The south side of the La Sal Mountains...

is a well kept secret.

The downtown business hub of Paradox, Colorado on a weekday afternoon.

Buckeye Recreation Area at 7,700 feet (2,350 m) in elevation. It’s a nicely clean and quiet US Forest Service campground.

View of the high La Sals at dusk. No astrophotography was attempted as it is a full Moon.

View to southeast at dawn, looking down the long axis of the Paradox Valley. Early explorers were puzzled as to why the Dolores River flows across this valley rather than along its length, finding it paradoxical. Hence the name Paradox Valley was adopted, and the Middle Pennsylvanian age strata responsible for developing these long and linear collapsed salt-cored anticlines is called the Paradox Formation.

A sandstone-hosted copper deposit...

is found deep in La Sal Creek Canyon where a disseminated ore body formed adjacent to a small normal fault. Following discovery in 1897, the Cashin Mine operated here from 1899 to sometime in the 1950s producing both copper and silver.

Copper mineral staining is common on exposures of the Wingate Sandstone (Lower Jurassic (201.4 Ma - 174.7 Ma)) around the mine site.

Copper mineral staining along a normal fault with a mine adit located on the geologic structure.

Uravan, Colorado may be gone...

but its important nuclear legacy will never be forgotten, having served as the hub of the most productive uranium mining district in the nation. The former company townsite has been erased from most maps following complete environmental remediation of the valley.

Wide panorama from the Star 13 mine portal showing the San Miguel River canyon where the former town and uranium mill was located. Recent remediation efforts resulted in the dismantling of buildings and excavation of radioactive waste and the debris is now sequestered in several containment cells south of the former town site.

The mill and town of Uravan, circa 1970. (Rimrocker Historical Society, donated by Wyatt family.)

Link to NRC closure document: Umetco Uravan.

One of several containment cells in Hieroglyphic Canyon. I measured only background levels of radiation while standing at the fence along the road and snapping this image.

A portal into an atomic future...

at the Mi Vida Mine, the most significant uranium mine in the largest uranium district in Utah. Located south of Moab on the southwest flank of the Lisbon Valley salt-cored anticline, the mineralized zone is contained in the Moss Back Member of the Chinle Formation (Upper Triassic (237 Ma - 201.4 Ma)). Discovered by Charlie Steen and worked from 1952 to 1960, the high grade uraninite ore was transported to the Atlas Mill in Moab for processing. This is what remains at the historic site today.

Mine entrance at the oxidation/reduction boundary in a mudstone in the Chinle Formation.

Wide view of Mi Vida Mine site. Wingate Sandstone forms the jointed escarpment. The red oxidized zone in the Chinle Formation is clearly seen, with the mine entrance (right of center) in the bleached reduced zone.

Tipple to transfer ore from the ore cars onto trucks for transport to the mill for processing.

Electric tender and ore cars, frozen in space and time.

Comprehensive overview: Uranium and Vanadium Resources of Utah (pdf).

Taking the long way...

to the US Post Office in Moab today via the Shafer Trail and Potash Road, about an 80 mile (130 km) long detour. Pretty scenic though!

View from Island in the Sky down to the White Rim in the inner canyon with the La Sal Mountains on the distant horizon.

The Shafer Trail switchbacks descending onto the White Rim Trail.

The Colorado River is running about 2,000 cubic feet per second (cfs) right now where median discharge on this date is around 10,000 cfs.

Thelma & Louise Point overlooking the Colorado River.

Potash evaporation ponds and the gently dipping red beds of the Cane Creek anticline (left of center).

Petroglyph panel along Potash Road depicting a bighorn sheep hunt and bear encounter. The bear glyph is enormous and is more than three feet (1 m) across.

The acid test for a newly tuned bike...

is an early morning lap at the Slickrock Trail of course! The shop mechanics at Poison Spider Bicycles in Moab are top notch and do terrific work. Highly recommended (no commission earned).

Large-scale trough crossbeds dominate the Navajo Sandstone (Lower Jurassic (201.4 Ma - 174.7 Ma)) and the coarsely etched foresets in the rock adds texture to the rolling landscape. The lack of joints and fractures in this area above Moab makes it particularly fun to ride but there is considerable vertical relief as this image shows, making the trail challenging due to the steep ascents/descents and off camber riding.

View down Grandstaff Canyon from the Slickrock Trail with Arches National Park on the skyline.

The hydrogeologic study of Castle Valley...

by the Utah Geological Survey has been published and is now freely available to download. Most importantly, the report concludes: “Our major findings show that water-level trends in the valley-fill aquifer are stable, with little to no long-term decline.” That’s great news and not at all surprising.

Get your copy here, either in paper or digital format: UGS Special Study 176.

Exquisite mudcracks...

displayed on a bedding plane on a fallen slab from the Chinle Formation (Upper Triassic (237-201.3Ma)) near Courthouse Wash. This sedimentary structure formed as muddy sediment dried and contracted due to reduction in water content, then buried and preserved with sandy sediments from a subsequent flood event.

A window into the Paradox Formation...

is found in Onion Creek where the peculiar geology of the salt-dominated formation is on full display. The light-colored gypsum caprock is highly structurally distorted, demonstrating the plastic nature of the buoyant salt body as it rises and displaces other clastic rocks in the geologic section.

View eastward, across the Onion Creek diapir. The Paradox Formation (Middle Pennsylvanian (315.2Ma - 307Ma)) is the light-colored unit in contact with the red beds of the Cutler Formation (Lower Permian (298.9Ma - 273.01Ma)).

Rockin' out at Navajo Rocks...

on the mountain bike trail system during a magnificent autumn afternoon in the high desert.

Red beds of the Dewey Bridge Member of the Carmel Formation (Middle Jurassic (174.1-163.5Ma)) share a sharp contact with the underlying cream-colored Navajo Sandstone (Lower Jurassic (201.3-174.1Ma)). (Click to enlargenate.)

The highest summit in Idaho...

is dusted with the first snow of the season on a stormy afternoon. A violent 6.9 magnitude earthquake occurred in the Lost River Range on 28 October 2983 and created a 21 mile (34 km) long fault scarp at the foot of the mountain front.

Borah Peak (12,662 ft (3,859 m)). Note the prominent fault scarps at the foot of the lowermost slopes created during the 1983 earthquake.

US Forest Service interpretive site along a fault segment created during the 1983 event. Borah Peak is at the center skyline.

My 8th grade earth science teacher...

stoked my early interest in geology and, next to my parents, Ellis Underkoffler is clearly the most pivotal person in my early formative life. Here we are, now years later, at a regional meeting of the National Association of Geoscience Teachers, Ellis having invited me to deliver the keynote address at the conference highlighting my adventurous cave research in Central America. It was a fun reunion. Inspiring teachers are important!

This living fossil...

first appears in the rock record about the time of the dinosaurs - Early Jurassic (201.3 - 174.7 Ma) - and it persists on the landscape today and is known by a variety of common names.

Horsetail (genus Equisetum).

The angle of repose of wheat...

is about 27 degrees to the horizontal as demonstrated by these piles of grain outside an elevator. This critical threshold describes the maximum stable slope that a dry, loose granular material can assume and is primarily a function of the grain size of the material involved. This concept is employed by geologists when assessing the stability of natural slopes.

Grain elevator near Ritzville, Washington. It’s been quite a good yield despite the dry conditions this year in the Columbia Basin.

Enigmatic natural mounds of soil and sediment...

dimple the eastern Washington landscape, so-called Mima mounds, where geologists have proposed multiple hypotheses in order to explain their puzzling origin. They seem to be relic features not being formed today, so I favor the periglacial origin, similar to the mechanism that creates patterned ground in Arctic regions.

Wide view of Mima mounds in Turnbull National Wildlife Refuge. Click on image to embiggen.

The low areas between the mounds often contain vernal pools of shallow water in late winter and early spring. Click on image to enlarginate.

Three tree molds ensconced in basalt...

bedrock occur along the Fish Lake trail, the result of an advancing lava flow into a standing forest during the Miocene Epoch. Imagine the snap, crackle, pop and hiss as the trees were overrun by the molten lava. Geology is everywhere, you just have to look!

Old railroad cut exposing a tree mold in the Wanapum Basalt, Priest Rapids Member (15.97-11.63Ma).

Base of another tree mold showing the flaring of the root collar in contact with the underlying paleosol. Note the silicified wood fragments that still exhibit cellular structure.

The strongly-jointed Humbug Spires...

near Butte, Montana offer a myriad of easy to moderate rock climbing routes on a smooth, spheroidally weathered granite.

Quartz monzonite of Cretaceous age (145-66 Ma) that comprises the Boulder batholith south of Butte, Montana. Orthoclase and plagioclase feldspars and quartz are the lighter minerals with accessory biotite and hornblende constituting the dark minerals.

This cobbly terrace edge remains stable...

after the dry winter and spring, with no evidence of any unraveling or failure whatsoever along the length of the escarpment. Castle Creek, slightly off the image to the right, is not likely to undercut this sedimentary terrace anytime soon. The singletrack remains safe to cruise.

The guts of the Moab Fault...

exposed for all to see near the entrance to Arches National Park, just above the Visitors Center. A chunk of the Moenkopi Formation is trapped in the brecciated zone in between a pair of extensional faults (yellow lines). More than a half-mile of vertical displacement has occurred across this zone, that is, the Entrada Sandstone lies considerably higher in the stratigraphic section than the Honaker Trail Formation, so the relative offset is UP on the left and DOWN on the right across the fault zone in the view seen below.

View is towards the northwest. Note the tour bus on the park road on the right side of image. Yellow lines are normal faults with downthrown blocks on the right side of each.