Geomorphology Midterm - Horne

Front 1

What is Geomorphology?

Back 1

the scientific study of the morphology of the surface of the Earth and the processes operating on it, in the present, past and future.

Front 2

What is one of the 6 subdivisions of geomorphology?

Back 2

1. Glacial

Front 3

What is one of the 6 subdivisions of geomorphology?

Back 3

2. Fluvial (rivers)

Front 4

What is one of the 6 subdivisions of geomorphology?

Back 4

3. Coastal

Front 5

What is one of the 6 subdivisions of geomorphology?

Back 5

4. Aeolin (wind)

Front 6

What is one of the 6 subdivisions of geomorphology?

Back 6

5. Periglacial (permafrost)

Front 7

What is one of the 6 subdivisions of geomorphology?

Back 7

6. Mass wasting (slope)

Front 8

What is Castastophism?

Back 8

The belief that the earth was shaped by a series of infrequent high magnitude events. Noah's Arc.

Front 9

What was catastrophism created?

Back 9

It was an attempt to explain how the world could have been created in under 10,000 years.

Front 10

What is Uniformitarianism?

Back 10

Belief that the earth was formed by ongoing change over enormous time spans (James Hutton, Theory of the Earth and Sir Charles Lyell)

Front 11

What was the Davisian Cycle of Denudation of land formation?

Back 11

A rapid uplift or rise of land (creating mountains) and a slow wearing down of the mountains until flat again (the flatter the land, the older the area)

Front 12

What was were the 4 stages of dating landscapes according to the Davisian cycle?

Back 12

Uplift, Youth, Maturity and Old age

Front 13

What did Walter Penck (Germany, 1924) argue in regards to land formation?

Back 13

That uplift is continuous and different rates of weathering result in concave, convex and straight slopes

Front 14

What did Lester King ('50s-60s) argue in regards to land formation?

Back 14

Parallel slope retreat: That the top of the mountain will drop debris and begin the raise the ground as the convex point wears down which will eventually level out the ground.

Front 15

What are Etchplains?

Back 15

Emphasis on chemical weathering, particularly in tropical and sub-tropical environments. For example, it rains on a limestone plateau and a stream from the rain etches into the landform creating a channel.

Front 16

What is a Marine Planation by Andrew Ramsey (1846)?

Back 16

large continental plains were created by marine process. Land changed by water/wave erosion.

Front 17

What is Climatic Geomorphology?

Back 17

The emphasis on climate as more influential on land formation rather than rock type. Different climate zones should have different landscapes.

Front 18

What are the problems with climatic geomorphology?

Back 18

Too much emphasis on temp, rainfall and not enough on high-frequency, low-magnitude extreme weather events

Front 19

What are the problems with climatic geomorphology?

Back 19

Concentration on unusual landscapes with extreme environments rather than typical features of the same area

Front 20

What are the problems with climatic geomorphology?

Back 20

Arbitrary boundaries

Front 21

What is the historical approach to geomorphology?

Back 21

Involves trying to identify sequences or stages in landscape development caused by changes in the controlling variables: climate, biological, sea level, tectonic.

Front 22

What is process geomorphology?

Back 22

The dominant form of geomorphology today. Study of mechanics and rates of operation of modern processes and the behaviour of earth's materials. (Strahler, 1950s). Stat analysis of slope and channel morphology

Front 23

What is the difference between the Davisian model and process geomorphology?

Back 23

Davis suggested that change was slow and discouraged field work. Now we know that change occurs fast enough to be measured in short-term measurements and can provide insight into long-term evolution of landscapes.

Front 24

What does process geomorphology put emphasis on?

Back 24

the physical laws that govern movement, specialized measuring and recording equipment designed for particular environments and small scale change since it can't be observed directly.

Front 25

What is the systems approach?

Back 25

Viewed processes and landforms as groups of interrelated components connected by energy flows - functioning as units.

Front 26

What would be an example of the systems approach?

Back 26

drainage basin, a beach, a cave network. All sources of energy combine to create something. Changes in inputs cause changes in outputs and internal form of the system

Front 27

What are the main sources of energy in the systems approach?

Back 27

Climate, gravity and geothermal heat

Front 28

What would be an example of the systems approach?

Back 28

An increase in storminess, wave intensity (input) changes the gradient, sediment size and other characteristics of a beach (internal form) and the amount of sand deposited on the beach (output)

Front 29

Seven types of chemical weathering

Back 29

1) Hydroloysis : the dominant type of weathering process in igneous rocks. Causes decomposition of silicates. eg...Feldspar

Front 30

Seven Types of chemical weathering

Back 30

2) Cation exchange: Substitution of hydrogen ions. Minerals that solidify at higher temperatures are more unstable than those solidifying at cooler ones

Front 31

Seven types of chemical weathering

Back 31

Oxidation: Reaction between oxygen and substance causing redish brown stains.Iron.

Front 32

Seven types of chemical weathering

Back 32

Reduction: The opposite process of oxidation

Front 33

Seven types of chemical weathering

Back 33

Carbonation: Reaction between minerals and carbonate ions

Front 34

Seven types of weathering

Back 34

Hydration: Water being helped by mineral structure. Formation of clays.

Front 35

Seven types of weathering

Back 35

Solution: The complete dispersal of mineral ions in water. Gypsum

Front 36

Unconsolidated material

Back 36

Most of the earths surface is covered by this loose material of rock and soils. the by products of may types of erosion

Front 37

Factors that cause uncosonlidated material.

Back 37

Climate, Biological weathering, bacteria, plants,rocks.

Front 38

Sedimentary rocks

Back 38

Derived from pre-existing rock or plant and animal remains formed at or near the surface but hardened or consolidated by dewatering, compaction and cementaion.

Front 39

Metamorphic rocks

Back 39

Thermal, dynamic and geochemical process that cause solid rock to recrystalize without entering on igneous or liquid state

Front 40

Metamorphic rock examples

Back 40

Weak: limestone into marble, mudstone or shale into slate.

Moderate: Quartz into quarzite

Intense: Granite into gneiss

Front 41

Rock structure

Back 41

Folds, Joints, Faults,

Front 42

Sediments

Back 42

Unconsolidated material that has been transported and deposited

Front 43

Feedback loops

Back 43

eg: beaches are in constant change because they are never in perfect equilibrium with changing forces

Front 44

Static equillibrium

Back 44

Unchanged landforms over a short steady time interval

Front 45

Dynamic equillibrium

Back 45

Progressive change over long periods of time

Front 46

Cascading systems

Back 46

When the output of one system becomes the input of another system

Front 47

The problem of scale

Back 47

Short time span forces on small areas are different from long time span forces on large areas. Therefore, no standard scales for geomorphology research

Front 48

Neocatastrophism/neohistoricism

Back 48

Low frequency high intensity events are cumulatively more important than high frequency low intensity events, but not related to biblical restrictions.

Front 49

New technologies

Back 49

GIS, GPS, Digital elevation models, Remote sensing.

Front 50

Porosity

Back 50

Proportion of the volume containing spaces

Front 51

Characteristics of water

Back 51

Have electric charges that attract one another. This give it surface tension.

Front 52

Specific Yeild

Back 52

The amount of water that can drain away under gravity to total volume of substance

Front 53

Permeability

Back 53

The ability and rate at which water passes through a substance

Front 54

Stress

Back 54

An applied force or system of forces that tends to strain or deform a body

Front 55

Types of stress

Back 55

1-Confining: Equal in all directions.

2-Compressional: Pushed together shortening the object.

3-Tensional: Tending to stretch or pull objects apart.

4-Shear: Acts parallel to a surface and causes one object to slide over another or changes the angles of an object.

Front 56

Tree rings

Back 56

Can be used to date objects up to 4000 years old

Front 57

Carbon-14

Back 57

Has a half life of 5730 years

Front 58

Cosmic Isotopes

Back 58

Used to date bones and carbonate fossils

Front 59

JD Hack Dynamic Equilibrium

Back 59

Landscape elements rapidly adjust to the processes operating on them and to the materials they consist of

Front 60

What is an equilibrium

Back 60

A balance between force and resistance which can persist despite disturbances

Front 61

What is a positive feedback loop?

Back 61

Self perpetuating change that reinforces or increases the effect of the original change

Front 62

What is a negative feedback loop?

Back 62

Compensates for or counteracts the original change.

Front 63

Example of a positive feedback loop

Back 63

Increased snow cover increases albedo resulting in colder temps and more snow

Front 64

Example of a negative feedback loop

Back 64

A sandy beach counter increased wave energy reducing its gradient

Front 65

How do equilibriums effect landforms?

Back 65

If something remains in equilibrium, it remains unchanged

Front 66

What is dynamic metastable equilibrium?

Back 66

When there is a sudden extent of energy that exceeds the threshold of resistance changes can be irreversable. eg Global warming melting the permafrost melts and may not reform even if temp cools

Front 67

What is a cascading system?

Back 67

When the output of one system becomes the input of another system (rain - surface water, soil water, ground water - stream)

Front 68

Unstable systems

Back 68

Positive feedback loops are unstable because they tend to grow and change

Front 69

Non-equilibruim and disequilibrium

Back 69

Do not tend toward stable end state. Have not reached stable end state

Front 70

Ergodic Hypothesis and space-time substitution

Back 70

Used to look at the development of a landform over a large area and assume that the differences (over space) represent stages in development (over time) at any one place

Front 71

Theory of Equifinality

Back 71

Similar landforms can evolve in different ways therefore, morphology of a landform cannot be used to identify the mode of origin (mechanical and chemical weathering can lead to the same end result) - opposite is also true similar processes lead to different results.

Front 72

What does the Theory of Equifinality say about science's multiple working hypotheses?

Back 72

That no hypothesis can be proven.

Front 73

Geomorphology today

Back 73

it is now accepted that landscapes are a combination of of both high and low frequency events.

Front 74

What are the 3 Geomorphic processes?

Back 74

1. Weathering: wearing away of material

Front 75

What are the 3 Geomorphic processes?

Back 75

Transportation: moving material

Front 76

What are the 3 Geomorphic processes?

Back 76

Deposition: moved material comes to rest

Front 77

There is constant change but rate of change depends on what?

Back 77

Energy available (resistance of material and length of time)

Front 78

When did the Nile River begin?

Back 78

5,000 yrs ago

Front 79

When did Korea begin to keep records on their climate?

Back 79

1392-1863

Front 80

What are some other problems with understanding geomorphology?

Back 80

We cannot assume the same process occurred at the same rate in the past as the present due to climate change

Front 81

What are some other problems with understanding geomorphology?

Back 81

Low intensity events occur frequently

Front 82

What are some other problems with understanding geomorphology?

Back 82

High intensity events occurs infrequently

Front 83

What are some other problems with understanding geomorphology?

Back 83

Most change is result of moderate conditions

Front 84

What are some other problems with understanding geomorphology?

Back 84

Theory of eqifinality, different processes can create the same result

Front 85

How long is long?

Back 85

Depends on the scale

Front 86

What are the sources of energy?

Back 86

Solar - due to climate, geothermal heat - solar radiation is highest where magma is closest to the surface, gravity - constant

Front 87

How much effect does biogeomorphology have on the landscape?

Back 87

It is at least equal to that of abiotic geochemical and geophysical (gravity and uplift) activities

Front 88

What effect does biogeomorphology have?

Back 88

Roots alter texture, structure, cohesion and chemical properties of earth materials

Front 89

What effect does biogeomorphology have?

Back 89

Parts of plants above ground alter flow of water and wind

Front 90

What effect does biogeomorphology have?

Back 90

vegetation promotes stability, soil development and formation of specific landscape features

Front 91

Examples of vegetation specific landforms are:

Back 91

Meandering rivers with oxbow lakes. Rounded hilltops, coastal salt marshes, mangrove swamps

Front 92

How does the carbon cycle influence geomorophological processes?

Back 92

Through the biosphere (plants and animals), the lithosphere (limestone and fossil fuels) dissolved in water and as the gas CO2

Front 93

Evolutionary geomorphology

Back 93

The presence or absence of particular species leads to significant landscape stability or change. EG beaver controls its environment to maximize survival by building a dam

Front 94

The amount of carbon on the planet is constant, just changes location between lithoshphere, hydrosphere, biosphere and atmosphere over time

Back 94

Most carbon bonds to other elements to form compounds such as calcuim carbonate (limestaon, hydrocarbons (coal, oil) and carbon dioxide

Front 95

How does the carbon cycle work?

Back 95

animals return CO2 to the atmosphere through respiration and plants absorb it out of the atmosphere through photosyntesis. Over long periods of time, dead plants and animals are buried and compressed into fossil fuels. When they are burned CO2 is added back into the atmosphere

Front 96

What non human ways is carbon added back into the atmosphere?

Back 96

volcanic eruptions which can dissolve in water as carbonic acid which is a major actor in chemical weathering. Sea creatures with calcium carbonate shells also use it. When they die they form limestone and weathering of limestone adds CO2

Front 97

What are P and S waves?

Back 97

They are Primary and Secondary waves that come from earthquakes. They travel through the earth.

Front 98

Where do P and S waves travel?

Back 98

Through solids, liquids and gases whereas S waves only travel through solids.

Front 99

How do earthquakes allow scientists to understand the composition of the earth?

Back 99

They use seismographs

Front 100

What are the layers of the earth?

Back 100

Core, Mesolayer, Mantle, crust

Front 101

What is the core/ mesolayer made of?

Back 101

iron/nickel compound solid in the centre but molten (liquid) on outside

Front 102

What is the mantle made of?

Back 102

Mostly silica and oxygen lower mantel solid but slow steady movement in upper mantle

Front 103

What is the crust?

Back 103

A thin layer on the surface, mostly made of silicates and aluminum. Ocean crusts are silicate and magnesium

Front 104

What are plate tectonics?

Back 104

a series of plates that move due to the moving mantle beneath. There are 7 large place and several smaller ones

Front 105

How much do the continents move each year?

Back 105

5-10cm

Front 106

What is orogenesis?

Back 106

When plates are moving towards each other then compression forces cause mountain building

Front 107

What is folding?

Back 107

When the plates are moving toward each other and cause the land to be folded up like a hill

Front 108

What is faulting

Back 108

When the plates are moving toward each other and one side is pushed up while the other is pulled down or stays in the same place

Front 109

What are divergent plates?

Back 109

When plates are moving away from each other then magma rises to the surface forming mid-ocean ridges

Front 110

What is subduction?

Back 110

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

Front 111

What is a transform Fault?

Back 111

Two plates slide past each other in opposite directions. Most on ocean floor except San Andreas fault in California is on land

Front 112

As mountains wear down material is transported to lower levels which may be:

Back 112

Places of inactivity (Atlantic coast of Canada)

Places of subduction (Pacific coast of Canada)

Places of collision (mountainous areas)

Front 113

What happens when areas that have been glaciated melt? And what happens when the ocean's water increases?

Back 113

The surface springs back (Hudson Bay cm/yr)

The ocean floor is pushed down

Front 114

What are the 3 situations in which volcanoes occur?

Back 114

1. In curved arcs corresponding to subduction zones

Front 115

What are the 3 situations in which volcanoes occur?

Back 115

2. Straight volcanic chains within post-tectonic fold mountains

Front 116

What are the 3 situations in which volcanoes occur?

Back 116

3. Extinct volcanoes formed as plates moved over mantle plumes "hot spots" near mid-ocean ridges (Iceland, Azores)

Front 117

What are the types of volcanoes?

Back 117

Lava platforms or plains: formed when basic magma forms a liquid lava that flows downhill. the surface hardens and is broken up by still molten material below creating a rough surface. Often stepped reflecting a series of flows

Front 118

What are the types of volcanoes?

Back 118

Shield Volcanoes (basalt rocks): mountain shapes, gently sloping sides. Mauna Loa, largest rises more than 9,000m from ocean floor. Erupts very fluid lava which follows fissures and vents down the volcano. The silica content controls fluidiy - less than 50%

Front 119

What are the types of volcanoes?

Back 119

Cinder cones: layers of ash create steeper slopes.

Front 120

What are the types of volcanoes?

Back 120

Stratovolcanoes - composite: Cone shaped. Explosive eruptions. Lava not as fluid, more localized distribution. Pyroclastic flows (hot dense cloud of volcanic gas, rock, ash and water) - Pompeii, Montserrat

Front 121

What are Lahars?

Back 121

Mudflows, water from crater lake, rainfall, melting snow and ice mixes with ash and flows down slope. Thick flood of wet concrete rather than water. Solidifies when settles

Front 122

What cause the greatest number of volcanic deaths?

Back 122

Lahars and pyroclastic flows

Front 123

What are Calderas?

Back 123

Steep sided circular depressions larger than original volcanic vents. Typically 5-14km in diameter. Created when the cone collapses because the magma below has been removed.

Front 124

What is the rock cycle (James Hutton)?

Back 124

Begin as magma in earth's crust or lava flows, uplifts expose as igneous rock. Weathering and transportation carry material to ocean where they are compressed and cemented together into sedimentary rocks. Uplifting allows process to repeat.

Front 125

What are the 3 rock types and how are they formed?

Back 125

Igneous: Crystalline, from magma (Intrusive: granite, gabbro, Extrusive: basalt, pumice, obsidian). Type depends on chemical makeup, speed of cooling, re-cooling, crystallization, neighbouring rock during formation.

Front 126

What are the 3 rock types and how are they formed?

Back 126

Metamorphic: Thermal, dynamic and geochemical processes cause solid rock to recrystallize without entering an igneous or liquid state. Both sed and ig can be metamorphosed by heat changing their mineral composition and structure

Front 127

What are the 3 rock types and how are they formed?

Back 127

Sedimentary: sediment derived from pre-existing rocks or from plant and animal remains formed at or near the surface but hardened or consolidated by dewatering, compaction, cementation. Most from igneous (Quarts most common, mica, calcite, feldspar, clays)

Front 128

How are igneous rocks classified?

Back 128

Grain size, tecture. Feldspar content (alkali/calcic) Quartz content (acid or base). Amount of ferromagnesian content.

Front 129

What are intrusive rocks?

Back 129

Formed below the surface. Could be either:

Less resistant then surrounding rock to erosion (form a ridge) or more resistant (form a valley)

Front 130

What is a sill formation?

Back 130

A horizontal formation in rock

Front 131

What is a dike formation?

Back 131

A vertical formation in rock

Front 132

What are the two types of sedimentary rocks?

Back 132

Clastic: from broken rocks that have been eroded, transported and deposited in layers or beds parallel to surface of deposition

Non-clastic: carried in solution and precipitated by chemical or biochemical processes. Paricularly carbonates formed by coral and other organisms in warm, clear, shallow marine environments.

Front 133

How are sedimentary rocks classified?

Back 133

grain size from rudites (rounded, transported conglomerates, angular) to sandstones and mudstones and by mineral composition. Also by bedding create alternating layers of limestone and mudstone

Front 134

How do sedimentary rocks look?

Back 134

Most have horizontal lines or slightly sloping distorted by later earth movements

Front 135

What are examples of weak, moderate and intense metamorphic rocks?

Back 135

Weak: limestone into marble. Mudstone or shale into slate

Moderate: quartz into quartzite

Intense: Granite into gneiss

Front 136

What are some key things about rock structure?

Back 136

Folds in rocks can be any size but over time erosion will wear down in high places and fill in low places in the folds.

Front 137

What are some key things about rock structure?

Back 137

Joints: a fracture that opens up without any movement of rock on either side

Front 138

What are some key things about rock structure?

Back 138

Fault is a fracture where the location of one side has moved in relation to the other side (horizontal or vertical). Points of cleavage are subject to weathering

Front 139

What are some key things about rock structure?

Back 139

A typical formation is called Graben and horst (Graben - low part of fault, Horst - high part of fault). - Gravenhurst

Front 140

What is the most important identifier for Sedimentary rocks?

Back 140

Grain size. Depends on characteristics of source area and by the sedimentation process. Calipers or Wentworth Scale or phi scale are used (REVIEW PAGE 53)

Front 141

What does measuring density identify?

Back 141

The type of minerals in the rock

Front 142

How is porosity created?

Back 142

If grains are same size there may be large pockets of space (40%). If they are different sizes the small grains will settle between bigger grains and reduce porosity.

Front 143

How does speed of deposition affect density?

Back 143

The slower, the more dense.

Front 144

How does the method of deposition affect density?

Back 144

Waves create more dense pack than settling in still water

Front 145

What are key factors in sedimentation?

Back 145

Sediment tends to sort by shape, size and density. Velocity, turbulence, and depth of water are also factors.

Front 146

What are key factors in sedimentation?

Back 146

Grains become finer as they are transported. One size may flow faster than another size. Mixing grains changes the results

Front 147

How do you calculate porosity?

Back 147

Volume of void space/total volume X 100

Front 148

What affects porosity?

Back 148

Unconsolidated material, grain size, sorting shape and packing. Space can be reduced by compaction or the filling of voids by cementing material

Front 149

What do Hydrologists avoid regarding porosity?

Back 149

Anything that doesn't allow the movement of water. Space that are too small for fluid flow, large spaces connected by small throats, dead ends or unconnected voids.

Front 150

Why does water coat a surface with a fine film?

Back 150

Waters surface tension because water molecules have electric charges that make them attract to each other and other charged materials.

Front 151

What is specific yield?

Back 151

Amount of water that can drain away under gravity to total volume of substance. The smaller the grain size, the greater the surface area producing lower specific yields (course gravel - highest. Clay - lowest)

Front 152

What is permeability?

Back 152

ability to allow liquids to pass through. Clay has high porosity but small unconnected voids so low permeability. Water attached to sides of clay reduces the side of voices so water can't flow through. Sand has lower porosity but larger and better connected voids for more permeability.

Front 153

How is stress measured?

Back 153

force per unit area

Front 154

What is strain?

Back 154

Response of rock to stress - deformation campared to original size and shape. Elastic deformation: changes shape but will return to original shape after stress is removed

Front 155

Strength

Back 155

Compressive Strength: capacity to withstand compression before break or crushed

Tensile Strength: resistance to force trying to tear it apart.

Rock may be resistant to mechanical weathering from waves but vulnerable to chemical weathering from salt in water

Front 156

How does dating by Radioactive isotopes work?

Back 156

Radioactive isotopes decay at a set rate (1/2 life after 1 unit of time, etc.). By measuring the ratio of the 2 isotopes the age of the rock can be determined.

Front 157

How does carbon dating work?

Back 157

Carbon-14 has a 1/2 life of 5730yrs. Ratio of C-14:C-12 in anything living is the same as ratio in atmosphere. Once dead it stops collecting C14. The ratio of 14C:12C reflects how long ago dead. If 1/2 life is known then the time since death can be calculated. Only until 50,000yrs

Front 158

What are problems with carbon dating?

Back 158

inaccruate by 500-5000yrs bc it assumes no changes in earth's magnetic fields.

Front 159

What are cosmic Isotopes?

Back 159

Cosmic rays that interact with atoms in the atmosphere producing radioactive nuclides of Helium, Neon, Beryllium, Carbon, Aluminum, chlorine which build up on rack surfaces so length of time exposed can be calculated. Dates bones and carbonate fossils.

Front 160

How is lichen used to determine age?

Back 160

Diameter on rocks determines length of exposure on retreating glaciers (up to 1000 yrs)

Front 161

How does earth record it's magnetic field?

Back 161

By iron and other magnetic rocks as they were formed.