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geog 1000 > exam #4 > Flashcards

exam #4 Flashcards

1
Q

Define denudation. What are the elements of denudation

A

lowering of continental surfaces. Weathering, mass wasting, erosion

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2
Q

explain physical and chemical weathering

A

physical: reduces size of rock masses without altering chemical composition

chemical: decomposition of minerals in the rock -> chemical composition of rock changes

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3
Q

what are the processes of physical weathering

A

frost action: freeze/thaw cycles
salt weathering: crystallization breaks up rocks
pressure-release jointing: slab-like layers/sheets break loose
biological forces: plants and organisms

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4
Q

explain the chemical weathering processes

A

1) hydrolysis: granular disintegration
2) hydration:
3) dissolution of carbonates: how weathering of limestone occurs

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5
Q

what is karst topography

A

solution of carbonate rocks (limestone) can result in the landscape being pitted, bumpy surface topography with underground channels and caverns

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6
Q

Which climates do physical and chemical weathering dominate in?

A

physical: drier, cooler climates
chemical: moister, wetter climates

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7
Q

define mass movement

A

process of a body of material is moved downslope under the influence of gravity

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8
Q

the gravity/forces on a slope diagram ***

A
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9
Q

define Fp and Ff

A
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10
Q

define angle of repose and angle of sliding friction

A

angle of repose: steepest angle that can be attained by loose material without moving downslope (typically 33 to 37 degrees). i.e., angle at which sliding ceases

angle of sliding friction: angle at which dry, unconsolidated material fails. i.e., angle at which sliding commences

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11
Q

what does the coulomb equation represent? what is the equation? what are the variables?

A

shear strength = shear stress = normal stress * tan(angle of internal friction) plus cohesion

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12
Q

how does water affect soil cohesion

A

shear strength = shear stress when there is no movement. soil cohesion is low when very dry, low when saturated and high when pores are partly full and under suction

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13
Q

what’s the coulomb equation with water?

A

water affects the normal stress

shear strength = shear stress = (normal stress - porewater pressure) * tan(angle of internal friction) plus cohesion

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14
Q

what’s the factor of safety? is the slope stable are unstable when FoS is > or < than 1

A

FoS = shear strength / shear stress

FoS > 1 = slope stable
FoS < 1 = slope unstable

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15
Q

what are the trigger mechanisms ?

A
  • precipitation, weathering, earthquakes, changes in loading, changes in slope, vegetation changes
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16
Q

is an avalanche a mass movement?

A

NO

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17
Q

all the diagrams for mass movements

A
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18
Q

rissa quick clay slide

A
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19
Q

what’s the difference between isostatic and eustatic changes

A

isostatic: related to land position
eustatic: related to water volume

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20
Q

what are the environmental significance of glaciers..
1. formation of glaciers and ice sheets (iso/eu rise/fall in sea level)
2. further growth of ice sheets (iso/eu uplift/depression of land, rise/fall in sea level)
3. ice sheets melt (iso/eu rise/fall in sea level)
4. decline of ice sheets and glaciers (iso/eu rise/fall of land, rise/fall in sea level and iso/eu rise/fall in sea level)

A
  1. eustatic, fall
  2. isostatic, depression, rise
  3. eustatic, rise
  4. isostatic, rise, fall, eustatic, rise
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21
Q

types of glaciers**

A
22
Q

How can an ice shelve be used/what mechanism to show the sensitivity of climate change in systems?

A

Ground penetrating radar can be used to tell exactly how big the glacier is -> can compare size

23
Q

what’s a surge?

A

rapid onset/increased velocity of a glacier

24
Q

define permafrost, periglacial and active layer

A

permafrost: earth materials that remain at or below 0 degrees for 2 or more consecutive years (perennially frozen ground)

periglacial: areas where cold climates dominate that do not have an ice cover

active layer: soil and rock layer of varying thickness that thaws each summer (seasonally thawed ground)

25
Q

define continuous, discontinuous, mountain, sub sea permafrost

A

continuous: all surfaces (>90%)(besides deep lakes) covered
discontinuous: extensive (50-90%) and sporadic (10-50%) coverage
mountain: when permafrost is present at high elevation but not in adjacent lowlands/valleys
sub sea: determined by history (due to sea being -2 degrees)

26
Q

factors that affect mountain permafrost

A

elevation, surface, subsurface, water availability, snow cover

27
Q

different types of active layers

A

type 1: bedrock
- low ice, thick active layer, high arctic/mountain areas, changes in surface conditions, fast response time

type 2: rock glacier
- high ice, thick active layer, rock glaciers, changes in MAGST/snow depth, slow response time due to high ice content

type 3: mineral soil
- low to high ice, medium active layer, wherever soil s well developed, changes in MAGST/snow depth/vegetation, moderate response time

type 4: organic
- moderate ice, low active layer, lowland/valleys, changes in MAGST, snow depth, forest fire, very slow response time

type 5: submerged
- high ice, shallow active layer, edge of lake, …changes in lake level, dependent on hydrology

28
Q

why did the rissa quick slide happen? where did it occur? why do these formations occur where it did?

A
  • quick clay in Norway
  • area under water then once it disappeared, marine clay deposits were left behind. sodium (+) and clay (-) in ground then the fresh water leeched the salt out (compromised stability)
  • triggers liquified
29
Q

which glaciers are examples of continental glaciers?

A

ice sheets, ice caps, ice fields, ice shelves

30
Q

which glaciers are examples of alpine glaciers?

A

valley glaciers, cirque glaciers, piedmont glaciers, tidewater glaciers

31
Q

if the equilibrium line on a glacier is lower, is the glacier getting bigger or smaller?

A

bigger

32
Q

what does the mass budget tell us?

A

it’s the equilibrium line -> negative vs positive mass balance

tells us about health of glacier. if negative, glaciers getting smaller

33
Q

what are the names of the input/output zones on glaciers? what’s the name of the area where the glacier ends?

A

input: accumulation zone
output: ablation zone
ends: terminus area

34
Q

what are evidence of glacial movement?

A

crevasses, moraines, surges

35
Q

what’s that one specific glacier movement picture of?

A

concentric crevassing

36
Q

what are examples of glacial erosion?

A

polished bedrock, cirques (bowls), tarns (lakes in cirques), u-shaped valleys and fjords, arêtes (2-sided ridge) and horns (3-sided), hanging valleys

37
Q

what’s the deposition of material and ice by water from glaciers called?

A

drift

38
Q

what is permafrost based on? temperature or frozen water?

A

temperature - at or below 0 degrees C for 2+ consecutive years

39
Q

what does MAGST stand for?

A

mean annual ground surface temperature

40
Q

define permafrost table and talik

A

permafrost table: upper limit of permafrost
talik: unfrozen ground within permafrost

41
Q

define aggrading features vs degrading features (periglacial landforms)

A

aggrading: permafrost is growing
degrading: permafrost is thawing

42
Q

in patterned ground, frost sorting is a combination of ___ and ______

A

heaving (vertical motion) and thrusting (horizontal motion)

43
Q

what are pingos and how do they form?

A
  • taliks present under large lake
  • lake drains
  • residual pond
  • saturates soil freezes and expands up
44
Q

is continuous creep slow or fast? which umbrella in mass movements is it under?

A

slow! flows

45
Q

what is solifluction? is it slow or fast? is there a scar? what does it form? which umbrella?

A
  • combination of frost creep and gelifluction
  • slow
  • flows
  • no scar
  • tongue-like lobes
46
Q

what’s the difference. between mud flows and debris flows?

A

mud flows are the fastest, most fluid and most dangerous flow. fine material and water

debris are similar but contain large particles and move a little more slowly

47
Q

define a slide

A

movement along one or more discrete failure surfaces

48
Q

define active layer detachments

A

occur over permafrost as a result of rapid thaw of icy soils over still frozen material …. debris slides

49
Q

define falls

A

vertical (or near) movement of particles through the air

50
Q

where does blockfall principally occur?

A

in frozen sediments undermined by thermal erosion

51
Q

what’s a complex movement? what does the nines creek photo show?

A

complex movement is a mixture of any of the other types of mass movements

  1. earthquake triggered collapse of thin ice cap & mass of ice blocks and rock fell vertically (fall)
  2. the mass of ice blocks and rock rushed down the valley (flow)
  3. debris and ice spread out (slide)
52
Q
A

geog 1000 (4 decks)

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