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Final Flashcards

1
Q

What is geology?

A

the study of the Earth

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2
Q

What is the scientific method and what is its purpose?

A

An objective, systematic method used to understand natural phenomenon.

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3
Q

Be able to understand the steps involved in the scientific method

A

Step one: observation, problem or research question; step two: hypothesis; step three: experiment and hypothesis revision; step four: peer review, publication and replication; step five: theory development

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4
Q

Define the following terms: hypothesis, scientific theory, scientific law. Make sure you understand the difference between a theory and a law.

A
  1. Hypothesis: a tentative, testable explanation of a observations. Has some support, but has yet to be held to intense, scientific scrutiny.
  2. Theory: the best explanation of a natural phenomenon that is supported by a wide range of data. “all data agree” have been subjected to intense scientific testing. All other explanations have been falsified.
  3. Law: a statement or equation that simply states a natural relationship.
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5
Q

What are the principles of plate tectonics?

A

The lithosphere is broken down into numerous plates; these plates move on top of the underlying asthenosphere; the plates move very slowly; the plates interact at plate boundaries, generating geologic activity, the geologic activity is concentrated at plate boundaries

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6
Q

What are the three types of plate tectonic boundaries and how do plates move relative to each other at these boundaries?

A

Convergent: lithospheric plates move toward each other
Divergent: lithospheric plates move away from each other
Transform: lithospheric plates slide past each other

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7
Q

What are minerals?

A

Inorganic, solid, naturally occurring, crystalline structure, well defined chemistry (that can vary within limits)

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8
Q

What is the difference between rocks and minerals?

A

Rocks: aggregates of minerals, glass or pieces of rock, collection of minerals crystals; coherent solid, naturally occurring.
Minerals: inorganic crystals that occur in nature and building blocks of most rocks, continuous crystals

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9
Q

Know the silicate class of minerals: their importance, their principle anionic group, and the silica tetrahedra

A

The majority of rocks on Earth are considered silicates (quartz and olivine) anionic group : SiO4 4-; minerals in the same class commonly exhibit similar properties; silica tetrahedra is the building block of silicates;

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10
Q

What are the 3 rock groups and how do they differ?

A

Sedimentary: debris cemented from preexisting rock
Igneous: cooled from a liquid (melt)
Metamorphic: rock altered by pressure and temperature

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11
Q

What are the two types of weathering and how do they work together to break down rock?

A

The physical breakdown of rock into smaller pieces. Chemical reactions breakdown rock and minerals. Involves the alteration of mineral crystalline structures. Produces material stable at Earths surface; more efficient when water is in the environment.
Work together: physical weathering produces more surface area allowing more of the rock exposed to the elements, chemical weathering produces products that can be easily transported and breaking it down into new minerals

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12
Q

What are sedimentary rocks and what are the three different categories of sedimentary rocks?

A

Form at or near the Earths surface; clastic: deposition, accumulation, and lithification of rock fragments; chemical: precipitation of minerals from a solution or by an organism; organic: accumulation and alteration of plant matter before decay.

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13
Q

How are clastic sedimentary rocks formed?

A

Weathering: generation and removal of clasts/chemicals from parent rock; erosion/transportation: dispersal by wind, water, ice and gravity; deposition: settling out of the transporting fluid, formation of crystals; burial; lithification and diagenesis: transformation into solid rock and alteration of sediment

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14
Q

What is the most common mineral in a sedimentary rock and why is it so common?

A

Quartz because it is the most resistant to weathering

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15
Q

what is metamorphism?

A

process by which a protolith alters when it experiences a change in pressure, temperature, and or stress

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16
Q

Describe the processes of metamorphism: recrystallization, neocrystallization, phase change, and plastic deformation. How do these processes change the minerals and/or textures of a rock?

A

*Recrystallization: minerals in the protolith grow and change shape – clastic textures become crystalline textures, fossils recrystallize into quartz or calcite
*Neocrystallization: chemical reactions between minerals result in new minerals; generates new minerals not originally in the protolith
*Phase change: minerals within the photolith transition into polymorphs – the new polymorphs are stable at metamorphic conditions
*Plastic deformation: rock changes shape without breaking or melting, results when rock undergoes squeezing and smearing at depth

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17
Q

What is a differential stress?

A

Stress/force greater in one orientation; differential stress is a common result of tectonic plate interaction; commonly occurs with pressure and temperature

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18
Q

What is a foliation? What can a foliation tell a geologist about the metamorphic/tectonic environment?

A

Has preferred orientation of long or platy minerals; subjected to differential stress; classified by composition, grain size, and foliation type

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19
Q

How are metamorphic rocks classified? You should know the basic types of foliation and foliated metamorphic rocks. You should know the basic types of non-foliated metamorphic rocks.

A

*Foliated rocks: shale, phyllite, schist, gneiss
*Nonfoliated: quartzite, marble,

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20
Q

Describe how a shale protolith undergoes metamorphism to become a slate, phyllite, schist, and gneiss.

A

*Low grade: shale protolith –> slate –> phyllite. Clays recrystallize larger, aligned clays to yield a slate, clays break down chemically react and form tiny aligned micas in a phyllite
*Intermediate grade: phyllite –> schist. Micas grow larger to form a schist, other minerals break down, chemically react to form new minerals grow in the schist.
*High grade: schist –> gneiss. Micas break down, chemically react; elements recombine into new minerals

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21
Q

What is pressure (confining/lithostatic) and how does it differ from a differential stress?

A

Confining stress: force is equal in all directions, pressure will increase with depth due to overburden but the forces will remain equal
Differential stress: stress 1 always has the highest magnitude by default, stresses can affect rock in different directions caused by tectonic forces, they are always perpendicular from each other

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22
Q

What are the three types of differential stress? Be able to describe them and understand the tectonic environments in which they occur.

A

COMPRESSION: Common at convergent plate boundaries, results in: lateral (horizontal) shortening, vertical thickening
TENSION: Common at divergent plate boundaries, continental rift zones, results in: lateral lengthening, vertical shortening
SHEAR: Common at transform boundaries, results in: smearing of rock

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23
Q

Understand the link between deformation and metamorphism.

A

Deformation: the result of stress; displaced: change in location; rotated: change in orientation; distorted: change in shape (strain); rock has been metamorphosed, rock has been folded and faulted

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24
Q

Describe elastic and permanent deformation.

A

*Permanent: deformation that remains in rock (is preserved) after the stress is removed, generates structures (features, generated by deformation)
*Elastic: deformation will occur when the rock experiences stress, but the rock goes back to its original shape once stress is removed

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25
Q

Describe brittle and ductile deformation.

A

Brittle: rocks respond by breaking, common in upper crust, all brittle deformation is permanent
Ductile: rocks respond by bending, common in deeper crust, associated with metamorphism, ductile deformation can be elastic or permanent

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26
Q

Describe how rock composition, temperature/pressure, and deformation rate influence if a rock will deform brittlely or ductily

A

Shallow crust (lower p & t) = brittle; deeper crust (higher p & t) = ductile
Faster rate = brittle; slower rate = ductile
When exposed to the same p & t conditions some rocks will deform brittely while others will deform ductility

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27
Q

What is a normal fault?

A

Common in tensional environments, hanging wall block moves down in response to tectonic stretching and gravity

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28
Q

What is a reverse fault?

A

Common in compressional environments, hanging wall block moves up, relative to the footwall block

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29
Q

What is a thrust fault?

A

Fault is gently inclined 30 degrees or less, generates a fold

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30
Q

What is a strike-slip fault?

A

No hw no fw, lateral motion only (no vertical motion)

31
Q

What is a fold? Are folds brittle or ductile forms of deformation?

A

Fold: bend within layers of rock; ductile

32
Q

What is an anticline?

A

Arch shaped, limbs dip away from hinge, age of rock: oldest within the folds interior, youngest along the exterior

33
Q

What is syncline?

A

Valley shaped, limbs dip toward the hinge, age of rock: youngest within the folds interior, oldest along the exterior

34
Q

What is an earthquake and how are most earthquakes generated on Earth?

A

Ground shaking due to a sudden release of energy, this energy radiates and expands outward as waves, majority are caused by motion along a brittle fault in associated with plate tectonic boundaries

35
Q

What is an epicenter?

A

Point, on the earths surface directly above the hypocenter

36
Q

What is a hypocenter/focus?

A

Location, along the fault, where earthquake energy is released, this is the location where movement along the fault is occurred

37
Q

Crust: continental and oceanic (what are they made of and how they differ, the two most abundant elements in the crust)

A

1.Continental crust: wide variation of rock types, chemistry is felsic made of granite, less dense, older (cannot be recycled), 20-70 km thick.
2.Oceanic crust: low variation of rock types, made of mafic igneous rock basalt and gabbro, more dense, younger (gets recycled), 3-10 km thick.
3.Oxygen and silicon

37
Q

Mantle: (what is the mantle made of; is it a solid, liquid, or a gas?; what are the different zones of the mantle and how do they differ?; you must know what the asthenosphere and lithospheric mantle are)

A

1.Lower mantle: very dense rock, density increases with depth. Made of peridotite – ultramafic rock.
2.Lithosphere: lithospheric mantle + crust it is a strong/rigid solid
3.Asthenosphere: weak solid

37
Q

Core: Inner and outer (what are they made of and how they differ)

A

Inner is solid iron
Outer is liquid iron – responsible for earths magnetic field

37
Q

What are foreshocks, mainshocks, and aftershocks?

A

Mainshock: a major earthquake
Foreshocks: smaller magnitude earthquakes that precede the mainshock
Aftershocks: usually follow a large earthquake

37
Q

Discuss and explain stick-slip behavior in terms of earthquake generation.

A

Energy is created when rock along faults move, movement is not gradual but as jumps; stick conditions: rock blocks along a fault can not move due to friction; slip conditons: stress overcomes friction and causes rock to suddenly move in a jolt generates seismic energy and decreases stress

37
Q

What is EQ Magnitude?

A

Measurement of the amount of energy released during the earthquake

37
Q

What are P-Waves? How do they move particles/atoms? Through which types of matter can they travel?

A

Waves travel by compressing and expanding material on a molecular level, material moves back and forth parallel to wave direction, p waves are the fastest, they travel through solids, liquids, and gases

38
Q

What is EQ Intensity?

A

How much did the earthquake destroy

38
Q

What are S-Waves? How do they move particles/atoms? Through which types of matter can they travel?

A

Waves travel by moving material back and forth perpendicular to wave direction, s waves are slower than p waves, they travel only through solids

39
Q

What is the Moment Magnitude scale and what does it measure?

A

Estimation of energy released, uses wave amplitudes, how much rock moved along the fault and rock strength

40
Q

What is the Mercalli Scale and what does it measure?

A

A qualitative earthquake scale, from I-XII, of the degree of shaking in an earthquake.Measures damage caused by shaking, observations and first hand accounts

41
Q

State and explain the 4 factors that influence a location’s Mercalli scale ranking during an earthquake.

A

Earthquake magnitude: larger the magnitude then the higher ranking on scale, Location from the epicenter: closest to the epicenter then the more damage, building materials: The flexibility of a building material determines its resistance to earthquake damage, surface materials

42
Q

Describe deformation and earthquakes at subduction zones, continental collision, divergent, transform. Know what kind of stresses are dominant, what kind of faults are dominant, the potential magnitude earthquakes, and earthquake depth:

A

-SUBDUCTION ZONE: occurs in shallow, intermediate, and deep depth, compressional stresses and thrust faults. high magnitude.
- CONTINENTAL COLLISION: earthquakes are generally shallow, but can be powerful, compressional stresses and thrust faults.
- DIVERGENT PLATES: tensional stress and normal faults, shallow quakes, generally lower magnitude. continental rifts and mid ocean ridges produce moderate earthquakes.
- TRANSFORM PLATES: dominated by shear stress and strike slip faults – sets of strike slip fault move rock, shallow quakes, generally low to high magnitudes

43
Q

What is a mega thrust fault and where (what type of plate boundary) do they occur? Why are megathrust faults dangerous?

A

High magnitude earthquakes commonly shallow, subduction zones, they cause massive destruction and tsunamis

44
Q

What is a stream?

A

Any ribbon of water that flows downhill (gravity) within a channel

45
Q

What is groundwater? Why is groundwater important?

A

Water stored beneath earths surface, open spaces in rock or sediment, majority of liquid freshwater

46
Q

What is a stream load? What are the 3 types of load?

A

*Sediment load: sediments that are moved by stream water; clasts, charged atoms
*Bed load: sediments are transported along the channel bed in a process called saltation
*Suspended load: seds are transported while floating in the water
*Dissolved load: sediments (ions) are transported while dissolved in the water

47
Q

What is saltation? Describe the process of saltation.

A

The process by which clasts/sediments in the bed load are transported as they are periodically propelled into stream water

48
Q

What is a meandering stream? What is a meander?

A

The stream channel shape; the bend;

49
Q

What is a thalweg?

A

Fastest flowing current of water in a stream channel, located where friction, acting on the water, is at its lowest

50
Q

What is a point bar? What is a cut bank? Make sure you can locate them along a stream channel.

A

*Point bar: areas of deposition along a stream channel
*Cutbank: areas of erosion along a stream channel

51
Q

What is a pore?

A

Open voids within a rock

52
Q

What is permeability? What is permeability dependent upon?

A

Materials ability to transmit the flow of water; dependent upon: porosity and interconnections between pores

53
Q

What is the ground water table?

A

A boundary between the saturated zone and unsaturated zone

54
Q

What is the saturated zone? Where is it with respect to the water table?

A

Where pores are completely filled with water; water flows under the influence of: gravity and pressure of overlying groundwater. Beneath the water table

55
Q

What is the unsaturated zone? Where is it with respect to the water table?

A

Where pores are void or partially filled with water; water flows downward under the influence of gravity. above the water table

56
Q

What is an aquifer? Aquitard? What are the characteristics of an aquifer or aquitard? Give examples of aquifers and aquitards.

A

*Aquifer: rock layers, sediments that permit the flow of water, high porosity and permeability.Ogallala
*Aquitard: rock layers, sediments that DO NOT permit the flow of water. shales & clay

57
Q

What is urbanization and how and why does it affect flooding?

A

Urbanization is the process by which humans take permeable surfaces and replace it with impermeable, this influences flooding to be intensive and to flood quickly

58
Q

In what ways does overuse affect groundwater and stream water?

A

Rivers can run dry; overuse of groundwater can cause land to sink (subsidence)

59
Q

What is subsidence and How and why does subsidence occur due to overuse of groundwater (be sure you can explain the process!)

A

Heavy irrigation causes groundwater to be used a lot, pore pressure is being lost so sediments compact together and decrease porosity which causes land subsidence. This problem is permenant.

60
Q

What is porosity? What porosity dependent upon?

A

The volume of open spaces (pores) in the rock. Groundwater is stored in the pores

61
Q

Both the Richter and Moment Scales are logarithmic. What does this mean?

A

The richter scale is based on powers of 10. Moment scale depicts the absolute size of earthquakes, both scales are used for reporting earthquake magnitude.

62
Q

Describe metamorphism at the following environments: continental continental mountain building, subduction zones, surrounding magma chambers.
What are the metamorphic agents and conditions (high grade or low grade, high or low Pressure, high or low temperatures, presence of a differential stress)?

A
  • CONTINENTAL CONTINENTAL MOUNTAIN BUILDING: collision of plates result in the uplift and burial of rock, agents: pressure temperature, differential stress from low to high grade.
  • SUBDUCTION ZONES: metamorphism of oceanic crust, high pressure lower temps, because oceanic crust is cold, metamorphic agents: pressure, temp, differential stress – trench: high pressure, low temp; subducting slab: high pressure moderate temp.
  • SURROUNDING MAGMA CHAMBERS: magma body –> country rock –> heat metamorphoses country rock. agents: temperature low grade to high grade, the closer the rock is to the magma chamber the higher metamorphisis grade, high temp low pressure,
63
Q

What is meant by “metamorphic grade”? And how does metamorphic grade change when a rock is progressively buried?

A

Metamorphic grade refers to the range of metamorphic change a rock undergoes

64
Q

Know the agents of metamorphism discussed in class: pressure, temperature, differential stress

A

Confining/lithostatic pressure: when a rock is exposed to equal forces at all angles – stress: a force that acts upon an area, magnitude increases with depth.
Temperature: metamorphic temps are between diageneisis and melting, increases with depth, cause atoms to vibrate rapidly, breaking and bending bonds, atoms band move and bond with neighbors

65
Q

What is a protolith? What kind of rocks can be protoliths?

A

The rock that undergoes metamorphism to become a metamorphic rock

66
Q

What are the two factors that influence eruption style of a volcano?

A

volatile content and viscosity. magma rises and experiences a decrease in pressure, this causes volatiles to escape and form gas bubbles. This increases bouyance allows magma to rise more repeating the whole process until the gas bubble burst causing an eruption. more volatile = more explosive.

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