1. The huge dust storms on deserts can carry tons of sediment into the atmospher
ID: 291786 • Letter: 1
Question
1.
The huge dust storms on deserts can carry tons of sediment into the atmosphere. When these sediments finally settle out of the air the deposit they create is called...
fan dust
loess
silt
foo-foo dust
2.
This is a picture of the desert floor outside of Bouse, AZ. This naturally broken rock nicely illustrates the thinness of its desert varnish. How does desert varnish form on rocks?
There is a constant "rain" of dust rich in iron and magnesium falling out of the atmosphere all of the time. In deserts, the lack of rainfall allows this dust to accumulate on rocks and create the varnish. Elsewhere, this dust is simply washed away.
The intense heat and sunlight bake the surface of the desert rocks. Over thousands of years the more volatile minerals are removed leaving only those minerals that are rich in iron and magnesium
It is created by the very dry desert environment leaching any small quantities of water that may be in the rocks. As this water is leached out it deposits the minerals that were dissolved in it. As the water evaporates, the minerals (primarily iron and magnesium) remain as a thin coating on the rock.
Clay settles out onto the rocks on the desert floor. Bacteria then "fix" (stabilize) the clay to form a thin coating of iron and magnesium.
3.
The White Tank Mountains make up the western border of the Valley of the Sun. Why are they called the White Tank Mountains?
During WWII, General Patton placed several discarded tanks in these mountains for target practice. They were painted white to be easily visible from the desert rocks. Some of the tanks still remain and gave the mountains their name.
The mountains have abundant outcrops of white gypsum which were mined in the early 1940's for use in the manufacture of paint for tanks as well as in the manufacture of tank tracks.
They have white colored tanks along the stream beds in the mountains. These light colored are as are where stream erosion has removed the dark colored desert varnish and prevents it from forming.
The mountains consist of a very light colored granite and some boulders looked like tanks to the early settlers.
4.
Alluvial fans consist of sediment that are commonly...
composed of angular fragments
All of these answers are correct.
poorly sorted
commonly the result of flash floods
Explanation / Answer
1-The huge dust storm on dessert can carry lots of sediments into atmosphere. When these sediments finally settle out of the air, the deposit they create is called loess.
Loess is a silt sized sediments deposition that is formed by the accumulation of wind blown sediment or dust.it may be form in the atmosphere or also on the surface of the Earth .it is contain 20% clay and balanced equal percentage of sand and silt.
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