Hoodoos

HOODOOS

On our beautiful drive through the Grand Staircase National Monument to Camp K, we passed by some pretty cool structures, such as monoclines, hogbacks, arches, and my favorite, hoodoos!  Hoodoos are found all over High Plateau region of the Colorado Plateau.  They appear to have a "totem pole" type body shape, due to the erosion patterns of alternating hard and soft layers underneath a hard cap-like layer, acting as a roof.  For example, soft mudstone or poorly cemented sandstone covered by a protective layer of well-cemented sandstone, limestone, or basalt.  Further erosion of the softer layers causes the cap to be undercut, eventually falling off (balancing rocks), and the leftover cone is then quickly eroded (NPS.org).  This is a great example of differential erosion.  

Hoodoos are found mostly in hot, dry, desert areas.  On our field studies trip last spring to the Moab area, we saw tons of them, especially at the Fiery Furnace!  Interesting fact: minerals deposited within the rock give them the appearance of different colors throughout their height.  In this image, the iron oxide makes the rock reddish.

Information found from the National Park Service's Bryce Canyon website says that Hoodoos can be eroded when winter snow melt seeps into the cracks and freezes at night, called frost wedging.  When the water freezes, it expands almost 10 percent and pries open cracks in the rock, making them even wider; similar to how a pothole forms in a paved road.  Geologically speaking, they live a short life; their average rate of erosion is 2-4 feet every 100 years.

Information from National Park Service's webpage: http://www.nps.gov/brca/naturescience/hoodoos.htm

Pictured above:  Hoodoos found outside of the visitor center at Red Canyon on Rte 12 west of Bryce Canyon.   They are in the Claron Formation.