General Geo

• The mantle is more than 82 % of the earths volume that extends 2900 km
• The lithosphere consists of the crust and uppermost mantle
• Principal divisions of earths surface: Continents and Ocean basins
• Continental crust is thicker, less dense, lighter and older than oceanic crust.
• Plate tectonics theory states that the Earth's outer layer is divided into several large plates which move slowly over the asthenosphere (the plastic part of the mantle).
• Convection currents are caused by heat from the core
• Sea floor spreading occurs when magma rises from the mantle to fill gaps between two continental plates or an oceanic plate and a continental plate.
• Divergent boundaries occur where two plates are moving away from one another.
• Sea floor spreading occurs at mid-ocean ridges where new material is added to the plate boundary
• Subduction zones occur when two plates collide and one subducts beneath another
• Transform faults occur when two plates slide past each other
• The mid-Atlantic Ridge is where sea floor spreading takes place
• Transform faults occur at right angles to divergent boundaries
• Destructive margins form when two plates collide at an angle
• Constructive margins form when two plates collide head on
• Triple junction is defined as the area where 3 plates meet
• Continental shelf


  A gently sloping platform that extends seaward from the shore
• Continental slope


  Boundary between continents and deep ocean basins, a steep drop-off that extends from the outer edge of the continental shelf to the floor of the ocean
• Continental rise


  In regions where trenches do not exist, the steep continental slope merges into a more gradual incline. The continental rise consists of a thick wedge of sediment that moved downslope from the continental shelf and accumulated on the deep ocean floor
• Deep ocean basins


  Lies between the continental margin and oceanic ridges
• Abyssal plains


  Parts of ocean basins and are flat features
• Deep ocean trenches


  Extremely deep depressions that are occasionally more than 11,000 meters (36,000 feet) deep. Relatively narrow and represent only a small fraction of the ocean floor
• Seamounts


  Submerged volcanic structures
• Mid-ocean ridges (MOR)


  Most prominent feature on the ocean floor
• MOR is short for Mid-ocean ridges
• Mineral formation

  1. Precipitation of mineral matter from a solution

  2. Crystallization of molten rock by cooling

  3. Mineral matter depositions as a result of biological processes
• Luster


  The appearance or quality of light reflected from the surface of a mineral
• Transparency


  Ability to transmit light-When no light is transmitted, the mineral is described as opaque, when light, but not an image, is transmitted through a mineral sample, the mineral is said to be translucent. When both light and an image are visible through the sample, the mineral is described as transparent
• Color


  The color of a mineral in its solid form
• Streak


  The color of a mineral in powdered form
• Tenacity


  Describes a mineral's toughness, or its resistance to breaking or deforming
• Hardness


  A measure of the resistance of a mineral to abrasion or scratching. This property is determined by rubbing a mineral of unknown hardness against one of known hardness or vice versa
• Continental volc arcs

  Produced by volcanic activity associated with the subduction of the oceanic lithosphere (oceanic+continental)
• Volc Island Arc

  Volcanic arcs located 100-300 km away from a trench (oceanic+oceanic)
• Volc Island Arc


  • Aleutian
  • Mariana
  • Tonga islands
• Volc Island Arc

  • Located 100-300 km away from a trench
• Fracture zones

  Inactive extensions of transform faults
• Slab Pull


  Results from the sinking of a cold dense slab of oceanic lithosphere and is the major driving force of plate motion
• Ridge Push


  Gravity driven force that results from the elevated positions from the ridge which causes slabs of lithosphere to slide down the flanks of the ridge
• Nearly 5B years ago, a cloud of gasses contracted due to gravitational interactions