Erratic Behavior on the Cannon River
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This is not your typical P&G EC, but rather your ATYPICAL "Paddle & Grab" EC on the scenic Cannon River, west of Miesville. Land to water access will require wading through water from the Cannon Valley Bike Trail nearby. Thus, the 5 terrain rating.
A glacial erratic is a piece of rock not native to the area in which it has come to rest, ergo the name “erratic” or errant location. These rocks were often carried hundreds of miles with the advance of the glaciers and then deposited during the “retreat” or the melting phase.
This topography of this particular region of Minnesota was most recently shaped by the advance and retreat of the Des Moines Lobe of the Wisconsin Ice Shield approximately 14,000 -12,000 years ago. As the glacier retreated, the melt waters carved the river valleys, exposing evidence of the inland sea history, depositing the sediments creating the rich soil base of this region and a lot of really big rocks!
The coordinates listed above will bring you to one of the many large travelers in this region. This one is located in the Cannon River itself. This boulder has stood the test of time but is slowly succumbing to the erosive forces of the river.
These exotic rocks originated from regions north, including Canada. The continental glaciers of the Great Ice Age scoured and scraped the land surface as they advanced, pushing up chunks of bedrock and grinding them against each other or along the ground surface as the rock-laden ice sheets pushed southward.
Often one can tell where the erratic originated from by determining the kind of rock it is. A large boulder of granite, gneiss, or other igneous or metamorphic rock may have come from Canada. Some are colorful and glittering granites, banded gneisses, and other intricately veined and streaked igneous and metamorphic rocks. Some erratics containing flecks of copper were probably transported here from the "Copper Range." Large pieces of copper have been found in glacial deposits through out the upper Midwest region. Light gray to white quartzite boulders with beautiful, rounded pebbles of red jasper came from Ontario, Canada. Purplish pieces of quartzite, some of them banded, probably originated in Wisconsin.
Most interesting are the few large boulders of Canadian tillite. Glacial till is an unsorted and unlayered mixture of clay, sand, gravel, and boulders that vary widely in size and shape. Tillite is glacial till that was deposited by a glacier many millions of years older than the ones that invaded our state during the Great Ice Age. This glacial till has been around so long that it has hardened into a gray to greenish gray rock containing a mixture of grains of different sizes and scattered pebbles of various types and sizes.
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****** PLEASE NOTE THIS IS RATED AS A 5 TERRAIN EARTHCACHE AND REQUIRES YOU TO BE ON OR IN A SHALLOW RIVER. IF YOU ARE NOT “WATER-FRIENDLY”, DO NOT ATTEMPT THIS CACHE. THE WATER LEVELS AND CURRENT SPEED OF THE CANNON RIVER WILL VARY WITH SEASON AND RAINFALL.
******IT IS MINNESOTA LAW TO WEAR A SAFETY FLOATATION DEVICE WHILE ON THE RIVER. APPROACHING THIS EARTHCACHE IS AT YOUR OWN RISK. PRACTICE SAFETY FIRST!
LOGGING REQUIREMENTS FOR THIS EARTHCACHE ARE AS FOLLOWS:
1. Please e-mail me with the full height (including amount of rock under water level), length and width of the erratic.
2. Please note what is happening to the shape of this erratic on the channel side of the river.
3. Please note the type of rock this is and colours within.
4. Please post a photo of yourself and your GPS unit next to the erratic.
5. Please make sure you double baggie any electronics and fasten them securely to your watercraft! ?
If you do not meet these logging requirements, your log will be deleted. This is a standard requirement of EarthCaching.
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