A gang of five painted faces...

is hidden in a sandstone alcove protected from the elements, thereby preserving the vibrance of the pictographs, in upper Davis Canyon inside the boundary to Canyonlands National Park. They seem a jovial bunch.

The wonderful Five Faces pictograph panel in Davis Canyon and another guy.

Log House ruin in Davis Canyon sits high on a ledge, precluding any close investigation. Note the numerous hand prints above the structures. All of the wooden logs had to be lifted up the cliff face!

Conjuring spirits the night before our walk, BH contemplates the meaning of life, the universe and everything at our rock shelter camp.

An interesting alignment of glyphs...

occurs in Shay Canyon where two separate but identical geometric patterns, about 20 feet (6 m) from one another, seem to match from the right perspective as one approaches the petroglyph panel from below. Coincidence or purposeful design by the ancient scribe?

Friend and neighbor BH points along the sight line that links the two separated petroglyphs.

BH’s point of view as observed from his position in the first image.

Did ancient astronomers use the Six Shooter Peaks...

as natural pointers in order to track the changes in seasons? Here are a couple of potential “observatory” sites that the early residents of Indian Creek Canyon constructed along sight lines related to equinox and solstice sunrises and sunsets.

The so-called “Mushroom Ruins.”

The “Boulder House.” The summit of South Six Shooter Peak sure looks like a gunsight from this perspective.

Photographer’s Ephemeris software suggests that the Boulder House ruin is optimally located to catch the descending Sun in the notch of South Six Shooter Peak during the winter solstice. An early winter test of this hypothesis is in order if the weather permits.

Red pin is location of Boulder House. Yellow line marks the Sun’s position, blue line marks the Moon during winter solstice.

Sun’s position at 3:34 pm MST on 21 December 2026, during winter solstice. Note the sharp shadow cast by the spire pointing directly at the location of Boulder House.

But wait, there’s more: Boulder House ruin also has a direct sight line to the summit of North Six Shooter Peak, and during the summer solstice the setting Sun falls right above its summit! This is no accident but by design.

Boulder House ruin and the view toward North Six Shooter Peak.

Photographer’s Ephemeris shows that during the summer solstice the Sun passes over North Six Shooter Peak during sunset, as seen from Boulder House.

Silent witnesses to the placement...

of an important historical survey monument, these so-called ‘witness marks’ were chiseled into this basalt rock outcrop years ago as an aid to future surveyors in order to locate or ‘recover’ the old monument. Distances and bearings from these markings to the monument were recorded, and where they intersect, voila. These two glyphs were just recently touched up with a Sharpie by Washington State Department of Transportation engineers doing fieldwork along the bike trail, attempting to recover the monument marking the section corner.

The guided tour of Boundary Dam...

on the Pend Oreille River at the US-Canadian border, a concrete arch-gravity dam constructed in 1967 for hydroelectric generation, was nothing short of excellent. A big thank you goes to the engineers from Seattle City Light that owns and operates the structure for a terrific exploration of the facility.

View due north, down river and into Canada from the top of the arch dam, 338 feet (103 m) above the water surface.

View of Boundary Dam from river level, with the six transformer stations on the right where high voltage power lines exit the underground powerhouse.

Service tunnel entrance to the subterranean powerhouse, including the generator hall, transformer stations, the control room for operation of the structure and administrative offices.

Generator Hall, an enormous chamber excavated out of limestone bedrock, showing six turbines with one undergoing refurbishment.

An enormous diluvial dumping...

from pluvial Lake Bonneville occurred through this gap in southeastern Idaho known as Red Rock Pass. The volume of the great gush is estimated at five thousand cubic kilometers (1,200 cubic miles!) of water, released about 14,000 years ago in a catastrophic megaflood that likely lasted weeks to months and scoured the Snake River Plain in Idaho downstream from this site.

Red Rock Pass, a few miles south of Downey, Idaho on US 91. View is to the south, or upstream during the big spill. The vast expanse of Lake Bonneville would have existed on the far side of the skyline ridge, reaching across a third of Utah. Once the rising lake water began spilling across this low point along its shoreline and into the adjacent valley, a great unraveling was unleashed. The unconsolidated surficial alluvium and the underlying sedimentary rocks forming the bedrock sill rapidly eroded, much as a dam collapses when overtopped.

Red X marks the spot (near lower right) of Red Rock Pass, the spillover point for Lake Bonneville. The torrent of floodwater exiting the basin through the gap lowered the overall lake level approximately 105 m (350 feet). Map from Idaho State University.

More here about this tremendous flood from the Idaho State University: Lake Bonneville flood.

Happy 250 America...

as Castle Valley celebrates the semiquincentennial anniversary of the founding of our great nation on this Independence Day. Community tradition has the volunteer members of the Castle Valley Fire Department hosting a breakfast and parade, seen here featuring Engine 37 leading the way.

Cherry on top: Air quality this morning is the best since the summer solstice.

Read the Declaration of Independence.

The lower Dolores River canyon...

a few miles above its confluence with the Colorado River, as seen from Gold Mine Road on an early morning drive.

Note the disturbance on the lower slopes across the river, left of center, the site of a historic placer gold mining operation.

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.

The "hanging flume" is a marvel of engineering...

in the San Miguel and Dolores River canyons, built between 1888 and 1891 by very determined miners working a gold placer deposit further up the canyon. Imagine trying to build this incredible project today!

Remains of the five mile-long wooden flume above the San Miguel River, still clinging to the sandstone cliff after more than 130 years.

Closer view of a section of the wooden flume as seen from an overlook from above, on Colorado 141 north of the former townsite of Uravan.

View from below at a partially restored section of the historic flume. The flume only operated several years after its completion, following which the wooden beams and planks were scavenged and re-purposed for other uses.

Around the nose of a meander bend, the hanging flume hugs the escarpment above the San Miguel River, a short distance above its confluence with the Dolores River.

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).

Viewing pictographs under different wavelengths...

of light reveals hidden details not seen by the naked eye when observing rock art under the visible part of the spectrum. Here are three pairs of comparative images of several sections of the wonderful pictograph panel in Buckhorn Wash in the San Rafael Swell, a small portion of which is seen below.

The following pairs of images first show an unretouched raw image followed by an enhancement filter applied by DStretch software.

The software is available at DStretch.com.

An interesting discovery along Castle Creek...

by an archeological survey crew, excitedly shared with me yesterday, only a short distance off a singletrack that I frequently ride. Cool beans.

Boulder mortar or bedrock metate on a sandstone slab.

Note the fine detail on inner surface showing linear striations consistent with wear marks created by a back-and-forth grinding motion.

Breaking in the brand new Bronco...

on the Dome Plateau today. Please excuse the Bronco porn that follows but this is its first time off road since being assembled only 28 days ago in Michigan.

Expansive view towards the south from a high point along the trail.

So-called “Cave Spring” in the Entrada Sandstone escarpment, used historically by ranchers to provide water to stock.

Relict uranium miner’s cabin on Owl Draw Upland.

The new manual Ford Bronco Badlands/Sasquatch is an enormously capable machine that will open up more areas in the backcountry for exploration. What’s a retired geologist to do when not mountain biking or launching rockets?!