From the top of this 500-foot bluff, the confluence of the Wisconsin River and the mighty Mississippi may be seen to the south. To the north, the view of the bridges connecting Iowa and Wisconsin is breathtaking.
Pikes Peak State Park is located in the "Paleozoic Plateau" that was missed by the glaciers that flattened and molded so much of Iowa. This area, often called the "Driftless" region, is noted for its natural beauty. Its hills and valleys offer great vistas, large timbered tracts, spring-fed streams and a natural beauty unique to northeast Iowa.
The melting of those enormous ice sheets that, at their maximum, were 5,000 to 10,000 feet thick and covered hundreds of thousands of square miles, released tremendous amounts of water, forming huge glacial lakes. The largest of the glacial lakes, Lake Agassiz, covered northwest Minnesota, parts of North Dakota and the Canadian provinces of Manitoba, Saskatchewan and Ontario. The southern discharge outlet to this lake was called Glacial River Warren, which eventually excavated the valley now occupied by the Minnesota River. (The Mississippi River flows into the valley carved by the River Warren at St. Anthony Falls in Minneapolis.)
The St. Croix River which drained Lake Duluth, a glacial lake that covered the western Lake Superior basin, joined the River Warren about 30 miles downstream from the present confluence of the Mississippi and Minnesota Rivers. In Wisconsin, another glacial lake drained first into what is now the Black River and later the Wisconsin River, both of which emptied into the River Warren. During the 3,000 years that River Warren carried water from these and other smaller glacial lakes, the Mississippi River valley was carved bluff to bluff and the resulting valley was approximately 250 feet deeper than it is today.
However, there is also evidence that the main valley is much older than the River Warren and underwent several cycles of cutting and filling during the Great Ice Age. Even though the Coulee country escaped the land-leveling effect of the ice mass, the glaciers left their mark by carving the spectacular Mississippi River that cuts through the heart of this area with the torrents of water draining from the melting ice mass.
To receive credit for this EarthCache, you will need to complete the following tasks.
In an e-mail to me, please tell me the following:
Across this gorge of the Mississippi River is the Wisconsin River. Please tell me what type of rock the river valleys are carved into.
Where did these layered rocks originate? Is there any evidence that these rocks originated there?
Approximately when did the geologic event end that formed these valleys?
Please describe how strong the current must be at this point in the River. (think of how much of a bend you see, how deep is the valley?)
When you log this EarthCache, please upload a picture of yourself/team with your GPS clearly visible with the river valley in the background.
Logs that do not meet these five criteria Will Be Deleted- No Exceptions!