FORCES OF CHANGE

• tectonic plates - called lithospheric plate is a massive, irregularly shaped slab of solid rock composed of both continentsl and oceanic lithosphere
• 3 changes in earth surface

  1. continental drift theory
  2. Seafloor spreading
  3. Theory of plate tectonics
• Continentsl drif theory - the continents drifted apart and collided to form the supercontinent Pangea
• continental drift theory was proposed by Alfred Wegener in 1912
• continental drift theory- the break up of the supercontinent
• Sea floor spreading - The movement of oceanic crust away from the mid-ocean ridge
• Sea floor spreading is the process where two tectonic plates move away from each othe then the rock breaks and forms a crack between the plates
• Plate Tectonics - The theory that Earth's outer layer is made up of several large pieces called plates
• Continental drift - The theory that the continents are slowly moving apart or coming together
• Mid-Ocean Ridge - A chain of mountains under the sea which runs through the Atlantic Ocean
• Continental drift - A hypothesis proposed by Alfred Wegener to explain how continents could have moved apart over time.
• Sea floor spreading was formulated by a geologist and nary submarine commandar Harry Hess
• Theory of plates tectonics - the solid part of earth composed of seven major subjects and several minor parts called plates
• Compositional layers

  A) Crust

  B) Mantle

  C) Core

  
• Mechanical layers

  A) Lithosphere

  B) Asthenosphere

  C) Mesosphere

  D) outher core

  E) Inner core

  
• how did the scientist believe wegener - they discovered that magma is rising up through cracks ( how new lands is created )
• how did the scientist believe wegener - they have been plotting the locations of earthquakes and volcanos and observes that follow the pattern that wegener explained
• The plates tectonics theory is based on concepts proposed by Alfred wegener
• The lithosphere is divided into continent-sized plates that are constantly moving
• The continents were once part of the supercontinents called pangaea
• lithosphere plates moves 1-2 inches a year
• boundaries are where plates meet
• 3 types of plate tectonic

  1. conceraent - where plate meets/collides
  2. Transform - where plate slides past one another
  3. divergent- where plates move apart
• Volcanoes and mountains form as a result of convergent boundaries colliding
• Earthquakes and tsunamis accur at convergent and transform boundaries
• fissures, cracks and rifts in the surface occurs at divergent boundaries
• Sea floor spreading occurs at divergent boundaries on the ocean floor
• TRANSFORM PLATE BOUNDARY - Plates slide against each other in opposite directions. No mountains or volcanoes are formed but only earthquake results. No subduction, no volcanoes and magma
• crust is the outer layer of the Earth
• the mantle is made up of magma and rock
• Plate tectonics is the theory that explains how the continents move around the world.
• lithosphere is broken into many small and large slabs of rocks called tectonic plates
• The process by which the ocean floor sinks beneath a deep-ocean trench and back into the Mantle is called subduction
• The place where two plates move apart is called a divergent boundaries
• a ocean ridge is a long chain of mountains that is found underwater
• the process continuously adds new material To The ocean floor is called seafloor spreading
• A deep ocean trench is a deep underwater canyon
• A place where two plates slip past each other is called a transform boundaries
• a well-tested concept that explains the wild range of a wide range of observations is called a scientific theory
• The place where two plates come together is called a divergent boundaries