Geology and Ecology of National Parks

Grand Tetons National Park Geology Photo Tour

 

Grand Tetons National Park

Jackson Lake: Grand Teton National Park in northwestern Wyoming was established in 1929. This view looking south from the northern park road (Highway 89-191-287) shows Jackson Lake and the fault-bounded range front of the eastern Teton Range (Love and others, 1973). The partially dammed lake is at the north end of the valley named Jackson Hole (Harris and others, 1997).

(Credit: Phil Stoffer, USGS. Public domain.)

Grand Tetons National Park

This view is of Mount Moran, elevation 12,588 feet above sea level (derived from the National Elevation Dataset), in the central Teton Range. The very top flat part of the mountain is a caprock of Cambrian Flathead Sandstone that unconformably overlies the Precambrian crystalline rocks that make up the core of the Teton Range. The east side of the range is bounded by the Teton fault. The fault has vertically offset the Flathead Sandstone by about 30,000 feet. On the east side of the fault, the Flathead Sandstone is buried deep beneath sedimentary cover deposited in the valley of Jackson Hole. Most of this fault displacement probably having occurred in the past 9 million years (Love and others, 1973; Love, 1987; Love and others, 1992).

(Credit: Phil Stoffer, USGS. Public domain.)

Grand Tetons National Park

View of the northern Teton Range and Jackson Lake. Sharp, serrated ridges and mountain peaks stand out in contrast to the deep U-shaped glaciated valleys in the Teton Range. This view shows Mount Moran (center right) and Mount Woodring (to the left of Mount Moran).

(Credit: Phil Stoffer, USGS. Public domain.)

Grand Tetons National Park

This view is of Mount Moran near Jackson Lake Junction. The Teton Range rises nearly 5,000 to 7,000 feet above the valley (Jackson Hole). The mountain range is a fault-block with a great escarpment on its eastern side where vertical displacement along the Teton normal fault has occurred (Love, 1987). The range core consists of Precambrian metamorphic rocks (gneiss and schist) and granite. Sunlight highlights a vertical diabase dike near the peak of Mount Moran. The age of the crystalline rock in the Teton Range is about 2.5 to 2.8 billion years old, whereas the intrusive dikes are about 1.3 billion years old. The summit is capped by a relatively thin layer of Cambrian Flathead Sandstone. (Love and others, 1973; Love, 1987; Reed and Zartman, 1973, Harris and others, 1997).

(Credit: Phil Stoffer, USGS. Public domain.)

Grand Tetons National Park

View of the Grand Teton Range along the Teton Park Road. The rugged landscape was partly shaped by alpine glaciers. The carved U-shaped valleys, cirques, and hanging valleys. A piedmont glacier filled parts of Jackson Hole valley to a depth of about 2,000 feet during the last ice age (Harris and others, 1997). Today, small remnants of glaciers and ice fields remain, and lakes in the valley fill low areas that were once filled with glacial ice.

(Credit: Phil Stoffer, USGS. Public domain.)

Grand Tetons National Park

This view shows Grand Teton (elevation 13,779 feet above sea level; derived from the National Elevation Dataset), the highest point in the Teton Range, rising above Jackson Hole. Much of Jackson Hole is a sagebrush desert. Summer high temperatures are typically pleasant, whereas winter temperatures can be severely cold.

(Credit: Phil Stoffer, USGS. Public domain.)

Grand Tetons National Park

The National Park Service maintains a large bison herd in the southeastern end of the park. Grand Teton is the highest peak in the range.

(Credit: Phil Stoffer, USGS. Public domain.)

Grand Tetons National Park

This view of the southern Teton Range is looking across elevated stream terraces covered with sagebrush. Pine, apsen, cottonwood, and willow forests grow on the forested floodplain of the Snake River.

(Credit: Phil Stoffer, USGS. Public domain.)

Grand Tetons National Park

This zoomed-in view from Highway 191 (between Jackson and Moran Junction) highlights a glaciated valley on the north side of Grand Teton. Elevated stream terraces along the Snake River are in the foreground.

(Credit: Phil Stoffer, USGS. Public domain.)

Grand Tetons National Park

View of the Snake River, river terraces, and the Teton Range from the Snake River Overlook along Highway 191.

(Credit: Phil Stoffer, USGS. Public domain.)

Grand Tetons National Park

View of the Grand Tetons from near the Snake River Overlook.

(Credit: Phil Stoffer, USGS. Public domain.)

Grand Tetons National Park

Wide-angle view of the Teton Range and the Snake River terraces and floodplain.

(Credit: Phil Stoffer, USGS. Public domain.)

Grand Tetons National Park

The Gros Ventre Slide was one of the largest historic landslides in North America. The landslide occurred on June 23, 1925. The landslide occurred where steeply-dipping rocks of late Paleozoic age were undercut by the Gros Ventre River. Heavy rains and spring snow melt may have been contributing factors as well. The volume that slid was nearly a mile long, 2,000 feet wide, and several hundred feet thick-estimated at about 50 million cubic yards. In a matter of minutes the landslide moved into the valley and dammed the Gros Ventre River. A large lake formed behind (upstream) of the landslide. On May 18,1927, the natural dam partially failed, and a great flood of water, rock, and debris washed down the valley causing catastrophic damage to the town of Kelly, Wyoming and several ranches in the valley below. At least six people were killed in the flood. Today the area is preserved as the Gros Ventre Geological Slide Area within the Bridger-Teton National Forest (Alden, 1928; Voight, 1974; USFS, 2008).

(Credit: Phil Stoffer, USGS. Public domain.)

Grand Tetons National Park

This view is looking down onto the toe area of the Gros Ventre Landslide. Boulders, mostly Tensleep Sandstone, litter the surface of the landslide. They also cover much the stream valley below the slide area-carried downstream in the flood when the natural dam formed by the landslide failed.

(Credit: Phil Stoffer, USGS. Public domain.)

Grand Tetons National Park

The forest has grown back since the landslide occurred in 1925. Barren areas are locations where there is little or no soil, or where smaller, more recent landslides have occurred.

(Credit: Phil Stoffer, USGS. Public domain.)