Some Features on the Nugget/Navajo Sandstone, San Rafael Swell, Utah

A dinosaur track in the top of the Jurassic Nugget Sandstone (also called the Navajo Sandstone) on the San Rafael Swell, Utah. This was located in the bottom of a wash and has since been covered or eroded away. The middle toe must have been loaded with mud as the dinosaur stepped into this spot.

An interesting structure on the same surface as the dino print above. I thought this might be a burrow of some type, but my friend and colleague, Dr. Steven Hasiotis, who is an expert in trace fossils was unconvinced. We decided it must be some kind of fluid "pebble dike" like structure, where the solid sandstone was broken up and then redeposited as water or other fluids moved through the rock.

Also found on the Nugget Sandstone on the San Rafael Swell, this picture shows the individual avalanche deposits of sand that tumbled down the dune face before this became a rock.

Here is another view of this dune in the Nugget Sandstone. You can see the surface with the avalanche deposits in the foreground and in the background a lower face of the dune that is covered with ripples.

In one spot on this petrified dune, there were these small circle-like structures (see piece of chalk for scale). I am not sure what caused them.

Just below the dunes shown above, the sandstone is ribbed with giant polygonal cracks filled with sandstone that is slightly more resistant to erosion. My colleague, Ron Blakey at Univ. of Northern Arizona has published several papers on these structures.

One of the most interesting features to me found on a couple of the dune faces were these  triangular and rectangular structures. They represent salt or gypsum that crystallized in the sand and, after leaving an impression, dissolved away.

Another probable dinosaur undertrack on the top of the Nugget.

Along the edge of the wash, a series of these possible dino tracks seem to form a trackway.

Central Utah Scenery

Cliff edge near Hell's Backbone, Utah.


Red Canyon, near Bryce Canyon National Park after a fall shower.


Cross-bedded sandstones along Highway 12 near Boulder, Utah.


Cedar Breaks National Monument in October.


Aspens on south end of Aquarius Plateau, Utah.


Morning light at Cedar Breaks National Monument.


Desert rain storm at lower Blues viewpoint near Henrieville, Utah.


Aspen woods, central Utah.


View of Boulder Mountain from Hell's Backbone, near Escalante, Utah.


Scenery near Hell's Backbone, near Escalante, Utah.


Fall flow from Utah's largest spring, Mammoth Spring near Cedar Breaks Natl Mon

Jurassic Rocks near Page, Arizona

Pink cross beds in the Page Sandstone, near Judd Hollow, Arizona.


Ancient sand dune in the Navajo Sandstone.


Lake Powell, near Wahweap marina.


Pink cliffs of the Tertiary age Claron Formation.


Slot canyons in Judd Hollow, Arizona.


Concretions in the Page Sandstone.


Fossil mudcracks in the 170 million-year-old Page Sandstone.


Jurassic rocks in Judd Hollow, Arizona.


Colorful cross beds in the Page Sandstone near Judd Hollow, Arizona.


Cliff of Navajo Sandstone, capped by Harris Wash and Judd Hollow Members of the Carmel Formation. Photo taken in Judd Hollow.


Sandstone hoodoos south of Page, Arizona in the Carmel Formation.

Henry Mountains, Utah

Photos of the Henry Mountains in southeastern Utah, May 2007
(All photos were taken by Urthman, and may not be republished without permission)

Capitol Reef National Park at sunset

Photos of Capitol Reef National Park at sunset May 2007
(All photos were taken by Urthman, and may not be republished without permission)