The formation of the Grand Tetons

The sky-high Grand Teton Range of the Rocky Mountains in Wyoming is beautifully mirrored at sunrise in the Oxbow Bend at Schwabachers Landing. The peaks from left to right are South, Middle and Grand Teton, Mount Owen and Teewinot.
This impressive mountain range lifted through intense sporadic earthquake-producing jolts while the adjacent valley of Jackson Hole subsided, which includes the Snake River. This explains the absence of foothills giving direct view of lofty jagged peaks and deeply carved canyons. Towering 1600 m (one mile) above Jackson Hole, the Grand Tetons rise to 4197 m (13770 ft) above sea-level. Although being the youngest in the Rocky Mountain system, they display 2.5 billion years old granites and gneisses. Enormous tensional faults fractured the Jackson Hole formation 9 million years ago. Two rectangular blocks of the Earth’s crust moved like giant trapdoors, one swinging skyward to form the mountains, the other hinging downward to create the valley. The sandstone remnants on today’s peaks were once connected to the layer that now lies an estimated 24000 feet (7300 m) below the valley floor. Rain, ice, and wind constantly eroded the sedimentary layers off the central peaks, uncovering resistant granite and gneiss. Cascading water cut steep gorges into the rising range. The eroded material filled Jackson Hole and hence leveled the sinking valley.
Legend has it that the Tetons were named by needy French trappers. They called the mountains “les trois tetons”, which means “the three breasts”. This leaves little doubt about the meaning of the name Grand Teton. However, the name could be much less poetically derived from the Lakota Native Americans, who also called themselves Teton Sioux tribe. Whatever the origin of the name is, the Grand Tetons are certainly a magnificent sight at Schwabachers Landing in the Oxbow Bend.