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Terms in this set (75)
What is geomorphology?
science of the land surface
& physical n chemical processes that result in landforms
what are the three types of time?
steady, graded and cyclic
what is steady time
no changes in form
short term period
what is graded time
average condition maintained
periodic fluctuations about mean
medium time period
what is cyclic time
gradual overall change
long term period
equilibrium is never reached
what is a landform
element of the landscape that can be observed in its entirety and has consistence of form
what is a landscape
each surfaces composed of an assemblage of subjectively defined, lesser surfaces from a particular vantage point
what is a geomorphic system?
set of related landforms and processes, defines in terms of a dominant agent of geomorphic activity
what is the difference between physical and climatic geomorphology
physical = observational
climatic = distinctive climate
what is the history of geomorph
first people to examine - greek
neptunist - marine processes
vulcanists- subsurface heat pushed to the surface
what is James huttons law
uniformity of law - the assumption that natural laws are constant in time and space
what is uniformity of process?
if past events can be explained then additional unknown causes should not be invoked
what is uniformity of rate?
changes to the Earth's surface are usually slow, steady, and gradual... major events
what is uniformity of state?
earth has always looked like this
who is bernhardi
published first evidence of continental glaciations in north Germany
what are the concepts of landform evolution
1. geologic structure is a dominant control factor of landforms and is reflected in them
2. landscapes can be classified in stages of youth, maturity, old age
3. geomorphic processes leave their distinctive imprint upon landforms
what is endogenetic
energy form landform and landscape development comes from within the earth... internal
what is exogenetic
processes for which the energy is derived from earths surface... external
what are equilibrium systems
material, process and geometry form a self-correcting balance... lakes, rivers, glaciers
what is an eratic?
boulder/ rock unlike local rocks
come from miles away
who is Louis Agassiz?
swiss geologist who observed glaciers
determined that glaciers explain erratic boulders
proposed that ice age froze Europe
what can ice do?
carry and drop boulders and fine grained, unsorted soil
how much of earth was covered by ice during the Ice Ages?
when did the most recent ice age end?
11 thousand years ago
When were some important ice ages?
What are the 6 definitions of a mineral
what is ice as a sed. ig. and met. rock
igneous= lake ice
what is a glacier
thick mass of recrystallized ice that deforms under its own mass on land
descriptions of a continental ice sheet
vast ice sheets covering large land areas
ice flows outward from thickest part of sheet
what are the two major ice sheets that are still on earth?
Greenland and antarctica
how does a glacier form
snow must be abundant; more snow fall than melt
snow must be removed by avalanches or wind
how is a glacier sustained by latitude
polar regions = glaciers form at sea level
equatorial regions = glaziers form above 5km elevation
Know how to draw the formation of glacial ice!!!!!!!
What are the two different forms of glaciers
wet bottoms glaciers and dry bottom glaciers
what is a wet bottom glacier
air temp, ice temp, pressure of ice ---> PMP (pressure melting point)
what is a dry bottom glacier
cold base it frozen to substrate
what are the two types of mechanical behavior (memorize the chart!!!!!)
stress and strain
How is the movement of glacial ice described
ice flows downhill via gravity
rate of flow varies widely - 10 to 300 m/year
what is plucking (observe picture!!!)
ice breaks off and removes bedrock fragments
ice melts by pressure against the up-ice side of an obstruction
what is glacial abrasion?
sandpaper effect on substrate
what is a horn
top of mountain
formed by 3 or more cirques
what is a cirque
bowl-shaped basin high on a mountain
What is an arete?
ridge between 2 u-shaped valleys
what is a hanging valley
intersection of a tributary glacier with a truck glacier
What is a fjord?
u-shaped glacial troughs floored by sea
what is a moraine?
unsorted debris dumped by a glacier
What is cavitation?
pressure indues air bubble formation and collapse
glacial sediment transport descriptions
glaciers act as large scale conveyor belts
pick up, transport, and deposit sediment
sediment transport is always in ONE DIRECTION
what is an end moraine
debris at toe of glacier
What is glacial till?
unsorted glacial sediment deposited directly by a glacier
What is a varve?
coarse-fine couplets of stratified sediments
What is loess?
wind transported silt
What is a drumlin?
long aligned hills molded lodgment til
what is an esker?
A long sinuous ridge of sand and gravel
Remember isostatic rebound!!!!
glaciers are heavy!!
takes time to readjust
what is the sea level during ice age?
what is the sea lever after ice age?
remember that the drainage system changes!!
used to flow north
what are the long term causes of glaciation
what are the short term causes for glaciation
where the ice is frozen and then not
What is weathering?
Weathering is the breaking down of rock over a long period of time.
What is regolith?
unconsolidated layer of broken rock and altered material
left from weathering
what are some examples of the functioning weathering?
gives rock lower strength and greater permeability
produces minor landforms insoluble rock
releases minerals in solution
first step in soil formation
what is the layer of soil
what are the two distinctions of mechanical weathering?
volume change in rock mass
volume change of pore space/cracks
what are examples of change in volume of rock?
what are examples of change in pore space
blocky v. platy breakage
platy - like mica- more surface area opposed to blocky
what is chemical weathering
The breakdown of rock by changing its chemical composition
what are the types of chemical weathering?
disolution, carbonation, hydrolysis, oxidation, reduction
what is dissolution
selective removal of soluble materials by combining with water
What is carbonation?
forms weak carbonic acid by combining water with CO2
what is hydrolysis
addition of water to structure
What is oxidation?
chemical union of free oxygen with metallic elements
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