Eroded cross-section of an ancient sand blowout
Cross section of an ancient dune squirt pipe turned to rock in Navajo sandstone, Zion National Park. Disruptions (ancient earthquake?) in the ancient sand dunes caused localized liquifaction of the sand grains in small columns or pipes that squirted fluidized sand and water through the dune. (Jumping up and down in wet sand at the beach is a great way to show sand liquification in action). Note how the circle cuts through the deposited layers. The jiggling set up standing waves that partially sorted the sands in the tubes, seen as the concentric rings inside the circle. Later, the whole structure, dune layers and sand tubes, were turned into stone, uplifted, and eroded to reveal the cross-section we see here.
For a broader view of the location see: www.flickr.com/photos/31678681@N07/10962447165/
Eroded cross-section of an ancient sand blowout
Cross section of an ancient dune squirt pipe turned to rock in Navajo sandstone, Zion National Park. Disruptions (ancient earthquake?) in the ancient sand dunes caused localized liquifaction of the sand grains in small columns or pipes that squirted fluidized sand and water through the dune. (Jumping up and down in wet sand at the beach is a great way to show sand liquification in action). Note how the circle cuts through the deposited layers. The jiggling set up standing waves that partially sorted the sands in the tubes, seen as the concentric rings inside the circle. Later, the whole structure, dune layers and sand tubes, were turned into stone, uplifted, and eroded to reveal the cross-section we see here.
For a broader view of the location see: www.flickr.com/photos/31678681@N07/10962447165/