Ch. 1 – Earth’s Systems & Resources

Earth
3rd rock from the sun, supports life, approx 4.6 billion y/o
Geologic Time Scale
span of time on Earth, grouped by the changes on Earth
Eon
largest span of time on geologic time scale; Archean, Proterozoic, Hadean, Phanerozoic
Era
2nd largest span of time; includes Paleozoic, Mesozoic, and Cenozoic
Period
3rd largest span of time; divided from eras
Precambrian time
the eons Hadean, Archean, and Proterozoic ; first eons; starts 4.55 billion yrs ago
Crust (in relation to Earth’s layers)
outermost layer of Earth; continental or oceanic; can fracture & lead to Earthquakes
Oceanic Crust
denser than other type; made of basalt (contains Fe and Mg); 3-6 mi thick
Continental Crust
high amount of granite (rich in Al); 22-44 mi thick
Mantle
makes up 80% of Earth’s volume; has upper/lower level; 1,802 mi thick
lithosphere
Earth’s crust and upper mantle; rigid outer layer of Earth; broken into tectonic plates
asthenosphere
below lithosphere, above lower mantle; plastic-like substance that tends to flow
lower mantle
semi-rigid, flows very slowly; part of mantle
core
center of the Earth; inner/outer layers; made of Fe and Ni
inner core
core layer; solid bc of extreme pressure from outer layers; 746 mi thick
outer core
core layer; molten bc of extreme heat; 10,832F; 1,249 mi thick
seafloor spreading
movement of the seafloor at the mid-ocean ridge
mid-ocean ridge
location where magma rises to surface; as it rises, it pushes away existing seafloor to make it spread apart
transform plate boundaries
faults; at zone of transform plate boundaries, slide in sideways motion; when pressure releases, causes EQs. i.e. San Andreas Fault & Alpine Fault (New Zealand)
Divergent plate boundaries
2+ plates pull away from each other; i.e. mid-ocean ridges or E. Africa Rift Valley
Convergent Plate Boundaries
2 plates move toward each other and one goes under the other; i.e. Andres Mtns (S America), Cascade Mtns (USA), Marianas Trench (Pacific Ocean)
Subduction
oceanic and continental plates in collision, with denser oceanic plate pushed below continental plate; why continental crust older than oceanic
Earthquake
pressure released from build up of transform plate boundaries being pushed together then released
strike-slip faults
occur when plates slide past each other horizontally
normal faults
caused by tension from pulling apart motion
reverse faults
formed from compression
volcanoes
openings in Earth’s surface that allow magma, gas, ash, cinder, etc to escape from mantle
shield volcano
large, broad sides, gradual slopes, usually have crater on top, typically erupt slowly. i.e., Mauna Loa (Hawaii), Mt Wrangwell (AL)
Composite/Strato Volcanoes
tall; symmetrical; steep; built from alt layers of ash, lava, cinders; explosions unpredictable. i,e, Mt Shasta (CA) & Mt. St. Helens (WA)
cinder cone volcanoes
made of lava that erupts in the form of cinders, which are blown into the air & settle around volcano opening; most common type. i.e. Crater Lake’s ex-volcano
Health Effects of Volcano Explosions
poor air quality, respiration problems, bone degeneration(Hydrogen Flouride); suffocation (ash/CO2); acid rain (SO2/HCl, HF)
Atmospheric Effects
ozone can be broken down (diminishes as gases reduce in atmos); global warming; contribute to smog; block out solar radiation/lower mean temps
Seasons
caused by tilt of Earth’s axis to its orbital plane & rotation around the sun
Perihelion
when Earth is closest to the sun (Jan)
Aphelion
Earth farthest from sun (July)
Nitrogen (N)
78% of Earth’s atmos
Oxygen (O)
21% of ttl comp of atmos
Weather
short-term events of temp, wind, percipitation
Climate
avging daily weather for at least 30 yrs
Hadley air circulation cell
occur close to equator; air warmed by strong solar radiation & rises; cools as it rises and sinks (0 to +/-30F)
Ferrel air circulation cells
occur at mid-latitudes; sinking air from Hadley cells and rising air of Artic cells create westerly surface winds
Polar air circulation cells
northernmost cells; contain cold, dense air moving toward poles, where it inks and moves back to mid latitudes
Coriolis effect
creates deflection of objects otherwise moving in a straight line bc of E’s rotation; causes winds in N. Hemi to deflect right and S. Hemi to deflect left
El Nino
period of ocean warming in e. tropical Pacific Ocean; surface waters heat up bc of undercurrents; air surface pressure increseases, creating milder climates in n US & wetter conditions in e US/Peru & SE Asia drier
La Nina
surface water temps colder than usual; occurs in 3-7 yr cycles
Freshwater
2.5% of water; 21% of the 2.5% is in form of groundwater/water vapor/lakes/rivers
saltwater
3.5% salt; most of the water on earth; main salts being NaCl, MgCl, & CaCl
parent material
core component of soil
biological weathering
daily activities of organisms moving through/over souk
physical (mechanical) weathering
rock material broken down w/o chemical changes taking places (i.e. wind, water)
chemical weathering
chem rxns occur from H2O & atmos gases reacting w/ parent material
O Horizon (organic litter)
outermost layer of soil profile; composed of organic layer, inc. living organisms
A Horizon (topsoil)
mix of organic matter w. inorganic materials; inc weathered parent material; essential in plant growth/productivity (2nd layer); contains most nutrients for plant growth
E Horizon (eluviated)
3rd layer deep; mainly mineral material
B Horizon (subsoil)
contains many items leached from above soil layers (4th layer deep)
C Horizon (minimally weathered)
2nd to deepest layer of soil profile; weathered from parent material; experienced minimal erosion; contains mainly larger fragments
R Horizon (bedrock)
parent material; deepest layet
Soil Porosity
amt of open space between each soil particle; ratio to void space to ttl volume
Soil Permeability
ability for liquid to flow through soil
Clay
fine particles; low permeability; particle diameter is less than .002 mm
Silt
fine particles but larger thann clay. .002 to .05 mm
Sand
larger than silt; high permeability; .05 to 2mm; not condusive to plant growth
Loam
mixture of sand, silt, & clay; soils with pH clos to neutral are ideal for agriculture