21 August 2011
The best cross-bedding you’ll ever see
Posted by Callan Bentley
Setting aside the lack of scale, it really doesn’t get any better than that. Click through to make it huge.
This is the Navajo Sandstone, early Jurassic (or late Triassic?) in age. It’s in Zion National Park, Utah. Wind direction was from the right towards the left, as these preserved slip-faces of ancient dunes indicate. The beds are right-side-up, and they have been differentially eroded, causing the cross-beds to jump out in high-relief when lit by the sun directly overhead.
Nine main beds; infinite cross-beds, and also note the joint set orthogonal to the cross-beds.
Callan Bentley is Associate Professor of Geology at Piedmont Virginia Community College in Charlottesville, Virginia. He is a Fellow of the Geological Society of America. For his work on this blog, the National Association of Geoscience Teachers recognized him with the James Shea Award. He has also won the Outstanding Faculty Award from the State Council on Higher Education in Virginia, and the Biggs Award for Excellence in Geoscience Teaching from the Geoscience Education Division of the Geological Society of America. In previous years, Callan served as a contributing editor at EARTH magazine, President of the Geological Society of Washington and President the Geo2YC division of NAGT.
[…] photos were taken in Zion National Park, near Springdale, Utah (real close to the cross-beds I featured a month […]
Hi, I am studying cross bedding at the moment in geology and was wondering if you could tell me how to do an annotated field sketch of this particular photograph- great photo by the way, thanks!