The geologic story of Red Rock Canyon Open Space began about 300 million years ago when sand and gravel washed down from the ancestral Rocky Mountains to form alluvial deposits which became the Fountain sandstone on the edge of Manitou Springs. 50 million years later, shifting dunes of fine sand drifted into the area to become the red Lyons sandstone of Red Rock Canyon itself. For the following 100 million years, the future Red Rock Canyon was near the edge of the sea - a tidal flat, a shoreline, a delta, and a tidal flat again. Successive layers of sand and mud created the Morrison, Purgatoire, and Dakota formations. Then with rising waters the future Red Rock Canyon became the bottom of a shallow sea. Mud and sand and sharks’ teeth and seashells accumulated, and more sand and more mud - the Colorado group, the Fort Hayes limestone, the Smoky Hill shale, and the Pierre shale.
And then, a wave of geologic upheaval, the Laramide revolution, swept in from the west uplifting a new range of mountains, our Rocky Mountains. The mile deep layer of old sediments was lifted up, deformed, bent until in the future Red Rock Canyon Open Space strata stood on end.
Erosion of the upturned strata created a series of parallel ridges and canyons. Sand and gravel washed down from the Rocky Mountains to form alluvial deposits which became mesas. And, perhaps the story starts again.
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Take the Gazette’s podcast audio tour of Red Rock Canyon geology with geologist Ken Weissenburger:
>> Right click (Ctrl click for Macs) on the link above to download the tour to your computer, then load it to your iPod.
