Salt
weathering created the sandstone arches in Arches National Park. Salt
weathering is a combination of mechanical and chemical weathering. Using the bad diagram from class I can
show the mechanical weathering of frost wedging from water making its way in
between the joints, cracks and other physical feature and breaking away the
sandstone over time. Also over time wind and water would clean out the
sediment. The only problem with
this bad diagram is the wind is “wimpy” and can’t exert enough force to blast a
hole in the wall of sandstone, so part 3 of the diagram is wrong. For the
second part we bring in chemical weathering specifically the dissolution of the
cemented material by carbon dioxide and water making carbonic acid. When the carbonic acid reacts with the
calcium carbonate in the soil then it makes calcium bicarbonate. Chemically
written out (from lecture)
Most
of the soils in this region are under the classification of Aridsols. This being said the other type of soil
is biological crust; this is living groundcover mosses, green algae, micro
fungi, and bacteria. It is
estimated by some that they are over 2 billion years old and some uses are to
trap and disperse water, bind soils together, and fix atmospheric nitrogen in
the soil. This is important for
Arches National Park to understand because it will lead to better land use
practices and decreases the effect of tourism in the area. (soil information
taken from soil lecture and http://www.nps.gov/arch/naturescience/soils.htm
)
Sources
Bad
diagram is from class lecture along with chemical formula
Rock
fins picture
Soil
close up picture
Seedling in biological soil crust
NPS Photo by Neal Herbert
soils
paragraph based off of in class soils lecture and http://www.nps.gov/arch/naturescience/soils.htm
