Mount Rushmore, also known as the Shrine of Democracy, is a National Monument and Memorial depicting four of the most prominent presidents of the first 150 years of the United States – George Washington, Abraham Lincoln, Teddy Roosevelt, and Thomas Jefferson. Mount Rushmore was carved into South Dakota’s Black Hills from 1927 to 1941 under the direction of sculptor Gutzon Borglum. The project took a team of 400 drillers and assistant carvers fourteen years to complete. Over 800 million pounds of stone were removed using dynamite, detailed drilling, and finishing processes.During your visit to Mount Rushmore, walk the Presidential Trail to the base of the mountain where you just might see mountain goats, enjoy the Avenue of Flags, browse the gift shop and spend time at the interactive museum and visitor center.
History & Culture of Mount Rushmore
Mount Rushmore National Memorial is host to almost three million visitors a year from across the country and around the world. They come to marvel at the majestic beauty of the Black Hills of South Dakota and to learn about the birth, growth, development and the preservation of our country. Over the decades, Mount Rushmore has grown in fame as a symbol of America-a symbol of freedom and hope for people from all cultures and backgrounds.All the cultures that make up the fabric of this country are represented by the memorial and surrounding Black Hills. One of the most important gifts we can give our visitors at Mount Rushmore National Memorial is an understanding and love for our nation’s history and cultures and an appreciation of the importance of caring for that legacy.
Ecology of Mount Rushmore
The flora and fauna of Mount Rushmore are similar to those of the rest of the Black Hills region of South Dakota. Birds including the turkey vulture, bald eagle, hawk, and meadowlark fly around Mount Rushmore, occasionally making nesting spots in the ledges of the mountain. Smaller birds, including songbirds, nuthatches, and woodpeckers, inhabit the surrounding pine forests. Terrestrial mammals include the mouse, chipmunk, squirrel, skunk,porcupine, raccoon, beaver, badger, coyote, bighorn sheep, and bobcat. In addition, several species of frogs and snakes inhabit the region. The two streams in the memorial, the Grizzly Bear and Starling Basin brooks, support fish such as the longnose dace and the brook trout. Mountain goatsare not indigenous to the area but can also be found here. They are descended from goats which were a gift from Canada to Custer State Park in 1924 but later escaped.At lower elevations, coniferous trees, mainly the Ponderosa pine, surround most of the monument, providing shade from the sun. Other trees include the bur oak, the Black Hills spruce, and the cottonwood. Nine species of shrubs live near Mount Rushmore. There is also a wide variety of wildflowers, including especially the snapdragon, sunflower, and violet. Mount Rushmore is a Adventure Place For Vacations. Towards higher elevations, plant life becomes sparser. However, only approximately five percent of the plant species found in the Black Hills are indigenous to the regionThe area receives about 18 inches (460 mm) of precipitation on average per year, enough to support abundant animal and plant life. Trees and other plants help to control surface runoff. Dikes, seeps, and springs help to dam up water that is flowing downhill, providing watering spots for animals. In addition, stones like sandstone and limestone help to hold groundwater, creatingaquifers.Forest fires occur in the Ponderosa forests surrounding Mount Rushmore around every 27 years. This was determined from fire scars in tree core samples. These help to clean forest debris located on the ground. Large conflagrations are rare, but have occurred in the past.
Geology of Mount Rushmore
Mount Rushmore is largely composed of granite. The memorial is carved on the northwest margin of the Harney Peak granite batholith in the Black Hills of South Dakota, so the geologic formations of the heart of the Black Hills region are also evident at Mount Rushmore. The batholith magmaintruded into the pre-existing mica schist rocks during the Precambrian period about 1.6 billion years ago. Very coarse grained pegmatite is associated with the granite of Harney Peak. The light-colored streaks in the presidents’ foreheads are due to these dikes.
The Black Hills granites were exposed to erosion during the late Precambrian, but were buried by sandstones and other sediments during the CambrianPeriod. The area remained buried throughout the Paleozoic Era, but was exposed again to erosion during the tectonic uplift about 70 million years ago. The Black Hills area was uplifted as an elongated geologic dome. The subsequent natural erosion of this mountain range allowed the carvings by stripping the granite of the overlying sediments and the softer adjacent schists complete travel information. The contact between the granite and darker schist is viewable just below the sculpture of Washington.Borglum selected Mount Rushmore as the site for several reasons. The rock of the mountain is composed of smooth, fine-grained granite. The durable granite erodes only 1 inch (25 mm) every 10,000 years, indicating that it was sturdy enough to support sculpting. The mountain’s height of 5,725 feet (1,745 m) above sea level made it suitable, and because it faces the southeast, the workers also had the advantage of sunlight for most of the day.
