Ch.5 Survey

When does mechanical weathering occur?
Occurs when physical forces break rock into smaller and smaller pieces without changing the rock’s mineral composition.
Name the three physical processes that causes mechanical weathering.
Frost wedging, unloading, and biological activity.
Describe frost wedging.
The mechanical breakup of rock caused by the expansion of freezing water in cracks and crevices.
Slabs of outer rock separate like the layers of an onion and break loose in a process called….
Exfoliation
What is meant by biological activity?
Explain chemical weathering.
Is the transformation of rock into one or more new compounds.
What is the most important agent of chemical weathering?
Water
Can chemical weathering change the physical shape of a rock?
Yes
What two factors affect the rate of weathering?
Rock characteristics and climate.
Give an example of a rock characteristic?
Cracks in rocks.
What is regolith?
Weathering produces a layer of rock and mineral fragments.
Name the 4 major components of soil.
Mineral matter, organic matter, water, and air
What are the most important factors in soil formation?
Parent material, time, climate, organisms, and slope.
Soil varies in composition……, ……., and ……… at different depths.
Texture, structure, and color at different depths.
What are the three common types of soil?
Pedalfer, pedocal, and laterite
How do human activities affect rates of erosion?
They remove natural vegetation, such as farming, logging, and construction
What is mass movement?
The transfer of rock and soil down slope due to gravity.
What triggers mass movement?
Are saturation of surface materials with water, over steepening of slopes, removal of vegetation, and earthquakes
How do geologists classify mass movements?
Based on the kind of material that moves, how it moves, and the speed of movement.
When does rockfall occur?
When rocks or rock fragments fall freely through the air.
How do mudflows differ from earthflows?
Mud flows are flows that moves quickly and Earth flow are flows that moves slowly.