with smoky quartz crystals.

TOPAZ is a rare silicate mineral that usually forms in fractures and cavities of igneous rocks, like Pikes Peak granite. Nearly as hard as diamond, Topaz is a popular gemstone used in making jewelry.