exam 2 Flashcards
mantle
a layer inside a planetary body bounded below by a core and above by a crust
crust
thin outer, rocky layer of earth
thicker crust is more elevated than thinner crust
core
the very hot, very dense center of our planet
lithosphere
rigid, relatively cool outermost shell that consists of the crust and the uppermost mantle
- average thickness of 100 km
- more than 250 km thick below oldest portions of continents
asthenosphere
- soft relatively weak layer of the mantle
- temp/pressure conditions are such that rock is near its melting point and is easily deformed
lower mantle
lower relatively more rigid layer of the mantle
- increasing pressure results in increasingly stronger rocks between 660 km and 2900 km
- still some deformation of rocks
outer core
liquid shell of iron nickel alloy that is 2260 km thick
- the flow of metallic iron in this zone generates the earths magnetic field
inner core
solid sphere of iron nickel alloy with a radius of 1216 km
- temperatures high enough to melt iron but the immense pressure compresses it into a solid state
continental crust
the outermost layer of Earth’s lithosphere that makes up the planet’s continents and continental shelves
theory of plate tectonics
- the earths lithosphere is broken into numerous slabs called tectonic plates
- the plates are in continual motion, 2 inches per year
- rigid lithosphere plates move about on the asthenosphere which is softer and capable of gradual flow
oceanic crust
the part of the Earth’s crust that makes up the seafloor
bathymetry
measurement of ocean depths and charting of the ocean floor topography
passive continental margins
are not
associated with tectonic plate boundaries.
Includes the continental shelf, slope and rise.
continental shelf
the gently sloping, submerged perimeter of
a continent.
– Very gentle slope: 2 m per km (0.1 °)
continental slope
a relatively steep structure that
marks the transition from continental to oceanic crust
turbidity currents
gradual incline extending from the base of the continental
slope to the deep-ocean basin
continental rise
gradual incline extending from the base of the continental
slope to the deep-ocean basin.
active continental margins
areas where oceanic
lithosphere is being subducted beneath the leading edge
of a continent.
deep ocean trenches
Surface expressions of subduction zones are
subduction zone
areas where oceanic lithosphere is descending
(being subducted) into the underlying asthenosphere
volcanic arcs
arc-shaped chain of volcanoes that forms
adjacent to a subduction zone.
hotspot
areas of volcanism and high heat
flow associated with a rising plume of hot
mantle material
accretionary wedge
sediments and pieces of oceanic crust
scraped from descending plate and plastered against edge of
the overriding continent
how guyots and atolls form
seamounts
divergent plate boundaries are located
plates pulling apart=
why are mid ocean ridges elevated
a broad linear mountain system associated with a well developed plate boundary
paleomagnetism
study of the record of earths magnetic filed preserved in rocks
seafloor basalts recorded??
paleomagnetism provided??
what causes seasons?
When the earth’s axis points towards the sun, it is summer for that hemisphere. When the earth’s axis points away, winter can be expected.
why do higher latitudes receive less solar radiation?
curvature of the earth, angle of solar radiation is smaller
absorption
conversion to thermal equals increasing temperature
reflection
radiation bounces back from an object at the same angle
scattering
a beam of light is broken into a large number of weaker waves traveling in different directions
atmosphere is a selective absorber of?
how do greenhouse effect work
without the greenhouse effects earths average temp would be -18 c
albedo
the fraction of the total radiation that is reflected by a surface
how does albedo influence air temp
low albedo surfaces meet more infrared radiation which heats the air above
high albedo surfaces reflect visible light which does not heat the air above
why air temp above water us less variable than air temp above land
how air temp is affected by
altitude
how air temp is affected by
inland areas vs coastal areas
how air temp is affected by
differences in latitude (polar vs tropical)
how will cloud cover will have on night and day temps
what the most abundant gas is in atmosphere
nitrogen
2nd most abundant gas in atmosphere
oxygen
aerosols
suspended microscopic solid and liquid particles
what is a ozone and why is it so important
concentrated in the stratosphere
- blocks out harmful uv radiation from the sun making earth habitable for life
how emissions of cfcs by human activity is harmful to the ozone layer
atmospheric pressure
air pressure decreases when?
4 layers of atmosphere from lowest to highest
- troposphere
- stratosphere
- mesosphere
-thermosphere
-exosphere
environmental lapse rate
The rate at which the air temperature changes with height in the atmosphere surrounding a cloud or a rising parcel of air.
evaporation vs condensation of water
how is relative humidity is calculated
dew point temp
temp the air needs to be cooled in order to achieve a relative humidity
orographic lifting
change to airflow when the elevated terrain such as mountains forces air upward
cumulus
have the appearance of rising domes or towers and typically have a flat base
stratus
layer or sheet like clouds that cover much or all of the sky
cirrus
high thin clouds composed of ice crystals
precipitation
water released from clouds in the form of rain, freezing rain, sleet, or hail
rain
drops of water produced by cumulonimbus and nimbostratus
drizzle
liquid water drops that are smaller than those of rain
snow
ice crystals or clumps of crystals that fall from clouds
sleet
small pellets of ice that forms when raindrops fall through a subfreezing layers of air
glaze
a coating of ice generally clear and smooth formed on exposed objects by supercooled water droplets
hail
precipitation in the form of hard rounded pellets or irregular lumps of ice
how does a thunderstorm form large hailstones?
when raindrops are carried upward by thunderstorm updrafts into extremely cold areas of the atmosphere and freeze.
