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.

Red Cliffs, Washington County, Utah - January 2013

When the weather is not so good in northern Utah in January, you can always head south where the sun is usually shining. Here are a few photos I took on my way home from a conference in St. George, Utah at the Red Cliffs Recreation Area and preserve. Also included are a few pictures of the rocks around the Quail Creek reservoir.

 Red Cliffs with Pine Valley Mountains peaking through on the right.

 Narrow underpass under the I-15 freeway to access the Red Cliffs Recreation Area.

 Historic Orson Adams home at Red Cliffs with arch in background.

Historic Orson Adams home. The home was built between 1862 and 1865. Orson Adams was a veteran of the Mormon Battalion. The Adams house is the only intact structure that remains of the short-lived Mormon pioneer settlement of Harrisburg.

Sandstone outcrops near the Red Cliffs campground.

More sandstone outcrops  near the campground.

Pine Valley Mountains, a granite intrusion, in the rear with the Red Cliffs in front. The granite intruded into the area about 20-21 million years ago, warping up the surrounding rock layers. This type of intrusion is called a laccolith.

Map showing the location of the Red Cliffs Recreation Area and campground.

 View of the Pine Valley Mountains in January.

Scattered granite boulders washed out from the Pine Valley Mountains.

Virgin anticline (fold) at the north end of the Quail Creek reservoir. The thin sandstone cliff capping the top of the hills is the Shinarump Conglomerate Member of  the Triassic Chinle Formation. The darker red and lighter striped red and gray rocks below are the Upper Red Member and Shnabkaib Member of the Triassic Moenkopi Formation.

Exposures along the west side of Quail Creek reservoir of the Triassic Moenkopi Formation capped by a thin ledge of Shinarump Conglomerate. The dark brick red rock layers are the Upper Red Member of the Moenkopi and the lighter reddish pink and gray layers are the Shnabkaib Member of the Moenkopi, where the gray layers are mostly gypsum. 

Elephant Toes and other great spots in Dinosaur National Monument

There is more to see in Dinosaur National Monument than the dinosaur bones.

 Elephant Toes, an erosional oddity in the Nugget Sandstone of Dinosaur National Monument along the Cub Creek road.

The Green River at Split Mountain campground and picnic area in Dinosaur National Monument. The red rocks in the middle of the photo are the Triassic Moenkopi Formation. The large white rounded mountain to the left is Permian Weber Sandstone, and the ridge of sandstone on the right above the red beds is the Garta Member of the Triassic Chinle Formation.

Here in the foreground the prominent sandstone outcrops on the left side belong to the Gartra Member of the Chinle Formation. The central reddish saddle is the upper unnamed member of the Chinle Formation (lower half of the saddle) and what we are calling the Bell Springs Formation (upper half of saddle). The prominent sandstone on the right that caps the red beds is the Nugget Sandstone.

Tan Nugget Sandstone contrasts with the whiter Weber Sandstone in this photo taken along the Cub Creek Road in Dinosaur National Monument.

Permian Weber Sandstone outcrops along the Green River at Split Mountain campground and picnic area in Dinosaur National Monument.

Triassic Gartra Member of Chinle Formation along road to Split Mountain campground, Dinosaur National Monument.

These last three photos were taken in 2002 on an earlier trip to Dinosaur and are re-posted here from an earlier blog.

Folded Weber Sandstone as viewed from the Blue Mountain road just south of Dinosaur National Monument.

View of the Green River from Harper's Corner in Dinosaur National Monument.

View of Echo Park, the junction of the Yampa and Green Rivers, from Harper's Corner in Dinosaur National Monument.

A Few Photos from the Archives

Thistle Landslide in Spanish Fork Canyon, Utah in the spring of 2000.

Light green Jurassic Curtis Formation atop the brown stripes of the Summerville Formation on the San Rafael Swell, Utah

Light greenish gray beds of the Tertiary Green River Formation overlying red beds of the Wasatch Formation in southwestern Wyoming.

Scenic San Rafael Swell, Utah.

Spring flowers on the San Rafael Swell, Utah.

Light green beds of the Cretaceous Cedar Mountain Formation above the purples and reds of the Jurassic Morrison Formation near the Dalton Wells dinosaur quarry north of Moab, Utah.

Red blossoms bloom on a cactus in springtime on the San Rafael Swell, Utah.

In this photo, the brick red Triassic Moenkopi Formation is at the base of the cliff. It is overlain by a greenish and purplish slope of the Triassic Chinle Formation (with the prominent Black Ledge Member near the top of this formation). At the top of the cliff is the massive sandstone cliff of the Triassic (and perhaps partly Jurassic) Wingate Sandstone.

Rock art in the Tertiary Green River Formation of Wyoming. This circular feature is call a concretion.

Sandstones and coal beds of the Cretaceous Blackhawk Formation just west of Helper, Utah.

Vineyards stretch across the Sonoma Valley, California in the spring of 2000.

Clear Lake, California located north of the Sonoma Valley.

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.