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
