Today’s Outdoor Picture of the Day captures one of Boulder’s most distinctive foothills scenes: the rugged Red Rocks formations viewed from Sanitas Valley Trail. Rising above the surrounding landscape, the warm sandstone fins create a dramatic contrast against the trees, open sky, and softer slopes of Mount Sanitas.
While Boulder’s Flatirons receive most of the attention, Red Rocks offers its own remarkable display of Front Range geology. The formations belong to the Fountain Formation, the same ancient rock unit that created the Flatirons and other famous Colorado landmarks. The sedimentary rock was deposited approximately 280 million years ago from material eroded from the Ancestral Rocky Mountains.
Originally laid down in relatively flat layers, the rock was later tilted upward as the modern Rocky Mountains rose. Wind, rain, snow, ice, and time gradually wore away the softer surrounding material, leaving the sharply angled formations visible today. Their reddish color comes largely from iron minerals within the rock…