A Little Crater Lake

Explanation: In the dense conifer forests of the Cascade Mountains of northern Oregon resides this most unusual water body. This is Little Crater Lake, located on Mount Hood National Forest. The lake is named after the far more well-visited and well-known Crater Lake and national park also located in the Cascade Mountains of Oregon, but in the southern part of the state.

Apparently, not much has been studied of this unique site, although a National Forest signboard on site describes its creation:

Before the lake was formed, this was a meadow, lying on top of layers of silt turned to soft stone called siltstone, which in turn lay on top of a gravel layer containing water under pressure, and beneath all that was dense bedrock.
Over time, the signboard teaches, the earth cracked and shifted along a fault line, and water under pressure was forced upward, creating a surface artesian spring.
Eventually, the spring grew in size and washed away the soft siltstone, so that today there sits a lake some 45 feet (14 m) deep fed by cold (34^oF, 1^oC) artesian waters from below.

Thus the crater lake was formed! And the lake today is a modest 0.2 acre (800 m²) in surface area, tiny for a "lake" but high in total water volume.

The incredibly blue and clear nature of the water is from the extremely low density of sediments. You can stand on the shore and see to the very bottom! It is a wonderful recreation site for visitors.

Information:
Shulters, M.V. 1976. Lakes of Oregon. Volume 4. Clackamas County. Prepared by the United States Department of the Interior Geological Survey. https://pubs.usgs.gov/publication/70199342

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