Sunday, July 13, 2008

Arches National Park

In the southeast region of Utah is a place of mysterious landforms; turquoise soil, balanced rocks, and stone arches. The arches are the namesake of this place; Arches National Park. Flat Stanley arrived at the park late in the afternoon, which was both good and bad. The late start meant most of the park went unexplored, but the late-day sun really showcased a magnificent display of colors.

The geologists are a little puzzled over exactly how many of the arches were formed. One key may be salt. At one time, it is suspected that this area was covered by an ancient salty sea. Below the sandstone surface are huge salt deposits, thousands of feet thick in some places, which were formed as the sea evaporated. Once dry, debris from erosion of surrounding lands accumulated in the valley of the former sea. Add lots of time and more erosion debris, and you eventually get sandstone. The problem is that salt is not inherently stable building material. So when the opportunity presented itself, the salt, mixed with a little groundwater, flowed from on spot to another like when you squeeze a tube of toothpaste. The rock above fell in some areas and rose in others. This shifting ground is suspected to have provided cracks in the sandstone that accelerated the erosion process. Sometimes there were stress concentrations that fractured the rock below the surface. These weakened locations eroded away, leaving intact a stone bridge or arch. At least, that’s the theory.

Relatively close to the entrance to the park is a formation known as the Three Gossips. At the time we got to the park, the sun was near the “heads” of the Gossips. Flat Stanley believes that a better name may be the Three Kings, particularly at that time of day, referencing the Biblical story of how three kings followed a star to see the baby Jesus.

The Delicate Arch is probably the park’s most famous arch. In fact, this arch is on the Utah license plates.

Much of the surface of the ground here is covered with a bumpy, dark brown crust known as cryptobiotic soil crust. The cryptobiotic skin is made up of cyanobacteria, mosses, soil lichens, green algae, microfungi, and bacteria. This skin helps make it possible for other plants to live in the desert by depositing nitrogen from the air into the soil, providing a safe haven for seeds, and providing resistance to the forces of water and wind erosion.

The Three Kings/Three Gossips

Delicate Arch

Valley View

Landscape Arch

Valley View

Balanced Rock

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