Red Rocks Park: A Journey Through Deep Time

Composed in a deep geologic timeline of deposited conglomerate sediments from the ancient Rocky Mountains; formed by one of Mother Nature’s laws affected by gravity called Superposition, this story begins almost 300 million years ago—when Earth’s landmasses were still part of the supercontinent Laurasia, which later joined with Gondwana to form Pangaea, before eventually splitting apart.

Red Rocks Park in Morrison, Colorado, offers a dramatic glimpse into nearly 300 million years of Earth history. The vibrant red sandstone formations belong to the Fountain Formation, a sedimentary rock layer that began forming in the Late Pennsylvanian Period. These rocks were created by the erosion of the Ancestral Rocky Mountains, an ancient range that once towered where Colorado now lies.

Over millions of years, torrential rivers carried feldspar- and quartz-rich sediments—including sand, silt, and clay—from the mountains into vast alluvial fans and river systems. The result was a strikingly varied sedimentary structure: coarse conglomerates layered with finer materials, colored red by oxidized iron. These materials compacted under pressure, eventually hardening into the durable red rock we see today.

The principle of superposition, one of geology’s fundamental laws, tells us that younger layers are deposited atop older ones. Originally laid down horizontally, the Fountain Formation was later tilted at an angle of nearly 40 degrees due to intense tectonic uplift during the Laramide Orogeny (approximately 72–45 million years ago). This event shaped the modern Rocky Mountains and dramatically altered the orientation of the rock beds.

Another powerful geological feature at Red Rocks is the Great Unconformity visible contact point where nearly 1.5 billion years of missing time separate ancient metamorphic rocks from much younger sedimentary layers. At places like nearby Mt. Morrison, this boundary is so sharp that you can place your hand across a billion-year time gap.

Following the Fountain Formation, the park also preserves rock layers from the Permian Period, including the Lions Formation—buff-colored sandstones that represent ancient arid environments like modern-day desert dunes. This shift in color and composition marks a change in Earth’s climate and ecosystems.

At the close of the Permian, around 252 million years ago, Earth experienced its most catastrophic mass extinction. Roughly 70% of terrestrial species and up to 95% of marine life vanished. Within the park, formations like the Lykins Formation may hold fossilized evidence of microbial life—stromatolites—that either survived or emerged shortly after this event. These stromatolites are still under study and may offer insights into early recovery ecosystems.

Moving into the Triassic Period (around 250–200 million years ago), Red Rocks continues to capture snapshots of Earth’s rebounding biosphere. The eastern edge of the park holds layers that reflect this recovery, where early ancestors of dinosaurs and other reptiles began to thrive.

Throughout these transitions, Red Rocks remained a canvas of geologic forces—deposition, erosion, uplift, and time. The iconic tilted slabs at the Amphitheatre are not only stunning to see, but they also trace a vast history of mountain-building, extinction, and rebirth.

Today, Red Rocks Park stands as one of the most accessible and dramatic records of Earth’s past. Its layers, formations, and fossil traces continue to be studied by geologists and paleontologists—including dedicated researchers and field naturalists working with institutions like the Morrison Natural History Museum, Dr. Robert T. Bakker, and Matthew T. Mossbrucker.

From the Fountain Formation to the rise of life after extinction, Red Rocks Park is not just a place of beauty—it’s a geologic symphony carved by time, revealing the ongoing story of our planet’s ancient past.

Written by T. Johnson © 2025. All rights reserved.