GEOG 272

Question 1

Uniformitarianism vs Catastrophism

Answer 1

Uni: A principle that states that geologic processes that occurred in the past can be
explained by current geologic processes
Catastrophism: A principle that states that geologic processes occur suddenly

Question 2

What is the Geographic cycle?

Answer 2

A theory of the evolution of landforms stating a progressive
cycle of erosion, stages are sequential and non reversible and is driven by climate

Question 3

What are the 5 factors of landscape evolution?

Answer 3

Climate, tectonics, topography, geology, biology

Question 4

How does climate impact landscape evolution?

Answer 4

Influences geomorphic processes
and landscape evolution
● Directly through amount,
intensity, and type of
precipitation
● Indirectly through
vegetation

Question 5

How does topography influence landscape evolution?

Answer 5

Drives the speed and spatial pattern of geomorphic processes

Provides the potential energy that fuels gravity-driven erosion

Question 6

How does biology influence landscape evolution?

Answer 6

Vegetation affects hydrologic processes, erosion potential, and sediment yields
Animals influence geomorphology (e.g., beavers building dams)
Human influence on geomorphic processes

Question 7

How does geology impact landscape evolution?

Answer 7

Physical properties of material and structure influence erosional resistance

Question 8

How do tectonics impact landscape evolution?

Answer 8

Uplift supplies mass to geomorphic systems: plate motions, tectonic
settings

Question 9

What is the general systems theory?

Answer 9

A framework for understanding how different parts of a system interact and influence each other.

Question 10

What are landscape in geomorphology?

Answer 10

Landscapes are seen as systems where inputs (like energy and
sediment) and processes (like erosion and deposition) interact to create outputs (like
landforms).
○ Feedback loops (positive or negative) regulate these interactions and drive
landscape evolution.

Question 11

What are endogenic processes

Answer 11

Plate tectonics and structural processes

Question 12

What are exogenic processes?

Answer 12

Weathering, Erosion, Transport and Deposition

Question 13

What are the 3 types of systems and their description

Answer 13

Morphological system: a system where we understand the relationships between elements and
their attributes in a vague sense based only on measured features or
correlations. In other words, we understand the form or morphology
of a feature, as a system based on the connections between its
elements.

Cascading system: a system where we are primarily interested in the flow of energy
and/or matter from one element to another and understand the
processes causing this movement. In a cascading system, we do not fully understand quantitative relationships that exist between elements
related to the transfer of energy and/or matter.

Process-response system: a system that integrates characteristics of both morphological and cascading systems. In a process-response system, we can model the processes involved in the movement, storage, and transformation of
energy and/or matter between system elements and we fully
understand the form of the system in terms of measured features and
correlations

Control system: a system that can be intelligently manipulated by the action of
humans

Question 14

What are the 5 principles of process geomorphology?

Answer 14

1. A delicate balance or equilibrium exists between landforms and processes. The character of this balance is revealed by considering both factors as systems or as parts of a system (equilibrium)
2. The perceived balance between process and form is created by the interaction of
   energy, force and resistance
3. Changes in driving force and/or resisting framework may stress a system beyond its
   defined limits of stability. When these thresholds (limits of equilibrium) are
   exceeded, the system is temporarily in disequilibrium and a major response may occur
4. Various processes are linked in such a way that the effect of one may initiate the action of another (feedback)
5. Geomorphic analysis can be made over a variety of time intervals. In process studies
   the time framework utilized has a direct bearing on what conclusions can be made
   about process and form (time)

Question 15

What are the types of equilibrium?

Answer 15

Static: short timescale –> No change
Steady state: years to decades –> Change occurs, but average conditions are maintained
Dynamic: centuries –> Change occurs: fluctuations in conditions are not offsetting
Dynamic metastable: long timescale + events –> Change occurs, fluctuations in conditions are offsetting

Question 16

What is the dynamic equilibrium concept?

Answer 16

a landscape rapidly adjusts to the processes
acting on the geology and thus process and form reveal a “cause and effect” relationship that forms within a landscape and maintains their character - as long as the fundamental controls do not change!

Question 17

Difference between exogenic and endogenic energy?

Answer 17

Exogenic energy drives most weathering and erosion systems that wear down the Earth’s surface (planation)

Endogenic energy derived from decay of radioactive minerals and residual primordial heat drives mountain building and plate tectonics - uplift

Question 18

What are the energies driving Earth’s key systems?

Answer 18

■ Rotational Energy of Solar System
■ Solar Radiation
■ Gravitational Attraction
■ Plate Movement
■ Geothermal Heat Flow

Question 19

In process geomorphology, landforms represent what?

Answer 19

the interaction
between driving force and resistance

Question 20

Threshold impact in change

Answer 20

When forces (or stresses) are equal to or less than the strength of the resisting framework then the system remains unchanged
→ No change
Conversely, when forces (or stresses) exceed the strength, then the system goes into disequilibrium - the system will respond by trying to adjust to the
imbalance (e.g. erosion, transport, deposition)
→ Change happens

Question 21

What is the Hjulstrom curve?

Answer 21

The Hjulstrom curve shows when sediment will be eroded, transported or deposited

Question 22

Difference between critical erosion velocity curve and settling velocity curve

Answer 22

Critical: Minimum velocity required for particles to be eroded and transported

Settling: velocity required for sediments to be deposited

Question 23

What is the role of feedbacks in landscape evolution?

Answer 23

Once a threshold is exceeded, the system will go into a state of
disequilibrium and will attempt to adjust to the new balance between driving force and resisting framework

Once change is introduced to the system through modification in one variable, it may include changes in other variables – Which may in turn cause a negative or positive response to the initial variable (feedback)

Question 24

How do wildfires influence the Earth’s surface processes and landscape evolution?

Answer 24

○ Soil erosion and sediment transport:
■ Vegetation loss → exposes soil → soil is looser → increasing
susceptibility to erosion
■ Intense rain events following fires → landslides, flashfloods,
destructive debris flows
○ Surface runoff and hydrology:
■ Fires create a hydrophobic (water-shedding) layer in the soil → reducing infiltration and increasing surface runoff → carving new channels and gullies → erosion

Question 25

What are the 3 major types of endogenic processes

Answer 25

○ Igneous activity: movement of molten rock (magma), towards or onto the Earth's surface (think Volcanic eruptions, intrusive rock formations) ○ Epeirogenesis (epeirogeny): broad, vertical uplift or subsidence of large land areas, occurs without significant folding or fracturing (think uplift of continental interiors and plateau formation). ○ Orogenesis (orogeny): formation of mountain belts through intense deformation, often involves faulting, folding, crustal thickening (think Himalayas and Rocky Mountains)

Question 26

What are Tectonics?

Answer 26

Tectonics refer to the broad structures of the Earth's crust and the processes of deformation and faulting which give rise to them

Question 27

What are the 3 different types of rocks?

Answer 27

Igneous, Sedimentary, Metamorphic

Question 28

What are the formation processes of the 3 rock types?

Answer 28

Igneous: ○ Rocks solidify and crystallize directly from the cooling of magma (often called primary). ○ Their formation process is an exothermic process (it loses heat) and involves a phase of change from liquid to the solid state. Sedimentary: ○ SEDIMENTARY rocks form from the compaction and cementation (lithification) of eroded and deposited sediments (often called secondary). ○ Weathering and erosion, transportation and deposition are key processes Metamorphic: ○ Rocks form when any igneous or sedimentary rock is going through physical or chemical changes under pressure and increased temperature. ○ This often involves burial (leads to rise in temperature and pressure). ○ The metamorphic changes in the minerals always move in a direction designed to restore equilibrium

Question 29

What are the 2 layers of the outer part of Earth?

Answer 29

Lithosphere (rigid) and Asthenosphere (plastic)

Question 30

What is the crust?

Answer 30

The crust overlies the mantle and is the Earth's hard outer shell and in relation with the other layers the crust is much thinner. It “floats” upon the softer, denser mantle. The crust is made up of solid material, but these materials are not the same everywhere.

Question 31

Differences between oceanic and continental crusts:

Answer 31

Oceanic: denser, thinner (6 - 11 km), rocks much younger, sima (silica and magnesium), consists mainly of basalt which is dark, fine and gritty volcanic structure, formed out of very liquid lava Continental: lighter, thicker (30 - 40 km), sial (silica + aluminium), older, igneous rocks. Divided into: 1. Upper part: granite 2. Lower part: basalt and diorite

Question 32

What is the mantle?

Answer 32

The layer above the core is the mantle. It starts ~10 km below the oceanic crust and ~30 km below the continental crust surfaces. The mantle is divided into the inner mantle and the outer mantle. It is about 2,900 km thick and makes up nearly 84% of the Earth's total volume.

Question 33

Differences between outer and inner mantle

Answer 33

The outer (upper) mantle is a lot thinner than the inner mantle. Extends from 10 km and 300 km below the surface of the earth. You can divide the outer mantle into two different layers: ● The outer layer of the outer mantle consists of the same material but is stiffer because of its lower temperature ● The bottom layer is semi-liquid (plastic) rock and probably consists of silicates of iron and magnesium. The temperature in this part is between 1400ºC and 3000ºC and the density is between 3.4g/cm³ and 4.3g/cm³. Inner Mantle: the lower mantle extends from 300 km to 2,890 km below the earth’s surface. The average temperature is 3000ºC, nevertheless the rock is solid because of the high pressures. The lower mantle probably consists of sulphides and oxides of silicon and magnesium. The density is between 4.3g/cm³ and 5.4g/cm³.

Question 34

What are the 2 layers of the core?

Answer 34

Outer Core: The outer core extends from 2,890-5,150 km below the Earth's surface. The outer core is liquid and consists of iron, some nickel and about 10% sulphur and oxygen. The temperature in the outer core is about 4000-5000ºC. The density of the outer core is between 10 g/cm³ and 12.3g/cm³. ■ Inner Core: Extends from 5,150-6,370 km below the Earth's surface and consists of iron, nickel and some lighter elements (probably sulphur, carbon, oxygen, silicon and potassium, and is ~5000-6000 ºC. Because of the high pressure, the core is solid. The average density of the core is about 15g/cm³.

Question 35

How do we know what is inside the Earth?

Answer 35

Volcanoes and Igneous Intrusions Gravity measurements, magnetism Seismology

Question 36

What forces cause mountains to rise and lift layers of rocks kilometers above sea level?

Answer 36

Isostasy Continental drift Seafloor spreading

Question 37

What is isostasy?

Answer 37

Definition: the state of gravitational equilibrium between the Earth’s crust and mantle, such that the crust ”floats” at an elevation that depends on its thickness and density. The block rises if material is removed from the block – and sinks if material is deposited on the block Isostasy explains the elevations of continents and the depths of ocean floors as determined by vertical movements of Earth’s crust

Question 38

What is continental drift?

Answer 38

Parts of the Earth's crust slowly drift atop a liquid core.

Question 39

What are the early evidence for Pangea?

Answer 39

Patterns of geology, fossils, glacial deposits (glaciation event that spilled across all of the continent)

Question 40

When did Pangaea start to break up?

Answer 40

Jurassic period, continents separating into land masses by the end of cretaceous

Question 41

What four major scientific developments spurred the formulation of the plate-tectonics theory

Answer 41

(1) demonstration of the ruggedness and youth of the ocean floor (2) confirmation of repeated reversals of the Earth magnetic field in the geologic past (3) emergence of the seafloor-spreading hypothesis and associated recycling of oceanic crust (4) precise documentation that the world's earthquake and volcanic activity is concentrated along oceanic trenches and submarine mountain ranges

Question 42

Topography vs Bathymetry

Answer 42

■ Topography = the variation in the shape and undulations of Earth’s surface ■ Bathymetry = the same, but when submerged by water, including lakes, rivers and oceans.

Question 43

Relief vs topography

Answer 43

Relief: Vertical elevation differences upon a surface Topography: The general term for the undulations and other variations in the shape of Earth's surface

Question 44

What are the 3 general categories of uplifted crust through endogenic processes?

Answer 44

■ Tectonic mountains and landforms, produced by active folding, faulting, and crustal movements ■ Volcanic landforms, formed by the surface accumulation of molten rock from eruptions of subsurface materials ■ Residual mountains and stable continental cratons, consisting of inactive remnants of ancient tectonic activity

Question 45

What are the 2 types of plate boundaries?

Answer 45

Convergent and Divergent

Question 46

What are the plate tectonics paradigm (or the 2 theories combined to form plate tectonics paradigm)

Answer 46

Continental drift and seafloor spreading

Question 47

What features can the plate tectonic theory explain?

Answer 47

■ It explains the locations of earthquakes and volcanoes. ■ It explains mountain building and rock deformation on the continents, and even, in fact, describes the shapes and locations of the continents. ■ It also helps us understand the youthful age of the seafloor and the unusual distribution of fossil and living organisms on the continents

Question 48

What are the distinct tectonic landforms resulting from 2 processes?

Answer 48

Physical stress: folding and faulting Igenous activity: volcanism and igneous intrusions

Question 49

What are the 3 types of convergent margins?

Answer 49

Subduction, convergent, transform fault

Question 50

Differences between folding and faulting?

Answer 50

Folding: bending due to compressional stress, occurs under lower stress and plastic deformation Faulting: breaking, happens when rocks fracture under brittle (stressed) conditions, often related to tectonic activity

Question 51

What does folding and faulting, respectively, creates?

Answer 51

Folding: anticlines / synclines Faulting: fault planes, fault scarps

Question 52

What are the 3 types of faults?

Answer 52

Normal: caused by tension, hanging wall moves down relative to footwall (divergent plate boundary) Reverse or thrust: caused by compression, hanging wall moves up relative to footwall (convergent boundary) Strike-slip: occurs from lateral-shearing (transform plate boundary)

Question 53

Focus vs epicenter of earthquake

Answer 53

Focus: where earthquake happens Epicenter: The location on crust above

Question 54

How is an earthquake classified

Answer 54

On the basis of damage intensity or magnitude of energy released

Question 55

What is tephra?

Answer 55

Airborne lava and ash

Question 56

Effusive vs explosive lava flows

Answer 56

Whether an eruption is explosive or effusive largely depends upon the amount of gas in the magma. Explosive: If a lot of gas is trapped within high viscosity magma, pressure will build and build until eventually the magma erupts explosively out of the volcano Effusive: If a magma has low viscosity (it is runny), gas can escape easily, so when the magma erupts at the surface it forms lava flows.

Question 57

What is a lava dome?

Answer 57

If a magma rises very slowly within the conduit, or the throat of the volcano, all the gas can escape. When the magma is viscous (or sticky), it can’t flow when it reaches the surface, so it builds up forming a lava dome.

Question 58

What are the 3 types of volcanoes?

Answer 58

Composite: Composite volcanoes tend to have steep sides and a distinct conical shape. A mountain produced by a series of explosive erup­tions is a composite volcano, formed by multiple layers of lava, ash, rock, and pyroclastics. Cinder: A cinder cone volcano is a steep, conical hill made of volcanic ash, cinders, and other pyroclastic materials ejected during explosive eruptions. Shield: A typical mountain landform built from effusive erup­tions is gently sloped, gradually rising from the surround­ing landscape to a summit crater, above hot spots and continental rift valleys

Question 59

What is pumice?

Answer 59

The violent separation of gas from lava may produce rock froth called pumice. In many eruptions, the froth is shattered explosively into small fragments that are hurled high into the air in the form of volcanic cinders (red or black), volcanic ash (commonly tan or gray), and volcanic dust.

Question 60

Where does lava flows?

Answer 60

Lavas either flow through breaks in the crater wall or issue from fissures on the flanks of the cone

Question 61

What is a dike?

Answer 61

Lava, solidified within the fissures, forms dikes that act as ribs which greatly strengthen the cone

Question 62

Lava plateaus vs domes

Answer 62

In some shield volcano eruptions basaltic lava pours out quietly from long fissures instead of central vents and floods the surrounding countryside with lava flow upon lava flow, forming broad plateaus. Lava domes are formed by relatively small, bulbous masses of lava too viscous to flow any great distance; consequently, on extrusion, the lava piles over and around its vent.

Question 63

Difference between Anthropocene and Climate Change

Answer 63

Climate change is a major consequence of the Anthropocene, but the Anthropocene include other human-driven changes: ■ biodiversity loss, pollution, deforestation, large scale sea and landform alterations

Question 64

What is weathering?

Answer 64

Weathering is the process where rocks are worn away or broken down into smaller pieces by wind, water, ice, plants (root penetration)

Question 65

What is erosion?

Answer 65

Erosion happens when broken rocks (through weathering) and sediments are picked up and moved by ice, water or wind.

Question 66

What type of energy drives most weathering and erosion systems that wear down the Earth’s surface (planation)

Answer 66

Exogenic

Question 67

What is climatic geomorphology?

Answer 67

‘Climatic Geomorphology’ is a subcategory which relates climate to why certain landforms form under a given set of climate conditions ○ Mass wasting landforms ○ River response and form ○ Coastal processes ○ Glacial landforms ○ Periglacial landforms

Question 68

How does climatic geomorphology provide essential context for understanding weathering, erosion, and mass wasting

Answer 68

By linking geomorphic processes to climate zones Geomorphic mechanisms vary in type and rate according to the particular climatic zone in which they function

Question 69

What does climate controls?

Answer 69

weathering rates, erosion, and sediment transport.

Question 70

What are some key climatic factors?

Answer 70

Temperature, precipitation and vegetation cover

Question 71

What are morphoclimatic zones?

Answer 71

In climatic geomorphology, morphoclimatic zones are areas which are characterised by landforms associated with a particular climate

Question 72

Spatial variations of landforms in different climatic regions are caused by what?

Answer 72

Spatial variations in climatic parameters (e.g. temperature, humidity, precipitation etc.) and their influences on weathering and erosion

Question 73

The climatic geomorphology theory divides the world into 9 morphogenetic regions (or zones) on the basis of two climatic parameters

Answer 73

Mean annual rainfall and mean annual temperature

Question 74

Main type of weathering in different climates

Answer 74

Humid tropical climate: intense chemical weathering Polar and alpine climates: Frost action Arid and semiarid climates: Physical weathering

Question 75

How does climate change affects geomorphic processes?

Answer 75

○ Increased extreme weather events (flooding, landslides). ○ Desertification and land degradation. ○ Permafrost thaw and slope instability.

Question 76

What are the 2 main types of weathering?

Answer 76

Physical (also called disintegration or mechanical weathering): the breakdown of rock into smaller pieces by physical processes (ice, wind, water, gravity, plants, animals). Chemical (also called decomposition): the process by which rocks break down as a result of chemical reactions (caused by water, weak acids and bases, and air).

Question 77

Why does weathering occur?

Answer 77

The physical and chemical nature of materials formed in the Earth's interior are characteristically in disequilibrium with conditions occurring on the surface. ○ Because of this disequilibrium, these materials are easily attacked, decomposed, and eroded by various chemical and physical surface processes.

Question 78

Weathering converts rocks to what?

Answer 78

Regolith (or soil) an unconsolidated surface layer of weathered rocks Regolith refers to material covering the surface. Regolith is a layer that includes fractured and weathered rocks, eruptive volcanic material, sediments, gasses, water and biota.

Question 79

What is the normal sequence of processes in landscape development?

Answer 79

Weathering --> Erosion --> Transport --> Deposition

Question 80

What is erosion?

Answer 80

The removal or entrainment of earth materials by an external force, for example running water

Question 81

What is the primary effect of physical weathering?

Answer 81

The gradual reduction in strength of bedrock and large rock fragments and boulders by breaking it into progressively smaller pieces of rock.

Question 82

What are the 4 common types of physical weathering?

Answer 82

Frost action / insolation: Thermal expansion and contraction: heating and cooling of rock causes expansion and contraction + Ice wedging occurs when water fills in a crack or a pore, expands because it freezes and splits the rock apart Exfoliation / unloading: A general term that refers to sheets of rock breaking off an exposed bedrock surface also expressed as ’uniform release of internal stresses due to unroofing’. Exfoliation is caused by the release of pressure, meaning unloading within the rock. + Thermal expansion and contraction - Heating and cooling of rock causes expansion and contraction Abrasion: When rocks grind against other rocks or against each other, making them less angular (more rounded). Root wedging: Roots wedge into pores and crevices. When the roots grow, the rock splits. Lichens and mosses grow on rocks. Lichens produce weak acids that chemically weather rock

Question 83

What are the 2 types of chemical weathering?

Answer 83

Oxidation: The breakdown of rock by oxygen and/or water, often giving iron-rich rocks a rusty-coloured weathered surface Carbonation: acidic rain or acidic water dissolving limestone

Question 84

Factors influencing rates of chemical weathering

Answer 84

○ Mineral size/surface area of the material: Smaller particles have higher surface area to volume, therefore faster chemical weathering rates ○ Composition: different minerals have variable solubility in fluids ○ Climate: temperature, water chemistry, type and amount of vegetation

Question 85

Where does physical and chemical weathering dominates?

Answer 85

Physical: Dominates in environments with moderate precipitation and freeze-thaw cycles Chemical: Dominates in warm, wet places

Question 86

Which type of weathering is more effective?

Answer 86

Physical

Question 87

What factors control the amount and rates of weathering?

Answer 87

Climate, hardness of material and surface area of material

Question 88

Transport limited vs detachment limited landscapes

Answer 88

Transport limited: weathering processes are efficient at producing debris (loose rock material) but transport processes are inefficient at removing it from the landscape. These areas are generally soil covered. Detachment limited: landscapes without soil cover

Question 89

What factors control the movement of materials?

Answer 89

○ Shear stress: amount of force applied to a component ○ Shear strength: a material’s ability to withstand stress/resistance of the material ○ Slope stability: relationship between the forces disturbing the material and the resistance of the existing framework

Question 90

The response of slope materials to stress is determined by what?

Answer 90

Their strength = the ability to resist deformation and fracture without significant failure.

Question 91

What is a talus deposit?

Answer 91

Large rock fragments consisting of unconsolidated material transported and deposited on slopes. Gravity is main transport agent

Question 92

What is a collovium deposit?

Answer 92

Finer material of unconsolidated material transported and deposited on slopes. Gravity is main transport agent.

Question 93

What are the classification of mass movements

Answer 93

Flow, slide and heave

Question 94

What is the angle of repose?

Answer 94

The max slope or angle at which loose material (e.g. soil or sand) remain stable. The angle of repose varies greatly with the composition of material, grain size and shape of material as well as water content.

Question 95

What are the 4 main agents initiating erosion?

Answer 95

Gravity, water, glaciers and wind. Several things in common: they all carry sediments only when there is enough energy of motion and drop load of sediments when energy of motion decreases

Question 96

The proportion of precipitation that flows down a slope surface rather than infiltrating can depend on what?

Answer 96

The intensity and duration of precipitation as well as the properties of the slope surface.

Question 97

What are the erosion types produced by water?

Answer 97

Raindrop splash Interrill and rill Ephemeral gully Permanent gully Notch Stream Channel

Question 98

What is rainsplash erosion?

Answer 98

Direct movement of particles or dislodged by removal of supporting particles. Slope gradient and surface characteristics impacts rainsplash erosion.

Question 99

What is slope wash/sheet flow erosion and 2 subtypes

Answer 99

Movement of water across a slope surface. It is not a uniform flow, but often channeled flow - Rills: sustained concentrated flows can generate non-permanent microchannels - Gullies: enlarged rills and permanent part of a channel network.

Question 100

What is mass movement / wasting?

Answer 100

The downslope movement of a mass of surface materials, such as soil, rock, or mud. Caused by gravity. Mass movement sediments tend to be angular (sharped, jagged, irregular) and unsorted (mixed up, all different sizes)

Question 101

What are some slide/slump movement?

Answer 101

‘Soil creep’ – Slow, gradual downhill movement For slides/slumps, failure occurs along a well-defined shear plane. Blocks of material within the failure may move as coherent units, preserving relict structures. Solifluction: slightly faster down slope movement of materials that have a high water content. Occurring in cold regions. Rotational landslides - Fairly rapidly!

Question 102

What are flow movements?

Answer 102

Landslides, faster than slides/slump movements. Can be avalanches, debris flow, earth flows and mudflows For flows, shear occurs throughout the moving mass and there is no well defined shear plane. Material is disrupted throughout the flow.