I know that most stories posted by our class relate to natural geological features or instances that affect our geological standpoint. But I though it would be interesting to talk about a geological feature that was developed by man. I am talking about Mount Rushmore, where four gigantic faces are carved into a mountain in South Dakota.
Mount Rushmore is a United States presidential memorial. It has four previous presidents faces carved into it. The four presidents are George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln. All four of theses presidents had an important impact on our country’s development.
The memorial is extremely extensive covering over thirteen hundred acres and is more than fifty eight hundred feet above sea level. The mountain has an interesting past; it was originally named Lakota Sioux or six grandfathers. But it was renamed in 1885 after a lawyer from New York named Charles Rushmore.
The idea and project of carving the four faces into the mountain was developed because tourism in South Dakota needed something to attract people. Once the idea was approved, construction of the Monument began in 1927. The project was finally finished in 1941. The construction was very dangerous, but there were no deaths.
Mount Rushmore is almost completely granite and lays particularly in the Black Hills of South Dakota. Pre-existing mica schist contains intrusions of batholith magma from the Precambrian period. Some minerals that the mountain contains are quartz, biotite, feldspar, and muscovite. One unbelievable fact is the Black Hills once stood 20,000 feet, but due to erosion shrank to 4,000 feet. Also an important geological feature that the mountain contains is extremely smooth granite. The fine grained granite made Mount Rushmore a great choice for the sculpture. Also granite normally only erodes one inch every ten thousand years.
Mount Rushmore has made tourism South Dakota’s second largest industry. On average two million people visit the monument every year.