Intermountain Region

From Highway 89 head southeast on Highway 26 at Moran Junction toward Dubois, WY. Cliffs are located about 30 miles after the junction.

The Breccia Cliffs are comprised of volcanic breccias, conglomerates, and tuff that form the youngest member of the upper Absaroka Volcanic Supergroup called the Wiggins Formation. These cliffs are part of the southernmost portion of the Absaroka Range and it is thought that Absaroka Eocene age volcanism was rapid and violent. This often overlooked range in itself is quite spectacular. Originally formed from eruptions that piled volcanic debris, the forces of erosion and glaciation have since sculpted spectacular topography. Conveniently, the Breccia Cliffs are visible from the highway near Togwotee Pass.

This landmark is in the Teton Wilderness 50 miles northeast of Jackson, WY and about 7 miles south of the Yellowstone National park border. Site is accessible by a 15 mile hike from the Pacific Creek Trailhead (off Highway 89, just north of Moran Junction, at the end of Pacific Creek Road) or from the Turpin Meadow trailhead (on Forest Service Road 30050 east of Moran Junction).

Two Ocean Creek parts ways on the continental divide with one branch, Atlantic Creek, flowing east, and the other, Pacific Creek, flowing west. This point can claim to be part of the headwaters of both the Missouri and Columbia River systems. Origins of the Snake, Yellowstone, Colorado, and Green Rivers can also be traced to other regions within the Bridger-Teton National Forest.  Can you guess where Tri-Basin Divide is on the Bridger-Teton National Forest (see photo of sign below)?

At Hoback Junction, 13 miles south of Jackson, WY, head east on Highway 189/191 and follow the Hoback River south up the canyon. Take Granite Creek Road 10 miles east to Granite Hot Springs. Road is clearly marked.

In the mid-1930's the Civilian Conservation Corps ( CCC) constructed a cement container to capture the thermal heated water of Granite Hot Springs. Temperatures vary from 93 degrees F in the summer to 112 degrees in the winter. The 45 by 75 foot hot pool is bordered by large granite boulders and beautiful scenic views. Granite Campground is located about a mile away from the site.

The spring flows from the contact of the Cambrian period Death Canyon Limestone and Flathead Formation. Fluctuating flow indicates influence by surface waters. Seismic activity creates fractures where surface water seeps into the cracks, is transported deep within the earth, heats, and rises again to the surface through other fractures (Breckenridge et al.1978). Regionally, the thermal spring is located in the Gros Ventre Mountains that were thrust upward along the Cache Creek Fault millions of years ago. The peaks are mainly Paleozoic and Mesozoic age sedimentary rocks jaggedly carved through glacial activity ( Blackstone, 1988).

From Highway 191, just north of Jackson, WY, take the Gros Ventre Road past the town of Kelly to the Gros Ventre Overlook. If you are coming from the north, take Antelope Flat Road, then head south on Kelly Road to Gros Ventre Road.

In 1925, prolonged rainfall made the hill slope substantially unstable creating a large slide that formed a dam 225 feet high. It was estimated that about fifty million cubic yards of rock material moved. Almost two years later, the dam failed and practically destroyed the town of Kelly moving mud, rock, rubble, and water in a torrential push downstream. The slide area can be seen from many miles away as you approach the canyon and an interpretive trail, signs, and overlook are located at the slide area. Large boulders and rubble fill the canyon below Lower Slide Lake.

Geologically speaking, the mountains in this area are relatively young and still quite active. Earthquakes can be felt throughout the year as evidenced by many small slumps present, but none as catastrophic as the Gros Ventre Slide.

Located along the Hoback River off of 189 about 5 miles from Hoback Junction, WY.

Located near the mouth of Hoback Canyon, no interpretive signs mark the location, but the spring’s presence is obvious at a small gravel pullout when compared to the natural river system beside it. Caribbean blue waters seem out of place next the normal green hues of the running water. The spring enters the river just a few feet above the water level from a talus slope opposite the road. Once again, as described with other various springs on these pages, seismic activity comes into play. Near the spring, Mississippian carbonate rocks are complexly folded and thrust-faulted. The thrusting is associated with the hanging wall of the Shepard thrust (Roberts, 1990). Surface waters seep into the fractures dissolving carbonate rocks along the way and exit the fracture depositing calcium carbonate deposits. This is likely the cause of the apparent milky- blue color in the water. An obvious sulphur smell gives these hot springs their characteristic name.

From Highway 89 in Afton, WY, head west on Forest Service Road 10211, a gravel road that winds through the canyon for about four miles. The Periodic Spring Trail follows the creek side for about 1/2 mile to Periodic Spring.

Situated at the base of limestone cliffs, Periodic Spring discharges about 285 gallons per second. Spring water gushes from an opening for several minutes, stops abruptly, then begins a new cycle a short time later. Intermittent water flows range anywhere from four to 25 minutes and the water is clear and cold. This is a very rare type of spring with only a few known in the world. Unlike thermal geysers, where water is heated and pressurized, this spring has disputed theories as to its perplexing behavior. One theory suggests siphoning action. Water fills a subsurface reservoir and flows freely from the opening until the water level drops below the siphon intake. The reservoir then refills and the process starts all over (Corliss, 1990; Mohlenbrock, 1990).

From Pinedale , WY take Fremont Lake Road just east of Faler's General Store. At 2.5 miles, you'll pass an overlook with interpretive signs and a great view of the lake. Continue to 3.2 miles and follow the signs.

Fremont Lake is the second largest lake in Wyoming as well as one of the deepest lakes (600 feet) in the United States. Pleistocene glaciers of the Bull Lake and Pindale glacial periods carved out the valleys in this area and deposited terminal moraines that dammed the mountain waters. Fremont, New Fork, Half Moon, Boulder, and Willow Lakes all formed in such a manner. The massive glacial moraines surrounding Fremont Lake are classic examples of moraines formed by alpine glaciation.

Moraines are made of rock debris, fallen or plucked from a mountain and transported by glaciers. The piles of debris show where the terminus of the glacier paused for a while. Till is another word used to describe the sediments left by melted glaciers.

The Bull Lake Glaciation is a glacial period that began roughly 200,000 years ago and ended 130,000 years ago when a large sheets of ice began carving valleys in the Rocky Mountains. The name Bull Lake Glaciation itself is derived from the well-preserved moraines found in the vicinity of Bull Lake near the Wind River Mountains but also sent a valley glacier down Pine Creek where Fremont Lake is today. The Bull Lake Glaciation was immediately followed by a much warmer interglacial period that lasted roughly 60,000 years, preceding the advance of the Pinedale Glaciation.

The Pinedale glaciation was the last of the major ice ages to appear in the Rocky Mountains. The Pinedale lasted from approximately 30,000 to 10,000 years ago and was at its greatest extent between 23,500 and 21,000 years ago. This glaciation was somewhat distinct from the main Wisconsin glaciation as it was unrelated to the giant ice sheets and was instead composed of mountain glaciers. The Pinedale glaciers overrode the Bull Lake moraines in the Pinedale area.

Look for the characteristic U-shape valleys as well as residual glaciers that still occupy the higher peaks. Glacial features such as horns and steep-walled cirques are also present in the Wind River Mountains (Blackstone, 1988).

Just after entering the Forest on LaBarge Creek Road , turn right up a dirt road ( Forest Service Road 10089) that follows Big Fall Creek.

Multiple waterfalls over spring-deposited tufa make this creek an interesting visit. The creek follows tufa terraces and falls for two miles. The cold springs are located in the Triassic Dinwoody Formation, but the source of the water is probably the Madison Limestone to the east. The area is associated with the Cabin Creek overthrust, part of the imbricate thrusting seen in this area of Wyoming.  (Breckenridge et al. 1978).

Tufa is found mainly in areas where resurgences of ground water have traversed limestone formations. The tufa is spongy or cellular in character and encloses fragments of rocks and plants. It also cements the bottom of the streambed into a material known as calcrete. The build up of tufa encrusted moss, algae and other debris create barriers to stream flow and produce water falls and cascades. The water in the stream has a distinct sulfer smell. Sulfer is a common element in sedimentary rocks and dissolves readily into ground water.