• Speleothems in Miller's Chapel.

    Oregon Caves

    National Monument Oregon

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    Haunted Candlelight Tours Offered Sunday, October 26 through Friday, October 31, 2014. The tour begins at 4pm and are first come first serve. The tour is limited to 12 people per group.

Speleogenesis- Creation of Cave


Over several million years, the belt of marble within the Siskiyou Mountain cracked as the land uplifted and folded. At the same time, the top of the mountain weathered and exposed the marble to the surface of the earth. A forest grew over the marble and in the forest soil, fungi, bacteria, and mold decomposed dead plants and animals releasing carbon dioxide. Precipitation percolated through the soil and captured the carbon dioxide to create carbonic acid. This mild acid is the same stuff that gives soda pop its fizz.

The acidic water then chemically weathered the marble bedrock as it traveled downward through the cracks and holes in the rocks. Ground water moved downward until it reached the water table--an area where all available pore space in rocks are filled with water. The greatest amount of marble was dissolved just below the water table where the highest concentration of carbonic acid occurred. Water then spreads sideways along the cracks in the bedrock and the carbonic acid slowly dissolved the marble. Over hundreds of thousands of years, the carbonic acid enlarges small cracks into larger cavities as the marble was carried away (eroded) in solution. The process of dissolving marble and opening up spaces within it is called speleogenesis. Speleogensis is derived from the Greek words "spelaion" (cave) and "genesis" (beginning).

Did You Know?

Horse riders rode about 12 miles to Cave Camp located next to the entrance of Oregon Caves.

Up until 1922 the only way to get to Oregon Caves was on a 12 mile trail from the town of Williams, Oregon. Once at Oregon Caves visitors explored the cave and spent the night at a camp outside the entrance to the cave.