Explain why a glacier has a U-shaped cross section, whereas mountain stream valleys are usually V-shaped
What will be an ideal response?
Erosion of valleys in mountains is caused by downward erosion by flowing water in a narrow channel. As the resulting valley walls become very steep, they fail during mass movements, which deliver debris to the stream to be carried away. Therefore, stream valleys have a V-shaped cross section with sloping hillsides descending to the stream channel. When a glacier flows through a pre-existing valley, it erodes not only at the bottom but also along the sides of the valley. The shear stress exerted against the sides and bottom of the valley erodes rock in a fashion analogous to an ice-scream scoop moving through ice cream, which leaves a broad-floored, steep-sided, U-shaped cross section.
You might also like to view...
The multiple nuclei theory recognized that
A) cities grow. B) residential areas are racially segregated. C) cities develop around several nodes. D) urban sprawl has developed in cities.
In the deep ocean, tsunami waves will travel at speeds approaching ____ km/hr
a. ?1 b. ?25 c. ?100 d. ?900 e. ?5,000
The boundaries between the distinct layers found in many sedimentary rocks are called ____
a. foliation b. outcrops c. rock cycles d. bedding planes
An oceanic trench is a deep narrow rift parallel to the crest of a mid-oceanic ridge.
Answer the following statement true (T) or false (F)