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!

 

Tertiary Paleovalleys in the Laramie Mountains, Wyoming

The Laramie Mountains are part of the central Rocky Mountains in southeastern Wyoming. Archean and Proterozoic rocks form the bulk of the mountain range due to late Cretaceous–early Eocene (Laramide) basement-involved uplift. Hogbacks made of Paleozoic to Mesozoic age rocks flank much of the

The Laramie Mountains of southeastern Wyoming contain Proterozoic and Archean rocks that are now exposed by a late Cretaceous –early Eocene (Laramide) basement-involved uplift.
The Laramie Mountains of southeastern Wyoming contain Proterozoic and Archean rocks that are now exposed by a late Cretaceous–early Eocene (Laramide) basement-involved uplift. The Precambrian rocks are flanked by hogbacks of Paleozoic to Mesozoic age rocks as seen in the above photo.

Precambrian cored mountain areas. But what sets the Laramie Mountains apart from the adjoining Colorado Front Range and even the western Great Plains is that upper Eocene to Miocene strata are preserved within the Laramie Mountains and on its sides as paleovalley fill. The reasons for this unusual paleovalley fill preservation can probably be tied to the Laramie Mountains being much lower in elevation than the adjoining Colorado Front Range and that they were not glaciated during the Pleistocene.

I went on a field trip a few days ago specifically to look at the Laramie Mountains Tertiary paleovalleys. It was a really good trip. Emmett Evanoff led the trip and because he’s spent so much time working in the area, he had much info and insight on the paleovalleys. What follows are a few photos from the trip:

High Plains escarpment of Tertiary rocks on the eastern flank of the Laramie Mountains near Chugwater Creek. Eocene White River mudstone and siltstone, beds are capped by coarse sandstone beds. An overlying gravelly sandstone unit, probably of the upper Oligocene Arikaree Formation lies above the White River beds. The Miocene Ogallala Formation of stacked conglomerate sheets caps the entire section.
High Plains escarpment of Tertiary rocks on the eastern flank of the Laramie Mountains near Chugwater Creek. Eocene White River mudstone and siltstone beds are capped by coarse sandstone beds. An overlying gravelly sandstone unit, probably of the upper Oligocene Arikaree Formation lies above the White River beds. The Miocene Ogallala Formation containing stacked conglomerate sheets caps the entire section.
The walls to the Tertiary paleovalleys near Chugwater Creek are hogbacks of overturned rocks ranging from Pennsylvanian to Cretaceous in age.
The walls to the Tertiary paleovalleys near Chugwater Creek are hogbacks of overturned rocks ranging in age from Pennsylvanian to Cretaceous.
Daemonelix burrow in Arikareean strata. The burrow is a corkscrew shaped burrow made by the ground beaver Palaeocastor.
We found a Daemonelix burrow in Arikareean strata. The burrow is corkscrew shaped and was probably made by the ground beaver Palaeocastor.
foodtruck
Pat’s food truck was a welcome sight during the field trip. As she said – good food and good rocks – what’s better than that?

 

Large boulders occur at the base of White River Formation in the Toltec Tertiary paleovalley. The Toltec paleovalley is on the west side of the Laramie Mountains where basal Tertiary strata are exposed at and close to the range margins.
Large boulders occur at the base of the White River Formation in the Toltec Tertiary paleovalley. The Toltec paleovalley is on the west side of the Laramie Mountains where basal Tertiary strata are exposed at and close to the range margins.
Polished boulders of Precambrian granite are found in the Garrett paleovalley which now lies in the drainage area of the North Laramie River. Wyoming is known for wind and these boulders certainly attest to that.
Polished boulders of Precambrian granite are found in the Garrett paleovalley which now lies in the drainage area of the North Laramie River. Wyoming is well known for wind and these boulders certainly attest to that.

 

 

 

Yellowstone’s Firehole Lake Drive Reopens

Last Thursday (July 10),Yellowstone National Park (YNP) temporarily closed the 3.3 mile-long Firehole Lake Drive, a paved road that traverses some of Lower Geyser Basin. Melting asphalt on a part of the road near the start of the loop drive became a “soupy mess”, according to Dan Hottle, YNP spokesman. Hottle told Live Science that Firehole Lake Drive’s surface reached 160° Fahrenheit (70° Celsius) on Thursday, roughly 30° to 40° F (17° to 22° C) hotter than usual. Hot gases from area thermal activity that were trapped by the asphalt road surface and warm weather combined to cause the road damage.

YNP said that the road would reopen soon and sure enough, by the time I was there on Monday (July 14), the road was driveable. One of the YNP information rangers at Canyon Village told me that the road repairs included road crews removing damaged pavement and applying a mixture of sand and lime to soak up some of the thick bubbly road oil.  The road section was then graveled so that the hot gases could better escape a more permeable road surface.

I drove over a part of the Fire Hole Lake Drive that was repaired due to melted asphalt last Sunday, soon after the road was reopened.  The damaged road section is now graveled. Note the absence of steam rising from the road surface - even though it was cool and rainy that day.
I drove Firehole Lake Drive loop last Monday, shortly after it was reopened, and stopped to photograph some of the damaged road. The section of the road that contained the melting asphalt is now graveled, and judging by the absence of steam rising off the road (the day was cool and rainy, so I expected to see some steam billowing above the road surface), it looks like the YNP road fix is working.

Thermal activity affecting YNP roads and parking areas is not uncommon. During my Monday travels in Yellowstone, another Canyon area YNP ranger told me that about 10 years ago, a new thermal feature melted a small part of the Mud Volcano parking lot. This area is now fenced off, but the rest of the parking lot is still used. YNP spokesman Hottle also informed Live Science that YNP has closed Firehole Lake Drive in the past for repairs due to heat damage, but that these closures are not frequent.

A small part of the parking lot at Mud Volcano fell victim to thermal activity several years ago.
A small part of the parking lot at Mud Volcano fell victim to thermal activity several years ago.

And – just for some perspective on this latest road meltdown: the YNP website home page says “Yellowstone contains approximately one-half of the world’s hydrothermal features. There are over 10,000 hydrothermal features, including over 300 geysers, in the park”. Given the profusion of thermal activity, I’m not surprised that a small section of asphalt melts once in a while. I guess I’m amazed that the YNP can keep park infrastructure maintained such that millions of people can visit the park every year.