The creation of Arches came down to the geologic ingredients in the National Park. In his latest video, YouTuber National Park Diaries broke down how the many formations at Arches came to be. He discussed three areas in particular: the Salt Valley, the rock fins, and the actual Arches.
Around three hundred million years ago, Utah dealt with nearly thirty cycles of ocean waters advancing and receding, leaving behind a plentiful amount of salt. This is referred to as a paradox basin, where this salt has no outlet to depart, and thus evaporates into the surface, leaving behind lots of sodium chloride. Millions of years later, the growing mountains caused erosion from rainfall, carrying sentiment away to be deposited somewhere. This is called deposition.
This deposition led to rocks on top of the sodium chloride that was formed millions of years earlier. The vertically fissured rocks were broken down and eroded by the salt, and the NaCl collapsed as well due to rain breaking through the narrowing fissure, leading to the Salt Valley which is situated between the massive rocks.
On the edges of the Salt Valley are the remaining vertical fissures. These were formed by dealing with slightly acidic rain and being exposed to the surface, widening the fissures and cracks, and leading to fins eventually forming.
The National Park is full of Entrada sandstone, which has lots of pores, leading to changes. Below the Entrada Sandstone is Carmel Formations, which contain a lot of clay. These have fewer pores, meaning that water eats away from the top of the Entrada Sandstone rock, leading to these arches.
For a more comprehensive breakdown from someone who actually knows what he’s talking about, the video from National Park Diaries is below.
Image/Video Credits: Ken Cheung (Featured Image), Canyonlands Natural History Association, National Park Diaries
