Hiking to Glacier National Park’s Grinnell Glacier

A few days ago I did the hike to Grinnell Glacier, one of the iconic glaciers in Glacier National Park. The glacier lies within the Swiftcurrent drainage area, in the northeastern part of the park. The hike, at least the way I did it, is about 11.6 miles round trip. It is possible to catch a boat ride at the Lake Josephine Boat Dock by the Many Glacier Hotel, which cuts the hike down to about 7.5 miles round trip. But – the first boat goes out at about 8.30 am, and as I didn’t want to wait around for it, I decided that adding on the extra miles for a fairly level stretch around Swiftcurrent Lake and Josephine Lake would be easy to do. It is an easy hike around the lakes and a very good warm-up for the rest of the climb to Grinnell Glacier. But –  be aware that this area is known for grizzly bear activity as I found out when I met up with a grizzly on the trail. Because I’m writing about this encounter,  it obviously ended OK, although I was glad I had bear spray readily available.

The glacier is named after George Bird Grinnell, who first explored this area during the summer of 1885. Because of bad weather, he did not actually get to the glacier during his 1885 travels. However, during the late fall of 1887, he was able to pack most of the way into the glacier by mules, and then hike the remaining distance by foot.  Although he certainly was not the first person to see the glacier, the glacier does bear his name, presumably given it by a Lieutenant John H. Beacom of the United States Army, 3rd Infantry, who accompanied him on the 1887 trip to the glacier.

It’s fun to see ripple marks in the Proterozoic rocks that outcrop along the Grinnell Glacier trail (Grinnell Lake is in the photo’s background).

Back to the hike – after about a mile from the junction of the Swiftcurrent Lake Trail with the trail coming from the North Shore of Lake Josephine boat dock, Grinnell Lake comes into view. A little further along the trail one can see Grinnell Falls dropping several hundred feet down from the headwall behind Grinnell Lake.

Grinnell Falls drops several hundred feet down from the headwall to Grinnell Lake. The Salamander Glacier can be seen in the photo’s upper right-hand corner; Gem Glacier is in the upper left-hand corner of the photo.

And – even at this distance, Salamander and Gem glaciers pop into view in the distant cirque. The hike continues along beautiful alpine meadows and even through one waterfall that cascades down the cliff adjacent to the trail. There is a rest area with pit toilets right before hiking the final switchbacks that traverse the terminal moraine to the Grinnell Glacier Overlook.

The final part of the Grinnell Glacier trail traverses the glacier’s terminal moraine.
Large boulder (Elrod’s Rock) in the Grinnell Glacier’s terminal moraine. Note the marmot atop the boulder for scale. The glacier’s terminus is now about a mile away from this boulder.

The three glaciers that once comprised the Grinnell Glacier occupy parts of a cirque developed along the area called the Garden Wall.

The cirque of the Grinnell, Salamander, and Gem glaciers.

Grinnell Glacier is still the largest of the three ice fields and covers about 152 acres. Unfortunately, this glacier is receding rapidly as the U.S.Geological Survey notes that from 1966 to 2005 it lost about 40% of its acreage. At about 5 acres, the hanging glacier called Gem Glacier, is the smallest named glacier in the park. It sits in the notch on the cliff face above the Grinnell Glacier. This glacier lost about 30 percent of its acreage from 1966 to 2005. The Salamander Glacier covers about 57 acres on a ledge off to the east side of the Grinnell Glacier. It apparently separated from the Grinnell Glacier sometime before 1929 and has undergone a 23% size reduction from 1966 to 2005.

For those interested in viewing photographs of the Grinnell Glacier from various times and viewpoints, the U.S. Geological Survey’s Repeat Photography Project has many archived photographs. This project is a documentation of glacial decline through photography and it is well worth perusing through their photo archives. Two of the earlier photographs are shown below – one from the original 1887 trek and a later view of the glacier from 1940 just to pique one’s interest.

1887 photograph of the Grinnell Glacier taken from footbridge (Lieutenant Beacon, Glacier NP. Public domain).
1887 photograph of the Grinnell Glacier taken from footbridge (Lieutenant Beacom, Glacier NP. Public domain).
Grinnell Glacier from trail 1900; Credit: F.E. Matthes, Glacier NP. Public domain.

Tertiary Geology and Paleontology in the Gravelly Range, Southwestern Montana

Lion Mountain in the Gravelly Range of southwestern Montana. This area is federal land managed by the U.S. Forest Service.

A part of my recent geological field work includes working on high elevation Tertiary strata in the Gravelly Range, southwestern Montana. The Gravelly Range is located in southwest Montana, about 10 miles southwest of Ennis, Montana. For some background on this area and what my field work is about, see an older blog that I posted at Geopostings.

So – now that one field season is done and field data compiled, both my co-worker, Don Lofgren and myself have interpreted some of our data. We recently outlined our work at the Geological Society of America’s (GSA) Rocky Mountain section meeting in Calgary. Alberta. The abstract from our session is given below as well as the poster itself in both a jpeg format and as a link to our  GSA presentation.

“Tertiary strata exposed in four high elevation areas in the south-central
Gravelly Range yield significant assemblages of Late Eocene to Oligocene
mammals. The thickest stratigraphic sections of Tertiary strata are in the
Lion Mountain-Black Butte area. The Lion Mountain section age is based
primarily on American Museum of Natural History collections; the lower
part of this section is Duchesnean-Chadronian (39-33 Ma) and the
uppermost beds are Whitneyan (32-31 Ma). Age of the basal part of the
Black Butte section is Duchesnean-Chadronian based on Harvard Museum of Comparative Zoology collections. Recent collections that include Miohippus indicate a probable Orellan age for uppermost exposures. The Tepee Mountain section is notable for abundant brontothere remains and is probably Duchesnean-Chadronian (approx. 39-33 Ma). The Rapamys site is the oldest vertebrate locality and is late Uintan to early Duchesnean (42-38 Ma) based on recently recovered specimens of RapamysProtoreodon, and Lycophocyon.

The Tertiary strata in this part of the Gravelly Range include fluvial, aeolian, and tufa deposits that are most likely mainly associated with localized Oligocene volcanism. The Lion Mountain section is about 270 meters in thickness; the lower half of the section is largely aeolian, with fluvial units comprising much of the upper section. Based upon age data, the 140 meter Black Butte section correlates to the lower 50-70 meters of the Lion Mountain section. The basal 20 meters of the Black Butte section contain some fluvial features, but much of the remaining section is largely aeolian in origin. Paleosols and extensive burrowing also occur within the Black Butte section. Stratigraphic section thickness decreases rapidly away from the Black Butte-Lion Mountain area, with section thicknesses of about 20 meters for the largely aeolian Rapamys and Tepee Mountain sections. Tufa deposits are located along the west-central edge of the Gravelly Range where they are associated with previously mapped thrust faults. Leaf imprint assemblages of Eocene-Miocene age are contained within these tufas. Strata previously mapped as Upper Cretaceous-Paleocene Beaverhead Formation are now variously reassigned to the lower Cretaceous Kootenai Formation, southwestern Montana Cenozoic Sequence 2, and diverse Quaternary units.” From: Abstract from Geological Society of America Abstracts with Programs. Vol. 49, No. 5 doi: 10.1130/abs/2017RM-293156.

The poster presented at the 2017 Rocky Mountain GSA is available below as a jpeg and at GSA as a pdf.

Cenozoic Sequence Stratigraphy of Southwestern Montana

Much of my research has been focused on Cenozoic sequence stratigraphy of continental basin-fill in southwestern Montana. This approach to the stratigraphy of continental deposits has facilitated correlation of stratigraphic units both within and among the various basins of this area. I recently gave a talk about my work in this area at Montana Tech of the University of Montana. Here’s the You Tube version of my talk:

The Field Season Is Going Strong in Southwestern Montana

My field season is in full swing. I recently spent time with students from the Webb Schools in Claremont, CA, during their annual sojourn to southwestern Montana. We prospected a few Tertiary localities, with the students making some good fossil mammal and fossil invertebrate finds. We were also extremely lucky to have a southwest Montana landowner give us a tour of a buffalo jump that is on his land. The following photos are from our various fossil site and buffalo jump field adventures.

woodin-snails
Tertiary fossil snails (about 25 My in age) at one locality captured the interest of students. Once one snail was found, everyone was intent on finding more.
Bob Haseman talks about a buffalo jump in the Toston Valley. He is standing by one of the many tepee rings associated with the jump site.
Bob Haseman talks about a buffalo jump in the Toston Valley of southwestern Montana. He is standing by one of the many tepee rings associated with the jump site. The small boulders on the surface between Bob and the students are part of a tepee ring.
Webb School students hiking up to the "Looking-Out" site associated with the buffalo jump. A eagle catchment area is immediately below the highest point of the "Looking-Out" site.
Webb School students hiked up to the “Looking-Out” site associated with the buffalo jump. A eagle catchment area is immediately below the highest point of the “Looking-Out” site.
eagle-catchment
The eagle catchment area is a shallow depression where a person would hide beneath brush awaiting the approach of an eagle. A nearby animal carcass would aid the quest to capture a eagle which was then used for its feathers.
Chadronian (about 36 Ma) age rocks yielded a few brontothere teeth and bone fragments.
Chadronian (about 36 My in age) rocks near Three Forks, Montana yielded a few brontothere teeth and bone fragments for the curious students.
Chadronian strata in this area contain brown to reddish, popcorn textured floodplain deposits and whitish-colored fine-sand channel deposits.
Chadronian strata in this area consist of brown to reddish popcorn-textured floodplain deposits that contain paleosols and whitish-colored fine-sand channel deposits.

 

 

A High-Elevation Eocene Fossil Vertebrate Site in the Elkhorn Mountains, Southwestern Montana

dogtown1Af
The Dog Town Mine vertebrate fossil locality is an isolated occurrence of Eocene strata found on the divide between the Toston-Townsend Valley (on the east side of the photo)  and the North Boulder Valley (on the western edge of the photo), southwestern Montana.

The Dog Town Mine Tertiary fossil vertebrate locality is nestled on private property within the southern extent of the Elkhorn Mountains, southwestern Montana. The locality is about 20 miles southwest of Townsend, Montana, where Mesozoic and Paleozoic carbonate, quartzite, and red-colored mudstone, siltstone, and sandstone rocks underlie Eocene (Chadronian) strata. These unconformable Eocene strata contain the Dog Town Mine vertebrate fossil locality.

Earl Douglass (yes, that Earl Douglass of the Dinosaur National Monument fame) first collected at the site on Friday, June 27, 1902 (based on transcriptions from Earl Douglass’ journals done by Alan Tabrum and volunteers from the Carnegie Museum of Natural History). According to his journal, Douglass met a man from Toston, Montana, on horseback and this person told him about the Dog Town Mine, which was located on the divide between the Toston/Townsend and North Boulder Valleys. Douglass was headed to the North Boulder Valley anyways, so he rode to the mine where he found invertebrate fossils (brachiopods and bryozoa) in carbonate rock which was in contact with the ore deposit. A Mr. Allen, who he dined with that evening, told him that more fossils could be found a little ways west of the mine. After dinner Douglass rode a short way west of the mine and found banks along a ravine that looked like Tertiary White River beds. Here he found  “Oreodont, Ischyromys, Palaeolagus, Titanotherium, and turtle remains” (June 28, 1902, Douglass Journal entry). This area is the present Dog Town Mine vertebrate fossil locality.

The Dog Town Mine site encompasses all of the light-colored exposures on the right side of the county road.
The Dog Town Mine locality encompasses all of the light-colored exposures on the right side of the county road seen in this photograph.

 

Tertiary strata at the Dog Town Mine are fine-grained, predominantly consisting of siltstone with minor fine-grained sandstone units. The deposits are probably of aeolian origin, originating from areal sediments rich in volcanic ash. These deposits are probably similar lithologically and in mode of origin to those Tertiary White River units found at high elevations within the Laramie Range and Medicine Bow Mountains (Evanoff, E., 1990, Early Oligocene paleovalleys in southern and central Wyoming: Evidence of high local relief on the late Eocene unconformity: Geology, v. 18, p. 443–446; Lloyd and Eberle, 2012, A late Eocene (Chadronian) mammalian fauna from the White River Formation in Kings Canyon, northern Colorado: Rocky Mountain Geology, v. 47, no. 2, p. 113–132).

Vertebrate fossils have been collected at the Dog Town Mine site for various museums since Douglass’ initial collection. The Carnegie Museum of Natural History in Pittsburgh, PA houses a collection from the site as well as the Museum of the Rockies in Bozeman, MT.

Earl Douglass and the Tertiary Geology of Southwest Montana’s Madison Bluffs

Most vertebrate paleontologists probably think of the spectacular dinosaur finds near Jensen, Utah, when the name Earl Douglass is mentioned. Douglass’s discovery of a partial Apatosaurus near Jensen in 1909  did spark the beginning of his long career with finding more dinosaur material in what we now know as Dinosaur National Monument. But Douglass began his quest for fossil vertebrates while he was in southwestern Montana – several years before he was summoned by the Carnegie Museum of Natural History’s director William Jacob Holland to find dinosaurs.

From the spring of 1894 to 1896, Douglass taught at a one-room school in the lower Madison Valley of southwestern Montana. The school house was located in the lower Madison Valley, directly west of the area known as the Madison Bluffs. These bluffs contain strata that range in age from probably as old as Eocene through the late Miocene. The strata are continental units that include alluvial fan to fluvial trunk stream deposits.

The school house near the Madison Bluffs, southwestern Montana, that Earl Douglass taught at from 1894-1896.
The school house near the Madison Bluffs, southwestern Montana, that Earl Douglass taught at from 1894-1896.
The Madison Bluffs consist of Tertiary fluvail/alluvial fan strata of probably Eocene to late Miocene age.
The Madison Bluffs consist of Tertiary fluvial/alluvial fan strata of probably Eocene to late Miocene age. The Madison Buffalo Jump State Park is located at the northwest edge of this photo.

During his tenure at the lower Madison Valley school, Douglass spent much of his spare time exploring the Madison Bluffs. At the beginning of his teaching contract in 1894, he had very little knowledge of vertebrate paleontology and of the area geology. He initially considered the Madison Bluff beds as Cretaceous in age. But when he found a “tooth very much like a Protohippus” (Earl Douglass journal entry on May 12, 1894), Douglass knew that the beds were younger in age. As time passed, he began to find a significant quantity of fossil vertebrate mammal material within the bluff’s deposits. Consequently, he immersed himself into reading about comparative anatomy so he could readily identify the fossil material. Douglass eventually used his collected fossil material for his 1899 Master’s thesis at the University of Montana – ostensibly the first Master’s degree awarded by the University.

horse jaw from douglass madbluff

Douglass kept journals of his time in the lower Madison Valley, and often detailed both the area geology as well as his fossil finds. Alan Tabrum and volunteers from the Carnegie Museum of Natural History have transcribed many of his journal entries from southwestern Montana. I’ve included two portions of journal entries to illustrate his finding of a horse jaw from the bluffs (above diagram) and one of Douglass’s drawings of “Big Round Top” (an area in the bluffs near the one-room school house) as compared to that same area today in a photo that I took about a week ago.

earldouglass_bigrt

It’s not difficult to understand how Earl Douglass became enthralled with the geology and paleontology of the Madison Bluffs. In addition to the fossil vertebrates, the bluffs contain many other fascinating geological features. Towards the central part of the bluffs (immediately south of the Madison Buffalo Jump State Park), calcic paleosol stacks mark the boundary between most likely Eocene and Miocene strata. The calcic paleosol stacks contain at least two generations of soil profiles (typically minus the A and upper part of the B horizons). Rootlets and burrows are commonly associated with these paleosols.

Volcanic tuffs also occur within the bluff’s strata, which is really handy for those of us who like isotopic age control for southwestern Montana Tertiary deposits. The tuffs could potentially help age constrain the paleosol stacks and sedimentation within the so far non-fossil bearing part of the bluffs. And with the help of the New Mexico Geochronology Lab, a group of us are working on just that aspect of Madison Bluff geology.

Calcic paleosol stacks in the central part of the Madison Bluffs, southwest Montana.
Calcic paleosol stacks in the central part of the Madison Bluffs, southwest Montana.
Roots within the calcic paleosols found at the Madison Bluffs.
Roots within the calcic paleosols found at the Madison Bluffs.
Burrows at the base of a calcic paleosol.
Burrows and roots at the base of a calcic paleosol.
Gray tuff found below calcic paleosol stacks.
Gray tuff found below the calcic paleosol stacks.

Iceberg Lake Glacier, Glacier National Park – Hiking Through A Changing Landscape

Iceberg Lake is situated in the Many Glacier area of Glacier National Park. The hike is about a 10 mile round trip and gains about 1275 feet in elevation. The trail winds through prime grizzly bear habitat, so be sure to hike with a group, make lots of noise, and carry bear spray. When I hiked the trail back in September, many returning hikers told our group about a grizzly sow and two cubs that were roaming around by Iceberg Lake. The bears actually walked by the lake shore while my group and many others were at the lake, but there were no harmful encounters. However – just this past week, in this same general area, a sow grizzly with 2 sub-adult cubs (I’m guessing that this is the same set of bears that walked by my group at Iceberg Lake) was surprised by a lone hiker and the sow grabbed and shook the hiker. The hiker used his bear spray escaped with puncture wounds to his lower leg and a hand. So – some words of caution about about hiking in bear country!

The Iceberg Lake Trail

A part of the Iceberg Lake Trail - note the u-shape valley sculpted by glacial processes.
A part of the Iceberg Lake Trail – note the u-shape valley sculpted by glacial processes.

The trailhead to Iceberg Lake is behind the cabins near the Swiftcurrent Motor Inn. The first part of the hike, about 1/4 mile, gains about 185 feet. After that initial elevation gain, the trail’s elevation gain moderates. Ptarmigan Falls is about 2.5 miles from the trailhead, and a short way above this is a footbridge that crosses Ptarmigan Creek. The rocky area near the footbridge is a great place for a snack break. Another 1/10 mile beyond the footbridge is the Iceberg Lake Trail junction. The Ptarmigan Trail continues towards the right and goes to Ptarmigan Tunnel and Ptarmigan Lake.Take the other trail branch to continue on to Iceberg Lake. A good trail hike summary for the Iceberg Lake Trail is found at the website “Hiking in Glacier”.

Footbridge over Ptarmigan Creek - good  place for a snack break.
Footbridge over Ptarmigan Creek – good place for a snack break.
Nearing Iceberg Lake as the snow and sleet continue to fall.
Nearing Iceberg Lake as the snow and sleet continue to fall.

The popularity of the trail was clear to me when even on a rainy, sleety, and snowy day,I passed many people on the trail. My group did a leisurely hike, stopping at several places to look at the geology alongside the trail and to do a snack stop by the Ptarmigan Creek footbridge both on the way up and back. It took us about 5 hours for the round trip. That put us back just in time to have a much enjoyed dinner at the Swiftcurrent Motor Inn.

Ah - the trail's end at Iceberg Lake!
Ah – the trail’s end at Iceberg Lake!

 

 

The Iceberg Glacier: Recession from 1940 to the Present

Comparisons of the Iceberg Glacier from 1940 to 2015. The photo on the left is a circa 1940 Hileman photo. GNP Archives; the center photo is a 8/14/2008 photo by Lisa McKeon, USGS, and the photo on the right is a 9/6/2015 photo by Debra Hanneman.
Comparisons of the Iceberg Glacier from 1940 to 2015. The photo on the left is a circa 1940 Hileman photo (GNP Archives) the center photo is a 8/14/2008 photo by Lisa McKeon, USGS, and the photo on the right is a 9/6/2015 photo by Debra Hanneman. Click on the photo to enlarge it in a new window.

The Iceberg Glacier is shown in the above photo set beginning in 1940 (this is the photo on the left, which is a Hileman photo from the Glacier National Park Archives) and ending with the 9/6/2015 photo on the right, which I took during my hike to Iceberg Lake. In the 1940 photo, the glacier terminus is quite thick and extends into the basin. By 2015, there is not much left of the glacier. Even with a comparison between the center 2008 photo by Lisa McKeon and my 2015 photo, one can see that much more bedrock is exposed. The older photos are also posted on the US Geological Survey’s Repeat Photography Map Tour Website. For those interested in glacial recession within Glacier National Park, the Repeat Photography website is a valuable resource. The Repeat Photography project is summarized on the USGS website –

This project began in 1997 with a search of photo archives. We used many of the high quality historic photographs to select and frame repeated photographs of seventeen different glaciers. Thirteen of those glaciers have shown marked recession and some of the more intensely studied glaciers have proved to be just 1/3 of their estimated maximum size that occurred at the end of the Little Ice Age (circa 1850). In fact, only 26 named glaciers presently exist of the 150 glaciers present in 1850.

Trail Geology

Sheet sands interbedded with muds in Proterozoic Grinnell Formation.
Jeff Kuhn points out sheet sands interbedded with muds in Proterozoic Grinnell Formation.

Much of the Iceberg Lake Trail winds through the Grinnell Formation, which is a Proterozoic geologic unit within the Belt Supergroup. As Callan Bentley has succintly said of the Belt Supergroup rocks in Glacier National Park:

The rocks exposed firstly from the top down are old sedimentary rocks of the Belt Supergroup. It is called “Belt” after Belt, Montana, and “supergroup” because it is immense. These rocks were deposited in a Mesoproteozoic (1.6-1.2 Ga) sea basin, and show little to no metamorphism despite their age.

Rip-up clasts in Proterozoic Grinnell Formation.
Rip-up clasts in Proterozoic Grinnell Formation.

I was lucky to be hiking with Jeff Kuhn from Helena, Montana, who has done much work with Belt Supergroup rocks in the Glacier Park to Whitefish Range areas. Jeff stopped us at several locations along the trail to look more closely at features within the Grinnell Formation. In general, the Grinnell Formation consists of sandstone and argillite and is approximately 1740-2590 feet thick. It has a deep brick-red color owing to its contained hematite and because it was deposited in a shallow oxygen-rich environment. Sedimentary features that are consistent with the shallow water depositional interpretation include mudstone rip-up clasts, mudcracks, and ripple marks.

Mudcracks preserved in the Proterozoic Grinnell Formation.
Mudcracks preserved in the Proterozoic Grinnell Formation.

All told, it was a hike well worth doing, even if you are not a geology enthusiast!

Ripples preserved in the Proterozoic Grinnell Formation.
Ripples preserved in the Proterozoic Grinnell Formation.

 

The Gravelly Range, Southwestern Montana: High Elevation Tertiary Rocks

The Gravelly Range is located in southwest Montana, about 10 miles southwest of Ennis, Montana. Much of the range is covered by the Beaverhead-Deerlodge National Forest. The Axolotl Lakes Wilderness Study Area, managed by the Bureau of Land Management, is in the northern part of the Gravelly Range.

Gravelly Range - looking east over Paleozoic rocks to the Madison Range in the far distance.
Gravelly Range – looking east over Paleozoic rocks to the Madison Range in the far distance.

Our field group was interested in looking at Tertiary rocks, so we headed for the Black Butte – Lion Mountain area, the more south-central part of the range. A cold front had just swept through western Montana a few days prior to my field trip. That storm left some snow up on the range crest – yep, that’s right, snow in July. But it did melt off fast and it left vegetation along the Gravelly Range road (the main road that stretches along much of the top of the range’s extent) extremely lush. So it was a gorgeous drive from the Lyon Bridge crossing on the Madison River up to Lion Mountain and Black Butte. And as Black Butte is the highest peak in the Gravelly Range at 10,542 feet in elevation, it was not difficult to find our destination.

Black Butte, at 10,542 feet  in elevation, is the highest peak in the Gravelly Range.
Black Butte, at 10,542 feet in elevation, is the highest peak in the Gravelly Range. Eruptions at Black Butte have a radiometric age date by whole-rock K-Ar of 22.9 Ma.
East side of Lion Mountain as seen from Wolverine Basin. Alkaline basalt caps Lion Mountain, with a K-Ar age date of 30.8 Ma.
East side of Lion Mountain as seen from Wolverine Basin. Alkaline basalt caps Lion Mountain, and has a K-Ar age date of 30.8 Ma.

The Tertiary rocks of interest to us were primarily the Tertiary strata exposed on the west side of Lion Mountain. Fossil fauna from these strata have a North American Land Mammal Age of Whitneyan, and are approximately 29 to 32 million years in age. Carnivore, rodent, insectivore, and rabbit are some of the fauna of the fossil assemblage collected here by past workers.

The west side of Lion Mountain with Tertiary strata exposed under the 30.8 Ma basalt cap.
The west side of Lion Mountain with Tertiary strata exposed under the 30.8 Ma basalt cap.

It was a good workout to reach the top of Lion Mountain, but really was well worth the effort. The Tertiary strata had plenty of features to keep a sedimentologist like myself busy. And the views – just spectacular! To top off the trip – it was obvious that someone had been there before us because we found an aluminum ladder stashed is the trees near the top of the Tertiary exposures. None of us availed ourselves of its use, but maybe next time it will come in handy!

A ladder stashed in the bushes near the top of Lion Mountain. The Snowcrest Range is shown in the distance on the left hand side of the photo. Black Butte pops over the ridge in the photo's upper right.
A ladder is stashed in the trees near the top of Lion Mountain. The Snowcrest Range is shown in the distance on the left hand side of the photo. Black Butte pops over the ridge in the photo’s upper right.

 

 

 

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.