Sunday, August 25, 2013
Sunday, August 18, 2013
Great white throne" ,Zion National Park, ChelseaStark http://www.chelseastarkphotography.com, a photo by chelseastarkphotography.com on Flickr.
The Great White Throne is a highlight of Zion National Park, itself a world-class showplace of sandstone. The whole edifice consists of the Navajo Sandstone, one of the world's largest sandstone bodies. One of the striking things about the Great White Throne is that while its top is white, its base is red. It is thought that once upon a time the Navajo was a supergiant-class reservoir of petroleum. As the sandstone began to be exposed through erosion, however, the oil and gas escaped, along the way erasing the red sandstone pigments through chemical reduction. This would have been during Cretaceous time, when the atmosphere was extremely high in carbon dioxide compared to today. Whether the massive oxidation of the Navajo oil reservoir and others like it influenced the global atmosphere is an intriguing research problem.