Lake Traverse 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 elevation at the continental divide?
2. Using the tick marks on the side of the dike and the elevation of the continental divide, estimate the elevation of the Lake.
This earthcache is located at the Browns Valley Recreation Area on the south end of Lake Traverse. The area is well kept and has plenty of space for parking. Bathrooms and picnic tables are also available here. Enjoy the area!
Lake Traverse is the southernmost body of water in the Hudson Bay watershed and is one of the area’s largest lakes. This lake was formed when the glacier that once covered the area retreated, but not from chunks of ice. As the glacier melted, it sent strong and fast-moving streams of water southward. This water dammed up behind a barrier of glacial debris known as the Big Stone Moraine and pooled into a lake larger than all the Great Lakes combined. This lake, which held more water than contained by all lakes in the world today, was known as Lake Agassiz and covered much of Manitoba, western Ontario, northern Minnesota, eastern North Dakota, and Saskatchewan.
Eventually, the lake rose high enough to carve a channel through the Big Stone Moraine (the barrier of glacial debris). The outflow of Lake Agassiz carved a gorge through the moraine that was a mile wide and 130 feet deep. This gorge is now called the Traverse Gap. The spillway that flowed through this gap came to be known as Glacial River Warren. The river worked to drain the meltwater of Lake Agassiz to the Mississippi River Valley. As the glacial meltwater found other outlets, the current in River Warren began to slow and the formation of Lake Traverse began.
The Traverse Gap marks the northern divide between the watersheds of the Arctic and the Atlantic Oceans. Lake Traverse, to the north of this divide, flows northward and drains into the Atlantic Ocean via the Hudson Bay, while Big Stone Lake, to the south of the divide, flows southward to the Gulf of Mexico and into the Atlantic Ocean. Today, Lake Traverse, Big Stone Lake, and the valley connecting them at Browns Valley, Minnesota occupy the ancient river channel of the Traverse Gap. The Traverse Gap has an unusual distinction for a valley: it is crossed by a continental divide, and in some floods, water has flowed across that divide from one drainage basin to the other. In 1941, a dike was constructed at the south end of Lake Traverse. This structure was built to reduce the likelihood of flooding south across the continental divide.
In 1966, the Traverse Gap was designated as a National Natural Landmark and recognized as an outstanding example of a geological feature of the United States’ natural history. The designation describes it as “a channel cut by the Ancient River Warren during the Ice Age, containing the Hudson Bay-Gulf of Mexico divide, with a lake on each side as evidence of the irregularities in Ice Age sedimentation.”
Today, Lake Agassiz and Glacial River Warren have completely drained. All that remains are the Traverse Gap, the lakes Traverse and Big Stone, which were formed by the glacial meltwater, and the Little Minnesota River, which flows through the ancient channel and drains into Big Stone Lake.
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.
Additional Hints
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