is exposed in the strike valley below Castleton Tower, seen below in this geologically annotated image that includes the formation names and ages (Ma = mega annum = millions of years). The tilted beds of the Cutler Formation (right) comprise the northeastern limb of the Castle Valley salt anticline.
View toward the southeast with Adobe Mesa in the distance. (Click on image to expandify.)
Yes, it was another terrific afternoon for a bike ride in Castle Valley National Park.
were certainly moving as bedload in this ephemeral wash below Adobe Mesa during the flash flooding events this summer. Here they now sit, shingled on top of one another, likely stranded for a decade or more until mobilized in the next extreme hydrologic event in this drainage.
As artificial as the sky and cloudscape appears in this image, it was that lovely of a day in Castle Valley.
occurred above the bridge on Castleton Road during this summer’s flooding, clearly evident from examining these images taken three years apart. Compare and contrast.
THEN: Castle Creek on 17 November 2021.
NOW: Castle Creek on 31 October 2024.
throughout Castle Valley is clearly seen in the recently updated satellite imagery available in Google Earth and Google Maps. Light-colored sedimentary deposits paint the areas affected by overland sheet-flooding and where floodwaters escaped ditches and natural channels. Compare and contrast.
Imagery date: 7 August 2024.
Imagery date: 14 October 2022.
Hint: Learn to use the time slider tool in Google Earth to time travel into the past and examine earlier satellite imagery.
occur in the Wanapum Basalt Formation (Columbia River Basalt Group) along the Fish Lake Trail, exposed in a railroad cut through the volcanic formation within 100 yards (meters) of one another. One can easily imagine a landscape with a stand of large trees being invaded and enveloped by an advancing lava flow around 15 million years ago. I’m certain that 99% of the trail users aren’t aware of these interesting features and the story they tell.
Note the silicified wood that is preserved near the base of this large tree mold.
This tree mold is about 20 inches (0.5 meters) in diameter.
The underlying paleosol (ancient soil horizon) in which the tree were rooted is clearly seen here beneath the overlying basalt formation. This tree mold is about 15 inches (0.4 meters) in diameter and penetrates the interior of the volcanic unit.
southwest of Spokane, Washington, the Columbia Plateau State Park Trail extends for 130 miles (209 km) across the semi-arid Channeled Scablands. Some portion of this trail system is part of my daily ride, usually a section between Spokane and Amber Lake, at its very northeastern end.
Open ponderosa pine forests and seasonal wetland ponds dominate the flat-lying terrain that traverses the 1908 path of the Spokane, Portland and Seattle Railroad.
A typical crowded day on the trail.
met for lunch at our favorite Mexican restaurant last week. Emeritus Professor Ernest Gilmour (below left) was the chair of the department when I was hired as a fledgling assistant professor in the summer of 1984, a full 40 years ago, and he remains a good friend and valued colleague. We’re both retired from the university today, but he’s still doing active research in paleontology and publishing on bryozoans. It’s a scientific fact that fossilization is delayed if one stays active, both mentally and physically!
occurs below Bruin Point, Utah in the Green River Formation (Eocene) due to canyon erosion, thereby allowing the volatile compounds to freely migrate to the surface with only bitumen remaining in the sandstone.
View toward the west from Bruin Point, Utah (10,131 feet (3,088 meters)) into Water Canyon. The access road is exceptionally steep and requires a high clearance vehicle.
Block of asphaltic sandstone from the Green River Formation that was quarried below Bruin Point in the early 1800s.
Gravity-powered aerial tramway relic below Bruin Point, circa 1920s.
Here’s a link for geo-nerds: Sunnyside bitumen-impregnated sandstone reservoirs at Bruin Point, southwest Uinta Basin, Utah.
is the site of one of the largest volcanic eruptions in Earth’s history approximately 28 million years ago (Eocene). That enormous geologic event has left quite a bruise on south central Colorado and also created rich mineral deposits in the region.
Oblique aerial view towards the north showing the 20 mile wide (32 km) La Garita Caldera structure from Google Earth. Snowshoe Mountain is a resurgent dome in the core of the caldera.
The upper Rio Grande Valley on the western side of the La Garita caldera.
Much of the valley bottom is mantled with glacial till in terminal and lateral moraines and with glacial outwash.
Bristol Head mountain stands at 12,712 feet (3,875 meters) high with a smaller resurgent dome on the left.
Caldera-filling sedimentary rocks of the Creede Formation (Oligocene) near Creede, Colorado reflecting a lacustrine environment of deposition.
superimposed on mudcracks in fine-grained sediments. The preservation potential for these tiny sedimentary structures in the geologic record is not high, but their delicate nature makes them interesting to examine.
Average craterlet size is approximately 0.25 inches (~6 mm) in diameter.
of the steep gradient, coarse-grained and ephemeral Placer Creek channel through time, coupled with headcutting by knickpoint migration through the stream crossing, has created a challenge in upper Castle Valley for road maintenance. Compare and contrast the conditions that existed five years ago and today.
Placer Creek crossing on 1 May 2019. Note crushed culvert and concrete on downstream side of roadway. By attempting to maintain this knickpoint in the stream profile for the long term only exacerbated the erosion that eventually occurred here.
Placer Creek crossing on 30 June 2024. Significant scour has deepened the channel once again. The knickpoint has migrated upstream and behind the two large boulders on the left.
The road crossing is now graded to a more stable position in the short term, at the same elevation of the stream channel both upstream and downstream, now that the knickpoint has migrated upstream and no longer occurs right at the crossing as seen in the early image.
View upstream showing the knickpoint in the stream channel that will continually erode upstream with future events.
during the last several days, muddy deposits left behind on the landscape by the recent flash floods have become hard-baked by high temperatures. Desiccation structures - mudcracks - have developed on the fine-grained sediments.
on display in the canyons, washes and arroyos in mid- to upper-Castle Valley as a result of an intense thunderstorm two days ago. Erosion and sedimentation has occurred across a widespread area - both in and out of channels - but no structural damage was observed anywhere.
in the eponymously named bird, with now more than a dozen individuals pecking around the feeding stations. Gorgeous but tiny birds in the Cardinal family.
Lazuli Bunting (Passerina amoena).
Link to the mineral lapis lazuli.
Note to self: These images would be better if I cleaned the windows.
UPDATE 2 May 2024: Here’s an image, caught in direct sunlight, through clean windows.
with minimal paleontological interpretation, future visitors to Utahraptor State Park are likely to be somewhat disappointed. The local chapter of the Utah Friends of Paleontology hosted a presentation delivered by park manager Joshua Hansen this evening where he provided some details on the new park being developed north of Moab.
I’ve requested that this diagram be posted on-line so that the public can understand the development plan. One will still be allowed to travel Willow Springs Road and Dalton Wells Road without paying an entrance fee.
for aerial observation of landforms. And remember, geologists always get window seats (except on a Boeing 737 Max 9).
Mancos Shale badlands near Grand Junction, Colorado. The overlying Mesa Verde Group (Cretaceous) crops out in the escarpment.
View towards the northwest. La Sal Mountains and Paradox Valley (a collapsed salt-cored anticline).
Grand Canyon and Colorado River.
and sitting patiently for millennia, this pair of 1.5+ meter diameter sandstone boulders lie on an old alluvial fan surface below Round Mountain. These enormous clasts were likely entrained in a viscous slurry of water and sediment that moved down the steep topographic gradient, perhaps mobilized by an intense rainfall event, countless centuries ago.
And it was a beautiful - but blustery - day for a ride.
resembling a cinder cone, Round Mountain is most certainly NOT volcanic in origin. It does indeed consist of igneous rock, but in an intrusive body that cooled and crystallized while still under the cover of sedimentary strata, now being exposed by the subsidence of the Castle Valley salt-cored anticline and through erosion.
Hand specimen of the trachyte porphyry found in Round Mountain. Note the large, white crystals of sanidine feldspar, evidence of its igneous origin.
Oh, yeah, it was a very nice afternoon for a ride.
mountain bike trail near Castle Creek, where a seasonal unravelling of matrix-supported gravels had failed from the edge of a high fluvial terrace. May have to modify a short section of the trail this coming spring.
