GEOGRAPHY EXAM 5

antarctica has what percentage of global ice?

90%

glacial valley shape

U-shape

river valley shape

V-shape

cirque

a broad amphitheater hollowed out at the uppermost head of a glacial valley very steep, perpendicular, head and side walls and a floor that is either flat, gently sloping, or even gouged enough to form a basin marks the place where an alpine glacier originated

oxbow lake

a cutoff meander that initially holds water

speleothems

a feature formed by precipitated deposits of minerals on the wall, floor, or roof of a cave

recessional moraine

a glacial deposit of till formed during a pause in the retreat of the ice margin

terminal moraine

a glacial deposit of till that builds up at the outer most extent of ice advance

bergschrund

a large crevice opens at the top of the glacier, exposing part of the headwall to frost wedging people can fall into the crack and are preserved-they move through the ice and come out at the end

flood plains

a low-lying, nearly flat alluvial valley floor that is periodically inundated with flood waters formed where a meandering stream flows across a wide, nearly level valley floor

stream capacity

a measure of the amount of solid material a stream has the potential to transport, normally expressed as the volume of material passing a given point in the stream channel during a given time interval

stream competence

a measure of the particle size a stream can transport, expressed by the diameter of the largest particles that can be moved depends mainly on flow speed, with the power of the water generally increasing by the square of its speed- if flow doubles (2) squared= 4 times the power if flow triples (3) squared= 9 times the power

knickpoint

a sharp irregularity (waterfall, rapid, cascade) in a stream-channel profile

collapsed caves

a sinkhole that results from the collapse of the roof of a subsurface cavern may have vertical walls or overhanging cliffs

horn

a steep-sided, pyramid-shaped mountain peak formed by expansive quarrying of the headwalls where three or more cirques intersect

hanging valley

a tributary glacial trough, the bottom of which is considerably higher than the bottom of the principal trough that it joins

glacial troughs

a valley reshaped by an alpine glacier, usually u-shaped

the sides of a hot spring are colorful due to

algae growth

depositional landform

all materials moved & deposited by glacier "Drift"

accumulation zone

all parts of the glacier above equilibrium line

ablation zone

all parts of the glacier below equilibrium line

Drainage basins/ watershed

all the area that contributes overland flow, streamflow, and groundwater to that stream consists of a stream's valley bottom, valley sides, and those portions of the surrounding interfluves that drain toward the valley every stream of any size has its own, but for particular purposes the term is often reserved for major streams

periglacial zone

an area of indefinite size beyond the outermost extent of ice advance that was indirectly influence by glaciation

glacial erratics

an isolated large boulder carried by the glacier and dropped

a 100 year flood has what probability in any given year?

anytime 1% chance

glacier flow versus glacier advance

as long as a glacier exists, the ice in it is flowing-this does not necessarily mean that the outer edge of the ice is advancing the ice in a glacier always moves forward, but the outer margin of the glacier may or may not be advancing, depending on the balance between accumulation and ablation

basal slip

at the bottom of the glacier, in which the entire mass slides over its bed on a lubricating film of water caused by water and heat

Bering Strait

between present-day Alaska and Russia was a dry land bridge, allowing migration of both animals and humans

saltation

bouncing of material on bottom of river bed

valleys can also be extended through

building of deltas at the terminus of a river

kettle

depressions formed when large blocks of ice left by a retreating glacier become surrounded or even covered by glacial drift

terminal/ recessional moraine

develop as glacier recede ridges that mark positions where the ice from was temporarily stabilized during the final retreat of the glacier concave arc that budge outward in direction of ice movement

trellis pattern

develops as a response to underlying structural control alternating bands of tilted hard and soft strata, with long parallel streams linked by short, right-angled segments ridge-and-valley section of Appalachian Mountains Ouachita Mountains in western Arkansas

during glacial periods sea levels

drop

example of erosional landform

finger lakes in NY great lakes formed by glacial erosion Roche Mountonnee- glacial landform

cutoff meanders and oxbow lakes occurs on a

flood plain

plastic flow of ice

flow inside glacier speed ranges from a few cm/day to 100ft in a day faster in center vs edges

esker

formed from river deposits when there was a river inside the glacier

as Antarctica gets warmer melting ice makes oceans

fresh water (less salty)= more ice ice does not freeze as easily (putting down ice when it snows)

moraines

glacier-deposited landforms composed entirely or largely of till growth at the terminus of a glacier

two continental ice sheets remaining

greenland & antarctica

time since pleistocene is called

holocne

hot springs

hot water at Earth's surface resulting from underground water coming in contact with heated rocks or magma and has been forced upward

as stream discharge increases what happens to speed?

increases

point bar

inside of curve where water moves slowest alluvium is likely to accumulate

pleistocene lakes

large freshwater lakes that formed in basins of interior drainage because of higher rainfall and/or lower evaporation during the Pleistocene

lateral moraine

largest depositional feature produced by a mountain glaciation well defined ridges of unsorted debris built up along the sides of valley glaciers

pleistocene

last named ice age began 2.59 mybp on Thursday November 12 at 4 am eded about 11,700 mybp

dissolution process

limestone combines with water and carbon dioxide to produce carbonic acid

soda straws

long, slender, hang down from ceiling; little more than one water drop wide, these delicate hollow tubes may eventually grow into stalactites

drumlin

low, elongated hill aligned parallel with direction ice movement- the end of the drumlin facing the direction which it came is blunt and slightly steeper than the opposite end

u shape valley

maximum glaciation

dedentric pattern

most common drainage pattern random merging of streams, with tributaries joining larger streams irregularly but always at an angle smaller than 90 not controlled by underlying structure

sinuous channel

much more common than straight winding channel found in almost every type of topographic setting sinuosity increases with decreasing gradient

braided channel

multiplicity of interwoven and interconnected channels very flat high load of sediment typical of glacial melt water and areas with dry seasons

where is maximum velocity?

near the surface and in the middle

snowflakes--granular snow---

neve---glacier ice

a fumarole emits

no water, just steam

density increases between

nèvè and glacial ice glacial ice becomes a blueish color

intermittent or ephemeral streams are

only rarely carrying water

cutbank

outside of curve where water moves fastest

nunataks

pinnacles rising able the ice of a highland icefield

how have humans accelerated the forming of sinkholes?

population growth in FL put a heavy drain on its underground water supply, causing drawdown of the water table- as a result, the number and size of sinkholes are increased

v-shaped valley

pre-glacial topgraphy

karst landscapes do not have many..

rivers on the surface, they usually disappear into the caverns

rock shapes- glacial vs rivers

rounded rocks are river rocks

karst topography

rugged hilly areas that has been shaped almost entirely by solution action of limestone formations set of processes & assemblage of landforms

west Antarctica is made up of

scattered islands, not a continuous landmass

meandering channel

serpentine course nearly flat landscape small gradient continuously changes course

straight channel

short uncommon controlled by underlying geologic structure

most of FLs scenic lakes begin as

sinkholes

what is the most common feature of a karst landscape?

sinkholes

moulins

steep drainage shafts in the ice

graded stream

stream in which the gradient just allows the stream to transport its load more theoretical than actual because equilibrium is so difficult to achieve

alluvium

strem deposited sediment typically smooth and round display distinct strata often sorted- deposit is comprised of rocks of just about the same size

disappearing streams

surface runoff that does become channeled does not usually go far before it disappears into a sinkhole or joint crack

rain and snow water percolates into rocks, travels into heated area and comes to the surface depositing

tavertine

white area on mammoth hot springs looks like snow or ice but its is really

tavertine

even in a straight stream the thalweg..

tends to be slightly sinuous

Thalweg

the course of the deepest and fastest flow

valley deepening

the effect of downcutting (action of stream to erode a deeper channel; occurs when stream is flowing swiftly and/or flowing down a steep slope) produces a deep valley with steep sides and often a V-shaped cross section

interfluve

the higher land above the valley walls that separates adjacent valleys some are ridgetops or mountain crests with precipitous slopes, others are simply broad and flattish divides between drainage systems all parts of the terrain not in a valley are part of an interfluve on a interfluve, water will move downslope through unchanneled overland flow until it reaches the lip of the interfluve. there, as the water drops off the lip of the interfluve into the first small gullies of the valley system, streamflow begins

col

the sharp-edged pass or saddle through the ridge if two adjacent cirques on opposite sides of a divide are being cut back enough to remove part of the arête between them

ground moraine

till is laid down from underneath the glacier rather than from its edge

Stream ordering

two numbers that are the same come together, go up 1 length increases w/ order # increase gradient decreases with order # increase

glacial till is

unsorted and unstratified

knickpoint migration

upstream shift in location of a knickpoint due to erosion

West Antarctica

warming faster than East Antarctica melting is faster than originally predicted ice is 8000 ft thick some "dry valleys" with no ice

is the holocene post-glacial or inter-glacial

we dont know

dissolution is more rapid in

wet enviornments

arête

when several cirques have been cut back into an interfluve from opposite sides of a divide, a narrow, jagged, serrated spine of rock may be all that is left of the ridge crest

column

when stalactite and stalagmites come together

piedmont glacier

when the glacier terminated in a nearby valley

glacial calving

when the ice shelf breaks off pieces into icebergs

medial moraine

where a tributary glacier joins a main valley glacier, their lateral moraines (and debris carried on top of the ice) become united at the intersection and often continue together down the middle of the combined glacier as a dark band of rocky debris

surface drainage

where sinkholes occur in profusion, they often channel surface runoff into the groundwater circulation, leaving networks of dry valley

drainage divide

where the drainage basin terminates line of separation between runoff that descends in the direction of one drainage basin and runoff that goes toward an adjacent basin can be a sharp ridge between drainage basins, or it can be a more subtle separation of basins in the form of an interfluve

stalagmite

where the drip hits the floor and grows upward

how does urbanization impact lag time?

where there tends to be less infiltration of rain because much of the region is covered with impermeable surfaces such as pavement and buildings, a heavy rain tends to produce greater and faster runoff into local streams than in areas with more permeable surfaces

stalactite

where water drips from the roof, a pendant structure grows slowly downward like an icicle