POTD March 25, 2014: Thomas Range, Juab County, Utah
Thomas Range, Juab County, Utah
Photographer: Jim Davis; © 2012
Layered volcanic rocks of the Topaz Mountain Rhyolite weather into interesting shapes. The rocks, referred to as stratified tuff, formed as ash fell from the sky and flowed across the ground during the explosive eruption of a volcanic caldera around 7 million years ago.