Red Rocks Amphitheatre is a geological phenomenon located just west of Denver in Morrison, Colorado.  These magnificent rocks were formed as a result of layers of sediment which once settled at the seafloor of an ancient ocean.  Over the course of millions of years these layers of sediment were compressed, eventually forming massive chucks of rock. Over 100 million years ago these rocks were uplifted into what would have been the Ancestral Rockies.  After millions of years of weathering these ancient mountains have begun to wear away through the process of erosion, thus exposing the rocks as we see them today.  This region is also known as the Fountain Formation consisting mainly of sandstone.

A view of Red Rocks Park 

The amphitheater is formed from 3 main rocks: Ship Rock on the south face, Stage Rock directly behind the stage and Creation Rock (Pictured Below) on the north face.  This unique rock formation is the world’s only known naturally-occurring, acoustically perfect amphitheater.  From inside the venue the countless layers of sediment can be seen.  These countless layers of sediment tell the story of the millions of years it took to form the monoliths which we currently see.  With its long history it is no surprise that dinosaur bones can also be found throughout the region.

"Creation Rock" as seen from inside of the venue - Notice the layers of sediment

Perhaps one of the most interesting features of Red Rocks, an unconformity line can be found just above the venue.  Picture below is an unconformity line showing a gap of 1.4 billion years! This weekend I even had the privilege to see this amazing feature first hand.  To the left is the Fountain Formation “Red Rocks” as we know them today, which is formed from compacted sand and gravel that is 300 million years old.  To the right is Precambrian Gneiss, gray metamorphic rocks, stained red, which formed 1700 million years ago.  This occurrence could be the result of a tilt in the rocks, which later eroded, allowing new layers of sediment to form on top.  

The Great Unconformity of Red Rocks Amphitheatre 

 My pup Gaia and I checking out the unconformity up close

It has already been a treat to begin to explore the physical geogprahy of Red Rocks Amphitheatre.  Its  features are a true testament to the incredible power of nature and its ability to literally move mountains.  

Sources:

All photographs were taken by myself, except the final photo was by a group of strangers who I gave a little geology lesson about the unconformity too.

http://www.nature.nps.gov/geology/parks/romo/

http://www.redrocksonline.com/ABOUTUS/HistoryGeology.aspx

http://geology.about.com/od/geoprocesses/a/unconformities.htm

http://geology.about.com/od/geology_co/ig/redrocks/