The Arches

Before I begin my discussion of the park, perhaps a short lesson in geology is appropriate. All of Utah was once part of a great sweeping desert in the early Jurassic, an series of steadily rolling dunes great enough to bury our own contemporary Sahel. These endless sandy dunes would form the mottled grey sandstone of the Navajo formation that underlies the park and much of the Colorado Plateau. A broad, shallow river would eventually wend its way between the dunes through the heart of this ancient desert, pushing slow rippled layers of yellowed silt into what would become the sandstone of the lower Entrada. It would be followed by the iron-tainted silica that gave the sandstone of the upper Entrada its warm red tint. Collectively, these strata are known as 'slickrock', and it is within these layers that we find the arches of the eponymous park.

I love slickrock. As it is built of fossilized sand-dunes, it has amazing traction, and I could run and jump carefree up and down their weird slopes all day long. That said, when wet, slickrock can truly earn its name - and it also occasionally peels off of the basal strata in small narrow sheets, like subscription cards falling from a magazine. If one is not careful, you might find yourself suddenly slipping down the hillside as your footing dances out from beneath you, and a spill upon slickrock is akin to dragging oneself along five or six feet of low-grade sandpaper. One learns to listen for a hollow drumming sound as you put your foot down, as this indicates a sheet eroding away from the main body... but frequent visitors bear the broad pink scars of their road rash as a masochistic badge of pride.

On our way into the park, we pass a small group of female and juvenile bighorn sheep grazing on the side of the the road. As the road into the park is surprisingly busy, and as I had expected them to be more prevalent within the park, we did not photograph them. I now regret that we did not stop to photograph the small herd, as they are far more uncommon than presumed. They are rare and secretive animals, usually avoiding the bustle of humanity, and this was to be our only encounter with the ungulates for the whole trip.

Park Avenue First we visit a 'short and easy hike' down Park Avenue, featured prominently in the opening of "Indiana Jones and the Last Crusade". We do not bring water, as this is to have been a short hike... but the erosion plane just keeps drawing us forward, on to better and better vistas. We make it to the bottom, and almost to the far road before we finally turn back. After jumping in the car (and turning on the air conditioning), we look at my blotchy red face and hereby swear to never leave the vehicle without at least one water bottle again.

The Windows

Arches are anticlinic layers (standing like a book on their spine) of sedimentary rock interrupted by layers of salt and gypsum; this allows variable erosion rate and acids to build up at base of cracks to create great stone 'fins'.

Arches occur through a two-step geological process. First, the rocks are exposed and cracked, forming long 'fins' of sand. Then the sandstone layer at the base of the fin must erode at a higher rate than the stone lying above it. This process is aided by washed-off acids that accumulate at the bases of fins. These acids help to break down rocks in the center, and this uneven erosion is further aided by wind and water action. Once a hole in the middle begins, it is only a matter of time before it disintegrates outward, as rocks continue to fall from the center of the arch.

This matter of time may take thousands of years.

The windows are impressive.

A lot of other people here, getting in the way of my photos, so I do not take as many as I would like.

Arch View

We've been too long in the flatlands, and believe ourselves too tired out to tackle the 'arduous' trail to the Delicate Arch, and opt to get a taste of tomorrow's fun by previewing it from a distance. We climb to the top of a short hill, and notice that while hiking all day, we have overheard a LOT of German-speaking tourists. I suspect that it is an invasion, but they seem friendly, so we let them be.