Summa 1

Question 1

occurs at or near Earth’s surface and are powered by energy from the sun

Answer 1

external processes

Question 2

It is a basic part of the rock cycle because they are responsible for transforming solid rock into sediment.

Answer 2

external processes

Question 3

the physical breakdown (disintegration) and chemical alteration (decomposition) of rocks to form soil or loose particles at or near Earth’s surface.

Answer 3

weathering

Question 4

physical breakdown

Answer 4

disintegration

Question 5

chemical alteration

Answer 5

decomposition

Question 6

_____ causes deterioration of building materials. It also weakens rocks, a great concern when weathered rocks are used for foundation.

Answer 6

Weathering

Question 7

types of weathering

Answer 7

mechanical(physical) and chemical

Question 8

accomplished by physical forces that break rock into smaller and smaller pieces without changing the rock’s mineral composition

Answer 8

Mechanical(Physical) Weathering

Question 9

involves breaking down rock components and internal structure and forming new compounds.

Answer 9

chemical weathering

Question 10

5 processes of physical weathering

Answer 10

unloading, frost wedging, salt crystal growth, thermal expansion and contraction, biological activity

Question 11

Upon removal of overburden (unloading), the elastic component of rock deformation is recovered and the rock expands, e.g. the overlying rocks are eroded or rocks are removed from a quarry

Answer 11

unloading

Question 12

The expansion caused by unloading may be sufficient to fracture the rock. Such naturally formed cracks are called,

Answer 12

joints

Question 13

The unloading of large plutons may split into sheets that are parallel to the mountain face, a process called

Answer 13

exfoliation/sheeting

Question 14

It is also known as ______ if the expansion occurs in granite to form rock slabs.

Answer 14

sheeting

Question 15

Liquid water expands by __% in volume when freezing.

Answer 15

9

Question 16

Liquid water expands by 9% in volume when freezing. So one of the most effective mechanical weathering processes is the wedging action of repeated cycles of freezing and thawing of water in rock fractures.

Answer 16

frost wedging/ice wedging

Question 17

Liquid water expands by 9% in volume when freezing. So one of the most effective mechanical weathering processes is the wedging action of repeated cycles of ______ ____ _____ of water in rock fractures.

Answer 17

freezing and thawing

Question 18

Conditions for ________ include moisture, rock fracture or weakness planes, and temperature fluctuation around the freezing point.

Answer 18

frost wedging

Question 19

Conditions for frost wedging include ____, _______, and ______ around the freezing point.

Answer 19

moisture, rock fracture or weakness planes, temperature fluctuation

Question 20

A product of frost wedging is _______ made of angular rock pieces piling up at the base of steep cliffs.

Answer 20

talus slope

Question 21

It begins when sea spray from breaking waves or salty groundwater penetrates crevices and pore spaces in rock. As this water evaporates, salt crystals form. As these crystals grow larger, they weaken the rock by pushing apart the surrounding grains or enlarging tiny cracks.

Answer 21

salt crystal growth

Question 22

As temperature changes, not all parts of a rock or all its minerals expand or contract by the same amount. So when rocks are heated or cooled, the mineral grains are subjected to differential stresses.

Answer 22

thermal expansion and contraction

Question 23

Accomplished by the activities of organisms, including plants, burrowing animals, and humans. Plant roots in search of minerals and water grow into fractures, and as the roots grow, they wedge the rock apart. Burrowing animals further break down the rock by moving fresh material to the surface, where physical and chemical processes can more effectively attack it. Decaying organisms also produce acids, which contribute to chemical weathering.

Answer 23

biological activity

Question 24

Organisms such as lichen and algae often live on bare rock and extract minerals from the rock by ion-exchange mechanisms.

Answer 24

chemical weathering

Question 25

This bio-chemical weathering process leaches minerals from the rock causing it to weaken and breakdown.

Answer 25

chemical weathering

Question 26

The decaying of plant materials can also produce acidic compounds which dissolve the exposed rock.

Answer 26

chemical weathering

Question 27

The presence of organisms growing, expanding, or moving across the surface of the rock also exerts a small amount of abrasion and pressure that gradually cause the ________ of the rock as the organisms extract various minerals.

Answer 27

mechanical weathering

Question 28

The most common form of biological weathering is when plant roots penetrate into cracks and crevices of rocks and cause the rock to split or break into smaller particles through mechanical weathering.

Answer 28

plant roots

Question 29

Although, this process is gradual, it can be fairly effective at breaking apart rocks that may already have a pre-existing weaknesses such as fractures, faults, or joints.

Answer 29

plant roots

Question 30

Burrowing, tunneling, and acid-secreting organisms are another form of biological weathering that chemically or mechanically contribute to weathering

Answer 30

organism activity

Question 31

Some animals may burrow or tunnel into rocks or cracks in rocks and cause the rock to break down and disintegrate. Small animals, worms, termites, and other insects, often contribute to this form of biological weathering.

Answer 31

organism activity

Question 32

Some organisms, such as snails, barnacles, or limpets, attach themselves to rocks and secrete acid acids that chemically dissolve the rock surface.

Answer 32

organism activity ; chemical weathering

Question 33

When rock comes in contact with components of the surface and atmosphere (water, oxygen, carbon dioxide), __________ occur that alter and destroy minerals of the rock. Water is the most important agent of chemical weathering.

Answer 33

chemical reactions

Question 34

______ is the most important agent of chemical weathering.

Answer 34

water

Question 35

______ weathering occurs at the surfaces of rocks, thus, the greater the surface area, the more intense the weathering. Thus the breaking of rock into smaller pieces by ______ weathering greatly accelerates _____ weathering.

Answer 35

Chemical; mechanical; chemical

Question 36

Water is an excellent solvent, capable of dissolving many chemical compounds. This is the result of polar nature of water molecules: the oxygen end has a small negative charge, the hydrogen end has a small positive charge.

Answer 36

dissolution

Question 37

In addition, CO2 in the atmosphere and soils reacts with water to produce ________

Answer 37

carbonic acid

Question 38

H2O + CO2 ->

Answer 38

H2CO3 (carbonic acid)

Question 39

CaCO³ + H²CO³ ->

Answer 39

Ca² + CO² + H²O

Question 40

________ is the reaction of acidic solutions with silicates (the most common mineral group). For example, the weathering of K-feldspar of granite is as follows

Answer 40

hydrolysis

Question 41

2KAlSi3O8

Answer 41

K-feldspar

Question 42

2(H+ + HCO3-) + H2O

Answer 42

carbonic acid

Question 43

Al2Si2O5(OH)4

Answer 43

kaolinite

Question 44

2K+ + 2HCO3-

Answer 44

in solution

Question 45

4SiO2

Answer 45

silica

Question 46

A product of the chemical breakdown of K-feldspar is clay mineral, ______, which is very stable at the surface. Consequently, clay minerals make up high percentage of soils.

Answer 46

kaolinite

Question 47

when oxygen (dissolved in the water) combines with iron to form iron oxide

Answer 47

oxidation

Question 48

Iron-rich minerals is subject to ,

Answer 48

oxidation

Question 49

4Fe + 3O2 ->

Answer 49

2Fe2O3 (hematite)

Question 50

Some minerals are more susceptible to chemical weathering than others. For silicates, the order of weathering (Goldrich's mineral stability series) is the same as the order of crystallization (so called Bowen's reaction series).

Answer 50

rock characteristics

Question 51

_______ is perhaps the single most important factor influencing weathering.

Answer 51

Climate

Question 52

______ and _____ have strong influences on both mechanical weathering (e.g. frost wedging) and chemical weathering. Thus, chemical weathering is ineffective in polar regions or arid regions because of the lack of free water.

Answer 52

Temperature ; moisture

Question 53

Climate controls the type and extent of weathering because of the combined effects of _______.

Answer 53

precipitation, temperature and vegetation

Question 54

_______ is most pronounced in the _____, where these factors reach maximum: and weathering is minimum in deserts and polar region, where these factors are minimal.

Answer 54

Weathering ; tropics

Question 55

Weathering is most pronounced in the tropics, where these factors reach maximum: and weathering is minimum in ____ and _____, where these factors are _____.

Answer 55

deserts; polar region; minimal

Question 56

geological processes that is occurring or formed beneath the Earth's surface

Answer 56

endogenic processes

Question 57

______ is the gradual addition of new material. When the Earth first accreted, it probably wasn’t spherical.

Answer 57

Accretion

Question 58

Accretion is the gradual addition of new material. When the Earth first accreted, it probably wasn’t spherical. ____ was generated and retained.

Answer 58

HEAT

Question 59

sources of internal heat:

Answer 59

accretionary heat, radioactive decay, partial melting and origin og the magma

Question 60

_____ attracts planetesimals to the proto-earth

Answer 60

Gravity

Question 61

______ accelerate on their journey, gaining kinetic energy

Answer 61

Planetesimals

Question 62

𝐾𝐸=

Answer 62

1/2𝑚𝑣^2

Question 63

Planetesimals strike the proto-earth at ______

Answer 63

high speed

Question 64

Their kinetic energy is converted to ___________

Answer 64

thermal energy (heat)

Question 65

Soon after it formed, each planet was partially heated by countless _______ crashing into it. This was material left over from the formation of the solar system, and the kinetic energy of the impactors was transformed into _______ when they collided.

Answer 65

planetesimals ; thermal energy

Question 66

This explains why we find _____ from undifferentiated asteroids that have been thermally altered — the asteroid they came from was not large enough to completely ___ but impacts melted portions of the surface.

Answer 66

meteorites ; melt

Question 66

This explains why we find _______ from undifferentiated asteroids that have been thermally altered — the asteroid they came from was not large enough to completely melt but impacts melted portions of the surface.

Answer 66

meteorites;

Question 67

The natural disintegration of certain isotopes to form new nuclei

Answer 67

radioactive decay

Question 68

Time for nuclei to decay given by a “half-life”

Answer 68

radioactive decay

Question 69

_____ is an important source of the Earth’s internal heat

Answer 69

Radioactive decay

Question 70

___ is the ultimate source of the energy that drives geological activity on any planet

Answer 70

Heat

Question 71

The ____ heat of the Earth, fueled by ___, is the "______" that drives the geological activity of the planet

Answer 71

internal; radioactivity; engine

Question 72

___, for example, erupt because the ___heat inside the Earth melts rock and creates supplies of molten magma;

Answer 72

Volcanoes; heat

Question 73

the magma is less ____ than surrounding rock, so it tends to ___ to the surface.

Answer 73

dense; rise

Question 74

_____ are also caused by pressure associated with the movements of molten rock.

Answer 74

Earthquakes

Question 75

Without radioactivity, the Earth’s _____ would have cooled long ago

Answer 75

interior

Question 76

Without radioactivity, the Earth’s interior would have cooled long ago. Volcanoes would be extinct, and there would be no earthquakes. Earth would be geologically _____.

Answer 76

dead

Question 77

______ is one of the main sources of heat inside the Earth.

Answer 77

Radioactivity

Question 78

26Al ® 26Mg + Energy + … (t1/2 = 0.72 x 106 yrs) 129I ® 129Xe + Energy + … (t1/2 = 16 x 106 yrs)

Answer 78

short-lived isotopes

Question 79

40K ® 40Ar + Energy + … (t1/2 = 1270 x 106 yrs) 232Th (t1/2 = 1400 x 106 yrs) 235U (t1/2 = 704 x 106 yrs) 238U (t1/2 = 4470 x 106 yrs)

Answer 79

long-lived isotopes

Question 80

_____ is a measure of particles’ speed, so increased _____ results in a higher temperature.

Answer 80

Temperature ; motion

Question 81

Radioactive material is therefore an _____, and it _____ the interior of the planet in which it’s trapped.

Answer 81

energy source; heats

Question 82

Evidence from the study of earthquake waves has shown that Earth’s crust and mantle are composed primarily of ____, not molten, rock.

Answer 82

solid

Question 83

Recall that igneous rocks are composed of a mixture of _____. Since these minerals have different ______, igneous rocks tend to melt over a temperature range of at least ___°C.

Answer 83

minerals; melting points; 200

Question 84

As rock begins to melt, the minerals with the lowest melting temperatures are the first to melt. If melting continues, minerals with higher melting points begin to melt, and the composition of the melt steadily approaches the overall composition of the rock from which it was derived.

Answer 84

partial melting

Question 85

As rock begins to melt, the minerals with the _____ melting temperatures are the first to melt.

Answer 85

lowest

Question 86

Most often, however, melting is not complete. The incomplete melting of rocks is known as _______, a process that produces most magma.

Answer 86

partial melting

Question 87

Also, because the molten material is less dense that the remaining solids, when enough of the melt collects, it ______ toward Earth’s surface.

Answer 87

rises

Question 88

Although the rate of temperature change varies considerably from place to place, it averages about 25°C per kilometer in the upper crust. This increase in temperature with depth is known as the geothermal gradient.

Answer 88

generating magma from solid rock

Question 89

Although the rate of temperature change varies considerably from place to place, it averages about ___°C per kilometer in the upper crust. This increase in temperature with depth is known as the _________.

Answer 89

25; geothermal gradient

Question 90

When a typical geothermal gradient is compared to the melting point curve for the mantle rock peridotite, the temperature at which peridotite melts is higher than the geothermal gradient. Thus, under normal conditions, the mantle is solid. However, tectonic processes exist that trigger melting by reducing the melting point (temperature) of mantle rock.

Answer 90

generating magma from solid rock

Question 91

When a typical geothermal gradient is compared to the melting point curve for the mantle rock ______, the temperature at which peridotite melts is _____ than the geothermal gradient.

Answer 91

peridotite; higher

Question 92

Thus, under normal conditions, the mantle is _____. However, tectonic processes exist that trigger melting by reducing the ____ (temperature) of mantle rock.

Answer 92

solid; melting point

Question 93

Pressure which also increases with depth influences the melting temperatures of rocks.

Answer 93

decrease in melting / decompression melting

Question 94

_____ which also increases with depth influences the melting temperatures of rocks.

Answer 94

Pressure

Question 95

Melting, which is accompanied by an increase in ____, occurs at progressively higher temperatures with increased depth.

Answer 95

volume

Question 96

Melting, which is accompanied by an increase in volume, occurs at progressively higher temperatures with increased depth.

Answer 96

decrease in melting /decompression melting

Question 97

This is the result of the steady increase in confining pressure exerted by the weight of overlying rocks.

Answer 97

decrease in melting / decompression melting

Question 98

Conversely, reducing confining pressure ____ a rock’s melting temperature. When confining pressure drops sufficiently, _______ is triggered.

Answer 98

lowers ; decompression melting

Question 99

Water causes rock to melt at lower temperatures.

Answer 99

addition of water

Question 100

_____ causes rock to melt at lower temperatures.

Answer 100

Water

Question 101

The introduction of ____ to generate magma occurs mainly at ______ plate boundaries where cool slabs of oceanic lithosphere descend into the mantle

Answer 101

water ; convergent

Question 102

At a depth of about ____ km (___ miles), the addition of water lowers the melting temperature of mantle rock sufficiently to trigger _____.

Answer 102

100; 60; partial melting

Question 103

Partial melting of the mantle rock peridotite generates hot basaltic magmas with temperatures that may exceed _____°C (____°F)

Answer 103

1250; 2300

Question 104

When enough mantle-derived basaltic magma forms, it buoyantly ___ toward the surface

Answer 104

rises

Question 105

When enough mantle-derived basaltic magma forms, it buoyantly rises toward the surface

Answer 105

Temperature increase(melting crustal rocks)

Question 106

The hot basaltic magma may ____ the overlying crustal rocks sufficiently to generate a ____, silica-rich magma.

Answer 106

heat; secondary

Question 107

If these low-density silica-rich magmas reach the surface, they tend to produce _________ that we associate with convergent plate boundaries.

Answer 107

explosive eruptions

Question 108

transfer of energy / thermal energy

Answer 108

heat

Question 109

exogenic

Answer 109

external

Question 110

asteroids has its own _____

Answer 110

gravity

Question 111

____ is important in keeping earth geologically alive

Answer 111

heat

Question 112

atoms of the same element that have the same amount of of protons but different number of neutrons

Answer 112

isotopes

Question 113

this results in different atomic mass

Answer 113

isotopes

Question 114

To have significant internal heat, a planet must be large enough to have sufficient radioactive material, and large enough to provide some insulation to retain that heat. So small asteroids, for example, don't have enough _____ to be _____ active. However, there is also an energy source that has affected all planets, regardless of their size.

Answer 114

internal heat; geologically