Geology Unit 2

Front 1

Where is Tectonic activity: plate boundaries vs. interior? What kind happens in different places?

Back 1

Tectonic activity takes place at plate boundaries. There are deeper earthquakes/more tectonic activity at subduction zones and less tectonic activity at divergent boundaries.

Front 2

What is orogenesis, what happens during orogenesis?

Back 2

Orogensis is mountain building. During it rocks undergo DEFORMATION, when they are squashed, stretched bent or broken

Front 3

What is deformation and what causes it?

Back 3

Deformation is the change in configuration of a body of material in response to stretching, squeezing, sheering into a new configuration

Front 4

Understand what stress and strain are, how stress can cause strain. Be sure to know the differences between stress and strain.

Back 4

Stress is the force applied to a surface per unit area. strain is the change in shape of a material from its original shape to a new shape, caused by stress

Front 5

What are the different types of stress? What about strain?

Back 5

Different types of stress- confining pressure, differential stress (compression-rock is squeezed, tension-rock is pulled apart, shear stress-1 side of a rock is pushed sideways past another), fluid pressure (counteracts stress).
Different types of strain: stretching/elongation- rock layer becomes longer in direction of interest, shortening/contraction-rock layer becomes shorter in direction of interest, shear strain (movement of one part of the rock body past another)

Front 6

Understand the transition from brittle to ductile behavior in rocks, and how burial and increasing temperature and pressure influence mechanical behavior

Back 6

Brittle rocks break into more than two pieces, while Ductile rocks change shape. High pressure, hot rocks are ductile, while low pressure cold rocks are brittle. Rocks with slow deformation rate are ductile. Halite is ductile, granite is brittle. At first, rocks get stronger (more ductile) with depth but then they get weaker deep in the crust.
composition- halite = ductile, granite= brittle

Front 7

Know the components of a fault, be able to describe it’s architecture

Back 7

A fault is composed of a fault zone, a hanging wall (where a miners head would be), and the footwall (where a miners feet would be.

Front 8

joints

Back 8

fracture in rock, crack where rock pulled apart:formed by burial and tectonic forces, or cooling and contraction or unloading

Front 9

faults

Back 9

planar fractures on which sliding has occurred, rocks have slipped past one another: creates earthquakes, active @ plate boundries
tip of fracture = very unstable, creates zone of plastic deformation

Front 10

Veins:

Back 10

fractures filled in with minerals: formed by filling in open voids or fluids pushing open rock to create space

Front 11

Stress

Back 11

the amount of force divided by the area on which the force is applied

Front 12

Strain

Back 12

change in shape or volume of a body as a result of stress

Front 13

Orogenesis

Back 13

the formation of mountains or the time period during which tectonic activity causes deformation and forms mountains.

Front 14

Differential stress

Back 14

a condition with unequal stresses from different directions.

Front 15

Fluid Pressure

Back 15

pressure from water in pore spaces that pushes outward in all directions and opposes the inward-directed confining pressure on the rock

Front 16

How do you describe the orientation of a plane? What is strike and dip?
a

Back 16

strike- the line formed by the intersection of a plane and the horizon
dip- steepest angle of descent between the plane and the horizon, 90 degrees from strike, direction that water flows down slope

Front 17

How are faults classified?

Back 17

based on orientation of hanging wall and footwall motion

Front 18

What is Dip slip vs. Strike slip? How is a normal fault different from a reverse fault or a strike slip fault? What sort of strain results from different faults?

Back 18

dip slip: sliding occurs up or down the slope of the fault, up or down dip direction
strike slip: one block slides past the other parallel to the line of strike, fault moving in direction of strike, horizontal
oblique slip: faults move diagonally across the fault plane (mix or strike and dip)

Front 19

Be able to identify normal vs. reverse vs. strike slip faults

Back 19

normal: hanging wall moves down in relation to the footwall, crust is extended and sometimes thinned
reverse/thrust: hanging wall moves up relative to the footwall, SHORTENING

Front 20

Understand Fold Terminology-Limb, Hinge, ect.

Back 20

folds- curved rock layers, type of DUCTILE deformation
hinge zone:section of the fold with the tightest curvature
limb: planar or less curves sections of a fold
anticlines: folds with and arch like shape (A)
Synclines: folds with a trough shape, (U or V)

Front 21

Subduction

Back 21

is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate and sinks into the mantle as the plates converge.

Front 22

Continental Collision

Back 22

is a phenomenon of the plate tectonics of Earth that occurs at convergent boundaries.Regions where this process occurs are known as subduction zones.

Front 23

Hotspots

Back 23

is a location on the Earth's surface that has experienced active volcanism for a long period of time.

Front 24

Craton

Back 24

the old, low density, stable part of continents, usually rocks found in center of continents, lowest density of continental crust. the stable interior portion of a continent

Front 25

Oceanic trench

Back 25

a type of thin, mafic crust that underlies the ocean basins.

Front 26

Accretionary Prism

Back 26

is formed from sediments that are accreted onto the non-subducting tectonic plate at a convergent plate boundary. accretionary prism forms along the subduction zone

Front 27

Geologic Terrane

Back 27

as distinct from the more general topographic term 'terrain', is a crustal block or fragment that is typically bounded by faults and that has a geologic genesis distinct from those of surrounding areas.

Front 28

What do normal, strike slip, and reverse faults do to the crust? Which faults cause extension? What about shortening?

Back 28

normal faults extend and sometimes thin the crust
reverse faults shorten crust

Front 29

What is continental accretion?

Back 29

material that is too buoyant to subduct is attached to the continent
process through which material is added to continents, occurs during mountain building, subduction and collision, also when erosion causes deposition of new sediments into plate margins

Front 30

How do continents grow?

Back 30

Through continental accretion of exotic terranes and can become thicker or thinner over time.

Front 31

Where does brittle deformation take place within the earth? What about ductile deformation?.

Back 31

brittle near surface, ductile within earth (mantle) because there it’s hotter and there’s more pressure

Front 32

How does the strength of the earth vary with depth? Why does this change?

Back 32

At first, rocks get progressively stronger (from brittle to more ductile) with depth but then they get weaker deep in the crust. This changes because of differences in pressure and temperature within the earth.

Front 33

What controls regional elevation?

Back 33

Understand the different ways mountain belts are created and regional elevation is built up
Regional elevation is controlled by continents become thicker or thinner over time. Regional elevation is built up from if the crust is shortened, if more material is added through igneous processes, and heating. Mountain belts are created by subduction, continental collision, and mantle upwellings.

Front 34

Know how elevation is decreased

Back 34

normal faulting stretch and thins the crust. Erosion can move material from thick/high areas to thin/low areas. when rocks cool they become thinner``
crustal thinning/regional lows are caused by extension of the lithosphere

Front 35

Where do you find mountain belts? What are the plate tectonic settings? What processes occur in different tectonic settings (think accretion or addition of magma)

Back 35

Mountain belts are found along convergent plate boundaries. In an oceanic subduction zone, magma and material are added by accretion, thickening the crust. As slab pull pulls the subduction plate down into the subduction zone, an oceanic trench forms.
Environments- subduction, continental collision, mantle upwellings,

Front 36

Subduction of Oceanic Crust

Back 36

crust thickened by addition of magma, also thickened by shortening & material also added by accretion. As the slab-pull force pulls the subjecting plate down into the subduction zone, OCEANIC trench forms. Horizontal compression leads to strain and formation of thrust faults. Accretionary prism forms along subduction zone. Magma rises from melting of sub ducting slab and is emplaces in the plate

Front 37

Continental Collision

Back 37

high elevation bc one continent tries to subduct under the other, this cant happen so the they become sutured and thickness of crust is doubled. Results in significant accretion. The interiors of collisional mountain belts = significant metamorphism
thrust fault thicken the crust, even behind collision zone, stresses can be very high, causes a lot of strain

Front 38

Mantle Upwelling

Back 38

lead to regional heights, usually prelude to rifting, occur at hot spots

Front 39

What is an exotic terrane and how does this build new continental crust? How does this influence continental formation?

Back 39

An exotic terrane is a new rock that is added to a region by accretion that comes from another place.

Front 40

What is a hotspot?

Back 40

volcanic areas above rising mantle plumes, the mantle convects, when it rises hot spot can form. eg Hawaii. Hotspots around yellowstone

Front 41

Understand how a rift forms and how this is different from a hot spot (it is different)

Back 41

A rift forms from lithospheric stretching . As opposed to a hotspot, rifts form when the mantle upwells as a result of crustal thinning, not convection.

hot spots CAN evolve into rifts. Pieces of material are added to continents through accretion and are pulled away during rifting

Front 42

What can change local elevation?

Back 42

not every mountain is part of a regional mountain belt, elevation highs can be caused by a variety of factors: thrust, normal
folding can create local mountains, biggest impact on erosion

Front 43

How does erosion cause local mountains?

Back 43

erosion is the most important factor in controlling topography,break off excess material/rock helping to eventually form local mountains. Resistant rock forms hills, softer rock forms valleys from erosion.

Front 44

What is a rift basin? What about a flexural basin?

Back 44

rift basin- sediments deposited into low areas as lithosphere is pulled apart.Caused by continental rifting and normal faulting
Types of Rift Basins: continental rifting and normal faulting can cause the development of basins, small ones occur at each normal fault
Flexural Basin- lithosphere flexes bc of mass of mountains, sediments fill gaps
Types of Flexural Basin- Foreland basins occur when lithosphere is flexed bu the weight of a mountain belt
Passive margins occur when a continental plate sits next to an oceanic plate. as sediment piles up at this boundary, the plates flex allowing for more room

Front 45

Epicenter

Back 45

the point on Earth’s surface directly bove where an earthquake occurs

Front 46

Hypocenter

Back 46

the place where an earthquake is generated

Front 47

Elastic Strain

Back 47

the ability of a material to strain a small amount and then return to its original shape when the stress is decreased

Front 48

Seismic Wave

Back 48

elastic waves produced by earthquakes or generated artificially

Front 49

S-Wave (Secondary Wave)

Back 49

a seismic body wave propagated by a shearing motion that involves movement of material perpendicular to the direction of propagation an S wave cannot travel through magma and other liquids.

Front 50

P-Wave (Primary Wave)

Back 50

a seismic body wave that involves particle motion, consisting of alternating compression and expansion, in the direction of propagation.

Front 51

Surface Wave

Back 51

seismic waves that travel on Earth’s surface

Front 52

Seismometer

Back 52

sensitive digital instruments that are able to precisely detect a wide range of earthquakes

Front 53

Tsunami

Back 53

a large sea wave produced by uplift, subsidence, or some other disturbance of the seafloor, especially by a shallow submarine earthquake.

Front 54

Earthquake

Back 54

sudden movement of earth caused by the abrupt release of energy

Front 55

What is an Earthquake? What are seismic waves?

Back 55

An earthquake is a release of seismic energy in the earth. Seismic waves release mechanical seismic energy.
connection to plate tectonics caused by normal faults, reverse & thrust faults, strike slip fault
release of seismic energy in the earth, usually this happens when stored energy rocks is released when the rocks break. Most caused by the bild up of spress alond a fault, resulting in a rupture and slip.
Seismic energy is a type of mechanical energy that is released in waves, they radiate outward from hypocenter

Front 56

How do earthquakes cause tsunamis?

Back 56

Tsunami’s form from fault related earthquakes on the seafloor. Fault movement uplifts or down drops the seafloor.

Front 57

What are the different ways that seismic waves can be generated? Which way produces the biggest earthquakes?

Back 57

Seismic waves can be generated by normal/reverse/ strike slip faults, volcanoes, landslides and explosions. The biggest earthquakes are produced by the buildup of stress along a fault.

Front 58

What elastic rebound? Give a real life example?

Back 58

stress applied to an object transfers energy to it (why earthquakes occur). If elastic strain energy overcomes the strength of a material, it breaks and rebounds to its original shape. Stress increase causes elastic strain to increase. A real life example can be seen with a rubber band.
FAULT- rock breaks when stress overcomes strength

Front 59

Explain what happens to rock before, during, and after an earthquake occurs in terms of stress and strain

Back 59

stress increase causes elastic strain to increase. Eventually material ruptures (earthquake).
Before- stress increases, elastic strain (Rising part of graph)
During- fault slips causes earthquakes (top curve of graph)
After- stress drops, post-slip recovery of elastic strain & cycle starts again. (bottom/ end of graph)

Front 60

Where do earthquakes start?

Back 60

starts as small patch below surface @ hypocenter (focus), migrates out, ruptures surface (fault scarp), fault scarp lengthens.

Front 61

Understand the systems that produce earthquakes (MOR, Subduction, Collision). Where do these earthquakes occur (how deep and where in the plate)? How big are the earthquakes?

Back 61

Subduction zones produce the largest earthquakes and mid ocean ridges produce small earthquakes.

Front 62

How are earthquakes monitored? What equipment is used? What does it measure?

Back 62

Seismometers measure seismic waves, record amount of shaking that occurs during an earthquake. They are placed in the ground and measure vibrations. One could also triangulate the epicenter to estimate distance, or measure s-wave amplitude.

Front 63

What are the different types of seismic waves? How are they different?

Back 63

Surface waves- horizontal surface wave shears material side to side
vertical surface wave shears material up and down
only travel along surface of earth
Body waves- Primary body wave (P-Wave) compresses and expand
material, FASTEST. Compressional, push atoms closer together in the direction they’re moving.
Secondary Body Wave (S-Wave) shears material, FASTER, shear material up & down or side to side
body waves move through EARTH

Front 64

Why can’t s-waves move through liquid?

Back 64

S-Waves depend on a resistance to shear, which doesn’t exist in a liquid

Front 65

How do we triangulate earthquake epicenters?

Back 65

By measuring the time between the arrival of the first P-Wave and the arrival of the first S-Wave.

Front 66

Understand wave refraction and reflection-be able to figure out which way a wave will bend at a boundary

Back 66

A seismic wave bends as it travels through faster or slower material. From fast to slow, it undergoes a steep refraction, from slow to fast, it’s much more subtle of a change (not steep), and when rising from fast to slow, it continues on the same path that it was initially on.

What do seismic waves tell us about the earth’s interior?
Seismic waves tell us about the density of certain parts of earth’s interior. Based off of the way they refract, we can figure out if they’re travelling fast (through less dense material) or slow (through more dense material)

Front 67

Angular Unconformity

Back 67

an unconformity (ancient erosion surface) in which the older, underlying strata dip more steeply or at a different angle than the younger, overlying strata

Front 68

Nonconformity

Back 68

an unconformity in which the older rocks below the unconformity are not layered

Front 69

Disconformity

Back 69

an unconformity in which the bedding planes above and below the break are essentially parallel, but the unconformity surface records erosion or some other interruption in the deposition of layers

Front 70

Isotope

Back 70

one or two or more species of the same chemical element but differing from one another by having a different number of neurons

Front 71

Radioactive Decay

Back 71

the spontaneous disintegration and emission of particles from an unstable atom

Front 72

Half-life

Back 72

in radioactive decay, refers to the time it takes for half of the parent atoms to decay into a daughter product

Front 73

Parent Isotope

Back 73

an isotope before it undergoes radioactive decay

Front 74

Daughter Isotope

Back 74

the element produced by radioactive decay of a parent atom

Front 75

Relative vs. Absolute Dating

Back 75

Relative dating refers to the order in which events happen, while absolute dating refers to the specific time in which an event took place (the age of events).

Front 76

Know the principles of geology and relative dating and what they mean

Back 76

The principle of inclusion refers to how younger rock can contain pieces of older rocks. The principle of altered contacts refers to the fact that younger rocks can cause changes along their margins. Also remember the principles of uniformitarianism, superposition, cross-cutting relationships, and horizontality.

Be able to determine relative age from cross cutting relationships

Front 77

What are the different types of unconformities?

Back 77

A nonconformity separates a layered surface from a non layered surface (a non layered rock uplifted and eroded with igneous rocks deposited on top).
An angular unconformity refers to the contact that separates a younger gently dipping rock unit from underlying rocks that are tilted layered rocks.
A disconformity separates two layered sections.

Front 78

How are fossils preserved?

Back 78

by shells, bones, replacements, casts, molds, impressions and amber.

Front 79

How can we use fossils to determine age of rock?

Back 79

The rock record. Fossil rich sedimentary rocks reveal patterns of evolution and extinction

Front 80

What is stratigraphic correlation? Be able to do a basic correlation

Back 80

Tracing layers of rock from place to place. Can be lithologic (based on rock), chemical (based on chemical composition), or time (based on age)

Front 81

What is an isotope?

Back 81

An atom with same number of protons, but a different number of neutrons.

Front 82

Be able to use half-life and parent and daughter isotope information to determine age. (Basic equation will be given)

Back 82

(Starting amount) x ½^(# of half lives)=(Ending amount)
(Time for each half life) x (# of half lives

Front 83

What can radiometric dating determine?

Back 83

The age of the rock

Front 84

What assumptions are used for radiometric dating?

Back 84

Rock/mineral composition has not been altered, No daughters present when rock formed

Front 85

Hydrosphere

Back 85

is the liquid water component of the Earth. It includes the oceans, seas, lakes, ponds, rivers and streams.

Front 86

Hydrologic Cycle

Back 86

the sequence of conditions through which water passes from vapor in the atmosphere through precipitation upon land or water surfaces and ultimately back into the atmosphere as a result of evaporation and transpiration

Front 87

Runoff

Back 87

is the flow of water that occurs when excess stormwater, meltwater, or other sources flows over the earth's surface.

Front 88

Drainage Basin

Back 88

an area in which all drainages merge into a single stream or other body of water

Front 89

Discharge

Back 89

the volume of water flowing through some stretch of river or stream per unit of time

Front 90

Hydrograph

Back 90

a graph showing the change in the amount of flowing water

Front 91

Sediment Capacity

Back 91

total amount of sediment that a stream is able to transport

Front 92

Suspended Load

Back 92

fine particles, generally clay and silt, that are carried suspended in moving water

Front 93

Bed Load

Back 93

material, commonly sand and larger, that is transported along the bed of a river.

Front 94

Saltation

Back 94

transport of sediment in which particles are moved in a series of short, intermittent bounces on a bottom surface.

Front 95

Traction

Back 95

the process by which particles roll, slide, or otherwise move on the surface, by such transport agents as streams, wind or waves.

Front 96

Thalweg

Back 96

a line drawn to join the lowest points along the entire length of a stream bed or valley in its downward slope, defining its deepest channel.

Front 97

Levee

Back 97

a long, low ridge of sediment deposited by a stream next to the channel: some levees are built by humans to keep floodwaters from spilling onto a floodplain.

Front 98

River Delta

Back 98

a landform that forms at the mouth of a river, where the river flows into an ocean, sea, estuary, lake, or reservoir. Deltas form from deposition of sediment carried by a river as the flow leaves its mouth

Front 99

What causes water to move in a stream?

Back 99

Gravity.

Front 100

What are the different types of drainage patterns? What causes these differences?

Back 100

Dendritic, Radial, and structurally controlled. Discharge over time/erosion cause these differences.

Front 101

What watershed/drainage basin do you live in? What river does all of the rain in Geneseeo drain into?

Back 101

We are in the Genesee River Basin, and all the Geneseo rain drains into the Genesee River.

Front 102

What is discharge and how do we measure discharge?

Back 102

Discharge is the amount of water flowing through a channel over time. We measure it by multiplying channel width x depth x velocity of water.

Front 103

What causes erosion, transportation, and deposition? What is the difference between erosion and weathering?

Back 103

Weathering happens, then does erosion loosening up sediments that are then carried/transported downstream and eventually deposited.

Front 104

Know how transportation and deposition change with current velocity and sediment size

Back 104

A suspended load results in sediments floating in water.
Soluble Ions are dissolved and carried by moving water.
Saltation is when sand grains roll and bounce along.
Traction refers to when cobbles and boulders roll and slide during high flows.
Bed load is the material moving on the riverbed.

Front 105

suspended load

Back 105

results in sediments floating in water.

Front 106

Soluble Ions

Back 106

are dissolved and carried by moving water.

Front 107

Saltation

Back 107

is when sand grains roll and bounce along.
Traction refers to when cobbles and boulders roll and slide during high flows.

Front 108

Bed load

Back 108

is the material moving on the riverbed.

Front 109

At high velocity,

Back 109

sand and smaller particles are carried in suspension.

Front 110

At moderate velocity,

Back 110

silt and clay remain suspended but sand moves as bed load, and at the lowest possible velocity, sand dropped but silt and clay remained in suspension- all of this summarized in Hjulstrom plot.

Front 111

Understand the difference between laminar and turbulent flow

Back 111

At high velocities, flow becomes chaotic and is turbulent, forming a swirl called an eddy. Viscosity and surface tension act to keep water smooth and slow moving in a laminar flow.

Front 112

How do meanders form?

Back 112

As water erodes in some sections of a straight channel and deposits in other sections, curves called meanders form.

Front 113

What is the thalweg? Where is the thalweg going to be around a meander?

Back 113

The fastest section of the river is the thalweg. Around a meander, the thalweg is the lowest/deepest point of a meander and near the outside bend.

Front 114

What is the difference between a braided stream and a meandering stream?

Back 114

A braided stream is a network of interweaving wide/shallow channels, fluctuating discharge, steep gradient and occur in mountain settings and glacial environments. A meandering stream is very curved and highly sinuous.

Front 115

How do natural levees form?

Back 115

Flooding.

Front 116

How do streams erode? Understand how this leads to terrace development

Back 116

Streams erode from increased discharge and reduced sediment supply. Also, when erosion increases, incision (a river cuts down through its base) happens, leading to terrace development.

Front 117

Know where streams deposit sediment and understand the conditions that lead to this deposition.

Back 117

Climate change and uplift can affect sediment supply and discharge. Streams deposit sediments at a delta when there’s decreased discharge and increased sediment supply.

Front 118

What is a flood?

Back 118

When water overflows channel and spills onto floodplain.

Front 119

What are deltas? What happens at deltas? How do waves and tides change the shape of deltas?

Back 119

The shape of the delta depends on the energy of the system (will be larger if more energy). Deltas are a landform that forms at the mouth of a river, where the river flows into an ocean, sea, estuary, lake, or reservoir. There, sediment is deposited.

Front 120

Sonar

Back 120

using sound waves to determine the distance to reflecting objects, especially depth of the seafloor or a lake bottom

Front 121

What types of features do we see in continental rifts? What about around Mid Ocean Ridges?

Back 121

Divergent boundaries move faults that create a rift zone. Loss of pressure causes decompression melting of the mantle at mid ocean ridges. The hot upper mantle turns to liquid when released forming new oceanic crust.

Front 122

How are oceans explored? How do we make maps of oceans if we have very limited subsurface exploration and direct mapping?

Back 122

Oceans are explored with the use of sonar (measures travel time of sound waves as they bounce off the seafloor), seismic reflection (measure travel time of sound off different layers of rock), sampling floor materials, drilling vessels and submersibles.