Devil’s Slide and A Jumping Fox

Devil’s Slide, a part of Cinnabar Mountain, is located about 3 miles north of Yellowstone National Park’s northern boundary and about 7 miles northwest of Gardiner, Montana. The “slide” or red streak on Cinnabar Mountain is developed in Triassic red beds.

Whenever I drive to Yellowstone National Park’s northern gate, I pass by the Devil’s Slide. It seems that the slide is my gate keeper to the park, and it is always fun to see it in all our different seasons. And once again, during a chance conversation in the park, I was asked about the geology of Devil’s Slide. Because of that conversation, I thought that I’d spend some time blogging about the slide’s geology.

Devil’s Slide is a part of Cinnabar Mountain, which contains steeply-dipping to overturned Paleozoic and Mesozoic strata. Cinnabar Mountain is fault-bounded on its north side by the Gardiner Fault, a north to northeast dipping reverse fault zone. At Cinnabar Mountain’s north end, the Gardiner Fault juxtaposes Archean crystalline rock (now partly masked by Tertiary intrusive rocks and Quaternary glacial sediments as shown on geologic map snapshot below) on the fault’s northern, up-thrown side against Paleozoic strata on its down-thrown, southern side. The Paleozoic-Mesozoic strata in Cinnabar Mountain are contorted because of drag associated with the Gardiner Fault.

Cinnabar Mountain and Devil’s Slide area as a snapshot from the Geologic Map of the Gardiner 30’x60′ Quadrangle, South-Central Montana (Berg and others, 1999, Montana Bureau of Mines and Geology Open-File Report 387). Map symbols on Cinnabar Mountain are: Mm = Mississippian Madison Group, PMs = Permian-Mississippian rocks, Psh = Permian Shedhorn Sandstone, JTrs = Jurassic-Triassic rocks, Kk = Lower Cretaceous Kootenai Formation, Kmfr = Upper and Lower Cretaceous Mowry Shale through Fall River Sandstone.

According to Marius Campbell and others (1915, p. 92), “Cinnabar Mountain was named in the early days, when the bright-red streak that marks it from top to bottom was supposed to be due to the mineral cinnabar, a red ore of mercury.” (From: Guidebook of the Western United States: Part A – The Northern Pacific Route, With a Side Trip to Yellowstone Park, U.S. Geological Survey Bulletin 611). We now know that the bright red streak is not cinnabar (a brick-red form of mercury sulfide), but the area of red in Devil’s Slide is actually a set of Triassic age red beds that mark widespread continental deposition and limited marine incursions throughout the Rocky Mountain region. The red beds in this case get their color from the oxidation of iron-rich minerals contained within the rocks.

And now for the jumping fox and its association to my Devil’s Slide discussion – as I said previously in this blog, the conversation that I had with a fellow-park goer a few days ago brought about my blog on Devil’s Slide. My conversation about the slide happened while I was watching a fox hunt rodents in YNP’s Round Prairie, a gorgeous meadow near Pebble Creek Campground in the park’s northeastern area. The female fox hunted for hours that morning, and several photographers and myself were enthralled with her hunt. The light snowfall of the night before accentuated the bushy fall coat of the fox and gave the hunting scene great color contrast. Here are are few photos from the hunt:

Round Prairie fox with her gorgeous fall-winter coat.
Round Prairie fox on the hunt.
Round Prairie fox on her hunting jump.
Round Prairie fox finishing her hunting jump.

Yellowstone To Southwest Montana Autumn Field Photo Snaps

Montana’s autumn is my favorite time of the year to do field work. Daytime temperatures are usually cool enough to encourage one to keep moving and the lighting is simply gorgeous. It is also one of the best times to visit areas in and around Yellowstone National Park (YNP) because most of the tourists have gone home. So no huge bear traffic jams or jostling for parking spots at the better known thermal spots in YNP and surrounding environs – it’s just a wonderfully introspective time for field forays. What follows are several photos that chronicle some of my fall wanderings in the greater Yellowstone area, both in terms of wildlife and geology.

Some of my favorite sightings in YNP are bison at any time of the year. But the autumn snows bring on the bison’s technique of using its head to clear snow away from any vegetative food source. The result of their snow-clearing activity is a snow-masked face.

Snow-caked face of a bison in YNP portends the winter food retrieval.

Snow-masked bison near Soda Butte Creek, YNP.

And where the snow hasn’t stacked up much, the YNP bison calmly graze and occasionally congregate on a ridge line to watch what remains of the YNP visitor traffic.

YNP bison contemplating passing vehicles.

Geological features in YNP take on new dimensions with the golden low and slanting light of autumn. I’ve spent much time re-photographing geologic features at all scales that seem to glow in this season’s light.

Tertiary sediments and Quaternary sediments/basalts of “The Narrows” cliff face adjacent to the Yellowstone River, northern YNP. Columnar basalt capped by auto-brecciated basalt makes a morel-like image for these geological units.

An early morning at -7 F on the Lamar River with steam fog resulting from the fall’s chilled air moving over water still warmed from summer.

A rodent trackway disappears into microterracettes of Palette Springs, Mammoth Hot Springs, YNP.

Microbial growth near the proximal part of Mound Springs, Mammoth Hot Springs, YNP.

The proximal end of Mound Springs abounds in various colored microbial life. It’s hard to stop photographing these features because they are so intriguing!

The lipped margin of Mound Spring’s pond facies, Mammoth Hot Springs, YNP.

The fall staging areas of sandhill cranes in southwestern Montana are mesmerizing. Staging areas are those locations where cranes annually congregate during late September into October, spend several days foraging through fields for food, and eventually continue on their migration southward from Montana to Colorado and the southwestern U.S.. The staging area that I usually go to is near Dillon, Montana, where hundreds of cranes can be viewed.

Sandhill crane interaction during their fall staging near Dillon, Montana.

Sandhill cranes doing a dance routine in the Dillon, Montana staging area.

As I said initially, it’s hard to surpass a Montana/YNP autumn!

Greater Yellowstone Area Eocene to Recent Hydrothermal Springs

The Gravelly Range spring deposits depicted in this photo are late Eocene (probably 34-36 million years in age).

Geologic field work is always fun, but especially so when it turns up something unexpected. Working on Eocene to Recent geology and vertebrate paleontology in the Gravelly Range, southwestern Montana promised to be enthralling because the volcanics, sedimentary units, and vertebrate fossils are at elevations of about 9,000 feet. But to come across extensive, unmapped calcareous spring deposits of probable Eocene age is topping off research efforts.

At this point, I’ll just say that our field team is still at work on the Tertiary spring deposits. We’ve found numerous leaf impressions including those of ginkgo, palm, metasequoia, Fagopsis (extinct member of Beech family), and alder – just to name a few. We’ve shown the plant assemblage collected to date to several paleobotanists, and, at least for age, their take is that the assemblage is probably latest Eocene in age, and bears many similarities to Florissant, Colorado fossil plant assemblages.

Palm frond impression from Gravelly Range spring deposit.

Ginkgo leaf impression from a Gravelly Range spring deposit.

Alnus cone from a Gravelly Range Spring deposit.

The spring deposits in the Gravelly Range are extensive, covering an area roughly 2 miles in length with deposits up to 120 feet in thickness. The springs are best characterized as travertine, although the spring systems’ edges contain clastic fluvial units and both the springs’ edges and pools have features such as plant impressions, root systems, and small travertine balls.

Gravelly Range Eocene spring deposit. Field backpacks in lower left corner for scale.

Because the Gravelly Range is so close to Yellowstone National Park, it is extremely interesting to compare its Eocene spring deposits to hydrothermal units at both the currently active Mammoth Hot Springs (which probably began its activity about 7,700 years ago), and to the fossil travertine found just north of Gardiner, Montana, that formed about 19.500 to 38,700 years ago (Fouke and Murphy, 2016: The Art of Yellowstone Science: Mammoth Hot Springs as a Window on the Universe).

The Gardiner travertine is fairly well exposed because it has been extensively quarried for several decades. Of interest for comparison are numerous plant impressions that occur within microterracettes. Fouke and Murphy (2016) suggest that these may be impressions of sage brush. A photo of the quarried wall with the plant impressions is shown below.

Plant impressions in Gardiner travertine. These impressions may be from sage brush. The travertine in this quarry face is estimated at about 30,000 years in age.

Other features in the Gardiner travertine, now partly covered by graffiti, include a quarry wall that shows terracettes and microterracettes that are outlined by darker lines within the travertine. These features are probably indicative of a proximal slope facies.

Gardiner travertine with its slope facies depicted well in smooth quarry face. The dark, irregular lines delineate terracettes and microterracettes.

Jumping forward in time to the extensive spring deposits of Mammoth Hot Springs (just within the northeast park boundary of Yellowstone National Park), is mind boggling. As in any comparison with rocks as old as Eocene to active deposition, one realizes how much detail is lost over time. But it is still worthwhile to try to compare spring features, so I’ll show a few photos of the Mammoth Hot Springs that may match up with various features of the fossil springs.

Branch and plant fragments in the process of becoming calcified at Mammoth Hot Springs – main terrace.

Calcified plant debris – Mammoth main terrace.

Terracettes – Mammoth main terrace, proximal slope facies.

Trees engulfed by prograding spring activity – Mammoth main terrace.

Travertine balls in small pond – Mammoth main terrace.

Suffice it to say, that the upcoming field season should be a good one, with more work to be done on the Gravelly Range spring deposits. And – it’s always fun to get a trip in to Yellowstone!

Winter Trekking Through Yellowstone’s Thermal and Glacial Features

Cross country skiing in one of the glacial melt-water channels on the Blacktail Plateau.

Some winter days in Yellowstone National Park are so amazing with clear blue skies and sparkling snow that they just take your breathe away. Luckily enough, I just experienced several of these kinds of days which I packed full of cross country skiing, snowshoeing, and animal watching.

One of the groomed trails that held a good snow base until about early afternoon is the Blacktail Plateau Loop. The trail follows melt-water channels that are associated with “Retreat Lake”, which was formed by the Beartooth glacial ice mass blocking the lower end of the Grand Canyon of the Yellowstone during the Pleistocene.

Rounded cobbles and boulders left behind from melt-water flow sit on the volcanic bedrock in many areas along the trail. Ski tip in the lower right for scale.

Looking back to the northwest on the Blacktail Plateau ski trail. Notice the scoop-shape of the landscape which is the result of this area being part of a glacial melt-water channel.

Calcite Springs overlook is accessible during the winter via the Tower ski trail.

The Tower ski trail provides access to the Grand Canyon of the Yellowstone area. A favorite stop of mine is the Calcite Springs overlook where the thermal springs lie south of the overlook, on the west side of the Yellowstone River and Pliocene/Pleistocene sediment and basalt are on the Yellowstone River’s east side.

 

A groomed ski trail also accesses the Upper Terraces of Mammoth Hot Springs. However, after a few days of spring-like temperatures, the snow was so melted back that I just used my snowshoes to trek through the icy slush.  Some thermal features were still covered by snow and slush, but others appeared much more vibrant against the white snow/slush blanket.

One of the fissure ridges along the upper Terraces trail is called White Elephant Back Springs and Terrace.

Aphrodite Terraces lie a short way north of the White Elephant Back Springs:

My favorite thermal feature of the Upper Terraces is Orange Spring Mound. The spring is supported by a fissure ridge and is intermittently active. Because of its low water discharge and subsequent slow growth, it has built up a characteristic cone shape.

Orange Spring Mound of the Upper Terraces in Mammoth Hot Springs.

All in all, it was perfect wintertime fun trekking around in Yellowstone. Can’t wait to get back there when the bears come back out from hibernation!