exam #4

Question 1

Define denudation. What are the elements of denudation

Answer 1

lowering of continental surfaces. Weathering, mass wasting, erosion

Question 2

explain physical and chemical weathering

Answer 2

physical: reduces size of rock masses without altering chemical composition

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

Question 3

what are the processes of physical weathering

Answer 3

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

Question 4

explain the chemical weathering processes

Answer 4

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

Question 5

what is karst topography

Answer 5

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

Question 6

Which climates do physical and chemical weathering dominate in?

Answer 6

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

Question 7

define mass movement

Answer 7

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

Question 8

the gravity/forces on a slope diagram ***

Question 9

define Fp and Ff

Question 10

define angle of repose and angle of sliding friction

Answer 10

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

Question 11

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

Answer 11

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

Question 12

how does water affect soil cohesion

Answer 12

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

Question 13

what’s the coulomb equation with water?

Answer 13

water affects the normal stress

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

Question 14

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

Answer 14

FoS = shear strength / shear stress

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

Question 15

what are the trigger mechanisms ?

Answer 15

• precipitation, weathering, earthquakes, changes in loading, changes in slope, vegetation changes

Question 16

is an avalanche a mass movement?

Answer 16

NO

Question 17

all the diagrams for mass movements

Question 18

rissa quick clay slide

Question 19

what’s the difference between isostatic and eustatic changes

Answer 19

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

Question 20

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)

Answer 20

1. eustatic, fall
2. isostatic, depression, rise
3. eustatic, rise
4. isostatic, rise, fall, eustatic, rise

Question 21

types of glaciers**

Question 22

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

Answer 22

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

Question 23

what’s a surge?

Answer 23

rapid onset/increased velocity of a glacier

Question 24

define permafrost, periglacial and active layer

Answer 24

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)

Question 25

define continuous, discontinuous, mountain, sub sea permafrost

Answer 25

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)

Question 26

factors that affect mountain permafrost

Answer 26

elevation, surface, subsurface, water availability, snow cover

Question 27

different types of active layers

Answer 27

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

Question 28

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

Answer 28

- 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

Question 29

which glaciers are examples of continental glaciers?

Answer 29

ice sheets, ice caps, ice fields, ice shelves

Question 30

which glaciers are examples of alpine glaciers?

Answer 30

valley glaciers, cirque glaciers, piedmont glaciers, tidewater glaciers

Question 31

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

Answer 31

bigger

Question 32

what does the mass budget tell us?

Answer 32

it's the equilibrium line -> negative vs positive mass balance tells us about health of glacier. if negative, glaciers getting smaller

Question 33

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

Answer 33

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

Question 34

what are evidence of glacial movement?

Answer 34

crevasses, moraines, surges

Question 35

what's that one specific glacier movement picture of?

Answer 35

concentric crevassing

Question 36

what are examples of glacial erosion?

Answer 36

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

Question 37

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

Answer 37

drift

Question 38

what is permafrost based on? temperature or frozen water?

Answer 38

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

Question 39

what does MAGST stand for?

Answer 39

mean annual ground surface temperature

Question 40

define permafrost table and talik

Answer 40

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

Question 41

define aggrading features vs degrading features (periglacial landforms)

Answer 41

aggrading: permafrost is growing degrading: permafrost is thawing

Question 42

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

Answer 42

heaving (vertical motion) and thrusting (horizontal motion)

Question 43

what are pingos and how do they form?

Answer 43

- taliks present under large lake - lake drains - residual pond - saturates soil freezes and expands up

Question 44

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

Answer 44

slow! flows

Question 45

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

Answer 45

- combination of frost creep and gelifluction - slow - flows - no scar - tongue-like lobes

Question 46

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

Answer 46

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

Question 47

define a slide

Answer 47

movement along one or more discrete failure surfaces

Question 48

define active layer detachments

Answer 48

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

Question 49

define falls

Answer 49

vertical (or near) movement of particles through the air

Question 50

where does blockfall principally occur?

Answer 50

in frozen sediments undermined by thermal erosion

Question 51

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

Answer 51

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)