The Central Mississippi River Valley
The Central Mississippi River Valley I chose to write my paper based off of the article “Geologic history of the central Mississippi River Valley area in a nutshell” written by Dr. Roy Van Arsdale. Dr. Van Arsdale starts his book off by saying that we often associate the Mississippi River Valley with the adventures of Lewis and Clark, through Mark Twain, and finally to where it is now, expansive farming. He goes on to explain that in order to really understand and grasp all that the Mississippi River Valley has to offer we must first look back into its history which goes back billions of years. Erosion has begun to eat away and remove rocks as well as the fossils that they contain that have formed throughout the Earth’s history. Which means that there are less and less rock specimens for us to sample and examine from the earlier years and this can be really inconvenient when trying to study and put the Earth’s deep time into the proper order. The plate-tectonic theory plays a huge part in the beginning years and it tells us that continents as well as ocean floors have rigid plates in the lithosphere and these plates slide over deeper rock in the asthenosphere. The movement of these plates causes breaking and colliding across the globe and this is what in fact formed North America due to all the collisions and then welding together of many smaller continents and some island arcs during the Precambrian time.
Precambrian rocks have three different types of rocks, sedimentary, igneous, and primarily metamorphic in the origin and the majority of the rocks are buried beneath younger rocks. However, these Precambrian rocks have exposed surfaces in the Great Lakes area as well as the St. Francois Mountains located in the southeastern area of Missouri. Granite and rhyolite are what largely make up the St. Francois Mountains and they also underlie a great deal of the Mississippi River Valley. More continents began to collide together around 1.0 Ga and
Precambrian rocks have three different types of rocks, sedimentary, igneous, and primarily metamorphic in the origin and the majority of the rocks are buried beneath younger rocks. However, these Precambrian rocks have exposed surfaces in the Great Lakes area as well as the St. Francois Mountains located in the southeastern area of Missouri. Granite and rhyolite are what largely make up the St. Francois Mountains and they also underlie a great deal of the Mississippi River Valley. More continents began to collide together around 1.0 Ga and