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what is albedo
fraction of solar energy reflected by surface of planet or moon
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carbon cycle
geosystem of the movement of carbon among atmosphere & lithosphere, hydro & bio
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el nino
anomalous warming of easter tropical pacific ocean occurs 3-7 yrs, lasting +/- year
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green house effect
global warming via atmosphere w/ greenhouse gases radiating solar energy back less efficiently
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milankovitch cycle
astronomical; causes periodic variations in the amount of heart earth gets from sun. cycles include: eccentricity of earths orbit, tilt of earth & precession: wobble on axis of rotation
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hanging valley
valley left by melted tributary glacier that enters large glacial valley, high on wall
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kettle
hollow depression w/ steep sides & maybe occupied of water: formed in glacial deposit
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moraine
accumulation of rock, sandy, clayey material carried by glacial ice & deposited as till
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permafrost
permanently frozen rock & ice: below 0 degrees for 2 yrs
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plastic flow
total of all small movement of ice crystals that make up glacier -> results in large movement
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striation
scratch/groove on bedrock by overriding ice
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till
unsaturated & poorly sorted sediment w/ all sizes of fragments deposited by glacial action
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ablation
the total amount of ice that a glacier loses each year
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basal slip
the sliding of a glacier along its base
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cirque
hollow, half inverted cone-like shape formed at the head of glacial valley by tearing & plucking action of ice
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crevasse
vertical crack on surface of glacier from movement of brittle surface ice via plastic flow
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drumlin
streamlined hill of till & bedrock that parallels ice movement of continental glacier
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esker
long, narrow ridge of sand/gravel in middle of a ground moraline
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fjord
formed glacial valley occupied by sea
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principal or original horizontality
sediments are deposited under the influence of gravity as nearly horizontal beds
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principle of superposition
each sedimentary layer of an undisturbed sequence is younger than 1 beneath it & older than above -> a younger layer cannot be deposited under old
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principle of faunal succession
the layers of sedimentary rocks in out crop have fossils in sequence
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cross-cutting relationships
dikes can cut through sedimentary layers, sills can be intruded parallel & faults can displace bedding planes, dikes & sills
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sequence stratigraphy
basic geologic unit observed by the seismic imagine of sediments in a series of beds bounded above & below by unconformities
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chemical stratigraphy
chemical finger prints that extend regionally/globally which can help match sedimentary rocks
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paleomagnetic straitgraphy
reversals of earths magnetic field recorded in the orientation of magnetic minerals in volcanic rocks
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detrital sedimentary
made of pieces of pre-existing rocks -> differientated by grain size (micro, sand, macro)
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organic sedimentary
made of organic material produced by plants/animals -> distinguishable by hardness
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inorganic chemical sedimentary
when sediment precipitates from water
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non-foliated metamorphic
macro texture -> formed by contact metamorphism, generally 1 mineral
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foliated metamorphic
maybe shiny -> quartzite & marble
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P-Wave
the 1st seismic wave to arrive from the focus of an earthquake
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S-Wave
- the 2nd seismic wave to arrive from the focus of an earthquake
- *Travel 1/2 as fact as P-Waves (17000m/hr OR 8km/sec)
- *The longer the P-S interval, the further away the quake
- *distance to an earthquake = measure P-S interval & compare a time v. distance graph
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polar cell
air circulated in troposphere, warm air rises at lower latitudes & moves poleward through upper troposphere, when it reaches poles, it cools & descends as cold, dry high pressure area
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coriolis effect:
- deflection of moving object when viewed from rotating reference frame
- *earths rotation on axis
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doldrum
intertropical convergence zone, low calm winds
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jet stream:
fast flowing, narror air current between troposphere & stratosphere
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thermohaline circulation
3D pattern of ocean circulation driven by differences in temperature & salinity: important of ocean-atmosphere climate system
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atmosphere
mixture of gases: 78% nitrogen, 21% nitrogen
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troposphere
3/4 mass of atmosphere, lowest level (11 KM), responsible for weather
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stratosphere
cold, dry layer above troposphere going to 50 km has most of the ozone
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hadley cell
closed circulation loop beginning at equator w/ warm, moist air, lifted in low pressure areas
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ferrel cell
mixing between hadley & polar southern overrides hadley, northern overrides polar
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continental interior desert
inland desert formed b/c by the time air masses reach interior, they have lost moisture
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polar desert
annual precipitation less than 250 mm & high temp of 10 degree c
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ephemeral stream:
stream that flows only after rain/snow-melt & has no base flow component
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sand dune prerequisites (3)
- 1) abundant supply of loose sand in a region generally void of vegetation
- 2)a wind energy source sufficient to move sand
- 3) topography where the sand loses momentum & settles
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kinds of sedimentary rocks (3)
detrital, organic & inorganic
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playa lake
permanent/temporary lake in arid mountain valley or basins
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slip face
steep lee slope of a dune on which sand is deposited in cross-beds at angle of repose
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ventifact
wind-faceted pebble with several curved/flat surfaces that meet at sharp ridges via sandblast
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subtropical desert
warm & arid, average temp above 32 degree f w/ annual rainfall less than 50cm & usually less than 25 cm, no vegetation
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trade wind desert
little rain & high temp that occurs when winds blow over land
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rain shadow desert
area of land that receives reduced precipitation due to close proximity to mountain
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deflation
removal of dust, silt & sand from dry soil by strong winds that make depressions
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desert pavement
ground too large for the wind to move, deflation removes fine particles
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desert varnish
dark brown, shiny mix of clay, manganese & iron oxides on rock surfaces
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loess
blanket of unstratified, wind-deposited, fine-grain sediment rich in clay minerals
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pediment
broad, gently sloping platform of bedrock left behind as a mountain front erodes
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igneous rocks
form by crystallization from magma
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intrusive igneous
crystallie when magma intrudes into unmelted rock
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extrusive igneous
- form from rapidly cooled magmas that erupt at surface via volcano
- *quartz, feldspar, mica, pyroxene, olivine
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sedimentary rocks
- formed by sediments of sand, silt, shells. layer when deposited
- *lithified (held together) by: compact or cementation
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metamorphic rock
formed by high pressures on igneous, sedimentary or metamorphic which chemically changes them
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what are the physical properties of minerals (5)
hardness, clevage, fracture, color & streak
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what is hardness (in terms of properties of minerals)
- measure of the ease w/ which the surface can be scratched
- *depends on chemical bonds
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what is cleavage (in terms of properties of minerals)
- tendency of a crystal to break along flat planar surfaces
- *high bond strength = poor cleavage
- * low bond strength =good cleavage
- *covalent bond = poor/no cleavage
- *ionic bond = very good cleavage
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fracture (in terms of properties of mineral)
tendency to break on irregular surfaces
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barchans
cresent-like dunes usually in groups. horns of crescent go downwind. products of limited sand & unidirectional wind
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blowout dunes
reverse of barchans -> slip face is convex downwind
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transverse dunes
long ridges oriented at right angles to the wind direction. form in arid place w/ abundant sand & no vegetation
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linear dunes
long ridges of sand oriented parallel to wind direction reach height of 100 M. formed w/ moerate sand supple rough pavement & constant wind direction
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thermal inversion
- movement of cold air above & hot air below in reverse positions
- *Thermal inversion occurs when a layer of warm air settles over a layer of cooler air that lies near the ground. The warm air holds down the cool air and prevents pollutants from rising and scattering.
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background radiation
radiation that is always occuring
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groundwater aquifier
underground water that flows downhill, cannot permeate clay
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horn
glaciers that changed the appearance of a land form to sharp & jagged
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