Geology 101: Final

Front 1

What's the largest accessible soure of freshwater?

Back 1

Groundwater

Front 2

unsaturated zone

Back 2

air and water in pores

Front 3

saturated zone

Back 3

water only in pores, water table separates it from the unsaturated zone, mimicing topography

Front 4

How does groundwater flow through rock? (2)

Back 4

porosity (% pore space in rock / pore size) & permeability (capability of a substance to allow the passage of water / how pore space is connected)

Front 5

aquifer

Back 5

high enough permeability to produce useable amounts of waters (sand, sandstone, some limestones, some basalt, conglomerate)

Front 6

aquitard

Back 6

doesn't conduct water in useable amounts (clay, shale, crystalline bedrock)

Front 7

Confined vs. unconfined aquifer

Back 7

confined aquifer is below of sandwiched between aquitards

Front 8

potentiometric surface

Back 8

elevation that water within a confined quifer will rise to due to confining pressure

Front 9

flowing artesian well

Back 9

water flows from well without pumping

Front 10

recharge area

Back 10

place where surface water infiltrates aquifer

Front 11

discharge area

Back 11

place where GW flows back up to surface

Front 12

hydraulic head

Back 12

the potential energy available to drive the flow of a given volume of GW at a location,

Front 13

hydraulic gradient

Back 13

calculated by taking the difference of the two heights and dividing it by the distance between them. (h1-h2/j)

Front 14

Different issues that arise from wells

Back 14

lowering water table, subsidence (collapsing of land), sline intrusion, flow reversal (septic groundwater begins to flow towards well)

Front 15

Karst landscapes

Back 15

distinctive type of landscape that develops due to chemical weathering of limestone (you need limestone bedrock and abundant groundwater)

Front 16

What's the chemical reaction that results in the formation of caves?

Back 16

1. CO2 and H2O make carbonic acid (H2CO3). Then, that and calcite (CaCO3) react and dissolve one another (Ca^2+ and 2HCO3-)

Front 17

Stalagmites

Back 17

floors, calcite or aragonite based

Front 18

Stalagtites

Back 18

hang tightly from the roof

Front 19

Three common features in Karst landscapes

Back 19

1. Sinkholes (cavern collapse), 2. Natural Bridges, 3. Disappearing stream (goes into cave system)

Front 20

Two ways hot springs are formed

Back 20

1. deep GW heated at depth and returns to surface, 2. GW heated near surface by magma / hot rock produced by recent volcanism (geothermal regions)

Front 21

Geysers

Back 21

water is superheated above boiling point, rises to surface and expands to steam at the pressure decreases. All water becomes steam and erupts.

Front 22

Two reasons why we care about streams

Back 22

1. source of water for communities, 2. major agent of change on Earth's surface

Front 23

Run-off

Back 23

Sometimes what streams are referred to. Runoff = precipitation - evapotranspiration

Front 24

Four types of drainage networks (4)

Back 24

Dendritic (delta), Radial (volcano), Rectangular (fractures), Trellis (Resistant ridges)

Front 25

How do basins work?

Back 25

They're separated by divides, creating different drainage basins.

Front 26

Stream Flow / Discharge measurement:

Back 26

Q = Velocity x Area (Width x Depth)

Front 27

Does velocity vary in different points?

Back 27

Yes, the shape of the channel affects it.

Front 28

Explain what a curved channel looks like.

Back 28

The outside bank is the deepest and is getting eroded significantly faster. The inner bank experiencing a deposition of the point bar. This is due to the Thalweg or spinning current.

Front 29

Erosion

Back 29

most occures closer to headwaters

Front 30

Deposition

Back 30

most occurs further along profile (nearer mouth), needs to be transported from the headwaters

Front 31

Three types of stream loads

Back 31

1. Dissolved Load (ions carried in the water column), 2. Suspended Load (clay entrainment carried in the water column), 3. Bed Load (sand and pebble saltation, all movement along the stream bottom / bed)

Front 32

What is the gradient, energy, and rock type at the Headwaters vs Mouth?

Back 32

Headwaters: high gradient, high energy (turbulent flow), and coarse gravel. Base Level: No gradient, lowest energy (laminar flow), and clay sized sediment

Front 33

Logitudinal profile

Back 33

Over time, streams erode or deposition to reach this equilibrium profile.

Front 34

Base level

Back 34

lowest elevation to which a stream can erode to (globally = sea level, locally = lakes, ponds, dams, resistent rock, etc.)

Front 35

Headward erosion

Back 35

Knickpoint (where the rock ledge defines the local base level) moves towards head of stream

Front 36

What happens if the base level of a stream goes up or down?

Back 36

Up: increased deposition, Down: increased erosion

Front 37

What if land rides and base level remains the same?

Back 37

Increased erosion, straight downcutting (grand canyon)

Front 38

Types of Streams (2)

Back 38

Braided (high sediment load during floods, choking the channel during normal flow), Meandering (gentle gradient, mature, high volume because of increased length)

Front 39

Oxbow Lake

Back 39

Created from a meander.

Front 40

Point bar

Back 40

On the inner neck of a meadering stream, creates a natural levee at the end

Front 41

Delta

Back 41

fan of distributary streams at the mouth of a stream. Form when current slows as running water meets standing water. Stream drops sediment load.

Front 42

What's urbanization causing with surface water concerns?

Back 42

Pollution, damming, and overuse.

Front 43

Why is urbanization a problem?

Back 43

Less lag time between rain event and peak discharge, higher peak discharge (maybe over floodstage)

Front 44

What does a beach drift develop? (3)

Back 44

spits, baymouth bars, and barrier islands

Front 45

Spits

Back 45

develop where longshore drifts extend beach into bars (where estuaries / tributaries of river systems meet the ocean). They usually have a curl at the end

Front 46

Baymouth bar

Back 46

if the spit crosses the entire bay opening, it is called a baymouth bar. It creates a barrier between the bay and ocean and causes sedient load from the river to fill in the bay.

Front 47

Barrier Islands

Back 47

have the characteristic curl on the downcurrent end of the island

Front 48

What do storm waves do to sand?

Back 48

Take it offshore and flatten / widen beaches

Front 49

Are inlets important in sand bars?

Back 49

Yes, because they're important for transportation and storage of sand

Front 50

What happens to barrier islands is the sea level rises?

Back 50

They migrate landward

Front 51

Some evidence of barrier island migration

Back 51

oyster shells, salt marsh muds

Front 52

Hard stabilization (3 types)

Back 52

used to stop beach drift, but causes problems and contributes to beach erosion. Groins (uneven displacement of sand), Jetty (creates a sandbar), Breakwater / Seawalls (extends the beach)

Front 53

Estuaries

Back 53

Flooded river valleys, such as the Chesapeake and Delaware Bays. Site involves mixing of saline and freshwater systems.

Front 54

Why are estuaries important?

Back 54

Ecologically: natural nurseries for fish, house migratory birds. Natural filter of river water, commercial / recreational use (?)

Front 55

Ocean waves (explain four qualities)

Back 55

Crest (up wave), Trough (down wave), wavelength, and wave height

Front 56

Wave orbitals

Back 56

circular wave motions that overlap one another. Usually go as deep as the wave length / 2.

Front 57

What happens when the wave depth > water depth?

Back 57

Becomes waves approaching the shore. The height begins to increase while the length decreases, becoming more intermittent.

Front 58

Explain zones and sand as the wave approaches land

Front 59

Wave refraction

Back 59

waves "feel" the bottom and slow down as a result. Creates curved waves (resulting in the convergence of the bottom and wave crests)

Front 60

What % of global water is saline water?

Back 60

97%

Front 61

What's ocean water's composition?

Back 61

water, salt (3.5%) (chloride, sodium, dulfate, MG, Ca, K)

Front 62

Where do the ions for salt come from?

Back 62

Chemical weathering, transport of dissolved load in rivers, volcanic gases

Front 63

Salinity

Back 63

lower % at high latitudes, 35.5% at equator, and >36% at tropics. Evens out at just under 35% at about 4,000m

Front 64

Surface currents

Back 64

driven by wind at surfance (upper 400 m), usually warmer

Front 65

Deep water currents

Back 65

Driven by difference in temperature and salinity (density), usually cold

Front 66

Coriolis Effect

Back 66

Surface waves experience a variation with depth, as the Earth rotates

Front 67

Deep currents: upwelling

Back 67

There's an upwelling, causing the Ekman transport and Pycnocline to go away from the shore

Front 68

Deep currents: downwelling

Back 68

There's a downwelling, causing the Ekman transport / Pycnocline to get sucked towards the shower,

Front 69

Ocean-climate connection

Back 69

1. Currents heat or cool overlying air. Cold = cold, warm = warm. 2. They redistribute heat (horizontally by surface currents from topics to poles, vertically by deep currents). Changes in this redistribution can lead to ice ages. 3. They store heat (higher heat capacity than air, top 10 ft holds as much heat as atmosphere). 4. Ocanes store CO2 (about 50% total CO2 added to atm by humans in the last centure was absorbed by oceans)

Front 70

Normal vs. El Nino pattern

Back 70

Normal = cool water in E. Pacific, warm in W. Pacific; El Nino = warm water in equatorial Pacific, creating a deeper thermocline at the site of the former upwelling, and reversing the shallow water current

Front 71

What is a glacier?

Back 71

thick ice mass, originates on land, and resulted from the accumulation, compaction, and recrystallization of snow

Front 72

Glacial ice over time

Back 72

As you get deeper, the ice gets denser, with the deepest ice being 2,000m deep, 130,000 years old, and < 20% air.

Front 73

Two dominant glacial types

Back 73

Alpine (valley, usually found in mountain ranges, lengths greater than width), and Continental (ice sheets, usually much larger covering 10% of Earth's land, sometimes cause depressions)

Front 74

Glacial movement is driven by…

Back 74

gravity, as it is usually downhil. It tends to be faster in the middle and slower on the sides and bottom, due to friction of ice with rock.

Front 75

Crevasses occur in the ____ zone

Back 75

Brittle zone. This zone is usually 50-60 meters deep, then resulting in the plastic zone, which has more ductile movement.

Front 76

Basal slip

Back 76

the amount the ice has moved on the very bottom

Front 77

Shearing and flow

Back 77

the motion within the plastic zone, results in curved flow within glacials

Front 78

Glacier ice budgeting (two zones)

Back 78

1. Zone of Accumulation: grows with precipitation (in the form of ice and snow). The snow line separates it from the 2. Zone of Ablation

Front 79

What are some processes that contibue to the loss of ice in the Zone of Ablation?

Back 79

Sublimation (evaporation), calving (breaking off), melting (either at toe or into surface pools), or meltwater streams

Front 80

Glacial Dynamics (two processe)

Back 80

They can either advance or retreat. Regardless, they always more downslope.

Front 81

Glacial erosional processes (2)

Back 81

Plucking (lossen and lift blocks of rock), Abrasion (grinds rock into "rock flour", giving bodies of water awesome color and leaving glacial striations)

Front 82

Alpine Glacier landscape

Back 82

tend to accentuate the landscape, see picture

Front 83

Continential Glacier landscape

Back 83

a lot more surpressed

Front 84

Cirque (Alpine)

Back 84

bowl shaped, the head of the valley glacier / the source. When the ice is gone, they typically create mountain lakes called tarns

Front 85

Arete (Alpine)

Back 85

Knife-shaped ridge between 2 glacial valleys

Front 86

Horn (Alpine)

Back 86

Pyramid-like peak, from 3 or more cirques surrounding a mountain summit

Front 87

Where does most of the glacial sediment get deposited?

Back 87

most is deposited in the end moraine, a pile of debris at the terminus of the glacier. These sediments are unsorted (so big mix of sizes) and are known as till.

Front 88

Glacial Deposits (2)

Back 88

1. Till (unsorted, deposited by the glacier), 2. Sorted sediments (material laid down by glacial meltwater, outwash)

Front 89

Lateral vs. Medial moraines

Back 89

lateral moraines meet up at the tip of an arete, forming a medial moraine. The number of medial moraines is one less than the # of tributary glaciers.

Front 90

Terminal Moraine

Back 90

the final moraine in front of the glacier. Marks furthest extent of glacial advance.

Front 91

Ground Moraine

Back 91

the debris accumulated under the glacier

Front 92

Kettle Lake

Back 92

formed from ice blocks left behind by retreating ice

Front 93

Drumlins

Back 93

streamlined hills that have a steep side and shallow-sloping side (the steep sides face the direction of retreat)

Front 94

Eskers

Back 94

sinuous deposits associated with meltwater streams

Front 95

Erratics

Back 95

large boulders that are lithogically very different from the surrounding bedrock

Front 96

Glaciations

Back 96

time periods when glaciers grow and cover extensive contential areas (Ice ages), interglacials are the time between glaciations

Front 97

How many ice ages have occurred in Earth's history?

Back 97

5, we're currently the cooler than average period

Front 98

Pleistocene glaciation extent

Back 98

went into north america, where much of the deposition occurred (including the Wisconsinan and Illinoian glaciation). Scouring and erosion occurred mostly in canada.

Front 99

Pleistocene glaciation environments

Back 99

Tundras surrounded the glacier, then cold-weather conifer forect, temperate-weather deciduous forests, and finally cypress in the lower part of florida

Front 100

Is glacial retreat normal?

Back 100

Since we're in an interglacial, it is expected. However, our retreat increased rapidly in the mid 1900s.

Front 101

How do ice cores work?

Back 101

They measure two isotopes of Oxygen. O16 evaporates easier, which means that when the global temps are cooler, O16 is more likely to evaporate and rain at the poles, causing more O16 in the ice cores. The warmer it gets, the more O18 there will be.

Front 102

Younger Dryas

Back 102

cooling events caused by shut-down of thermohaline circulation in North Atlantic. Normally, the warm surface currents bring water with high salinity to N.Atlantic. The heat is then transferred to atmosphere and the salty water sinks (downwelling). This doesn't happen during the younger drya. The meltwater of retreating glaciers adds freshwater to N. Atlantic and there's no heat transfer.

Front 103

Absolute temperatures

Back 103

Atmospheric and Sea Surface temperatures. These affect sea levels and distribution of climate belts. They're affected by greenhouse gases

Front 104

CO2 and long-term climate change (4)

Back 104

1. Volcanic Activity (increases), 2. Tetonic Uplift (decreases because of increased chemical weathering), 3. formation of organic-rich deposits (decreases CO2), 4. evolution of life (decreased CO2)

Front 105

What is CO2 absorbed by?

Back 105

Dissolution in oceans, chemial weathering, and plant metabolism

Front 106

CH4 (methane) is released because of…

Back 106

landfills, gas systems, cattle farts, coal mining, rice paddies, and permafrost melting.