Teaching Petrology: Grand Canyon of the Yellowstone

Evening at the Grand Canyon of the Yellowstone

The Yellowstone River has cut a deep, steep-walled gorge into hydrothermally altered ignimbrites in the Yellowstone caldara floor. Many of the rocks have been leached white by the hydrothermal solutions, others have been stained red (hematite) or yellow (limonite) by iron. Hydrothermal alteration continues and wisps of steam can frequently be seen on the canyon walls. These photos were taken from and near Artist’s Point.

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Location map for Artist Point, on the south rim of the Grand Canyon of the Yellowstone. Canyon Village is just north of this map, and actually a few of the village cabins are visible at the map top.

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Looking down the steep walls of the canyon. The Yellowstone River is hidden below the slopes.

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Cliff overhanging the canyon. These rocks are hydrothermally altered and most are quite weak and crumbly.

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Tall view of the Yellowstone River at the bottom of its canyon. View is upstream to the west.

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Wide view of the Yellowstone River at the bottom of its canyon. View is upstream to the west. Do you see those more or less horizontal lines on the right side? Are they goat or deer tracks? I sure hope not, that’s too scary to contemplate.

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Canyon in the opposite direction. View is downstream looking east.

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Looking down into the canyon. Downstream, and east is to the upper right.

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The north side of the canyon, looking northeast. Small dark spots in the center are elk crossing the ~40° slope, with young. They must be nuts.