Chapter 6 Geology 1403

The ____-horizon is very similar to the parent material.

C

________ weathering is when there is a chemical transformation of rock into other compounds.

Chemical

How can an angular mass of rock become a spherical boulder?

Water enters joints in the rock, where it preferentially weathers the corners and edges of the rock into a roughly spherical shape.

Why does water frozen in the cracks of a rock help to break down the rock?

Water expands when frozen and physically forces the rock apart.

A vertical succession of soil horizons is called a soil profile.

A vertical succession of soil horizons is called a soil profile.

How does climate influence the weathering of rock?

Areas with high temperatures and abundant moisture will generally have the highest rates of chemical weathering.

Which horizons make up the topsoil?

O and A horizons

Which of the three images in Figure 2 would be most susceptible to chemical weathering and why?

Physical weathering has created more surface area for chemical weathering to attack.

How might the direction that a slope is facing influence soil formation?

The direction the slope faces determines how much solar radiation that its soil will receive, which determines the soil's temperature and moisture content.

Which of the following would decrease soil erosion? CHOOSE ALL THAT APPLY.

Vegetation planted parallel to the slope-Adding terraces to a slope

Which climate contains the optimum environment for chemical weathering?

Warm and wet

How does physical weathering cause chemical weathering to be more effective?

When a rock is physically broken into smaller pieces, there is more surface area on which chemical weathering can occur.

Which of the following is an example of chemical weathering?

a car fender getting rusty

frost wedging

expansion of ice forces a rock apart

________ is decayed remains of plant and animal life.

humus

E horizon

light-colored, depleted of soluble materials, little organic material.

What is salt weathering?

the formation of minerals in rock cracks during the evaporation of salty water, forcing rock apart

Of the responses provided, which is the predominant source of energy for most external processes that operate on Earth?

the sun

B horizon

− accumulation of clay particles from upper layers.

Biological activity

− living materials break down a rock.

Rainwater will combine with which atmospheric gas in order to create carbonic acid?

Carbon dioxide

Which acid is commonly responsible for the dissolution of limestone?

Carbonic

________ weathering occurs when differences in resistance or environmental factors produce uneven surfaces on rocks.

Differential

Which of the following statements about soil formation is accurate?

Dissimilar soils can develop from the same parent material.

Earth's surface is subjected to unusually high rates of weathering. The Moon and some of the inner planets of our solar system are also subject to surface weathering, but at much slower rates. Which of the following statements most reasonably explains Earth's uniquely rapid weathering rates?

Earth has running water at the surface.

Study this image and think about what the climate is like in this region. Which weathering process would you assume is responsible for material A?

Frost wedging

Sand dunes are typically dominated by quartz grains and very little other mineral matter. Why does this selection occur?

Quartz is extremely resistant to all forms of chemical weathering.

Which type of weathering produces an exfoliation dome?

Sheeting

Which of the following rocks will be most resistant to weathering?

Solid bedrock

Why are soils in tropical rain forests not well suited for farming?

Soluble materials such as calcium carbonate are severely leached from the soil.

In the above picture, why have the headstone on the right and the headstone on the left weathered differently?

The headstone on the left is made of granite, which is composed mostly of quartz and feldspar, whereas the headstone on the right is made of marble, which is composed of calcite.

Which soil order is characteristic of dry, desert regions?

aridosol

The chemical weathering process known as dissolution is most effective in the breakdown of which of the following minerals?

calcite

Of the five basic controls of soil formation, which factor is the most influential in soil formation?

climate

________ is considered the most influential control of soil formation

climate

O horizon

consists largely of organic material, still identifiable in uppermost layer.

Which type of chemical weathering is very efficient at weathering limestone?

dissolution

Considering the following list, which is not an example of chemical weathering?

exfoliation

Mature soils are characteristic of steep slopes.

false

During hydrolysis, ________ commonly decompose into clay minerals, silica, and soluble constituents.

feldspars

During hydrolysis, ions and clay minerals are produced by the decomposition of which of the following Earth materials?

feldspars

Rank the rocks from fastest weathering to slowest weathering.

forest/grassland soil, wetland soil, desert soil

rank the rocks from fastest weathering to slowest weathering

peridotite, gabbro, diorite, granite

________ are the primary source of organic matter in soils.

plants

Hydrolysis

positive ions are replaced with H + or O H −.

Oxidation

positive ions lose electrons to oxygen.

The chemical weathering process known as oxidation would be most effective in the breakdown of which of the following Earth materials?

pyroxenes

Sheeting

reduction of pressure on a pluton results in concentric layers breaking off.

Using the picture of the Entrada Sandstone in Figure 1, try to identify the evidence of physical and/or chemical weathering present.

rusty color and fracturing

Using the soil texture diagram above, identify the soil that consists of 60 percent sand, 30 percent silt, and 10 percent clay.

sandy loam

All modification of Earth's outer surface is initiated by which of the following processes?

wheathering

Why is soil a nonrenewable resource?

Because it forms very slowly

Which weathering process is illustrated in the photo above?

Biological activity

Soil develops in response to interactions between which Earth spheres?

Biosphere, atmosphere, geosphere, and hydrosphere

What do freeze-thaw and salt weathering have in common?

Both freeze-thaw and salt weathering require rain and force rocks apart physically.

A horizon

composed of a mixture of humus and mineral material.

Which of the following is true of lunar soil when compared with terrestrial soil?

It does not contain organic matter.It cannot support life. It does not contain air.

________ weathering is when physical forces break solid rock into smaller sediments.

Mechanical

What is the definition of physical weathering?

Mechanical processes break substances into smaller pieces.

How do the products of the two categories of weathering differ from each other?

Mechanical weathering results in broken pieces that are of the same composition as the original material, whereas chemical weathering alters the composition of the material.

Which of the following is a good method to reduce soil erosion as a result of strong winds?

Planting rows of trees and shrubs

What is an everyday example of mechanical weathering? CHOOSE ALL THAT APPLY.

Potholes forming in the street Tree roots cracking a sidewalk

Which type of rock is most likely to form a ridge due to differential weathering?

granite

Once weathering begins and particles are produced, which factor is most influential in moving them around Earth's surface?

gravity

Which of the following is not an agent of erosion?

heat

Salt crystal growth

mineral crystal development forces a rock apart.

Which of the following components makes up the largest percentage of most soils?

mineral portion

Dissolution

minerals dissolved in acidic water.

Of the following processes, which is not an example of mechanical weathering?

oxidation

C horizon

partially altered parent material that is easily identifiable.

________ is the upper few feet of regolith that contains minerals and organic matter, water, and air and is capable of sustaining life.

soil

When a rock is mechanically weathered,

the surface area of the rock is increased, which allows a greater amount of chemical weathering to occur.

The longer a soil has been forming, the ________ it becomes and the ________ it resembles the parent material.

thicker; less

Chemical weathering will break down a rock by changing the molecular compounds that make up the rock.

true

Fine-grained particles or iron oxide accounts for red, yellow, and brown colors in soil horizons.

true

Water expands when it freezes.

true

Of the following, which is not an example of Earth's external processes and/or external process-driven phenomena?

volcanoes

What is the most important agent of chemical weathering?

water