Independence Rock Geology

Independence Rock

Independence Rock, located in modern-day Wyoming, was the second big monolith the emigrants came across on their journey from the east. If you’ve ever gone on a long trip, you know how important timing is. Maybe you know you have to be at the airport two hours before your flight, or you have to drive to Omaha by noon. Of course, what takes us a few hours in an airplane took the emigrants about six months to walk. Timing was just as important for them: too early and there wouldn’t be enough grass for the animals; too late, and travelers risked death by blizzard in the Sierra Nevadas. Independence Rock was one of the ways they would know if they needed to hurry up.

Independence Rock is what geologists call a “pluton:” a big body of igneous rock (in this case, a granite that is over one billion years old) that cooled slowly under the surface of the earth and then was slowly exposed by erosion of the surface layers. It is more than a mile in circumference and stands up to 136 feet higher than the surrounding areas. It gets its name from its main function on the trail: travelers who weren’t at Independence Rock by Independence Day were lagging behind, and in danger from possible bad weather in the mountains ahead.

Sitting as it does by the pleasant Sweetwater River, Independence Rock was a popular place for emigrants who had made good time to take a little rest. Many of them carved their names into the wind-polished surface, and today it serves as kind of record book.

For more information on Independence Rock, you can visit http://wyoparks.state.wy.us/Site/SiteInfo.aspx?siteID=24