Minnesota Point is the world's largest fresh water baymouth sandbar. It is a beach system formed from the eroded sand carried here by the St. Louis River as well as the Nemadji River. It began forming about 3,200 years ago. It is produced by longshore currents when waves hit the beach at an angle. A wave in deeper water will move faster than the part that is reaching the shore producing longshore currents. This moves the sand in the direction of the wave, predominately from the east here, moving sand from the lake shore along Wisconsin, which has closed off the whole mouth of the bay, as of just a few centuries ago.
This large levy forms a safe harbor for ships, to access it from Lake Superior a canal has been dug on the Duluth side of the bar to augment the natural opening on the Superior side. These canals must be dredged on a regular basis as they are always filling in with sand from the continuous wave action of Lake Superior and the St. Louis and Nemadji Rivers constantly bringing more sediment into the harbor.
To log this EarthCache, complete the following tasks and send your results to the cache owner listed at the top of this page: click on their name, then either the 'Send Email' or 'Send Message' link -
1. Make your way to the posted coordinates. How high do you estimate this point of the sandbar to be above the lake and harbor? 1a. How wide do you think it is?
2. Using your GPSr or other hand-held device, what is your elevation above sea level here?
3. Look down at the soil beneath your feet. Do you think it was brought here by the rivers or the lake? Why?
If you would like to include some photos with your log that's always appreciated, although they are not a requirement for logging this EarthCache.
