This earth cache is located in Robinson Park in Sandstone, Minnesota. It is at the site of a former rock quarry along the banks of the beautiful Kettle River. Remnants of the quarry buildings can be explored here and the old bridge ruins that once served as a horse and wagon crossing are still visible.
At the earth cache coordinates, you are able to see the walls or cross sections of some awesome rock hills that were formed millions of years ago. These walls represent only a fraction of how deep these rock layers go as they reach many more miles downward to their origins near the earth’s core!
Geologists classify this rock as granite and more specifically as metamorphic granite. Metamorphic means that the rock had metamorphasized or changed as it was thrust upward. This change was due to the extreme heating and cooling which created the texture and the mineral composition of this rock. Generally, the colors of granite can be attributed to: Quartz- Clear pink and white; Feldspar- Pink and red; Mica- Dark brown; Iron- Orange and rust; Amphibole- Black.
This stone wall is beautiful year round, but looks especially spectacular in the winter when water seeps over the cliffs and freezes into columns of ice. You may see ice climbers here, since this wall is considered to provide some of the best ice climbing in the upper Midwest. An Ice Fest is held each year in January which focuses on ice climbing.
To receive credit for this earth cache, email to me the answers to the following questions:
- Estimate the height of the wall of rock.
- Describe the color and texture of the different rock layers you can touch. What created these colors?
- Explain the origin of this wall of rock and how it was formed.
- Optional- Take a photo of yourself at the wall of rock.