Geology 104 Exam 2

Front 1

Define "differential stress"

Back 1

Stress is not equal in all directions

Front 2

What is "confining stress"?

Back 2

Also called "lithostatic stress", confining stress is uniform stress that operates equally in all directions.

Front 3

What metamorphic facies occurs above subduction zones with temperatures 300-550°C, and 3-10 kb of pressure?

Back 3

Greenschist facies occur above subduction zones under relatively low temperatures and pressures.

Front 4

What metamorphic facies occurs above subduction zones with temperatures 550-750°C and 4-11 kb of pressure?

Back 4

Amphibolite facies occur above subduction zones under intermediate pressures and temperatures.

Front 5

What metamorphic facies occurs above subduction zones with temperatures >700°C and 4-11 kb of pressure?

Back 5

Granulite facies occur above subduction zones under very high pressures and temperatures.

Front 6

What metamorphic facies occurs in subduction zones with temperatures 50-400°C and under 4-11 kb of pressure?

Back 6

Blueschist facies occur in subduction zones under low temperature, high pressure conditions.

Front 7

Define "hornfels"

Back 7

Hornfels are fine-grained, non-folated rocks formed from intruding shale.

Front 8

Define "protolith"

Back 8

A protolith refers to a "parent rock"

Front 9

What is slate's protolith?

Back 9

Shale is slate's parent rock.

Front 10

What is marble's protolith?

Back 10

Limestone is marble's parent rock.

Front 11

What are two major sources of radon in central Wisconsin?

Back 11

Granite and glacial till are two major sources of radon in central Wisconsin.

Front 12

What element and process produces radon?

Back 12

Radon is produced by the radioactive decay of radium-226. It is a product of the decay chain of the uranium series.

Front 13

What are the health impacts of radon?

Back 13

Radon exposure has been linked to lung cancer.

Front 14

What rock is the source of the high radon concentrations in north-central Wisconsin?

Back 14

Soil derived from granite and carbonate rock is the principal geological factor leading to elevated indoor radon in Wisconsin.

Front 15

Why are glacial deposits also a source of radon?

Back 15

The sandy tills derived from granitic rock have moderate to high uranium content.

Front 16

How can high radon concentrations be remediated in homes?

Back 16

Sealing and caulking openings in the concrete foundation can prevent radon from entering the home.

Front 17

Name six stratigraphic laws:

Back 17

1. Original horizontality

2. Original lateral continuity

3. Superposition

4. Cross-cutting relationships

5. Inclusions

6. Faunal succession

Front 18

Define "original horizontality"

Back 18

Original horizontality refers to the law that sediments are originally deposited in horizontal beds or layers.

Front 19

Define "original lateral continuity"

Back 19

Original lateral continuity refers to the law that sedimentary beds are originally deposited over a large geographic area such that the sedimentary layers are laterally continuous in all directions.

Front 20

Define "superposition" as it relates to stratigraphy.

Back 20

Superposition refers to the law that sedimentary beds are deposited sequentially such that the oldest layers are on the bottom and layers become progressively younger towards the top of a stratigraphic sequence.

Front 21

Define "cross-cutting relationship"

Back 21

Cross-cutting relationship refers to the law that older rocks may be crosscut by younger rocks. Therefore, faults, dikes, or other cross-cutting features are younger than the layers that are truncated.

Front 22

Define "inclusions" as it relates to stratigraphy

Back 22

Inclusions refers to the law that fragments of preexisting rocks (called inclusions) are older than the rocks which contain these fragments.

Front 23

Define "faunal succession"

Back 23

Faunal succession refers to the law that distinctly different fossil groups succeed other fossil groups through time such that the fossil assemblages may demonstrate age changes in fossiliferous rocks.

Front 24

Name an isotope used to identify Precambrian age rocks

Back 24

Uranium-238 (lead-206)

Front 25

Name a specific rock enriched in uranium-238

Back 25

Uranium-238 is found in granite, specifically the zircon mineral.

Front 26

Define "strike" as it relates to faults

Back 26

Fault strike is the direction of a line created by the intersection of a fault plane and a horizontal surface.

Front 27

Define "dip" as it relates to faults

Back 27

Fault dip is the angle between the fault and a horizontal plane.

Front 28

What is a "strike-slip fault"

Back 28

In a strike-slip fault, rocks move horizontally with little or no vertical movement.

Front 29

What is a "dip-slip fault"?

Back 29

Dip-slip faults are inclined fractures where the blocks have mostly shifted vertically.

Front 30

Which direction does the hanging wall move on a normal fault? What force is responsible?

Back 30

On a normal fault, the hanging wall moves down as a result of tension.

Front 31

Which way does a hanging wall move on a reverse fault? What force is responsible?

Back 31

On a reverse fault, a hanging wall moves up as a result of compression.

Front 32

What does this symbol mean?

Back 32

Horizontal beds

Front 33

What does this symbol mean?

Back 33

Overturned beds

Front 34

What does this symbol mean?

Back 34

Vertical bed.

Front 35

Syncline or anticline?

Back 35

Syncline

Front 36

Syncline or anticline?

Back 36

Anticline

Front 37

Name a Precambrian eon

Back 37

Proterozoic

Archean

Hadean

Front 38

Name the present-day eon

Back 38

Phanerozoic

Front 39

Describe the difference between weathering and erosion.

Back 39

Weathering is chemical or mechanical breakdown in situ, erosion is the movement of those particles.

Front 40

Describe the economic significance of laterite soils.

Back 40

Laterite soils are rich in iron and aluminum.

Front 41

Describe how a residual soil underlain by limestone differs from that of basalt.

Back 41

A soil underlain by limestone will be rich in calcite, while a soil underlain by basalt will be rich in iron.

Front 42

What geologic feature does this represent?

Back 42

Dome

Front 43

What geologic feature does this represent?

Back 43

Plunging syncline.

Front 44

What geologic feature does this represent?

Back 44

Dextral strike-slip fault

Front 45

What geologic feature does this represent?

Back 45

Sinistral strike-slip fault

Front 46

What geologic feature does this represent?

Back 46

Asymmetric syncline

Front 47

What geologic feature does this represent?

Back 47

Symmetric anticline

Front 48

What geologic feature does this represent?

Back 48

Normal dip-slip fault

Front 49

What geologic feature does this represent?

Back 49

Reverse dip-slip fault

Front 50

What type of fault would tension stress usually result in?

Back 50

Tension stress would normally produce a normal dip-slip fault.

Front 51

What type of fault would compression stress normally result in?

Back 51

Compression stress would normally produce a reverse dip-slip fault.

Front 52

What type of fault would shearing stress normally result in?

Back 52

Shearing stress would normally produce a strike-slip fault.

Front 53

What is the name of the chemical process by which feldspars decompose to clay?

Back 53

Feldspars decompose to clay via hydrolysis.

Front 54

What is the chemical process by which anhydrite alters to gypsum?

Back 54

Anhydrite alters to gypsum via hydration.

Front 55

What is the chemical process by which calcite weathers?

Back 55

Calcite weathers via dissolution.

Front 56

What sedimentary rock underlies the Stevens Point area?

Back 56

Stevens Point and the surrounding area is underlain by quartz and sandstone.

Front 57

Which two erosional agents produce well-sorted sediment?

Back 57

Wind and water produce well-sorted sediment.

Front 58

Which two erosional agents produce poorly-sorted sediment?

Back 58

Gravity and glaciers produce poorly-sorted sediment.

Front 59

What is the most likely possible environment in which hematitic stiltstone may be produced?

Back 59

Hematitic stiltstone is often produced in a flood plain environment.

Front 60

What is the most likely possible environment for rock salt to be produced?

Back 60

Rock salt is likely to be produced in a desert environment.

Front 61

What is the most likely possible environment for quartz sandstone to be produced?

Back 61

Quartz sandstone is likely to be produced in a beach environment.

Front 62

What is the most likely possible environment for chalk to be produced?

Back 62

Chalk is most likely to be produced in a marine environment.

Front 63

What is the most likely possible environment for breccia to be produced?

Back 63

Breccia is most likely to be produced in a talus slope environment.

Front 64

What is the most likely possible environment for coal to be produced?

Back 64

Coal is most likely to be produced in a swamp environment.

Front 65

What is the most likely possible environment for coquina to be produced?

Back 65

Coquina is most likely to be produced in a marine environment.

Front 66

What is the most likely possible environment for conglomerate to be produced?

Back 66

Conglomerate is most likely to be produced in an alluvial fan environment.

Front 67

What is the protolith of hornfels?

Back 67

Shale is hornfels' parent rock.

Front 68

Name the four most common folated rocks from low grade to high grade.

Back 68

Slate

Phylite

Schist

Gneiss

Front 69

Name the three eras of the Phanerozoic Eon

Back 69

1. Paleozoic Era

2. Mesozoic Era

3. Cenozoic Era

Front 70

Name three major resource aspects of sedimentary rocks.

Back 70

1. Ore deposits

2. Aquifers

3. Fossil fuels

Front 71

Name sedimentary rocks that make good aquifers or reservoirs.

Back 71

Sandstone

Conglomerate

Carbonate

Front 72

Name mechanical weathering processes.

Back 72

Frost action

Abrasion

Pressure reduction

Organic activity

Thermal expansion

Front 73

Name three types of unconformities

Back 73

1. Disconformity

2. Angular unconformity

3. Nonconformity

Front 74

Describe "disconformity"

Back 74

Disconformity describes when:

1. Sedimentary layers of similar orientation occur above and below a stratigraphic horizon; however, a significant time gap exists between them.

2. Older sedimentary rocks overlain by much younger sedimentary rocks of the same orientation.

Front 75

Describe "angular unconformity"

Back 75

Angular unconformity describes when older inclined sedimentary rocks overlain by much younger sedimentary rocks with a significantly different dip angle.

Front 76

Describe "nonconformity"

Back 76

Nonconformity describes when younger sedimentary rocks overlie older crystalline rocks consisting of either igneous or metamorphic rocks.