Plate Tectonics Cheat Sheet (DRAFT) by roobear

Spheres:
 Lithos­phere - land
 Hydros­phere - water
 Biosphere - living things
 Atmosphere - air
Layers from deepest to shallo­west:
 Inner core - solid
 Outer core - liquid
 Mantle - lower-­upper mantle is asthen­osphere and
 ­upp­ermost part is lithos­phere
 Crust - lithos­phere

Explains the origins of continents and oceans, mountain ranges and folded rocks, different rock types, earthq­uakes and volcanoes, and contin­ental drift.

The earth's lithos­phere is comprised of a number of large tectonic plates which have been slowly moving for 3.4 billion years.

Convection currents
1. Convection
Heat is generated in earth's core and convection causes it slowly rise through the mantle to the asthen­osp­here.
2. Ridge Push
The intrusion of magma pushes plates away from the ridge and they float on the convection currents of the asthen­osphere
3. Slab Pull
The denser end of the plates sink into the subduction zone.

Superc­ont­inents:
  Rodinia
  Proter­ozoic, 750 Ma
  Pangea
  Permian, 255 Ma

200 Ma ago, Pangea separated into pieces over millions of years due to tectonic activity.

Divergent - where plates divide
Crust expands, elevates, and cracks; most located at oceanic ridges.
Contin­ental rifting occurs when asthen­osphere rises and erupts, putting a rift in the plates
Convergent - where plates collide
  Oceani­c-C­ont­inental - occurs when a oceanic
  plate collides with a contin­ental plate; subduction of an
  oceanic plate forms a line of volcanoes called
  contin­ental arc; shallow, deep earthq­uakes.
  Oceani­c-O­ceanic - deep trench forms at subduction
  zone; magma erupts and forms an island arc, landward
  of trench; shallow deep earthq­uakes.
  Contin­ent­al-­Con­tin­ental - Intensely deformed
  mountain belts of pre-ex­isting contin­ental rocks.
Transform - where plates slide past each other
Large horizontal fractures or faults in the crust;
earthq­uakes are common, volcanoes are not.

The Wilson Cycle is a model that describes the opening and closing of ocean basins caused by movement of the earth's plates.
OPENING PHASE
Stage A: Embryonic - Uplifting; A plume of magma begins to thin a stable contin­ental craton
Stage B: Juvenile - Diverg­ence; The continent has been separated into 2 continents and a new ocean basin
Stage C: Mature - Diverg­ence; The ocean basin widens and the continents push away from the ridge; sediment accumu­lates along the divergent margins
CLOSING PHASE
Stage D: Declining - Conver­gent; A subduction zone forms and causes a change in plate motion direction; ocean basin remains under edge of one continent
Stage E: Terminal - Conver­gent; Remnant ocean basin subducts, continents about to collide.
Stage F: Suturing - Conver­gence and uplift; Collision of the 2 contin­ental blocks occurs forming a mountain, closing the basin
Stage G - Mountains erode (penep­lain) and tectonic stability returns