Teton Range

The Teton Range is a small but dramatic mountain range of the Rocky Mountains in North America. A north-south range, it is on the Wyoming side of the state's border with Idaho, just south of Yellowstone National Park. The two principal summits are the Grand Teton at 13,772 ft (4198 m) and Mount Moran at 12,605 ft (3842 m); most of the range is within the Grand Teton National Park.

Between six and nine million years ago, stretching and thinning of the Earth's crust caused movement along the Teton fault. The west block along the fault line was pushed upwards to form the Teton Range, thereby creating the youngest range of the Rocky Mountains. The fault's east block fell downwards to form the valley called Jackson Hole. While many of the central peaks of the range are comprised of granite, the geological processes that lead to the current composition began about 2.5 billion years ago. At that time, sand and volcanic debris settled into an ancient ocean. Additional sediment was deposited for several million years and eventually heat and pressure metamorphosed the sediment into gneiss, which comprises the major mass of the range. Subsequently, magma was forced up through the cracks and weaknesses in the gneiss to form granite, anywhere from inches to hundreds of feet thick. This ancient magma has manifested itself as noticeable black dikes of diabase rock, visible on the southwest face of Mount Moran and on the Grand Teton. Erosion and uplift have exposed the granite now visible today.

Pictures of the area

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tetoncam.com provides a live webcam image of the Grand Teton from the Idaho side.

Main article: Geology of the Grand Teton area

References

• America's Volcanic Past - Wyoming

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43°45′N 110°50′W