The Beauty of Sandstone and Sandstone Formations

 

Nature has a wonderful way of creating beautiful scenery that humans can only wish to imitate and can only come close in comparison. The sedimentary rock formations of sandstone are just one example of these many natural beauties. Created by erosion of other rocks and minerals, igneous and metamorphic rock, and other sedimentary rocks; these rocks form over time as pressures and temperatures compress these smaller particles into these colorfully beautiful formations.

 

Coyote Buttes

 

Found in Utah and Arizona, these sandstone formations are part of Coyote Buttes. Coyote Buttes is just a small part of Paria Canyon - Vermilion Cliffs Wilderness which is protected by the U.S. Bureau of Land Management (these photos are from their site http://www.blm.gov/az/st/en/arolrsmain/paria/coyote_buttes.html).

 

 

 

Arches National Park - Utah

 

Another location where sandstone formations leave visitors in awe is the Arches National Park in Utah. The sandstone in Arches National Park gets its bright red color from iron deposits in the sandstone. These iron deposits have been exposed to oxygen which has caused them to "rust", creating the beautiful red hues. The photos were taken from National Park Services' web site (http://www.nps.gov/media/photo/gallery.htm?id=221F3BB7-155D-451F-6738DBB434CFBF5E).

 

 

One of the arches from the park provides a beautiful addition to a photo which captures part of the Milkyway Galaxy.

 

This illustration from the National Park Services, shows how these arches formed over time. The following is their description of how these formations were created.

 

"First, you need the right kinds of rock.
Sandstone is made of grains of sand cemented together by minerals, but not all sandstone is the same. The Entrada Sandstone was once a massive desert, full of shifting dunes of fine-grained sand. The grains are nearly spherical so, when packed together, they formed a rock that is very porous (full of tiny spaces).

In contrast, the Carmel layer just beneath the Entrada contains a mix of sand and clay. Clay particles are much smaller than sand grains; a lot of them can pack together and fill in gaps between the sand grains, making the rock denser and less porous than a purer sandstone.

Crack it into parallel lines.
Deep beneath the surface lies a thick layer of salts. Squeezed by the tons of rock above it, the salt flowed and bulged upward, creating long domes. The rock layers covering these domes were forced to crack, like the surface of freshly-baked bread, into a series of more-or-less parallel lines.

Next, add the right amount of rain.
On average, the park receives 8-10 inches (18-23 cm) of precipitation a year. That might not sound like much, but it's enough to keep the engines of erosion working 24 hours a day, 365 days a year.
Drops of rainwater soak into the porous Entrada sandstone easily and then slowly dissolve the calcite bonding the sand together – in other words, rotting the rock from the inside out. Water puddles just above the denser Carmel layer where it erodes a cavity, like food trapped between your teeth. In winter, water trapped between the two layers expands when it freezes and pries the rock apart.

If the park received too much precipitation, the sandstone could erode so quickly that arches might not have time to form. If it never rained here, the engines of erosion would stop.

Make sure your rocks don't rock & roll.
Luckily, earthquakes are rare in this area. If the ground shook often, these massive outdoor rock sculptures would splinter and collapse. The fact that over 2,000 still stand, waiting for visitors to discover them, tells us this area has been rather geologically stable for at least 50,000 years.

Lastly, pick the right time to visit. (You did.)
The rock layers visible in the park today were once buried by over a mile of other rock that had to erode first to expose what lied beneath. Visitors one million years ago might have seen an endless flat plain dotted with vegetation. Imagine a visit 100,000 years in the future, when the Entrada and Carmel layers have fully worn away. What new rock shapes might you discover then? (Source, National Park Services - http://www.nps.gov/arch/learn/nature/geologicformations.htm)