Geog 160 Geomorphology Final 100 Level College Course

Front 1

calving

Back 1

wastage of a glacier that occurs when large pieces of ice break into the water

Front 2

levee

Back 2

belt of higher ground paralleling a meandering alluvial river on both sides of the stream channel and built up by deposition of fine sediment during periods of overbank flooding

Front 3

patterned ground

Back 3

ground surface bearing polygonal or ring-like features, including stone circles, nets, polygons, steps and stripes, including ice wedge polygons, typically produced by frost action in cold climates

Front 4

permafrost

Back 4

soil, regolith, and bedrock at a temp lower than O degrees celcius or 32 degrees F, found in cold climates of arctic, subarctic, and alpine regions

Front 5

pingo

Back 5

conspicuous conical mound or circular hill, having a core of ice, found on plains of the arctic tundra where permafrost is present

Front 6

talik

Back 6

pocket or region within permafrost that is unfrozen, ranges from small inclusions to large "holes" in permafrost under lakes

Front 7

active layer

Back 7

shallow surface layer subject to seasonal thawing in permafrost regions

Front 8

solifluction

Back 8

tundra (arctic) variety of earthflow in which sediments of the active layer move in a mass slowly downhill over a water-rich plastic layer occurring at the top of permafrost, makes solifluction terraces and solifluction lobes

Front 9

glacial moraine

Back 9

accumulation of rock debris carried by an alpine glacier or an ice sheet and deposited by the ice to become a depositional landform

Front 10

crevasse

Back 10

gaping crack in the brittle surface of a glacier

Front 11

cirque

Back 11

bowl-shaped depression carved in rock by glacial processes and holding the firn of the upper end of an alpine glacier

Front 12

alpine glacier

Back 12

long, narrow mountain glacier on a steep downgrade, occupying the floor of a troughlike valley

Front 13

glacier

Back 13

large natural accumulation of land ice affected by present or past flowage

Front 14

atoll

Back 14

circular or closed-loop coral reef enclosing an open lagoon with no island inside

Front 15

loess

Back 15

accumulation of yellowish to buff-coloured, fine-grained sediment, largely of silt grade, upon upland surfaces after transport in the air in turbulent suspension (like in a dust storm)

Front 16

desert pavement (eolian)

Back 16

surface layer of closely fitted pebbles or coarse sand from which finer particles have been removed

Front 17

floodplains

Back 17

belt of low, flat ground, present on one or both sides of a stream channel subject to innundation by a flood about once annually and underlain by alluvium

Front 18

oxbow lake

Back 18

crescent-shaped lake representing the abandoned channel left by the cutoff of an alluvial meander

Front 19

cutoff

Back 19

cutting-through of a narrow neck of land, so as to bypass the stream flow in an alluvial meander and cause it to be abandoned

Front 20

braided stream

Back 20

stream with shallow channel in coarse alluvium carrying multiple threads of fast flow that subdivides and rejoin repeatedly and continually shifts in position

Front 21

aggradation

Back 21

raising of stream channel altitude by continued deposition of bed load

Front 22

point bar

Back 22

deposit of coarse bed-load alluvium accumulated on the inside of a growing alluvial meander

Front 23

discharge

Back 23

volume of flow moving thru a given cross-section of a stream in a given unit of time, commonly given in cubic meters (feet) per second q=wdv

Front 24

recurrence interval (RI)

Back 24

RI=n+1 over m.
where RI=rec. intervals in years
n=# of years of record
m=rank of flood

Front 25

creep

Back 25

extremely slow downhill movement of soil and regolith as a result of continued agitation and disturbance of the particles by such activities as frost action, temp. changes, or wetting or drying of soil

Front 26

chemical weathering

Back 26

chemical change in rock-forming minerals through exposure to atmospheric conditions in the presence of
water, mainly involving oxidation, hydrolysis, carbonic acid action, and direct solution

Front 27

physical weathering

Back 27

produces regolith from massive rock by action of forces strong enough to fracture rock
E.G.frost action, salt-crystal growth, unloading, wedging by plant roots
AKA mechanical weathering

Front 28

slope processes

Back 28

mass wasting/movement. transportation controlled by gravity, unless water is involved, then it is a fluvial process.
EG. falls, slides, flows, creeps

Front 29

slides

Back 29

fast movement of material, not associated with water

Front 30

rock fall

Back 30

rocks falling through air, resulting landform is talus slope

Front 31

types of slides:

Back 31

translational slides:one layer of rocks slides over another, often accompanied by a rotational slump.
rotational slump: surface block moves along a concave surface

Front 32

flows

Back 32

saturated material, flows as a fluid, increased % of water equals decreased viscosity

Front 33

debris avalanche

Back 33

combination of a fall, flow, and slide. free falling and tumbling across a steep surface at very high speeds, made of mix of soil, rock, ice water, etc. if all snow then snow avalanche

Front 34

talus

Back 34

dry, unconsolidated material, in rocky, mountainous areas, accumulations of mass-wasted materials at bottom of slope, generally at angle of repose, 35 degrees

Front 35

factors altering slope stability:

Back 35

weathering-breaks down cohesion, reduces angle of repose
joint spacing
downslope dip less than slope angle
water-positive pore pressures, increase weight of soil

Front 36

more flows

Back 36

earth flows-20% gravel, slower than debris flow
mudflow-mud, silt, and clay
lahar-volcanic debris flow-from rain and pyroclasts

Front 37

alpine debris avalanche

Back 37

mix of snow, ice, rock

Front 38

effect of dams on fluvial processes:

Back 38

control floods, provide water for irrigation, allow for carry-over storage from snow melt into summer, alter timing of water discharge

Front 39

aquifer

Back 39

material permeable and porous enough to yeild water to springs or wells, unconsolidated sediments esp. alluvial sands and gravels make excellent aquifers

Front 40

deranged drainage system

Back 40

disorderly drainage pattern formed in a recently glaciated area, irregular direction of stream flow,few short tributaries, swamps, and many lakes

Front 41

Mississippi River

Back 41

1993, serious flood, occurred in midsummer, triggered by succession of unprecedented rainfalls in upper Mississippi Basin, monthly rainfall totals highest in years, as water drained from landscape, Mississippi and its tributaries rose, creating flood of turbid water, river went over levees and flooded floodplains, some classed flood level as 500 year level

Front 42

glacier ice

Back 42

very compact and dense, air bubbles trapped in ice crystals,

Front 43

snow line or firn line

Back 43

line above which snow remains during year due to temp and accumulation

Front 44

ablation

Back 44

wastage of glacial ice by both melting and evaporation

Front 45

equilibrium line

Back 45

no net gain or loss, may be at or slightly below snow line

Front 46

movement of glaciers

Back 46

if accumulation zone present glacier moves forward, snout may advance, retreat, or remain stationary

Front 47

3 processes glaciers move by:

Back 47

internal deformation, ice fractures, basal sliding

Front 48

glacial deposit till

Back 48

sediment deposited directly by glacier ice, either supra-glacial-gravels and boulders, angular, or sub-glacial mixture

Front 49

glacial fluvial deposits

Back 49

from meltwater streams at sides or fronts of glacier, sorted sands and gravels, almost no clay or silt

Front 50

glacial lacustrine-marine

Back 50

terminus of glacier in or near standing water, sorted sands, silts, and clays

Front 51

delta

Back 51

sediment deposit built by a stream entering a body of standing water and formed of the stream load

Front 52

point bar

Back 52

where alluvium accumulates as a long, curving deposit of sediment, widening of this deposit creates crescent shaped area of low ground, first stage of floodplain development

Front 53

cut banks

Back 53

when meanders develop narrow necks, which are cut through by water, thus shortening river course and leaving a meander loop abandoned, then sand and silt is deposited across ends of abandoned channel, which makes an oxbow lake

Front 54

colluvium

Back 54

where soil particles rest and accumulate at base of eroding slope

Front 55

alluvium

Back 55

any stream-laid sediment deposit

Front 56

stream's carrying capacity

Back 56

maximum load that can be carried by a stream at a given discharge is a measure of the stream capacity, capacity increases with increase in velocity because more intense turbulence

Front 57

terrace

Back 57

form when a graded stream slowly cuts away the alluvial fill in its valley, steplike alluvial surfaces on both sides of valley, good for agriculture and towns, easily tilled

Front 58

firn

Back 58

layers of snow in the process of compaction and recrystallization

Front 59

alpine glacier

Back 59

ice accumulates in cirque, flows downhill, abrading and plucking down bedrock

Front 60

continental glaciers

Back 60

huge glaciers that cover moderately sloped areas of land

Front 61

glacial outwash plain

Back 61

smooth, sloping plain lying in front of ice margin, formed from stratified drift left by braided streams issuing from the ice, built of layer upon layer of sands and gravels

Front 62

eskers

Back 62

deposit of sand and gravel laid on the floor of the former ice tunnel from large stream in glacier. form ridges after ice has melted away.