Not all Buttes are the Same

The Palouse is known for its vast, rolling farm hills that are really hard to miss when traveling in south-eastern Washington State. These hills hold the heart of most of the states agricultural farming, specifically wheat and lentils. However, as you travel your way around the town of Palouse and Albion, you may notice a hill that seems to stick out over the rest. Kamiak Butte is one of the many buttes found in this part of the state, and they all stand clearly over all the other hills found around the Palouse. But why do these random masses of land stand out? There is a simple, yet very interesting reason why.

Kamiak Butte stands out from the other surrounding hills of the Palouse due to the placement of Precambrian rocks that do not erode fast and therefore remains where it is while slowly have Columbia River basalt and losses moves in, causing a buildup of material to rise high above the rest of the Palouse Hills. Buttes can take different forms depending on the terrain, rock in the area, and what caused the formation. Sandstone buttes are very common, but since there is no sandstone in this part of the country, so instead it is a different formation. Instead of a random rock formation, buttes in Washington look like really tall hills covered in trees, where the rest of the Palouse hills have very few trees due to all the fields, as can be seen in Figure 1 in the images above.

Kamiak Butte, specifically, is made up of mostly two types of rock: quartzite, possibly from around the time of the Cambrian era, and a mix of undivided agrilite, siltite and phyllite. The latter listed rock comes from the belt supergroup, a group of rock that was formed the earliest out of all the rock types at the beginning of the formation of this part of North America, so it is some of the oldest rock you can find in this part of the state. The quartzite found at Kamiak, although not completely confirmed to be from the Cambrian era since these data have not been published (Ellis et al., 2004), was formed up to 540 million years ago, therefore being newer, but still really old rock found out in the open, especially since there have been traces of phyllite, like the type found in the undivided mix. These rock types make up separate halves of Kamiak, as shown in Figure 2 above, where the two types of rock share halves of the butte up to the point, as well as a portion that is made up of landslide deposits that is now completely covered in trees.

Now we get to the reason why these old rock types are showing and towering over the rest of the hills in the Palouse. The majority of the Palouse, disregarding the buttes, are built off Columbia River basalt. This rock was formed up to 17.5 million years ago (Program, 2017). These flood basalts came in quite recently compared to the other rock types mentioned earlier. As the water level continued to drop revealing more land, a large amount of volcanic activity occurred in that area, causing a large area of Washington, Oregon, Idaho, and a little bit of Nevada, covered in this unique and large spanning basalt, with nutrient-rich material later covering it up and creating the hills of the Palouse. Before these eruptions, the buttes we know today were quite a bit taller than we see them now, especially since their types of rock are very slow to erode. These masses of rock were tall enough that after the basalts and other material set in, there was still quite a big mass of the older rock that couldn't be covered with the most recent rock, forming the buttes, like what is shown in Figure 3. Kamiak Butte stands out compared to the other landforms of the like in that area because of the specific rock layout it is made of, where most buttes usually only show one or different types of rock.

With the variety and age of the rock found at Kamiak, it is a real geologic discovery that deserves some more research. Like what was mentioned before, there isn't enough solid evidence found of the rock types on Kamiak to know specific details about the landform and how it was created. The buttes found in Washington are rare compared to all other types of buttes found across the rest of the earth, so these are really amazing geologic creations on earth. If you ever find yourself traveling down that part of the state of Washington, take a moment to take in the sights of what mother earth has created in the area of the Palouse.