Internal/External Processes Flashcards
What is the internal process?
Building up the landscape. Derive energy from with in Earth’s int. (Magma)
What is the external processes?
Wear down the landscape. Derive energy from outside of Earth’s int.
Breaking down rocks is either or of what three processes?
Physical, chemical, or biological processes.
What is the biological process?
Takes place “in situ” Weathering takes in place of the process itself. Causes cracks, features, and joints accelerate inside rocks.
What is physical weathering?
Disintegration (breaking down) of rocks without chemical alteration.
Physical weathering causes what three events?
Frost wedging, salt wedging, exfoliation
What is frost wedging?
Prob the most important single agent of weathering. When causing ice crystals this also causes expansion of water volume by 9%! WOW! Ex.) Talus Slope, Mt. Rushmore, Mt. Cliffs.
What is salt wedging?
Development of salt crystals. Ex.) Coastlines, Avid deserts-dry lakes=playas (flat dry land)
What is exfoliation?
When a granite batholith is faulted to the surface and exposed, the pressure is released and the outer layers of rocks expand. Causes pressure release joints and a fresh face.
When does frost wedging occur?
Occurs in high elevation/high latitudes.
When does salt wedging occur?
Occurs in these environments.
Exfoliation causes what two events?
Pressure release joints and a “fresh face”
What is pressure release joints?
The release of pressure cases the rock to expand and crack in curved layers of rock.
What is pressure release joints also called?
Pressure unloading joints.
What is a “fresh face?”
The curved layers peel off layer after layer exposing the new fresh face.
What does a fresh face result in?
Rock slides, exfoliation domes.
What are talus slopes?
Layers in rock that slowly fall off.
What is chemical weathering?
Disintegration of rock by chemical alteration. It is softer, less resistant to erosion.
What are two chemical weathering components?
Carbonation and oxidation
What is oxidation?
Oxygen combines with certain minerals to form oxides.
What is carbonation?
Carbon dioxide combines with water to form a weak carbonic acid.
What is the most common oxidation?
Iron oxide = rust
What are examples of oxidation?
Grand Canyon, Colorado plateau, red rock canyon in Las Vegas.
Carbonation: What can carbonic acid dissolve?
Calcium carbonate otherwise known as limestone
