APES 4.1 & 4.4

Troposphere

The lowest layer of Earth's atmosphere, where weather occurs and where most atmospheric gases are found.

Stratosphere

The layer above the troposphere, containing the ozone layer, which absorbs most of the Sun’s harmful ultraviolet radiation.

Ozone Layer

A region of the stratosphere with a high concentration of ozone, which protects living organisms from UV radiation.

Mesosphere

The layer of Earth's atmosphere above the stratosphere, where temperatures drop and most meteors burn up upon entry, extending from 50 to 85 km above Earth.

Thermosphere

A layer above the mesosphere, characterized by a dramatic rise in temperature due to absorption of solar radiation, extending from 85 km to 600 km, and home to the ionosphere and auroras.

temperature gradient

The amount of temperature change per unit of distance

nitrogen

78%, the most abundant gas, acting as an inert component to dilute oxygen

oxygen

21%, essential for respiration in plants and animals, and for combustion. 

argon

~1%, a noble gas that is inert

water vapor

~1%, a variable component that can range from 0% to 4%, acting as a significant greenhouse gas

carbon dioxide

~1%, a greenhouse gas that traps heat, making Earth warm enough to support life

Core

Dense mass of solid nickel, iron, and radioactive elements that release massive amount of heat

Mantle

liquid layer of magma surrounding core, kept liquified by intense heat from core

Asthenosphere

solid, flexible outer layer of mantle, beneath the lithosphere

Lithosphere

• thin, brittle layer of rock floating on top of mantle (broken up into tectonic plates)

crust

• very outer layer of the lithosphere, earth’s surface

Divergent

• Plates move away from each other

• Rising magma plume from mantle forces plates apart

Forms: mid-oceanic ridges, volcanoes, seafloor spreading, and rift valleys (on land)

Transform

• Plates slide past each other in opposite directions

Forms: earthquakes

convergent

where two tectonic plates move toward each other and collide

seafloor spreading

• Magma heated by earth’s core rises towards lithosphere

• Rising magma cools & expands, forcing oceanic plates apart

  • Creates, mid ocean ridges, volcanoes, spreading zones or “seafloor spreading”

• Magma cools,
  and solidifies into
  new lithosphere

Subduction zone/oceanic-oceanic convergent boundary

one plate subducts underneath other

• Forces magma up to lithosphere surface, forming mid ocean volcanoes

  • Island arcs

(ex. Japan)

• Off-shore trench 

oceanic-continental convergent boundary

dense (iron rich) oceanic plate subducts beneath continental plate & melts back into magma

• Forces magma up to lithosphere surface

• Coastal Mountains (Andes), Volcanoes on land, trenches, tsunamis

collision zone convergent

Continental-Continental colliding plates force surface crust upward (mountains)

• Ex: Himalayas

fault boundary transform

• Plates sliding past each other in opposite directions creates a fault (fracture in rock surface)

  • Earthquakes = most common activity

  • Occurs when rough edges of plates get stuck on each other

  • Pressure builds as plates keep sliding, but edges stay stuck

  • When stress overcomes the locked fault, plates suddenly release (up to several meters in seconds), slide past each other and release energy that shakes the lithosphere (earthquake)

ring of fire

pattern of volcanoes all around pacific plate

• Offshore island arcs (Japan) 

transform faults

likely location of earthquakes

hotspots

areas of especially hot magma rising up to lithosphere

Mid-ocean Islands (Iceland, Hawaii) 

subduction leads to volcanic activity.

one plate being pushed down, one rising with motlon magma