The Menan Buttes are two extinct volcanoes in Menan, Idaho. Menan is part of the Idaho Falls metropolitan area. The two buttes are called North Menan Butte and South Menan Butte. The Menan Buttes are tuff cones, which form when water and basaltic magma come into contact with each other.
These unusual land masses are from the late Pleistocene Epoch, which was a period that lasted from 5 million years ago until 10,000 years ago. The Menan Buttes formed about 10,000 years ago when magma erupted through the Snake River's cold water. The rapid cooling crystallized the magma into volcanic glass.
North Menan Butte is the larger of the two. The summit of North Menan Butte reaches 5,230 feet above sea level. North Menan Butte is 0.16 cubic miles in volume, while South Menan Butte is 0.07 cubic miles. The cone of North Menan Butte is about 6,000 feet wide, has a crater 3,000 feet wide and rises about 800 feet higher than the land that surrounds it.
The deposits scattered amid the Menan Buttes are made of a volcanic glass called tachylite. The unusual climate and terrain of the buttes can support vegetation that is not commonly found in the area, such as Douglas fir and aspen. A variety of animals also call the area home, including hawks, falcons, owls and eagles. Ground squirrels, jackrabbits and fish also have habitats in this territory.
Tourists can see unusual formations caused by the winds that usually blow from the southwest. The strange shapes caused by the solidified magma bubbles are also a popular attraction. In addition, visitors can spot xenoliths, which are rocks embedded in magma that has cooled and become solid.
The Menan Buttes are the only examples of freshwater volcanic eruptions in the United States. The buttes are also two of the largest tuff cones in the world. The United States National Park Service chose North Menan Butte as a National Natural Landmark. Admission is free. The buttes are also part of an Area of Critical Environmental Concern, which is intended to keep the location unaltered and preserved for future generations.
Tourists should bring a lot of water when visiting the Menan Buttes because the climate is often arid and hot. Visitors are not allowed to deposit any trash or remove anything from the site. Also, motor vehicles are not allowed because they can destroy vegetation and cause erosion. Beware of snakes, slippery rocks and loose rocks.
