30,000 years ago the Wadena Lobe of the last glacier ceased its forward movement and melted in this area. The massive amount of ice, thousands of feet thick, was loaded with tons of boulders, stones, gravel, and other debris. Blocks of ice, buried in the debris, melted. As the ice melted, the overlying rocks and debris had no support, so they collapsed and formed a depression that filled with water to become a lake. This describes the formation of many of Minnesota’s “10,000” lakes. Lake Florida, which you see before you, is one of these ice block lakes. Ice block lakes tend to be deeper toward the middle of the lake and are frequently in the shape of a bowl. They are often surrounded by hills. The lake bottom is usually rocky or sandy, unless sediment, eroding from the surrounding land has found a way to flow into the lake, creating a silty bottom.
To get credit for this earth cache, email me the following answers:
- Describe the indicators of an ice block lake you observe on Lake Florida.
- Describe the composition of the lake bottom. How much sediment do you think has eroded into the lake? (If the lake is frozen, skip this question.)
- Estimate the distance across Lake Florida from this north side to the south side. 4. For verification purposes, what is the number of the 911 Address Sign at the Lake Florida PWA?