Missouri River EarthCache EarthCache
Missouri River EarthCache
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The aim of this EarthCache is to learn about the geological and
geographic make up of the Missouri River. Once you reach the
coordinates you are required to answers some questions and take a
photo which is to be attached to your log.
Geography
The Missouri River stretches 2,341 miles from Three Forks, Montana
to where it meets the Mississippi River at St. Louis, Missouri,
making it the longest river in the United State. The Missouri River
drains about one-sixth of the continental United States with a
Basin Area of 529,350 square miles The headwaters of the Missouri
are in the Rocky Mountains of southwestern Montana, near the small
town of Three Forks, rising in the Jefferson, Madison, and Gallatin
rivers. The longest headwaters stream begins at Brower's Spring,
which flows to the Jefferson by way of several other named streams.
From the confluence of its main tributaries near the city of Three
Forks, the Missouri flows north through mountainous canyons,
emerging from the mountains near Great Falls, where a large
cataract historically marked the navigable limit of the river. It
flows east across the plains of Montana into North Dakota, then
turns southeast, flowing into South Dakota, and along the north and
eastern edge of Nebraska, forming part of its border with South
Dakota and all of its border with Iowa, flowing past Sioux City and
Omaha. It forms the entire boundary between Nebraska and Missouri,
and part of the boundary between Missouri and Kansas. At Kansas
City, it turns generally eastward, flowing across Missouri where it
joins the Mississippi just north of St. Louis.
Geology
Beginning about 5 million years ago, regional uplift of the western
part of the continent forced streams, which for 30 million years
had been depositing sediment nearly continuously on the Great
Plains, to change their behavior and begin to cut into the layers
of sediment they so long had been depositing. The predecessor of
the Missouri River ate headward into the northern Great Plains and
developed a tributary system that excavated deeply into the
accumulated deposits near the mountain front and carried away huge
volumes of sediment from the Great Plains to Hudson Bay. By 2
million years ago, the streams had cut downward to within a few
hundred feet of their present level.
About 2 million years ago, after much downcutting had already taken
place and river channels had been firmly established, great ice
sheets advanced southward from Canada into the United States. These
continental glaciers formed, advanced, and retreated several times
during the last 2 million years. At the north and east margins of
the Missouri Plateau they lapped onto a high area, leaving a mantle
of glacial deposits covering the bedrock surface and forcing
streams to adopt new courses along the margin of ice. The part of
the Missouri Plateau covered by the continental glaciers now is
referred to as the Glaciated Missouri Plateau. South of the part
once covered by ice is the Unglaciated Missouri Plateau.
The river is nicknamed "Big Muddy" and also "Dark River" because of
the high silt content. The river meanders from bluff to bluff in
the flat Midwestern states, leading to the nickname the "Wild
Missouri".
Please take care while visiting this EarthCache. There is no
need to enter the river to answer any of the questions or take your
photo.
To log this EarthCache you must perform the following tasks:
Email me or message me under my profile answers to the
following questions:
1) At the listed coordinates find the sign and start reading:
A) How many segments of the Missouri are untamed in this portion of
the river?
B) On the map, name the 2 islands listed that are located on the
Missouri River between Mulberry Bend and Riverside Park.
2) Estimate the width of the Missouri River at the EarthCache
location. (Remember to exclude the island right in front of
you)
3) How much of the continental United States does the Missouri
River drain?
4) What is one of the three nicknames given to the Missouri
River?
** In your log ** Post a photo of yourself or group holding
your GPS with the Missouri River in the background.
Do NOT post any of the answers in your log.
Additional Hints
(No hints available.)