Mount Rushmore Granite Geology

The granite is a very hard rock and the mica schist is much softer.

Mount rushmore granite geology. Mount rushmore national memorial is centered on a colossal sculpture carved into the granite face of mount rushmore in the black hills in keystone south dakota sculptor gutzon borglum created the sculpture s design and oversaw the project s execution from 1927 to 1941 with the help of his son lincoln borglum. Long before four of the largest faces on earth were dynamited into the granite edifice of mount rushmore the lakota sioux saw a different set of portraits. What you see today. We ve never seen anything like it.

The light colored rock that you see on the faces is fine grained granite. A huge portion of that quickly cooled rock now forms the upper part of mount rushmore. The granite was once molten rock and the mica schist was formed as a result of the heat and pressure exerted by the molten rock. The less resistant mica schist tends to be eroded into canyons and gullies.

In the area of the memorial the hard granite creates mountains or hills and the equally tough quartzite forms knife ridges. In 1989 the national park service and the mount rushmore society began studies to understand the structure of the mountain itself. The two stories of the rocks at mount rushmore the origin of the rocks and the creation of the current topography are as different as the rock types found here at the mountain. Ancient granite and metamorphic rocks.

The batholith magma intruded into the pre existing mica schist rocks during the precambrian period about 1 6 billion years ago. Mount rushmore is here today because the granite erodes very slowly compared to the surrounding rocks. The sculpture of four famous presidents george washington thomas jefferson theodore roosevelt and abraham lincoln was carved into the granite rock face over many decades. The mountain was known as.

Keystone sd scientists from the harold hamm school of geology geological engineering at the university of north dakota arrived at mount rushmore today to investigate what they say is an unprecedented geological phenomena that could have consequences for the popular tourist attraction once covid 19 restrictions are lifted. Mount rushmore is located in the black hills of keystone south dakota. The sculpture features the 60 foot 18 m heads of presidents george washington. Mount rushmore basically consists of two kinds of rocks.