Earth Science - Chapter 3 Weathering & Erosion
In a well-developed soil profile the ____ horizon is the topmost layer.
O
The rate of weathering increases in areas with high pollution. (T/F)
True. Pollution contributes to acid rain and accelerates the chemical weathering process.
External processes are responsible for transforming solid rock into sediment. (T/F)
True. Rocks are cohesive units and sediment is loose detritus.
Slope orientation affects the amount of sunlight and the extent of soil formation. (T/F)
True. The amount of sunlight varies when comparing north and south facing slopes and this affects temperature, moisture, and plant growth.
Water expands when it freezes. (T/F)
True. When solid materials expand (ice, clay minerals), this can cause mechanical weathering.
Removing vegetation can increase the rate of soil erosion. (T/F)
True. Without the roots from vegetation there is often little to hold the soil in place from erosional agents.
Erosion can influence and reduce the effectiveness of ______.
agricultural practices; water quality; flood control land use
Which of the following processes contributes to the breakdown of rock material? mass wasting; erosion; weathering
all of them
The atmospheric gas that forms a mild acid when dissolved in water is _______.
carbon dioxide
Which of the following statements is NOT true about mechanical weathering? breaks rock material into smaller pieces; changes chemical composition of rock; creates new compounds
changes chemical composition of rock; creates new compounds
When a rock is subjected to ________, it breaks into smaller pieces having the same characteristics as the original rock.
mechanical weathering
Iron-rich minerals and metals exposed to atmospheric conditions are most likely to weather through a process called _______.
oxidation
The rate of weathering depends on _______.
particle size; composition; atmospheric conditions
Rocks with inclined surfaces of weakness are most likely to experience which type of mass wasting?
rockslides
Which of the following is NOT a form of chemical weathering? root wedging; hydrolysis; oxidation; dissolution; decomposition
root wedging
This type of mechanical weathering process is commonly found associated with igneous rocks as overlying rock material is eroded away.
sheeting
When a mass of material moves downslope along a curved surface the process is called _______.
slump
Frost wedging is most pronounced or effective in mountainous areas and this weathering process contributes to the formation of large piles of rocks called ______ at the base of steep rocky cliffs.
talus slopes
Which of the following is NOT considered a mobile agent? flowing ice; ocean waves; running water; blowing wind; temperature
temperature
The energy for external processes comes primarily from ____.
the Sun
Events that can weaken a slope, increase instability, and can initiate downslope movement are called ______.
triggers
Which of the following is NOT directly related to external processes? wearing away of mountains; volcanic activity; movement of sediment from high to lower elevations; changing desert features; sediment deposition
volcanic activity
Chemical weathering will be most rapid in ___________ climates.
warm; wet
The most important agent of chemical weathering is ______.
water
The disintegration and decomposition of rock at or near Earth's surface is called _______.
weathering
Breaking of rock or fragmentation is part of ______.
mechanical weathering
The downward movement of material as a viscous fluid is termed "slide". (T/F)
False. "Viscous" means thick, somewhat resistant to flow, but still moving.
Fabricated products do not break apart in response to natural processes. (T/F)
False. Concrete responds similarly to a conglomerate sedimentary rock when exposed to mechanical and chemical weathering processes.
the chemical alteration of rock is called combustion. (T/F)
False. Decomposition is the general term used for the chemical alteration or transformation of rock.
Quartz chemically weathers to produce abundant clay minerals. (T/F)
False. Feldspar minerals chemically weather to produce clays and other products including silica.
Mass wasting will most likely occur when materials are at an angle that is less than their angle of repose. (T/F)
False. If the angle is less than the angle of repose, the material will be stable.
Steep slopes should be used in landscaping to prevent erosion. (T/F)
False. In many circumstances, steep slopes enhance erosion.
All rocks weather at the same rate. (T/F)
False. Many rocks will weather at different rates based on composition and other factors.
In Bowen's Reaction Series, the minerals that form last are the most susceptible to chemical weathering. (T/F)
False. Olivine and pyroxene are less stable at the surface of Earth than quartz.
In general, the greater the slope, the thicker the soil. (T/F)
False. Soils on slopes are poorly developed because of the lack of soil moisture and plant growth, and increased erosion.
Lunar regolith is one of the 12 solid orders found in the soil taxonomy system. (T/F)
False. The soil orders end with "sols" after "solum" = soil, regolith is not really a soil.
The rate of weathering depends on atmospheric conditions. (T/F)
False. There are many factors that control the rate of weathering.
The key terms "weathering" and "erosion" are interchangeable. (T/F)
False. These processes are related to one another, often occur together, but they are not interchangeable; each has its own function and specific definition.
Weathering is the incorporation and transportation of rock materials. (T/F)
False. Weathering breaks the rock apart and into pieces so it is easier to move.
Weathering is a basic part of the hydrologic cycle. (T/F)
False. Weathering is a process that is most closely related to the rock cycle.
Mass wasting happens only as a result of gravity. (T/F)
There are other triggers that contribute to the process of mass wasting.
Mechanical weathering increases the surface area available to chemical weathering processes. (T/F)
True. A rock will weather faster if more surface area is exposed and if there is more than one process at work.
Important metals and elements can be concentrated into ore deposition through the process of weathering. (T/F)
True. Many important deposits of copper and silver deposits are also enriched through the weathering process.
Mass wasting is classified by the type of motion and the rate of movement. (T/F)
True. Mass movements can be sudden and deadly or slow, nearly imperceptible.
Exposure of rocks at Earth's surface to water and atmospheric conditions is most likely to cause ________.
chemical weathering
Whenever the characteristics and internal structures of minerals have been altered by weathering, they have undergone _______.
chemical weathering
The most influential control of soil formation is ______.
climate
The most widespread form of mass wasting is ______.
creep
In areas underlain by permafrost, solifluction is most likely to occur ____.
during the summer
The incorporation and transportation of rock material by mobile agents best describes ______.
erosion
The mechanical weathering process characterized by splitting off large slab-like sheets of rock often results in ______.
exfoliation domes
Material can move downslope by _____.
falling; sliding; flowing
The chemical weathering of ______ minerals produces clay minerals.
feldspar
After a series of freezing and thawing events, rock may be broken into pieces in a process called ____.
frost wedging
Soils often contain variations and vertical differences observed as general zones or layers called ______.
horizons
Mechanical weathering ______ the amount of surface area available for chemical weathering.
increases (as rocks are broken into smaller pieces).
Debris flows composed of volcanic material are called _____.
lahars
Which of the following materials is most likely to readily dissolve in a weakly acidic solution? basalt; quartzite; granite; marble; sandstone
marble
The process responsible for moving material downslope without the direct aid of running water, wind, or ice is _____.
mass wasting
