Fins - Arches National Park, Moab, Utah

There is something about the rock formations in the American Southwest that always makes me wonder how they were created. Of course, the answer is usually erosion, but it is hard to put my head around it. Whenever I see the many different and unusual ones, usually in close proximity to one another, I think of what combination of wind, water and ice made each the way they are, especially since they were exposed to very similar conditions over time. On the opposite hand, there are rock formations like these sandstone fins that have a very similar shape as far as the eye can see. 

I decided to find out how these fins were created and here is what I found out. Fins are actually an intermediate stage in the erosion of sandstone. The fins may have started out as part of a plateau. Through the uplift of the underlying rock, deep vertical, parallel fractures to begin to be formed. Weathering and erosion enlarge the fractures and the sandstone falls away until they form the shape that you see in this photo.

What's next for these fins? The next stage is the erosion of sandstone below forming either windows or arches. Over time, even these erode causing the arches to collapse, resulting in hoodoos. This helps me understand how the rock formations in Arches National Park were formed.