July 2014, The Gunnison River drops an average of 34 feet per mile through the entire canyon, making it the 5th steepest mountain descent in North America. By comparison, the Colorado River drops an average of 7.5 feet per mile through the Grand Canyon. The Black Canyon is so named due its steepness which makes it difficult for sunlight to penetrate into its depths. As a result, the canyon is often shrouded in shadow, causing the rocky walls to appear black. As you can see the walls are far from black. Pink streamers of pegmatite animate the towering cliffs of the canyon at Painted Wall overlook. This granite-like igneous rock formed as hot magma forced its way into cracks. It cooled slowly, allowing large crystals to form. The pegmatite is loaded with shiny muscovite (mus'-ko-vite) mica and large crystals of a pinkish mineral called potassium feldspar.
July 2014
