River Bend EarthCache
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In order to count this earthcache as a find, you must complete the following tasks and email the answers to me.
1. What is the name of the present-day park where the Big Sioux River flowed to before being diverted to the north?
2. What are the names of the creeks the Big Sioux River joined up with before resuming its southerly flow?
3. Considering how the area looks today, how would the area differ if the James Lobe had not redirected the river?
4. What is the current speed of the river's flow (slow, medium, fast)? How would the speed differ if the James Lobe had not redirected the river?
This cache is located in the western part of Yankton Trail Park in Sioux Falls. Near the earthcache site flows the Big Sioux River. The bike trail also winds through this park and crosses the river at an old, historic bridge. Enjoy!
The Coteau des Prairies (or “hills of the prairie”) is a plateau that rises from the prairie flatlands and stretches about 200 miles from north to south and 100 miles from east to west. It covers much of eastern South Dakota, southwestern Minnesota, and northwestern Iowa This plateau is one of the most conspicuous landforms of the US midcontinent that can be seen on a relief map. Shaped like a flat iron, the plateau received its name from early French explorers from Quebec, a French speaking province. “Coteau” is the French word for “slope.”
The plateau is composed of thick glacial deposits, which were the remnants of many repeated glaciations. Beneath the glacial deposits is a small ridge of resistant Cretaceous shale. (Shale is a sedimentary rock that is formed from clay that is compacted together by pressure. Shale is used to make bricks and other material that is fired in a kiln.) Another type of deposit found on the plateau is pipestone. Pipestone (a brownish-red mineral) has been quarried for hundreds of years by Native Americans, who use the mineral to make sacred peace pipes. One of these quarries is located at Pipestone National Monument near Pipestone, MN, which is also located on the Coteau des Prairies.
The last glaciation in the area began 36,000 years ago during the late Wisconsin Stage. By then, the plateau had become a barrier for the south-flowing glacier and divided the ice sheet into two lobes (tongue-like extensions of the main ice sheet). These lobes, the James Lobe to the west and the Des Moines Lobe to the east moved south along pre-glacial stream valleys on either side of the plateau. When the James Lobe reached the nearby southwest corner of the plateau, it turned to flow east.
In time, the glacier began to recede. Meltwater flowing south down the Skunk Creek and Big Sioux River valleys was dammed by the James Lobe, causing it to flow east for about two miles. There it was diverted several miles north before joining up with smaller creeks and then resuming its southerly flow. In this manner, the Great Bend of the Big Sioux River was created by the James Lobe about 15,000 years ago.
Today, the Coteau des Prairies has not yet been extensively drained and still has numerous small glacial lakes and wetlands. The Big Sioux River works to drain the area.
NOT A LOGGING REQUIREMENT: Feel free to post pictures of your group at the area or the area itself - I love looking at the pictures.
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