Geology 101 Midterm #2 - Skinner

Front 1

Compared to low-grade metamorphic rocks, high-grade rocks _____.

Back 1

are produced at greater temperatures and pressures

Front 2

Two common metamorphic rocks that typically lack foliation are _____

Back 2

quartzite and marble

Front 3

A buried body of shale is subjected to differential stress, causing clay minerals to realign and producing slate. This is an example of _____

Back 3

Metamorphism

Front 4

The process of high-grade metamorphic rocks being altered to form low-grade metamorphic rocks is termed _____ metamorphism

Back 4

Retrograde

Front 5

Thermal (contact) metamorphism _____.

Back 5

Occurs in areas surrounding igneous intrusions

Front 6

Metamorphism may be induced by _____.

Back 6

1) contact with a hot pluton
2) contact with hot groundwater
3) heat and pressure associated with deep burial

Front 7

How many seismic stations are necessary to find the epicenter of an earthquake?

Back 7

3

Front 8

If, during an earthquake, a hanging wall slides upward relative to a footwall, the fault is termed _____ if the fault is steep (closer to vertical than horizontal)

Back 8

Reverse

Front 9

Seismic gaps are important in earthquake prediction because they mark zones___________.

Back 9

along plate margins where stress is building to the level necessary for an earthquake

Front 10

The Earth's mantle is believed to be solid, not liquid, because

Back 10

S waves travel through the mantle but not through liquid.

Front 11

The epicenter of an earthquake is

Back 11

A point directly above the focus

Front 12

Which characteristics best describe S waves?

Back 12

Second to arrive, move through the Earth's mantle, will not move through a liquid

Front 13

Where is Mt Everest located?

Back 13

Asia

Front 14

Orogeny

Back 14

An episode of mountain buiding

Front 15

A body of rock affected by tensile stress will likely undergo _____.

Back 15

stretching

Front 16

Dip and strike measurements are used to describe the orientation of:

Back 16

1) bedding planes.
2) joints.
3) faults.
4) planar surfaces in metamorphic rocks.

Front 17

Which eon of geologic time is represented by rocks containing abundant shelly fossils?

Back 17

Phanerozoic

Front 18

Why is radiocarbon dating only rarely applied in geological work?

Back 18

The half-life of carbon-14 is so short that it can be used only to date materials that are less than 70,000 years old.

Front 19

Uniformitarianism is succinctly summarized by which phrase?

Back 19

The present is the key to the past

Front 20

Dinosaurs first appeared during the _____ period.

Back 20

Triassic

Front 21

The Cambrian period is a time in Earth history when _____.

Back 21

the first abundant shelly organisms appear in the fossil record

Front 22

Period names on the geologic time scale, such as Devonian and Permian, provide examples of _____.

Back 22

Relative age

Front 23

The Earth is approximately how old?

Back 23

4.6 billion years old

Front 24

Which gas found in today's atmosphere was absent in the Hadean's and Archean's?

Back 24

Oxygen

Front 25

Convergence along the western margin of North America during the Cenozoic gave way to rifting forces that created the characteristic topography of the _____.

Back 25

Basin and range province

Front 26

Oil drilling not only provides gasoline and electric power but also material incorporated in _____.

Back 26

Plastics

Front 27

How does petroleum form?

Back 27

by the decomposition of organic material in sedimentary rock

Front 28

The most important energy source currently in use:

Back 28

Fossil fuel

Front 29

The conditions necessary for the accumulation of oil in an economic deposit:

Back 29

1) reservoir beds
2) sufficient heat and pressure to convert organic matter to hydrocarbons
3) a trap of barrier to migration
source bed

Front 30

Where would you expect to see solifluction?

Back 30

Siberia

Front 31

Which of the following factors decreases the risk of mass movement?

Back 31

Adding vegetation to the side of a hill.

Front 32

Gneiss

Back 32

A foliated metamorphic rock with alternating layers of light and dark minerals

Front 33

Metamorphic transformations occur while a rock is in:

Back 33

the solid state

Front 34

Compared to low-grade metamorphic rocks, high-grade rocks _____.

Back 34

Are produced at greater temperatures and pressures

Front 35

Within a single mountain range, _____.

Back 35

it is possible to find a variety of metamorphic rocks produced in distinct facies, including high-, low-, and intermediate-grade rocks

Front 36

Precambrian metamorphic rocks are exposed at the surface _____.

Back 36

At places in continental interiors termed "shields."

Front 37

Dynamothermal metamorphism occurs when _____.

Back 37

rock becomes buried deeply during continental collision and mountain building

Front 38

Metamorphism

Back 38

changes in mineralogy and texture in response to heat and pressure

Front 39

How is strike measured?

Back 39

as the orientation of a horizontal line on a bedding plane

Front 40

Displacement along a strike-slip fault is best described as:

Back 40

horizontal displacement of rocks on either side of the fault

Front 41

What is the distinction between joints and faults?

Back 41

Faults are fractures along which displacement has occurred; displacement does not occur along joints

Front 42

Fault breccia

Back 42

Movement along faults that often produces sharply angled rock fragments

Front 43

Syncline

Back 43

A fold shaped like an elongate trough

Front 44

Shields

Back 44

Regions where Precambrian metamorphic rocks are exposed at the surface

Front 45

Fossil succession

Back 45

A valuable principle for relative dating that is based on the process of organic evolutio

Front 46

Unconformity

Back 46

a buried erosional surface

Front 47

Catastrophism

Back 47

The concept of sudden events that created deep canyons, raised mountains, created landmasses from the sea, and brought about other dramatic changes on the Earth

Front 48

Which technique is most useful in absolute dating of rock bodies?

Back 48

Radiometric dating

Front 49

James Hutton, the "father of geology," put forth the principle of _____

Back 49

Uniformitarianism

Front 50

What has the age of the Earth has been determined from?

Back 50

meteorites

Front 51

Most continental crust formed during which eon?

Back 51

Archean Eon

Front 52

The current composition of our atmosphere is in part due to _______

Back 52

Photosynthesis

Front 53

When did vascular plants first develop on land?

Back 53

Middle Paleozoic

Front 54

When did the Atlantic Ocean begin to form?

Back 54

During the Jurassic time period.

Front 55

When did the genus Homo appear on Earth?

Back 55

Pliocene (5.3 - 1.6 Ma)

Front 56

The convergent boundary that formed the Rocky Mountains was replaced with?

Back 56

A transform fault

Front 57

During the Pleistocene people migrated from continent to continent by?

Back 57

Walking on land bridges due to lower sea level

Front 58

Which mineral resources are considered renewable?

Back 58

No mineral resources are renewable.

Front 59

Which coal contains the most carbon per volume?

Back 59

Anthracite

Front 60

The high electrical conductivity associated with metallic bonds results from _____.

Back 60

The ability for outer electrons to move freely from atom to atom.

Front 61

Most of the hydrocarbons within oil and natural gas are derived from the breakdown of organic matter from once-living _____.

Back 61

Plankton

Front 62

An example of harnessing geothermal energy is

Back 62

Using geothermally heated ground water.

Front 63

Porphyry copper deposits like the one at Bingham, Utah, are commonly

Back 63

Associated with magmas at subduction zones

Front 64

Two major problems associated with the use of coal as a source of energy

Back 64

Acid rain and open-pit mines

Front 65

Problems with the use of nuclear fuels as an energy source include

Back 65

the disposal of spent but still radioactive fuel

Front 66

Which type of mass movement takes place most gradually?

Back 66

Creep

Front 67

The immediate cause of incidents of mass movement?

Back 67

Gravitation

Front 68

Which type of mass movement travels down a curved surface?

Back 68

Slump

Front 69

Strictly speaking, which of the following types of mass movement is a landslide?
2) mudflow
1) rock slide

Back 69

Rock slide

Front 70

Foliation

Back 70

Repetition of planar surfaces or layers

Front 71

Slate

Back 71

The finest-grained foliated metamorphic rock, forms by the metamorphism of shale under relatively pressures and temperatures. Has foliation and cleavage.

Front 72

Schist

Back 72

A medium to coarse-grained metamorphic rock that possesses a type of foliation, called schistosity, defined by large flakes. It forms at high temperatures

Front 73

Gneiss

Back 73

compositionally layered metamorphic rock, typically composed of alternating dark colored and light colored layers...has striped appearance.

Front 74

Metamorphic intensity

Back 74

Defines the type of rock. Low grade = shale and sandstone, high grade = gneiss

Front 75

Important non foliated metamorphic rocks:

Back 75

Quartzite and marble

Front 76

Quartzite

Back 76

Protolith = quartz sandstone

Front 77

Marble

Back 77

Protolith = limestone

Front 78

Causes for earthquakes:

Back 78

sudden formation of new fault
sudden slip on an existing fault
sudden change in the arrangement of atoms in rock minerals
movement of magma in a volcano
explosion of volcano
giant landslides
meteorite impact
underground nuclear-bomb tests

Front 79

focus

Back 79

Location where a fault slips during an earthquake (hypocenter)

Front 80

Epicenter

Back 80

The point on the surface of the Earth directly above the focus of an earthquake

Front 81

P-waves

Back 81

compressional seismic waves that move through the body of the Earth

Front 82

S-waves

Back 82

Seismic shear waves that pass through the body of the Earth.

Front 83

Liquefaction

Back 83

the abrupt loss of strength of a wet sediment in response to ground shaking

Front 84

Strain

Back 84

the change in shape that deformation causes

Front 85

Brittle deformation

Back 85

breaking, shattering, cracking, and fracturing

Front 86

Ductile deformation

Back 86

objects that change shape without visibly breaking

Front 87

Types of stress

Back 87

Compression - when rock is squeezed
Tension - when rock is pulled apart
Shear - when one side of a rock body moves sideways past the other side

Front 88

Types of faults

Back 88

strike-slip - one block slides past another horizontally
thrust/reverse faults - hanging-wall block moves up the slope of the fault
Normal faults - hanging wall block moves down the slope of the fault
Types of strike-slip: left- and right-lateral
oblique-slip - sliding occurs diagonally on the fault plane
Dip-slip - sliding occurs up or down the slope of the fault

Front 89

Types of folds

Back 89

anticline - n-shaped
syncline - u-shaped
Dome/basin

Front 90

Isostasy

Back 90

The condition that exists when the buoyancy force pushing lithosphere up equals the gravitational force pulling lithosphere down.

Front 91

James Hutton

Back 91

"Father of geology." Idealized principle of uniformitarianism

Front 92

Uniformitarianism

Back 92

physical processes we observe today also operated in the past and were responsible for the formation of the geologic features we see in outcrops.

Front 93

unconformity

Back 93

a period of nondeposition and possibly erosion

Front 94

Types of unconformities

Back 94

angular unconformity - rocks are tilted by folding or faulting before being exposed
nonconformity - sedimentary rocks overlie intrusive igneous/metamorphic rocks, then the rocks cool and are uplifted.
Disconformity - when beds of sediment are parallel, contact area between them = interruption in deposition.

Front 95

Relative vs. Absolute Age

Back 95

Relative = age of a feature with respect to another
Absolute/numerical = age of a feature given in years

Front 96

William Smith

Back 96

Fossil succession - extinction is forever -- once a fossil species disappears at a horizon in a sequence of strata, it never reappears higher in the sequence.

Front 97

The four eons

Back 97

Hadeon, Archean, Proterozoic, and Phanerozoic

Front 98

Hadean Eon

Back 98

Formation of the Earth, very hot early stages. Ended when intense meteorite bombardment of Earth ceased.

Front 99

Archean Eon

Back 99

Most of the continental crust formed (80%)
Early life - chemical fossils, isotope signatures, and fossil forms

Front 100

Proterozoic Eon

Back 100

Means "first life"
Encompasses 1/2 of Earth's history
Supercontinent = Rodina
Oxygen-rich environment
Glaciers formed

Front 101

Phanerozoic Eon

Back 101

Means "visible life."
Life diversifies
Three eras: paleozoic, mesozoic, and cenozoic

Front 102

Paleozoic Era

Back 102

Life evolution/Cambrian explosion of life
Green-house conditions - sea level rose and continents flooded
Ice-house conditions - seas retreated
Pangaea Formed

Front 103

Cambrian explosion of life

Back 103

In cambrian period (Paleozoic Era) when life underwent remarkable diversification

Front 104

Mesozoic Era

Back 104

Triassic and Jurassic Periods
Pangaea started to break up
Dinosaurs appeared during the end of the Triassic period
Cretaceous Period - Earth heated up, modern fish appeared and became dominant, ended with 10 km meteorite that hit Mexico (K-T boundary catastrophe)

Front 105

Cenozoic Era: the final stretch to the present

Back 105

Global climate rapidly shifted to icehouse conditions - led to Pleistocene ice age
This is when our ancestors appeared

Front 106

The Evolution of Earth

Back 106

Hadean Eon
Archean Eon (Precambrian)
Proterozoic Eon (Precambrian)
Phanerozoic Eon: Paleozoic(cambrian, ordovician, silurian, devonian, and Carboniferous periods), Mesozoic (Triassic, Jurassic, and Cretaceous periods), and Cenozoic Eras

Front 107

Oil Window

Back 107

The narrow range of temperatures under which oil can form in a source rock.
Topmost 6-9 km of crust
<90 and >160 = oil and natural gas, 160<remaining oil breaks down to form natural gas,

Front 108

Oil Reservoirs

Back 108

The known supply of oil held underground

Front 109

Alternates to fossil fuel and positives/negatives

Back 109

Wind power: clean and renewable but expensive
tidal power: only available where there's a tidal range of at least 8 m
solar power: sun doesn't always shine and it's expensive!!
hydroelectric power: dams silt up, stops sediment transport, and messes up river ecology

Front 110

How are ores deposited?

Back 110

Magma - ores settle in the bottom of magma chambers
Sedimentary deposits
Leech deposits

Front 111

Difference between quarries and mines:

Back 111

Stone comes from quarries, ore comes from mines

Front 112

How coal forms:

Back 112

Coal is decomposed land plants in swamps near coasts, and on floodplains that become more and more carbonized by bacteria, heat, and pressure that remove other elements.

Front 113

Creep

Back 113

Extremely slow movement of soil and regolith – 1 to 10 mm/year
a. Heaving of soil – expansion and contraction is the primary cause
i. Wet-dry cycles
ii. Freeze-thaw cycles

Front 114

Flow

Back 114

Mixtures of water, mud and rock
Liquified soil flows downhill
Water lubricates mass of soil and rock
Large boulders, building etc. may be carried by viscous fluid

Front 115

Slides

Back 115

Mass movements along well defined slippage planes

Front 116

Causes of mass movement

Back 116

Gravity
Fractures and dirt
Slope stability
Fire removes vegetation
Earthquakes
Lahars

Front 117

What's important about the beginning of the Paleozoic Era?

Back 117

That's when diversification of life took off

Front 118

When is the age of fish?

Back 118

Devonian Period

Front 119

What's included in the Carboniferous Period

Back 119

Mississippian and Pennsylvanian (in that order)

Front 120

Body waves

Back 120

Seismic waves that pass through the interior of the Earth