Two very different types of landscapes occur in Arizona: the Basin and Range Province of southwestern Arizona and the Colorado Plateau Province of northern Arizona. Between them lies the Transition Zone.
U.S. Highway 93 from Wickenburg to Wikieup (the Joshua Tree Forest Highway) provides a fine example of the Basin and Range topography and the beginning of the Transition Zone as you head north to Nothing. And yes, Nothing was an Arizona town! It is still marked with a sign and piles of…..well, junk. But there really is something that is worth seeing in Nothing. Here, granite rocks begin to be piled up high on each other, appearing like hoodoos, creating a very interesting sight.
These granite outcroppings resulted from the upward thrust of rock lying deep within the core of the earth. Underground earthquakes and volcanic eruptions that occurred millions of years ago pushed these boulders to the surface. Technically, this granite is called “Granitis Gneiss”. Gneiss (pronounced “nice”) is formed when the granite has been subjected to extreme pressures and temperatures. The resulting crystallization of the granite becomes a colorful mix of minerals, such as quartz (clear pink and white), feldspar (pink and red), mica (dark brown), and amphibole (black).
To receive credit for this earthcache, email to me the answers to the following questions:
1. Describe the composition of the granite boulder in front of you by naming its colors and corresponding minerals.
2. What formed this landscape of piled up rocks?
3. Why do you think there are so many cracks in the granite boulders?
4. What is the elevation at this spot?