Study Guide Chapter 15

1. What processes does gradation include.

2. Describe erosion and deposition.

3. List the gradational agents. What are the energy sources for the gradational agents?

4. Describe the two basic types of weathering.

5. What contributes to the mechanical disintegration of rocks? How?

6. Explain how gradation and tectonics shape the earth's landscape.

7. Explain weathering by the process of frost wedging, salt wedging, exfoliation, and weathering by organic activity.

8. What are evaporites?

Study Guide Continued

9. Explain the weathering process of solution, oxidation, and hydrolysis.

10.What is the most outstanding examples of differential weathering?

11.Describe climatic conditions which speed up chemical weathering rates.

12.Describe slump, mudflow, landslide, rockslide, and rock fall.

13.Define regolith.

14.Compare and contrast slow mass movement and rapid mass movement.

15.Diagram and explain the mass movement process of "creep."

Gradation, Weathering and Mass Wasting

• Gradation– Erosion: Removal of material– Deposition: Filling of depressions– Transportation of materials

• Gradational agents– Water, wind, ice– All agents are powered by solar radiation and

gravity

Weathering

• Material decomposed to prepare for easy transportation

• Types of weathering– Physical/Mechanical

• Disintegrates rock without altering chemical composition.

– Chemical • Rocks decay by a variety of chemical reactions.

Fig. 15-1, p. 424

Weathering

• Rounded rocks- chemical

• Jagged angular rocks- physical

Weathering factors

• Structure and composition of the rock

• Climate

• Configuration of the land surface

• Vegetative cover

Physical Weathering

• Frost wedging– Water freezes in cracks of rocks. When water freezes it

expands. Predominately occurs above the tree line. Figure 15.11 shows talus cones

• Salt wedging– Formation of crystals. Predominately occurs on rocky

marine coasts

• Exfoliation– Peeling off of concentric layers. Half Dome in

Yosemite Valley

exfoliation

Contributors to Physical Weathering

• Joints and fractures in the rock

• Plants

• Animals

• Human activities

Chemical Weathering

• New minerals form finer softer material. Easier to transport.

• Forms– Addition of water– Addition of a weak acid

• Factors that affect chemical weathering– High temperatures and water available– What climate is this?

Hot Humid

Tropical Rainforest

Hot Humid

Tropical Rainforest

chemical

Physical

Chemical Weathering

• Minerals dissolved in water are said to be in solution.

• Mineral salts immediately soluble in water are called evaporites. They precipitate when the water becomes saturated with them.

• Oxidation- Chemical union of oxygen with another substance. Examples- limestone turns yellow or formation of red from iron oxide.

• Hydrolysis- Chemical union of water with another substance.

Some Facts

• Grand Canyon most outstanding feature of differential weathering.

• Regolith-Weathered surface material that covers bedrock.

Regolith and Bedrock

Rapid Mass Movement

• Rapid Mass Movement is visible and dramatic.

• Slump- Curved backward rotation. Frequent in clay rich California.

• MudFlow- More fluid than earth flow. Associated with fires and then torrential rains or volcanoes where the mudflow is called a lahar.

Fig. 15.29

Rapid Mass Movement

• Landslide-Mass of material that moves as a unit. Carries regolith and masses of bedrock. Conditions: Steep mountains and heavy rain or earthquakes.

• Rockfall-Individual rock or several rocks that fall down slope. Rock fragments can be small or large.

Rockfall

Slow Mass Movement

• Creep

• Solifluction– Thawed area of permafrost. What biome?– Unfrozen part of the soil becomes watersoaked

creating a soggy mass that sags slowly downslope in response of gravity.

TundraTundra

CreepTilted Telephonepoles

Broken walls Curving plant growth

Figs. 15.31 &32

Solifluction