By: Renee Moran
What Are Plate Tectonics?
Make up of the Earth
The Earth is made up of three main layers; the crust, mantle, core
Crust- the rocky outer layer of Earth that we live on, it consists of less than 1% of Earths volume.
Mantle- the silicate rock rich in magnesium and iron under the crust. The mantle is more than two thousand miles thick and accounts for more than three-quarters of the volume of the Earth.
Core- the core is made up of an inner and outer layer. The solid inner core of iron and liquid outer core of nickel-iron alley.
Is a scientific theory that the continents are always moving; it is the gradual movement of the continents across the earth's surface through geological time.
Alfred Wegener is credited with developing the hypothesis for continental drift.
Evidence for Continental drift
Alfred Wegener's primary sources of evidence included the fit of the continents, with the shores of the continents fitting together. Indicating that there once was a super continent known as Pangaea. Another part of key evidence is fossils that have been found on separate continents being the same.
Sea-floor spreading & who dicovered it
Harry Hess was one of the discoverers of sea-floor spreading and is credited with the discovery.
Sea floor is caused by two plates moving apart; this is caused by plate tectonics. Continental drift is also caused by plate tectonics. Therefore, we can conclude that continental drift is related to sea-floor spreading. When the plates move, it carries the continents with it and thus the continents drift away from each other. Sea-floor spreading is a result of divergent boundaries in the ocean crust.
How convection helps with plate tectonics
Theory of Plate tectonics
Different types of boundaries
convergent with subduction
Convergent with subduction is when an oceanic and continental plate collide and the oceanic plate sinks underneath (oceanic crust is thinner). This creates trenches that results in the Marianas trench. This process can also cause volcanoes that made the Hawaiian islands and the Andes Mountains both made by volcanoes as a result of convergent with subduction.
Ring of fire
The Ring of Fire is an area where a large number of earthquakes and volcanic eruptions occur in the basin of the Pacific Ocean. In a 40,000 kilometer horseshoe shape, it is associated with a nearly continuous series of oceanic trenches, volcanic arcs, and volcanic belts and/or plate movement.