Granite Dells
Encyclopedia
Prescott, Arizona
Prescott is a city in Yavapai County, Arizona, USA. It was designated "Arizona's Christmas City" by Arizona Governor Rose Mofford in the late 1980s....
. The Dells consist of exposed bedrock and large boulders of granite that have eroded into an unusual lumpy, rippled appearance. Watson Lake
Watson Lake (Arizona)
Watson Lake is one of two reservoirs at the Granite Dells, outside of Prescott, Arizona that was formed in the early 1900s when the Chino Valley Irrigation District built a dam on Granite Creek. The City of Prescott bought the reservoir and surrounding land in 1997 to preserve it as recreational land...
and Willow Lake
Willow Lake
Willow Lake may refer to:In the United States*Willow Lake , listed on the NRHP in Georgia* Willow Lake Township, Minnesota* Willow Lake in Flushing Meadows-Corona Park, Queens, New York* Willow Lake, South Dakota...
are small man-made reservoirs in this formation; these, combined with numerous hiking & biking trails and rockclimbing routes, make it a popular outdoor recreation area in the region.
The Peavine National Recreation Trail
National Recreation Trail
National Recreation Trail is a designation given to existing trails that contribute to health, conservation, and recreation goals in the United States. Over 1,000 trails in all 50 U.S. states, available for public use and ranging from less than a mile to in length, have been designated as NRTs...
follows the old railbed of the Santa Fe, Prescott and Phoenix Railway
Santa Fe, Prescott and Phoenix Railway
The Santa Fe, Prescott and Phoenix Railway was a common carrier railroad that later became an operating subsidiary of the Atchison, Topeka and Santa Fe Railway in Arizona. At Ash Fork, Arizona the SFP&P connected with Santa Fe's operating subsidiary, the Atlantic & Pacific Railroad mainline, that...
through the Granite Dells. This winding portion of the railroad was known as the "Peavine" because its twisting curves resembled that of a pea vine. It connects to the Iron King Trail , which follows the route of the old Prescott and Eastern Railroad
Prescott and Eastern Railroad
The Prescott and Eastern Railroad was a non-operating subsidiary of the Santa Fe, Prescott and Phoenix Railway in Arizona. The 26.4 mile common carrier railroad was built to serve the mines in the region. The railroad built from a connection with the SFP&P at Entro and extended south to Poland...
through the eastern Granite Dells. Both are rail to trail conversions.
Geology
The Dells Granite has been dated at 1.4 billion years old. Its plutonPluton
A pluton in geology is a body of intrusive igneous rock that crystallized from magma slowly cooling below the surface of the Earth. Plutons include batholiths, dikes, sills, laccoliths, lopoliths, and other igneous bodies...
was intruded at a depth of around one or two miles (1.6 to 3.2 km). These cover rocks have since been eroded away. Weathering along joints produced the rounded boulders and other unusual rock formations that characterize the Granite Dells. This process is called spheroidal weathering
Spheroidal weathering
Spheroidal weathering is a type of chemical weathering that creates rounded boulders and helps to create domed monoliths. This should not be confused with stream abrasion, a physical process which also creates rounded rocks on a much smaller scale...
, and is common in granitic terrains.
The Dells Granite has an unusually high uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
content, and thus homes built over the granite should be checked for radon
Radon
Radon is a chemical element with symbol Rn and atomic number 86. It is a radioactive, colorless, odorless, tasteless noble gas, occurring naturally as the decay product of uranium or thorium. Its most stable isotope, 222Rn, has a half-life of 3.8 days...
leaking from the granite.