Profilbild

„Royal arch, desert varnish, trees, Grand Staircase“

aus der Galerie von Tom Dempsey
Über dieses Bild:

In early spring, leafless trees and desert varnish frame a royal arch in canyon walls along Lower Calf Creek Falls trail in Grand Staircase Escalante National Monument, Utah, USA. Manganese-rich desert varnish requires thousands of years to coat a rock face that is protected from precipitation and wind erosion. The varnish likely originates from airborne dust and external surface runoff, including: clay minerals, oxides and hydroxides of manganese (Mn) and/or iron (Fe), sand grains, trace elements, and usually organic matter. Streaks of black varnish often occur where water cascades over cliffs, but wind doesn’t sculpt its shape. Varnish color varies from shades of brown to black. Manganese-poor, iron-rich varnishes are red to orange, and intermediate concentrations are shaded brown. Manganese-oxidizing microbes may explain the unusually high concentration of manganese in black desert varnish, which can be smooth and shiny where densest. Hike Lower Calf Creek Falls trail 6 miles round trip (600 feet gain). Directions: From the town of Escalante, drive 15 miles east on Scenic Byway 12 to Calf Creek Recreation Area day-use parking and campground.

Bildnummer: 6cb0e1c
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Uwe Karmrodt gefiel dieses Kunstwerk 2013-11-05 18:21:27 UTC
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