Midterm Exam

GEOL 454 Midterm Exam
Spring 2009
Name ______________________
1) Briefly describe two processes of chemical weathering. Under what climatic
conditions is chemical weathering most effective?
(10 points)
2) Describe the primary characteristics of each of the three basic soil horizons (A, B,
C horizons) in terms of organic matter content, color, texture, structure, and
weathering products. What processes dominate each soil horizon? What controls
do the primary characteristics reflect?
(15 points)
1

3) Slides, flows, and falls are the three main types of rapid mass movement. Explain
the differences among these three in terms of how material moves down slope,
and the deposits that result from each type of movement.
(10 points)
4) Explain why hillslopes in humid regions are more likely to have an angular,
segmented profile, whereas hillslopes in humid regions are more likely to have a
smoothly rounded profile. (Think about relative rates and products of weathering
and types of mass movements.)
(10 points)
2

5) What conditions promote high drainage density and sediment yield?
(10 points)
6) Water flowing downstream in a channel is converting potential energy to kinetic
energy. Describe the three basic ways in which this energy is expended.
(10 points)
3

7) Braided rivers are typical of arid regions and of valleys downstream from
glaciers. Describe the characteristics of braided rivers in terms of channel
planform, channel migration, and floodplain stratigraphy. Do lateral or vertical
accretion deposits dominate the floodplains of braided rivers?
(15 points)
8) Briefly describe three mechanisms that could create terraces along a river.
(10 points)
4

9) Explain the four basic pathways by which water can move down a hillslope, and
the controls on these pathways.
(10 points)
5