Exam 3

cirque

a bowl-shaped erosional landform scooped out at the head of a valley

barrier island

a broader, more extensive landform than a barrier beach

ice age

a cold period that may last several million years

continental glacier (ice sheet)

a continuous mass of ice that covers a large scale

longshore current

a current that is parallel to the coast that depends on wind direction and wave direction

alluvial fans

a feature formed by stream deposition referring to the feature that forms at the mouth of a canyon where an ephemeral stream channel exits into a wider valley

meander

a feature formed by stream erosion referring to a sinuous snake-like pattern

point bar

a feature formed by stream erosion referring to the inner portion of a meander experiencing slow water velocity and higher deposition

undercut bank (cutbank)

a feature formed by stream erosion referring to the process of fast water velocity scouring the outer curve of a river

oxbow lake

a feature formed by stream erosion referring to when a looping meander becomes isolated from the rest of the river as a new channel is formed enclosing it

wetlands

a feature that is saturated with water enough of the time to support plants that grow in water or wet soil

alpine glacier

a glacier in a mountain range

tidewater glacier

a glacier that ends up in the sea

lateral moraine

a landform that forms along each side of a glacier

mixing zone

a layer of the ocean in which variations in water temperature and solutes blend rapidly; makes up 2% of the oceans

thermocline (transition zone)

a layer of the ocean more than 1 km deep of decreasing temperature gradient that lacks the motion of the surface

deep cold zone

a layer of the ocean where water temperatures near 0*C

base level

a level below which a stream cannot erode its valley

floodplains

a low-lying area formed by erosion with surfaces that reflect centuries of recurring flooding and deposition of sediment

levee

a mound of sediment that parallels both sides of the stream

exotic stream

a river system that begins in moist regions and flows downstream into arid landscapes where high potential evapotranspiration and withdrawals for agriculture and settlements may reduce the discharge

esker

a sinuously curving, narrow ridge of coarse sand and gravel

glacier

a slow moving river of ice

graded stream

a stream that has just enough energy to transport its sediment load

ungraded stream

a stream that is actively eroding or depositing material in its channel so that its gradient is adjusted to carry the sediment load

competence

a stream's ability to move particles of a specific size

ice field

a type of continuous ice cover that extends in a characteristic elongated pattern in a mountainous region

ice cap

a type of continuous ice cover that is roughly circular and covers an area less than 50,000 km2

periglacial

a type of environment found in very cold climates, often around glaciated areas

laminar (flow)

a type of stream flow when water particles move in the same direction in parallel paths

turbulent (flow)

a type of stream flow when water particles move randomly and cross paths in many directions

mean sea level (MSL)

a value based on average tidal levels recorded hourly at a given site over many years

dune

a wind-sculpted accumulation of sand

drainage basin

also called a watershed, this collects water and sediment from many tributaries

interfluve

an area of high ground that separates two adjacent river valleys

roche moutonnee

an asymmetrical hill of exposed bedrock formed by glacial erosion

Little Ice Age

an episode of cold between the years of 1200 and 1900

Medieval Warm Period

an episode of warming during the period between 800-1200 AD

erg desert (sand sea)

an extensive area of dunes

paleolakes (pluvial lakes)

ancient lakes in the United States

submergent coastline

another word for a depositional coastline

emergent coastline

another word for an erosional coastline

ocean acidification

as the ocean absorbs excess carbon dioxide from the atmosphere, this happens

tidal bulges

because the gravitational pull on the oceans is different on opposite sides of the earth, two areas of raised water form called ____

jetties

block material from harbor entrances

atolls

circular, ring shaped reefs that encircle submerged islands

valley glaciers

cirque glaciers often flow down to become ____

tidal flats (salt marshes)

coastal wetlands flooded and drained by tides

crevasses

cracks in glaciers that result from friction with valley walls or from tension or compression

8.2

current average pH of the ocenas

drumlin

deposited till that was streamlined in the direction of continental ice movement is called a ____

saltation

describes movement of particles by water and wind transport of grains larger than 0.2 mm

drainage density

determined by dividing the total length of all stream channels in the basin by the area of the basin

solutes

dissolved solids

yardangs

distinctive, elongated, ridge formations left behind by deflation and abrasion

solifluction

during the summer thaw cycle, the upper layer of soil regolith starts to flow downslope during the process of ____

waves

friction between wind and the ocean surface

loess

glacial silt

flood

high water that overflows the natural bank along any portion of a stream

lagoon

if tidal flats or salt marshes are completely cut off from the bay, this forms

waterfalls

large stream nickpoints

groins

long and narrow structures built into the sea to slow drift action along the coast (built straight out into the sea and parallel into the coast)

breakwaters

long narrow structures built parallel to the shore to create zones of still water near the coastline

barrier beaches

long, narrow, depositional features, usually of sand, that form offshore parallel to the coast

continental divides

major drainage divides on a continental scale

alluvium

mineral fragments deposited by running water

estuaries

partly enclosed coastal bodies of brackish water with one or more inflowing freshwater streams

depositional coastline

places of active deposition of sediments on the coast

fringing reefs

platforms of coral rock surrounding volcanic islands

headlands

protruding landforms of erosion-resistant rocks formed where shallowing water depth causes waves to drag on the bottom

barrier reefs

reefs that enclose lagoons

swells

regular patterns of smooth, rounded waves on the open ocean

fluvial

related to rivers

erratics

retreating ice leaves behind transported rocks as ____

gullies

rills can develop into deeper ____

ultimate base level

sea level

coral

simple marine animal with a small, cylindrical body called a polyp

kame

small hills of poorly sorted sand and gravel that are deposited by water or ice in crevasses, or in surface indentations

tarns

small mountain lakes called ____ often form in cirques where valley glaciers originate

outwash

sorted glacial deposit sediments that occur when glacial meltwater deposits the heaviest rocks first

perennial streams

streams that flow all year

intermittent streams

streams that flow for several weeks of months each year and may have some groundwater inputs

ephemeral streams

streams that flow only after precipitation and are not connected to groundwater systems

sheetflow

surface water initially moves downslope in a thin film of ____

coast

the area that continues inland from high tide to the first major landform change

drainage pattern

the arrangement of stream channels in an area

annular drainage pattern

the arrangement of stream channels in an area that is produced by structural domes or basins with concentric patterns of rock strata guiding stream courses

radial drainage pattern

the arrangement of stream channels in an area where streams flow off a central peak or dome, such as occurs on a volcanic mountain

rectangular drainage pattern

the arrangement of stream channels in an area with a faulted and jointed landscape, which directs stream courses in patterns of right-angle turns

deranged drainage pattern

the arrangement of stream channels in an area with disrupted surface patterns (such as the glaciated regions of Canada) with no clear geometry in the drainage and no true stream valley pattern

parallel drainage pattern

the arrangement of stream channels in an area with steep slopes and high-velocity streams found on steep mountains

beach nourishment

the artificial replacement of sand along a beach with sand from other areas

3.5%

the average seawater salinity

traction and saltation

the bed load of a stream

wave refraction

the bending of a wave as it propagates over different depths

surface creep

the collision of saltating particles knocks them loose, forward and even airborne and promotes ____

salinity

the concentration of dissolved solids in a a solution

gradient

the degree of inclination of a stream

solution

the dissolved load of a stream

equilibrium line

the dividing line between the accumulation zone and the ablation zone in a glacier

precession

the earth's axis wobbles through a 26,000 year cycle

coral reefs

the enormous structures that corals produce as the live together in large colonies

eolian

the greek word for the work of wind

abrasion

the grinding of rock surface by the sandblasting action of particles transported in the air

spring tide

the higher tide that occurs when the earth and the moon align with the sun and pull in the same direction, increasing the gravitational force on the tides

littoral zone

the immediate coastal and shallow offshore areas

biodiversity

the interactions of living organisms and the nonliving components of the biosphere over time

rills

the interfluves direct sheetflow into small-scale downhill grooves called ____

moraine

the landform that is produced by deposited glacial sediment, composed of unsorted till

tidal bore

the leading edge of incoming tidal waters

delta

the level or nearly level depositional plain that forms at the mouth of a river

shoreline

the line of contact between the sea and the land; this shifts with tides, storms

ablation zone

the lower portion of a glacier where internal and external melting of the ice occurs

neap tide

the lower tide that occurs when the earth and moon are not aligned with the sun, which weakens the gravitational force on the tides

snowline

the lowest elevation where snow survives year-round and is the lowest point where winter snow accumulation persists throughout the summer

fluvial deposition

the process where a stream deposits alluvium, thereby creating depositional landforms such as bars, floodplains, terraces, and deltas

abrasion

the process where rock particles grind and carve the streambed like liquid sandpaper

deflation

the removal and lifting of individual loose particles by wind

hydrology

the science of water and its global circulation, distribution, and properties

longitudinal profile

the side view of a stream

hydraulic action

the squeeze-and-release action of flowing water that loosens and lifts rocks

dynamic equilibrium

the state where stream gradients adjust over time to provide just the velocity required to transport the load supplied from the drainage basin

paleoclimatology

the study of earth's past climates

biogeography

the study of the distribution of plants and animals in the biosphere over space and time

ecology

the study of the relationships between organisms and their environment

suspension

the suspended load of a stream

glacial drift

the term for all glacial deposits

capacity

the total possible sediment load that a stream can transport

water

the universal solvent

headwaters

the uppermost portions of their drainage basins where all streams start

Milankovitch cycles

the variations that affect the amount of incoming insolation the Earth receives

stream discharge

the volume of water moving past a point in a given unit of time (d x w x v)

active layer

the zone in permafrost that is seasonally frozen ground that exists between the subsurface permafrost layer and the ground surface

tsunami

these are created by sudden motions in the seafloor, caused by earthquakes, submarine landslides, or undersea volcanoes

ventifacts

these features form when windblown ice and sand erode rocks into unusual shapes in arid regions

drainage divides

these form on higher land separating drainage basins, often following along ridge tops

storm surge

these occur when high winds and surf accompanying tropical storms push seawater above the expected line

braided channels

these occur when reduced discharge lowers a stream's transporting ability, such as after flooding

nickpoints

these occur when the longitudinal profile of a stream experiences an abrupt change in gradient

permafrost

this develops when soil or rock temperatures remain below 0*C for at least 2 years

ice wedge

this develops when water enters a crack in the permafrost and freezes

beaches

this feature consists of sand particles that originated inland as rocks fragmented and weathered, then spread as sand along the coast

tombolo

this forms when sediment deposits connect the shoreline with an offshore island or sea stack by accumulating on an underwater wave-built terrace

recessional moraine

this landform forms at other points where a glacier paused between advancing and retreating

patterned ground

this occurs when the expansion and contraction of frost action sorts surface stones and soil particles into separate areas

horn

this pyramidal peak results when several cirque glaciers gouge an individual mountain summit from all sides

tides

twice-daily oscillations in sea level that range from barely noticeable to several meters

till

unsorted glacial deposit sediments of varying size

brine

water that has salinity greater than 3.5%

brackish

water that has salinity lower than 3.5%

wave trains

waves that radiate outward in all directions away from the ocean; generated by storms

mangrove swamps

wetlands that form in the tropics

salt marshes

wetlands that form north of the 30th parallel

breaker

when a wave reaches the point in which its height exceeds its vertical stability and the wave falls

kettle

when an isolated block of ice melts and leaves behind a steep sided hole that often fills with water

aretes

when cirque walls erode away, sharp ridges form called ____

desert pavement

when deflation literally blows away loose or noncohesive sediment and works with rainwater to form a surface resembling a cobblestone street, also called ____ which protects underlying sediment from further deflation and erosion

terminal moraine

when eroded debris is dropped at a glaciers farthest extent it creates this landform

frost thrusting

when freezing water causes periglacial soil to be moved sideways

frost heaving

when freezing water causes periglacial soil to be moved upward

icebergs

when glaciers in the sea calve to form floating pieces of ice called ____

(glacier) surge

when glaciers move forward with little warning and advance at velocities up to 100 times faster than normal

glacial plucking (quarrying)

when larger rocks are pulled from the bedrock or canyon walls by glaciers

longshore drift

when longshore current works with wave action to transport sand, gravel, sediment, and debris along the shore

coral bleaching

when normally colorful corals can turn white when they expel their own nutrient-supplying algae and they die

barrier spit

when sand and silt is deposited in along ridge extending out from a coast, partially blocking the mout of a bay

gelifluction

when solifluction occurs in periglacial regions

medial moraine

when two glaciers with lateral moraines join, this landform may form

blowout depression

whenever wind encounters loose sediment, deflation may remove enough materials to form basins called ____

aggradation

where a stream's bed load and suspended load exceed a stream's capacity and sediment accumulates and the stream channel builds up through deposition

accumulation zone

where snowfall and other moisture collects and compacts into ice

alluvial stream terrace

where tectonic uplift or a lowering base level rejuvenates stream energy so that a stream again scours downward and the river becomes entrenched into its own floodplain, which look like topographic steps above the river

confluence

where two tributary streams join

erosional coastlines

zones of active coastal erosion