Deck 5: Weathering and Soil

Question 1

Without chemical weathering, the elevated levels of carbon dioxide in the atmosphere would have long ago made the Earth too hot to sustain life.

Answer 1

True

Question 2

Clay minerals help hold water and clay nutrients in soil.

Answer 2

True

Question 3

Sand-size grains of feldspar can be preserved in a soil profile over great time periods because of feldspar's resistance to chemical weathering.

Answer 3

False

Question 4

The B-horizon in soil is the zone of accumulation.

Question 5

Hydrogen ions given off by natural acids can disrupt the crystal structure of most minerals, making the structure susceptible to further decomposition.

Question 6

All rocks chemically weather the same way.

Question 7

The only processes that affect rock are weathering and climate.

Question 8

Because the crystal structure of ice is different from that of water, liquid water expands when it freezes.

Question 9

Plants, such as roots growing in cracks, and animals compacting the soil, have little influence on mechanical weathering.

Question 10

Transportation is the picking up or physical removal of rock particles by an agent such as running water or glaciers.

Question 11

When feldspar is attacked by carbonic acid it forms clay minerals.

Question 12

The reduction of pressure on a body of rock can cause it to crack as it expands.

Question 13

Expanding ice in soil pushes large boulders down into the ground.

Question 14

Chemical weathering will eventually change a quartz crystal into clay minerals.

Question 15

The single most important agent for the chemical weathering is temperature.

Question 16

Ordinary rain has a pH of about 5.5 to 6 from the carbon dioxide in the atmosphere and from natural sources of acidic sulfur gases.

Question 17

The term mechanical weathering refers to changes in a rock that are physical; there is little or no chemical change.

Question 18

Because of the slow pace of weathering processes, it takes millions of years for a viable soil profile capable of supporting plant life to develop in most areas.

Question 19

An acid is a chemical compound that gives off hydrogen ions (H⁺) to a chemical reaction.

Question 20

Oxygen is abundant in the atmosphere but it does not combine with minerals of the Earth's crust.

Question 21

The most important natural source for the formation of acid for rock weathering at the Earth's surface is dissolved _______.

A) carbon dioxide
B) hydrothermal effluent
C) seawater
D) mantle plumes
E) comets

Question 22

________ forms as a chemical weathering product of iron-rich minerals.

A) Hematite
B) Limonite
C) Quartz
D) Both hematite and limonite are correct.
E) All of the choices are correct.

Question 23

The removal of a great weight of rock above a batholith by erosion allows the granite to expand forming ______.

A) sheet dikes
B) weathering rinds
C) sheet joints
D) cooling fractures
E) thermal cracks

Question 24

When fossil fuels are burned _____, enter the atmosphere to form acid rain.

A) oxides of nitrogen (NO₂) and sulfur (SO₂)
B) hydrochloric acids
C) oxalic acids
D) hydrogen and bicarbonate ions
E) helium and argon

Question 25

____ tend(s) to weather much faster than sandstone.

A) Shale
B) Granite
C) Chert
D) Gneiss
E) Most other rock types

Question 26

Ferromagnesian minerals such as pyroxene, amphibole, biotite, and olivine are chemically altered in the presence of _____.

A) quartz
B) helium
C) oxygen
D) argon
E) mica

Question 27

_______ are commonly left after complete chemical weathering.

A) Olivine and calcium plagioclase
B) Orthoclase feldspars
C) Halite and gypsum
D) Calcite and dolomite
E) Quartz and clay minerals

Question 28

Sulfuric acid is produced naturally during __.

A) emission of soil gas
B) carbonate mineral decomposition
C) normal life functions of plants and animals
D) some volcanic eruptions
E) the weathering process

Question 29

___ is the picking up and physical removal of rock particles by an agent such as wind, flowing liquid water, or glaciers.

A) Weathering
B) Extraction
C) Erosion
D) Deposition
E) Provenance

Question 30

_____ is the mineral least susceptible to chemical attack on the Earth's surface.

A) Olivine
B) Calcite
C) Halite
D) Quartz
E) Feldspar

Question 31

Water that has trickled down into a joint in a rock can freeze, expand, and _____.

A) glue the rock more tightly together
B) make the rock harder
C) seal the crack thereby preventing further weathering
D) widen the crack and hastening the rock's disintegration
E) displace surface acids that may weaken the rock

Question 32

_______ refers to the group of destructive processes that change the physical and chemical character of rocks at the Earth's surface.

A) Weathering
B) Extraction
C) Erosion
D) Deposition
E) Provenance

Question 33

The ____ describes the process in which this dominant greenhouse gas circulates among Earth systems.

A) calcium cycle
B) sodium cycle
C) potassium cycle
D) helium cycle
E) carbon cycle

Question 34

Water can combine with iron oxide to form ______.

A) silica
B) limonite
C) calcium, sodium, or potassium ions
D) galena
E) hydrogen ions

Question 35

Chemical weathering generally proceeds __.

A) at about the same rate throughout a rock body
B) fastest in the intact interior of a rock body, where ions easily move short distances from grain to grain
C) fastest on flat joint (crack) faces that are distant from any corners or edges
D) along contacts between mineral grains
E) fastest at the tip of growing cracks deep within the rock

Question 36

Frost wedging is most effective __.

A) in areas with many days of freezing and thawing
B) in the winter when the rock is frozen solid for months on end
C) in the spring and fall in very dry desert areas where temperatures dip down below 0 $\degree$ C at night and above 0 $\degree$ C during the day
D) in the summer when abundant rainfall percolates through the cracks to freeze in contact with the very cold rock found deep below the surface

Question 37

______, formed as water evaporates inside small spaces in rock, helps disintegrate desert rocks.

A) Calcite
B) Salt
C) Quartz
D) Hematite
E) Ice

Question 38

When feldspar is attacked by carbonic acid it forms _____.

A) water, clay, and potassium
B) a clay mineral
C) clays and halite
D) potassium, calcium, and bicarbonate ions
E) potassium feldspar, which does not undergo chemical weathering

Question 39

What, in terms of Earth systems, forms an essential interface between the geosphere, biosphere, hydrosphere, and atmosphere?

A) chert
B) quartz
C) soil
D) oxides of iron and aluminum
E) ferromagnesian minerals

Question 40

_______ is a byproduct of rock weathering.

A) Soil
B) Metamorphic rock
C) Igneous rock
D) Water
E) Oil

Question 41

______ is wind transported and deposited sediment.

A) Laterite
B) Lahar
C) Loam
D) Loess
E) Gelisol

Question 42

___ are the most common materials precipitated as cement, which binds loose particles of sand into a solid sedimentary rock.

A) Calcite and fluorite
B) Silica and hematite
C) Clay and silica
D) Calcite and silica
E) Feldspar and calcite

Question 43

At the surface of the Earth, ultramafic rocks in kimberlite pipes weather away leaving behind concentrations of _____.

A) diamonds
B) pearls
C) emeralds
D) olivine
E) topaz

Question 44

The _____ horizon is the incompletely weathered parent material lying below the B-horizon.

A) A
B) B
C) C
D) E
E) O

Question 45

The _______ horizon is the dark-colored soil horizon that is rich in organic material and forms just below the surface vegetation.

A) A
B) B
C) C
D) E
E) O

Question 46

Which of the following landforms are created from unloading?

A) volcanoes
B) pressure release domes
C) sink holes
D) exfoliation domes
E) regolith

Question 47

______ is weathered unconsolidated material on top of solid bedrock.

A) Clay
B) Sand
C) Mud
D) Dirt
E) Regolith

Question 48

The process of chemical weathering is also called ____.

A) chemical decomposition
B) rock decomposition
C) dissolution
D) decomposition
E) weathering decomposition

Question 49

Compared with quartz, minerals that include the positively charged ions of aluminum, iron, magnesium, and calcium are ___ vulnerable to chemical weathering by acidic solutions.

A) just as
B) less
C) more
D) not

Question 50

Under wet and humid tropical conditions the least soluble material is the aluminum oxide called _____.

A) limonite
B) chert
C) bauxite
D) peat
E) humus

Question 51

Of the many processes that cause rocks to disintegrate, the most effective are ____.

A) animal burrowing and frost wedging
B) pressure release and frost action
C) weathering and erosion
D) transportation and deposition
E) all listed are effective

Question 52

A ___ soil is one that develops from the bedrock directly beneath it.

A) residual
B) residential
C) regolith
D) retransported
E) retrograde

Question 53

Plants and burrowing organisms contribute to soil development by __.

A) establishing small holes and pathways for water and nutrients to flow
B) contributing carbon dioxide and organic acids
C) contributing their waste products, which act as nutrients
D) breaking up solid particles and churning the soil profile
E) All of the answers are correct.

Question 54

In tropical regions where temperatures are high and rainfall abundant, highly leached soils called _______ (oxisols) form.

A) laterite soil
B) lateral soil
C) transported soil
D) paleosol
E) pelagic soil

Question 55

In arid climates, soils are thin and soil water tends to move ______

A) laterally
B) downward
C) upward
D) only within a given soil horizon
E) sluggishly, if at all

Question 56

The _______ horizon is the uppermost layer of a soil; it consists of organic material.

A) A
B) B
C) C
D) E
E) O

Question 57

As soils mature, distinct layers called ______ appear.

A) strata
B) units
C) beds
D) layers
E) horizons

Question 58

The solution of calcite in a limestone supplies substantial amounts of ______ to ground water.

A) calcium ions in solution
B) an acid
C) bicarbonate ions in solution
D) All of the choices are correct.
E) Both calcium ions in solution and bicarbonate ions in solution.

Question 59

A soil formed entirely through the weathering of basalt would not contain sand-sized grains of __.

A) clay
B) feldspar
C) olivine
D) pyroxene
E) quartz

Question 60

Olivine weathers rapidly because its isolated silicon-oxygen tetrahedra are held together by _________ ionic bonds to iron and magnesium.

A) strong
B) long
C) weak
D) acid resistant
E) short